Annals of WULS. Forestry and Wood Technology No 72

Transcription

Annals
of Warsaw
University
of Life
Sciences
– SGGW
Forestry and Wood Technology No 72
Warsaw 2010
Contents:
BARBU S. M., BADESCU L.A.M., JAVOREK L. “Studies concerning the chip
formation at the longitudinal drilling of the beech wood with help high speed camera”... 9
DUCHNICZ K., WASIELEWSKI R.
“Computational method for determining the static stiffness of the saw blade”.................. 13
DUCHNICZ K., WASIELEWSKI R.
“Effect of the saw blade geometry at its static stiffness”.................................................... 17
FABISIAK BEATA, DZI GIELEWSKI STANIS AW “Evaluation of the design
impact on the performance of polish furniture enterprises”................................................ 21
MOLI SKI WALDEMAR, FABISIAK EWA, SZWABA TOMASZ
“Properties of thermally modified ash wood (Fraxinus americana) in the aspect
of its affinity to water”........................................................................................................ 27
MOLI SKI WALDEMAR, FABISIAK EWA, RODECKI UKASZ
“Selected mechanical properties of thermally modified American ash wood”................... 32
MOSTOWSKI RAFA “The influence of long-lasting permanent load with pulling
out force on pin displacement in locally strengthened elements of furniture joints”.......... 37
MOSTOWSKI RAFA “The evaluation of influence of particle boards local
strengthening in the area of pins set in furniture joints – rheological aspect”.................... 42
MOSTOWSKI RAFA , WIELOCH GRZEGORZ “The ranges of local influence of
PUR 555.6 preparation and load-carrying and stiffness of furniture joint elements”......... 47
MYDLARZ KATARZYNA
“Contemporary timber-frame construction systems in Poland”.......................................... 52
NICEWICZ DANUTA, DANECKI LESZEK
“Recycling of insulation boards by reuse”.......................................................................... 57
NICEWICZ DANUTA, PODLE NA BEATA
“Influence of freeness of pulp on properties of hardboards”.............................................. 62
NIEMZ PETER, SONDEREGGER WALTER, HERING STEFAN “Thermal
conductivity of Norway spruce and European beech in the anatomical directions”........... 66
NOVÁK IGOR, SEDLIA IK JÁN, JURKOVI PETER, POLLÁK VLADIMÍR,
ANTAL PAVOL “Development of new types of nanocomposite hot-melt adhesives”..... 73
NOVÁK IGOR, SEDLIA IK JÁN, FLORIÁN ŠT PÁN, MATYAŠOVSKÝ JÁN,
ERVINKOVÁ DANICA
“Properties of pressure-sensitive adhesives using special filler”........................................ 79
NOVÁK IGOR, CHODÁK IVAN, SEDLIA IK JÁN, ŠTEVIAR MARIAN,
POPELKA ANTON, KOPNÝ JÁN
“Investigation of poly(ethylene terephthalate) treated by low-temperature plasma”.......... 83
OLE SKA SYLWIA, ROSZKOWSKI MICHA , CICHY ANDRZEJ, BEER PIOTR
“Analysis of geometrical deformations of furniture fronts”............................................... 90
ORLOWSKI K. A., WIERZBOWSKI M. A. „Selected mechanical properties of
steam kiln–dried wood determined on the basis of cutting power”.................................... 95
ORLOWSKI K. A., OCHRYMIUK T.
“The prediction method of the shear angle in the cutting zone during wood sawing”....... 99
ORLOWSKI K. A., OCHRYMIUK T., ATKINS A.
“Specific cutting resistance while sawing of wood – the size effect”................................. 103
PA UBICKI B., SZULC M., SYDOR M.
“Technological aspects of electronic systems production on wood-based PCBs”............. 108
PARYS TOMASZ “Analysis of web page creation technologies used on websites of
selected kitchen furniture manufacturers”........................................................................... 113
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PARYS TOMASZ “Website creation script technologies – a comparative analysis of
compatibility with the W3C standards in Polish furniture industry portals and vortals”... 119
PAVLOVI S GUN RS, DOLACIS J NIS, ANTONS ANDIS, C RULE DACE
“Relationship between the anatomical structure elements and physical properties
in the trunk transverse and longitudinal direction for wood of Norway spruce
(Picea abies (L.) Karst.) growing in Latvia”....................................................................... 124
PERZYNA K. , KOLBRECKI A. “Wooden houses and fire safety rules”........................ 129
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”........................................................................................ 132
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“
”........................................ 136
PINKOWSKI GRZEGORZ, SZYMA SKI WALDEMAR
“Quality of profile milling on a cnc woodworking machine”............................................. 141
PINKOWSKI GRZEGORZ, SZYMA SKI WALDEMAR, KRAUSS ANDRZEJ
“Impact of the cutting edge condition on the results of oak wood milling”........................147
PINKOWSKI GRZEGORZ, ZAKRZEWSKI WIES AW, JOKIEJ MAGDALENA,
KRAUSS ANDRZEJ
“Investigations on the execution accuracy of floor boards”............................................... 153
PODZIEWSKI PIOTR, GÓRSKI JAROS AW “Feed rate influence on feed force
and cutting torque while drilling in MDF (Middle Density Fibreboard)”.......................... 160
POHL PIOTR
“Studies on heat-transfer coefficient of wood floor materials used in floor heating”........ 164
POHL PIOTR, WO PIUK MARCIN, FORMELA PIOTR
“Rigidity of regenerated screw joints in pine wood”......................................................... 170
POHL PIOTR, WO PIUK MARCIN, FORMELA PIOTR
“Investigations on holding ability of screws in regenerated pinewood screw joints”........ 175
POHL PIOTR, RADZIKOWSKI KRZYSZTOF “Investigations on insertion forces
of double-tee joints into solid wood planks and wood-based boards”................................ 180
POLEK-DURAJ KORNELIA “Competitiveness growth comparing to corporate social
responsibility idea on the basis of the timber industry (case study)”.................................. 187
PÓ KA MARZENA, KONECKI MAREK “Analysis of the heat release rate from
wood with applied fire protection by selected flame retardant agents”............................. 192
POPYK W ODZIMIERZ, MIKO AJCZAK EL BIETA, MYDLARZ KATARZYNA
„Innovative Processes in the Polish Wood Industry in the Years 2005 – 2009”................ 196
,
,
“
MDF”............................................................ 201
3
RADOMSKI ANDRZEJ, MA KOWSKI PIOTR, KO CIELNIAK AGNIESZKA
“Determination of Absolute Molar Mass Distribution of Paraloid B72”............................ 206
RADOMSKI ANDRZEJ, ZAWADZKI JANUSZ, DRO D EK MICHA ,
SZADKOWSKI JAN „Non-degrading nitration of pinewood cellulose”........................... 213
ROHANOVÁ ALENA “Characteristic values of quality for spruce timber determined
by MTG Timber Grader device”......................................................................................... 220
ROHANOVÁ ALENA, NUNEZ ERIKA
“Logs and sawn Timber Quality for building constructions”............................................. 225
ROHANOVÁ ALENA, LAGA A RASTISLAV, VACEK VLADIMÍR
“Static and dynamic modulus of spruce structural timber”................................................ 229
ROUSEK MIROSLAV, KOPECKÝ ZDEN K, SVATOŠ MICHAL
“Problems of the quality of wood machining by milling stressing the effect of
parameters of machining on the kind of wood”.................................................................. 233
RÓ A SKA ANNA, SWACZYNA IRENA
“The Construction and Design of a Wicker Furniture Set from the Collection of the
Castle Museum in a cut as a Criterion for Identification”............................................... 243
RÓ A SKA ANNA “Design and Construction Innovation in Wicker Furniture
Created by W adys aw Wo kowski”................................................................................... 248
RUŽINSKÁ EVA, DANIHELOVÁ ANNA, JAB O SKI MAREK, ZBIE MARCIN
“Multi-recovery of specific waste biomass for production environmetally friendly
products. Part 1. Preparation of new type wood materials”............................................... 252
RUŽINSKÁ EVA, DANIHELOVÁ ANNA, MARKOVÁ IVETA,
JAB O SKI MAREK, ZBIE MARCIN “Multi-recovery of specific waste biomass
for production environmetally materials. Part 2. Evaluation selected characteristics of
sulphate waste liquor for their energy utilization”.............................................................. 257
SAFONOV A.O., BELYKH V.V.
“Improvement of Industrial Equipment for Wood Biofuel Production”............................. 261
ŠATANOVÁ ANNA “Monitoring of costs and creation of calculations in business”....... 265
SEDLIA IK JÁN, ŠMIDRIAKOVÁ MÁRIA “Shear strength of the joint
wood – carbon lamella after moisture and heat conditioning”............................................ 270
SEDLIA IKOVÁ MARIANA
“Analysis of the impact of the introduction of the euro in Slovak economy”.................... 275
SEMAK S., MA KOWSKI P., MAZUREK A.
“Whitening of oak wood with hydrogen peroxide”........................................................... 280
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,
“
”........................................... 283
STARECKI ANDRZEJ, JAB O SKI MAREK, DANIHELOVÁ ANNA
RUŽINSKÁ EVA
“Strength properties change in birch veneered high density fiberboard”........................... 288
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SUDO EWA, SULIK PAWE
“Shear strength of glue joints of PVAC adhesives and selected wood species”................ 293
SUJOVÁ ANDREA, SEDLIA IKOVÁ MARIANA
“Forecast of the trend of Slovak Republic economic performance - the basis of
opportunities for future development of enterprises”.......................................................... 298
SWACZYNA IRENA, K DZIERSKI ANDRZEJ, RÓ A SKA ANNA,
SZYMCZYK AGNIESZKA, TOMUSIAK ANDRZEJ, R EWSKA ZOFIA
“Designs of wooden floorings in historical buildings in the Kolbuszowa County”........... 303
SYDOR M., SZULC M., PA UBICKI B.
“Usability of wood-based materials as a supporting layer of PCB”................................... 308
SZCZAWI SKI MIECZYS AW, PACHELSKA HANNA
“Value assessment for deciduous timber (birch, alder) logs for plywood manufacture”... 312
SZCZAWI SKI MIECZYS AW, OLKOWICZ MAGDALENA “The verification
method of the production assortment structure in the furniture factory”........................... 317
SZCZAWI SKI MIECZYS AW, JENCZYK – TO OCZKO IZABELLA
“Application of modified method of beech round wood value pricing”............................ 320
SZCZ SNA MAGDALENA, ANDRES BOGUS AW, KOSTYRA MICHA
“Natural resistance of selected South-East Asian wood species against
Gloeophyllum sepiarium (Wulf. Fr.) P. Karst fungus”....................................................... 327
SZCZ SNA MAGDALENA, GAWRON JAKUB, ZIELENKIEWICZ TOMASZ
“Examination of common ash (Fraxinus excelsior L.) colour change after
heat treatment”.................................................................................................................... 331
SZENTNER KINGA, RATAJCZAK IZABELA, MAZELA BART OMIEJ,
HOCHMA SKA PATRYCJA “Interactions of silicon compounds and mixture of
linseed and tung oils with cellulose „................................................................................. 336
SZWAJKA KRZYSZTOF, ZIELI SKA-SZWAJKA JOANNA
“Interrelationships between cutting force and tool wear in chipboard milling”................. 340
SZWAJKA KRZYSZTOF, ZIELI SKA-SZWAJKA JOANNA “An overview of data
acquisition system for cutting force measuring and optimization in milling”.................... 346
SZYMANOWSKI WAC AW, OLKOWICZ MAGDALENA
“Implementing new products the chance of furniture industry development”.................. 350
SZYMANOWSKI KAROL, GÓRSKI JAROS AW “Influence of the speed machining
to the tool life during processing of the particleboard”...................................................... 355
SZYMA SKI WALDEMAR, PINKOWSKI GRZEGORZ, KRAUSS ANDRZEJ
“Impact of feed speed on the processing quality of seats on a multi-spindle
drilling machine”................................................................................................................ 359
TABERT MAREK, LIS WOJCIECH
“Economic benefits of bio-energy generation from wood waste”..................................... 365
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TOMCZAK A., JELONEK T., RUTKOWSKI M.
“Biometrical characteristics of mature pine stands differing in terms of quality,
growing under site conditions of fresh mixed coniferous forest”....................................... 370
TOMCZAK A., PAZDROWSKI W., JELONEK T.
“Biometrical characteristics of mature pine stands differing in terms of quality,
growing under site conditions of fresh mixed broad-leaved forest”................................... 374
TOMUSIAK ANDRZEJ
“Study on the application of different types of roof trusses in wooden constructions”...... 378
TROCHIMOWICZ ALEKSANDRA
“Conservation of wooden sculpture of saint Anne “.......................................................... 382
TROCHIMOWICZ ALEKSANDRA, SWACZYNA IRENA
“Species of wood used in cradle structures”....................................................................... 386
TULIK MIRELA, RUSIN ALEKSANDRA
“Microfibril orientation during cambial xylem derivatives differentiation in stems of
Scots pine trees grown under polluted environment”......................................................... 390
WALISZEWSKA BOGUS AWA, PR DZY SKI W ODZIMIERZ,
CHADZINIKOLAU TAMARA, SPEK-D WIGA A AGNIESZKA
“Changes in wood basic chemical composition in Salix viminalis in a
model experiment”.............................................................................................................. 395
WALISZEWSKA BOGUS AWA, PR DZY SKI W ODZIMIERZ, KOZ OWSKA
MONIKA, WOJECH RENATA
“Changes in the degree of cellulose polymerisation of Salix viminalis willow seedlings
after supplementation with Cu and Pb”.............................................................................. 401
WARMBIER KRZYSZTOF, WILCZY SKI ARNOLD, DANECKI LESZEK
“Particle size dependent properties of three-layer particleboards with the core layer
made from willow (Salix viminalis)”.................................................................................. 405
WASIELEWSKI ROMAN “Ultimate distortion of circular saw”...................................... 410
WASIELEWSKI ROMAN “Losses and raw material yield of wood sawing processes”.. 414
WASIELEWSKI R., OR OWSKI K., DZURENDA L. „Diagnostic usefulness of
granulometric analyses of chips distribution while sawing of wood”................................ 418
WASIELEWSKI R., OR OWSKI K. A.
“Pro-ecological technology of wood sawing with circular saw blades”............................. 423
WIADEREK IWONA, WALISZEWSKA BOGUS AWA
“Selected mechanical properties of one-year old twigs of Salix acutifolia”....................... 427
WIELOCH GRZEGORZ, OSAJDA MARCIN, JAVOREK LUBOMIR
ZASADA MAREK, CIELOSZYK JANUSZ, CHMIELEWSKI KRZYSZTOF
“New idea in construction and performance of turning rotary knife”................................ 433
WIELOCH GRZEGORZ, PORANKIEWICZ BOLES AW “Computerised production
line of carpentry products – processing centre Hundegger K-2”........................................ 438
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WIELOCH GRZEGORZ “The treehouse “........................................................................ 444
WIERUSZEWSKI MAREK., GOTYCH VIKTOR., HRUZIK GINTER J.,
MARCINKOWSKA AGNIESZKA, KRYSTOFIAK TOMASZ, LIS BARBARA
“Comparison of traits pine timber used in skeletal constructions”..................................... 448
WIERUSZEWSKI MAREK, GOTYCH VIKTOR, HRUZIK GINTER J.,
GO U SKI GRZEGORZ „Glued elements for construction”.......................................... 453
WIERZBOWSKI M., BARA SKI J,
“Application of gas-steam mixture for wood drying purposes”.......................................... 458
WILKOWSKI JACEK, DUBIS MICHA , CZARNIAK PAWE
“Influence of cutting speed on tool life during of laminated particleboard drilling”.......... 463
WILKOWSKI JACEK, ZIELI SKI JANUSZ, CZARNIAK PAWE
“Analysis of tool life criterion during laminated chipboard milling”................................. 468
WILKOWSKI JACEK, EREBIEC BART OMIEJ, CZARNIAK PAWE
“Analysis of surface roughness in wood milling”.............................................................. 474
WILKOWSKI JACEK, GRZE KIEWICZ MAREK, CZARNIAK PAWE ,
LITWA MICHA
“Influence of wood thermal modification on cutting resistance during drilling”............... 480
WITOMSKI PIOTR, KRAJEWSKI ADAM, NAROJEK TADEUSZ
“Measurements of wood density using X-ray computer tomography”.............................. 485
WO PIUK MARCIN, POHL PIOTR “Investigations on geometry of locally
modified area in MDF boards by a non-destructive method”............................................ 490
ZABIELSKA-MATEJUK JADWIGA, PERNAK JULIUSZ, STANGIERSKA ANNA
“The resistance of Scots pine wood protected with ammonium ionic liquids to attack
by mould fungi”.................................................................................................................. 497
ZAWADZKI JANUSZ, ZIELENKIEWICZ TOMASZ, RADOMSKI ANDRZEJ
“Migrations of chromium compound in pine wood samples (Pinus sylvestris L.)”........... 502
ZEMIAR, J., PETRÍK, J., GAFF, M.
„The change of veneer thickness after pressing – compression”....................................... 509
ZIELENKIEWICZ TOMASZ “Method development of the XRF analysis of metals
contents in scots pine wood (Pinus sylvestris L.)”............................................................. 514
ZIELI SKA-SZWAJKA JOANNA, GÓRSKI JAROS AW, SZWAJKA KRZYSZTOF
“Measuring components cutting force in chipboards milling”........................................... 522
ZIELI SKA-SZWAJKA JOANNA, GÓRSKI JAROS AW
“Schnittgeschwindigkeitseinfluß auf die Standzeit den Fräser”......................................... 527
“
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PRZYBYSZ PIOTR, PRZYBYSZ KAZIMIERZ
“Prospects of papermaking industry development in Poland – barrier of wood supply”... 536
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Board of reviewers:
Prof. dr hab. Bogus aw Bajkowski
Prof. dr hab. Piotr Beer
Dr hab. Ewa Dobrowolska
Prof. dr hab. Jaros aw Górski
Prof. dr hab. Adam Krajewski
Prof. dr hab. Krzysztof Krajewski
Prof. dr hab. Donata Krutul
Dr hab. S awomir Krzosek
Dr hab. Hanna Pachelska
Prof. dr hab. Andrzej Starecki
Prof. dr hab. Irena Swaczyna
Prof. dr hab. Wac aw Szymanowski
Dr hab. Piotr Witomski
Dr hab. Janusz Zawadzki
Dofinansowano ze Ğrodków Ministra Nauki i Szkolnictwa WyĪszego
Polska Akademia Nauk Komitet Technologii Drewna
WARSAW UNIVERSITY
OF LIFE SCIENCES PRESS
e-mail: [email protected]
ISSN 1898-5912
SERIES EDITOR
Ewa Dobrowolska
Marcin Zbie
PRINT: ZPW POZKAL
Annals of Warsaw University of Life Sciences – SGGW
Forestry and Wood Technology No 72, 2010: 9-12
(Ann. WULS-SGGW, For and Wood Technol. 72, 2010)
Studies concerning the chip formation at the longitudinal drilling of the
beech wood with help high speed camera
S. M. BARBU1, L.A.M.BADESCU2, L. JAVOREK3
1,2
1,2
Wood Machining Center of Excellence, Transilvania University of Brasov, Romania
Department of woodworking machines and equipments, Faculty of Environmental and Manufacturing
Technology, Technical University in Zvolen, T.G. Masaryka 24, 960 53 Zvolen, Slovakia
3
Abstract: Studies concerning the chip formation at the longitudinal drilling of the beech wood with help high
speed camera. The paper presents an important data basis concerning the chip formation at the longitudinal
drilling of the beech wood in longitudinal section with the direction of fiber of 0o, 30 o, 45 o and 60 o using helical
drills with diameter of 8mm. Images recorded with high speed camera were processed and the results obtained
from the researches have been analyzed and discussed.
Keywords: chip formation, chip shape, beech, high speed camera, helical drill
INTRODUCTION
The study for chip formation at wood drilling present a special importance for processing
analysis and require thorough research. This paper present some from results obtained in
based on some research concerning this issue. For analysis, the authors of this paper have
discussed about the chip formation at longitudinal drilling of beech wood with drill of 8mm.
THE EXPERIMENT
Experimental researches were made on a milling machine FSU-22. For make holes it was
used a helical drill plated with CMS with cylindrical shaft flattened with diameter of 8 mm,
with two channels, the peak angle of 2 = 600 and angle of inclination of the propeller =
130.
After checking the working parameters on each sample who was cutting in longitudinal
section with direction of bending fiber of 0o, 30 o, 45 o and 60 o from beech timber with
humidity of 8-12% and dimension of L x l x g = 195 x 40 x 37 [mm x mm x mm] were made
five holes with drilling depth of 30 mm.
Experiments were made on these work conditions: speeds ranging between 110 and 345
rot/min and feed speeds between 80 and 250 mm/min.
The study concerning chip formation at drilling wood of beech was made using high
speed camera Inline Model 250, connected to the computer, which reached speeds record of
60, 125 and 250 frames per second. Before making recordings it was adjusted the image,
digital brightness of image, recording speed (60 frames per second) and camera resolution.
Recorded files were saved with RAW extension, and then were viewed and analyzed using
the PAC application player.
For chip analysis it was used an stereomicroscope STEMI 2000C Zeiss with digital
camera embedded type Canon Power Shot G9, cold light source type KL 2500 LCD and
Axiovision software with which we made the acquisition and processing images obtained
(with camera).
Was positioned the chips which were obtained after processing through drills, on the
microscope table, and then were set: the stereomicroscope objective at 0.65 x to enlarge and
brightness of the light source to obtain a clear picture. Images obtained with the digital
camera were saved, processed, analyzed and discussed.
RESULTS
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Some between results obtained concerning chips formation during the process of longitudinal
drilling of wood are presented in figure Fig. 1. and Fig. 2.
Lu-h
Lu
Lu-h1
Lu-h3
Lu-h2
Fig. 1. Sequences shooting at longitudinal drilling having direction of bending fiber of 300, speed n = 220
rot/min, feed speed u = 250 mm / min, hole 3 (chip shape detached)
Lu
Lu-h1
Lu-h3
Lu-h2
10
Lu-h4
Lu-h
Fig. 2. Sequences shooting at longitudinal drilling having direction of bending fiber of 600, speed n = 220
rot/min, feed speed u = 250 mm / min, hole 2 (chip shape detached)
The chip shape obtained at wood drilling is shown in figure Fig.3.
a
b
c
d
e
f
Fig. 3. The chip shape at longitudinal drilling of beech wood with blend fiber direction 45o, speed n = 110
rot/min, feed speed u = 80 mm / min, hole 3: (a) chips obtained during process; (b, e , f) chips of medium size
(c) small chips (d) chips obtained through chips agglomeration on drill channel.
DISCUSSION AND CONCLUSION
Analyzing the formation process of chips to the longitudinal drilling wood we can observed:
¾ During execution of holes, the chips which are formed at entry of drilling in wood
material are small dimensions. (Fig. 3c) These types of chips allow easy evacuation due to
a relatively short path which they crossing up to their elimination.
¾ As the drill advancing is formed the heat generated by consuming mechanical work in the
cutting process. Sometimes, the heat produced during the cutting process leads to: burning
wood because of friction between tool and workpiece (Fig. 3d), increased wear and
decreased ability of cutting tool.
¾ Chips formed (Fig. 3.d) during the drilling process, after a while at the end of hole, the
chips can't be discharge efficiently, this choke drill channels on a part owing to tool
11
geometry, on the other hand inadequate regimens. As the drill out from wood, the chips
are detached from the drill channel and fall, while in other cases they remain on the drill
channels depending on their size and structure of wood.
¾ The chip shape depends on: the characteristics of the material of processing, the working
parameters of the drill, geometry and tool wear.
REFERENCES
1. L.A.M. BADESCU, Modelarea si optimizarea proceselor prin aschierea lemnului, Ed
Info-market Brasov, 2001, ISBN 973-8204-07-0.
2. L.A.M. BADESCU, S.M. BARBU, Aspecte privind defectele care apar la burghierea
strapunsa a panourilor pe baza de lemn cu burghie elicoidale si burghie cu varf de
centrare si dinti trasori, Conferinta Nationala Stiinta si Ingineria Lemnului in Mileniul
III,vol. I, editia a VI-a, 4-6 noiembrie 2005, Brasov, 2005, ISBN 973-635-599-3,
pp.251-258.
3. V. DOGARU, Aschierea lemnului si scule aschietoare, Editura Didactica si
Pedagogica, Bucuresti, 1981.
4. G. E. Woodson, C. W. McMillin, Boring Deep in Southern Pine, Forest Products
Journal, vol. 22, no.4, 1972, pp. 49-53.
5. C. W. McMillin, G. E. Woodson, Moisture Content of Southern Pine as Related To
Thrust, Torque, and Chip Formation, Forest Products Journal, vol. 22, no.11, 1972, pp.
55-59.
Streszczenie: Tworzenie siĊ wióra przy wzdáuĪnym wierceniu drewna buka. Praca prezentuje
tworzenie si wióra przy wierceniu drewna bukowego pod k tem 0o, 30o, 45o oraz 60 o do
w ókien, przy u yciu wiert a rubowego 8mm. Obrazy otrzymane kamer poklatkow
zosta y obrobione, poddane analizie oraz omówione.
Corresponding author:
Eng. Simona-Maria BARBU
Transylvania University of Brasov, 29 B-dul Eroilor, Brasov, Romania
E-mail address: [email protected] (Simona-Maria BARBU)
Prof. Dr. Eng. Loredana Anne-Marie BADESCU
Transylvania University of Brasov, 29 B-dul Eroilor, Brasov, Romania
E-mail address: [email protected] (Loredana Anne-Marie BADESCU)
Assoc. prof. ubomír Javorek, PhD.
Department of Woodworking Machines and Equipment, Technical University in Zvolen
T. G. Masaryka 24, SK - 960 53 Zvolen, E-mail address: [email protected]
Computational method for determining the static stiffness of the saw blade
K. DUCHNICZ, R. WASIELEWSKI
Department of Manufacturing Engineering and Automation, Mechanical Engineering Faculty,
Gdansk University of Technology.
Abstract: Computational method for determining the static stiffness of the saw blade. This article describes how
modeling and calculation of stress and strain of the saw blade with a complex body geometry using computer
programs aided for design.
Keywords: wood cutting, circular sawing machine
INTRODUCTION
Static stiffness of saw blades is one of the key factors determining the effects of
cutting. Its knowledge is therefore essential both at the design stage saws, as well as at the
stage of its operation.
The difficult construction of the saw blade resulting from different kinds of shapes,
sizes and quantities: chip grooves, as well as notch: compensating, cooling, soundproofing
and scrapers causes to determine the saw blade stiffness of the most used experimental
methods [Wasielewski]. These methods are simple and precise and therefore readily applied.
But the main drawback of this method is that we have a real saw.
At the stage of analysis, for example, the impact of saw blade construction and its
attachment to the stiffness, however, is more useful computational method for determining the
static stiffness of a saw blade. The complex construction of saw blade makes, however, that
theoretical designation the static stiffness is possible only using numerical methods.
SAW BLADE MODELING
For the numerical calculations was used saw blade model created in ProEngineer
[DUCHNICZ]. During modeling aplied several simplifications:
saw blade has a uniform thickness throughout the cross section (not included thicker
blades and knives, scrapers),
saw blade shall be made of the same material (not considered into account that the
scraper blades and knives are made of cemented carbide),
saw blade attachment is via: collars (fig. 1a) (does not take into consideration the
manufacturing deviation of collars), or take of the six degrees of freedom on the
outside diameter of collars (fig. 1b).
13
a)
b)
Fig. 1. Attachment of the saw blade: a) with collars, b) with take of the six degrees of freedom on the outside
diameter of collars
The purpose of this simplification is to minimize the need for high processing power
of computer, where one of the reasons is advanced stage and the number of geometric features
considering example.
CALCULATION OF THE VALUE OF STRESS AND STRAIN
To determine the values of stress and strain or displacement saw blades use a
commercial computer program ANSYS, which used for finite element method calculations.
In this program, defined the basic parameters of the saw blades material properties
such as Young's modulus, Poisson's number and density. Next, was chosen structural model
and defined the element mesh size divide. Next, model divided into finite elements fig. 2a and
defined the boundary conditions such as fixed support and the load. The force value loading
the saw blade adopted a value of F = 50N. This force implemented to the edge of the blades in
the direction of the axis of rotation in the form of two parallel vectors each 25N, separated by
a few millimeters fig. 2b. This load eliminates the relatively large, very often the maximum
strain and stress, which could be undesirable, and thus cause an error of calculation. The
effect of incorrect loading of a saw blade resulting from the implementation of a concentrated
force to the blade shown in fig 2c. In this picture showing stress concentration at the applied
force.
An example of the effects of stress and strain calculations of the saw blade shown in Figure 3.
The presented method of presentation of calculation results and visualization of stress and
strain or displacement of the body, allows not only determine their value in a certain points,
but more importantly shows the size and extent of stress and strain of saw blade body.
14
a)
b)
c)
Fig. 2. Modeling of saw blade: a) divide of finite elements, b) loading the blade, c) effect of stress calculation, in
the case concentrated force loading
a)
b)
Fig. 3. Results of the calculations in the form of visualization: a) displacement, b) stress
Due to the specific construction of a saw blades, which one of the dimensions is much
smaller than the other, modeling of saw blade geometry was carried out using two types of
structural models: the first is the solid model and the second is the shell model. The first
model have eight-node elements were built in the shape of cubes, while the second model
have eight-node element in the shape of squares. The calculations of the same saw blades with
both structural models showed that both models can be used. The difference between the
values of strain for both structural models is approximately few percent.
The low stiffness of saw blade allow also simplify the modeling of the saw attachment, which
can be limited to receive six degrees of freedom on the outer diameter of collars. Comparative
calculations performed for the same saw blades mounted in the clamping collars (fig. 1a) and
without collars (fig. 1b) showed displacement differences a few percent.
15
SUMMARY
Presented an algorithm to create the structural model and model to calculating with using the
commercial ANSYS computer program used for numerical calculations by finite element
method enables the determination of deformation, stress and stiffness of saw blades with
difficult body geometry for which it is impossible to perform analytical calculations. In
addition, conducted numerical calculations, it possible to 3D visualize the results of
calculations which significantly simplifies their interpretation.
REFERENCES
1. R. WASIELEWSKI, Static stiffness of circular saw. Annals of Warsaw University of Life
Sciences - SGGW. Forestry and Wood Technology. 69 (2009) 393-396.
2. K. DUCHNICZ, Minimalizacja b dów mocowania pi na dwuwrzecionowej przecinarce
tarczowej. Praca dyplomowa, promotor R. Wasielewski. Politechnika Gda ska, Wydzia
Mechaniczny, masz. Gda sk 2010.
Streszczenie: Obliczeniowa metoda wyznaczania sztywnoĞci statycznej piáy tarczowej. W
niniejszym artykule opisano sposób modelowania i oblicze odkszta ce i napr e pi
tarczowych o z o onej geometrii korpusu z wykorzystaniem komputerowych programów
wspomagaj cych projektowanie.
Department of Manufacturing Engineering and Automation, Mechanical Engineering Faculty, Gdansk
University of Technology, Narutowicza 11/12, 80-952 Gda sk, Poland
E-mail address: [email protected] (Roman Wasielewski)
Effect of the saw blade geometry at its static stiffness
K. DUCHNICZ, R. WASIELEWSKI
Gdansk University of Technology.
Abstract: Effect of the saw blade geometry at its static stiffness. This article describes the impact of selected saw
blade parameters significant effect on the static stiffness
INTRODUCTION
Static stiffness of each element depends on its shape (geometry), method of
attachment and the material properties, that it is made. Parameters of saw blade, which have a
decisive impact on the value of stiffness are:
- diameter of the saw Dz,
- diameter of the collars Dt,
- thickness of the saw b,
- geometry of the saw blade (quantity, shape and size of chips grooves, as well as
notch: compensating cooling, soundproofing, scrapers)
- the attachment method of saw blades,
- type of material and stress of saw blade.
Because, on the value of static stiffness of the saw blade are affected by many factors,
it is difficult to formulate detailed formulas on the quantitative impact of individual factors for
a saw blade. However, based on examples showing the effects of selected parameters for
specific saw blades can be formulated as a series of general recommendations concerning the
qualitative impact of selected parameters of the static stiffness of saw blades.
EFFECT OF SELECTED PARAMETERS ON SAW BLADE STIFFNESS
Effect of basic parameters on the saw blade stiffness, such as: diameter Dz, thickness b
or diameter of collars Dt, is generally known in quality range. In terms of quantities, because
of the complexity of the construction of a saw, however, requires testing.
Apart from these basic parameters, a significant impact on the stiffness of the saw
blade has a geometry of the saw blade body. This is shown by the results of experimental
studies [WASIELEWSKI]. Each notch reduces stiffness of cutting edge which are in their
vicinity. An interesting example of the effect of geometry on the stiffness of the saw blade
shown in Figure 1. Two deep notch into the body of the saw blade (fig. 1a) resulted in a
decrease in the stiffness of the blades, not only in the vicinity of these notch (blade No. 6 and
16) (first two numbers of blades shown in fig. 1a), but also blades situated that are central part
of the notch (blade No. 2 and 12). The reason is that the load of these blades causes the
deformation of the entire segment saw blade.
17
a)
b)
0,16
2
1
0,12
k, N/mm
Dz = 225,
Dt = 125,
b = 2,2
0,08
0,04
19
17
15
13
9
11
7
5
3
1
0,00
Fig. 1. Stiffness k of the saw blade for each edge
For the saw blade, in addition to the geometry of the body, an important parameter is
also the size of the chips grooves located near the edges. Effect size of the grooves on the saw
blade stiffness is shown in the calculation example edge deflection of the saw blade, which
are differ only in size and shape of notch grooves (fig. 2a, b). The calculations were
performed for saw blades with a thickness of b = 2.54 mm and a diameter of collars Dt = 105,
125 and 160 mm, which corresponds to the difference of diameters Dz-Dt = 195, 175 and 140
mm [DUCHNICZ].
35
0
Dz
=
53
28
Dz
28
53
Dt
Dz
53
35
Dt
Dt
5
1
c)
=
30
0
b)
=
30
0
a)
5
5
1
1
Fig. 2. Saw blades taken for calculations
The values of corner deformation f edges 1 and 5 (fig. 2), loaded with a force Fp =
50N, shown in Figure 3. As you can see the change in shape, and above all reduce the
quantity of chip grooves in a saw blade from Figure 2b reduces edges deflection and thus
increase their stiffness.
18
b)
0,8
0,8
0,7
0,7
0,6
0,6
0,5
0,5
f [mm]
f [mm]
a)
0,4
0,4
0,3
2a
0,3
2a
0,2
2b
0,2
2b
0,1
2c
0,1
2c
0
140
150
160
170
180
190
0
140
200
Dz-Dt [mm]
150
160
170
180
190
200
Dz-Dt [mm]
Fig. 3. Deformation f edges corner: a) No. 1, b)No. 5, saw blades from fig. 2
Effect size of the chip grooves can be seen clearly in the example in Figure 4, which
shows the results of deformation calculations of the saw blade in Figure 2a for Dt = 105 mm
and circular disc in the same way loaded and mounted. Deflection of the saw blade without
grooves is two times smaller than the saw blade, with them.
a)
b)
Fig. 4. Deformation of the saw blade : a) with chip grooves, b) without chip grooves
For the saw blade is also an important parameter of the difference in saw blade
diameter and the collar diameter Dz-Dt. On Figure 3 also compared deformation of two saw
blades with the same shape and size of the grooves, however, with different outer diameter
(fig. 2b, c), while retaining the same difference diameter Dz-Dt = 195, 175 and 140 mm. As
you can see deformation of these two saw blades are very similar. Local character of
deformation of the saw blade makes, on the the blade deformation do not affect the absolute
values of external diameter of saw blade Dz and the diameter of collars Dt, therefore
difference in these diameters Dz-Dt.
19
SUMMARY
The results of experimental studies and numerical calculations show that the static
stiffness of a saw blade depend on a significant many saw blade parameters. Knowledge of
their effect on the saw blade stiffness can be used both in the design process, as well as
operating the saw blade.
REFERENCES
1. R. WASIELEWSKI, Static stiffness of circular saw. Annals of Warsaw University of Life
Sciences - SGGW. Forestry and Wood Technology. 69 (2009) 393-396.
2. K. DUCHNICZ, Minimalizacja b dów mocowania pi na dwuwrzecionowej przecinarce
tarczowej. Praca dyplomowa, promotor R. Wasielewski. Politechnika Gda ska, Wydzia
Mechaniczny, masz. Gda sk 2010.
Streszczenie: Wpáyw geometrii piáy tarczowej na jej sztywnoĞü statyczną. W niniejszym
artykule opisano wp yw wybranych parametrów pi y tarczowej wp ywaj cych w istotny
sposób na jej sztywno statyczn
Evaluation of the design impact on the performance of polish
furniture enterprises
BEATA FABISIAK, STANIS AW DZI GIELEWSKI
Department of Furniture Design , Poznan University of Life Sciences
Abstract: Evaluation of the design impact on the performance of polish furniture enterprises. The aim of the
study was to describe the main benefits associated with investing in design. The results of survey conducted
among 75 furniture manufacturing companies were presented. The obtained data was elaborated taking into
account the size of the given company. Moreover much attention was paid to the evaluation of design impact on
business performance of analyzed enterprises.
Keywords: design, furniture manufacturing, benefits of investing in design
INTRODUCTION
Design plays in increasingly important role in activities of enterprises operating in the
economies of highly developed countries. Design was demonstrated to be particularly
important in the case of enterprises manufacturing consumer goods, among others, furniture,
i.e. companies oriented towards constant improvement of the design value of the offered
articles (Edman 2004, Report DTI 2005, Tether 2005). Therefore, the opinion that investment
in design can have a positive impact on the operation and development of enterprises is
becoming increasingly widespread.
The aim of this article was to analyze advantages resulting from investment in design
and to assess its impact on the activities of selected Polish enterprises involved in furniture
production. Special attention was focused on possibilities of development and improvement
of the situation of a given company on the market thanks to the application of design.
The performed investigations comprised economical subjects located in Poland
specializing in furniture production. The enterprises studied were selected on the basis of the
quota sampling method, taking into account the level of employment and geographic
localisation so that the firms well represented the structure of furniture industry in Poland.
The performed analyses included data from 75 enterprises.
RESULTS AND DISCUSSION
The first step in the analysis of the design impact on the furniture designing process
and production involved determination of the significance of design as a factor affecting the
development of enterprises functioning in the furniture sector. Up to 92% of the examined
companies were of the opinion that design exerts influence on the operational development of
enterprises manufacturing furniture (the answers “rather yes” and “definitely yes”(Fig. 1).
21
Does design play an important role in the development
of furniture manufacturing companies?
definitely yes
rather yes
rather no
definitely no
it's difficult to say
0
10
20
30
40
50
60
70
Percentage of enterprises (%)
Fig. 1. Opinion structure of the managers of the examined furniture enterprises regarding the role of design in the
development of furniture manufacturing companies
Source: Own elaboration based on the performed empirical research
Using the method of statistical grouping, detailed analyses of correlations between the
size of an enterprise and assessment of design as a factor determining the development of
companies in the furniture sector were performed. It was found that only micro- and smallsized enterprises expressed doubts as to the importance of the role of design actions in the
process of furniture production (Fig. 2). However, it should be emphasized that it was a very
small group of enterprises. Great majority of even very small companies considered design an
important tool preconditioning the development of furniture industry. High role of designing
in the analyzed sector of economy was also confirmed by the fact that 100% of both large and
medium-sized enterprises (total of replies: “rather yes” and ”definitely yes”) considered
design as a factor affecting development of the branch. Producers who took part in the survey
expressed the opinion that design makes it possible for the company to build an image that is
both strong and recognizable on the marketplace which, in turn, is associated with its prestige.
Numerous respondents emphasized the fact that thanks to design, the company is capable of
manufacturing better products. At the same time, higher added value of the offered articles
increases considerably possibilities of their sale.
80
70
60
micro-enterprises
small enterprises
medium enterprises
big enterprises
50
40
30
20
10
0
definitely no
rather no
rather yes
definitely yes
Does design play an important role in the development of furniture manufacturing companies?
Fig. 2. Opinion structure of the managers of the examined furniture enterprises regarding the role of design in the
development of furniture manufacturing companies depending on the size of the enterprise
22
According to the questioned entrepreneurs, furniture must be liked or rather it should
captivate and enrapture potential users. In the first phase of the purchasing process, customers
pay attention, primarily, to visual aspects of a piece of furniture. Nevertheless, manufacturers
strongly emphasized that in good furniture design, it is not only the external form that counts
but other additional factors that customers discover in the course of furniture utilization are
equally important. Good design allows integration, in a single article, of both aesthetic
external form as well as material and construction novelties resulting in a product
characterized by unique added value. In addition, design is also important for the
development of furniture sector because in a well-designed article considerable attention is
also paid to ergonomics. In the opinion of the examined entrepreneurs, changes taking place
on the marketplace in this area, i.e. offering of products intended for consumers who are
increasingly aware of the influence of utilized furniture on human health, can contribute to the
improvement of living standards of consumers. Additionally, it was also stressed that
novelties introduced into new articles, continuous development and monitoring of changes
taking place on the market, are all significant. It was emphasized that in West European
countries, on average, companies develop new collections every two years. The surveyed
manufactures stressed that more and more frequently, Polish consumers know world design
trends and look for furniture which follows these trends. Consequently, attention to high
design quality of offered articles results in a steady development of enterprises and, as
confirmed by the performed investigations, the above tendency is quite visible in the case of
the furniture sector.
Within the framework of the performed experiments, opinions of entrepreneurs
regarding the impact of design on the development of their companies were also analyzed. It
turned out that more than 80% of respondents indicated that they expected that investment in
design would improve the situation of their enterprises on the market (Fig. 3) and only 9% of
producers presented a different opinion. However, it should be added that this group included
subcontractors manufacturing furniture according to models commissioned by ordering
enterprises. It can be assumed that these factories could not ‘consume’ advantages resulting
from the introduction of new design at the same level as companies designing and marketing
their own articles.
45
40
35
30
25
20
15
10
5
0
definitely no
rather no
rather yes
definitely yes
Will investing in design improve the situation of your company on the marketplace?
Fig. 3. Structure of the opinion of the surveyed furniture manufacturers regarding the impact of design on the
improvement in the situation of their enterprises on the marketplace depending on the size of company
The performed analysis of the assessment of the design influence on the improvement of a
given company’s situation on the market depending on its size revealed that none of the
examined micro-enterprises was convinced as to the rightness of the discussed dependence.
23
Nevertheless, up to 67% of them presumed that investment in design may exert a positive
influence on their activities (Fig. 4). The expressed reservations may have resulted from
poorly developed tools and procedures facilitating the use of designing in Poland for small
economical subjects. It is, therefore, difficult for these enterprises to get involved in designing
activities and achieve profits. There are special governmental programs in many countries in
the world the aim of which is to support design development and encourage micro-, smalland medium-sized enterprises to introduce designing programs (Salimäki i in. 2004, Design
Denmark 2007, Report Creating a competitive edge through design. Better by Design 2008).
70
60
50
micro-enterprises
small enterprises
medium enterprises
big enterprises
40
30
20
10
0
definitely no
rather no
rather yes
definitely yes
Will investing in design improve the situation of your company on the marketplace?
Fig. 4. Structure of the opinion of the surveyed furniture manufacturers regarding the impact of design on the
improvement in the situation of their enterprises on the marketplace depending on the size of company
When assessing the impact of design on the improvement of a given enterprise
situation on the market, it was strongly emphasized that high design level was usually
associated in the minds of consumers with the company’s reliability and stability. There
seems to be no doubt that there is a direct relationship between the offering of nicely-designed
articles and positive perception of an enterprise. Furniture manufacturers associated a positive
impact of investment in design with the possibility of development of better products which
such investment created and which were easier to promote and sell. In addition, the designed
new models caused that such enterprises were more noticeable on the marketplace and were
able to distinguish themselves among competing companies. It was further observed that a
new design and product gave companies potential chances of expanding already captured
markets and, consequently, of development. It was emphasized that, in modern-day economy,
design is no longer an optional tool but is becoming more and more a necessity without
which, an enterprise will be pushed out of the marketplace.
The performed investigations revealed that the range of benefits resulting from the
design application by furniture enterprises is wide (Fig. 5). The largest group of companies
(nearly 80%) indicated that design contributed to improvement of competitiveness, increase
of sales (67%) and increase of profits (54%). Moreover, furniture manufacturers emphasized
the possibility (thanks to application of design) of the company image improvement (49%),
products distinguishing (47%) as well as expansion into new markets (42%). For the surveyed
entrepreneurs, the existence of tangible advantages resulting from investments in design was a
very serious issue, especially when they were undertaking strategic decisions associated with
the expansion of activities of a given unit.
24
90
80
70
60
50
40
30
20
10
ss
ve
ne
St
re
ng
t
re
as
e
of
s
tit
i
om
pe
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c
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fc
m
en
Im
pr
ov
e
al
es
In
le
cr
ve
Th
ea
l
e
he
se
po
n
of
ss
o
fc
pr
ib
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of
om
its
y
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of
ny
di
e
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po
’s
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im
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ib
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du
in
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In
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cr
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ea
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e
ar
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in
ts
ib
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ilit
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In
y
ke
cr
of
e
ts
as
w
h
id
e
ar
en
in
e
in
ex
Im
g
po
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th
ov
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rt
ra
em
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ve
ng
en
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of
fp
pr
r
o
I
o
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du
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ct
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ro
ct
s
po
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m
nc
en
ib
tio
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ity
ov
ro
en
du
em
ha
ct
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al
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th
ro
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od
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uc
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at
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io
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ity
0
Fig. 5. Benefits resulting from the application of design in the examined furniture enterprises
SUMMARY
Recapitulating, it should be emphasized that majority (92%) of managers in the
examined enterprises was convinced that the application of design exerted a positive influence
on the development of furniture manufacturing companies. During the analyzed period of
time, advantages associated with investment in design were noticeable more clearly in large
and medium-sized enterprises. The recorded smaller proportions of micro- and small-sized
companies convinced about the impact of design on the improvement of their situation on the
market resulted, first and foremost, from small possibilities of investment into design
activities but also from insufficiently developed programs of design support or their small
popularity among furniture manufacturers. Nevertheless, it is worth emphasizing that even
micro- and small-sized enterprises understand the necessity of investment in the development
of new products and express opinion that these types of activities may contribute to the
expansion of their activities. This fact was also confirmed by the analysis of advantages
resulting from the application of design which showed that in this field the examined Polish
furniture companies clearly recorded advantages associated with the improvement of
competitiveness not only of individual products but also of the entire company. Production of
well-designed articles increased, among others, possibilities of their sales making it possible
for these enterprises to achieve higher profits from their activities.
REFERENCES:
Design Denmark (2007): The Danish Government, Denmark.
Edman R. (2004): Swedish companies on design-Attitudes, profitability and design maturity
in Swedish companies, conference proceedings: Helsinki Design Summit,1-2 September.
Report Creating a competitive edge through design. Better by Design (2008): New Zealand
Trade and Enterprise, Auckland, New Zealand.
Report DTI (2005): Creativity, Design and Business Performance, DTI Economics Paper No.
15, November.
25
Salimäki M., Ainamo A., Salmenhaara K. (2004): Country report: The Finnish design
industry, prepared for the research project: The Future in Design, the competitiveness and
industrial dynamics of the Nordic design industry, Helsinki School of Economics.
Tether B. (2005): The Role of Design in Business Performance, Department of Trade and
Industry, Great Britain.
Streszczenie: Ocena wpáywu designu na dziaáalnoĞü polskich przedsiĊbiorstw meblarskich.
Celem artyku u jest analiza korzy ci wynikaj cych z inwestowania we wzornictwo oraz ocena
jego wp ywu na dzia alno wybranych polskich przedsi biorstw zajmuj cych si produkcj
mebli. Przedstawiono wyniki bada przeprowadzonych w ród 75 przedsi biorstw
meblarskich zlokalizowanych na terenie Polski. Szczególna uwaga zosta a zwrócona przede
wszystkim na mo liwo rozwoju i poprawy sytuacji przedsi biorstwa na rynku dzi ki
stosowaniu wzornictwa.
Poznan University of Life Sciences, Department of Furniture Design
ul. Wojska Polskiego 28, 60-637 Poznan, Poland
Beata Fabisiak
E-mail: [email protected]
Stanis aw Dziegielewski
Properties of thermally modified ash wood (Fraxinus americana) in the
aspect of its affinity to water
WALDEMAR MOLI SKI, EWA FABISIAK, TOMASZ SZWABA
Department of Wood Science, Poznan University of Life Sciences
Abstract: Properties of thermally modified ash wood (Fraxinus americana) in the aspect of its affinity to water.
The paper reports on the changes in the hygroscopic equilibrium of ash wood after thermal modification at
different values of the relative air humidity and the degree of the wood swelling in transversal directions. It is
shown that in the range of molecular sorption the thermal modification of wood causes a greater reduction in its
hygroscopicity than in the range of capillary sorption. The reduction in the degree of wood swelling is also found
greater in the tangent direction than in the radial one. The reduced swelling of the thermally modified wood is
directly related to its decreased hygroscopicity with respect to that of unmodified wood.
Keywords: Ash wood, thermal modification, equilibrium moisture content, swelling
INTRODUCTION
Recently, increased interest has been observed in thermal modification of wood. It has
been prompted by ecological character of this type of modification and the high quality of the
final product that is characterised by reduced hygroscopicity, improved size stability and
resistance to biotic decomposition. Moreover, thermal modification gives wood of attractive
dark colour that can successfully imitate that of exotic wood (upon specific programme of
modification) (Hill 2006, Akyildiz & Ates, 2008). Thermal modification eliminates the
imperfections of the natural wood colour. From among many known and applied on industrial
scale processes of thermal wood modification, particularly attractive is that developed in
Finland (ThermoWood®Handbook, Finnish Thermowood Association, Helsinki 2003).
According to Boonstr (2008), the interest in thermal treatment of wood follows also from the
need to inhibition of excessive exploitation of wood of desired technological properties
coming from tropical forests and from restrictions on the use of toxic chemicals for
modification of wood from trees of European species.
The positive effect of thermal treatment on reduction of wood hygroscopic character
has been already known (e.g. Kollmann & Shneider 1963). According to Kollmann & Fengel
(1965) the limit temperature of wood treatment causing reduction in its hygroscopicity
depends on the species of wood. For example for pine wood it is as low as 100°C, while for
oak wood it is 130-150°C. Popper et al. (2005) analysed sorption isotherms recorded for five
species of wood modified at 100, 150 and 200qC and a control sample and reported that
reduction in the wood sorption abilities is noted already after its preliminary heating at 100qC,
whereas significant differences appear for wood modified in higher temperatures. The
analysis of isotherms within the Hailwood-Horrobin model has shown that the changes take
place in the range of chemisorption and in that of capillary sorption. The reduced
hygroscopicity of thermally modified wood and its reduced moisture-caused deformations
follow from the reduction of hydroxyl groups in wood substance, related mainly to
decomposition of hemicelluloses, relative increase in the crystallinity of cellulose and partial
degradation and cross linking of lignin (Boonstra et al. 2007, Windeisen et al. 2009). Many
authors have indicated that the affinity of thermally modified wood to water depends not only
on the parameters of modification but also on the wood species.
This study was undertaken to determine the equilibrium moisture content at different
relative air humidities, maximum swelling in transversal directions in wood from American
ash (Fraxinus americana) subjected to thermal modification according to the method
27
developed in Finland. This paper presents part of the results obtained at the Department of
Wood Science, at Poznan University of Life Sciences.
METHODS
The experiment was performed on 4 trimmed boards of 25 mm in thickness and 100
cm in length, in which the annual rings were tangent to its broader surface. Each board was
divided into two parts, of which the shorter one was about 350 mm long. The parts were
marked to be able to identify them. The longer parts were subjected to modification, while the
shorter ones were treated as controls. The process of modification was carried out according
to the procedure described in ThermoWood®Handbook, Finnish Thermowood Association,
Helsinki 2003, at 190 or 200°C for 2 hours. After modification and conditioning in the open
space, the slabs were cut out of the boards and planned to the cross section of 20x20mm.
Analogous slabs were cut out of the control board and shaped to the same size. Care was
taken to make sure that the bars from the thermally treated and control material were the
twinned pieces, so originated from the same place in the board. The bars were labelled to
permit identification of the twinned bars. The samples to be studied of 10 mm in length were
cut out from the bars. The samples were dried to oven dry state, measured and weighted and
the density of wood in each sample was determined. All the samples were placed in
desiccators above an oversaturated salt solution ensuring the relative air humidity of
=25 r 2%. The samples were conditioned in such conditions till stabilisation of their mass.
After their weighting and measurements of all dimensions, the samples were moved to
desiccators in which the relative air humidity was =45 r 2% and again after reaching the
equilibrium moisture content they were weighted and measured and moved to subsequent
desiccators of =75 r 2% and =85 r 2% over water table. Measurements were performed on
ten control samples and ten samples modified at 190 C or 200 C.
RESULTS
The ash wood density measured for the modified and unmodified samples are
presented in Table 1. They confirm the earlier reports of Weiland & Guyonnet (2003),
Gündüz et al. (2008), Borrega & Kärenlampi (2008), Gonzalez- Pena & Hale (2009)
indicating that thermal treatment of wood in high temperatures causes decrease in the wood
density, which is the greater the higher the temperature of modification. This decrease is
related to degradation of certain chemical components of wood and evaporation of some of
the products of decomposition and extraneous components of wood.
Table 1. Density of American ash wood in oven dry state before and after thermal treatment
Kind of the material
Control
Modified 190deg
Control
Modified 200deg
min
640
610
575
535
Density [kg/m3]
average
680
650
650
600
max
710
680
690
650
min
Density loss [%]
average
max
3.4
4.4
5.2
6.3
7.1
7.9
Dehydration of hemicelluloses and relative increase in the degree of cellulose
crystallinity as well as the reaction of polycondensation of lignin lead to the reduced
hygroscopicity of wood. It is well seen in Fig. 1 presenting approximate (because of the
method of equilibrium moisture content determination) sorption isotherms of modified and
unmodified wood. Each point in the plot is a mean value calculated for the 10 samples. The
relation between EMC and the relative humidity was approximated by a third degree
polynomial. The degree of reduction in equilibrium moisture content of thermally modified
28
wood (MCmod) in relation to that of the control wood (MCc), shown in Fig. 1, bottom panel,
is calculated as
MCloss
MCc MCmod
u100 [%] .
MCc
Modified
200 deg
190 deg
Fig. 1. The effect of thermal treatment of American ash wood on its equilibrium moisture content at different
relative air humidity values
As follows from the plot of this relation, in the range of molecular sorption (up to M of about
60%), the decrease in the equilibrium moisture content of thermally modified wood is greater
than in the range of capillary sorption. This conclusion seems obvious taking into regard that
thermal modification of wood leads to a decrease in the amount of hydroxyl groups (mainly
as a result of hemicelluloses degradation), so to a decrease in the number of centres to which
water molecules can be attached. This phenomenon causes a reduction on swelling of the
modified wood, and hence, a reduced development of the surface of capillary. This is the
reason for decreased equilibrium moisture content in the range of higher relative air humidity.
The question why the difference between the equilibrium moisture content of the control
29
wood and thermally modified wood decreases in the range of higher relative air humidity will
be possible to answer after exact analysis of development of the inner surface area of wood as
a function of its moisture content.
Changes in the degree of wood swelling as a function of the relative air humidity are
qualitatively similar to those in sorption isotherms. Because of limited volume of the paper,
we present only the results of the maximum degree of wood swelling in transversal directions
(Fig. 2). According to Fig.2, thermal modification of wood at 190 and 200oC caused the
reduction in its swelling by 32% and 55% in the tangential direction and by 32% and 52% in
Fig. 2. Maximum swelling of American ash wood in transversal directions
the radial direction, respectively. The reduced swelling of thermally modified wood is a result
of its decreased hygroscopicity. It can be concluded because the relation between the degree
of the wood swelling as a function of its moisture content, shown for the tangential direction
in Fig. 3, is the same as for unmodified wood.
Fig. 3. The degree of wood swelling in the conditions of air humid versus its equilibrium moisture content
CONCLUSIONS
1. Thermal treatment of American ash wood at 190 or 200qC for 2 hours causes a
decrease in its density by 4.5 and 7%, respectively.
2. The degree of reduction in the equilibrium moisture content of thermally modified
wood is greater in the range of molecular sorption than in the range of capillary
sorption.
30
3. Decrease in the wood hygroscopicity as a result of thermal modification is directly
related to its reduced swelling relative to that of the unmodified wood.
REFERENCES
1. BOONSTRA M.J., ACKER J.V., TJEERDSMA B.F., KEGEL E.V., 2007: Strength
properties of thermally modified softwoods and its relation to polymeric structural wood
constituents. Ann. For. Sci. 64: 679–690.
2. BORREGA M., KÄRENLAMPI P.P., 2008: Mechanical behavior of heat-treated
spruce (Picea abies) wood at constant moisture content and ambient humidity.
European Journal of Wood and Wood Products Vol.66 (1):63-69.
3. GONZALEZ- PENA M.M., HALE M. D.C., 2009: Colour in thermally modified
wood of beech, Norway spruce and Scots pine. Part 2: Property predictions from
colour changes. Holzforschung Vol. 63 (4): 394-401.
4. GÜNDÜZ G., KORKUT S., KORKUT D.S., 2008: The effects of heat treatment on
physical and technological properties and surface roughness of Camiyan Black Pine
(Pinus nigra Arn. subsp. pallasiana var. pallasiana) wood. Bioresource Technology
Vol. 9 (7): 2275-2280.
5. HILL C.A.S., 2006: Wood modification. Chemical, thermal and other processes.
Wiley John and Sons. pp. 260.
6. KOLLLMANN, F., AND FENGEL,D., 1965: Changes in the chemical composition of
wood by heat treatment, Holz Roh und Werkst. 12: 461-468.
7. KOLLMANN, F., SCHNEIDER, A., 1963: On the sorption behavior of heat stabilized
wood, Holz als Roh und Werkst. 21(3): 77-85.
8. THERMOWOOD®HANDBOOK, Finnish Thermowood Association, Helsinki 2003
9. WEILAND, J., AND GUYONNET, R., 2003: Study of chemical modifications and
fungi degradation of thermally modified wood using DRIFT spectroscopy, Holz RohWerkst. 61: 216-220.
10. WINDEISEN E., BÄCHLE H., ZIMMER B., WEGENER G., 2009: Relations
between chemical changes and mechanical properties of thermally treated wood.
Holzforschung Vol. 63 (6): 773-778.
Streszczenie: WáaĞciwoĞci drewna jesionu amerykaĔskiego (Fraxinus americana) modyfikowanego termicznie
w aspekcie jego powinowactwa do wody. W pracy przedstawiono wyniki pomiarów wilgotno ci równowagowej
drewna jesionu modyfikowanego termicznie dla ró nych warto ci wilgotno ci wzgl dnej powietrza oraz stopie
jego sp cznienia w kierunkach porzecznych. Wykazano, e w zakresie sorpcji molekularnej modyfikacja
termiczna drewna powoduje wi ksz redukcj higroskopijno ci ni w obszarze sorpcji kapilarnej. Stwierdzono
tak e, e redukcja stopnia sp cznienia drewna jest nieco wi ksza dla kierunku stycznego ni dla kierunku
promieniowego. Zmniejszone p cznienie drewna modyfikowanego jest ci le zwi zany z umniejszon jego
higroskopijno ci w porównaniu z drewnem niemodyfikowanym.
Department of Wood Science
Pozna University of Life Sciences
60-627 Pozna , Poland
ul. Wojska Polskiego38/42
Selected mechanical properties of thermally modified American ash wood
WALDEMAR MOLI SKI, EWA FABISIAK, UKASZ RODECKI
Department of Wood Science, Poznan University of Life Sciences
Abstract: The compressive strength and bending strength along the grains as well as the elasticity modulus of
American ash wood were determined for thermally modified samples and unmodified samples at the moisture
content of 6%. Thermal modification of wood was shown to lead to a decrease in all mechanical parameters
measured. The reduced values of mechanical parameters of modified wood could be only partly explained by its
decreased density as a result of thermal treatment. As followed from the results, specific strength and specific
elasticity modulus were better indicators of thermal degradation of wood than its absolute mechanical
parameters.
Keywords: ash wood, thermal modification, compressive strength, bending strength, elasticity modulus
INTRODUCTION
As follows from the hitherto published papers on mechanical properties of thermally
modified wood, it can show higher compressive strength, higher bending strength along the
grains, higher linear elasticity modulus and hardness than the unmodified correspondent,
depending on the parameters of treatment and wood species. Other properties such as tensile
strength perpendicular and parallel to grains, shearing strength, dynamic bending strength and
impact strength are always deteriorated (Thermo Wood® Handbook, 2003; Windeisen et al.
2009). Li Shi et al. (2007) studied a few species of Canadian wood and reported that thermal
modification of wood causes a considerable decrease in its static bending strength and a small
decrease in its elasticity modulus. The elasticity modulus of thermally modified birch and ash
wood was even by 15 - 30% higher than that of the unmodified wood. Changes in the Brinell
hardness number were clearly dependent on the type of modified wood. For wood from pine,
spruce and birch trees usually an increase in the hardness was observed, both in longitudinal
and in transversal directions, moreover it was more pronounced on transverse surfaces. On the
other hand, the hardness of thermally modified ash tree was in all directions lower than that of
the unmodified wood. Decrease in all mechanical parameters of wood after thermal treatment
was observed also for nazel wood (Corylus colurna L.) modified at temperatures from the
range 120 - 180qC (Korkut & Hiziroglu 2009). For black pine wood (Pinus nigra Arn.) a
decrease in the compressive strength along the grains was reported, irrespective of the
temperature and time of treatment (Gündüz et al. 2008). Results of these studies are
completely different from the earlier reports by Boonstr et al. (2007) for two species of pine
wood (P. radiata D. and P. sylvestris L.) and for spruce wood (Picea abies Karst.). Borrega &
Kärenlampi (2008), who studied mechanical properties of thermally modified wood as a
function of the decrease in its mass, reported that mechanical strength, strain on failure and
impact strength decreased with decreasing mass of wood. The wood stiffness did not decrease
with decreasing mass up to the decrease of 3%, for greater mass decrease it also decreased
with decreasing mass. The same authors also found out that all mechanical parameters of
wood were the lowest when modification was performed in dry state.
Mechanical parameters of thermally modified wood were usually referred to those of
control unmodified samples, conditioned at the same temperature and relative air humidity. It
means that the mechanical parameters of the modified wood were determined at a lower
moisture content of wood tissue than that of the control samples. This fact was noted by
Arnold (2010) who studied the influence of moisture content of wood on the bending strength
32
of thermally modified beech wood. In view of the above we decided to compare certain
mechanical parameters of thermally modified and unmodified American ash wood at a similar
moisture content of these two samples.
METHODS
The material studied was wood from American ash tree (Fraxinus americana) in the
form of trimmed boards of 25 mm in thickness, in which annual rings were tangent to the
broader surface. Thermal modification was performed in one of the sawmills near Leszno
(Poland) according to the procedure described in ThermoWood®Handbook, Finnish
Thermowood Association, Helsinki 2003. The control samples were sections of about 350
mm in length cut off the above boards. The moisture content of the material subjected to
modification was close to 12%. The modification was performed at 190 or 200qC for two
hours. After the modification and conditioning in open space, from the modified boards a few
slats of the cross section size 25x25 mm were cut out and planned to the cross section size
20x20mm. Analogous slats were cut out from the control material. From the slats of the
modified and unmodified material, the samples for determination of compressive strength and
bending strength along the grains, of the lengths 30 and 300 mm, were prepared. Special care
was taken to make sure that the slats from the thermally treated and control material were the
twinned pieces, so originated from the same place in the board and covered the same annual
rings. The samples with any defects were left out and the good quality samples modified at
either temperature were conditioned in desiccators above the oversaturated NaCl solution.
The mass increase of the samples was monitored till it remained unchanged. The control
samples were kept in the laboratory conditions. After conditioning the modified samples had
the moisture content similar to that of the control samples; that is close to 6%. The
compressive strength and bending strength were measured on a test machine Zwick 50, whose
software permitted calculation of the above parameters and elasticity modulus.
RESULTS
Analysis of the mechanical properties of wood, including thermally modified samples,
needs to be made with reference to its density. Results of measurements of the American ash
wood density, prior to and after modification, performed at the moisture content close to 6%,
are presented in Table 1. These data confirm the earlier reports by Weiland & Guyonnet 2003,
Gündüz et al. 2008; Borrega & Kärenlampi 2008; Gonzalez- Pena & Hale 2009, saying that
thermal treatment of wood causes a decrease in its density, and the decrease is the greater the
higher the temperature of treatment. The thermal treatment of American ash wood for 2 hours
at 190qC led to almost 6% decrease in the wood density, while the treatment at 200qC – to
about 12% decrease in the density of wood relative to that of the initial material.
Table 1. American ash wood density in control samples and thermally modified samples (TM) at 190 or 200qC
measured at the moisture content 6%
Control
672-701-729
691-723-759
Density, U [kg/m3]
Kind of the material
TM 190qC
623-660-719
-
Change density [%]
TM 200qC
620-633-652
-5.85
-12.59
As the compressive strength of wood is closely correlated to its density, the thermally
modified wood shows lower mechanical strength than unmodified one. Thermal treatment at
190oC and 200oC caused a decrease in the compressive strength along the grains by 10 and
20%, respectively, Table 2. As follows from analysis of the specific mechanical strength of
33
the wood, the decrease in the mechanical strength thermally modified wood is not only a
consequence of the decrease in its density. The specific mechanical strength of ash wood
modified at 190qC is by about 5% lower than that of the control sample, while that of the
wood modified at 200qC is by about 10% lower than that of the control one, it can be
concluded that the decrease in wood density is only partly responsible for the decrease in the
wood mechanical strength. The other part of the decrease is assigned to structural changes in
the cell wall. These results prove that the earlier reports e.g. in ThermoWood®, Handbook
(2003) claiming that the thermally modified wood has greater mechanical strength than the
unmodified one are misconceptions following from the fact that the mechanical strength of
the modified and unmodified wood was compared for wood tissues of different moisture
content as the modified and unmodified wood conditioned in the same environmental
conditions (temperature and relative air humidity) reach different equilibrium moisture
contens.
Table 2. Compressive strength of thermally modified and control wood samples measured at the moisture
content close to 6%
Mean moisture Compressive
strength
content
Rc [MPa]
MC [%]
Change in
compressive
strength
Rc [%]
Sample type
Mean density
[kg/m3]
Control
TM 190O C
701
660
5.98
5.71
72-77-80
60-69-76
-10.39
Control
TM 200O C
723
633
5.61
5.25
70-78-85
58-62-65
-20.51
Specific
compressive
strength
Rcs [km]
11.0
10.5
10.7
9.7
Reduction in the mechanical strength of wood as a result of its thermal modification is greater
on bending. For the modification at 190 and 200oC the change in bending strength was 26 and
34% (Table 3), which indicates that the mechanical bending strength is more sensitive to the
structural changes taking place upon thermal modification. The changes in cell wall structure
(first of all depolymerisation of cellulose) have a greater effect on the bending strength than
the changes in wood density. This conclusion follows from the fact that the changes in the
specific mechanical strength are only by 3 and 6% smaller than the changes in absolute values
expressed in MPa.
Table 3. Bending strength of thermally modified and control samples measured at the moisture content MC
Sample
type
Mean
density
[kg/m3]
Control
TM 190O C
708
672
Mean
moisture
content MC
[%]
5.96
5.91
Control
TM 200O C
744
677
6.17
4.56
Bending strength
MOR [MPa]
125-146-164
83-107-129
121-134-140
55-88-125
6%
Change in Mean specific
bending bending strength
strength
MORs [km]
MOR [%]
20.6
-26.71
16.0
-34.33
18.0
13.1
Thermal modification of ahs wood also resulted in a decrease in the elasticity modulus
determined in the static tests upon wood compression and bending. The elasticity modulus of
all wood samples studied is given as mean values in Table 4. Analysis of the changes in
elasticity moduli with those in mechanical strength parameters reveals that the modulus
34
determined upon wood compression changes to a greater degree than the compressive
strength of the wood. Decrease in the elasticity modulus is smaller when it is determined in
the tree-point bending test.
Table 4. Mean values of the elasticity modulus determined upon bending and compression of wood at the
moisture content close to 6%
Elasticity
modulus
determination
Control
Compression
Bending
16281
13358
Elasticity modulus [MPa]
Type of samples
Change
Control
TM 190qC
TM 200qC
in [%]
12500
-23.21
13518
10516
11693
-12.46
11931
11335
Change
in [%]
-22.21
-5.00
CONCLUSIONS
1. Thermally modified ash wood shows a reduced compressive strength and bending
strength along the grains as well as lower elasticity modulus determined in the tests upon
wood compression and bending relative to the corresponding parameters of the
unmodified wood, at comparable moisture content of these two types of wood.
2. The reduction in mechanical parameters of thermally modified wood relative to those of
unmodified one can be only partly explained by decrease in wood density, a considerable
contribution to this process comes also from defects of cell walls.
3. The specific mechanical strength and specific elasticity modulus are more reliable
indicators of thermal degradation of wood than the absolute values as the specific ones
take into regard the changes in wood density.
REFERENCES
1. ARNOLD M., 2010: Effect of moisture on the bending properties of thermally
modified beech and spruce. Journal of Materials Science. Vol. 45 (3):669-680.
2. BOONSTRA M.J., VAN ACKER J., TJEERDSMA B.F., KEGEL E.F., 2007:
Strength properties of thermally modified softwoods and its relation to polymeric
structural wood constituents Ann. For. Sci. 64: 679–690.
3. BORREGA M., KÄRENLAMPI P.P., 2008: Mechanical behavior of heat-treated
spruce (Picea abies) wood at constant moisture content and ambient humidity.
European Journal of Wood and Wood Products Vol.66 (1):63-69.
4. GONZALEZ- PENA M.M., HALE M. D.C., 2009: Colour in thermally modified
wood of beech, Norway spruce and Scots pine. Part 2: Property predictions from
colour changes. Holzforschung Vol. 63 (4): 394-401.
5. GÜNDÜZ G., KORKUT S., KORKUT D.S., 2008: The effects of heat treatment on
physical and technological properties and surface roughness of Camiyan Black Pine
(Pinus nigra Arn. subsp. pallasiana var. pallasiana) wood. Bioresource Technology
Vol. 9 (7): 2275-2280.
6. LI SHI J., KOCAEFE D., ZHANG J., 2007: Mechanical behavior of Qu´ebec wood
species heat-treated using ThermoWood process. Holz Roh Werkst 65: 255–259.
7. THERMOWOOD®HANDBOOK, Finnish Thermowood Association, Helsinki 2003.
8. WINDEISEN E., BÄCHLE H., ZIMMER B., WEGENER G., 2009: Relations
between chemical changes and mechanical properties of thermally treated wood.
Holzforschung Vol. 63 (6): 773-778.
35
Streszczenie: Wybrane mechaniczne wáaĞciwoĞci drewna jesionu amerykaĔskiego
modyfikowanego termicznie. W pracy przedstawiono wyniki oznacze wytrzyma o ci na
ciskanie i zginanie wzd u w ókien oraz modu u spr ysto ci drewna jesionu
ameryka skiego modyfikowanego termicznie i porównano je z analogicznymi wielko ciami
oznaczonymi dla drewna niemodyfikowanego przy wilgotno ci 6%. Wykazano, e
modyfikacja termiczna drewna przyczyni a si do obni enia wszystkich mierzonych
parametrów mechanicznych.
Stwierdzono, e obni one, w porównaniu z drewnem
wyj ciowym, warto ci parametrów mechanicznych drewna modyfikowanego, mo na tylko
cz ciowo t umaczy obni on jego g sto ci . Wykazano, e lepszym wska nikiem
degradacji termicznej drewna od jego bezwzgl dnych parametrów mechanicznych jest
wytrzyma o w a ciwa oraz w a ciwy modu spr ysto ci.
Department of Wood Science
ul. Wojska Polskiego38/42
The influence of long-lasting permanent load with pulling out force on pin
displacement in locally strengthened elements of furniture joints
RAFA MOSTOWSKI
Institute of Combustion Engines and Transport, Pozna University of Technology
Abstract: The influence of long-lasting permanent load with pulling out force on pin displacement in locally
strengthened elements of furniture joints. Current research of elements of modern furniture joints show
appearance in them of intensive rheological phenomena. The paper concentrates on experimental evaluation of
influence of local strengthening with PUR 555.6 nanopreparation of the area of joint in particle board on pin
movement. It was loaded with constant pulling out force – rheological approach. The paper shows methodology
and results of the experiment. The analysis of data with special consideration of modelling aspect of observed
phenomena was conducted.
Keywords: furniture joints, creeping, particle board, local strengthening
INTRODUCTION
Assurance of better construction joints` properties is strictly connected with furniture
quality improvement [2].To achieve it one should eliminate defects of the weakest element of
joints which is particle board. Achievement of such effects without changes in production
technology can be obtained via strengthened particle board in the area of attachment elements
of a joint. It can be done by application of strengthening preparations in wholes performed to
fix other elements of joint. One of such preparations is Kleiberit PUR 555.6 nano. Its
beneficial influence on static properties of joints was confirmed by experiments [6]. However
the problem of local influence of the nanopreparation on rheological phenomena in joints
[5, 7, 8] has not been tested. The aim of this paper is experimental evaluation of the process of
pin movement under load with constant pulling out force in joints elements which had
previously been locally strengthened.
THE SUBJECT AND METHODOLOGY OF THE RESEARCH
The experiment was conducted on Tinius Olsen H5K-T (Fig. 1a) testing machine. To
guarantee set and identical climatically-thermal conditions the testing machine was equipped
in temperature chamber (Fig. 1a). The tested specimens were made from Twinstart (Titus) pin
and locally strengthened particle board (Fig. 1b). Screwing moment was 2,2 Nm and was
obtained by dynamometric screwdriver. The samples were fixed in a holder inside
temperature chamber (Fig. 1a) [5,6,7,8]. The average density of particle board used for
experiment was Uavg = 652 ± 21 kg/m3 and humidity 4 ÷ 6%. The samples were seasoned in
temperature chamber. The temperature of measurements was 25 ± 0.3 °C.
Loading used in individual tests series were respectively 30%, 37% and 46% of static
load [6]. They were obtained by so called ‘straight load way’, and separate options of tests
parameters matched previously made ones [3,7,8]. Only for the biggest load a small
adjustment of one of the parameters was made to reach time of assumed force value in testing
and its relevant characteristics. (Fig. 2) [7, 8].
37
a)
b)
Twinstart (Titus) pin
strengthened area
particle board
(Kronopol)
Fig. 1. (a) Tinius Olsen H5K-T universal testing machine with equipment;
(b) tested specimen (dimensions 100x90x18).
Fig. 2. The characteristics and parameters of creep tests
Short duration creep tests (60h) were conducted because of limited data acquisition
possibilities. Because of limited testing time the research is aimed on the first and partially
second creep stage. They are labelled on characteristics as respectively dashed and solid lines
(Fig.2).
FINDINGS AND ANALYSIS
The curves referring to two first creep stages were obtained during the experiment
(Fig.3a). From the data obtained dependences form load for immediate displacements were
calculated (Fig.3b) and average creep speeds in the second stage (between 54 and 60 test
hours) (Fig. 4).
38
a)
b)
Fig 3. (a) the obtained creep curves; (b) the dependence of immediate displacement from load
Fig 4. Dependence of average creep speed (between 54 and 60 tests hours) from load
39
Also linearity in the sense of Boltzmann [1, 3, 4, 5, 9] was verified via constructing
isochronous creep curves (Fig.5).
Fig 5. Isochronous creep curves obtained during tests of furniture joints elements
CONCLUSIONS
Locally strengthened joints elements show inclination to creep phenomenon however
lower than not strengthened ones. Moreover they show behaviour similar to linear viscoelastic
media (Fig. 5) analogically to earlier tested elements of „traditional” joints [8].
REFERENCES
1. BETTEN J. 2008: Creep Mechanics, Springer – Verlag, Berlin.
2. BRANOWSKI B., POHL P. et all. 2004: Modelowanie pó sztywnych w z ów
konstrukcyjnych, Wyd. AR im. A. Cieszkowskiego w Poznaniu.
3. JAKOWLUK A, 1993: Procesy pe zania i zm czenia w materia ach, WNT,
Warszawa.
4. MORLIER P. 1994: Creep In Timber Structures, Rilem Report 8, Chapman & Hall,
London.
5. MOSTOWSKI R. 2009: Research of creep in elements of furniture joints (pin placed
in the MDF board) in the permanent load state of pulling force, 50. International
Scientific Conference of Departments of Parts and Mechanisms of Machines, SK,
Zilinska univerzita, Vydavatelstvo ZU CD-Rom.
6. MOSTOWSKI R., WIELOCH G. 2009: The influence of local material properties
modification of particleboard in the area of pin screwing in, on basic joint strength
parameters, Proceedings of the 3rd Inernational Scientific Conference „Woodworking
Technique”, University of Zagreb, Czech University of Agriculture Prague, Technical
University in Zvolen, Zalesina, Croatia, pp. 69-74.
7. MOSTOWSKI R. 2009: The use of testing machine Tinius Olsen H5K-Tfor research
rheological proprieties of furniture connections elements, , 50. International Scientific
Conference of Departments of Parts and Mechanisms of Machines, SK, Zilinska
univerzita, Vydavatelstvo ZU CD-Rom.
8. MOSTOWSKI R., 2009: Time-dependent displacement of pin in furniture joint
elements in steady-load conditions of pull-out force, Annals of Warsaw University of
Life Sciences – SGGW, Forestry and Wood Technology No 69, pp.99-103.
9. PENNY R.K., D.L. MARIOTT 1995: Design for creep, Chapman & Hall, London.
40
Streszczenie: Wpáyw dáugotrwaáego obciąĪenia staáą siáą wyrywającą na przemieszczenie
trzpienia w lokalnie wzmocnionych elementach poáączeĔ meblowych. Dotychczasowe badania
elementów nowoczesnych po cze meblowych wykaza y wyst powanie w nich zjawisk
reologicznych o intensywnym charakterze. Praca koncentruje si na eksperymentalnej ocenie
wp ywu lokalnego wzmocnienia nanopreparatem PUR 555.6 okolic z cza w p ycie wiórowej
na przemieszczenie trzpienia obci onego sta si wyrywaj c w uj ciu reologicznym.
Przedstawiono metodyk oraz wyniki eksperymentu. Przeprowadzono analiz wyników ze
szczególnym uwzgl dnieniem aspektu modelowania zaobserwowanego zjawiska.
Pozna University of Technology, Institute of Combustion Engines and Transport, Department of Machine
Designing Methods, ul. Piotrowo 3, 60-965 Pozna , Poland,
E-mail address: [email protected] (Rafa Mostowski PhD. Eng.)
The evaluation of influence of particle boards local strengthening in the
area of pins set in furniture joints – rheological aspect
RAFA MOSTOWSKI
Abstract: The evaluation of influence of particle boards local strengthening in the area of pins set in furniture
joints – rheological aspect. The occurrence of clear rheological phenomena in loaded modern furniture joints
requires the necessity of their minimization [8, 11, 12]. One of the ways is a local modification of material
properties of a particle board via application of PUR 555.6 nanopreparation into the area of pins screwing home.
As far as quality is concerned rheological features of tested elements of furniture joints locally strengthened and
traditional are similar [10, 12].The paper shows a short evaluation of tests conducted on furniture joints of both
kinds. The paper describes the influence of local strengthening on basic parameters of creep process such as:
immediate deformation or creep speed in the second stage.
Keywords: creep, particle board, furniture joints, local strengthening, immediate deformation
INTRODUCTION
In modern furniture constructions during assembly a wide range of different types of joint
is used. They let relatively simple and fast furniture construction without the necessity of
using special tools and technologies. These are undoubted advantages of modern furniture
joints. Unfortunately they are not free from defects. They show low resistance and semi-rigid
characteristics [2]. The causes of such disadvantageous phenomena are most of all materials
of joined elements which are usually particle boards. They have anisotropic properties and
low resistance parameters [6], moreover they show propensity to creep [4, 7]. Rheological
phenomena are also clearly observed in joints which was among others proved in author`s
research [8, 10, 11, 12]. The improvement of disadvantageous properties is possible only by
changing their construction features. It concerns particularly their geometrical and material
features. The paper concentrates on evaluation of influence of change of joints` material
features on their basic rheological parameters. This change is based on modification of
particle board properties by PUR 555.6 nanopreparation in the assembly area of joints
elements [8, 9, 10, 11, 12, 14]. The so far conducted research of this aspect of construction
features changes of joints showed radical advantageous influence on load and stiffness of
joints elements in pin pulling out tests [9, 14].
The main aim of the paper is comparison of basic rheological parameters for furniture
joints elements which have changed and unchanged local areas in particle board under action
of constant pulling force.
THE COMPARISON OF CURVES AND PARAMETERS OF CREEP PROCESS
The creep process and more precisely the process depending on time pin moving under
action of constant pulling out force was tested on universal testing machine type Tinius Olsen
H5K-T. For specimens were used pins for screwing type Twinstart (Titus) with Euro screwthread. PUR 555.6 was applied in pins wholes made in particle board. The loads used were of
327 N, 400N and 495 N. Both experiments and courses obtained on the basis of these
experiments presented below are described in detail in papers [10, 12].
The creep curves described on Fig. 1a-c are concerned with first and partly second phase
of creep [1, 3, 5, 10, 12, 13]. For loading 495 N was used curve having most favourable
course and obtained from tests of not strengthened specimens. Because of technical problems
42
the time of tests was limited to 36 h for traditional samples and 60 h for strengthened samples
[10, 11, 12].
a)
b)
c)
Fig 1.Creep curves for constant load: (a) 327 N; (b) 400 N, (c) 495 N
43
The comparison of immediate deformation and average speed in the second creeping
phase between 32 and 36h of measurement was also conducted (Fig 2).
a)
b)
Fig 2. (a) dependence of immediate moving from load, (b) dependence of average creep speed (between 32 and
36 hour of tests) from load
CONCLUSIONS
The conducted comparison of basic parameters of creep process in tested elements of
joints shows clearly advantageous influence of process of local strengthening. One can
observe shorter time of transient creep (Fig. 1), but it is difficult to be described quantitatively
because of conventionality of beginning of second phase of creep [5]. Moreover immediate
deformations are decreasing but in much smaller degree from average speed in steady creep
state. Insignificant influence on degree of immediate deformation is connected with the
change of stiffness as a result of local strengthening [9].
44
REFERENCES
1. BETTEN J. 2008: Creep Mechanics, Springer – Verlag, Berlin.
2. B. BRANOWSKI, P. POHL et all. 2004: Modelowanie pó sztywnych w z ów
konstrukcyjnych, Wyd. Akademii Rolniczej im. A. Cieszkowskiego w Poznaniu.
3. FINNIE I., HELLER W.R. 1962: Pe zanie materia ów konstrukcyjnych, WNT,
Warszawa.
4. IWASHITA M. 1974: The influence of overlay on creep properties of particleboard,
Bull. Gov. For. Exp. Sta. No 263, pp. 65-72.
5. JAKOWLUK A. 1993: Procesy pe zania i zm czenia w materia ach, WNT,
Warszawa.
6. KOCISZEWSKI M., WILCZY SKI A. 2003: Elastic properties of particleboard as
heterogeneous material, Electronic Journal of Polish Agricultural Universities, Vol. 6,
Issue 2, Wood Technology, Wroc aw.
7. MORLIER P. 1994: Creep In Timber Structures, Rilem Report 8, Chapman & Hall,
London.
Scientific Conference of Departments of Parts and Mechanisms of Machines, SK,
2009 , Zilinska univerzita, Vydavatelstvo ZU, 2009 (Zbornik abstraktov, Zbornik
prispevkov na CD-Rom).
10. MOSTOWSKI R. 2010: The influence of long-lasting permanent load with pulling out
force on pin displacement in locally strengthened elements of furniture joints, Annals
of Warsaw University of Life Sciences – SGGW, Forestry and Wood Technology No
71.
rheological proprieties of furniture connections elements, , 50. International Scientific
12. MOSTOWSKI R. 2009: Time-dependent displacement of pin in furniture joint
Life Sciences – SGGW, Forestry and Wood Technology No 69, pp. 99-103.
13. PENNY R.K., D.L. MARIOTT 1995: Design for creep, Chapman & Hall, London.
14. POHL P., RADZIKOWSKI K., WO PIUK M. 2008: Investigation on the local
reinforcement of chip boards in the place of anchoring screw fasteners, Annals of
Warsaw University of life Sciences – SGGW, Forestry and Wood Technology No 64,
pp. 180-184.
45
Streszczenie: Ocena wpáywu lokalnego wzmocnienia páyt wiórowych w obszarze osadzania
trzpieni poáączeĔ meblowych w aspekcie reologicznym. Wyst powanie wyra nych zjawisk
reologicznych w obci onych nowoczesnych po czeniach meblowych wprowadza
konieczno ich minimalizacji [8, 11, 12]. Jednym ze sposobów jest lokalna modyfikacja
w a ciwo ci materia owych p yty wiórowej poprzez aplikacj nanopreparatu PUR 555.6 w
obszar wkr cania trzpieni. Pod wzgl dem jako ciowym cechy reologiczne badanych
elementów po cze meblowych lokalnie wzmocnionych i tradycyjnych s podobne [10, 12].
W pracy dokonano krótkiego podsumowania bada elementów po cze obu rodzajów.
Przedstawiono wp yw zabiegu lokalnego wzmacniania na podstawowe parametry procesu
pe zania takie jak: odkszta cenie natychmiastowe czy pr dko pe zania w drugim stadium.
Pozna University of Technology, Institute of Combustion Engines and Transport, Department of Machine
Designing Methods, ul. Piotrowo 3, 60-965 Pozna , Poland,
The ranges of local influence of PUR 555.6 preparation and load-carrying
and stiffness of furniture joint elements
R. MOSTOWSKI1, G. WIELOCH2
1)
2)
Department of Woodworking Machinery and Basic Machine Design,
Pozna University of Life Science
Abstract: The ranges of local influence of PUR 555.6 preparation and load-carrying ability and stiffness of
furniture joint elements. The paper shows macroscopic and microscopic evaluation of influence of PUR 555.6
nanopreparation in particle board. The application of the preparation was performed on special specimens
prepared for pin screwing type Twinstart (Titus). Moreover, as an experiment the influence of dosage of
preparation on load-carrying ability and stiffness of furniture joint elements was estimated.
Keywords: particle board, joint furniture, local strengthening, load, stiffness
INTRODUCTION
Upgrading of material features of particle boards directly influence advantageous change
of joints properties and as follows whole furniture construction [1, 4, 10]. The possibility of
influencing particle board properties in the area of joints gives application of PUR 555.6. This
one component preparation on the basis of polyurethane results in local changes of material
structure [12] and upgrading of particle board parameters. The up till now research confirms
advantageous influence of this preparation on static and rheological properties of joints [5, 6,
7, 8, 9, 11]. A very interesting matter from the point of view of practical usage is evaluation
of range of influence and changes of basic load-carrying parameters depending on the
quantity of nanoreparation.
MACRO- AND MICROSCOPIC EVALUATION OF LOCAL MODIFICATION RANGE
During the research were used specimens of particle boards (used in earlier tests of joints
with Twinstart pin by Titus) [5, 6, 7, 8, 9, 11]. The dimensions of wholes were Ø5×12.5 and
were made from front side.
b)
a)
0,5 ml
1 ml
Fig. 1 Local influence of PUR 555.6 preparation: (a) comparison of range of influence depending on preparation
dose (blackish area) (b). microscopic picture of board with penetrating preparation coloured with Sudan black
(×50).
47
b)
a)
1.5 ml
2 ml
Fig. 1 Local influence of PUR 555.6 preparation: (a) comparison of range of influence depending on preparation
dose (blackish area) (b). microscopic picture of board with penetrating preparation coloured with Sudan black
(×50).
In the wholes set in vertical position was dosed by syringe respectively 0.5ml, 1ml, 1.5ml,
2ml of preparation. For preparation colouring Sudan black micro was used which is widely in
biological and chemical tests. Fig. 1 shows a set of Picture of cross sections of samples made
in the axis of whole. The samples were cut on saw disc.
CHANGES OF LOAD-CARRY ALLOWANCE AND STIFFNESS OF JOINTS
ELEMENTS ACCORDING TO PREPARATION DOSE CHANGES
Tests on effect of preparation dose influence, on static parameters of joints were held by
universal testing machine Tinius Olsen H5K-T [5, 6, 7, 8, 9].Earlier experiments with use of
above mentioned machine showed that the loading speed of pin in pulling out test only
imperceptibly influences stiffness and non-linear strengthening [2, 6]. For comparative tests
the support speed was of 1.5 mm/min. The samples had identical geometrical features with
ones used until now. [5, 6, 7, 8, 9]. Moment of pins screw home was for samples with nonstrengthened area and strengthened area (independently from dose) respectively 1 Nm and
2.2 Nm. As a result of tests of pulling out of pins the characteristics of loaded elements were
obtained. Below the obtained characteristics averaged with earlier characteristics of pulling
out performance are shown [6].
The tests were not performer on dose 1.5ml because of insignificant influence in
comparison with other doses. On the basis of obtained characteristics the initial stiffness of
tested samples was determined. The initial stiffness was defined for two characteristics points
representing 10% and 40% of limit load [3, 6]. Te stiffness (cF) and maximum pulling out
forces (Fmax) were compared (Fig 3). Parameters cFS and FmaxS regarded locally strengthened
elements.
48
Fig. 2. Averaged characteristics of pulling out of pins.
a)
b)
Fig. 3. (a) comparison of stiffness of tested samples and maximum pulling out forces of pins. (b) values of forces
pulling out pin and stiffness’s in function of preparation dose.
49
CONCLUSIONS
The performed experiment showed that the sphere of influence of PUR 555.6
nanopreparation is not proportional to applied quantity (Fig. 1). Load-carrying ability and
stiffness in pin pulling out sample have similar reactions. Excessive dose of preparation does
not bring significant changes in basic resistance parameters (Fig. 3). On the basis of
characteristics (Fig. 2) one can presume that to large dose leads to unfavourable effects. The
accuracy of data obtained could be affected by manual dosage of preparation. A very
important matter is also the structure of area operated by preparation, time of cross-linking
and also influence of time and temperature on the degree of crystallization.
REFERENCES:
1. BRANOWSKI B, POHL P. et all.: 2004: Modelowanie pó sztywnych w z ów
konstrukcyjnych, Wyd. Akademii Rolniczej im. A. Cieszkowskiego w Poznaniu.
2. JAKOWLUK A. 1993: Procesy pe zania i zm czenia w materia ach, WNT,
Warszawa.
3. JOŠCÁK P. 1999: Pevnostné navrhovanie nábytku, TU Zvolen.
4. KOCISZEWSKI M., WILCZY SKI A. 2003: Elastic properties of particleboard as
heterogeneous material, Electronic Journal of Polish Agricultural Universities, Vol. 6,
Issue 2, Wood Technology, Wroc aw.
Scientific Conference of Departments of Parts and Mechanisms of Machines, SK ,
Zilinska univerzita, Vydavatelstvo ZU CD-Rom.
7. MOSTOWSKI R. 2010: The influence of long-lasting permanent load with pulling out
force on pin displacement in locally strengthened elements of furniture joints, Annals
71.
rheological proprieties of furniture connections elements, 50. International Scientific
9. MOSTOWSKI R. 2009: Time-dependent displacement of pin in furniture joint
Life Sciences – SGGW, Forestry and Wood Technology No 69, pp. 99-103.
10. NIEMZ P. 1993: Physik des Holzes Und der Holzwerkstoffe, DRW-Verlag.
11. POHL P., RADZIKOWSKI K., WO PIUK M. 2008: Investigation on the local
reinforcement of chip boards in the place of anchoring screw fasteners, Annals of
Warsaw University of life Sciences – SGGW, Forestry and Wood Technology No 64,
pp. 180-184.
12. WIELOCH G., MOSTOWSKI R. 2010: Lokalna modyfikacja w a ciwo ci p yt
drewnopochodnych nanopreparatem PUR 555.6, II KRAJOWA KONFERENCJA
NANO- i MIKROMECHANIKI, Oficyna Wydawnicza Politechniki Rzeszowskiej,
Rzeszów, pp. 85-86.
50
Streszczenie: ZasiĊg lokalnego oddziaáywania nanopreparatem PUR 555.6 a noĞnoĞü i
sztywnoĞü elementów poáączeĔ meblowych. W pracy przeprowadzono makroskopow i
mikroskopow ocen strefy oddzia ywania nanopreparatem PUR 555.6 w p ycie wiórowej.
Aplikacji preparatu dokonano w przyk adowe próbki przygotowane do wkr cania trzpienia
typu Twinstart (Titus). Ponadto eksperymentalnie oszacowano wp yw dawki preparatu na
no no i sztywno elementów po cze meblowych.
Pozna University of Technology,
Institute of Combustion Engines and Transport, Department of Machine Designing Methods,
ul. Piotrowo 3, 60-965 Pozna , Poland,
Agricultural University of Poznan, Department of Woodworking Machine and Basic of
Machine Construction, ul. Wojska Polskiego 28, 60-637 Pozna , Poland,
E-mail address: [email protected] (Grzegorz Wieloch PhD. hab. Eng.)
Forestry and Wood Technology No 72, 2010; 52-56
Contemporary timber-frame construction systems in Poland.
KATARZYNA MYDLARZ
Department of Economic and Wood Industry Management, Poznan University of Life Sciences
Abstract: Contemporary timber-frame construction systems in Poland. The article presents basic information
concerning directions of the wooden building development during the ages. There were presented modern
technological solutions used in wooden building in Poland.
Keywords: Timber framing, modern technologies
INTRODUCTION
Timber is a raw material which has been used by man for hundreds of years. Due to adequate technical
parameters, easy processing and general accessibility it has also been used as construction material. First shelters
built some 70 thousand years ago were built based on timber frame (Pudlis 2005).
Despite sustained technological development and new materials timber is still widely used. It is popular
and appreciated. Although it is one of the oldest raw materials in the world it still inspires. It is used in
traditional constructions and its huge potential facilitates creating ever new solutions also in unconventional
timber building.
HISTORY OF TIMBER FRAMING
The use of timber dates back to Paleolithic times. The range of its use depended
mainly on the type of climatic zone. As the raw material with very good insulation, it has
been used mainly in northern geographic zones as well as places of mild climate (Mielczarek
1999).
Due to its technical parameters timber was used in construction. It has been used to
create whole towns, defense walls, as well as bridges, gates and road surface. First shelters
some 70 thousand years ago were built based on timber frame (Pudlis 2005).
Using timber for house construction was also popular in German carpentry. That
technology was very characteristic for the region. Its beginnings date back to the 7th century
and its popularity stems from the very economical timber management. The feature
characteristic for this type of construction was filling the timber skeleton with cheaper and
more common materials e.g. clay mixed with chaff or fascine, and from the 17th – 18th century
bricks (so called Prussian wall). That type of construction, also called brick nogging wall or
brick and stud work, developed mainly in Germany and England, and the period of its main
glory in Central Europe falls on the 16th and 17th centuries. Still in 18th century special
administrative regulations forced timber usage in East Prussia. From the late Medieval times
few brick nogging constructions from the West commonly known as half-timbering, started to
appear in Poland as well (Trocka-LeszczyĔska 2001).
Timber construction has been forming throughout the centuries. Timber was used to
erect various types of buildings: temples, houses and farms. In Poland, originally, the most
popular and characteristic was log construction. In the second half of the 19th century
buildings in so called vertical-post log construction appeared and during the interwar period
the first notes on using Canadian and American techniques could be found (Czajkowski 1987).
Despite its significance for construction timber was replaced in time by other
materials. It was the consequence of technological development which resulted in recognition
of all novelty appearing on building market as more interesting and useful. In the fifties of the
20th century as the result of forest damage caused by the first and second World Wars the
then state authorities implemented strict regulations, limiting timber usage especially in
52
building industry. Those sanctions as well as contemporary fire regulations to a large extend
weaned both the builders as well as the buyers away from timber resulting in a visible
decrease in its usage (Drewno dla budownictwa 1996).
Only the beginning of the eighties of the former century witnessed again a gradual
promotion of timber and construction methods based on timber. Especially light timber
framing created by an Englishman William Manning was widely propagated. He was the one
who in the thirties of the 19th century described the idea of a timber-framed house. This
technology at the beginning of the 20th century was brought by English settlers to North
America. The thirties due to an intensive economic growth saw its rapid development. As a
consequence size standards for construction elements have been introduced and the distance
between wall posts to which the size of filling materials have been adjusted. An American
construction system called timber-frame have been created (Historia budownictwa
szkieletowego 2003).
Another figure who played a key role in the development of timber-frame
construction was Swedish architect and professor of The Academy of Fine Arts Frederik
Bloom, who approximately 10 years before William Manning described the idea and the rules
of manufacturing timber-frame houses. Joining both concepts (Bloom’s and Manning’s) was
the beginning of a new industry based on prefabrication of timber-frame houses. Manning’s
concept dominated North American countries while Bloom’s system developed mainly in
Scandinavia. Both ideas started intensive work aimed at developing and improving light
timber-frame technology. They facilitated creating its numerous variations, due to which the
technology is still popular and developed across the world (www.budownictwo.info.pl –
2010).
MODERN TECHNOLOGIES IN TIMBER-FRAME CONSTRUCTION
In Poland quite apart from typical ways of constructing timber house innovative
technologies are also implemented. Taking into consideration current trends in houses
construction numerous producers of timber homes use new building ideas. They are most
often the result of the urge to improve technical and heat parameters. Those initiatives are the
response to the ever growing energy costs and the need to come up to buyers expectations
concerning energy efficient buildings. Not only clients needs but also shortage of wood as
well as its ever growing prices are taken into consideration while searching for new
technological solutions. Therefore for the last few years one may observe not only new
technologies emerging on Polish market but also the trend for improving traditional timber
construction systems.
One ex ample of such solutions is Kronopol system, which has been created based on
traditional technology of timber-frame construction. The system launches modern
constructing solutions simultaneously using contemporary wood materials. It has been created
to be used in prefabricated building systems where massive wood has been replaced by so
called I-beam. This beam becomes the major building load-bearing element, which complies
with certain technological requirements at the same time facilitating using the cheaper
material. Kronopol system also uses modern insulation material drown up by the company
called - kronotec MDF. Both construction and insulation material as well as ready-made
product that is prefabricated houses are manufactured within the same company which from
the economic side of production process is very cost efficient not just for the company itself
but as a result also for the clients (www.kronopol.pl. – 06.07.2010 ).
53
Picture. 1 House construction using Kronopol system.
Source: www.kronopol.pl – 06.07.2010
Yet another innovation is launching onto the market so called mobile homes. They are
made using the technology of light timber frame. In such case building frame is put onto
special metal construction set on wheels. Such solution makes possible the transport of the
building and placing it in the site selected by the investor. What is important here from the
point of view of building regulations is that there is no need for obtaining any building
permission, which greatly speeds up and facilitates the moment of putting the building in
place. Since transport of the house significantly limits its dimensions in certain situations
regarding special size requirements it is possible to assemble a few buildings to form one
entity (www.domymobilne.pl – 02.07.2010).
Picture. 2 Examples of mobile houses.
Source: www.abrex.pl – 06.07.2010
Another interesting concept is modular system also called spacious, creating the most
advanced method of buildings’ pre-fabrication. Intensive development of that technology,
mainly in western European countries and the USA, is the result of ever growing trend to
move all possible work out of the building site - Off-Site Construction. In Poland the potential
of this technology is not yet used however the opportunities it creates makes its full
development very likely. In less advanced modular building individual elements form
separate rooms while in the most advanced ones modules embrace half of the building or even
the whole storey (www.apexhomesusa.com - 06.07.2010).
Picture. 3 Examples of modular houses built by Apex company
Source: www.abrex.pl – 06.07.2010
Also interesting and modern solution is HBE technology that uses gluelaminated
timber for building houses. Until recently such wood was used mainly for large-size
constructions. Now it is being used as the construction element of ceilings, roof and walls or
as in case of HBE technology for building whole houses. The companies which use
gluelaminated timber to build houses are most often also the producers of such timber.
54
Therefore their aim is to combine both profiles of their production to form one efficient
system and use the potential given by streamlining their production capacity. An important
factor here is also using the cheaper raw material. All those aspects have a vital impact on
improving production efficiency which results in a lower price of the completed house.
Picture. 4 Building home using HBE technology
Source: www.konsbud.com – 06.07.2010
Aforementioned systems of building timber houses, despite their small share in the
overall number of all construction activities, belong to the most popular innovative solutions
in our country. They are not the only new technologies used in Poland and the opportunity of
getting familiar with them is possible mainly due to the information distributed by the
producers themselves.
CONCLUSION
Conventional timber construction created strong and stable foundation for the
development of modern building technologies. Therefore one may observe contemporary
technologies using solutions from the previous centuries. Skillful combination of forcenturies-reliable timber construction with contemporary building techniques facilitates using
modern finishing materials in carefully selected building design.
However timber construction does not belong to the most popular means of building in
Poland its steady improvement may be the proof of consumers’ demand for innovative
solutions. Despite the fact that the latest trends very often differ from methods used centuries
ago still special unique character of traditional timber construction determines compulsory
directions in the development of modern technologies in timber construction.
REFERENCES:
1. Pudlis E.– Drewno – surowiec wszech czasów – Centrum Informacyjne Lasów
Pa stwowych 2005 r.
2. Mielczarek Z. – Kszta towanie konstrukcji i architektury w budownictwie
drewnianym - Materia y konferencyjne - Drewno i materia y drewnopochodne w
konstrukcjach budowlanych – Wydawnictwo Uczelniane Politechniki
Szczeci skiej 1999r.
3. Czajkowski J. - emkowie. Kultura-sztuka-j zyk. - Materia y z Sympozjum,
Warszawa-Kraków 1987
4. Trocka – Leszczy ska E. - Drewniane budownictwo sakralne – materia y z
sympozjum Kraków 2001
5. Drewno dla budownictwa - Przemys Drzewny 10/96
6. Historia budownictwa szkieletowego - materia y wewn trzne firmy Kronopol
2003 r.
7. www.kronopol.pl – 06.07.2010
8. www.domymobilne.pl – 02.07.2010
9. www.abrex.pl – 06.07.2010
55
10. www.apexhomesusa.com - 06.07.2010
11. www.konsbud.com – 06.07.2010
12. www.budownictwo.info.pl – 28.06.2010
Streszczenie: Wspóáczesne systemy budownictwa drewnianego w Polsce. W pracy
przedstawiono ogólne informacje na temat historii budownictwa drewnianego, które
ewoluuj c na przestrzeni wieków stworzy o stabilne fundamenty dla rozwoju nowoczesnych
technik budowy. Zaprezentowano wspó czesne rozwi zania technologiczne dla budownictwa
drewnianego stosowane w Polsce, zwracaj c jednocze nie uwag na kierunek ich zmian i
nowe trendy.
Katarzyna Mydlarz
Pozna University of Life Sciences,
Department of Economic and Wood Industry Management,
ul. Wojska Polskiego 38/42,
60-627 Pozna ,
Poland
Recycling of insulation boards by reuse
DANUTA NICEWICZ 1), LESZEK DANECKI2)
1)Faculty of Wood Technology, Warsaw University of Life Sciences –SGGW
2)Research and Development Centre for Wood Based Panels Industry in Czarna Woda
Abstract: Recycling of insulation boards by reuse. The study presents possibilities of utilization of used
insulation boards as secondary raw material in the production of these boards. There is presented a simple
method of obtaining pulp from used boards. It was proven that with a growing share of secondary fibers in
boards bending strength decreases, but hydrophobic properties of boards get improved.
Keywords: recovered fiberboards, insulation boards
INTRODUCTION
One of the main directions in the utilization of used products from wood and wood-based
materials is their reuse in the production of particleboards and fiberboards. It is estimated that
over 5 million m3 (2.8 million tons) of such scrap arise in Poland every year. The easiest to
utilize are products which do not contain chemical substances in their structure, i.e. containers
and pallets. Possibilities of utilization of these assortments of recovered wood are presented in
papers of (Nicewicz et al. 2009, Nicewicz, Danecki 2009).
The second important group of wood-based wastes is constituted by used wood-based
panels (particleboards, fiberboards, plywood). The panels should be segregated to different
types. Used particleboards should be utilized in the production of new particleboards while
boards of fibrous structure – in the production of insulation boards, hardboards and MDF.
Used wood-based panels, except wooden components (particles, fibers, veneers) contain
also chemical substances: synthetic adhesives (several to over a dozen percent) and
hydrophobic agents (about 1%). Insulation boards make an exception; they are produced
without adhesives, only with an addition of hydrophobic agents. Additionally, these boards
have a relatively low density (tkg/m3 kg/m3) in comparison with particleboards and
MDF (dtkg/ m3) or hardboards and HDF (tkg/m3). Therefore, for the purposes
of recycling, it is proposed to divide used fiberboards into two groups: the first one –
insulation boards, the second one – hardboards and MDF. Basing on such a division, it can be
assumed that insulation boards will be the easiest to recycle.
There are several possibilities of disintegrating boards to particles (fibers) from which they
are made. Kearley and Goroyias (2004), Kearley (2005) proposed disintegration of used
boards in autoclaves, Roffael et al. (2009), Roffael et al. (2010) suggest the extruder
technique.
Wood fibers can be recovered from insulation boards in a simpler way, by initial
disintegration of boards to pieces of several centimeters in length and soaking of these pieces
in water with mechanical agitation. Such operation can be conducted in tanks with mixers or
in hydropulpers, devices commonly applied in papermaking industry.
57
MATERIALS AND METHODS
Used insulation boards were disintegrated to the form of pulp (furthermore called
secondary pulp) according to the scheme presented in Fig. 1.
scraps of insulation boards
tank
disintegrated scraps
shredder or crusher
hot water
or white water
hydropulper
pulp
Fig.1. Scheme of the process of obtaining secondary pulp
Boards, after initial disintegration, were flooded with warm water and agitated for several
minutes with an electric mixer.
Standard fibers (produced in industrial conditions) and secondary fibers were submitted to a
fractional analysis in a device produced by a company “Defibrator”, with four slotted sieves
arranged in steps, of slot width: 1.0; 0.5; 0.3; 0.15 mm and terminal sieve with 100 meshes
per cm2.
Secondary fibers were added to standard ones in different proportions: 0, 25, 50, 75 and
100%. From the obtained mixtures, there was prepared water slurry of fibers of concentration
1.5 % and insulation boards were produced in laboratory conditions.
Assumed board parameters:
- mass density – 260 kg/m3,
- thickness – 12 mm
The temperature of drying of mats amounted to 1500C, time – 3h.
58
The results of sieve analysis of pulps are summarized below in Table 1.
Table 1. Fractional composition of pulps (%) applied to the production of insulation boards
Sieve slot width (mm)
Pulp from insulation boards (%)
standard
from RW boards
1
1.3
0.7
0.5
9.7
2.6
0.3
8.7
17.4
0.5
1.0
7.6
Sieve 100 meshes/cm2
79.3
71.7
It is apparent from the data presented in the table that the share of fibers retained by
sieves 1-0.15 mm in both pulps was different. However, the quantities of fibers retained by
the sieves 100 meshes/cm2 were similar. This fraction was significant because it constituted
over 70% of all fibers in both pulps. Therefore it was attempted to produce boards from these
pulps. According to the recommendations of the standard PN-EN 622- 4, in insulation boards
there are determined two properties: bending strength and thickness swelling after 2h of
soaking in water.
Figure 2 presents the bending strength of obtained boards.
Fig. 2. Bending strength of insulation boards
1 – insulation boards from standard pulp
2 – boards with 25% addition of RW pulp
4 - boards with 75% addition of RW pulp
5 – boards from RW pulp
As visible in Fig.2, with a growing share of secondary pulp, bending strength of
boards was decreasing. However, bending strength of all boards, including those made from
secondary pulp only, was higher than the value required by the standard (0.8 N/mm2). It
59
seems that the drop of bending strength was caused not only by the morphology of fibers, but
to a high extent by a lower capacity of functional groups to create bonds between fibers. In
the production process, mats from which boards were produced were submitted to drying in
the temperature of 150 – 1600C for 3-3.5 h. This thermal treatment was necessary to give
boards their final properties, but it caused that secondary fibers were weaker than standard
ones.
In Fig.3, there is presented swelling of boards produced with different additions of
secondary pulp.
Fig.3. Swelling of insulation boards after 2 h
1 – insulation boards from standard pulp
4 - boards with 75% addition of RW pulp
5 – boards from RW pulp
As visible, swelling of boards declined with a growing proportion of secondary pulp in
boards.
The reason for the decrease in swelling was probably the same as that for the drop of
bending strength. Secondary fibers had not only lower capacity of bonding with each other,
but also they were absorbing water to a lower degree. However, swelling of all boards was
below the limits set by the standard (10% for boards of thickness 12 mm).
CONCLUSIONS
There is a possibility of recycling of insulation boards by reuse. Used boards can be
disintegrated to the form of wood fibers without a need of defibration. Secondary fibers
obtained from boards cause a lowering of bending strength but improve hydrophobic
properties of boards.
REFERENCES
1. KLIMCZEWSKI M., NICEWICZ D., DANECKI L. 2009: Properties of fiberboard
pulp manufactured from selected types of recovered wood
2. NICEWICZ D, BORUSZEWSKI P, KLIMCZEWSKI M.2009: Usefulness of pulp
from pallet wood in the production of insulation boards. Annals of University of Life
Sciences – SGGW Forestry and Wood Technology No 69, s.122- 126 ;(Ann. WULS
– SGGW, For and Wood Technol. )
60
3. NICEWICZ, D., DANECKI. 2009. : Utilisation of recovered wood in the production
of MDF boards. Annals of University of Life Sciences – SGGW Forestry and Wood
Technology No 69, s. 115- 118(Ann. WULS – SGGW, For and Wood Technol. )
4. NICEWICZ D., DANECKI L. 2009: Drewno z palet i opakowa drewnianych jako
potencjalna baza surowcowa dla przemys u p ytowego
5. KEARLEY V., GOROYJAS G. 2004: Wood panel recycling at a semi-industrial
scale. Proceedings of the 8th European Panel Products Symposium, pp. 1-18
KEARLEY V. 2005: Wood panel recycling using the
Fibresolve process. TRADA Technology Ltd. COST E31/E37, Antibes
.ROFFAEL E., BEHN C., DIX B., BÄR G. 2009: Recycling of UF-bonded
fiberboards. Proceedings of the International Panel Products, Nantes, France 1618.09.2009,
pp.
253-262
.ROFFAEL E., DIX B., BEHN C., BÄR G. 2010: Use of UF-bonded recycling
particle-and fibreboards in MDF-production. European Journal of Wood and Wood
Products 68:121–128
Streszczenie: Recykling technologiczny páyt pilĞniowych porowatych. Praca dotyczy
mo liwo ci wykorzystania zu ytych p yt porowatych jako surowca wtórnego w produkcji
tych p yt. Przedstawiono w niej prosty sposób pozyskiwania mas w óknistych ze zu ytych
p yt. Wykonano p yty porowate przy ró nych udzia ach w ókien wtórnych i standardowych.
Stwierdzono, e w ókna wtórne powoduj obni enie wytrzyma o ci na zginanie statyczne, ale
dodatnio wp ywaj na w a ciwo ci hydrofobowe p yt.
This work is financed by the Polish Department of Education and Science; Project no
N N309136435
Corresponding authors:
Danuta Nicewicz
Faculty of Wood Technology
Warsaw University of Life Sciences – SGGW
02-776 Warsaw, Nowoursynowska str. 159
Poland
Leszek Danecki
Research and Development Centre for WoodBased Panels Industry in Czarna Woda
83-262 Czarna Woda, Mickiewicza str.10a
Poland
e-mail:[email protected]
Influence of freeness of pulp on properties of hardboards
DANUTA NICEWICZ, BEATA PODLE NA
Faculty of Wood Technology, Warsaw University of Life Sciences –SGGW
Abstract: Influence of freeness of pulp on properties of hardboards. Hardboards were produced from pulps of
different freeness (11, 13, 16 and 25DS). Pulps of freeness 11, 13 and 16 DS were obtained as a result of onestage defibration of wood chips, while the pulp of freeness 25 DS. - as a result of two-stage defibration. From
these pulps, there were produced hardboards of thickness 4 mm. It was found that there are possibilities of
producing hardboards of thickness 4 mm without a necessity of refining.
Keywords: freeness of pulp, hardboards,
INTRODUCTION
In Poland, fiberboards are produced by the wet method (hardboards and insulation boards)
and by the dry method (LDF, MDF and HDF). In each of these technologies, wood is
disintegrated to the form of chips and chips – to wood fibers. The fibers differ in morphology
and size depending on the type of produced boards (Klimczewski et al. 2009).
In the wet method, pulp is usually obtained in a 2-stage process, i.e. by defibration of chips
in defibrators and refining of pulp in refiners. In the dry method, chips are defibrated in one
stage in new-generation defibrators. New-generation defibrators are equipped with various
types of refiner plates, which enable production of fibers of required morphology, ensure high
material
efficiency
with
optimum
production
costs
(www.andritz.com,
www.metsopanelboard.com).
In the old-generation defibrators, there are fewer possibilities of technical solutions, but
these devices are submitted to modernization which increases productivity and improves
quality of produced pulp (Dudziec 2004, Dudziec 2008).
There are also changes conducted in particular operations of the technological processes,
both in the wet and dry methods (Borysiuk et al.2006, Groom et al. 2004, Klimczewski et al.
2008, Nicewicz 1999, Nicewicz, Sosi ska 2003). In the production of hardboards, such a
change can consist in one-stage defibration of chips what allows to eliminate the operation of
pulp refining. Of course, in this way there are obtained fibers of different degree of refinement
than in a 2-stage defibration.
In the present study, there was examined the effect of the freeness of pulp on properties of
obtained hardboards. Pulps obtained in one- and two-stage defibration were used in the
researches.
In the production of boards, there were used four pine-wood pulps produced in industrial
conditions. The freeness of pulp amounted to: 25, 16, 13 and 11 DS. The pulp of DS. 25 was
produced in a two-stage process (defibration, refining) while three other pulps were obtained
as an effect of one-stage defibration. Fibers of all pulps were submitted to a fractional analysis
in a device produced by a company „Defibrator” with 4 slotted sieves arranged in steps, of
slot width: 1.0; 0.5; 0.3; 0.15 mm and terminal sieve with 100 meshes per cm2.
The assumed parameters of boards: mass density - 950kg/m3, thickness – 4.0 mm
62
Boards were produced in laboratory conditions. From particular pulps, there were
prepared water slurries of fibers of concentration 1.5%, into which chemical agents were
introduced: PF 51 resin in quantity of 1% relative to completely dry mass of fibers and, in the
same quantity, paraffin in a form of water emulsion. From the slurry, there was moulded a
mat which, after bringing to a humidity of about 60%, was pressed in a plate press according
to a standard pressing curve for hardboards (Oni ko 1972). The temperature of press plates
amounted to 2200 C, time of pressing - 8 minutes.
Properties of obtained boards were tested according to the obligatory standards PN EN 622 -2. Significance of results was examined by means of the Student’s criterion.
Table 1 presents percent share of fractions obtained as a result of sorting of pulps
Table 1. Shares of fractions in pulps of different freeness
Pulp
number/DS
Sieve
1mm (%)
Sieve 0.5 mm Sieve 0.3 mm
(%)
(%)
Sieve 0.15
mm (%)
Sieve Ø 0.1mm
(%)
I/25
0
3
5
14
78
II/16
III/13
1
3
17
27
11
6
11
17
60
47
IV/11
4
22
13
24
37
It results from the data that pulps differed not only in freeness but also in shares of
particular fractions. However, in each of them, the smallest (zero or several percent) was the
share of the fraction retained by the sieve of slot 1 mm, while the greatest (several tens
percent) – by the sieve 0.1 mm. Fraction retained by the sieve 1 mm consists mainly of shives
– insufficiently disintegrated pieces of chips – so it is basically useless and its occurrence in
small quantities testifies to a properly conducted operation of defibration. It can be noticed
that the smaller freeness of pulp the more shives in it. Fibers of fraction 0.5 – 0.3 mm, as
relatively long, significantly affected board strength. Their quantities in particular pulps were
diversified: in the pulp of DS. 25, there were 8% of them altogether, in the pulp of DS. 16 –
28% while in the other pulps – 33 and 35%. It was completely different with the shares of
fibers retained by sieves 0.15 and 0.1 mm. In the pulp of DS. 25, these fibers made 92%
altogether while in the pulp of DS. 11 - only 61%. These relatively short fibers were filling
spaces between big fibers and in this way they facilitated arising bonds between fibers which
brought about a compact structure of boards (Back 1987). Properties of produced boards will
be undoubtedly a resultant of fiber properties.
Properties of obtained boards are presented in Table 2.
63
Table 2. Properties of hardboards produced from pulps of different freeness
Pulp/DS
I/25
II/16
III13
IV/11
Density
Standard
deviation
(kg/m3)
938
935
935
938
(kg/m3)
1.67
1.72
1.85
2.02
MOR
(N/mm2)
44
44
42
28
Standard
deviation
(N/mm2)
6
6
10
6
IB
(N/mm2)
0.26
0.26
0.24
0.17
Standard
deviation
(N/mm2)
0,11
0,06
0,04
0,04
Thickness
swelling
after 24h
(%)
28
30
32
33
Standard
deviation
(%)
4,0
3,5
3,2
4,3
It is visible from the data in the table that densities of all boards were similar and amounted to
about 940 kg/m3, while the properties of boards were diversified. Therefore an influence of
density on board properties should be excluded and differences in properties should be
attributed to the size of fibers. Bending strength of boards was relatively high and for pulps of
DS. 16 and 25 amounted to 44 N/mm2. Much lower was the bending strength of boards made
from pulp of DS. 11, the difference was statistically significant. Probably this low value was
caused by a relatively low content of fibers from fractions 0.15 and 0.1mm. Similar
tendencies were observed in the case of internal bond perpendicular to surface. The lowest
was the value obtained for boards made from pulp of DS. 11 and this value differed
significantly from the internal bond of other boards. It should be noticed that values of
internal bond of all boards were lower than that required by the standard (0.5 N/mm2). It
seems that the obtained values are underrated what often happens in the case of determining
this property in thin boards (several mm of thickness) (Young 2008). However, these data
entitle to comparisons of values of internal bond between variants of boards.
Swelling of boards increased with decreasing freeness of pulp. Boards made from
pulps of freeness 16 and 25 DS. satisfied the requirements of the standard while boards made
from pulp of freeness 13 and 11 DS. exceeded the admissible value by 2 and 3 %
correspondingly.
CONCLUSIONS
To sum up the obtained results, it can be affirmed that there is a possibility of
producing hardboards of thickness 4 mm without a necessity of refining pulp. Boards of this
thickness and density about 950kg/m3 can be produced from pulps of freeness 16 DS.
Lowering of freeness degree to 13 DS. seems possible but probably it will require changes in
the technological process.
The above conclusions should not be applied to boards of other density and thickness.
A continuation of the researches seems necessary.
REFERENCES
1. BACK E.L. 1987: The bonding mechanism in hardboard manufacture. Holzforschung
41:247-258
2. BORYSIUK P., PAWLICKI J., NICEWICZ D. 2006: New types of raw materials in
technologies of wood-based materials .Cost Action E 44- E49 Conference in Valencia
on Wood Resources and Panel Properties, p.277 – 281
3. GROOM LH, SO CL, ELDER T, PESACRETA T, RIALS T. 2004: Effect of refining
pressure and resin
64
4. viscosity and resin flow, distribution, and penetration of MDF fibers. The 7th Pacific
Rim Bio5. Based Composites Symposium, vol 1. p.227–239
6. DUDZIEC M. 2004: Wysokosprawny zespó rozw ókniaj cy do termo rozw ókniarki
o rednicy tarcz miel cych 1000 mm.. Biuletyn Informacyjny OBRPPD w Czarnej
Wodzie nr 1/2 , p.5-11
7. DUDZIEC M. 2008: 307 Nowy, uniwersalny segment miel cy do tarcz o rednicy
1000 mm. Biuletyn Informacyjny OBRPPD w Czarnej Wodzie nr ¾ , p.211-212
8. KLIMCZEWSKI M., NICEWICZ D., MARZEC G.2008: Influence of starch on
properties of insulation boards. Annals of Warsaw University of Life Sciences –
SGGW, Forest and Wood Technology nr 65, s. 202- 205 ). Annals of Warsaw
University of Life Sciences – SGGW, Forest and Wood Technology nr 65, s. 202- 205
9. KLIMCZEWSKI M., NICEWICZ D., DANECKI L. 2009: Properties of fiberboard
pulps manufactured from selected types of recovered wood. Symposium: Proceedings
of the International Panel Products. Nantes, France 16 -18.09.
10. NICEWICZ D. 1999: Utilization of phenol-formaldehyde resin PF51 in fibreboard
11. production. XIV Sympozium: Pokroky vo Vyrobe a Pouziti Lepidel v
Drevopriemysle.
12. Vinne 8-10.09.1999. Wyd. Technicka Univerzita vo Zvolenie, Chemko a.s. Stra ke,
13. s .61-64
14. NICEWICZ D., SOSI SKA K. 2003: Technological changes in the insulation boards
drying
process. Annals of Warsaw Agricultural University. Forestry
and Wood Technology nr 53, s. 261 – 263
15. ONI KO W. 1978: Technologia p yt pil niowych” SGGW AR w Warszawie,
Warszawa
16. YOUNG S. 2008: Quality control besd on internal bond – designing the “Bond-oMatic”. Internal Panel Products Symposium 2008, Espoo, Finland 24-26.10., p.79 86
17. Norma: PN-EN 622-5 P yty pil niowe. Wymagania techniczne. Wymagania dla p yt
formowanych na sucho (MDF)
Streszczenie: Wpáyw stopnia zmielenia masy wáóknistej na wáaĞciwoĞci páyt pilĞniowych
twardych. P yty pil niowe twarde wykonano z mas w óknistych o ró nym stopniu zmielenia
(11,13, 16 i 25DS). Masy o stopniu zmielenia 11, 13 i 16 DS. otrzymano w wyniku 1stopniowego rozw ókniania zr bków, a mas o stopniu rozw óknienia 25 DS. w wyniku 2stopniowego rozw ókniania. Z tych mas wykonano p yty pil niowe twarde o grubo ci 4 mm.
Stwierdzono, e istnieje mo liwo
produkcji p yt twardych o grubo ci 4 mm bez
konieczno ci domielania mas, ale stopie zmielenia masy nie powinien by ni szy od 16DS.
Danuta Nicewicz, Beata Podle na
Faculty of Wood Technology
02-776 Warsaw, Nowoursynowska str. 159
Poland
Thermal conductivity of Norway spruce and European beech in the
anatomical directions1)
PETER NIEMZ*, WALTER SONDEREGGER, STEFAN HERING
Department of Civil, Environmental and Geomatic Engineering, Institute for Building Materials, ETH Zurich,
8093 Zurich, Switzerland
1)
shorted version from a paper submitted to Holzforschung 2010
* Corresponding author:
Abstract: Thermal conductivity of Norway spruce and European beech in the anatomical directions. Thermal
conductivity, thermal diffusivity and heat capacity of Norway spruce (Picea abies [L.] Karst.) and European
beech (Fagus sylvatica L.) were determined for all principal directions (radial, tangential and longitudinal)
depending on the moisture content (MC). Further, between the three principal directions, the thermal
conductivity was determined in 15° steps.
The results show that thermal conductivity increases with increasing MC and shows the highest increase in the
tangential and the lowest in the longitudinal direction. Thermal conductivity is higher for beech than for spruce
in all anatomical directions and the conductivity for both species is more than twice as high in the longitudinal
direction than perpendicular to the grain. The highest thermal conductivity is found for beech at a grain angle of
about 15°. The lowest thermal conductivity shows spruce at an angle of about 60° between the tangential and the
radial direction.
Keywords: thermal conductivity, grain orientation, moisture content, beech, spruce
INTRODUCTION
Accurate knowledge of thermal properties of wood are of high interest in the wood
industry such as drying, thermal treatment, steaming and hot gluing to optimize their process
technology, and are more and more essential in building physics for modelling energyefficient timber constructions. Thereby, thermal conductivity, heat capacity and thermal
diffusivity are the most important parameters necessary to most accurately calculate and
simulate the thermal behaviour of wood. Since wood is an anisotropic material, thermal
conductivity and diffusivity depend strongly on the anatomical direction. Both parameters are
about 3 to 20% higher in the radial than in the tangential direction and in the longitudinal
direction by about 1.5 to 2.75 times higher than perpendicular to the grain. In contrast, the
heat capacity is a material-immanent parameter independent from the anisotropic structure
and has similar values for all wood species. All three parameters are strongly influenced by
temperature and moisture (cf. Kühlmann 1962, Kollmann and Côté 1968, Steinhagen 1977).
The three parameters have the following relationship:
D
O
cU
(1)
where is the thermal diffusivity [m2/s], the thermal conductivity [W/mK], c the heat
capacity [J/kgK] and the density [kg/m3].
The influence of temperature, moisture and density on the thermal conductivity in and
perpendicular to the fibre direction is described in detail by Kollmann and Côté (1968) and is
approximately linear in the density range from 200 to 800 kg/m3, in the MC range from 5 to
35% and in the temperature range from -50° to 100°C.
66
The goal of the presented investigation is a widespread determination of the thermal
conductivity of the two commercially important wood species, Norway spruce (Picea abies
[L.] Karst.) and European beech (Fagus sylvatica L.), in the anatomical directions.
MATERIAL AND METHODS
Material
For the investigations, European beech and Norway spruce samples with dimensions of about
200 mm x 200 mm x 20 mm were tested. The samples were cut from one beech and two
spruce trees from the region of Zurich. The thermal conductivity was measured in the three
principal anatomical directions (radial, tangential, longitudinal) and in 15° steps between
these directions. Therefore, 18 variations per wood species, each of them with 4 specimens,
were tested.
Before testing, the specimens were air-conditioned at 20°C and 65% relative humidity
(20/65). The specimens used for the measurements in the three main directions were
additionally conditioned and tested at 20/35, 20/80, 20/88 and at oven-dry conditions.
Experimental setup
The measurements of the thermal conductivity were carried out with the single-specimen
guarded hot plate apparatus -Meter EP500 (Lambda-Messtechnik GmbH, Dresden)
according to ISO 8302. Figure 1 schematically shows the construction of the apparatus.
Figure 1 Simplified half-diagram of the single-specimen guarded hot plate apparatus. 1, 2, 4 are the inner,
middle and external heating guard rings and 3 the cooling ring (or tempering ring) to protect the test specimen
from environmental influences.
Normally, the samples have dimensions of 500 mm x 500 mm x sample thickness
and the thermal conductivity would be measured circularly with a diameter of 200 mm in the
middle of the sample. The outer parts serve as protection from environmental influences.
Since the investigated samples had only dimensions of about 200 mm x 200 mm, they were
placed centrally on the plate covering the measuring range and insulated from the
environment with wood plates of similar fibre orientation and thicknesses so that the whole
area of 500 mm x 500 mm was covered.
The thermal conductivities were measured at three temperatures: 10°, 20° and 30°C (for
spruce between the radial and tangential direction: at 10°, 25° and 40°C). A difference of 5
and 10 K was used between the heating and the cooling plate, respectively, to measure
67
parallel and perpendicular to the fibre direction. From the values at the three temperatures, the
thermal conductivity at 10°C was determined by a linear regression through the values. The
slope of the regression then corresponds to the temperature coefficient of the thermal
conductivity.
The thermal conductivities of Norway spruce and European beech at 10°C in the
three principal anatomical directions depending on MC are shown in Figure 2. For both wood
species, the thermal conductivities in the longitudinal direction are more than twice as high as
in the directions perpendicular to the grain, and clearly higher in the radial than in the
tangential direction.
Thermal conductivity O[W/mK]
0.4
0.3
S rad
S tang
S long
B rad
B tang
B long
0.2
0.1
0.0
0
5
10
15
Moisture content Z [%]
20
Figure 2 Thermal conductivity ( ) of Norway spruce (S) and European beech (B) in the radial (rad), tangential
(tang) and longitudinal (long) directions depending on moisture content ( ). Linear regressions of Norway
spruce (solid) and of European beech (dashed).
Table 1 Thermal conductivity ( ) depending on MC ( ) at different climates (in brackets, temperature/rel air
humidity) determined on the regression = A + B· , where A = 10.dry ( at dry condition and 10°C) and B =
(change of per percent MC). R2 = coefficient of determination.
Wood
species
Direction
Air-dry
density
[kg/m3]
(20/35)
[%]
(20/65)
[%]
(20/80)
[%]
(20/88)
[%]
Norway
spruce
radial
446
8.9
14.3
16.4
19.2
tangential
410
8.9
14.3
16.9
19.7
longitudinal
425
8.8
14.4
16.8
19.4
radial
640
8.3
14.0
16.2
18.6
tangential
682
8.4
13.9
16.0
18.8
longitudinal
674
8.3
14.1
16.5
18.9
European
beech
68
A (=
B (=
)
10.dry)
[W/mK] [W/mK]
1.08 ·
0.086
10-3
1.28 ·
0.071
10-3
0.44 ·
0.223
10-3
1.93 ·
0.120
10-3
2.35 ·
0.092
10-3
0.31 ·
0.257
10-3
R2
0.97
0.999
0.37
0.95
0.96
0.06
For beech wood, the moisture-dependant gradients of thermal conductivity are nearly
twice as high than for spruce wood in the radial and tangential directions, and are higher in
the tangential than in the radial direction for both species. In contrast, the moisture-dependant
gradient in the longitudinal direction is very low for both species. For elm wood (Ulmus
scabra Mill.), Hr ka and Kurjatko (2006) also found only a small correlation between thermal
conductivity and MC in the longitudinal direction. This results from a high variation of the
values in this direction (cf. the low coefficient of determination (R2) in Table 1). Otherwise,
this can be attributed to the generally higher thermal conductivity of the net cell wall
substance in this direction (0.65 W/mK), which is similar to the thermal conductivity of water
at about 0.60 W/mK (Maku 1954 in Siau 1995). The influence of the MC would be
diminished further if it were taken into account that the thermal conductivity of bound water
is even lower than that of free water (McLean 1941).
Table 2 Parameters of the polynomial function = A + B·x + C·x2 + D·x3 describing the thermal conductivity
between the principal directions of spruce and beech. R2 = coefficient of determination.
Wood species
Norway spruce
European beech
Direction
longitudinal – radial
( grain angle)
longitudinal – tangential
( grain angle)
tangential – radial
( ring angle)
longitudinal – radial
( grain angle)
longitudinal – tangential
( grain angle)
tangential – radial
( ring angle)
A
0.234
B
-5.84 · 10-4
C
-3.58 · 10-5
D
2.88 · 10-7
R2
0.998
0.235
1.87 · 10-4
-5.66 · 10-5
4.10 · 10-7
0.999
0.093
-4
-7.96 · 10
-6
-8
0.75
-6.15 · 10
-5
-7
0.99
-7.51 · 10
-5
-7
0.99
-8
0.95
1.80 · 10
-3
0.251
1.18 · 10
-3
0.250
1.50 · 10
-5
0.127
4.41 · 10
-5
1.15 · 10
7.99 · 10
4.06 · 10
4.78 · 10
-9.59 · 10
Figure 3 Thermal conductivity ( ) at 10°C in and between the principal anatomical directions of Norway spruce
(a) and European beech (b) previously conditioned at 20°C and 65% RH. R = radial, T = tangential, L =
longitudinal, points = measured data, lines = calculated values.
The mean temperature coefficient of the thermal conductivity perpendicular to the
fibre results in 0.22 % per K for spruce and 0.25 % per K for beech and both are in good
agreement with values by Kühlmann (1962), Steinhagen (1977) and Suleiman et al. (1999).
The temperature coefficient parallel to the fibre (0.39 % per K) is clearly higher for both
species than it is perpendicular to the fibre. This is in contrast to the measurements of
Suleiman et al. (1999), who measured lower temperature coefficients parallel to the fibre
69
rather than perpendicular. The differences may be influenced by the different temperature
ranges and measuring methods and should be further investigated.
Figure 3 shows the run of the curves of the thermal conductivity between the three principal
anatomical directions for Norway spruce and European beech. To increase comparability, the
thermal conductivities determined at 10°C after reaching equilibrium MC at standard climatic
conditions of 20°C and 65% relative humidity (RH) were therefore corrected to a uniform
density of 427 kg/m3 for spruce and 673 kg/m3 for beech wood using the following equation:
§O O ·
Ocor Omeas ¨¨ meas air ¸¸U cor U meas (2)
© U meas ¹
where cor is the thermal conductivity corrected to a uniform density, meas the measured
thermal conductivity of the sample, air the thermal conductivity of the air (= 0.026 W/mK),
cor the uniform density and meas the measured density of the sample.
The gradient between two main directions was then determined as a polynomial function of
third degree. The parameters are presented in Table 2. Perpendicular to the grain, the thermal
conductivity of beech increases slightly with increasing ring angle (angle between the
tangential and the radial direction) whereas the thermal conductivity of spruce has the lowest
value on a ring angle of 60°. This may be due to the different anatomical composition of the
two species. Whereas the density within an annual ring of beech only slightly varies, the
densities of early wood and late wood of spruce differ by a factor three so that it can be
compared with a layered material. Thus, without the influence of the rays, the thermal
conductivity in the radial direction would be clearly lower than in the tangential direction
(analogous to series connections compared with parallel connections). This means for a ring
angle of 60°, although the influence of the rays has already decreased, there is still
considerable influence of the earlywood and latewood layers, which reduces the thermal
conductivity. Moreover, as a result of the misalignment of the cells in the tangential direction,
the longest way along the cell walls – at least in the early wood – could be stated for spruce at
a ring angle of about 60°.
From the directions perpendicular to the grain – radial and tangential – to the
longitudinal direction, the highest gradient of thermal conductivity was found between a grain
angle of 15° and 75° for both species. Whereas the highest thermal conductivity for spruce
was measured in the longitudinal direction, for beech it was found at a grain angle of 15°.
This is assumed to be influenced by a high microfibril angle (MFA) in the S2 layers of the
cell walls, which is stated for beech from the literature. For instance, Bucur (1986) measured
a mean MFA of 18° in normal beech wood and Lehringer et al. (2009) even an MFA between
32° and 39.8° for tension and opposite wood. In contrast, Keunecke and Niemz (2008) and
Keunecke et al. (2009) measured a mean MFA of about 10° for spruce wood although it
varies - distributed over the whole stem - over a wide range (cf. Brändström 2001).
CONCLUSIONS
The thermal conductivity was investigated in and between the three principal
anatomical directions of Norway spruce (Picea abies [L.] Karst.) and European beech (Fagus
sylvatica L.). Whereas the highest thermal conductivity was determined to be in the
longitudinal direction for spruce, beech had the highest thermal conductivity at a grain angle
of about 15°. This may be deduced from the different microfibril angles. Also, while the
lowest thermal conductivity was determined for beech in the tangential direction, the lowest
thermal conductivity for spruce was found at a ring angle of about 60°. This may be due to the
different portions of wood rays and the arrangement of the cells. The influence of the MC on
70
the thermal conductivity is higher in the tangential than in the radial direction and very low in
fibre direction.
REFERENCES
1. Brändström, J., 2001: Micro- and ultrastructural aspects of Norway spruce tracheids:
A
2. review. IAWA Journal 22 (4): 333-353
3. Bucur, V. (1986): Mesures sur carottes de sondage de quelques propriétés physiques
de bois de hêtre à fortes contraintes de croissance. Ann. Sci. For. 43 (1): 115-124
4. Hr ka, R.; Kurjatko, S. (2006): Thermal properties of elm wood (Ulmus scabra Mill.).
In: Kurjatko, S.; Kudela, J.; Lagana, R. (editors): Wood structure and properties ’06.
Arbora publishers, Zvolen, Slovakia, pp. 245-249
5. ISO 8302 (1991): Thermal insulation – Determination of steady-state thermal
resistance and related properties – Guarded hot plate apparatus. International
Organization for Standardization, Geneva
6. Keunecke D, Evans R, Niemz P (2009) Microstructural properties of common yew
and Norway spruce determined with SilviScan. IAWA Journal 30 (2): 165-178.
7. Keunecke D, Niemz P (2008) Axial stiffness and selected structural properties of yew
and spruce microtensile specimens. Wood Research 53 (1): 1-14
8. Kollmann F, Côté WA Jr (1968) Principles of Wood Science and Technology.
Volume I: Solid Wood. Springer-Verlag, Berlin/Heidelberg/New York
9. Kühlmann, G. (1962): Untersuchung der thermischen Eigenschaften von Holz und
Spanplatten in Abhängigkeit von Feuchtigkeit und Temperatur im hygroskopischen
Bereich. Holz als Roh- und Werkstoff 20 (7): 259-270
10. Lehringer C, Daniel G, Schmitt U (2009) TEM/FE-SEM studies on tension wood
fibres of Acer spp., Fagus sylvatica L. and Quercus robur L. Wood Sci Technol 43 (78): 691-702
11. MacLean, J. D. (1941): Thermal conductivity of wood. Heating, Piping and Air
Conditioning 13 (6): 380-391
12. Maku, T. (1954): Studies on the heat conduction in wood. Wood Research Bulletin,
No. 13, Wood Research Institute Kyoto University
13. Siau, J. F. (1995): Wood: Influence of moisture on physical properties. Department of
Wood Science and Forest Products, Virginia Polytechnic Institute and State
University, Keene NY, 227 S.
14. Steinhagen, H. P. 1977: Thermal conductive properties of wood, green or dry, from 40° to +100° C: A literature review. Forest Products Laboratory, Forest Service, U.S.
Department of Agriculture, Madison Wisconsin
15. Suleiman, B. M.; Larfeldt, J.; Leckner, B.; Gustavsson, M. (1999): Thermal
conductivity and diffusivity of wood. Wood Science and Technology 33 (6): 465-473
71
Streszczenie: Przewodnictwo cieplne drewna Ğwierka norweskiego i buka europejskiego w
róĪnych kierunkach anatomicznych. Sprawdzono przewodno , dyfuzyjno oraz pojemno
ciepln drewna wierka (Picea abies [L.] Karst.) oraz buka (Fagus sylvatica L.) w g ównych
kierunkach anatomicznych (wzd u nym, stycznym i promieniowym) w zale no ci od
wilgotno ci materia u. Przewodno cieplna pomi dzy g ównymi kierunkami anatomicznymi
zosta a zbadana w odst pach 15° . Badania wykaza y e przewodno cieplna wzrasta wraz
ze wzrostem wilgotno ci i wykazuje najwi kszy wzrost w kierunku stycznym a najmniejszy
we wzd u nym. Przewodno cieplna dla drewna buka jest wy sza ni dla wierka dla
wszystkich kierunków anatomicznych, oraz w ka dym z gatunków ponad dwukrotnie wy sza
w kierunku zgodnym z przebiegiem w ókien ni prostopadle do nich. Najwy sza
przewodno ciepln charakteryzuje si drewno buka pod k tem oko o 15°, za najni sz
wierka pod k tem 60° pomi dzy kierunkami stycznym i promieniowym.
Peter Niemz, Walter Sonderegger, Stefan Hering
Department of Civil, Environmental and Geomatic Engineering,
Institute for Building Materials,
ETH Zurich, 8093 Zurich, Switzerland
Phone: +41 44 632 3230
Fax: +41 44 632 1174
Development of new types of nanocomposite hot-melt adhesives
IGOR NOVÁK1), JÁN SEDLIA IK2), PETER JURKOVI
PAVOL ANTAL2)
3)
, VLADIMÍR POLLÁK1),
1)
Polymer Institute of the Slovak Academy of Sciences, Bratislava, 2)Technical University, Zvolen, 3)VIPO, a.s.,
Partizánske, Slovakia
Abstract: Development of new types of nanocomposite hot-melt adhesives. The paper deals with adhesive and
mechanical properties study of nanocomposites based on ethylene-acrylic acid copolymer during aluminium
bonding. The main objective was to describe the changes of co-polymer properties during increasing of the
nanofiller’s concentration. Based on executed experiments it was found out, that the properties of tested
nanocomposite system were mostly improved depending on the contents of the nanofiller in the system. The
optimum concentration of nanofiller Aerosil 130 SLP in the composite was 2.5 weight % for cohesive
mechanical properties of the system and 3.5 weight % for adhesive ones. Thermal properties of the composite
system showed their maximum within concentration of 4.5 weight % of nanofiller.
Keywords: composite, hot-melt adhesives, nanofillers, EAA co-polymers,
INTRODUCTION
When compared with other types of composites, thermoplastics have some
advantages. They are solvent-free and non-toxic (in most cases); they are characterized by
short time of creation of adhesive bond respectively foil; they are applicable at low
temperatures; they ensure high adhesion to different material and high impact strength of the
joint; they ensure suitable initial strength of adhesive joints; they have good storage stability;
they are proper for gluing automation and increasing labour productivity; no undesirable
moisture is brought into the materials – it means that there is not necessary the long-term
storage of products in conditioned environment.
Nowadays, adhesives based on EAA (ethylene – acrylic acid) copolymers, EVA
(ethylene – vinyl acetate) copolymers, thermoplastic polymers, polyamide, polyesters,
polyethylene, and cellulose (1-6) belong to most often used composites. By addition of a
proper type of filler, mentioned properties can be even improved. The aim of this contribution
is to evaluate the influence of nanofiller on the properties of EAA copolymer.
EXPERIMENTAL PART
As a polymer, EAA copolymer MICHEM Adhesive 20 EAA, with the ratio of 20 %
wt. of acrylic acid and the ratio of 80 % wt. of ethylene, was used. Characteristic properties of
the product are:
– appearance: slight turbidity, almost transparent polymer,
– density: 1.3 g.cm-3,
– melt flow: 1.8 g.10min-1,
– content of volatiles: less than 0.1 wt. %.
Aerosil 130 SLP (Degussa comp.) was used as filler into nanocomposite system.
Aerosil is a flame-patterned silica oxide with an average particle size from 40 to 50 nm.
Picture 1 shows the microscopic image of used filler. As we can see, the structure of the filler
is spherical with a minimal difference in particles size and non-porous/solid surface.
73
Fig. 1 The detail of Aerosil 130 SLP particles
For preparation of nanocomposite system, EAA copolymer was used as the base for
copolymer matrix; which was blended with the filler in concentrations 0, 0.5, 1, 1.5, 2.5, 3.5,
and 4.5 % wt. To mix the mixture, we used Plastograf Brabender PLE 331 heated by silicone
oil in fully filled tank W-50-h (volume 50 cm3). The temperature at mixing of nanocomposite
was adjusted to 180 °C by a thermostat containing tempered silicone medium. Mixing was at
35 rpm-1 for 10 minutes at predetermined temperature. Considering the properties of
individual components, it was preferable to use a triangular blade.
At measurement of adhesive characteristics, the aluminium sheet with thickness of 2
mm and chemical composition listed in table 1 was used.
Table 1 Chemical composition of adherends
Elements
Al
Cu
Fe
Mg
Mn
Ni
Si
Zn
Content (wt. %) 99,5 0,0025 0,32 0,002 0,0035 0,013 0,12 0,007
To measure the peeling strength of adhesive joint, the aluminium foil AlMgSi 0,5 with
thickness of 0.1 mm was used.
Before gluing, the surface of adherents was grinded with 120 grit sandpaper and then
scratches were aligned with 1000 grit sandpaper. Afterwards, the surface was cleaned of
grease and other dirtiness with a mixture of benzin and toluene (volume ratio 1:1). To ensure
a constant spacing between bonded adherents and an equal thickness of adhesive, two distant
wires with diameter I 0.15 mm were placed parallel on the bottom board.
The surface of aluminium foil used in the peeling test was only ungreased with
a mixture of benzin and toluene. To measure cohesive characteristics, it was necessary to
make test blades according to Fig. 2.
77
46
4
4
28
R1
13
1,1
R7
Fig. 2 Specimen for testing of tensile strength
74
To make them, first boards from filled and unfilled systems (dimensions of 74 x 100 x
1.1) were prepared in a shape in hydraulic press at 180 °C, pressure 250 kPa, for 5 minutes.
After cooling of them in a mechanical press, test blades were scissored.
For preparing the samples for testing of adhesive properties (Fig. 3), thin layer of hotmelt adhesive was inserted between two cleaned and ungreased aluminium boards with
distant wires I 0.15 mm. Lap joint was foil-wrapped into teflon foil and the whole sample was
fixed with aluminium foil and put between press plates tempered at 180 °C. At pressure of
100 kPa during 5 minutes, lap joint was formed. The specimens for peeling test were made
similarly.
15
2
60
Dp
dištan ný drôtik
Fig. 3 Lap adhesive joint
Methods of testing included mechanical tests (measurement of cohesive properties and
hardness), adhesive tests (measurement of shear strength of adhesive joint at loading by
tension (2), measurement of strength of adhesive joint at peeling (3), measurement of surface
properties, thermo gravimetric analysis, and measurement of thermal properties.
Measurement of cohesive characteristics included the loading the test blade by tensile
(Fig. 1) at rate of separation of the jaws 50 mm.min-1 with machine Instron 4301 (Instron,
England), when following characteristics were evaluated: maximal tensile strength (MPa),
maximal elongation (%), elongation at rupture (%), tensile strength at rupture (MPa), Young
module of elasticity (MPa), yield strength (MPa), and elongation at yield.
Measurement of hardness in °ShD was done according to ASTM D 2122-2.
Equipment D Scale Durometer PTC 307 – L designed for plastics and react-plastics was used.
To measure adhesive characteristics, the test machine Instron 4301 was used (rate of
separation of the jaws 50 mm.min-1). Following characteristics were evaluated: shear strength
(MPa), relative elongation (%), Young module of elasticity (MPa), and energy of destruction
of adhesive joint (J).
At peel test, the tested specimen was fixed in testing machine Instron 4301. Board A1
was fixed in the low jaw and aluminium foil was fixed in the upper movable jaw. Rate of
separation was slower, only 10 mm.min-1. The values evaluated were: strength of the joint at
maximal loading (MPa), average peel power (N), and average tear tension (N.mm-1). Besides,
also thermo-graphic analysis was done with a thermogravimeter TG-1 (Perkin Elmer, USA).
The Fig. 4 presents the dependence of maximal tensile strength (Rmax) and tensile
strength at breaking (Rr) on the content of filler in composite adhesive. From measured results
follow, that with increasing content of nanoparticles of filler in EAA, the maximal tensile
strength of composite is non-linearly increased. It can be assumed, that further filling will
increase the value of maximal tensile strength, but only for certain concentration. At this
75
27
27
25
25
23
23
21
21
19
19
Rmax
Rr
17
17
15
PevnosĢ v Ģahu pri
roztrhnutí (MPa)
Maximálna pevnosĢ v Ģahu
(MPa)
concentration, EAA composite will be saturated with Aerosil 130 SLP, what causes
insufficient wetting of surface of filler particles and following lowering of max. tensile
strength.
15
0
0,5
1
1,5
2,5
3,5
4,5
Obsah plnidla (hm .%)
Fig. 4. Dependence of max. tensile strength (Rmax), tensile strength at breaking (Rr) on the content of filler
PevnosĢ v šmyku (MPa)
The dependence of adhesive shear strength of joint on the content of filler is on the
Fig. 5. Considering the high specific surface of nanoparticle filler (130 m2.g-1), intense change
of investigated parameter occurs already at low concentrations of filler. Increased dispersion
of measured values can be justified by the possible presence of non-homogeneous in the
composite system, as well as the deteriorative wetting of the aluminium substrate in the
growth of filler content. Substantially is worsened the spreading of copolymer melt adhesive
on the glued surface due to an increase melt viscosity of hot melt glue, which deteriorates the
surface wetting.
16
15
14
13
12
11
10
0
0,5
1
1,5
2
2,5
3
3,5
4
4,5
5
Obsah plnidla (hm.%)
Fig. 5. Dependence of adhesion joint shear strength on the filler content
Character of dependence of average peeling stress is parabolic with the maximum at
the content of filler 3,5 weight % (Fig. 6). Also in this case, measured values show higher
variance, similarly as at measurement of adhesive shear strength of joint.
76
Odlupovacie napätie
(N.mm -1)
1,8
1,5
1,2
0,9
0,6
0,3
0
0
0,5
1
1,5
2
2,5
3
3,5
4
4,5
5
Fig. 6. Dependence of peeling stress on adhesive concentration
Thermo gravimetric analysis confirmed, that temperature of 10 % weight loss
and temperature of sudden weight loss (Fig.7) had after initial decrease increasing tendency.
With the increase of filler particles, the temperature of loss 10% weight is increasing
from 360 °C to 385 °C, which represents a rise up to 8 %. The reason is higher absorption of
heat with Aerosil 130 SLP. Temperatures of sudden loss reach lower values (342 °C up to 374
°C) in comparison with the temperature of loss 10 % weight.
390
Teplota straty 10% hmotnosti
Teplota (°C)
380
Teplota náhleho úbytku hmotnosti
370
360
350
340
330
0
0,5
1
1,5
2
2,5
3
3,5
4
4,5
5
Fig. 7. The dependence of temperature of 10% weight loss and temperature of sudden weight loss on the content
of Aerosil 130 SLP
CONCLUSION
On the base of realised experiments it can be concluded, that nanoparticle filler
Aerosil 130 SLP influences individual properties of filled EAA system differently. The filler
has positive impact to improve the cohesion and adhesion strength, heat resistance, peeling
tension and surface properties of the system. On the other hand, reduces the relative
extension, factors of heat and thermal conductivity and specific volume heat capacity. The
cohesive mechanical parameters of the system can be stated as an optimal concentration of
nanofiller Aerosil 130 SLP 2.5 wt. %, the adhesion properties of 3.5 wt. %. Nanoparticles
composite systems showed the highest heat resistance in filler concentration from 3.5 to 4.5
wt. %. For practical application of filled EAA nanocomposite systems is therefore necessary
to know how to use, environment, application temperature and method of stress and
accordingly select the optimal concentration nanofiller.
77
Acknowledgement
The authors are grateful to the Slovak grant agency VEGA (grants No. 2/7103/27 and
1/0517/09) for the financial support of this research. This paper was processed in the frame of
the APVV projects No. APVV-0773-07 and VMSP-P 0062-09 as the result of author’s
research at significant help of APVV agency, Slovakia.
REFERENCES
1. NOVÁK, I., POLLÁK, V., 2002: Adhezíva využívané na lepenie v automobilovom
priemysle. In: Chemagazín, No.4, ro ník XII, p. 4-5.
2. STN EN 1465: 2000. Stanovenie pevnosti v šmyku preplátovaného lepeného spoja pri
namáhaní v ahu.
3. STN EN 28510-2: 2000. Skúška odlupovania lepeného spoja skúšobného telesa
z ohybného a tuhého adherendu. as 2: Odlupovanie pod uhlom 180°.
4. NOVÁK, I., FLORIÁN, Š., POLLÁK, V., ŽIGO, O., 2010: Tlakovo-citlivé elektricky
vodivé adhezíva. In: Chemagazín, No. 4, ro ník XX, p. 22-23.
5. KINLOCH, A. J., 1994: Adhesion and Adhesives. Chapman and Hall, UK.
6. LU, D., WONG, C. P., 2000: Intern. J. Adhesion and Adhesives, 20, p.189.
Streszczenie: Nowe typy nanokompozytowych klejów topliwych. Praca dotyczy parametrów
klejenia i wytrzyma o ci nanokompozytu bazuj cego na kopolimerze etylenowo-akrylowym
w zastosowaniu do klejenia aluminium. G ównym celem by o okre lenie zmian w asno ci
kopolimeru przy zmiennej zawarto ci nanowype niacza. Wykazano e w asno ci ulega y
poprawie, w zale no ci od zawarto ci nanowype niacza. Optymalna zawarto
nanowype niacza Aerosil 130 SLP wynios a 2.5% wagowego dla w asno ci kohezyjnych oraz
3.5% dla w asno ci klej cych. W asno ci temperaturowe systemu kompozytowego osi ga y
swoje optimum dla 4.5% zawarto ci nanowype niacza.
Ing. Igor Novák, PhD.
Ing. VladimírPollák, PhD.
Ústav polymérov SAV
Dúbravská cesta 9
845 41 Bratislava
Slovakia
[email protected]
Doc. Ing. Ján Sedlia ik, PhD.
Technical University
T.G. Masaryka, 24
960 53 Zvolen
Slovakia
[email protected]
Ing. Peter Jurkovi , PhD.
VIPO, a.s. Partizánske
ul. gen. Svobodu 1069/4
958 01 Partizánske
Slovakia
[email protected]
Properties of pressure-sensitive adhesives using special filler
1)
IGOR NOVÁK, 2)JÁN SEDLIA IK,
DANICA ERVINKOVÁ
1)
ŠT PÁN FLORIÁN,
3)
JÁN MATYAŠOVSKÝ,
4)
1)
Partizánske, 4)VÚSAPL, a.s. Nitra, Slovakia
Abstract: Properties of pressure-sensitive adhesives using special filler. The paper deals with pressuresensitive adhesives and with their electrical properties. The main aim is to verify adhesive and electrical
properties of isotropic electrically conductive PSA composites on the base of poly acrylates filled with silvercoated electrically conductive inorganic particles, i.e. plated basalt particles or wollastonite fibres. Coated
fibrous wollastonite filler is more appropriate for obtaining strong adhesive joints, because it has better strength
parameters of the adhesive joint than PSA containing silver-coated basalt.
Keywords: pressure-sensitive adhesives, filler, electric conductivity,
INTRODUCTION
The pressure-sensitive adhesives (PSA) with electrical properties are widely used in
light-current electro technical engineering [1]. The polymer matrix of this sorts of PSA
contains some dispersed line, as a rule the submicron electrically conductive particles which
are metallic, metal-coated or carbonaceous [2-11]. The electrically conductive PSA
substances are necessary for production of modern electrical and electronic components in the
field of electromagnetic shielding, computer production or cosmic technology. The
preparation of valuable electrically conductive PSA is rather complicated because of
contradictory requirements put forward. The concentration of electrically conductive filler in
PSA must be reasonably low for obtaining appropriate electrical conductivity and PSA must
show suitable cohesive properties.
This contribution is concerned with adhesive and electrical properties of isotropic
electrically conductive PSA composites on the base of poly acrylates filled with silver-coated
electrically conductive inorganic particles, i.e. plated basalt particles or wollastonite fibres.
EXPERIMENTAL PART
The following materials were used for modifying the rheological and adhesive
properties of PSA: statistical (styrene-2-ethylhexyl acrylate) copolymer containing 14 wt. %
of styrene (Eastman, USA), wollastonite fibres (mineral fibres based on calcium silicate)
Nyglos 12 (Nyco, Belgium) with the diameter of fibres = 12 Pm and aspect ratio = 13; basalt
particles (ca 40 Pm) having an irregular spherical shape (Slovakia). The strength of adhesive
joint of PSA composites was found out by testing of adhesive butt joints. The butt joint was
prepared by fixation of two aluminium discs of 40 mm diameter furnished with uniform
deposit of PSA composite and annealed at 100 °C as well as exposed to 0.3 MPa pressure for
20 sec. Both aluminium discs bonded with PSA composites were placed in special holders
equipped with a swinging joint mechanism providing for destruction of adhesive joint in the
direction of tensile load. The mechanism including bonded discs was put into jaws of a 5 kN
universal testing machine Instron 4301 containing a computer software for evaluation of the
results of measurements. The adhesive joints were evaluated by means of tensile tests, the rate
of motion of dynamometer cross head being 10 mm.min-1.
79
The silver-coated inorganic (basalt and wollastonite) fillers were prepared using a
method of electroless plating [3, 4, 8].
Results obtained by measuring electrical and adhesive properties of conductive PSA
composites containing silver-coated inorganic particles or fibres are given in Figs. 1 and 2.
Fig. 1 represents a volume electrical resistivity of the conductive PSA composite on
the base of poly acrylate filled with plated inorganic particles or fibres (silver-coated basalt
particles or wollastonite fibres). The curve a in Fig. 1 gives the concentration dependence of
the volume electrical resistivity of PSA composite for plated basalt particles. It appears that
curve a starts to keep certain stability up to the content of about 50 wt. % of plated basalt
particles in PSA composite. Provided this concentration of plated particles is reached a
percolation conversion sets in PSA composite. This change is evident if the concentration of
65 wt. % of plated basalt particles in composite is attained. While the value of volume
electrical resistivity of non-filled polymer is 12.9 it decreases to 4.1 at 65 wt. % of plated
basalts particles owing to percolation concentration of conductive filler and continues to
decrease to 1.0 at 70 wt.% of this filler in PSA. If we replace the plated basalt particles by
plated wollastonite fibres exhibiting smaller dimensions (the size of irregular spherical
particles of basalt was 40 Pm, whereas the average diameter of wollastonite fibres was about
12 Pm), the percolation concentration can be reached at considerably lower concentration of
plated wollastonite fibres (Fig. 1, curve a), when compared with plated basalt particles (Fig.1,
curve b). Provided the wollastonite is used, the percolation concentration after the 35 wt. %
concentration the significant reduction of the logarithm of volume electrical resistivity from
12.9 to 4.0 takes place. If the content of silver-coated wollastonite in PSA continued to
increase, the value of volume electrical resistivity decreased to 0.2 (for 50 wt. % of the filler
in PSA).
14
a
12
log Rv (Ohm.cm)
10
8
6
4
2
a - AgP
b - AgF
b
0
-10
0
10
20
30
40
50
60
70
80
cAgP (wt.%)
Fig. 1 Volume electrical resistivity of PSA composite vs. content of plated filler: a – silver-coated basalt
particles, b – silver-coated wollastonite fibres
80
Fig. 2 represents the strength of adhesive joint between PSA composite and aluminium
for varying content of conductive filler in the systems PSA/plated basalt, plot a and
PSA/plated wollastonite, plot b. According to Fig. 2, the strength of adhesive joint drops from
the value of 18 x 102 J.m-2 (non-modified PSA) to 110 J.m-2 (70 % filling) for plated basalt
and at 50 % filling shows only about 50% of original strength of adhesive joint and to 65 wt.
% filling with plated basalt particles the joint strength is reduced more than 4-times (3.9 x 102
J.m-2). The situation is different in the case of the plated wollastonite fibres. Because of its
bifilar character, this material establishes electrical contact at the lower filler concentrations in
comparison with plated basalt particles. The plot b in Fig. 2 shows that the increasing
concentration of the plated wollastonite fibres does not produce such considerable change in
strength of adhesive joint as observed in preceding case. The strength of adhesive joint equals
14.7 x 102 J.m-2 for 50 wt. % of wollastonite fibres while the original strength for non-filled
PSA system is 17.6 x 102 J.m-2. But according to results given in Fig. 1, plot b, the electrical
conductivity for 50 wt. % of plated wollastonite fibres is enough. The plated basalt particles
exhibited adhesion to aluminium equal to 8.1 x 102 J.m-2 and electrical resistivity in
logarithmic form of 11.9 while the plated fibres of wollastonite exhibited the strength of
adhesive joint equal to 14.7 x 102 J.m-2 and volume electrical resistivity of 0.2 Ohm.cm. Thus
these PSA displayed high strength of adhesive joint to aluminium and high electrical
conductivity at a given concentration of plated wollastonite fibres when compared with PSA
containing plated basalt particles.
20
-2
Am(J.m )
16
a
12
b
8
4
a - AgF
b - AgP
0
0
10
20
30
40
50
cAgP (wt.%)
60
70
80
Fig. 2 Strength of adhesive joint of PSA composite to aluminium vs. content of the silver-coated filler: a –
silver-coated wollastonite fibres, b – silver-coated basalt particles
CONCLUSION
The electrical properties of PSA on the base of poly acrylate containing plated
inorganic particles are dependent on the type and shape of particles of the used filler. Because
of low parameters of the strength of adhesive joint in PSA containing silver-coated basalt, the
coated fibrous wollastonite is more appropriate for obtaining strong adhesive joints. Like the
preparation of electrically conductive PSA containing carbon particles, the preparation of
81
PSA containing silver-coated inorganic particles requires compromise solution of the problem
with reference to selection of adhesive and electrical parameters of the investigated system.
Acknowledgement
The authors are grateful to the Slovak grant agency VEGA (grants No. 2/7103/27 and
1/0517/09) for the financial support of this research.
This paper was processed in the frame of the APVV projects No. APVV-0773-07 and VMSPP-0044-07 as the result of author’s research at significant help of APVV agency, Slovakia.
This paper was processed in the frame of the Project No. 26220220091 “Re-engineering” of
the Agency of Slovakian Ministry of Education ITMS.
REFERENCES
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2.
3.
4.
5.
NOVÁK, S. FLORIÁN, J., 2003: Mater. Sci. Lett. 22, 1237.
FOULGER,S. H., 1999: J. Appl. Polym. Sci.72, 1573.
NOVÁK, I. KRUPA, I. CHODÁK, I., 2002: Synth. Met. 131, 93.
NOVÁK, I. KRUPA, I. CHODÁK, I., 2004: Synth. Met. 144, 13.
FIGOVSKY,O. L., SKLYARSKY,L. S., SKLYARSKY, O. N., 2000: J. Adhes. Sci.
Technol. 14, 915.
6. SAVOLAINEN,P., KIVILAHTI,J., 1995: J. Adhesion 49, 187.
7. SANCAKTAR,E., DILSIZ,N., 1999: J. Adhesion Sci. 13, 679.
8. NOVÁK, I. KRUPA, I. CHODÁK, I., 2003: Eur. Polym. J. 39, 585.
9. KIM,H. K., SHI,F. G., 2001: Microelectr. J. 32, 315.
10. LU,D., TONG,Q. K., WONG,C. P., 1999: IEEE Transactions on Electronics Packaging
and Manufacturing 22, 223.
11. CHODÁK, I. KRUPA, J., 1999: Mat. Sci. Lett., 18, 1457.
Streszczenie: WáasnoĞci klejów przylepcowych ze specjalnym wypeániaczem. Praca dotyczy
w asno ci klejów przylepcowych i ich w asno ci elektrycznych. G ównym celem by o
okre lenie w asno ci adhezyjnych i elektrycznych izotropowego elektroprzewodz cego
kompozytu PSA na bazie poliakrylanów z wype niaczem z elektroprzewodz cych cz stek
nieorganicznych, takich jak srebrzony bazalt i w ókna wollastonitu. Powlekane w ókna
wollastonitu s lepsze przy otrzymywaniu mocnych po cze , zapewniaj c lepsze parametry
ni PSA z wype niaczem ze srebrzonego bazaltu.
Doc. Ing. Št pán Florián, CSc.
Dúbravská cesta 9
845 41 Bratislava
Slovakia
[email protected]
Ing. Danica ervinková
VÚSAPL, a.s. Nitra
Novozámocká 179
949 05 Nitra
Slovakia
[email protected]
T.G. Masaryka, 24
960 53 Zvolen
Slovakia
[email protected]
Ing. Ján Matyašovský, PhD.
958 01 Partizánske
Slovakia
[email protected]
Investigation of poly(ethylene terephthalate) treated by low-temperature
plasma
1)
IGOR NOVÁK, 1)IVAN CHODÁK, 2)JÁN SEDLIA IK, 1)MARIAN ŠTEVIAR, 1)ANTON
POPELKA, 3)JÁN KOPNÝ
1)
Partizánske, Slovakia
Abstract: Investigation of poly(ethylene terephthalate) treated by low-temperature plasma. Polyethylene
terephthalate (PET) surface was pre-treated by surface barrier discharge (DSBD) plasma at atmospheric pressure
in various processing gases, and/or by radio-frequency discharge (RFD) plasma to improve its surface and
adhesive properties. The changes in chemical structure of the polymer were analyzed by ATR-FTIR
spectroscopy. The surface energy, and its polar contribution as well as peel strengths of adhesive joints to
polyacrylate of PET modified by DSBD and/or RFD plasma significantly increased. The efficiency of
modification depends on the kind of the discharge, used gases, power of plasma source, as well as on time of
modification. The correlation between peel strength of adhesive joint of PET modified by DSBD plasma to
polyacrylate and its surface energy has been found.
Keywords: ATR-FTIR, barrier discharge plasma, radio-frequency plasma, peel strength, polyethylene
terephthalate.
INTRODUCTION
Polyethylene terephthalate (PET) belongs to important polymers, which are frequently
used in many industrial applications, e.g. in automotive industry for cars construction or in
special applications in furniture industry due to its excellent properties. The surface energy of
PET is insufficient in some cases, e.g. bonding, printing, etc. This problem can be solved by
using of various surface modification methods. Several efficient methods have been used to
improve the surface and adhesive properties of polymers [1, 2]. The application of cold
plasmas for pre-treatment of polymeric surface [3-9] belongs to dry, ecological method of
modification, which can tailor polymers in order to modify their surface energy and adhesion
to other materials. The most important feature of the plasma treatment technique is that the
surface properties of polymer can be modified without changing their intrinsic bulk properties
[10-19]. PET with substantially higher surface energy than polyolefin usually does not need to
be pre-treated by plasma for printing, because the level of its surface energy in the untreated
state is higher than the value needed for printing [20, 21].
In this paper the investigation of surface and adhesive properties of PET modified by
DSBD and/or by RFD plasma have been studied using contact angle measurement, peel tests,
ATR-FTIR, SEM.
EXPERIMENTAL
Polymers used
In PET polymer structure (Scheme 1), the aromatic ring and its associated C-C bonds
accommodate rigidity to the macromolecule. The dissociation of chemical bonds in PET
macromolecule on the polymeric surface might occur at C-H or C-C when the polymer chains
receive energy from activated species during modification by low-temperature plasma.
83
Scheme 1. The structure of PET polymer
In our experiments oriented PET foils Tenolan OAN (Technoplast, Czech Republic)
with thickness 0.12 mm and poly (2-ethylhexyl acrylate) (PEHA) (Polysciences, USA) have
been applied. The PET foils were treated in acetone due to elimination of the additives
influencing their surface properties. The adhesive joints of modified PET were prepared by
using a solution of PEHA in ethyl acetate. The layer with thickness 0.12 mm was deposited
on supported biaxially oriented isotactic polypropylene with aid of coating ruler (Dioptra,
Czech Republic).
Modification by plasma
The modification of PET foils by DSBD plasma was performed in laboratory source at
atmospheric pressure in medium of N2 or O2 gases of a technical purity. The DSBD generator
consists of electrodes separated by an alumina dielectric plate. The discharge electrodes
having the area 80 x 80 mm, and consisting of 1 mm wide and 80 mm long tungsten strips,
are fixed on the upper surface of alumina plate. The electrodes are located inside of glass
cover allowing passing of the medium gases. The voltage of DSBD source was 100 V, current
intensity 1A, and frequency was 6 kHz. The power used for modification by DSBD plasma in
N2 or O2 was 100 W.
The RFD source working at reduced pressure 40 Pa in air consists of stainless steel
locked-up vacuum vessel with two circular brass electrodes having a diameter 240 mm. The
voltage of RFD source was 2 kV, current density was 0.6 A, and frequency was 13.56 MHz,
and the power applied for modification of the polymer by RFD plasma in air was 200 W.
Measurements methods
ATR-FTIR
The ATR-FTIR spectroscopy measurements of PET foils were performed with Nicolet
Impact 400 FTIR spectrometer (Nicolet, USA) having a resolution of 4 cm-1, a scan range was
4000 – 400 cm-1, and a total of 1024 scans per analysis. The KRS-5 crystal (thalliumbromide-iodide) has been used for ATR-FTIR measurements.
Surface energy
The surface energy of PET was determined via measurements of contact angles of a
set of testing liquids: re-distilled water, ethylene glycol, formamide, methylene iodide, Dbromo naphthalene) with SEE (Surface Energy Evaluation) system (Masaryk University,
Czech Republic). The drops of testing liquid (V = 3 Pl) were placed with a micropipette
(Biohit, Finland) on the PET foil surface, and a dependence T = f (t) was extrapolated to t = 0.
The surface energy of the polymer as well as its polar and dispersive components were
evaluated by Owens-Wendt-Rable-Kaelble (OWRK) modified by the least squares method
[22]:
84
1cosT J LV
2
J
d
LV
p
J sd 1 / 2 J LV
J sp 1 / 2
(1)
JLV = JLVp + JLV d
Js = Jsp + Jsd
(2)
(3)
Where: T = contact angle (deg),
JLV = surface free energy (SFE) of the testing liquid (mJ.m-2),
d
p
J LV
, J LV
= dispersive component (DC), and polar component (PC) of SFE of the
testing liquid (mJ.m-2),
J sd , J sp = DC and PC of SFE of the polymer (mJ.m-2).
Where, JL is the surface tension, xLp = JLp/JL is the polar ratio of the testing liquid.
Peel strength of adhesive joint
The peel strength of adhesive joint (Ppeel) of PET foil modified by plasma to
polyacrylate was found by peeling of adhesive joint (peel tests) at 90o angle using a 5 kN
universal testing machine Instron 4301 (Instron, England). The adhesive joints were fixed in
aluminium peeling circle. The width of adhesive joints was 20 mm, and its length was 140
mm. The adhesive joints were prepared from modified PET foils and biaxially oriented
isotactic polypropylene impregnated with polyacrylate. The speed of peeling of adhesive joint
was 1.5 mm.min-1.
ATR-FTIR
The chemical changes in surface layer of plasma-treated polymer are analyzed using
ATR-FTIR spectroscopy.
Fig. 1 shows the ATR-FTIR spectra of unmodified PET (Fig. 1 c) as well as the PET
modified by DSBD plasma in N2 (Fig. 1 b) or O2 atmosphere (Fig. 1 a). A surface analysis of
PET modified by DSBD plasma in O2 (10s, Fig. 1 a) and in N2 (10s, Fig. 1 b) can provide an
understanding of the functional chemical groups of the polymer. ATR-FTIR spectra of PET
were measured with the same DSBD plasma treatment times 10s in various processing gases.
For unmodified PET foil (Fig. 1c) , the characteristic IR bands at 1710, 1505 and 1173 cm-1
were observed for CH, C=O, benzene-ring -C-C- stretching vibrations, and ring C-H in plane
bending, respectively. The IR bands at 1358 cm-1 of the wagging, benzene-ring in-plane C-H
bending, and -C-C- stretching vibration bands appeared near 1173 and 1037 cm-1,
respectively. The IR spectrum of DSBD plasma treated PET in Fig. 1b (N2 plasma) and Fig.
1a (O2 plasma) contains some important changes in comparison with IR spectrum of
unmodified PET. For DSBD modified PET the broadening of the C=O stretch at 1710 cm-1
have been appeared due to oxygen-containing sites creation. The content of C=O groups is
higher for PET modified by O2 DSBD plasma (Fig. 1a) comparing to N2 plasma (Fig. 1b) and
consequently the broadening peak at 1710 cm-1 for O2 plasma modified PET was found.
85
Fig. 1 ATR-FTIR spectra of unmodified PET (1 c), PET modified by DSBD plasma in
N2 (1 b), and in O2 atmosphere (1 a)
Surface energy and peel strength of adhesive joint
The surface energy of PET foils modified by DSBD in O2 and N2 plasma at
atmospheric pressure and by RFD plasma in air at reduced pressure vs. activation time is
shown in Fig. 2.
85
A
80
a
75
80
B
70
b
65
70
SFE (mJ.m-2)
SFE (mJ.m-2)
75
65
60
60
55
50
45
55
40
DSBD
50
45
0
5
10
15
Activation Time (s)
RFD
35
30
20
0
20
40
60
80
Activation Time (s)
100
120
Fig. 2 Surface energy of PET foil modified by DSBD plasma (A): in O2 (a) and in
N2 (b) or RFD plasma (B) in air vs. activation time
The surface energy of PET during modification by DSBD plasma in O2 and N2
significantly increased in comparison with untreated polymer. According to Fig. 2, plot a the
surface energy of PET modified by DSBD plasma in O2 increases from the initial value 47.8
86
-2
SFE, PC of SFE, DC of SFE (mJ.m )
mJ.m-2 for untreated PET up to 82.6 J.m-2 for 20 s of modification by plasma. Fig. 11A, plot b
shows the surface energy of PET modified by DSBD plasma in N2. The values of PET surface
energy treated in N2 by DSBD plasma were lower in comparison with surface energy of PET
modified by the same method in O2. The PET modified by RFD plasma in air (Fig. 11B)
reached the same level of pre-treatment for substantially longer time of activation by plasma.
The surface energy of PET treated by RFD plasma at reduced pressure in air reached after 60
s of modification 74.2 mJ.m-2. Comparing Fig. 2 A, plot a and Fig. 2 B we can conclude, than
the same value of the PET surface energy modified by RFD plasma was achieved for 6 times
longer time of modification in comparison with DSBD plasma treatment.
The results of measurements of surface energy of PET modified by RFD plasma, its
polar component (PC) and dispersive component (DC) of the surface energy vs. activation
time are summarized in Fig. 3. The total surface energy of PET treated by RFD plasma
increases with time of activation from 47.8 mJ.m-2 (unmodified polymer) up to 72.4 mJ.m-2
(modification by RFD plasma, 120 s).
80
75
70
65
60
55
50
45
40
35
30
25
20
15
10
5
0
a
b
c
0
20
40
60
80
Activation Time (s)
100
120
Fig. 3 Surface energy (a), its polar (b) and dispersive (c) component of PET modified
by RFD plasma in air vs. activation time
The polar component of the surface energy increased after modification by RFD
plasma in argon from 6.8 mJ.m-2 (unmodified sample) to 31 mJ.m-2 after 120 s of RFD plasma
treatment. However, the dispersive component of surface energy of PET modified by RFD
plasma with activation time does not change significantly (from 41.0 mJ.m-2, unmodified PET
to 41.4 mJ.m-2, RFD, 120 s). Both used processing gases, i.e. oxygen as well as nitrogen reach
the same relation between peel strength of adhesive joint and surface energy of PET:
Ppeel = 309.5 – 1719.8. exp(- SFE/23.9).
CONCLUSIONS
(i)
DSBD plasma modified PET shows by ATR-FTIR measurement the broadening of the
C=O stretch at 1710 cm-1 due to oxygen-containing sites creation,
(ii) surface energy of PET modified by DSBD and RFD plasma significantly increases, this
increase was higher for oxygen in comparison with nitrogen,
(iii) peel strength of PET to polyacrylate modified by DSBD plasma or RFD plasma
significantly increased,
87
(iv) correlation between peel strength of adhesive joint of PET modified by DSBD plasma
in oxygen or nitrogen to polyacrylate have been found:
Ppeel = 309.5 – 1719.8. exp(- SFE/23.9).
Acknowledgements
The authors are grateful to Slovak Grant Agency VEGA (grants No. 2/7103/27 and
1/0517/09) for the financial support of this research.
This paper was processed in the frame of the Project of Slovakian Ministry of Education
“Stimuly“ Req-00151-0001 as the result of author’s research.
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1. CIOFFI, M.O.H., VOORWALD,H.J.C., MOTA R.P., 2003: Mater. Character. 50, 209.
2. POLETTI, G., ORSINI, F., RAFFAELE-ADDAMO, A., RICCAREDI, C., SELLI, E.,
2003: Appl. Surf. Sci. 219, 311.
3. SHENTON, M.J., LOWELL-HOARE, M.C., STENENS, G.C., 2001: J. Phys. D, Appl.
Phys. 34, 2754.
4. ERNÁKOVÁ, L., KOVÁ IK, D., ZÁHORANOVÁ, A., ERNÁK, M., MAZÚR, M.:
Plasma Chem. Plasma Process. 25 (2005) 427.
5. ODRÁŠKOVÁ, M., RÁHE , J., ZÁHORANOVÁ, A., TI O, R., ERNÁK, M., 2008:
Plasma Chem. Plasma Process. 28, 203.
6. NOVÁK, I., POLLÁK, V., CHODÁK I., 2006: Plasma Process. Polym. 3, 355.
7. OHARE, L.A. SMITH, J.A., LEADLEY, S.R., PARBHOO, B., GOODWIN, A.J.,
WATTS, J.F., 2002: Surface Interface Anal. 33, 617.
8. DESHMUKH, R.J., BHAT, N.V., 2003: Mater. Res. Innov. 7, 283.
9. RICCARDI, C., BARNI, R., SELLI, E., MAZZONE, G., MASSAFRA, M.R.,
MARCANDALLI, B., POLETTI, G., 2003: Appl. Surf. Sci. 211, 386.
10. BARNI, R., RICCARDI, C., SELLI, E., MASSAFRA, M.R., MARCANDALLI, B.,
ORSINI, F., POLETTI, G., MEDA, L., 2005: Plasma Process. Polym. 2, 64.
11. ADEMOVIC, Z., WEI, J., JENSEN, B.W., HOU, X., KINGSHOTT, P., 2005: Plasma
Process. Polym. 2, 53.
12. NOESKE, M., DEGENHARDT, J., STRUDTHOFF, S., LOMMATZSCH, U., 2004:
Intern. J. Adhes. Adhesives 24, 171.
13. RÁHE , J., ERNÁK, M., HUDEC, I., ŠTEFE KA, M., KANDO, M., CHODÁK, I.,
2000: Plasmas Polymers. 5, 119.
14. NOVÁK, I., CHODÁK, I., 1998: Angew. Makromol. Chem. 260, 47.
15. ŠIMOR, M., RÁHEL, J., ERNÁK, M., IMAHORI, Y., ŠTEFE KA, M., KANDO, M.,
2003: Surf. Coat. Technol. 172, 1
16. JAN A, J., S AHEL, P., KR MA, F., LAP ÍK, L., 2000: Czechoslov. J. Phys. 50, 449.
17. TSUCHYIA, Y., AKUTU, K., IWATA, A., 1998: Progress in Org. Coat. 34, 100.
18. LIU, C., CUI, N., BROWN, N.M.D., MEENAN, B.J., 2004: Surf. Coat. Technol. 185,
311.
19. BHAT, N. V., UPADHYAY, D. J., 2003: Plasma Chem. Plasma Proces. 23, 389.
20. MANENQ, F., CARLOTTI, S., MAS, A., 1999: Angew. Makromol. Chem. 271, 11.
21. CHENG, T. S. LIN, H. T., CHUANG, M. J., 2004: Mater. Lett. 58, 650.
22. TOUFIK, M., MAS, A., SHKINEV, V., NECHEV, A., ELHARFI, A., SCHUE, F., 2002:
Eur. Polym. J. 38, 203.
88
Streszczenie: Politeraftalan etylenu traktowany plazmą niskotemperaturową. Na PET
oddzia ywano powierzchniowym wy adowaniem plazmy (DSBD) oraz plazm o cz sto ci
radiowej (RFD) w ró nych gazach, w celu poprawy w asno ci powierzchniowych i
adhezyjnych. Badano zmian struktur chemicznych polimeru za pomoc spektroskopu ATRFTIR . Energia powierzchniowa, jej rozk ad oraz przylepno PET modyfikowanego plazm
DSBD oraz RFD znacz co wzros a. Efektywno modyfikacji zale y od typu wy adowania,
typu gazu oraz czasu trwania procesu. Wykazano korelacj pomi dzy przylepno ci po cze
PET modyfikowanych plazm DSBD a energi powierzchniow .
Ing. Ivan Chodák, CSc.
Dúbravská cesta 9
845 41 Bratislava
Slovakia
[email protected]
T.G. Masaryka, 24
960 53 Zvolen
Slovakia
[email protected]
Ing. Ján Kopný, PhD.
958 01 Partizánske
Slovakia
[email protected]
Annals of Warsaw University of Life Sciences - SGGW
Analysis of geometrical deformations of furniture fronts
SYLWIA OLE SKA1), MICHA ROSZKOWSKI2), ANDRZEJ CICHY2), PIOTR BEER2)
1)
2)
Staldrew M. Czwarnok, G. Wo niak-G a ewska Sp.j., Ostrów-Kania, Poland
Department of Construction and Technology of Final Wood Products, Warsaw University of Life Science,
Warsaw, Poland
Abstract: Analysis of geometrical deformations of furniture fronts. The aim of the study was to verify
deformations of asymmetrically veneered panels using industrial glues. To realise the aim designing and building
of special stand for analysis of deflections of furniture fronts was done. After veneering boards became convex
as it was expected, but the level of deformations for different glues was not equal. It is possible to avoid
deformation of asymmetrically veneered panels.
Keywords: asymmetrically veneering, deformations, panels, glue
INTRODUCTION
Nowadays furnitures are produced often with using wood- based panels. During last
years it has been believed that the only good method of veneering wood based panels is
covering it by the same material on both sides. It was like that because asymmetrical
veneering causes geometrical deformations [Prz dka i Szczuka, 1974]. Analysis of panels
deformation is especially important when composite materials are taken into the consideration
[Negri at all, 2009].
Anyway, today it is known that symmetrical veneering is more expensive than the option
where unseen side of furniture is covered by a material which has less decorative and
mechanical properties, but is cheaper. The cost of symmetrical veneering is the most
important reason to find other solutions for veneering [Ostrowski i Roszkowski, 2009].
Unfortunately, now the asymmetrical veneering is done intuitively. It is obvious that it
would be better, if this method was supported on some results of studies. Asymmetrically
veneered panels are composites in which a glue, that connects materials of different
properties, is a key to find the solution.
The aim of the study was to verify deformations of asymmetrically veneered panels using
industrial glues. To realise the aim designing and building of special stand for analysis of
deflections of furniture fronts was done.
The measurement stand composes of elements as shown in figure 1, but the photo of the
measurement stand is shown in figure 2.
90
11
5
4
3
2
8
9
1
7
6
10
Fig. 1. The scheme of the measurement’s station (1- reference plane, 2- measurement strip, 3- measurement area,
4- top constant peg, 5- left bottom peg, 6- right bottom peg, 7- top adjustable peg, 8- left block that hold sample
during measurement, 9- left block that hold measurement strip and sample during measurement, 10- block,
which the sample is levelled with, 11- top block that hold the measurement strip)
Fig. 2- The photo of the measurement stand
Designed place is destined for samples of dimensions 900x450mm and 18mm of
thickness. The reference plane of this place is perfectly levelled. It has dimensions
650x1250mm and is made of plywood.
To defined plane there are fixed four pegs. Three of them have constant height (30mm).
One of them is adjustable so it avoid deflections of sample. All pegs are fixed in the same
distance from the edge of the base (235mm from the shorter edge and 130mm from the longer
91
one). During measurements of panels is situated so her edges are distant the same from each
peg.
In the distance of 100mm from the longer edge of the base and 125mm from the shorter
one there are fixed higher brackets. They are base for the aluminium strip. It goes from one
corner to the other one that is placed diagonally. The strip can be replaced because it is useful
to change its position. The strip is additionally stabilized by the blocks that are placed
unchangeable on the one side of the strip. To described strip it is possible to fix correctly the
depth gauge. Its precision is 0,01mm.
There were assigned five areas on the surface of the measurement strip. In each area five
measurements were made. In studies, the comparative quantities are arithmetic means of the
measurements from each area.
There were studied samples that were asymmetrical veneered with using two kinds of
rigid glues. To verify results always two samples were veneered with using the same type of
glue. All samples were veneered in the same conditions: temperature t=22°C and pressure
P=1,5MPa. After veneering boards were stored during 5 days. In studies, boards were
veneered in described ways:
1. First group of samples was cold- pressed with using MULTIBOND 2015, which is
crosslinking polyvinyl acetate emulsion adhesive. The most important properties of
MULTIBON2015 are density r=1,11g/cm3 and viscosity 3,5Pas. The press time
amounted 35 minutes and the used spread amounted 140g/m2 .
2. Second group of samples was cold- pressed with using BISON TR550, which is
contact glue based on caoutchouc. The most important properties of BISON TR550
are density r=0,80g/cm3 and viscosity 0,2Pas. The press time amounted 0,05 minutes
and the used spread amounted 150g/m2.
To make studies more useful, all boards were measured in four states, as follows:
unveneered board, one-side veneered board, unvarnished, one- side veneered board, varnished
once, one-side veneered board, varnished twice.
RESULTS AND DISCUSION
The results of the studies are shown in figures 3 and 4. The graphs show shape of the
boards in diagonal direction. Both unveneered samples were concave on measured side. After
veneering boards became convex as it was expected. The interesting result is that
deformations do not have the same values. The maximum deflexion of board veneered using
crosslinking polyvinyl acetate emulsion adhesive glue is 3,48 mm. The maximum deflection
of contact glue based on caoutchouc is 1,89 mm. It means that study of mechanical properties
of glues can lead to find a glue that will diminish asymmetrically veneered boards. In this way
glue in the composite, consisted of panel and two covering it coatings of different mechanical
properties, will enable that elements change dimensions in separate manner. Stresses coming
from one coating will not deform board.
92
Board no 1
4
3,5
Unveneered board
Deflection [mm]
3
2,5
One-side veneered board,
unvarnished
2
varnished once
1,5
1
varnished twice
0,5
Perfect board
0
-0,5 1
2
3
4
5
-1
The measurement area
Fig. 3- The graph that shows deflection of the board that was asymmetrically veneered with using
MULTIBOND2015
Board no 2
4
3,5
Unveneered board
Deflection [mm]
3
2,5
unva rnished
2
varnished once
1,5
1
varnished twice
0,5
Perfect board
0
-0,5 1
2
3
4
5
-1
The measurement area
Fig. 4- The graph that shows deflection of the board that was asymmetrically veneered with using BISON
TR550
CONCLUSIONS
Conducted research shows that there is a general tendency that samples
asymmetrically veneered with using rigid glues are characterized by deflection. However, the
most important influence on the level of geometrical deformations of the board has properties
of glue. It is possible to avoid deformation of asymmetrically veneered panels.
REFERENCES
1. PRZ DKA W., SZCZUKA J., 1974: Technology of furnitures, part II, WSiP (in polish)
2. NEGRI M., SANDAK J., KOWALUK G., PA UBICKI B., 2009: Form and mass
changes of composite panels under variable environment humidity, Drewno-Wood
no182: 7-16
93
3. OSTROWSKI A., ROSZKOWSKI M., 2009: Draft analysis of one-side veneered
element’s deformations, Wood Research Slovakia (in print)
Streszczenie: Analiza deformacji geometrycznej frontów meblowych. Celem pracy by a
analiza deformacji p yt okleinowanych asymetrycznie przy u yciu klejów przemys owych.
Aby to osi gn zaprojektowano i zbudowano specjalne stanowisko do analizy zniekszta ce
frontów meblowych. Po okleinowaniu p yty sta y si wypuk e, zgodnie z przypuszczeniami,
ale stopie deformacji by zmienny dla ró nych rodzajów klejów. Jest wi c mo liwe
unikni cie zniekszta ce asymetrycznie okleinowanych p yt.
Sylwia Ole ska,
Staldrew M.Czwarnok, G.Wo niak-G a ewska Sp.j.,
Ostrów-Kania 21A,
05-311 D be Wielkie, Poland
Micha Roszkowski, Andrzej Cichy, Piotr Beer,
Department of Construction and Technology of Final Wood Products,
Warsaw University of Life Science,
Nowoursynowska 159,
02-776 Warsaw, Poland
Selected mechanical properties of steam kiln–dried wood determined on the
basis of cutting power
K. A. ORLOWSKI1, M. A. WIERZBOWSKI2
1
University of Technology, Poland
2
Heat Technology Department, Mechanical Engineering Faculty, Gdansk University of Technology, Poland
Affiliation of Coauthor, Address, Country
Abstract: Selected mechanical properties of steam kiln–dried wood determined on the basis of cutting power. In
this paper results of fracture toughness (specific work of fracture) and shear yield strength of steam kiln–dried
wood determined simultaneously on the basis of cutting power measurement are presented. Wood species,
namely oak (Quercus robur L.) and pine (Pinus sylvestris L.) from the northern part of Pomerania region in
Poland, were subject of steam kiln–drying process in a laboratory kiln, specially designed and manufactured for
the Gdansk University of Technology. It has been recognized that steam wood drying causes a decrease of the
mechanical properties of the wood such as: fracture toughness and shear yield strength. Those mechanical
properties were determined on the basis of the modern fracture mechanics.
Keywords: steam kiln-drying, wood, fracture toughness, shear yield strength, cutting power
INTRODUCTION
In the lumber manufacturing process, drying is one of the most costly consuming
operation in terms of energy and time. Reduction of the energy consumption and drying
processing time are currently two important objectives of timber industry. Drying in
superheated steam is economically justified because of the shorter processing time and
reduced energy consumption in comparison to drying in hot air. Evaporation of free water
does not change wood shape and main dimensions during process of wood drying. With the
loss of water evaporation zone moves deeper into the wood. The proper conduct of the drying
process allows faster extraction of water [1 Gard, 2 Wierzbowski et al.]. The drying process
was conducted in the experimental kiln (0.55 m3 load capacity), equipped with a control
system, especially designed at the GUT. There are two chimneys at the top to control pressure
and environment conditions inside the kiln. The test stand is also equipped with a heat
exchanger, which is supplied by exhausting gases from a furnace, allowing spread water to
evaporate on its surface. Generated steam, by the circulation fan, is distributed between dried
wood piles. The kiln is powered by the heat from both a heat exchanger, supplied with
exhaust gases from burner, and fan’s engine. That kind of location allowed us to minimize
energy losses outside the kiln.
The drying time in the kiln is significantly reduced, nevertheless, the wood colour is
changed. Thus, this phenomenon can testify that also mechanical properties could be also
varied. For that reason, the mechanical properties of wood samples before and after an
accelerated drying process have to be estimated. Since, Patel et al. [3] claim that cutting tests
could be used as a substitute for fracture tests, moreover, cutting forces may be employed to
determine not only toughness but also shear yield strength for a range of solids, including
metals, polymers, and wood [4 Atkins], it was decided to apply the methodology proposed by
Orlowski & Atkins [5], and also described by Orlowski & Palubicki [6].
Samples were dried in the experimental kiln, in which the drying process consists of three
phases. In the first phase wood material temperature was increased up to 95°C with scheduled
95
progress, and water is supplied to the kiln to maintain proper humidity inside the kiln. This
phase was not a really drying phase. Temperature was measured and used by the control
system to switch to the next phase. In the second phase wood was dried to the final MC. After
the drying phase timber was cooled down and conditioned at the programmed temperature. At
this temperature MC-sensors can be used to confirm that the final MC was achieved. Those
three phases comprised the drying schedule. The duration of those phases depends on the
wood species and its thickness. For pine (Pinus sylvestris L.) the third phase was the longest
while for oak (Quercus robur L.) the second phase lasted the longest. The oak samples were
dried in three different patterns: air, steam with a manual control and steam with an automatic
control (tab. 1). Pine lumber was dried only with an automatic control in cases of both prisms
and boards.
In the sawing experiments the frame sawing machine applied PRW15M, which works
with a kinematic system having an elliptical trajectory of the teeth movement. The driving
system is dynamically balanced and it guarantees that no contact of the saw teeth with the kerf
bottom occurs [7 Wasielewski and Orlowski]. Data of the machine tool: number of the saw
frame strokes nF = 685 rpm, stroke of the saw frame HF = 162 mm, feed speed at two levels
vf | 0.2 m min-1 and vf | 1.0 m min-1, m = 5 number of saws in the gang, and average cutting
speed vc = 3.69 m s-1. Data of saw blades with stellite tipped teeth which were employed in
the tests: overall set (kerf) St = 2 mm, saw blade thickness s = 0.9 mm, a free length of the
saw blade L0 = 318 mm, blade width b = 30 mm, tooth pitch P = 13 mm, tool side rake angle
Jf = 9q, tool side clearance angle Df = 14q. Blocks and lumber (a set of 3 pieces) stacks made
of pine (Pinus sylvestris L.) of Hp = 70 mm in height, with MC as in tab. 1 were cut. Prisms
made of oak (Quercus robur L.) of Hp = 70 mm in height, with MC as in tab. 1 were sawed.
The above mentioned data was the set of input values and the average value of the cutting
power P c was the output value. The mean value of total power P cT and the idling power P i
of the main driving system were measured with a power transducer. The latter was determined
directly before each cutting test. In computation of fracture toughness (specific work of
fracture) and shear yield strength it was assumed that in the case of oak friction coefficient is
equal to ȝ = 0.8 and for pine ȝ = 0.6.
Table 1. Drying patterns, initial and final MC for oak and pine samples
Comments
-
Final MC
before sawing
[%]
9.7
58
13
10.2
31 hours
47
7
6.8
Water nozzles
directed on
wood
Water nozzles
directed on
exchanger
Appr. 2
month
58 hours
25
-
6.5–9.8
24
13
9.5–10.3
72 hours
25
12
7.2–9.4
Drying time
Initial MC
[%]
Final MC in
kiln [%]
Appr. 3
months
4 weeks
58
Oak / manual
control
Pine / air
Type of wood
and drying
pattern
Oak / air
Oak / system
control
Pine prism /
system
control
Pine board /
system
control
96
Water nozzles
directed on
exchanger
Water nozzles
directed on
exchanger
Figure 1 shows the comparison of fracture toughness R of pine and oak for both methods
of drying: natural and accelerated in the kiln. For both species it is observed a decrease in
fracture toughness as a result of accelerated drying.
Fig. 1. Comparison of fracture toughness R of oak and pine, where: N – natural drying in air, AD – accelerated
drying in the kiln
The comparison of shear yield strength of pine and oak for both methods of drying:
natural and accelerated in the kiln is presented in fig. 2. For both species it is observed a
decrease in shear yield strength caused by the accelerated drying.
Fig. 2. Comparison of shear yield strength of pine and oak for both methods of drying: natural (N) and
accelerated (AD) in the kiln
97
CONCLUSIONS
Although the sawing process is not a pure example of orthogonal cutting, the application
of the results obtained by experimental cutting allowed us to determine toughness (specific
work of fracture) and shear yield strength of the sawn wood. Obtained results revealed that
accelerated drying of pine and oak conducted in the experimental kiln, according to the drying
patterns as is shown in tab. 1, caused a decrease of wood mechanical properties such as
fracture toughness and shear yield strength.
REFERENCES
1. W.F. Gard, High temperature drying on industrial scale. 1st Workshop “State of the art
for kiln drying”: Advances in drying of wood, Edinburgh, 1999.
2. M. WIERZBOWSKI, J. BARA SKI, J. ST SIEK, Gas-steam mixture wood drying.
In proc. of: COST E53 Meeting ''Quality Control for Wood and Wood Products'':
EDG Drying Seminar ''Improvement of Wood Drying Quality by Conventional and
Advanced Drying Techniques'', Bled, Slovenia, April , 2009.
3. Y. Patel, B.R.K. Blackman, J.G. Williams, J.G., Measuring fracture toughness from
machining tests. Proc. IMechE Vol. 223 Part C: J. Mechanical Engineering Science,
2009, pp 2861–2869.
4. A.G. Atkins, Toughness and cutting: a new way of simultaneously determining ductile
fracture toughness and strength. Engineering Fracture Mechanics, Vol 72, 2005, pp
849–860.
5. K.A. Orlowski, A. Atkins, Determination of the cutting power of the sawing process
using both preliminary sawing data and modern fracture mechanics. In: Proceedings of
the Third International Symposium on Wood Machining. Fracture Mechanics and
Micromechanics of Wood and Wood Composites with regard to Wood Machining,
21–23 May, Lausanne, Switzerland. Eds. Navi P., Guidoum A. Presses Polytechniques
et Universitaires Romandes, Lausanne. 2007, pp 171–174.
6. K.A. Orlowski, B. Pa ubicki, Recent progress in research on the cutting process of
wood. A review COST Action E35 2004–2008: Wood machining – micromechanics
and fracture”. Holzforschung, Vol 63, pp181–185.
7. R. Wasielewski, K. Orlowski, Hybrid dynamically balanced saw frame drive. Holz als
Roh- und Werkstoff, Vol 60, 2002, pp 202–206.
Streszczenie: OkreĞlanie wybranych wáaĞciwoĞci mechanicznych drewna suszonego z
uĪyciem pary wodnej na podstawie mocy skrawania. W niniejszym artykule przedstawiono
wyniki wi zko ci oraz napr e granicznych przy cinaniu drewna suszonego z u yciem pary
wodnej na podstawie zmierzonych warto ci mocy skrawania. Badaniom poddawano próbki
d bowe oraz sosnowe pochodz ce z pó nocnych regionów Pomorza. Wykazano, e
przyspieszone suszenie drewna z u yciem pary wywo uje obni enie badanych w a ciwo ci
mechanicznych, które wyznaczano z wykorzystaniem wspó czesnej mechaniki p kania.
Gdansk University of Technology, Faculty of Mechanical Engineering, Department of Manufacturing
Engineering and Automation, Narutowicza 11/12, 80-233 Gdansk, Poland
E-mail address: [email protected] (Kazimierz Orlowski)
The prediction method of the shear angle in the cutting zone during wood
sawing
K. A. ORLOWSKI1, T. OCHRYMIUK2
1
The Szewalski Institute of Fluid-Flow Machinery, Polish Academy of Sciences, Department of Transonic Flows
and Numerical Methods, Fiszera 14, 80-952 Gdansk, Poland
2
Abstract: The prediction method of the shear angle in the cutting zone during wood sawing. In this paper the
prediction method of the shear plane angle versus uncut chip changes has been presented. The shear plane angle
was forecasted with the use of modern fracture mechanics. A nonlinear equation, describing the shear angle as a
material dependent value, was solved numerically with the use of iterative Newton-Raphson method. Obtained
results of forecasting of the shear plane angle broaden possibilities of energetic effects modelling of the sawing
process even for small values of the uncut chip.
Keywords: wood sawing, shear angle, fracture mechanics, Newton-Raphson method
INTRODUCTION
Theoretical and experimental determination of values of forces acting in the cutting process
belongs to the basic and simultaneously the most developed field of mechanics of this
process. Analyses of cutting forces may be carried out with the classical approach to the
cutting energy Ec , which is composed of deformation and shear energy E)c , friction energy
at the rake face EJ, friction energy at the flank face ED, surface energy for the formation of
new surfaces EW and kinetic energy due to chip deflection EM [1 Grotte and Antonsson]. As a
result of that energetic effects (cutting forces and cutting power) are calculated on the basis of
the specific cutting resistance kc (cutting force per unit area of cut) [1 Grotte and Antonsson, 2
Orlicz]. On the other hand, cutting forces could be considered from a point of view of modern
fracture mechanics [3 Atkins]. The latter was applied for prediction of cutting power during
sawing on the sash gang saw [4 Orlowski and Atkins]. The value of the shear angle c,
present in the mentioned model which, defines the orientation of the shear plane with respect
to cut surface (fig. 1), may be calculated for larger values of feed per tooth fz with the classical
Merchant’s equation (because for large uncut chip values c = const., as shown in Atkins’s
paper (2003). In this paper, the prediction method of the shear angle for the whole range of
uncut chip changes, even for small values, is going to be presented.
Nomenclature
fz – feed per tooth, m
w – the width of orthogonal cut equal to St (overall set, kerf), m
Fa – active force, N
Fc – cutting force, N
Ff – thrust force (passive), N
FP – friction force on the rake face, N
FN – normal force to the rake face, N
FT) – the force required to shear the wood along the shear plane, N
FN) – normal force on the shear plane, N
R –specific work of surface separation/formation (fracture toughness), Jm-2
Z – the parameter which makes c material dependent
Įf – clearance angle, rad
ȕȝ – friction angle given by tan-1ȝ = ȕȝ, rad
Ȗ – the shear strain along the shear plane
99
Ȗf – rake angle, rad
ȝ – friction coefficient
ĲȖ – the shear yield stress, Pa
)c - shear angle, rad
THEORETICAL BACKGROUND
Making an assumption that cutting force Fc acting in the middle of the cutting edge is an
equilibrium of forces related to the direction of primary motion for a single saw tooth the
mechanical process of material separation from the sawn workpiece, i.e. chip formation, can
be described by the example of an orthogonal process (two dimensional deformation) [4
Orlowski and Atkins, 5 Orlowski and Palubicki]. The forces acting on the tooth can be
represented in the classical approach by Ernst and Merchant’s force circle shown in fig. 1.
D
J
FP
EP
FN)
EPJf
FT)
)c
FN
Fc
fz
Fa
Ff
Fig. 1. Simplified cutting process model with Ernst and Merchant’s force circle [1 Grotte and Antonsson]
Atkins (2003, 2009) proved that for least force Fc the shear angle ĭc satisfies:
ª
º ª
sin E P sin ) c
1
1 º
2 »
«1 »« 2
E
J
J
J
cos(
)
cos(
)
cos
(
)
sin

)
)
) c ¼»
» ¬«
P
f
c
f ¼
c
f
¬«
(1)
ª sin E P
° cos ) c
sin ) c sin() c J f ) ½°º
cot ) c tan() c J f ) Z «
¾»
®
E
J
J
cos(
)
cos(
)
cos2 () c J f ) °¿¼»
)
°̄
f
c
f
P
¬«
>
@
in which:
Z
R
(2)
WJ fz
is the parameter which makes c material dependent. The solution of nonlinear equation (1)
f(x) = 0 (x = fz, f = )c) cannot be found by the use of analytical functions, therefore was
necessary to solve it numerically using the iterative Newton-Raphson method [7 Press et al., 8
Tjalling]. The initial point of computations is very important and decides about convergence
of the solution. In this case the value of the shear angle was calculated from Ernst and
Merchant equation as an initial point has been assumed:
100
)c
(S / 4) (1 / 2)( E P J f )
(3)
The computational program has been created in the Fortran language.
FORECASTING OF THE SHEAR ANGLE
Prediction of the shear angle has been carried out for the case of sawing on the sash gang
saw PRW15M [9 Orlowski]. The indispensable data for computation (presented in table 1)
was determined according to the methodology described in the work by Orlowski and Atkins
(2007). Values of friction coefficients (tab. 1) were taken from the work by Beer (2002).
Table 1. Sawn material data R and ĲJ, friction coefficient P and tooth rake angle Jf
ĲJ
kPa
27417
22636
R
Jm-2
892
397
Wood species
oak
pine
P
Jf
–
0.8
0.6
deg
9
9
Obtained results of predictions of the shear plane angle c vs. fz of cutting models that
include work of separation in addition to plasticity and friction in the case of sawing dry pine
and oak on the sash gang saw PRW15M are presented in fig. 2.
40
Shear angle ) c [deg]
35
30
25
20
15
oak
10
pine
5
0
0.00
0.10
0.20
0.30
0.40
0.50
Feed per tooth f z [mm]
Fig. 2. Predictions of shear plane angle
c vs. fz in the case of sawing dry pine and oak wood on the sash
gang saw PRW15M
CONCLUSIONS
Obtained results of forecasting of the shear plane angle for the cutting models being
derived from the modern fracture mechanics, which include work of separation in addition to
plasticity and friction, broaden possibilities of energetic effects modeling of the sawing
process even for small values of the uncut chip.
101
REFERENCES
1. K.H. GROTTE, E.K. ANTONSSON (Eds.), Springer Handbook of Mechanical
Engineering, Part B: Applications in Mechanical Engineering. Chapter 7.3: Machining
Processes. Springer, 2008: 606–656.
2. T. ORLICZ, Obróbka drewna narz dziami tn cymi, wyd. VI, Skrypt SGGW-AR,
Warszawa, 1988.
3. A.G. ATKINS, Modelling metal cutting using modern ductile fracture mechanics:
quantitative explanations for some longstanding problems. International Journal of
Mechanical Sciences, 45(2003):373–396.
4. K.A. ORLOWSKI, A. ATKINS, Determination of the cutting power of the sawing
process using both preliminary sawing data and modern fracture mechanics. In:
Proceedings of the Third International Symposium on Wood Machining. Fracture
Mechanics and Micromechanics of Wood and Wood Composites with regard to Wood
Machining, 21–23 May, Lausanne, Switzerland. Eds. Navi, P., Guidoum, A. Presses
Polytechniques et Universitaires Romandes, Lausanne, 2007, 171–174.
5. K.A. ORLOWSKI, B. PALUBICKI, Recent progress in research on the cutting
process of wood. A review COST Action E35 2004–2008: Wood machining –
micromechanics and fracture, Holzforschung, 63(2009):181–185.
6. A.G. ATKINS, The science and engineering of cutting. The mechanics and process of
separating, scratching and puncturing biomaterials, metals and non-metals,
Butterworth-Heinemann is an imprint of Elsevier, Oxford, 2009, 413 p.
7. W.H. PRESS; B.P. FLANNERY; S.A. TEUKOLSKY; W.T. VETTERLING,
Newton-Raphson Method Using Derivatives. In: Numerical Recipes in FORTRAN:
The Art of Scientific Computing, 2nd ed. Cambridge, England: Cambridge University
Press, 1992, 355–362.
8. J. YPMA TJALLING, Historical development of the Newton-Raphson method. SIAM
Review, 37(1995)4, 531–551.
9. K. ORLOWSKI, Materia ooszcz dne i dok adne przecinanie drewna pi ami. Seria
Monografie nr 40, Wydawnictwo Politechniki Gda skiej, Gda sk 2003.
10. P. BEER, Obróbka skrawaniem obwodowym drewna nowo opracowanymi
narz dziami.. Roczniki Akademii Rolniczej w Poznaniu, Rozprawy Naukowe, Zeszyt
330. Wydawnictwo Akademii Rolniczej im. Augusta Cieszkowskiego w Poznaniu,
Poznan, 2002, 108 p.
Streszczenie: Metoda prognozowania kąta Ğcinania w strefie skrawania podczas przecinania
drewna. W niniejszym artykule opisano metod przewidywania k ta cinania w strefie
skrawania dla przypadku przecinania drewna. K t cinania by okre lany z wykorzystaniem
wspó czesnej mechaniki p kania. Nieliniowe równanie opisuj ce t wielko
by o
rozwi zywane numerycznie za pomoc metody iteracyjnej Newton-Raphson. Otrzymane
wyniki oblicze wykazuj mo liwo
rozszerzenia obszaru modelowania efektów
energetycznych procesu przecinania drewna nawet dla niewielkich warto ci warstwy
skrawanej.
Specific cutting resistance while sawing of wood – the size effect
K. A. ORLOWSKI1, T. OCHRYMIUK2, A. ATKINS3
1
2
The Szewalski Institute of Fluid-Flow Machinery, Polish Academy of Sciences, Department of Transonic
Flows and Numerical Methods, Fiszera 14, 80-952 Gdansk, Poland
3
University of Reading, School of Construction Management and Engineering, Whiteknights, PO Box 217,
Reading, Berkshire, RG6 6AH, United Kingdom
Abstract: Specific cutting resistance while sawing of wood – the size effect. In this paper results of analyses of
cutting resistance changes for the cutting models being derived from modern fracture mechanics, which include
work of separation in addition to plasticity and friction are presented. Those analyses are conducted for the
sawing process on the sash gang saw PRW15M of ash and thermally modified ash. The applied approach
allowed us to explain the increase phenomenon of the specific cutting resistance for small depths of cut as a ‘size
effect’.
Keywords: wood sawing, specific cutting resistance, size effect
INTRODUCTION
Energetic effects (cutting forces and cutting power) of wood sawing process are generally
calculated on the basis of the specific cutting resistance kc (cutting force per unit area of cut [1
Fischer, 2 Scholz et al.], which is in the case of wood cutting the function of the following
factors: wood species, cutting direction angle (cutting edge position in relation to wood
grains), moisture content, wood temperature, tooth geometry, tooth dullness, chip thickness
and some others which are less important [3 Agapov, 4 Orlicz]. It is well known that the
value of cutting pressure depends heavily on the thickness of the cut (uncut chip thickness)
[5 Atkins], which in the case of sawing equivalent is the mean value of feed per tooth f z [6
Ettelt and Gittel, 4 Orlicz, 7 Orlowski and Grzeskiewicz]. The variability of cutting pressure
in a function of the mean uncut chip thickness ought to be taken into account in computations
for small values of the cut for sash gang saws and bandsaws, and of course in modelling of
circular sawing processes, milling or planing, in which variation arises from the process
kinematics. Scholz et al. (2009) reported that there are a few mathematical approaches so far
known that try to take into account, in more or less simplified way, the effect of specific
cutting resistance changes vs. uncut chip thickness. However, neither of those theories
explains the causes of that anomalous behaviour.
On the other hand, cutting forces (power) could be considered from a point of view of
modern fracture mechanics [5 Atkins]. In this paper, on the basis of “the size effect” [5
Atkins] that is observed also in wood sawing for small depths of cut [7 Orlowski and
Grzeskiewicz] is going to be presented.
Nomenclature
fz – feed per tooth, m
kc – specific cutting resistance (cutting force per unit area of cut), MPa
w – the width of orthogonal cut equal to St (overall set, kerf), m
Fcw – cutting force per one tooth during the working stroke, N
R –specific work of surface separation/formation (fracture toughness), Jm-2
St – overall set, theoretical kerf, m
ȕȝ – friction angle given by tan-1ȝ = ȕȝ, rad
Ȗ – the shear strain along the shear plane
Ȗf – rake angle, rad
103
ȝ – friction coefficient
ĲȖ – the shear yield stress, Pa
Ĭshear – the friction correction
)c - shear angle, rad or deg
THEORETICAL BACKGROUND
On the assumption that every saw tooth of the plain shape is symmetrical and sharp, and
may have contact with the kerf bottom only during the working stroke of the saw frame, and
moreover, the feed per tooth has a uniform distribution in this stroke, the mean cutting force
in the working stroke is F cw for a single tooth of one saw blade. According to the cutting
model [5 Atkins, 8 Orlowski and Atkins] is given by:
ªW J S t J
RSt º
fz «Q
»
Q
shear ¼
¬ shear
F cw
(1)
where Qshear is the friction correction:
Qshear
[1 (sin E P sin ) c / cos( E P J f ) cos() c J f )]
(2)
If the Atkins’s model [5, 2009] Eq. (1), which includes fracture toughness R, is recast into
specific cutting resistance kc relationship, we obtain:
kc
Fcw
St f z
R·
1 §
¨¨W J J ¸¸
Qshear ©
fz ¹
(3)
At small depths of cut the so-called ‘size effect’ in metal cutting occurs [5 Atkins]. The
presence of ‘size effect’ is also visible in case of sawing, where at small values of fz
decreasing, an increase of kc occurs [8 Orlowski and Grzeskiewicz]. Thanks to application of
the cutting force model, which bases on the modern fracture mechanics, it is now clear that
R
term on the right hand side the specific cutting resistance must increase at small
with the
fz
fz. Furthermore at small values of fz, ĭc decreases and J increases [5 Atkins]. Changes in ĭc
and J vs. fz will be presented in the next subsection.
THE CASE STUDY
In figure 1 plots of cutting power per one saw and specific cutting resistance kc in a
function of feed per tooth fz during sawing on the frame sawing machine PRW15M with
narrow kerf saw blades (overall set St = 2 mm) of ash and thermally modified ash samples are
presented [8 Orlowski and Grzeskiewicz].
It has been found out that the thermal modification of ash wood causes a decrease of the
specific cutting resistance in comparison to unmodified one. Furthermore for both kind of
samples an increase at small fz has been observed [8 Orlowski and Grzeskiewicz]. Orlowski
and Grzeskiewicz [8, 2009] have not explained what was the reason of that phenomenon,
however, following the a discussion in the previous subsection, it can be said that what is
observed is a pure example of the ‘size effect’.
104
b)
a)
Specific cutting resistance kc , MPa
900
Cutting power Pc , W
800
700
600
500
400
300
ash
tm ash
200
100
0
0
0.1
0.2
0.3
200
180
160
140
120
100
80
60
40
ash
tm ash
20
0
0.4
0
0.1
Feed per tooth f z , mm
0.2
0.3
0.4
Feed per tooth f z , mm
Fig. 1. Cutting power per one saw (a) and specific cutting resistance (b) in a function of feed per tooth during
sawing on the frame sawing machine PRW15–M with narrow kerf saw blades (overall set St = 2 mm)
of ash and thermally modified (tm) ash samples [8 Orlowski and Grzeskiewicz]
On the basis of the experimental data shown in fig. 1a, with the fracture mechanics
applied (methodology described by Orlowski and Atkins (2007)), the following material data
was calculated for dry ash: fracture toughness is equal to R = 354 J m-2 and shear yield
strength is equal to ĲȖ = 33220 kPa; and for thermally modified ash R = 1090 J m-2 and ĲȖ =
19350 kPa. These values were used for numerical determination of shear angle )c, with the
method proposed by Atkins [9, 2003] (fig. 2a), and the shear strain along the shear plane Ȗ
(fig. 2b). For lower values of feed per tooth the second term of Eq. (3) plays an increasing
role, however, for larger values of feed per tooth its significance rapidly decreases and the
main resistance comes from the first term (fig. 3a, b).
b)
a)
35
shear strain J
shear angle )c [deg]
40
30
25
20
15
ash
10
tm ash
5
0
0.00
0.10
0.20
0.30
0.40
0.50
10
9
8
7
6
5
4
3
2
1
0
0.00
ash
tm ash
0.10
0.20
0.30
0.40
0.50
feed per tooth fz [mm]
feed per tooth fz [mm]
Fig. 2. Comparison of predictions of cutting models that include work of separation in addition to plasticity and
friction in the case of sawing dry ash and thermally modified ash on the sash gang saw PRW15M (a) shear plane
angle c vs. fz, (b) primary shear strain vs. fz
b)
a)
600
Cutting resistance [MPa]
Cutting resistance [MPa]
600
500
400
First
Second
300
kc
200
100
0
500
400
300
First
Second
200
kc
100
0
0
0.1
0.2
0.3
0.4
0.5
0
Feed per tooth fz [mm]
0.1
0.2
0.3
0.4
0.5
Feed per tooth fz [mm]
Fig. 3. Cutting resistance in the case of sawing dry ash (a) and thermally modified ash (b) on the sash gang saw
PRW15M vs. fz with its distribution on terms of the Eq. (3), where: First – plot of the first term, Second – plot of
the second term, kc – cutting resistance
105
CONCLUSIONS
Analyses of changes in cutting resistance predicted by the cutting models derived from
modern fracture mechanics, which include work of separation in addition to plasticity and
friction, allowed us to explain the reasons for the increase in cutting pressure for small values
of feed per tooth. At small depths of cut the so-called ‘size effect’ in wood sawing occurs
which is accompanied with the simultaneous changes of shear plane angle and primary shear
strain.
REFERENCES
1. R. FISCHER, Micro processes at cutting edge – some basics of machining wood. In:
Proceedings of the 2nd International Symposium on Wood Machining, Vienna,
Austria, 2004, pp. 191–202.
2. F. SCHOLZ, R. DUSS, R. HASSLINGER, J. RATNASINGAM, Integrated model for
the prediction of cutting forces. In; Proc. of 19th International Wood Machining
Seminar. Handong Zhou, Nanfeng Zhu, Tao Ding (editors), October 21–23, Nanjing,
China, Nanjing Forestry University, Nanjing, 2009, 183–190.
3. A.I. AGAPOV, Dinamika processa pilenija drevesiny na lesopil´nych ramach. (In
Russian: Dynamics of wood sawing on frame sawing machines). Kirovskij
Politechni eskij Institut, Izdanije GGU, Gor´kij, 1983.
4. T. ORLICZ, Obróbka drewna narz dziami tn cymi. Skrypty SGGW-AR
w Warszawie, Wydawnictwo SGGW-AR, Warszawa, 1988.
5. A.G. ATKINS, The science and engineering of cutting. The mechanics and process of
separating, scratching and puncturing biomaterials, metals and non-metals,
Butterworth-Heinemann is an imprint of Elsevier, Oxford, 2009, 413 p.
6. B. ETTELT, H.J. GITTEL, Sägen, Fräsen, Hobeln, Bohren. Die Spanung von Holz
und ihre Werkzeuge. DRW-VerlagWeinbrenner GmBh & Co.KG, 2004.
7. K. ORLOWSKI, M. GRZESKIEWICZ, The effect of heat treatment of hardwood on
the specific cutting resistance. Annals of Warsaw University of Life Sciences SGGW. Forestry and Wood Technology. - 2009, No 69, 147-151.
8. K.A. ORLOWSKI, A. ATKINS, Determination of the cutting power of the sawing
process using both preliminary sawing data and modern fracture mechanics. In:
Proceedings of the Third International Symposium on Wood Machining. Fracture
Mechanics and Micromechanics of Wood and Wood Composites with regard to Wood
Machining, 21–23 May, Lausanne, Switzerland. Eds. Navi, P., Guidoum, A. Presses
Polytechniques et Universitaires Romandes, Lausanne, 2007, 171–174.
9. A.G. ATKINS, Modelling metal cutting using modern ductile fracture mechanics:
quantitative explanations for some longstanding problems. International Journal of
Mechanical Sciences, 45(2003):373–396.
106
Streszczenie: WáaĞciwy opór skrawania podczas przecinania drewna – efekt skali. W
artykule przedstawiono wyniki analiz zmian w a ciwego oporu skrawania, przy zastosowaniu
wspó czesnej mechaniki p kania z uwzgl dnieniem wi zko ci. Analizy wykonano dla
procesu przecinania drewna na pilarce ramowej PRW15M drewna jesionu i jesionu
modyfikowanego termicznie. Zastosowane podej cie pozwala na wyja nienie zjawiska
wzrostu w a ciwego powierzchniowego oporu skrawania dla niewielkich grubo ci warstwy
skrawanej jako efektu skali, a nie zmian w a ciwo ci materia u obrabianego.
Technological aspects of electronic systems production on wood-based
PCBs
B. PA UBICKI1, M. SZULC2, M. SYDOR1
1
2
University of Life Sciences, Faculty of Wood Technology, Pozna , Poland
Poznan University of Technology, Faculty of Computer Science and Management, Pozna , Poland
Abstract: Technological aspects of electronic systems production on wood-based PCB. In this paper the
preliminary results of wood based panels applicability as printed circuit boards (PCB) are presented. HDF and
plywood were tested for their thermal resistance while melting the soldering paste located on wood based PCB.
Wood based PCB need some more time and energy, then conventional PCB, to allow solder paste to melt. HDF
requires longer preheating than plywood, but they are more stable in shape.
Keywords: Printed Circuit Board, wood based PCB, soldering, PCB recycling
INTRODUCTION
The Printed Circuit Boards (PCB) are bases for almost all electronic systems used around
the world. It supports electronic elements like: resistors, capacitors, diodes, integrated circuits,
microchips etc. It also provides conduction thru designed conductive traces to ensure their
functionality.
There are few types of PCB construction. The simplest is based on fiber reinforced epoxy
resin covered on one or both sides with conductive copper pattern [1]. Elements might be
mounted on PCB – SMD (Surface Mount Device) or loomed through holes in the PCB and
soldered on the other side – THT (Through-Hole Technology). In both cases there are many
techniques of soldering but oven reflow soldering is one of most popular and cost effective
for today’s solutions [2].
Nowadays PCBs fulfill most of operational requirements. However, they cause some
difficulties at the end of their life cycle. Some works are known on recycling of epoxy PCB
[3], but still disassembling (i.e. removing functional electronic elements from the PCB) is
annoying.
For this reason it was decided to verify the possibilities of replacing epoxy PCB with Wood
Based Printed Circuit Boards (WBPCB) which are easy degradable in high temperature or
biologically by controlled fungi attack. In that case used electronic system could be easily
disintegrated with negligible impact on the environment.
There are several mechanical and electrical requirements that a new base for PCB has to
fulfill, but the first step to verify usability of wood based materials in electronic systems is
their resistance to high temperatures. This is because the first step in PCB utilization is
soldering the set of electronic components on it. Usually this is performed in a dedicated
convection reflow oven following the pre-defined temperature profile reaching 250°C. This is
rather high temperature for wood or wood based materials, so it requires verification is it
applicable.
Present work is a preliminary study on technological aspects and possibilities of producing
WBPCB. Its aim is to verify thermal resistance of WBPCB, needed in soldering process.
108
As a possible replacement for conventional epoxy PCB, the following materials have been
taken into consideration (table 1). The specimens of dimensions 150 x 100 mm were kept in
normal conditions and at the time of experiment the moisture content was in the range of 4,8 –
6,2 %. No special surface finishing, fire retardant nor decay protection treatment was applied
in order to ensure easy and eco-friendly post utilization degradation.
Table 1. Examined wood based materials characterization
Thickness
(mm)
3,05 ± 0,03
3,05 ± 0,04
2,92 ± 0,02
2,88 ± 0,01
1,92 ± 0,01
2,15 ± 0,04
2,61 ± 0,04
4,22 ± 0,01
Material
HDF (company 1)
HDF (company 2)
HDF (company 3)
HDF (company 4)
Plywood 1 (3-layer hardwood)
Density
(kg/m3)
839 ± 5
903 ± 45
869 ± 29
892 ± 5
645 ± 10
761 ± 6
770 ± 13
753 ± 4
On each specimen of WBPCB a self-adhesive copper foil (conductive layer) was applied.
Then a piece of AIM Solder NC257 SN100C solder paste [4] was put on it. Samples were
then put into convection lead-free reflow oven – LPKF ProtoFlow (fig. 1).
Fig. 1. Convection Lead-Free Reflow Oven used in experiments
In order to melt the solder paste a specific temperature is needed, in current case the melting
point of used solder paste is 227°C. In regular soldering process there are at least four phases
of process: 1) oven worm-up (without PCB), 2) preheat - to heat up the whole system (PCB
with electronic components and soldering paste), 3) reflow – apply the temperature peak and
then 4) cool-down the PCB. This entire soldering process (profile) is designed to melt the
solder paste without over-heating the electronic elements.
109
According to [4] the specific heat capacity of different wood in normal conditions is about
1,4 kJ·kg-1·K-1, when e.g. for glass reinforced epoxy laminates FR-4 it is about 0,6 kJ·kg-1·K-1
[5]. It means that wood (or wood based materials) need more energy to increase temperature
to required level. Due to this it is necessary to elongate the preheat phase. The effect of
soldering the WBPCB was verified for: 100, 150, 250, 300, 350 and 400s of preheating.
Soldering profile used in current experiment is shown (without worm-up phase) on the figure
2.
Reflow
Preheat duration
Fig. 2. Soldering profile with 150 s of preheating
After thermal treatment the specimens were visually inspected in order to verify if the
solder was melt and then for each type of wood based panel the minimal preheat time was
pointed out causing full melting of solder. The deformation of each WBPCB was rated
qualitatively.
The high temperature causes darkening of the boards surfaces – it was measured by means
of reflected light intensity measurement before and after heating. The darkening was
evaluated as light intensity difference divided by native intensity of surface.
RESULTS
In current experiment the main criteria which determines a usability of wood based material
in PCB application was whether the solder paste was melted or not. Figure 3 shows the
difference.
Fig. 3. Solder after WBPCB heating: a) well soldered joint, b) not fully melted solder
110
On the figure 4 the minimal preheat duration is presented, which in overall process has
leaded to solder paste melting and creating high quality soldered joint. For each type of wood
based panels an appropriate duration was found except for HDF 2 and Plywood 4 for which
even 400 s did not give a good result. It might be stated that both cannot substitute epoxy
PCB, because longer preheat time may lead to fire start and in real process to electronic
elements over-heat. For the rest of samples the minimal duration has been found. In general
HDFs needed more time to heat up than plywood sheets. Assuming quite constant specific
heat capacity for wood biomass [6] one may explain this by higher density of HDF and
therefore higher mass of specimens to be heat-up.
Fig. 4. Minimal preheat time at 170°C at the process causing solder to melt
In the scope of preheat time plywood has shown up to be better than HDF, but on the other
side plywood seems to have inclinations to bend during heating. Thin plywood (1,9-2,6 mm)
quite easily heats up to the melt point of solder paste but its twisting and bending disqualify it
as a PBC base. Thicker plywood (4,2 mm) remains quite flat but, as it was mentioned, during
experiments it was impossible to melt the solder paste, even while preheated for 400 seconds.
HDF specimens have remained flat except of ones from producer 1 which showed small
deformations.
25
Surface darkening (%)
Plywood 1
20
HDF 1
15
10
5
0
0
50
100
150
200
250
300
350
400
Preheat phase duration (s)
Fig. 5. Chosen WBPCB surface darkening after complete heating process with different phase duration
111
Figure 5 shows the surface darkening of two WBPCB; both plots stops at minimal duration
of preheat phase (compare figure 4). It is visible that HDF even preheated for longer time
(350 s) increase its darkening for maximum 5% while plywood preheated for only 100 s
darkens for 7,5% and after 150 s for over 20%. A steep slope of plywood curve – intensive
specimen darkening, might be caused by outstanding wood fibres which locally achieve
higher temperatures than plywood in mass, causing burning. HDF colour is more resistant to
heat because it has no outstanding fibres and because it is much darker before heating.
During this experiment WBPCB heating has never caused any fire, but it has to be
mentioned that intensive evaporating and gasification had place in some cases, especially
when longer preheat time were applied.
SUMMARY
The results obtained in these preliminary studies are promising. In general it might be stated
that considering thermal resistance some WBPCB might take place of conventional epoxy
PCB. They require however adopting soldering profiles and extra anti-fire care (e.g. the
company LPKF producer of ProtoFlow oven delivers solution of heating in the nitrogen
atmosphere).
LITERATURE:
1. C.T. ROBERTSON, Printed circuit board designer's reference: basics, Pearson
Education Inc., Upper Saddle River, USA, 2004
2. C.F. COOMBS, Printed Circuits Handbook, McGraw-Hill, 2007
3. W. KORNACKI, Recycling p ytek drukowanych, Recykling 2 (2004) P. 24
4. AIM SOLDER, Website: http://www.aimsolder.com, accessed on 02.09.2010
5. BOLTON UNIVERSITY MATERIALS, Website:
http://www.ami.ac.uk/courses/ami4817_dti/u01/supplementary/sup_02.html, accessed
on 02.09.2010
6. WOOD HANDBOOK, Wood as an Engineering Material. General Technical Report
FPL-GTR-190. Forest Products Laboratory, 2010
Streszczenie: Technologiczne aspekty produkcji ukáadów elektronicznych na páytkach z
tworzyw drzewnych W artykule opisano wst pne wyniki bada u yteczno ci p yt
drewnopochodnych do produkcji pytek obwodów drukowanych (PCB). P yty HDF i sklejki
by y badane pod wzgl dem ich odporno ci temperaturowej podczas topienia lutu.
Drewnopochodne p ytki PCB potrzebuj wi cej czasu i energii do stopienia pasty lutowniczej
ni standardowe PCB. P yty HDF wymagaj d u szego czasu wygrzewania wst pnego ni
sklejki, ale ich kszta t jest bardziej stabilny.
Bartosz Pa ubicki, University of Life Sciences, ul. Wojska Polskiego 28, 60-637 Pozna , Poland
E-mail address: [email protected]
Analysis of web page creation technologies used on websites of selected
kitchen furniture manufacturers
TOMASZ PARYS
Department of Technology, Organisation and Management in Wood Industry, Faculty of Wood Technology,
Warsaw University University of Life Sciences (SGGW)
Abstract: Analysis of web page creation technologies used on websites of selected kitchen furniture
manufacturers The paper presents some of the technologies used to build websites with a short description of
each of them Presented are the criteria by which web services of kitchen furniture manufacturers were selected.
The main part of the study provides an analysis of those sites in terms of technologies used in their construction.
The article also contains a synthetic discussion of got results.
Keywords: website creation technologies, kitchen furniture manufacturers, web services.
INTRODUCTION
In recent years the Internet from the phenomenon of an information society, as even a
decade ago was referred to, became a regular feature of daily life. At the beginning of the XXI
century, the Internet is a tool used not only by people who want to quickly and smoothly to
communicate, but also by companies and firms seeking to establish and maintain
communication with the market and thus sell products and services, and thus to survive in
conditions of increasing competition. The main tool of communication are web pages. They
should be built using modern technologies that allow the proper display of pages, and thus an
appropriate reception published on their content. Analysis of use of these technologies has
been devoted to this paper.
SELECTED WEB PAGE CREATION TECHNOLOGIES
HTML
HyperText Markup Language is the main web content description language. It is one of
the oldest and thus one of the most widespread website development technologies. HTML is a
parsed language, i.e. basing on tags, the web browser displays (builds) an image of a
particular web page. Its feature, non-existing in any other programming language, is that it
does not generate errors and potential mistakes made in the code are simply ignored [3].
Web pages coded in HTML are plain text files, which means that they do not contain any
information intended for a specific application or platform. They are readable in any flat text
editor. HTML files contain the proper text to be displayed on the web page and tags used for
marking up elements of that page as well as its formatting structure and links to other web
pages and multimedia elements [2]. This is a document description language - it contains a set
of tags describing its structure, layout and formatting of various objects on the page. This
language is also independent of the hardware and software platform,
XHTML
The specification of the XHTML (eXtensilble HyperText Markup Language) does not
describe any tags. It only defines changes, which shall be introduced to a HTML document,
113
so that it becomes a XHTML document. In practice, there are very few differences between
XHTML and HTML. The differences are only limited to several formal requirements, which
include: the requirement that tag names are written only in lowercase and the requirement to
place parameter names between quotation marks. A correctly constructed XHTML document
is de facto compatible with the XML specifications. XHTML-compatible documents, require
validation, i.e. checking whether they are actually compliant with that specifications. XHTML
documents must be unanimously interpreted by other users without any problems. This is in
the interest of every user, as the standard is used in general e-commerce (e.g. by Internet
shops).
XML
The XML (eXtesible Markup Language) consists only of some core expressions. While
creating an XML document, contrary to HTML no fixed set of tags is used. Instead, custom
tags are defined, which can be assigned with any name. Therefore XML is also described as
an extendable programming language. This is where the power and the flexibility of XML
comes from, as this formats allows to simply store any data. By separating the text from the
form, one may focus on the data itself. XML is in practice a group of script languages
compatible with requirements of that specifications. By using a common XML format, normal
programs can easier exchange data and the information published can be more easily
processed. This language permits overcoming the compatibility gap between many computer
systems, allowing their users to quickly and more easily search for and exchange various
types of data [5].
JAVASCRIPT
JavaScript is a client-side scripting language, which adds interactive features to web pages
and permits website developers to control various aspects of web browser operation.
JavaScript allows additional link information to be displayed, development of effects related
to mouse cursor movements, altering web page contents according to a pre-set conditions,
random generation of web page content, loading content into new web browser windows and
frames and repositioning of elements on the web page using CSS. Name of the JavaScript
language is only incidentally similar o the name of Java programming language. Despite some
similarities in the syntax of Java to JavaScript, in order to learn JavaScript one does not need
to know Java. JavaScript allows to add various options to a web page using short snippets of
code, with easy to understand syntax [3]. JavaScript allows elements and effects, which are
not supported by a plain HTML – such as forms or animations to be included on web pages.
CSS
Cascading Style Sheets (CSS) are an extension, which is helpful in web page development.
Style sheets allow authors to apply typographic styles and instructions to elements of a web
page. The word “cascading” determines what happens when several sources of style
information compete over an element of a web page. Using style sheets provide greater
control over the web page layout and at the same time allows separation of the web page
content from its structure. Using style sheets, it is possible to specify traditional attributes,
such as font size or inter-line and inter-character spacing. Style sheets also provide methods
for determining indentations, margins and positions of elements. Multiple HTML pages can
be linked to a single style sheet. This means that not only a single change may be made, that
will effect each copy of the respective element on one web page, but also it is possible to
114
apply changes on hundreds or thousands of web pages by editing a single line of a style sheet
only. [3] The goal of CSS creators was to combine flexible means of web page styles control
and means for controlling individual elements on web pages with a relevant style hierarchy
[1].
PHP
PHP (Hypertext Preprocessor) is a simple to learn language, which offers exceptional
performance, tight integration with almost any database system used, stability, portability and
almost unlimited options for web pages development. This language is an open source
solution, which means it is free of charge. The goal of PHP is to allow web developers to
rapidly write dynamically-generated web pages. It is used for dynamic image generation and
for data encryption purposes [7]. The PHP language is a server-side language, which means
that the code in that language is stored on the host computer serving a web page to users
wishing to view it. At the time when a user enters a web page written in PHP, the server reads
instructions in this language and processes them accordingly. The code executed by the server
sends its output to the web browser, in the form of a HTML code.
FLASH
Flash technology permits to create a line-art animation. It allows a motion sequence, with
accompanying sound track to be created, which is also referred to as movie. The advantage of
Flash is the very process of movie and line art generation, which is automated. Also,
animations created in Flash are considerably light weight. Flash presentations can be included
on a web page or can act as a web page [ref. 4]. Thanks to advanced scripting capabilities,
application of Flash presentation is only limited by developers’ imagination.. It's significant
advantage is scalability, as line art pictures and animations can be zoomed-in without loss of
fine detail, which causes that it is quire easy to fill the whole browser window with a Flashscripted interface without causing the source file to grow too much. The Flash technology
includes, designed specially for its purposes, object-oriented programming language called
ActionScript. It is responsible for communicating with external files - both for file reading
and writing - for communication with database and for handling all Flash events [ref. 6].
ASP.NET
ASP.NET (Active Server Pages NETwork) is a component of the Microsoft.NET
Framework platform, permitting development, deployment and execution of network
applications and distributed applications. It is free of charge technology, which can be used
for creation of small applications, private websites as well as large commercial applications.
ASP.NET is a technology, which allows to easily create dynamic web pages and to manage
them. It is the latest generation of the original ASP technology, providing multiple
improvements and extensions. ASP has made development of web sites cooperating with
databases a very easy task. However it lacked features of advanced programming languages,
such as object-oriented programming, complex code, portability, XML network services and a
class library designed specially for the Internet or language architecture.
115
CRITERIA
FOR
WEBSITES
MANUFACTURERS
SELECTION
OF
KITCHEN
FURNITURE
When selecting sites for this analysis was guided by the companies a variety of criteria that
the sample was the most diverse. Selected furniture manufacturers offering furniture form
both materials wood and wood-based (panel). Among these were next to the large and well
known throughout the market, producers, and small companies operating locally, including
carpentry workshops, family services in the field of furniture manufacturing. Were also
represented manufacturers of finished furniture offered in both forms : as the series and to
order. The group analyzed sites in addition to sites that have been qualified with the
manufacturers only offer kitchen furniture manufacturers and other types of furniture. In the
selection has been taken into account the geographical location of the manufacturer, so that
the companies represented various regions of our country. Websites were divided into two
groups. The first one are the web services of manufacturers, which offer only kitchen
furniture. The second one is the group of producers which offer more types of furniture.
Analysis was performed on 42 websites. In the first group were fourteen, in the second
twenty-eight web services. Internet addresses of selected websites are given in Table 1.
ANALYSIS OF WEB PAGE CREATION TECHNOLOGIES ON WEBSITES OF
SELECTED KITCHEN FURNITURE MANUFACTURERS
The following table presents results the services of kitchen furniture manufacturers
analysis in terms of technologies used for their development. The table presents the state as of
beginning August 2010, when it was performed. During the analysis, it has been assumed
that a website does not use HTML if its code was compatible with XHTML. However use of
XML by websites has only been indicated, when that specification was used, in addition to
XHTML language, e.g. to handle RSS data feeds. The Internet addresses of the websites in
the table below were arranged in alphabetical order (in each group).
PHP
FLASH
ASP.NET
-
116
Java Script
+
+
+
+
-
XML
+
+
+
+
+
XHTML
Manufacturers offering only kitchen furniture
www.atlas-kuchnie.com.pl
+
+
+
www.bb.meble.pl
+
+
+
www.bik-meble.pl
+
+
+
+
www.domuskuchnie.pl
+
+
+
www.elprim-wika.com.pl
+
+
+
www.krups.pl
+
+
+
www.laura.com.pl
+
+
+
www.meblekam.pl
+
+
+
www.meble-niko.pl
+
+
+
Website address
HTML
CSS
Table 1: Web page creation technologies on websites of selected kitchen furniture manufacturers
www.medom.com.pl
www.ofm-sa.com.pl
www.prestiz.net.pl
www.stokan.pl
www.vizualform.pl
+
+
+
+
+
+
+
+
+
+
+
+
+
+
Manufacturers offering many kinds of furniture
+
+
+
www.anna.net.pl
+
+
+
www.arinohouse.pl
+
+
+
www.brw.com.pl
+
www.extrameble.com
+
+
+
+
www.forte.com.pl
+
+
+
www.halidor.pl
+
+
+
+
www.ikea.pl
+
+
+
www.jagstol.pl
+
+
+
www.kuchnie-wolsztyn.eu
+
+
+
www.kulenty.home.pl
+
+
www.laminat.waw.pl
+
+
+
www.matmeble.com
+
+
+
www.meblegolab.pl
+
+
+
www.mebleklos.pl
+
+
+
www.meblelokator.pl
+
+
+
www.meblemalecki.pl
+
+
www.mebleproducent.waw.pl
+
+
www.mebleprojekt.com
+
+
+
www.meble-s.com.pl
+
+
+
www.meblocross.pl
+
+
+
www.megameble.com
+
+
+
www.mestol.pl
+
+
www.saganmeble.dzs.pl
+
+
+
www.slonex.pl
+
+
+
www.stoland.pl
+
+
+
www.stol-pol.pl
+
+
+
+
www.taurus.pl
+
+
+
www.wojtasmeble.pl
+
+
+
-
+
+
+
-
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
-
source : own research
Most of the analyzed websites was built using XHTML (twenty-eight). The most popular
technologies was Javascript and CSS. Only six did not use Javascript, however CSS is not
used in only one website. Using of technologies PHP and FLASH was while not popular.
PHP technology was used in twenty-two cases. FLASH technology was present in twenty-two
websites too (There were not the same web service). Note that XML technology was used
117
only in four sites, but none benefited from ASP.NET. It is hard to identify the leader of this
analysis. You can specify the site, which was the least technologically advanced. It was the
website available under address www.extrameble.com. This web service was created by using
only HTML. It should be noted also that the HTML as outdated technology is still often used
by web designers. The HTML was used in websites developing in fourteen cases.
CONCLUSION
The analyzed websites of kitchen furniture producers were created using the different
technologies, which contributed to their apparent visual attractiveness and that their correct
displaying (interpreting) in all popular web browsers. The only postulate that can be report to
authors and administrators of these web services could be to introduce more variation to
forms of the published content presentation.
REFERENCES
1.
2.
3.
4.
CROWDER D., CROWDER R., 2005: Tworzenie stron WWW, Helion, Gliwice.
LEMAY L., 2004: HTML i XHTML dla ka dego, Helion, Gliwice.
NIEDERST J., 2002: Tworzenie stron WWW, Helion. , Gliwice,
PARYS T., 2009: Flash - modern tool to create WEB-based e-business resources [w:]
Chmielarz W., Parys T. (red.), Technologie informacyjne dla spo ecze stwa,
Wydawnictwo WSE-I, Warszawa 2009, str. 285-290.
5. PARYS T., 2007: J zyk XML przyk adem standardu przesy ania danych w e-biznesie,
[w:] Zastosowanie systemów e-biznesu w gospodarce, Chmielarz W., Parys T. (red.),
Wydawnictwo WSE-I, Warszawa, str. 277 - 288.
6. PARYS T., 2008: Zastosowanie technologii Flash w e-biznesie na przyk adzie
reklamy internetowej [w:] Uwarunkowania zastosowa systemów e-biznesu w
gospodarce, Chmielarz W., Parys T., Wydawnictwo WSE-I, Warszawa, str. 205-221.
7. ULLMAN L., 2006: PHP i MySQL Dynamiczne strony WWW, Helion, Gliwice.
Streszczenie:: Analiza technologii kreowania stron internetowych wykorzystanych w
witrynach wybranych producentów mebli kuchennych W opracowaniu przedstawiono
wybrane technologie wykorzystywane do budowy witryn internetowych, z krótkim opisem
ka dej z nich. Zaprezentowano kryteria na podstawie których wybrane zosta y witryny
internetowe procentów mebli kuchennych. Zasadnicz cz
opracowania stanowi analiza
tych e serwisów pod k tem technologii wykorzystanych do ich budowy. W artykule
zamieszczono tak e syntetyczne omówienie uzyskanych wyników.
S owa kluczowe: technologie budowy witryn internetowych, producenci mebli kuchennych,
serwis internetowy
Tomasz Parys
Department of Technology,
Organization and Management in Wood Industry,
Faculty of Wood Technology,
Warsaw Agricultural University (SGGW)
02-776 Warsaw,
ul. Nowoursynowska 159
Website creation script technologies – a comparative analysis of
compatibility with the W3C standards in Polish furniture industry portals
and vortals
TOMASZ PARYS
Department of Technology, Organisation and Management in Wood Industry, Faculty of Wood Technology,
Warsaw University of Life Sciences (SGGW)
Abstract : Website creation script technologies – a comparative analysis of compatibility with the W3C
standards in Polish furniture industry portals and vortals In this article were presented standard organizations
working on the needs of Internet. and introduced the basic script technologies used to building of web pages for
which exist standards defined by the organization W3C. It shows a short profile of portals and the vortals from
the furniture industry, which were chosen and analyzed. The main part of this paper is the analysis of compliance
of technologies used to the building of these services with standards, which were defined by W3C organization.
This article contains the synthetic discussion of got results and recapitulation.
keywords: W3C standards, website creation script technologies, furniture industry, internet portal and vortal
INTRODUCTION
In the last years, the Internet has transformed from ‘the information society phenomenon’,
as it was called a dozen years ago, into a permanent element of everyday life. Using the
Internet is just necessary, and not only suggested. Internet is a global network used by people
from different countries and different cultures and speaking different languages. This fact is
the reason for the permanently increasing importance of standardisation for communication
tools, www sites being a perfect example thereof. This article concentrates on compatibility of
script technologies used for developing furniture industry websites, with standards.
STANDARDS ORGANISATIONS IN THE INTERNET
In the Internet, not a single standard is valid, which would be imposed by any body1. Yet,
in practice, several organisations are active determining Internet operation specifications and
standards. Besides W3C, such best known bodies are:
x IETF (Internet Engineering Task Force) - An informal international society of individuals
interested in determination of technical and organisational standards for the Internet. The
IETF does not dispose of any formal power, still, it is just the IETF work outcomes that
have decisive effects on the future Internet shape. The IETF generates a special set of
documents, so-called RFC (Request For Comments) containing the entire Internet wisdom
in questions and answers, which means: - technical and organisational standards creating
this network. The IETF is open for new participants, any interested individual may access.
x ISO (International Organization for Standardisation) - A non-governmental organisation
for local standardisation bodies. ISO members are not delegated by governments despite
some ISO member organisation being incorporated in government structures. Strategic
decisions are made by the General Assembly during its annual meetings.
1
The only standard adopted as required and commonly used on the Internet is the set of TCP/IP protocols.
Without this protocol support installed, computers can not connect with Internet.
119
Standardization of the documents in the Internet is an issue of a high importance. As in the
entire information technology, documents in the Internet must be interpreted unambiguously.
No room for any conjecture as to the document content. Standards for script technologies as
applied for construction of websites are worked out by the W3C organization shown below.
W3C - WORLD WIDE WEB CONSORTIUM
This organization is active in the area of determination of standards for construction of
WWW sites, transmission, and interpretation thereof by browsers. The organisation was
founded 1994 by Tim Berners-Lee, the originator of WWW services who also created the
very first Internet browser. At present, the W3C member list contains more than 400
organisation, companies, governmental agencies, and universities from all over the world.
The W3C is divided in numerous discussion teams for defined tasks. Teams are composed of
experts from W3C members, whereas members are companies and all types of organisations
interested in the establishment of the standard involved. Standards (called
‘recommendations’) published by the W3C have no legal power, which could impose the use
thereof but the very influence of the organisation can not be omitted. The organisation makes
available tools for verifying the code (HTML, XML, CSS) compliance with the defined
standard. Such tools were applied for carrying out the analysis used in this paper.
CHARACTERISTICS OF ANALYZED TECHNOLOGIES
HTML
This language is listed among the oldest technologies designed for website construction.
As such, HTML is the basic and commonly applied technology. HTML consists of markup
tags: commands in angle brackets such as <A>, with parameters added. HTML is an
interpreted language: the browser displays (builds) the website based on markup tags, by their
sequence in the file describing the involved site. HTML has a specific feature: errors are not
generated - that statement is false for all the other programming languages. Any error in the
HTML code is ignored [2]. That feature makes influence on the content of the displayed page,
but does not give reason to stop displaying. HTML (Hypertext Markup Language) is a
document description language - a set of markup tags describing the document structure as
well as object location and formatting within the site. Besides, HTML is independent of the
equipment and software platform. A site-describing file is an ordinary text file - that is the
reason that the file can be edited in any text editor. At present, the HTML standard2 is not
under development because the work concentrates on XHTML, with the new HTML version
complying with the XML specification3. A conclusion can be drawn that a majority of
individuals creating their own websites started their Internet adventure a similar way - from
learning the HTML programming software.
XHTML
2
Information can be found on the Internet and in some references that work is under way on HTML version 5 see http://www.knowmore.pl/internet/html5-nowy-standard - the cited information was available on 28 July
2010.
3
XML (eXtensible Markup Language) – another standard developed by W3C. Instead of applying defined
markup tags, designers may create own markup tags with any name. That is the place of origin for XML power
and universality as the format for easy storage of any data.
120
The XHTML (Extensible Hypertext Markup Language) specification does not contain any
markup tag. The specification only defines the amendments necessary for a HTML document
in order to convert it into a XHTML document. In practice, a number of differences exist:
formal requirements, including the necessity to write markup tag names with small letters
only, and quotation marks for names. Documents written in XHTML must be univocally and
with no problem interpretable by other users, that is why they require so-called ‘validation’ - a
verification whether they really comply with the specification. Such validation is in every
user’s interest because this standard is widely used for e-commerce (e.g. web stores). The
specification defines three language dialects: strict, transitional, frameset (as for HTML). The
transitional4 dialect accepts element names written with small letters or capital letters;
quotation marks for attribute values are optional as closing some elements is. The strict
dialect is more restrictive than the transitional dialect. The requirement list for strict dialect
includes: closing of all the elements listed as ’closing optional’, double quotation marks for
attribute values, correct element embedding, and avoiding elements applied for visual text
formatting (colours, fonts types, bold characters, italics, etc. - those effects should be obtained
with application of CSS). Frameset - the third dialect - is only used for building the warp for
documents created with frames. At present, two standards have been defined: : XHTML 1.0,
XHTML 1.1, with the first one applied nearly in all cases. Work is under way from 2006 on
the specification version 2.05 - so far, no official standard has been published6.
CSS
CSS, or Cascade Style Sheets allow site designers to use typographic styles and
instructions for site elements. The sheets allow to determine traditional attributes such as font
size, line spacing, character spacing. Besides, style sheets provide with determination
methods for margin indents and element positions. A single style sheet can be connected with
numerous HTML sites - this solution guarantees that one modification is effective for each
copy of the involved element on just one site but also can be effective for hundreds or
thousands of sites [2]. The cascade style sheet designers had an objective of connecting a
flexible www site style control method and single elements within sites on one side with a
correct style hierarchy on the other side [1]. At present, CSS version 2 is valid und used.
SHORT VIEW ON WEB SERVICES FROM THE FURNITURE INDUSTRY
Polish web services dedicated to the furniture sector issues have a specific feature: a
majority of those services belong to furniture manufacturers or commercial companies
(furniture trading companies). This paper concentrates those services: portals and vortals. The
following portals and vortals were selected for analysis: www.meblarstwo.pl, www.meble.pl,
www.emebel.pl, www.meble.com.pl, www.4meble.pl, www.emeble.pl, www.infomeb.pl,
www.stolarstwo.pl, www.portalmeblowy.pl, www.nowemeble.pl, www.meblewpolsce.pl,
www.polskie-meble.pl, www.meblepolska.eu, www.euromeble.net. The range of the analysis
in this paper was expanded in the relation to the author’s previous works [ref. 3 and 4].
Those portals and vortals were analysed for compliance of the applied technologies with
W3C standards.
ANALYSIS OF SCRIPT TECHNOLOGY COMPATIBILITY WITH W3C STANDARDS
4
In Table 1, this dialect is marked as ‘Trans.’
Description can be found at www.w3.org/xhtml2 - (status of July 2010).
6
The 2.0 standard introduces numerous solutions resulting in incompatibility thereof with earlier versions.
5
121
The table below contains the analysis of code used in furniture portals and vortals:
compatibility of script technologies with W3C-defined standards. The analysis was made
based on validators available from: http://validator.w3.org - for HTML/ XHTML and
http://jigsaw.w3.org/css-validator - for CSS compatibility.
The compatibility criterion was the number of errors and suggestions7 reported by validators
for the sites under analysis. The analysis concentrated on source codes for websites belonging
to furniture portals and vortals. In case of HTML and XHTML, codes were compared to the
standard listed in the table; in case of CSS, the CSS2 standard was the reference point. The
table represents the state as of beginning August 2010, when the analysis was performed.
Table 1: Compatibility of script technologies with W3C standards for selected websites.
Site address
www.meblarstwo.pl
www.meble.pl
www.emebel.pl
www.meble.com.pl
www.4meble.pl
www.emeble.pl
www.infomeb.pl
www.stolarstwo.pl
www.portalmeblowy.pl
www.nowemeble.pl
www.meblewpolsce.pl
www.polskie-meble.pl
www.meblepolska.eu
www.euromeble.net
Compatibility with standard
HTML, XHTML
CSS
Stated compatibility Errors Suggestions Errors Suggestions
XHTML 1.0 Trans.
14
3
38
471
XHTML 1.0 Trans.
34
9
250
1671
XHTML 1.0 Trans.
3
3
1
71
HTML 4.01 Trans.
114
58
15
76
HTML 4.01 Trans.
244
200
8
52
HTML 4.01 Trans.
29
17
2
144
XHTML 1.0 Trans.
11
0
11
207
XHTML 1.0 Trans.
77
4
25
845
XHTML 1.0 Trans.
63
9
2
57
HTML 4.01 Strict
11
3
3
173
HTML 4.01 Trans.
56
17
3
170
XHTML 1.0 Trans.
15
6
28
387
HTML 4.0 Trans.
59
106
3
164
HTML 4.01 Trans.
179
90
5
102
Source: own research
The above analyzed furniture industry portals and vortals were specific for, on one hand: a
high differentiation of their compliance level, and on the other hand: a low differentiation of
standard versions that their codes were compliant with. Among fourteen sites under analysis,
seven were prepared applying a standard HTML 1.0, and seven a standard XHTML. Only
one site applied a strict dialect of HTML 4.01 (www.nowemeble.pl). Not a single site was
built fully compliant with standards. This status should be ranked very unsatisfactory. The
highest compliance level of was that of the www.infomeb.pl site.
Indisputably, two sites, www.4meble.pl and www.meble.pl ranked lowest. For the first
site, the ‘HTML compatibility’ category reported 244 errors and 200 suggestions. For the
second site, the ‘CSS compatibility’ category reported 250 errors and as much as 1671
suggestions. This situation should be understood as designers’ negligence.
7
Both in their English version and Polish version, validators (in particular CCS validators) reported ‘errors’ and
‘warnings’ indicating departures from the standard. In this paper, ‘warnings’ are called ‘suggestions’ because in
the presented sites, validators suggested ways to remove the incorrect structures.
122
CONCLUSION
The furniture portals and vortals were designed with application of up-to-date HTML,
XHTML and CSS script technologies. Unfortunately, those sites rank low for compliance
with the script standards applied. Not a single site could prove a full compatibility with the
analyzed standards. Website designers from this sector still have a lot of work to do before
the sites are compliant with those standards.
REFERENCES :
1. CROWDER D., CROWDER R., Tworzenie stron WWW, Helion, Gliwice, 2003.
2. NIEDERST J. , Tworzenie stron WWW, Helion, Gliwice, 2002 .
3. PARYS T., Forms of internet advertising used in furniture industry portals and vortals
in Poland - Annals of Warsaw University of Life Sciences - SGGW, Forestry and
Wood Technology, No 69, Warszawa 2009.
4. PARYS T., Selected website development technologies used in furniture industry
portals and vortals in Poland , INTERCATHEDRA No. 25, Pozna 2009.
Streszczenie : Technologie skryptowe kreowania witryn internetowych - analiza
porównawcza zgodnoĞci ze standardami W3C w polskich portalach i vortalach branĪy
meblarskiej. W opracowaniu przedstawiono organizacje standaryzacyjne dzia aj ce na
potrzeby Internetu oraz podstawowe technologie skryptowe budowy stron internetowych, dla
których istniej standardy zdefiniowane przez organizacj W3C. Zasadnicz cz
artyku u
stanowi analiza zgodno ci technologii wykorzystanych do budowy tych e serwisów z
standardami wyznaczonymi przez organizacj W3C. Zamieszczono tak e syntetyczne
omówienie uzyskanych wyników oraz krótkie podsumowanie.
S owa kluczowe : standardy W3C, technologie skryptowe budowy witryn, bran a meblarska,
portal i vortal internetowy,
Tomasz Parys
Department of Technology,
Organization and Management in Wood Industry,
Warsaw Agricultural University (SGGW)
02-776 Warsaw,
(Ann. WULS-SGGW, For. and Wood Technol. 72, 2010)
Relationship between the anatomical structure elements and physical
properties in the trunk transverse and longitudinal direction for wood of
Norway spruce (Picea abies (L.) Karst.) growing in Latvia
GUN RS PAVLOVI S, J NIS DOLACIS, ANDIS ANTONS, DACE C RULE
Latvian State Institute of Wood Chemistry
Abstract. The aim of the present work was to characterise the relationship between the main anatomical
structure parameters and physical properties of spruce wood. The main anatomical structure parameters under
study were: annual ring width (Gp ), share of late wood in the annual ring (Gvk%), tracheid length (TL), double
wall thickness and cross-section in radial direction in early wood (T 2w ak, TR ak) and late wood (T2W vk, TR vk).
The main characteristics of the physical properties were as follows: wood density ( o), volume swelling ( v) and
shrinkage ( v), linear swelling in radial ( rad) and tangential ( tg) directions, linear shrinkage in radial ( rad) and
tangential (ßtg) directions, water (W ) and moisture absorption (Wm) values. These physical characteristics, as
well as the anatomical structure elements, were determined at four trunk heights (at the butt-end – R, ¼, ½ and ¾
parts of the trunk height, which corresponds to the trunk’s relative lengths 0, 25, 50 and 75%, respectively), and
in the radial direction from heart pith to sapwood. The tracheid length decreases in the direction from the trunk’s
butt-end to the top in longitudinal and radial direction from sapwood to heart pith. Thus, for example, the
tracheid length ratio in the direction from sapwood to heart pith is 1.31, ¼ – 1.27, ½ – 1.23 and ¾ – 1.18. In
comparison with pine wood, the average tracheid length throughout the trunk’ length for spruce wood is higher
by 25% and is equal to 4.0 mm. The ratio of the early wood tracheid double wall thickness in the direction from
sapwood to heart pith in the trunk’s longitudinal direction and at the butt-end is 1.25, ¼ – 1.12, ½ – 1.13 and ¾ –
1.05. Hence, the location of the sample in the tree trunk is very important, because it influences the anatomical
parameters and physical properties of wood. For the first time, a comprehensive study on the distribution of the
anatomical elements and physical properties of wood in the trunk’s longitudinal and transverse direction, as well
as their correlation, was carried out. The distribution of spruce wood density in both sapwood and core in the
direction from the butt-end to the top decreases, which coincides with the higher content of late wood in the
annual ring and tracheid lengths in these trunk’s parts. The exception is ¾ from the trunk’s length, where the
density increases in both the core part and sapwood, because juvenile wood prevails at such a trunk’s height.
Keywords: Norway spruce, anatomical structure, physical properties
INTRODUCTION
Although Norway spruce (Picea abies (L.) Karst.) is the third dominant tree species in
Latvia, there is no exhaustive information about the relationship between its structure and
physico-mechanical properties, and anatomical structure elements. Up to now, a whole range
of studies on the anatomical structure and physical properties of spruce wood have been
carried out (BALODE et al. 1999, 2002, 2004; HROLS et al. 2005; PRIEDKALNS et al. 2002;
POLUBOJARINOV 1976). However, their changes throughout the height and radius of the trunk have
not been determined.
The present work is the first comprehensive study on the relationship between the
anatomical elements of spruce wood grown in Latvia and its mechanical properties, both
throughout the length of the trunk and in the transverse direction, as well as their correlative
interrelationships.
124
For mutual comparison of the obtained data, determination of the anatomical
parameters and physical properties of wood in the same trunk’s site was proposed as the task
of the study. In practice, it is difficult to obtain sample trees of identical dimensions for
mutual data comparison. Therefore, in the present work, the sample tree trunk was divided at
proportional heights (butt-end – R, ¼, ½ and ¾ from the trunk height).
The trunk’s cross-section is schematically represented in Fig. 1. To determine the
physical properties, the samples were chosen in the transverse direction (samples’ transverse
sizes 20 × 20 mm, length – 10 mm) from the heart pith to sapwood (Fig. 2).
Figure 1. Schematic representation of Figure 2. Determination of the physical
trunk sampling.
properties numeration in the trunk
sample’s cross-section.
The original direction of the samples’ numeration was accepted from heart pith to
sapwood (0 or 1 in the centre and further, depending on the sample’s diameter 2, 3, 4.... n).
To avoid the variation in the properties of natural wood among different trees, one
pine tree was used in our experiment. Probably, this limits the number of experimental data,
and definite conclusions on the relationships between the anatomical structure elements and
physical properties cannot be made based on one tree’s data. In the present study, the first
attempt was made to show at least tendencies in looking for such relationships.
To investigate the anatomical parameters of wood, a special optical microscope
MTK -1 with a video camera TK-C721EG (JVC Color) was used, employing the software
IMAGE-PRO EXPRESS for picture analysis in reflected light. The physical characteristics of
wood were determined in accordance with the following standards (DIN 52 182, DIN 52 184,
GOST 16 483.18 – 72). The tracheid length distribution throughout the trunk’s height and in
the transverse direction determines many physical characteristics of spruce wood.
125
The values of the anatomical parameters of spruce wood are shown in Table 1.
Table 1. Values of spruce wood anatomical parameters
Part of
trunk,
H
buttend, R
1/4
1/2
3/4
A,
cm
TR vk,
mkm
TR ak,
mkm
T 2w vk,
mkm
T 2w ak,
mkm
TL,
mm
Gvk,
%
Gpl,
mm
16
10
6
10
7
4
8
6
4
23.0
22.9
23.3
21.3
21.4
20.8
19.8
19.7
19.4
40.8
39.9
38.7
40.3
39.0
36.9
38.9
37.1
36.4
13.3
12.4
11.1
11.6
11.8
10.1
10.9
10.6
10.2
5.9
5.1
4.7
4.6
4.6
4.1
4.4
4.2
3.9
4.6
3.8
3.5
4.7
4.4
3.7
4.2
4.1
3.4
28.0
24.6
23.6
20.3
20.8
12.8
14.0
14.6
12.2
1.51
1.58
2.27
1.03
1.11
1.87
1.04
1.17
1.48
5
3
19.5
18.6
36.5
35.1
9.9
9.5
4.1
3.9
4.0
3.4
13.7
9.3
1.25
2.10
Legends: H – relative height of the trunk; A – distance from the pith; TR vk – diameter of late wood tracheids; TR
– diameter of early wood tracheids; T 2w vk – double cell wall width of late wood tracheids; T 2w ak – double cell
wall width of early wood tracheids; TL – tracheids length; Gvk – late wood percentage in the annual ring; Gpl –
width of annual rings, mm.
ak
Values of the spruce wood density and physical properties are shown in Table 2.
Table 2. Values of spruce wood density and physical properties
H,
%
R
1/4
1/2
3/4
o,
g/cm3
W ,%
K ,%/%
Tg
S
H
0.38 0.34
0.41 0.39
0.38 0.38
0.37 0.22
Ra
S
0.496
0.479
0.443
0.517
H
0.484
0.458
0.440
0.448
S
168
180
198
159
H
S
H
172 0.13 0.13
191 0.17 0.17
197 0.16 0.15
177 0.17 0.09
Wm, %
V
S
0.53
0.60
0.56
0.57
H
0.48
0.58
0.55
0.32
S
16.8
16.8
16.8
17.0
H
16.9
16.7
16.8
17.1
Legends: H – height of the trunk; o – density of oven dry wood; W – water absorption; K (Ra, Tg, V) –
coefficient of swelling (radial, tangential, volumetric); Wm – moisture absorption; S – sapwood; H – heartwood
The spruce wood density ( o) distribution at the butt-end and ¼ from the trunk’s
height throughout the trunk’s radius (A) is shown in Fig. 3. It can be seen that the density at
the top’s end in the direction to sapwood grows more dramatically than in the trunk’s central
part. The spruce wood density ( o) distribution at ½ and ¾ from the trunk’s length throughout
the trunk’s radius (A) is shown in Fig. 4.
0,60
0,60
0,55
1, R 2 = 0,1369
4, R2 = 0,392
3
0,50
1
2
0,45
ȡ0, g/cm
ȡ0, g/cm
3
0,55
3
4
0,45
3, R2 = 0,0591
0,40
2, R 2 = 0,5314
0,40
0,50
0,35
0,35
0
5
10
15
0
20
Figure 3. Distribution of density ( o)
on the spruce trunk radius: 1 – R, 2 – ¼.
2
4
6
8
10
12
A, cm
A, cm
Figure 4. Distribution of density ( o)
on the spruce trunk radius: 3 – ½ un ¾.
126
The tracheid length and the distribution of the late wood content throughout the trunk
height and the transverse direction determine many physico-mechanical characteristics of
spruce wood. The longer the tracheids and the greater the content of late wood in the annual
ring, the higher is the density and the greater is the swelling coefficient.
CONCLUSIONS
1. The tracheid length in the direction from the trunk’s butt-end to the top in the
transverse and radial direction from sapwood to heart pith decreases. Thus, for
example, the tracheid length ratio in the direction from sapwood to heart pith is
1.31, ¼ – 1.27, ½ – 1.23 and ¾ – 1.18.
2. The ratio of the early wood tracheid double wall thickness from sapwood to heart
pith in the longitudinal direction decreases and is equal to 1.25, ¼ – 1.12, ½ – 1.13
and ¾ – 1.05 at the butt-end. However, the ratio of the late wood tracheid double
wall thickness in the direction from sapwood to heart pith in the trunk’s
longitudinal direction decreases not so dramatically as in early wood, and is equal
to 1.20, ¼ – 1.15, ½ – 1.07 and ¾ – 1.04 at the butt-end. The ratio of the share of
late wood in the direction from sapwood to heart pith varies according to another
regularity, reaching the maximum ratio ¼ from the trunk’s height (1.19, ¼ – 1.59,
½ – 1.15 and ¾ – 1.47 at the butt-end).
3. The distribution of spruce wood density, both in sapwood and heart pith, decreases
in the direction from the butt-end to the top, which agrees with the greater lengths
of the late wood content in the annual ring and the tracheid lengths in these parts
of the trunk. The exception is ¾ from the trunk length, where density grows, both
in the heartwood part and sapwood, because juvenile wood prevails at this height
of the trunk.
4. The distribution of spruce wood density in the oven dry state in the trunk’s
transverse direction from heart pith to sapwood is positive. At the butt-end and at
½ from the trunk’s length, it is insignificant (r = 0.37 and 0.24, respectively).
However, it is essential at ¼ and ¾ from the trunk’s length (r = 0.73 and 0.63,
respectively).
REFERENCES
1. BALODE V., ALKSNE A., DOLACIS J., HROLS J., 2002: Some elements of
the anatomical structure of spruce wood growing in Latvia. – Annals of
Warsaw Agricultural University. Forestry and Wood Technology. Special
Number I. Warsaw: 19 – 24.
2. BALODE V., CIRULE D., DOLACIS J., HROLS J., KRUTUL D., KAZEMBEK D., 2004: Morphological and physical properties of Norway spruce
(Picea abies Karst.) wood growing in Latvia. – Annals of Warsaw Agricultural
University – SGGW, Forest and Wood Technology, No. 55, 26 – 29.
3. BALODE V., DOLACIS J., CIRULE D., HROL J., 2004: Physical properties
of Norway spruce (Picea abies Karst.) wood growing in Latvia. – Proceedings
of IV International Symposium: “WOOD STRUCTURE, PROPERTIES AND
QUALITY’ 04”. St. Petersburg, RUSSIA, October 13 – 16, 2004, Vol. I, 178 –
180.
4. HROLS J., ALKSNE A., CIRULE D., DOLACIS J., BALODE V., 2005:
Anatomical structure and physical properties of spruce (Picea abies L. Karst.)
wood in Latvia. – Proceedings of LAU, Jelgava, 14 (309), 65 – 71 (in Latvian).
5. PRIEDKALNS G., PUSHINSKIS V., DOLACIS J., HROLS J., 2002:
127
Physico-mechanical properties of spruce wood growing in Latvia. –Annals of
Warsaw Agricultural University. Forestry and Wood Technology. Special
Number I. Warsaw, 33 – 37.
6. POLUBOYARINOV O. I., 1976: Wood density, Lesnaya Promishlennost’,
Moscow, 160 pp. (in Russian).
Streszczenie. Zale no
pomi dzy struktur anatomicz i w asno ciami fizycznymi a
po o eniem w osi i na rednicy pnia wierka (Picea abies (L.) Karst.) rosn cego na otwie.
Celem niniejszej pracy jest wykazanie zale no ci pomi dzy struktur anatomiczn i
w asno ciami fizycznymi drewna wierka. Rozpatrywano: szaeoko s oja rocznego (Gp ),
zawarto drewna pó niego w s oju (Gvk%), d ugo cewek (TL), grubo
ciany oraz
przekroju w kierunku promieniowym drewna wczesnego (T 2w ak, TR ak) and late wood
(T2W vk, TR vk). g ównymi wska nikami w asno ci fizycznych by y: g sto drewna ( o),
sp cznienie obj to ciowe ( v) skurcz obj to ciowy ( v), sp cznienie w kierunku
promieniowym ( rad) sp cznienie w kierunku stycznym ( tg) , skurcz w kierunku
promieniowym ( rad) skurcz w kierunku stycznym (ßtg), absorbcja wody (W ) i absorpcja
wilgotno ci (Wm). W asno ci fizyczne oraz anatomiczne by y mierzone w 0, 25, 50 i
75%,wysoko ci pnia oraz promieniowo od rdzenia do bielu. D ugo cewek zmniejsza si w
kierunkach od pnia w gór strza y oraz od rdzenia do bielu. Podobnie g sto drewna maleje
wraz z po o eniem w k odzie od pnia w gór strza y, wraz z mniejsz zawarto ci drewna
pó nego.
Latvian State Institute of Wood Chemistry,
Dz rbenes iela 27, Riga, LV-1006, LATVIA,
tel. +371 7553063, fax: +371 7550635,
Wooden houses and fire safety rules
K.PERZYNA , A. KOLBRECKI
Building Research Institute, Filtrowa Str. 1, 00-611 Warsaw, Poland
Abstract: Wooden houses and fire safety rules In this article, basic requirements regarding fire safety of
buildings, and the rules of fire classifications of building elements or products, have been presented. The specific
fire properties of building products, made of wood, have been discussed. In reference to technical and legal
regulations, the possibilities of fulfilling of such requirements by wood/wood based products have been
presented and in this connection, the influence on the investment process.
Keywords: buildings, fire safety, Polish buildings rules
Nomenclature
Reaction to fire – contribution of product, by one’s own decomposition, in fire reaction, exposed to the defined
conditions
Resistance to fire classification – conventional classification of the element of building in relation to the tested
specimen’s behaviour under normalized test conditions, taking in to account load bearing capacity R, insulation
capacity I, and integrity capacity R
Spreading of fire degree – conventional classification of the element of building, in relation to the tested
specimen’s behaviour under normalized conditions, taking into account spreading of flame on the surface of
tested specimen on inside the specimen, flameless combustion (smouldering) or thermal decomposition of
material of the specimen, occurring of flaming droplets/debris
Fire load density – thermal energy, expressed in MJ that can be released during combustion of combustible
material existing in the compartment, fire zone or solid materials’ storage per surface unit area of this object
expressed in square meters
Building should be designed and built in this way, that in case of outbreak of fire, the
evacuation should be possible, the spread of fire in the building and between buildings should
be limited and the construction of the building could not undergo destruction within a
specified time.
In the residential and public buildings, mainly during combustion of solid materials, the
course of the fire can be divided into 3 stages. In order to assess the behavior of building
products in a fire, the initiation and the first two stages of a fire are important. The initiation
can be caused by a number of reasons, such as inattention, negligence, faulty installation or
acted intentionally. Source of initiation has unspecified thermal parameters: like glowing
cigarette, basket of garbage or burning brand.
In the first stage (the temperature up to 800qC) fire is characterized by uniform
distribution of temperature, while the highest temperature occurs in the upper parts of the
room. In addition to the high temperature, the smoke containing toxic and irritating
substances appears. The main hazard in the first stage, besides the temperature, is fogging
(due to the spread of toxic, narcotic and irritant products) hindering the visibility, and
consequently the evacuation. With this stage of fire, the restrictions on the use of combustible
materials are related as well as requirements for their degree of flammability (reaction to fire)
and spread of fire by the elements.
In the second stage, rapid increase in temperature in the compartment (above 1000qC)
occurs. In this stage the fire, combustible building materials, regardless of their classification,
got burned along with other materials located in the compartment.
The degree of flammability (reaction to fire) shall be determined for combustible materials at
exposure levels corresponding to the effect of a small source of flame or single burning item.
129
The degree of fire spread is defined for the items tested on a scale similar to the natural and is
associated with the effect of the single burning items.
If we consider combustibles in a fire, it is important to differentiate between two groups:
- furnishings or materials stored in a room or building,
- building materials (including installations).
High temperature during the fire and fogging are generally caused by the combustion of the
first group of materials. They have a decisive part in the group of phenomena that are
associated with a fire in the compartment. The percentage of combustible construction
materials in full burnt materials during a fire is relatively small. Their calorific value is not of
great importance in the combustion. Fire hazard caused by the application of these materials
rely not on usually a significant part in heat balance, but the possibility of the spread of fire in
the building and accelerate the development of a fire. This follows from the fact that these
materials could have considerable geometrical dimensions, pass through many compartments
include a large plane and length. These materials occur in places where there are no
furnishings and other usable materials in the building. The fire can move between storeys
through the combustible facades and insulations, electrical equipment, ventilation ducts. To
some extent, one can speak about the effect of "cord", i.e. of such an effect, when burning the
material does not constitute an imminent threat, but may cause flashover in a distant part of
the building.
The principal feature of the wood, which distinguishes this material in a fire from
materials such as concrete or steel, is its flammability. As a result of combustion, a layer of
charred insulation is created. Thanks to its porous structure (as a result of thermal
decomposition of wood, only about 15% solids remains) the layer has low thermal
conductivity, several times smaller than the conductivity of coniferous wood. This layer
reduces oxygen supply to the non-charred core, and hence the temperature, which allows for a
while during a fire, load bearing by the wooden construction. Due to the nature of the
behavior of the wood, its burning and mechanical properties are discussed together, since they
are associated closely with the load capacity of the profile.
The properties of wood in the reaction to fire are affected by the physical properties and
use of fireproof impregnation or coating. The reaction to fire classification is assigned
according to PN-EN 13501-1 standard [2]. In the case of wood products, wall/ceiling and
floor products are classified separately.
In the technical rules of construction, products are divided on the combustible and noncombustible products. Wood, regardless of way of protection is always a combustible
material. Combustible products shall be divided into non-ignitable, hardly-ignitable and
ignitable. In addition to the division of products mentioned above one can divide products
into: do not spreading the fire, slightly spreading the fire and strongly spreading the fire.
Currently, the classifications of combustibility (ignitability) are replaced by the
classification of reaction to fire according to PN-EN 13501-1 [2]. The classification of the
spread of fire through the roofs is being replaced in the classification of the resistance on the
roof of the external fire PN-EN 13501-5 [3]. Relations between terms taken from the
technical conditions of construction and classifications according to PN-EN are given in [1].
The spread of fire through the outer surfaces of exterior wall is determined by the current
Polish standard [4] without reference to the classification according to PN-EN.
The requirements for the reaction to fire and fire spread are formulated because, under the
effect of a relatively small source of ignition (i.e. burning garbage bin, a burning firebrand)
building elements should not spread fire and smoke.
Wood and wood-based materials are combustible materials. But their reaction to fire
classifications can be improved by using appropriate fire-retardant agents to meet the
technical requirements of building regulations (and / or investor). Activity of fire protection
130
is to: a delay of ignition, reducing the rate of surface spread of flame, reducing the intensity of
combustion. Fire retardant agents, appear in the form of salt, paint or varnish, materials to
perform type of barrier layers.
In the developed fire, despite the fire-retarding, timber burns and thermal decompose.
The level of technical and regulatory requirements of the construction depends on the
destination of the building or compartment (category ZL, PM, or IN), building height, number
of people in the compartment, the fire load, the presence of passive fire protection means.
These are mandatory requirements, the general, without reference to the type of material used.
This paper does not discuss these requirements.
Fire properties in the range of fire spread on the external surfaces of the external walls
and roofs have an impact on the distance between buildings (table 1) [1].
Type of building and for the “PM”
building the maximum fire load density
Q, MJ/m2
ZL
IN
PM
(industrial-storage
building)
Q 1000
PM
1000<Q 4000
PM
Q>1000
Type of building
ZL
(threat
humans) [m]
8
8
8
15
20
to IN
(farm
building) [m]
8
8
8
15
20
The distances in the table, refer to the buildings with walls and roofs non-spreading the
fire; in case when one of the exterior walls that is located from the side of neighbouring
building or the roofing from one of the buildings is spreading the fire, the distance in the table
should be increased by 50% and, if this applies to both the external walls or roof roofs of both
buildings - about 100%. If the wall or roofing does not have a specific fire classification, it is
to be assumed that such element is strongly spreading the fire.
REFERENCES
1. Rozporz dzenie Ministra Infrastruktury z dnia 12 kwietnia 2002 r. w sprawie
warunków technicznych jakim powinny odpowiada budynki i ich usytuowanie (Dz.U
Nr 75, poz. 690 z pó niejszymi zmianami).
2. PN-EN 13501-1+A1: 2010 Klasyfikacja ogniowa wyrobów budowlanych i elementów
budynków Cz
1: Klasyfikacja na podstawie wyników bada reakcji na ogie .
3. PN-EN 13501-5+A1: 2010 Klasyfikacja ogniowa wyrobów budowlanych i elementów
budynków Cz
1: Klasyfikacja na podstawie wyników bada oddzia ywania ognia
zewn trznego na dachy.
4. PN-90/B-02867 + A1 Ochrona przeciwpo arowa budynków. Metoda badania stopnia
rozprzestrzeniania ognia przez ciany
Building Research Institute, Filtrowa Str. 1, 00-611 Warsaw, Poland
E-mail address: [email protected] (Kamil Perzyna)
Annals of Warsaw University of Life Sciences– SGGW
(Ann. WULS-SGGW, For and Wood Technol.72,2010
ɍɬɨɱɧɟɧɧɵɣ ɦɟɬɨɞ ɪɚɫɱɟɬɚ ɩɪɨɞɨɥɠɢɬɟɥɶɧɨɫɬɢ ɫɭɲɤɢ
ɩɢɥɨɩɪɨɞɭɤɰɢɢ ɜ ɧɢɡɤɨɬɟɦɩɟɪɚɬɭɪɧɵɯ ɤɚɦɟɪɚɯ
,
,
–
Abstract: Revised method of calculating the length of sawn timber drying in the low temperature chambers In
this article written about the need to clarify the existing method of determining the length of drying in the light
of features of the kinetics of the drying process in the “water” chambers. This is achieved by introducing an
additional source of moisture in the equation of moisture conductivity
Keywords: Wood drying, tabular method, duration of the drying process, “water” chambers, equation of
moisture conductivity.
–
.
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.
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,
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134
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f (W ɩɥ , DW , DS , Dv , DVt , DU , Dɤɚɱ , Dɲɬ )
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(4)
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REFERENCES
1.
4921:2008., 2009:
.
2.
. . 1975:
.:
.
- . 400
3.
. .,2010:
«
». 227 .
.
(
1-2008/39). 7 .
.
.
:
Streszczenie: Zmodyfikowana metoda wyliczeĔ czasu niskotemperaturowego suszenia
tarcicy. Artyku sugeruje potrzeb poprawy istniej cej metody wyznaczania czasu suszenia w
komorach wodnych, w wietle kinematyki procesu. Cel osi gni to wprowadzaj c dodatkowe
ród o wilgoci w równaniach przewodno ci wody.
Olena Pinchewska, Georgiy Inozemtcev, Andrii Spirochkin
Department of Wood Processing
National University of Life and Environmental Sciences of Ukraine,
Kyiv,vul.Geroiv Oborony 15,03041, Ukraine
[email protected]
Ɉɫɨɛɟɧɧɨɫɬɢ ɫɭɲɤɢ ɩɢɥɨɩɪɨɞɭɤɰɢɢ ɢɡ ɞɪɟɜɟɫɢɧɵ ɹɫɟɧɹ
,
,
–
Abstract: Sawn ash timber drying specifics. It is written about the field of use and the structure features of ash,
which have an influence on it’s moisture diffusivity. The results of experimental determination of ash basic
density, hygroscopicity limit and moisture diffusion coefficient are given. Using the moisture gradient existing
ash drying schedules are compared to determinate the most rational
Keywords: Sawn ash timber, moisture diffusion coefficient, drying schedule, moisture gradient
2,9 %,
.
,
.
,
,
.
,
,
,
. .
,
:
,
.
,
.
– Fraxinus excelsior L.,
.
,
.
.
1,4 %
,
,
–
,
.
,
.
,
.
.
,
150...250
,
,
.
–
,
.
,
,
.
,
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.
,
,
.
,
.
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85
136
[1].
.
:
– Wɩɟɪ.=30 %,
– Wɩɟɪ.=20 %.
,
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.
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,
.
1985
[2],
.
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25, 20
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,
(
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–
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[2].
.
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,
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,
,
.
25°C, 40°C, 60°C
.
Wɩ.ɝ. . (
80°C,
137
).
28,35 % (
,
34,71 %
. 1).
,
–
.
,
2
ɚǯ,
t, ºC,
:
/ ,
x
:
ɚ cɪ
x
( 2 ,1 ln t- 5 ,93 ) u 10 6 ,
:
ɚɬc
( 1,91 ln t-5 ,54 ) u 10 6 .
. 1.
Wɩ.ɝ.
.
,
1,2
,
,
,
(
.
=596
[3]
3
,
–
ɚǯ
[4])
. .
3
=550
.
.
,
10 %.
,
.
,
.
,
,
ĳ
t,
,
Wp,
Wɿ.
Gr,
[5]:
Gr³
Gr ɿ –
Wɿ –
Wɪ –
W³
Wð
;
, %;
, %.
138
:
Gr,
Wɪ
.
Wɿ
,
–
, Gr
.
–
ĳ–
t,
,
.
, Gr,
: 6- [1],
25
2 [2]
7- 3 [6].
. 2.
Wɿ t 40 %
Gr
,
.
,
, Gr
,
,%
. 2.
Gr
.
,
,
2,
,
.
6- ,
.
.
7- 3
Wɿ=40...20 %.
.
Wɿ
15-20 %
,
.
,
.
139
REFERENCES:
1.
. . 1976:
.:
.
- . 136 .
2.
. . 1990:
. .:
3.
. . 2001:
.
,
.
5.
.:
.
.
.
4.
,
. 464 .
.:
-
. 340 .
. . 1975:
.
- . 400 .
. . 2010:
. .:
. 228 .
6. Denig Joseph; Wengert, Eugene M.; Simpson, William T. 2000: Drying hardwood
lumber. Gen. Tech. Rep. FPL–GTR–118. Madison, WI: U.S. Department of Agriculture,
Forest Service, Forest Products Laboratory. 138 p.
Streszczenie: Specyfika procesu suszenia tarcicy jesionowej. Artyku prezentuje specyfik
drewna jesionowego i jej wp yw na przewodno wody. Zaprezentowano wyniki analizy
g sto ci, higroskopijno ci i wspó czynnika przewodno ci wody. Obecne procedury suszenia
tarcicy jesionowej zosta y porównane z u yciem gradientu wilgotno ci, w celu ustalenia
najlepszej.
Olena Pinchewska, Sergey Kompanetz, Rostislaw Olejnik
Department od Wood Processing
National University of Life and Environmental Sciences of Ukraine,
Kyiv,vul.Geroiv Oborony 15,03041, Ukraine
[email protected]
(Ann. WULS - SGGW, For. and Wood Technol., 72, 2010)
Quality of profile milling on a cnc woodworking machine
GRZEGORZ PINKOWSKI, WALDEMAR SZYMA SKI
Department of Woodworking Machinery and Basis of Machine Construction,
Abstract: Quality of profile milling on a cnc woodworking machine. The study presents investigations
concerning the processing quality of profile elements manufactured in the CNC processing centre. Experiments
were carried out on elements made of solid oakwood of a definite arrangement of annual rings using a cutterhead
with two sets of blades: sharp and worn. In the course of investigations, production processing parameters were
applied. Milling quality was determined by measurements and analyses of roughness parameters of the finished
surfaces using for this purpose a profilometer with appropriate equipment. Varying relationships were found
between the condition of the cutting edge and the roughness of the processed surface from the point of view of
annual ring distribution of wood and place of measurement.
Keywords: profile milling, surface roughness, CNC processing centre.
INTRODUCTION
One of the factors affecting product quality is its final processing. Rectilinear or
curvilinear processing is most commonly achieved by milling using, for this purpose,
numerically controlled woodworking machines which allow quick and accurate execution of
the process. The surface condition after milling on CNC woodworking machines must fulfil
very high criteria resulting from continually increasing customer requirements as well as
trends to shorten technological processes by eliminating troublesome technological
operations, e.g. sanding. From practical point of view, a surface after milling should not
require any other processing. High requirements regarding effective processing can only be
achieved by the application of precisely manufactured tools accurately chucked in modern
fixtures of working assemblies of woodworking machines. Accurate workmanship and
geometry of the tool cutting edge exert a very strong influence on the quality of the processed
surface, especially with regard to profile processing. Profile milling of solid wood
characterised by a number of factors associated, in particular, with anisotropic wood structure
is exceptionally challenging. Another important issue is connected with the wear of the
cutting edge and its impact on surface quality (Pinkowski et al. 2009, Pohl 2005, Szyma ski
et al. 2009). Variations in the setting of the cutting edge in relation to the processed material
in the course of curvilinear profile milling exerts a strong influence on the surface quality in
individual segments of the processed profile. Tool manufacturers continue to look for
solutions which would make it possible to assess the condition of the surface after processing
from the point of view of the cutting edge construction. The performed investigations should
shed some light on some problems from this area.
The objective of this research project was to determine milling quality of solid
oakwood profiled on a CNC woodworking machine from the point of view of selected factors
regarding the cutting edge and processed material.
METHODS
Oakwood (Querqus robur L.) samples 397 mm long, 56 mm wide and 22 mm thick
with oriented and repeatable arrangement of annual rings, were prepared and each of them
141
was subjected to profile milling on their circumference on a CNC woodworking machine.
Processing parameters are collated in Table 1.
Table 1. Processing parameters applied during milling on a CNC woodworking machine
Processing parameters
Value
Feed speed (vf)
3 m·min-1
Maximum machining diameter (Dmax)
85 mm
Minimum machining diameter (Dmin)
52 mm
rotational speed (n)
12000 min-1
Number of machining cutting edges (z)
2
Material of knifes
HM
The tool used in the described experiments consisted of a mandrel profile cutterhead
with a ProfilCut type of blade fixture. The processing was performed on a Weeke – Venture 3
processing centre using a tool chucked in an HSK milling fixture. The processed element was
mounted using grips which allowed processing of narrow elements. The tool as well as the
sample fixed on the processing centre is presented in Figure 1.
Fig. 1. Cutterhead and sample during milling.
Samples processed using a sharp and worn cutterheads were analysed. The maximum
wear of the tool was achieved when the milling distance covered by the blade during
processing of oakwood reached 400 running meters (rm). The adopted principal wear
(technological) criterion of the cutting edge was the observed processing quality.
Samples subjected to roughness assessment were characterised by moisture content of
8%. Selected surface roughness parameters were examined for two sets of samples of definite
arrangement of annual rings: tangential, semi-radial and radial. The first sample set was
processed using sharp blades, while the second set – using worn blades. Figure 2 shows the
view of samples prepared for investigations.
Measurements on each sample were performed in three characteristic places
designated with letters: G, D and W (Fig. 3).
Surface profiles were registered using a Carl Zeiss ME-10 profilometer equipped in a
measuring gauge with a rounding radius of 10 Pm and the apex angle of 90o. The feed
velocity in the course of recording of the profile was set at 100 Pm·s-1. Data collected during
recording were subjected to filtration in accordance with PN-EN ISO 13565-1:1999 and PNEN ISO 11562:1998 standards. The applied cut-off length was 0.8 mm. The following
parameters of wood surface roughness were adopted in accordance with the PN-84/D01005
standard: arithmetic average height Ra and the average peak to valley roughness Rz.
142
Annual ring distribution:
semi-radial
tangential
radial
A
B
Fig. 2. Samples prepared for experiments: A – samples after processing with a sharp blade; B - samples after
processing with a worn blade.
Fig. 3. Designation of measurement paths on examined samples
RESULTS
Values of the adopted roughness parameters are collated in Table 2, whereas Figures 4
and 5 present comparisons of surface roughness parameters of the examined samples
depending on the distribution of annual rings and the milling distance.
Table 2. List of the analysed surface roughness parameters
Annual ring
distribution
tangential
semi-radial
radial
Measurement
place
G
D
W
G
D
W
G
D
W
Roughness parameter
Ra [Pm]
Rz [Pm]
Machining distance [rm] Machining distance [rm]
1
400
1
400
0,95
1,25
5,33
6,75
1,06
1,46
5,7
8,15
0,42
0,72
2,31
3,97
0,99
2,02
5,44
11,31
0,77
1,53
4,22
8,5
0,66
0,85
4,05
4,71
1,1
1,42
6,32
7,69
0,74
1,14
4,31
6,01
0,72
1,03
4,38
5,76
143
a)
b)
c)
Fig. 4. Arithmetic average height Ra of the profile depending on the distribution of annual rings and the milling
distance of the tool for three measuring paths: a) D, b) G, c) W.
a)
b)
c)
Fig. 5. Average peak to valley roughness Rz of the profile unevenness depending on the distribution of annual
rings and the milling distance of the tool for three measuring paths: a) D, b) G, c) W.
The analysis of surface roughness parameters presented in Figs. 4 and 5 make it
possible to conclude that there was a clear increase in the values for the surface processed
with the worn cutting edge in comparison with the surface processed with the sharp blade. For
the Ra parameter, this increase ranged from 22% in the case of the radial system for the G
measuring path to 50% in the case of the semi-radial system for G and D measuring paths. In
the case of the Rz parameter, the increase ranged from 15% for the semi-radial system for the
W measuring path to over 50% for the semi-radial system for G and D measuring paths.
The comparison of roughness parameters from the point of view of annual ring
distribution as well as the choice of measuring paths failed to indicate unequivocally any
interrelations.
The maximal oakwood milling distance for all the analysed annual ring arrangements
amounting to 400 rm constituted the upper limit and, in some cases, exceeded it. It was the
distance at which it was possible to accept the results of processing from the point of view of
the occurrence of burns. Burns occurred both on straight sections as well as on corners. Figure
6 presents examples of burns.
The most conspicuous burns on straight sections were observed on samples with radial
annual ring arrangement and the least visible – for the tangential ring arrangement. Corners
changed colour as a result of burning irrespective of the distribution of annual rings.
144
tangential
Annual ring distribution
semi-radial
radial
A
B
Fig. 6. Effects of burns of the examined samples: A – straight sections; B – corners
CONCLUSION
Profiles of oakwood surfaces milled on a CNC woodworking machine using a
cutterhead with worn cutting edges showed a distinct increase of roughness parameters in
comparison with surfaces processed with sharp blades. The increase for the Ra parameter
ranged from 22% to 50% and for the Rz parameter – from 15% to 52%, depending on the
annual ring distribution and location of the measurement.
Significant spreads of increased roughness of oakwood surfaces as well as the location
of the determined wood burns indicate the necessity for the determination of a technologically
optimal criterion of the cutting edge wear with reference to places of processing characterised
by the most unfavourable processing results. Identification of such places, which requires
further investigations, can provide important information about the construction and geometry
of the cutting edge as well as about the selection of milling parameters.
REFERENCES
1. PINKOWSKI G., SZYMA SKI W., GILEWICZ A., KRAUSS A. (2009): Impact of
the wear of the cutting edge on selected parameters of the surface geometric structure
after wood milling. Ann. WULS-SGGW, Forestry and Wood Technol. 69: 187-191
2. PN-84/D-01005:
Chropowato
powierzchni
drewna
i
materia ów
drewnopochodnych. Terminologia i parametry.
3. PN-EN ISO 11562:1998: Specyfikacje geometrii wyrobów. Struktura geometryczna
powierzchni: metoda profilowa. Charakterystyki metrologiczne filtrów z korekcj
fazy.
4. PN-EN ISO 13565-1:1999: Specyfikacje geometrii wyrobów. Struktura geometryczna
powierzchni: metoda profilowa; powierzchnie o warstwowych w a ciwo ciach
funkcjonalnych. Filtrowanie i ogólne warunki pomiaru.
5. POHL P. 2005: Studia nad pomiarami struktury geometrycznej powierzchni drewna i
tworzyw drzewnych. Wydawnictwo Akademii Rolniczej im. Augusta Cieszkowskiego
w Poznaniu.
6. SZYMA SKI W., GILEWICZ A., PINKOWSKI G., BEER P. (2009): Durability of
blades covered by multilayer anti-wear coatings during wood milling. Annals WULS
– SGGW. Foresty and Wood Technology 69: 353 – 357
145
Streszczenie: JakoĞü frezowania profilowego na obrabiarce CNC. W pracy przedstawiono
badania dotycz ce jako ci obróbki elementów profilowych wykonanych na centrum
obróbkowym CNC. Badania przeprowadzono na elementach z drewna litego d bowego o
okre lonym uk adzie s ojów z wykorzystaniem g owicy frezowej z dwoma kompletami no y:
ostrych i zu ytych. W czasie bada zastosowano produkcyjne parametry obróbki. Jako
frezowania okre lano poprzez pomiar i analiz parametrów chropowato ci obrobionych
powierzchni, z wykorzystaniem profilografometru z odpowiednim oprzyrz dowaniem.
Stwierdzono zró nicowane zale no ci pomi dzy stanem ostrza, a chropowato ci obrobionej
powierzchni, w uj ciu uk adu s ojów drewna i miejsc lokalizacji pomiaru.
Grzegorz Pinkowski, Waldemar Szyma ski
60-627 Pozna , Poland,
38/42 Wojska Polskiego st.,
e-mail: WSzyma [email protected]
Impact of the cutting edge condition on the results of oak wood milling
GRZEGORZ PINKOWSKI, WALDEMAR SZYMA SKI ANDRZEJ KRAUSS
Abstract: Impact of the cutting edge condition on the results of oak wood milling. The study presents results of
investigations dealing with the effect of wear of cutting edges for profile milling on oak wood (Quercus robur
L.) surface roughness. The discussed experiments were carried out on a Weeke-Venture 3 processing centre
using a profile cutterhead with a blade fixture of the ProfilCut type of Leitz Company. Investigations included
analyses of the surface obtained as a result of processing after the execution of the milling distance
corresponding to: 1, 50, 100, 200, 300 and 400 running meters (rm). Values of the following two main surface
roughness parameters were determined: arithmetic average height Ra and the average peak to valley roughness
Rz. A significant increase of the analysed roughness parameters in the function of machining distance was
found.
Key words: cutting edge wear, surface geometric structure, wood milling, oak.
INTRODUCTION
Oakwood is widely applied in various sectors of wood industry. Due to its hardness
and durability, it provides good material for the manufacture of solid furniture of both
functional and representative value. Oakwood is also frequently used to manufacture small
ornamental elements of complex shapes. Wood structure, on the one hand, constitutes
material resistant to surface damage and, on the other, poses a number of problems connected
with its processing. The requirements are associated with the selection of appropriate tools of
specific geometry and cutting edge structure which will ensure proper durability and
processing quality.
Wood profile milling is usually realised using cutterheads with various methods of
chucking of cutting edges on numerically controlled woodworking machines. The way of
cutterhead fixing in working assemblies of CNC woodworking machines plays a significant
role and the quality of the finished surface is very important. The quality of the processed
surface is usually assessed on the basis of such roughness parameters as Ra and Rz (Aguilera
& Zamora 2009, Pinkowski et al. 2009, Pohl 2005).
Variability of the applied timber materials as well as their impact on treatment
processes make is necessary to conduct many investigations concerning the processing effects
of solid wood and wood-based materials examining various aspects of the process, e.g. in the
function of rotation velocity of the tool wear (Mitchell & Lemaster 2002, Szyma ski et al.
2009). The aim of these experiments was to ascertain the impact of the tool condition
undergoing wear during oakwood milling on the quality of the surface obtained following
profile milling.
METHODS
An oakwood multisample was prepared. Consecutive profile millings approximately
100 mm long one after another were carried out along side planes of the multisample.
Consecutive millings were performed using a tool after a specific production cycle of
oakwood profile processing. The processing cycle was determined by the realised distance of
machining by the given blade expressed in running meters. The multisample was milled along
147
the following distances: 1, 50, 100, 200, 300 and 400 running meters (rm) which allowed
standardisation of the experimental conditions with regard to their comparability.
The following processing parameters were employed during investigations:
x
feed speed
vf = 3 m·min-1
maximum machining diameter
Dmax = 85mm
x
x
minimum machining diameter
Dmin = 52mm
x
rotational speed
n = 12000min-1
number of machining cutting edges z = 2.
x
A Leitz Company profile, mandrel double-blade cutterhead with PrifilCut type of
blade fixing was used and the processing was conducted on a Weeke-Venture 3 processing
centre. The cutterhead was fixed in a chuck of the machine working assembly using an HSK
cone. The milling elements and the multisample during processing were fixed using chucks
which allowed processing of narrow elements. The tool as well as the numerical centre used
in experiments is presented in Figure 1.
Fig. 1. Cutterhead and CNC woodworking machine employed in experiments
The performed analyses involved the multisample processed using a tool with new
blades and with the same but worn blades along the following machining (oakwood profile
milling) distances: 1, 50, 100, 200, 300 and 400 rm.
Moisture content of the experimental sample was 8%. Selected surface roughness
parameters for two measurement places of each segment of the milled profile were examined:
one surface was situated paralelly to the tool rotation axis (B) and the other – perpendicularly
to the tool rotation axis (A). Designations of places of measurements are shown in Figure 2.
148
Axis of rotation of tool
A
B
Fig. 2. Designations of places of measurements
Surface profiles were recorded using a Carl Zeiss ME-10 profilomerter equipped in a
measuring gauge with a rounding radius of 10 Pm and the apex angle of 90o. The feed
velocity in the course of recording of the profile was set at 100 Pm·s-1. Data collected during
recording were subjected to filtration in accordance with PN-EN ISO 13565-1:1999 and PNEN ISO 11562:1998 standards. The applied cut-off length was 0.8 mm. The following
parameters of wood surface roughness were adopted in accordance with the PN-84/D01005
standard: arithmetic average height Ra and the average peak to valley roughness Rz.
RESULTS
Calculated values of roughness parameters are shown in Table 1. Figures 3 and 4
present comparisons of surface roughness parameters of the examined samples depending on
the milling distance.
Table 1. List values of the analysed surface roughness parameters
Parameter Ra [Pm]
Milling distance [m] measurement place
1
50
100
200
300
400
A
0,93
1,29
1,12
1,66
1,84
1,59
B
0,76
0,98
1,12
1,54
1,7
1,59
Parameter Rz [Pm]
measurement place
A
5,24
5,7
7,09
10,04
8,47
8,28
B
4,32
5,67
7,01
8,04
9,08
8,34
The dependence of the arithmetic average height of the Ra profile on the machining
distance showed an increasing tendency. This trend was noticeable for both measurement
places and ranged from 0.76 Pm – for the initial value of the machining distance for place B
to 1.84 Pm for the machining distance of 300 rm, for place A. Slightly higher values of the Ra
parameter for the A measurement place than for place B can be noticed in Figure 3.
149
Fig. 3. Arithmetic average height Ra of the profile depending on the machining distance for the analyzed
measurement places
A similar tendency was observed in the case of the unevenness height of profile Rz.
Also here, a distinct growing trend is visible. The smallest values of this parameter (Fig. 4)
were found for the surface obtained after the machining distance of 1 rm, while the highest
values for the surface obtained after the machining distance of 300 rm. Analysing the
obtained research results, it can be stated that the surface obtained after the machining
distance of 400 rm was characterised by smaller values of both parameters.
Fig. 4. Average peak to valley roughness Rz of the profile depending on the machining distance of the tool for
the analysed measurement places.
150
In the final phase of the analysed machining distance, i.e. 400 rm, burns were found to
occur which probably contributed to surface smoothing which may explain the lower values
of both analysed roughness parameters.
CONCLUSION
The results of the performed investigations showed that, together with the increase of
the machining distance, values of roughness parameters Ra and Rz were also found to
increase. However, both values declined in the case of the longest analysed machining
distance. The most probable cause of this situation could have been the phenomena which
contributed to burning of the examined surfaces.
Slight difference occurred in the obtained values of the surface roughness parameters
for the two measurement places determined on surfaces perpendicular to each other. Higher
values of roughness parameters were recorded for the surface oriented perpendicularly to the
rotation axis which could be attributed to the unfavourable configuration of this surface from
the point of view of the construction of the tool cutting edge.
REFERENCES
1. AGUILERA A., ZAMORA R. (2009): Surface roughness in sapwood and heartwood
of Blackwood (Accacia melanoxylon R. Br.) machined n 90-0 direction. Eur. J. Wood
Prod.67:297-301
2. PINKOWSKI G., SZYMA SKI W., GILEWICZ A., KRAUSS A. (2009): Impact of
the wear of the cutting edge on selected parameters of the surface geometric structure
after wood milling. Ann. WULS-SGGW, Forestry and Wood Technol. 69: 187-191
3. MITCHELL P, LEMASTER R. (2002) Investigation of machining parameters on the
surface quality in routing soft maple. For Prod J 52(6):85–90
4. PN-84/D-01005:
Chropowato
powierzchni
drewna
i
materia ów
drewnopochodnych. Terminologia i parametry.
5. PN-EN ISO 11562:1998: Specyfikacje geometrii wyrobów. Struktura geometryczna
powierzchni: metoda profilowa. Charakterystyki metrologiczne filtrów z korekcj
fazy.
6. PN-EN ISO 13565-1:1999: Specyfikacje geometrii wyrobów. Struktura geometryczna
powierzchni: metoda profilowa; powierzchnie o warstwowych w a ciwo ciach
funkcjonalnych. Filtrowanie i ogólne warunki pomiaru.
7. POHL P. 2005: Studia nad pomiarami struktury geometrycznej powierzchni drewna i
tworzyw drzewnych. Wydawnictwo Akademii Rolniczej im. Augusta Cieszkowskiego
w Poznaniu.
8. SZYMA SKI W., GILEWICZ A., PINKOWSKI G., BEER P. (2009): Durability of
blades covered by multilayer anti-wear coatings during wood milling. Annals WULS
– SGGW. Foresty and Wood Technology 69: 353 – 357
151
Streszczenie: Wpáyw stanu ostrza na efekty frezowania drewna dĊbowego. W pracy
zaprezentowano wyniki bada wp ywu zu ycia ostrzy no y do frezowania profilowego na
chropowato powierzchni drewna d bowego (Quercus robur L.). Badania wykonano na
centrum obróbkowym Weeke-Venture 3 z zastosowaniem g owicy frezowej profilowej z
mocowaniem no y typu ProfilCut firmy Leitz. Analizowano powierzchni uzyskan w
wyniku obróbki po zrealizowanej drodze skrawania równej 1, 50, 100, 200, 300 i 400mb.
Wyznaczono warto ci dwóch podstawowych parametrów chropowato ci powierzchni tj.
redniego arytmetycznego odchylenia profilu Ra oraz wysoko ci nierówno ci profilu Rz.
Stwierdzono istotny wzrost analizowanych parametrów chropowato ci w funkcji drogi
skrawania.
Grzegorz Pinkowski, Waldemar Szyma ski, Andrzej Krauss
e-mail: WSzyma [email protected]
Annals of Warsaw University of Life Sciences-SGGW
(Ann. WULS-SGGW, For. And Wood Technol. 72, 2010)
Investigations on the execution accuracy of floor boards
GRZEGORZ PINKOWSKI, WIES AW ZAKRZEWSKI, MAGDALENA JOKIEJ,
ANDRZEJ KRAUSS
Abstract: Investigations on the execution accuracy of floor boards. Experiments were carried out with the aim
to determine execution accuracy of width and thickness dimensions of floor boards in industrial conditions. The
obtained research results were evaluated with the assistance of the STATISTICA computer software in which
process quality capability indices were calculated and Shewhart
_
x s
control charts were prepared.
Keywords: floor boards, quality capability, control charts
INTRODUCTION
Floor boards constitute one of the elements of the architectural internal equipment and
are considered to be one of the types of flooring which have been an important element of
building engineering for many centuries.
One of the more important elements of processing accuracy is dimensional exactness.
It is impossible to manufacture a series of elements of ideal exactitude. The shape, dimension
and surface geometrical structure of a processed element should correspond to the element
specified on the working drawing (Zakrzewski et al. 2004).
Dimensional accuracy is one of the major factors affecting the quality evaluation of a
given object. In order for the dimension of a manufactured element to be considered as
acceptable, its value must be contained within a tolerance interval. Assuming that the
tolerance interval is a variability proceeding in accordance with normal distribution enforced
by standards, the centre of tolerance, which need not always be consistent with the nominal
dimension, should be considered as the mean dimension. This consistence occurs only in the
case of symmetrical tolerance (Zakrzewski & Staniszewska 2002). The main parameters of
the normal distribution include: arithmetic mean and average deviation. As a result of action
of various systematic and random factors affecting these processes, they undergo changes
which affect the level of quality. The basis of the quality control execution is maintenance
during the production process of the variability of these parameters within boundaries which
will guarantee the assumed level of quality with a satisfactory margin of probability (Marek et
al. 1997).
At the present time, automatic quality control in wood industry frequently cannot be
ensured due to lack of modern woodworking machines characterised by high accuracy
(Lisi an et al. 2001). In such situation, it is only possible to control the process which makes
it possible only to conclude if and at what level acceptable dimensional variability and
stability are fulfilled. For a production engineer, what is important is the knowledge of how to
maintain dimensional accuracy by woodworking machines employed in the process in
accordance with the requirements established for products. The method of control of the
maintenance of the dimensional accuracy is appropriate also to examine other quality traits.
Therefore, in the literature on the subject (Czy ewski 1993, PN-ISO3534-2), a general term
“process quality capability” has been accepted. However, apart from the process quality
capability, its stability is equally important which means that it guarantees concentration of its
values symmetrically in relation to the centre of the field of tolerance and, in such a way, that
153
the variability interval of the controlled dimension value does not exceed boundaries of the
acceptable variability determined for it. The main objective of the application of Shewhart
control charts is the achievement of such process condition (Matuszewski & Šatanowá 1997,
Iwasiewicz 1999).
This study focuses on the problem of the statistical execution accuracy of floor boards
manufactured in the Witar Tartak Tyble Ltd. When assembling floors, it is particularly
important to ensure appropriate width and thickness dimensions of elements. According to
PN-EN 13990, the tolerance of these dimensions amounts to: T=3 mm for width and T=2 mm
for thickness.
The objective of this study was to examine the width and thickness execution accuracy
of floor boards conducted in industrial conditions. It comprised determination of quality
capability and process alignment as well as evaluation of the dimensional stability of
_
manufactured elements using for this purpose x s control charts.
METHODOLOGICAL ASSUMPTIONS
The experimental material comprised floor boards of 28 mm * 110 mm cross section
manufactured from solid pine wood (Pinus sylvestris L.) planed on four sides with sides
profiled into tongue and key.
The top side of floor boards was planed twice and there were two relief grooves in the
bottom side to prevent warping. Board top and bottom surfaces were formed and tongues and
keys were made with the assistance of a four-side planer, type Unimat CLASSIC of Weinig
Company. Figure 1 shows the spindle arrangement of the employed planing machine.
Fig. 1. Spindle arrangement of the applied type Unimat CLASSIC planing machine; 1, 6 – heads forming the top
side of boards, 2, 3 – tongue and key profile milling cutters; 4 - disc cutter for relief grooves, 5 – head forming
the bottom side
The diagram showing the formation of sides and relief grooves of the floor board is
presented in Fig. 2.
Fig. 2. Block diagram illustrating formation of sides and relief grooves of the floor board
a – double cutters, b – disc cutters
154
The moisture content of the board surface layer was measured with the assistance of a
WIP-20D hygrometer whose principle is based on measurements of the dielectric constant.
The instrument makes it possible to take measurements with r0.1% accuracy in accordance
with EN 13183-2. The width and thickness of boards was measured using a calliper with a
digital display and r0.01 mm accuracy.
Width and thickness measurements were conducted after floor boards were totally
completed during five consecutive days and on each day, they lasted for 8 hours, i.e. a
complete work-shift. Every day, the total of 25 samples was subjected to investigations. Each
sample consisted of five elements and the samples were examined at identical time intervals,
approximately every 20 minutes with 3 measurements of width and 3 measurements of
thickness performed on each element. Therefore, on each measurement day, the total of 125
elements was examined obtaining 750 measurements, including 375 thickness and 375 width
measurements. The width of elements was measured on their top plane because the width of
the bottom plane (under the key) was by 1 mm smaller. Two measurements were taken at the
distance of 200 mm from heads of the examined elements and the third measurement – in the
middle of its length. Measurements of the board thickness were taken at the same distance
from the heads as in the case of width.
_
A stabilisation method (Czy ewski 1992) was chosen to prepare x s control charts
which were designated on diagrams with X-S letters. Diagrams illustrating the quality
capability and position of the process as well as control charts were all computer made using
for this purpose the STATISTICA 8PL software. The quality capability and process
alignment were assessed by values of cp, cpk and ME indices (Zakrzewski and Staniszewska
2002). Description of control charts as well as the method of calculation of their parameters
can be found in an article illustrating element execution accuracy of ‘duoparquet’
(Zakrzewski et al. 2009).
RESEARCH RESULTS AND THEIR ANALYSIS
Table 1 collates index values of the process quality capability cp and alignment cpk.
The Table also includes parameter ME which constitutes the accuracy of the dimensional
setting of the woodworking machine.
Table 1. Index values of the process quality capability cp and alignment cpk and dimensional setting of the
woodworking machine ME (in mm).
Thick
ness
Width
Day 1
Day 2
Day 3
Day 4
Day 5
1.82
1.51
2.63
4.61
2.69
cp
1.67
1.42
2.52
4.07
2.49
cpk
0.12
-0.10
-0.06
-0.18
0.12
ME
7.95
5.10
2.28
4.83
6.81
cp
7.59
4.73
2.03
4.34
6.22
cpk
0.05
0.07
-0.11
0.10
0.09
ME
It is evident from data presented in Table 1 that the execution quality capability of
board width and thickness dimensions on each measurement day was satisfactory as the
dimension scatter was, in the best case, smaller than the tolerance for the width by 4.61 times
(day 4) and for the thickness by 7.95 times (day 1) and, in the worst case, by 1.51 times for
the width (day 2) and by 2.28 times for the thickness (day 3).
In all cases, the alignment index cpk differed slightly from the cp value and its smallest
value amounting to 1.42 (day 2) was determined for board thickness. However, even this
worst value exceeded significantly unity below which, as is well known, production defects
would occur.
155
The setting accuracy of the woodworking machine ME ranged from -0.06 mm for the
width (day 3) to 0.18 mm for the width (day 4). This negligible ME value exerted a significant
impact on small differences between cp and cpk indices and, at a slight dimensional scatter,
guaranteed defect-free production.
Process stability was illustrated by control charts presented in Figs. 3 to 6. Due to
space limitations of the article, only four control charts are included illustrating the best and
the worst cases of process stability.
Figures 3 and 4 present control charts of the thickness dimension for the best and
worst process stability.
Fig. 3. Control chart for thickness dimension on day 5 of measurements
Fig. 4. Control chart for thickness dimension on day 1 of measurements
156
The process was most stable on the fifth day of measurements (Fig. 3) and its stability
was the worst on the first day of measurements (Fig. 4). The central line X- r and S- r as well
as control lines GLK and DLK are marked as continuous lines, while warning lines GLO and
DLO – as dashed lines. The arithmetic mean from individual samples x r and sj are marked as
squares or when a signal occurred – as circles. In Figure 3, for the path of the arithmetical
mean X from individual samples x r, the difference between the position of the top control
line GLK and bottom control line DLK amounted to 0.119 mm (27.973 – 27.854), while for
the path of mean deviation S: GLK – DLK = 0.087 mm. On path X warning lines were found
exceeded for four samples: 3, 6, 18 and 20. No signals were found, however, from single
samples that would indicate destabilisation of the process. On path S, phenomena of “trend”
type can be observed for samples 9-16 and of “run” type for samples 10-16. On the other
hand, in Figure 4 the range of stability on path X: GLK – DLK = 28.087 – 28.004 = 0.083
mm, while the difference of values of control lines on path S amounted to GLK – DLK =
0.060 mm. Disturbances occurred in Figure 4 indicating destabilisation of the process.
Samples 3 and 8 gave a signal on path X, whereas sample 2 – both on paths and X and S.
Samples 9 and 11 on path X exceeded the bottom warning line, while on path S, top warning
line was observed to be exceeded for sample 5.
Figures 5 and 6 show control charts prepared for the width dimension for the best and
worst stabilised processes.
Fig. 5. Control chart for width dimension on day 4 of measurements
The process was found to be most stable on day 4 of measurements (Fig. 5) and its
stability was worst on day 2 (Fig. 6). In Figure 5, for the path of the arithmetic mean X from
individual samples x r, the difference between the position of the top GLK and bottom DLK
control lines amounted to 109.967 – 109.692 = 0.275 mm, while for the path of standard
deviation S, GLK – DLK = 0.198 mm. On the other hand, in Figure 6, the range of stability
on path X: GLK – DLK = 110.190 – 109.622 = 0.568 mm, whereas the value difference of
control lines on path S amounted to: GLK – DLK= 0.414 mm. On day 4 of measurements, no
signal of transgression of the control line occurred from individual samples and in three cases,
on path X, warning lines were trespassed, namely for samples 13, 16 and 21. On the other
hand, on path S, such transgressions took place for samples 5, 9 and 25.
157
Fig. 6. Control chart for width dimension on day 2 of measurements
On the second day of measurements, up to thirteen signals from individual samples
occurred, of which eleven signals were observed on path X and two on path S. In addition, a
“run” took place on path X for samples 6-15 below the X- r axis and on both paths, a
phenomenon of “middle one third” occurred (a collective publication 1999) indicating too
large value scatter from individual samples. The likely cause was a too large difference in the
width dimension before processing in individual samples on this measurement day.
CONCLUSIONS
1. On the basis of observations of the process capability cp and alignment cpk indices, the
process was assessed as quality capable.
2. A partial instability of thickness and width dimension maintenance in the course of the
process occurred caused by signals of transgression of lines controlling values by
some samples. In addition, phenomena of ‘trend’, ‘run’ and ‘middle one third’ type
developed on some control charts.
3. The performed investigations revealed that the degree of the tool point dulling during
the five-day interval failed to influence the obtained research results.
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9. NORMA PN-ISO 3534-2(1994): Statystyczne sterowanie jako ci . Terminologia i
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10. ZAKRZEWSKI W., STANISZEWSKA A. (2002): Dok adno obróbki ci ciem.
Wydawnictwo im. Augusta Cieszkowskiego w Poznaniu.
11. ZAKRZEWSKI W., PINKOWSKI G., KRAUSS A., DRYJA SKI T. (2004): On the
machining exactness of the “DUO-PARQUET” elements. Folia Forestalia Polonica, B
(35):85-98.
12. ZAKRZEWSKI W., PINKOWSKI G., KRAUSS A., RENTZ A. (2009):
Investigations on the execution accuracy of solid parquet elements. Acta Scientiarum
Polonorum. Le nictwo
i Drzewnictwo 8(4):75-89.
Streszczenie: Badanie dokáadnoĞci wykonania desek podáogowych. Przedmiotem bada by a
kontrola dok adno ci wykonania wymiarów grubo ci i szeroko ci elementów desek
pod ogowych przeprowadzona w warunkach przemys owych. Wyniki bada opracowano z
u yciem programu komputerowego STATISTICA 8PL s u cego mi dzy innymi do
obliczania wska ników zdolno ci jako ciowej cp i cpk oraz do tworzenia kart kontrolnych
Shewharta. Badanie zdolno ci jako ciowej oraz stabilno ci utrzymania wymiarów w procesie
produkcyjnym prowadzono w okresie pi ciu tygodni kartami kontrolnymi w odniesieniu do
wymaga normy PN-EN 13990:2005. Na podstawie obserwacji warto ci wska ników cp i cpk
proces oceniono jako zdolny jako ciowo, za na podstawie analizy kart kontrolnych
cz ciowo niestabilny.
Grzegorz Pinkowski
60-627 Pozna ,
Poland
Feed rate influence on feed force and cutting torque while drilling in MDF
(Middle Density Fibreboard)
PIOTR PODZIEWSKI, JAROS AW GÓRSKI
Wood Mechanical Processing Department, Warsaw University of Life Sciences– SGGW
Abstract: Feed rate influence on feed force and torque while drilling in MDF (Middle Density Fibreboard). The
article describes influence of the feed rate on cutting resistance while drilling the raw MDF. A standard CNC
Busellato Jet 130 machine was used for the test, with mounted single blade LEITZ 10 mm diameter drill. During
examinations a piezoelectric KISTLER sensor fastened in the measuring platform was used to capture a signal of
feed force and the cutting torque moment. Cutting resistances for five values of feed per revolution (0.1; 0.15;
0.2; 0.25 and of 0.3 mm) and three variants of the spindle speed (3000, 6000, 9000 rpm) were examined. For
above parameters appropriate values of the feed rate [m/min] were calculated. Test results allowed formulating
the conclusion that the feed rate has an influence on axial force and twisting moment while drilling the MDF.
Keywords: cutting resistance, MDF, feed force, cutting torque
INTRODUCTION
Drilling of wood-based materials, especially MDF is common technological process in
wood industry. Influence of cutting parameters such as feed rate (or feed per revolution) on
cutting resistance is well known problem [Staniszewska, Zakrzewski 2002; Orlicz 1988].
Knowledge of cutting resistance accompanying the process of drilling and its sensitivity to
feed rate can be used to analysis of production efficiency and mac. Drill bits are working in
difficult conditions (not effective cooling), cutting forces can deform the tool and for this
reason the feed rate cannot be too high.
That is why the problem of feed rate influence on feed force and cutting torque while
drilling in MDF was examined in this paper.
Machining was realized by means of standard CNC machine BUSELLATO JET 130.
Drilling was realized using brand new single bladed LEITZ drill (fig.1) with diamond
polycrystalline cutting edge (ID NR:091193) .The holes were drilled in raw MDF using
mentioned above tool.
Simultaneously during drilling took place registration of feed force and cutting torque
by using measuring platform with mounted piezoelectric sensor (Kistler 9345A) as a part of
this device (fig.2). Platform is modified version of the one used by Czarniak and Górski
[2009].
Five variants of feed per revolution were assumed: 0,1 mm; 0,15 mm; 0,2 mm; 0,25
mm; 0,3 mm. Also three variants of spindle speed: 3000 rpm, 6000 rpm and 9000 rpm were
assumed (for above parameters appropriate values of the feed rate [m/min] were calculated
and used). However test showed no significant influence of cutting speed on registered signals
so results were averaged (arithmetic mean). Each set of parameters was tested 20 times, that
resulted in 300 recordings.
160
Fig. 1. Mounted LEITZ drill
Fig. 2. Measuring platform with piezoelectric sensor and clamped sample
Test showed that feed per revolution ( ) has a linear influence on both feed force (Fz
[N]) and cutting torque (M [Nm]). Doubling the feed per revolution from 0,1 mm to 0,2 mm
causes increase of axial force for approximately 15 N, it raises the same amount when feed
per revolution is set to 0,3 mm (fig.3a). Similarly reacts value of cutting torque, growing from
0,15 Nm for feed of 0,1 mm through 0,19 Nm for 0,2 mm to 0,23 Nm for 0,3 mm.
161
a.
b.
Fig. 3. (a) Influence of feed per revolution on feed force; (b) Influence of feed per revolution
on cutting torque
CONCLUSION
Obtained results allow to formulate following conclusion: feed per revolution had a
significant, linear influence on both feed force and cutting torque.
REFERENCES
1. CZARNIAK P., GÓRSKI J., 2009: Cutting resistance during drilling. Annals of
Warsaw University of Life Sciences – SGGW, No 67
2. STANISZEWSKA A., ZAKRZEWSKI W., 2002: Obróbka ci ciem. Wyd. AR w
Poznaniu
3. ORLICZ T., 1998: Obróbka drewna narz dziami tn cymi. Wyd. SGGW – AR w
Poznaniu
162
Streszczenie: Wpáyw prĊdkoĞci posuwu na siáĊ posuwową i moment obrotowy skrawania
podczas wiercenia w páycie MDF. W artykule opisano wp yw pr dko ci posuwu na opory
skrawania podczas wiercenia surowej p yty MDF. Do bada wykorzystano standardow
obrabiark CNC Busellato Jet 130. Wiercono przy u yciu wiert a jednoostrzowego marki
LEITZ o rednicy 10mm. Podczas bada wykorzystano czujnik piezoelektryczny KISTLER
zamocowany w platformie pomiarowej przy pomocy, którego, rejestrowany by sygna si y
osiowej oraz momentu skr caj cego. Badano opory skrawania dla pi ciu warto ci posuwu na
obrót (0,1; 0,15; 0,2; 0,25 oraz 0,3 mm) a tak e dla trzech wariantów pr dko ci obrotowej
wrzeciona (3000, 6000, 9000 obr/min). Dla powy szych parametrów dobierane by y
odpowiednie warto ci pr dko ci posuwu. Wyniki bada pozwoli y na sformu owanie
wniosku, e pr dko posuwu wywiera wprost proporcjonalny wp yw na si posuwu i
moment obrotowy skrawania podczas wiercenia p yty MDF.
Piotr Podziewski, Jaros aw Górski
Faculty of Wood Technology SGGW,
Wood Mechanical Processing Department,
ul. Nowoursynowska 159,
02-776 Warsaw,
Poland
Studies on heat-transfer coefficient
of wood floor materials used in floor heating
P. POHL
Department of Woodworking Machinery and Basic of Machine Construction, Poznan University of Life
Sciences, 28, Wojska Polskiego Str, 60-637 Pozna , Poland
Abstract: Studies on heat-transfer coefficient of wood floor materials used in floor heating. The aim of
investigations was to examine heat-transfer coefficients of “Marchewka board”, floor boards of 20 mm thickness
intended to be used in floor heating systems. In order to increase their heat conductivity, thermal bridges were
made in the form of non-passage holes of 20 mm diameter which were filled with: concrete, aluminium discs and
a mixture consisting of 95% aluminium filings glued with adhesive. Results of these experiments were compared
with the results of investigations of the heat-transfer coefficient in floor boards without holes, with empty holes
and floor boards of other manufacturers. The best results were recorded for boards with holes filled with
aluminium filings. The heat-transfer coefficient in these boards was by 24% higher in comparison with boards
without holes.
Keywords: floor heating, floor boards, heat transfer.
INTRODUCTION
Wood materials intended for floor covering should simultaneously act as thermal
insulators preventing heat transfer to the floor/ceiling and, therefore, they should be
characterised by the lowest possible value of the heat-transfer coefficient k. On the other
hand, however, when floor heating is to be used, they should be characterised by the highest
value of this coefficient to allow heat transfer from the heating medium, usually mounted in
the concrete floor, to the heated room. However, wood as well as wood-based materials are
characterised by good heat insulating power and, hence, possess low value of the heat-transfer
coefficient [8, 9]. This coefficient can be increased by the application of thermal bridges
placed in holes of a foundation board (consisting of, for example, plywood 15 mm thick).
Such bridges should be made from materials of high thermal conductivity. This solution is
pending two patents: P-390587 “Layer board and ways of its production” [6] and P-391359
“Method of manufacturing of layer boards” [7].
RESEARCH OBJECTIVE
The aim of investigations was to determine heat-transfer coefficients for some material
variants of thermal bridges placed in holes of a foundation plate and to compare the obtained
results with heat-transfer coefficients for plates without thermal bridges and with boards of
manufacturers offering their products for floor heating.
RESEARCH METHODOLOGY
Heat-transfer coefficients k were determined by measuring the intensity of the heat
stream q using, for this purpose, sensors of heat stream intensity of MGS-3 type in the form of
discs of 50 mm diameter and 4.3 mm thickness. Inside each disc, there are approximately 650
copper-constantan thermo-elements connected serially. Thermojunctions are placed in the
vicinity of their flat surfaces. During measurements of heat stream intensity, the sensor is
placed on the examined sample floor with the assistance of a coupling agent, namely machine
cup-grease.
164
Thermoelectric voltage UT, which develops at the terminals of the sensor when
temperature difference occurs on its flat surfaces after placing it in streams of flowing heat,
was measured with the assistance of a digital voltage meter of V 530 type. The voltage meter
was set at the 100mV range and the accuracy of its readings amounted to ±0.01 mV. The
above-described methodology was employed in many earlier studies regarding determination
of the heat-transfer coefficient [1, 2, 3, 4, 5].
Figure 1 presents a block diagram of the experimental stand. It consists of a heat chamber
in which an electric bulb of 60W power was employed as a source of heat. Constant
temperature of 40oC was maintained in the chamber with the assistance of a contact
thermometer which switched the source of heat on and off by means of a relay switch. In
order to secure a uniform temperature distribution on the internal sample surface, a screen
made of 3 mm thick aluminum sheet was applied. The examined sample of the floor material
with the heat stream sensor fixed to it constitutes the top wall of the chamber. The sensor is
connected to the digital voltage meter. In order to guarantee constant conditions of heat
transfer between the sample with the heat sensor and the surroundings, a ‘cold chamber’ was
applied. Temperature measurements of the thermal chamber (under the sample) and cold
chamber (above the sample) were taken using laboratory mercury thermometers.
Figure 1. Block diagram of the experimental stand for investigations on heat-transfer coefficient of floor
materials from wood.
The intensity of the heat stream q is proportional to the thermoelectric voltage UT and
amounts to:
q
CU T [W / m 2 ]
where: C – sensor calibration constant. For the applied sensor C = 24.7 Wm-2mV-1.
The heat-transfer coefficient was calculated from the following formula:
k
q
T1 T2
>
CU T
W /(m 2 K )
T1 T2
@
where: T1 – temperature in the hot chamber,
T2 – temperature in the cold chamber.
Ten replications of measurements of each sample (once the conditions of heat transfer
became constant) were carried out each time changing the position of the sensor of the heat
stream on the surface of samples and then mean values, standard deviations and coefficients
of variability were calculated.
The following seven different floor samples were investigated: 5 floor samples
manufactured by Marchewka Company according to submitted patents, 1 floor board
165
manufactured by Barlinek Company and 1 floor board manufactured from a HDF board of 15
mm thickness:
1. Floor board 20 mm thick of 5 mm noble wood and 15 mm thick plywood foundation,
2. Floor board as in point 1 with 20 mm holes drilled at 19 mm spacings (Fig. 2),
3. Floor board as in point 2 with holes into which aluminium discs were pressed,
4. Floor board as in point 2 with holes filled with concrete,
5. Floor board as in point 2 with holes filled with aluminium material consisting of 95%
aluminium filings and adhesive – 2-component polyester material,
6. “Barlinek” floor board 15 mm thick made of 3 mm thick top noble wood and 12 mm
thick foundation of conifer wood,
7. HDF board panels 7 mm thick.
RESEARCH RESULTS
Results of investigations of the heat-transfer coefficient are presented in Table 1 and in
Figure 3.
The best results – the highest value of the heat-transfer coefficient k – among the
examined wood floor boards were obtained for the board with drilled holes filled with
aluminium mixture. The recorded heat-transfer coefficient k was by about 24% higher than
for the board without holes. Quite good results were also obtained in the case of boards with
holes filled with concrete (k coefficient by almost 22% higher), although this board is heavy
and difficult in handling (cutting, shortening).
Figure 2. Floor board 20 mm thick consisting of 15 mm plywood and noble wood 5 mm thick with 20 mm
holes drilled at 29 mm spacings (according to point 2 of the above list).
Table 1.
Results of investigations of the heat-transfer coefficient for different kinds of floor materials.
Standard
Coefficient of Increase
Heat-transfer
[%]
deviation
variability
No.
Kind of floor board
coefficient K
[W/m2K]
[%]
[W/m2K]
1
„MARCHEWKA board”
2.61
0.13
4.97
0
20 mm thick, no holes
2
2.84
0.17
6.03
8.8
20 mm thick, with holes
2.83
0.19
6.68
8.4
3
20 mm thick, with
aluminium discs
166
4
5
6
7
20 mm thick,
with concrete
20 mm thick,
with aluminium material
BARLINEK board
15 mm thick
7 mm HDF panel
3.21
0.10
3.07
21.6
3.24
0.11
3.28
24.1
2.86
0.09
3.27
9.6
4.13
0.11
2.77
58.2
The boards with holes filled with aluminium discs turned out to have unexpectedly low
heat-transfer coefficient k value which was, practically speaking, equal to the value of k in
boards with holes without filling.
4,5
4,13
Heat - transfer coefficient k [W/m2 K]
4
3,28
3,5
3
2,84
2,83
with holes
with
aluminium
discs
3,21
2,86
2,61
2,5
2
1,5
1
0,5
0
without
holes
" M A R C H E W K A
with
concrete
with
aluminium
material
Barlinek
board
7 mm HDF
panel
B O A R D "
Figure 3. Results of investigations of the heat-transfer coefficient for different kinds of floor materials.
In order to explain this phenomenon, the board was cut with a circular saw along the axis
of holes. It turned out that many of the aluminium discs were too short and an air cushion
developed between the discs and the bottom of holes which prevented a free air flow (Fig. 4).
The fact that not all discs were too short is confirmed by the highest value of the coefficient of
variability for this treatment (6.68%) and by Figure 4.
167
Air gaps
Figure 4. Cross section of board with holes filled with aluminium discs. Air gaps for 3 left discs isolate
effectively, right disc is proper.
CONCLUSIONS
1. As expected, the highest heat-transfer coefficient values were determined for the 7 mm
HDF board.
2. The highest heat-transfer coefficient values among floor products offered by the
Marchewka Company were recorded for boards with holes filled with aluminium
mixture and this solution is recommended for application.
3. The use of aluminium discs in drilled holes requires high precision of depth
measurements of holes and height of discs. It seems necessary to apply some kind of
‘contact agent’ to be used during their placement at the bottom of holes.
4. The application of concrete is also satisfactory (comparable with the use of aluminium
mixture) but such boards are heavier and difficult in handling.
5. Barlinek floor boards intended for floor heating showed heat-transfer coefficient
values comparable with those of the Marchewka Company boards with drilled holes
but without any heat transferring materials.
6. It is worth considering the application of a thick layer of aluminium foil placed
between the plywood and the top layer of noble wood and through-holes made in
plywood filled with aluminium mixture.
REFERENCES
1. P. POHL, M. HOFFMAN: Thermo-insulation properties od selected constructions of
beehive walls. International Apicultural Scientific Conference in centenary of Jan
Dzier on’s death. Pu awy 2006, p. 104-107.
2. P. POHL, T. ROGOZI SKI: Influence of wall construction on thermal-insulating of
wielkopolski beehive. Pszczelnicze Zeszyty Naukowe, Instytut Sadownictwa i
Kwieciarstwa, Oddzia Pszczelnictwa, Pszczelnicze Towarzystwo Naukowe, Pu awy
rok XLIII, nr 1, 1999, p. 71 – 77 .
3. P. POHL, T. ROGOZI SKI: Inpact of dampness of the insulation layer on wall heat
– insulating properties of walls of Wielkopolski beehives. In „Trieskowe a
beztrieskowe obrabanie dreva”. Stary Smokovec (Slovakia), Technicka univerzita vo
Zvolene, 2002, p. 329 – 332 .
4. P. POHL, T. ROGOZI SKI: Investigations on thermal insulation layer of beehives
manufactured form wood and wood – derived materials. In „Trieskowe a
beztrieskowe obrabanie dreva”. Stary Smokovec (Slovakia), Technicka univerzita vo
Zvolene, 2002, p. 323 – 328 .
168
5. P. POHL, T. ROGOZI SKI: Wp yw zawilgocenia warstwy izolacyjnej na
w a ciwo ci termoizolacyjne cian uli. Prace XXXVIII Naukowej Konferencji
Pszczelarskiej, Pu awy 2001, p.75-76.
6. Patent Application P-390587 „Deska warstwowa i sposób jej wytwarzania”
(26.02.2010).
7. Patent Application P-391359 „Sposób wytwarzania deski warstwowej” (19.05.2010).
8. www.lakiery.pl/parkiet_na_ogrzewaniu_podlogowym,p,38.html (25.08.2010).
9. www.budnet.pl/Izolacyjne_wlasciwosci_podlog_drewnianych,technologie_
budowlane,a=1180.html (25.08.2010).
Streszczenie: Badania wspóáczynnika przenikania ciepáa materiaáów podáogowych z drewna
stosowanych przy ogrzewaniu podáogowym. W pracy badano wspó czynniki przewodzenia
ciep a desek pod ogowych „Deska Marchewka” o grubo ci 20 mm, przeznaczonych do
stosowania przy ogrzewaniu pod ogowym. W celu zwi kszenia przewodzenia ciep a w
deskach tych wykonano mostki termiczne w postaci nieprzelotowych otworów o rednicy 20
mm, które wype niono betonem, kr kami aluminiowymi i mas z o on z 95% opi ków
aluminiowych po czonych lepiszczem. Wyniki tych bada porównano z wynikami bada
wspó czynnika przewodzenia ciep a desek pod ogowych bez otworów, z otworami
niewype nionymi oraz desek innych producentów. Najlepsze wyniki uzyskano dla desek z
otworami wype nionymi mas z opi ek aluminiowych, dla desek tych uzyskano wzrost
wspó czynnika przewodzenia ciep a o 24% w stosunku do desek bez otworów.
PIOTR POHL -Department of Woodworking Machinery and Basic of Machine Construction, Poznan University
of Life Sciences, 28, Wojska Polskiego Str, 60-637 Pozna , Poland
Rigidity of regenerated screw joints in pine wood
PIOTR POHL, MARCIN WO PIUK, PIOTR FORMELA
Department of Woodworking Machinery and Basic of Machine Construction,
Poznan University of Life Sciences.
Abstract: Rigidity of regenerated screw joints in pine wood. The study presents results of investigation
regarding the rigidity of regenerated screw-pinewood joints. The following two kinds of screws were examined:
EURO screws and conical screws mounted in three anatomical wood directions. Damage regeneration was
performed using three commercially available epoxy resins and an assembly glue. The obtained results showed
that in majority of cases, the regenerated connections were characterised by lower rigidity than the original
joints.
Keywords: rigidity, regenerated screw joints, pine wood
INTRODUCTION
The connection of elements in furniture industry and door and window woodwork is
commonly achieved by means of couplings with threaded elements. Examples of such
coupling elements include: mandrels of screw joints with cam-lever grips, various kinds of
screwed in bushes, regulated door hinges as well as screws and bolts. The advantage of these
connections is their disassemblability, fully or partially automated way of mounting as well as
durability resulting from the material (steel) from which the connectors are made.
The above-mentioned joints with the described connectors are of semirigid character
consisting in the occurrence of elastic-plastic deformations as a result of forces acting
between the connected elements and the connector. A characteristic feature of a semirigid
joint is its rigidity determined empirically. The rigidity of the joint is determined by linear
displacement characteristics s in the function of the external load change (force F)
(Modelowanie... 2004). Characterisation of a semirigid joint is presented in Fig. 1.
Fig. 1. Characteristics of a semirigid joint and method of determination of its rigidity (Modelowanie... 2004).
170
Excessively screwed or overloaded connecting elements weaken wood structure.
Repeated screwing in and unscrewing of connectors accompanied by a simultaneous cutting
in and compressing new coils of thread in wood by the connector thread coils wears out the
lead spiral hole in wood and, consequently, reduces the ability of holding of the connector
itself.
A damaged joint (torn out connector) can be repaired in many ways. Bearing in mind
the fact that the remedial actions should take into account both aesthetic as well as functional
aspects, one of possible measures is treatment of the damaged wood element with adhesive
material. Conservation work using epoxy composites was initiated in 1960s (Domas owski,
Powidzki 1968). Moreover, the effect of regeneration of screw joints on the capability of
holding screws in chipboard was also investigated (Pohl, Wo piuk 2010).
A number of experimental research results can be found in literature (Modelowanie...
2004; Dzi gielewski and Smardzewski 1995; Eckelman 1971, 1990; Još ák 1999) regarding
flexible (semirigid) joints at various states of loads of angle joints. However, there are no
research results concerning rigidity of regenerated joints. Therefore, it was decided to
investigate the effect of regeneration of screw joints on their rigidity.
REREARCH OBJECTIVE
The aim of investigations was to determine the impact of a screw joint regeneration
made in pine wood with the assistance of selected remedial agents on the rigidity of a flexible
joint.
Experiments were performed on samples of pine wood of 500 kg/m3 density and 6.7%
moisture content obtained from the same batch of material. Samples in the form of 50x50x50
cubes were cut out in a way which allowed measurements in three wood anatomical directions
(radial R, tangential T and longitudinal L). Investigations were carried out in the course of
tearing out conical screws 4x40 as well as EURO 6.3x20 screws. The connectors were
mounted to the depth of 15 mm with ±0.1 mm accuracy using a screwdriver into earlier
prepared holes 16±0.5 mm deep and the diameter equal to the diameter of the plain part of the
screw (conical – 2.4 mm, EURO – 3.9 mm). Measurements of the connector holding forces
and its displacement during tearing out were taken with the assistance of a testing machine
equipped in displacement induction sensors connected to a computer registering and
processing data. Employing the formula (Fig. 1), the rigidity of the non-repaired connections
pine-conical screw and pine-EURO screw was determined.
Regeneration of damaged screw-wood connections was carried out using Dragon
assembly glue as well as three epoxy resins known under the following commercial names:
Poxilin, Pattex Repair Express and Poxipol. The performed regeneration involved cleaning
the damaged place by removing wood residues and filling it with the above-mentioned agents.
After 24 hours, the excess of the applied material was removed and the surface was levelled.
Next predrillings were made and the connectors were mounted again. Rigidity measurements
of the regenerated joints were carried out in the same way as of the original ones.
RESEARCH RESULTS
Figure 2 presents successive phases of the experiment and the results of trials, which
are means of 5 replications, are shown in Figures 3 and 4. Figure 3 shows rigidity values of
the EURO screw-pinewood connection before and after regeneration, while rigidity values of
the conical screw-pinewood connection before and after regeneration are presented in Figure
4.
171
a)
b)
c)
d)
3974
3002
2873
2400
2545
3381
2749
2907
2392
2934
2372
3359
3305
2494
3099
4053
4412
4285
1943
2500
2000
1500
1000
2823
2937
5000
4500
4000
3500
3000
2706
Rigidity CF [N/mm]
5500
4726
5535
Fig. 2. Example phases of the course of the experiment: a) mounting of connectors in the sample; b) view of
damaged sample; c) treatment of the damage; d) tearing out of the connector from regenerated sample.
500
0
R
T
L
Assembly glue
R
T
L
Poxilina
R
T
L
R
Repair Express
EURO screw before regeneration
172
EURO screw after regeneration
T
Poxipol
L
4155
3629
3058
4116
3898
4637
5612
4997
4694
4416
3319
3213
2886
3000
2761
3776
4499
4836
4075
2813
3491
4000
3500
4426
5000
4500
3220
Rigidity CF [N/mm]
5500
4711
5593
Fig. 3. Values of rigidity of the EURO screw-pinewood connection before and after regeneration using different
preparations in three anatomical planes.
2500
2000
1500
1000
500
0
R
T
L
Assembly glue
R
T
L
Poxilina
R
T
L
R
Repair Express
conical screw before regeneration
T
L
Poxipol
conical screw after regeneration
Fig. 4. Values of rigidity of the conical screw-pinewood connection before and after regeneration using different
preparations in three anatomical planes.
The obtained research results of the rigidity of screw-pinewood joints showed
considerable variability. The tearing out in the regenerated samples occurred at the glue-wood
and not at the glue-screw contact which can be attributed to poor adhesion force of the glue to
the base – damaged wood. In most cases, a decline in rigidity of the regenerated screw-wood
connection was observed. These large inconsistencies could result from differences in
pinewood anatomical structure. For the examined EURO screws, repeatability of the rigidity
results in the repaired joints regenerated using the assembly glue, RepairExpress and Poxipol
could be observed. Every time, a drop in rigidity could be observed in radial and tangential
directions, whereas in longitudinal direction, rigidity was found to increase. This could be
attributed to pinewood anatomical structure.
CONCLUSIONS
x Rigidity of connections after regeneration with four remedial agents showed considerable
variability and, in general, was lower in all anatomical directions of pinewood than before
regeneration.
x Regeneration with the applied assembly glue showed increased rigidity in the case of
treatment of the damage after the EURO screw mounted in longitudinal direction and after
the conical screw in tangential direction.
x Poxilin gave good remedial results in the case of damage repairs after the EURO screws
mounted in tangential direction and after the conical screws in longitudinal direction.
x Application of RepairExpress for the regeneration of screw joints in pinewood increased
rigidity values for EURO screws mounted in longitudinal direction and for conical screws
in tangential and longitudinal directions.
x Regeneration with Poxipol is recommended for the longitudinal direction of mounting of
both connectors and for radial direction for conical screws.
173
LITERATURE
1. Domas owski W., Powidzki K. (1968): Badania nad zastosowaniem roztworów ywic
epoksydowych do impregnacji (wzmacniania) drewna. Acta Universitis Nicolai
Copernici, Zabytkoznawstwo i Konserwatorstwo, Nr 3.
2. Dzi gielewski S., Smardzewski J., (1995): Meblarstwo. Projekt i konstrukcja. PWRiL,
Pozna .
3. Eckelman C.A. (1971): Bending strenght and moment – rotation charakteristic of
twopin moment – rasisting dowel joints. For. Prod. J. 21, 3.
4. Eckelman C.A. (1990): „Wytrzyma o ciowe projektowanie mebli”, Wyd. SGGW-AR,
Warszawa.
5. Još ák P., (1999): Pevnostné navrhovanie nabytku. Tech. Univ. Zvolen.
6. Modelowanie pó sztywnych w z ów konstrukcyjnych mebli. (2004). red. Branowski
B. i Pohl P. Wyd. A.R. Pozna .
7. Pohl P., Wo piuk M. (2010): Investigations on the regeneration of screw joints in
chipboards. Annals of Warsaw University of Life Sciences - SGGW. Forestry and
Wood Technology No 70
Streszczenie: SztywnoĞü regenerowanych poáączeĔ gwintowych w drewnie sosny. W pracy
przedstawiono wyniki bada sztywno ci regenerowanych po cze wkr tów z drewnem
sosny. Zbadano dwa rodzaje wkr tów, wkr t typu EURO oraz wkr t sto kowy, osadzonych w
trzech kierunkach anatomicznych drewna. Regeneracji uszkodze dokonano przy u yciu
trzech ywic epoksydowych ogólnodost pnych na rynku oraz kleju monta owego. Wyniki
wykaza y, e w wi kszo ci przypadków regenerowane po czenia maj ni sz sztywno od
nienaprawianego po czenia.
Piotr Pohl, Marcin Wo piuk, Piotr Formela
Poznan University of Life Sciences,
ul. Wojska Polskiego 28,
60-637 Pozna , Poland.
tel: 0(48) 61 848 74 82, tel/fax: 0(48) 61 848 74 81,
Investigations on holding ability of screws in regenerated pinewood screw
joints
PIOTR POHL, MARCIN WO PIUK, PIOTR FORMELA
Poznan University of Life Sciences.
Abstract: Investigations on holding ability of screw in regenerated pine wood screw joints. In the course of the
performed experiments, screw holding capability in pinewood in repaired and original screw joints in three
anatomical directions was examined. The screw joint was made using conical and EURO screws most common
in mounting furniture hardware. Three kinds of epoxy resins and assembly glue were employed for regeneration
purposes. The performed investigations revealed that the holding capability of EURO and conical screws in
pinewood after regeneration was lower in comparison with original joints, on average, by 25% for EURO and by
15% for conical screws.
Keywords: holding capacity, joints, regenerated screw joints, pine wood
INTRODUCTION
One of the major construction issues in furniture industry is the selection of
appropriate joints in which the key role is played by connectors or fasteners (Wi niewski
1971). They should allow rapid assembly and disassembly of joints without negatively
affecting aesthetic values of both the connection and the entire piece of furniture.
Appropriately selected joints exert a decisive influence on the construction quality,
make relocation of elements in relation to one another impossible and increase strength,
rigidity and durability of the entire construction. At the present time, screw fasteners, e.g.
screws, are commonly used in furniture production.
Screws are usually employed in situations when joint disassemblability is required. At
present, screws replaced nails used for permanent connections. Screws are widely used in
furniture production due to their following traits (Durczak 1978): rapid assembly and
disassembly of joints, ease of the application of screws as connectors and possibility of
automation of mounting,
Disassemblable joints are also burdened with defects such as, for example:
x Weakening of the connection following repeated screwing in and out of fasteners,
x Possibility of damage of the material in which the fastener is mounted,
x Possibility of improper assembly by hammering in the screw,
x Dependence of the strength of joint on the direction of wood grain in relation to mounting
of the screw.
One of the measures of the screw holding capability is the force needed to overcome
the resistance of wood during the process of screws tearing out in the direction of their
longitudinal axis (Biniek 1994). This force depends on the following factors:
x Material in which the screw was set, its density and moisture content,
x Direction of the course of wood fibres,
x Size, shape and depth of mounted screws,
x Diameter of predrilling,
x Kind of the applied loads.
Screw joints are frequently subjected to damage, both in wood-derived materials and
in raw wood. Replacement of the damaged element of a piece of furniture is expensive and
sometimes impossible. However, there are several ways of allowing regeneration of damaged
175
joints without the need of replacing the damaged element and changing it to a new one (Pohl,
Wo piuk 2010), for example:
x Replacement of the originally mounted screw by a screw of greater diameter,
x Filling of the damaged hole with steel wool and then setting in the new screw,
x Filling the hole with a mixture of glue and fine wood dust,
x Drilling a new hole using a drill bit of greater diameter and gluing in a mounting peg.
At the present time, damaged joints are repaired using commercially available epoxy
resins which do not change their volume during hardening and frequently enhance strength
properties of regenerated connections without negatively affecting aesthetic value of a given
piece of furniture.
REREARCH OBJECTIVE
The objective of investigations was to ascertain which of the generally available
agents for regeneration of screw joints in pinewood was most suitable for this purpose and to
compare the strength of repaired and original joints
Bearing in mind widespread application of solid wood in furniture industry, in
particular in the manufacture of cabinet and skeleton furniture as construction and finishing
elements, a decision was made to conduct investigations on pine wood of 500 kg/m3 density
and 6.7% moisture content.
Experimental samples were obtained from one batch of raw material and were not
treated with any finishing materials to eliminate the influence of the finishing layer on the
research results.
Recommendations found in the standard PN-77/D-04227 “Investigations on the
holding capability of screws” were taken into consideration when selecting the size and shape
of experimental samples. In addition, kind and size of damages which can develop in solid
wood during tearing out of screws were also taken into account.
Experiments were conducted in the following three wood anatomical directions: radial
(R), tangential (T) and longitudinal (L).
Two kinds of screws most common in furniture industry to mount hardware were
employed: screws for wood with conical heads 4x40 as well as screws for wood EUROKOMBI 6.3x20. Predrillings to the depth of 16±0.5 mm were applied in the form of lead
holes with diameter equal to the diameter of the plain part of the screw (conical – 2.4 mm,
EURO – 3.9 mm). The holes were used to mount fasteners to the depth of 15±0.1 mm using
manual screwdrivers.
The screws were torn out in order to determine the capability of holding them in wood
and then destroyed wood tissue was removed from damaged samples and the losses were
filled using three kinds of agents based on epoxy resins of the following commercial names:
Poxilin, Pattex Repair Express and Poxipol as well as Dragon assembly glue. After 24 hours,
the excess of the remedial agent was removed using a file and sand paper. Predrilling lead
holes were made in the repaired samples and screws were screwed in and next measurements
were carried out to determine the capability of their holding in the regenerated joints.
Measurements of the screw holding capability in wood were performed in accordance
with the PN-77/D-04227 standard using for this purpose a testing machine (Fig. 2). The
machine allowed direct registration and analyses of the obtained results thanks to cooperation
with a computer.
176
Fig. 1. Sample shape and dimensions.
Fig. 2. Testing machine used in investigations.
The pulling out velocity used to determine the breaking force was established at
approximately 1 mm/s. The holding capability of screws (Zw) was calculated as a quotient of
the tearing out force to the length of screw setting with 1 N/mm accuracy.
1064
963
1005
729
623
648
496
613
684
733
678
500
489
569
719
722
888
996
1028
1123
1047
1060
932
790
1000
636
Holding capacity
Zw [N/cm]
RESEARCH RESULTS
Figures 3 and 4 present graphically holding capability of screws (Zw) in original and
regenerated screw joints. Figure 3 shows results for the EURO type screws and Figure 4 - for
conical screws. The results of screw holding capability are means from five measurement
replications.
0
R
T
L
Assembly glue
R
T
L
Poxilina
R
T
L
R
Repair Express
EURO screw before regeneration
T
Poxipol
EURO screw after regeneration
Fig. 3. Holding capacity for the EURO type screws set in pinewood.
R - radial direction, T - tangential direction and L - longitudinal direction
177
L
471
588
626
568
395
558
577
687
704
556
694
542
650
622
718
684
493
677
759
608
733
542
681
500
475
Zw [N/cm]
Holding capacity
1000
0
R
T
L
Assembly glue
R
T
L
Poxilina
R
T
L
R
Repair Express
conical screw before regeneration
T
L
Poxipol
conical screw after regeneration
Fig. 4. Holding capacity for the conical screws set in pinewood.
R - radial direction, T - tangential direction and L - longitudinal direction
In the majority of cases, the regenerated screw joints in pinewood exhibited lower
values of screw holding capability in comparison with the original joints. Pinewood was
characterised by the highest screw holding capability in the case of both EURO and conical
screws in tangential direction T. EURO screws were found to have the highest holding
capability after regeneration with the assembly glue in longitudinal direction L, with Poxilin
and Repair Express – in radial direction R and with Poxipol – in tangential direction T. On the
other hand, conical screws were found to have the highest holding capability after
regeneration with the assembly glue in longitudinal direction L and with Poxilin, Repair
Express and Poxipol – in tangential direction T. The observed decline of screw holding
capability in wood can be attributed to the fact that the agents used in experiments are
characterised by different structure as well as other physical and mechanical properties than
wood. During the tearing out process of screws, the damage did not occur at the contact line
of the screw with the regeneration agent but at the contact between the regeneration agent and
wood. This resulted in a significant decrease of the screw holding capability in wood after
regeneration in comparison with original joints. The results of investigations can be treated as
initial. It is necessary to continue experiments on the regeneration of screw joints in wood.
CONCLUSIONS
x EURO screw holding capability in pinewood before regeneration was by about 35%
higher in all wood anatomical directions in comparison with conical screws. This was
caused by differences in the diameters of the two types of screws. EURO screws had a
greater contact surface of the thread coil in wood than conical screws.
x The holding capability of EURO screws in wood after regeneration with epoxy resins
Poxilin, Repair Express and Poxipol dropped by about 35% in all wood anatomical
directions. In the case of conical screws, their holding capability decreased by about 16%
in all wood anatomical directions.
x The holding capability of EURO screws in pinewood after regeneration with the applied
assembly glue decreased by about 25% in radial and tangential directions and increased
by about 20% in longitudinal direction.
x The holding capability of conical screws in pinewood after regeneration with the applied
assembly glue decreased by about 30% in radial and tangential directions and increased
by about 20% in longitudinal direction.
178
LITERATURE
1. Biniek P., (1994): „Badania porównawcze zdolno ci utrzymania wkr tów o tych
samych parametrach wymiarowych mocowanych w drewnie i tworzywach
drzewnych”, Przemys Drzewny nr 9, 25-27.
2. Durczak J., (1978): „Wp yw wilgotno ci p yty wiórowej na zdolno utrzymania
wkr tów pod dzia aniem d ugotrwa ych obci e sta ych”, Typescript AR Pozna .
3. Pohl P., Wo piuk M. (2010): Investigations on the regeneration of screw joints in
chipboards. Annals of Warsaw University of Life Sciences - SGGW. Forestry and
Wood Technology No 70
4. Wi niewski G., (1971): „Próba ustalenia wp ywu obci e cyklicznych na zdolno
utrzymywania wkr tów i gwo dzi w p ytach wiórowych”, Typescript AR Pozna .
5. PN-77/D-04227: „Badania zdolno ci utrzymania wkr tów”.
Streszczenie: Badanie zdolnoĞci utrzymania wkrĊtów regenerowanych poáączeĔ gwintowych
w drewnie sosny. W pracy badano zdolno utrzymania wkr tów w drewnie sosny przed
regeneracj i po regeneracji uszkodzonych po cze gwintowych w trzech kierunkach
anatomicznych. Po czenia gwintowe wykonane by y przy u yciu wkr tów sto kowych i
wkr tów typu EURO najcz ciej u ywanych do osadzania oku meblowych. Do regeneracji
wykorzystano trzy rodzaje ywic epoksydowych i klej monta owy. Przeprowadzone badania
wykaza y, e zdolno utrzymania wkr tów Euro i wkr tów sto kowych w drewnie sosny po
regeneracji jest ni sza ni zdolno utrzymania wkr tów przed regeneracj o rednio 25% dla
wkr tów typu EURO i 15% dla wkr tów sto kowych.
Piotr Pohl, Marcin Wo piuk, Piotr Formela
ul. Wojska Polskiego 28,
60-637 Pozna , Poland.
tel: 0(48) 61 848 74 82, tel/fax: 0(48) 61 848 74 81,
Investigations on insertion forces of double-tee
joints into solid wood planks and wood-based boards
P. POHL1, K. RADZIKOWSKI2
1)
Department of Woodworking Machinery and Basic of Machine Construction, Poznan University of Life
Sciences, Poland
2)
Faculty of Transport, Warsaw University of Technology, Poland
Abstract: Investigations on insertion forces of double-tee joints into solid wood planks and wood-based boards.
The article presents results of investigations on forces needed to force into solid wood planks and wood-based
boards, without glue application, double-tee fasteners of ‘joint nail’ type in two connecting variants: at an angle
of 90o and 45o. The obtained values of assembling forces were described by diagrams for each of the applied
sample material: pine, oak, chipboard and MDF. The performed investigations showed that the highest pressingin force should be applied for oakwood. In the case of pinewood, these forces were by about 35% and for woodbased boards – by about 75% lower.
Keywords: joint nails, double-tee joints, wood-based board.
INTRODUCTION
Double-tee connections of joint nail type (http://www.jointnails.com) (Fig. 1) are
employed, primarily, to join solid wood but also wood-based boards. It is an inseparable type
of connection and in Poland it is applied, among others, in funeral industry.
Figure 1. Double-tee joint nail connection (http://www.jointnails.com).
A properly made connection of two boards requires making a kerf in each of them which
is 1-2 mm deeper than half of the width of the double-tee joint. This facilitates insertion and
assembly of the connection for which a pneumatic hammer is frequently applied. A
simultaneous application of glue (prior to hammering the joint nail in) makes the connection
stable, strong and invisible. In the technology of the described connections, a so called ‘initial
tightening’ takes place during assembly (Pohl at al., 2009) because the joint nail is
characterised by 1:100 tapering resulting in tightening of the assembled planks and exerting
an assembly clamp (Fig. 2).
180
Figure 2. Mechanism of the development of the initial tightening: a) joint nail hammered into elements, b) kerf
made in elements prior to assembly; F – hammering force of the joint nail, Fwst. – force of the initial tightening
[2]
RESEARCH OBJECTIVE
The aim of experiments was to determine forces necessary to assemble (insert) a doubletee connection of joint nail type in solid wood planks and wood-based boards. The forces are
directly associated with the initial tightening mechanism during the assembling process
caused by the tampering of the joint and are different for specific types of materials.
METHODOLOGY
Investigations were carried out on an angle joint presented in Figure 3. Each joint consists
of the following elements: two boards and two double-tee connectors of joint nail type.
Experiments were performed on samples prepared from the following materials: pine, oak,
chipboard – PW and medium density fibreboard – MDF. The above-described trials were
carried out for glueless joints.
Experimental planks and boards were made on a special numerically controlled
woodworking machine which guaranteed repeatability of kerf milling 1.3 mm wide. The
adopted dimensions of the assembled elements were as follows: 200x200x18 mm (Fig. 3).
The manufacturer recommends such choice of the connecting element that it should constitute
¼ of the board length per one connector (the gap between joint nails constitutes ½ of the
length of connecting edges) and, therefore, two 2’’ (50 mm) joint nails were applied.
181
Figure 3. Spatial model of the sample used in experiments.
Investigations on forces necessary to insert the joint were carried out on a Zwick 1445
type testing machine equipped in appropriate experimental paraphernalia (Sydor 2005). The
assembly of joint nails perpendicularly to the side of boards was performed on the testing
machine.
The first 10-15 mm of the joint nail was inserted into the board kerf manually and then a
pressure force F was applied until the joint nail was driven completely into the board. The
results of this operation are presented in diagrams of the dependence force F [N] on
displacement s [mm].
Experiments were carried out in two variants of the joint (Fig. 4):
x Variant a) – straight boards (without cuts - angle 90o),
x Variant b) – skew boards (with cuts at the angle of 45o).
Figure 4. Variants of the experimental joints: (a) straight boards (b) skew boards.
The total of 20 replications for each experimental variant was performed and then mean
values and standard deviations as well as ranges of errors at 95% level of confidence were
calculated.
RESEARCH RESULTS
Figure 5 presents example results obtained for 20 MDF board samples with straight
connection (variant a).
182
Figure 5. Results of examination of the insertion force of double-tee fasteners into MDF board without cutting
(variant a)
The performed analysis comprised the range of forcing in the joint nails to the depth of
35 mm because, as it was explained earlier, the first 10-15 mm of the assembly of the doubletee connector was carried out manually to insert the fastener into the kerf correctly.
On the basis of the research results, the mean curve of dependence force F –
displacement s was calculated and, in selected points, ranges of standard errors for 95%
confidence level were presented. The curves obtained in this way are presented in Fig. 6 in
forms of F - s diagrams.
183
Figure 6. Results of investigations of the insertion force of joint nail type fasteners (with confidence intervals
95%) in oak, pine, chipboard and MDF boards for straight and skew connections.
Figure 7 collates research results of insertion forces for both types of joints (variants a
and b) for all the examined materials.
Figure 7. Cumulative research results of insertion forces of joint nail fasteners
184
Analysing Figures 6 and 7 it can be concluded that, as expected, the highest insertion
forces occurred in oak samples and by about 35% smaller – in pine samples. Greater forces
were required to insert fasteners in the case of straight joints (variant a) and slightly smaller –
in the case of skew joints (variant b).
In the case of MDF and chipboards, the applied insertion forces were significantly
smaller and amounted to about 25% of forces used in oak samples and were slightly higher
for MDFs than for chipboards. In both of these materials, especially in the case of MDFs, a
very small scatter of research results as well as lack of differences between variant a and b
were observed. This is understandable bearing in mind the homogeneity of these boards.
CONCLUSIONS
The following conclusions were drawn on the basis of the obtained research results:
x The highest insertion force was required for oakwood, lower (by about 35%) for
pinewood planks and the lowest (about 25% of the force required for oak) – for MDFs
and chipboards,
x In the case of oakwood, a slightly higher insertion force was needed for straight joints
(variant a) than for skew joints (variant b) (the observed difference – about 10%)
x The examined wood-based boards showed similar values of insertion forces and
significant repeatability of results.
x For oak and pine woods, the course of dependence curves force – displacement was of
exponential nature. The examined wood-based boards were characterised by a linear
course of the dependence.
REFERENCES
1. B. BRANOWSKI i P. POHL: „Modelowanie pó sztywnych w z ów konstrukcyjnych
mebli”, AR, Pozna , 2004.
2. P. POHL, K. RADZIKOWSKI, M. WO PIUK: „Po czenia k towe drewna i p yt
drewnopochodnych przy u yciu z cz dwuteowych”, XXIV Sympozjon PKM
Bia ystok-Bia owie a, 2009.
3. M. SYDOR: „W a ciwo ci konstrukcyjne pó sztywnych k towych po cze p yt
drewnopochodnych ze z czami”, Politechnika Pozna ska, typescript, Pozna , 2005.
4. G. WIELOCH, M. SYDOR, P. POHL: „Wyznaczenie optymalnych no no ci i
sztywno ci wybranych meblowych pó sztywnych z cz k towych”, Politechnika
Koszali ska, Zeszyty Naukowe Wydzia u Mechanicznego nr 35, Prace XXII
Ogólnopolskiej Konferencji Polioptymalizacja i Komputerowe Wspomaganie
Projektowania, Mielno, 2004.
5. http://www.jointnails.com, 02.08.2010.
185
Streszczenie: Badania nad siáami wciskania záącz dwuteowych w páytach drzewnych i
drewnopochodnych. W pracy przedstawiono wyniki bada si wciskania
czników
dwuteowych typu joint nails, bez u ycia kleju, w p yty drzewne oraz drewnopochodne przy
dwóch wariantach po cze – pod k tem 900 i 450. Uzyskane warto ci si monta owych
opisano wykresami dla ka dego materia u próbki: sosny, d bu, p yty wiórowej i MDF.
Badania wykaza y, e najwi ksz si wciskaj c nale y stosowa dla drewna d bu, dla
drewna sosny si y te s o ok. 35% ni sze, a dla p yt drewnopochodnych o ok. 75 % ni sze.
Piotr Pohl,
28 Wojska Polskiego Str.,
60-637 Poznan, Poland,
tel: 0(48) 61 848 74 82, tel/fax: 0(48) 61 848 74 81,
Krzysztof Radzikowski
Faculty of Transport, Warsaw University of Technology,
75 Koszykowa Str.,
Tel: 0(48) 604 114 126
Competitiveness growth comparing to corporate social responsibility idea
on the basis of the timber industry (case study)
KORNELIA POLEK-DURAJ
Opole University of Technology
Department of Labour Market and Human Capital, 4 Wary skiego Street, 45-3701 Opole, Poland
Abstract: The article presents fundamental role of corporate social responsibility idea in the aspect of
competitiveness growth of a given organization on the basis of the timber industry. The timber industry
according to its various features such as: weak cash flow, its location or number of life threats is a specific
market and there is a need to act abiding the principles of CRS.
Keywords: Corporate social responsibility, timber industry, competitiveness
INTRODUCTION
Dynamic changes occurring in the world which are the consequence, both of technological
and organizational progress, as well as economic and social one, indicate that the social
responsibility is playing an important role in shaping image of the company, which wishes to
be reckoned on the market and creates sustainable social and economic development. Polish
entrepreneurs realize that their business activity should be based on solid and stable relations
with workers, suppliers, investors as well as clients, local community and government
administration. Therefore, the concept of social responsibility is gaining more and more
popularity and becomes the key element in strategic management. It plays an important role
in specific economic branches, which according to its various factors (financial, location),
have more difficulty in arising on the local market. One of them is a timber industry, and
especially sawmills, where European standards are realized improperly (in the field of
ensuring safe and decent working conditions or environmental protection), not to mention
anticipated activities desired by the surroundings.
The aim of the article is to characterize the idea of social responsibility and the timber
industry. The key element is also to present the correlation between social responsibility and
competitiveness growth in the timber industry.
THE IDEA OF CORPORATE SOCIAL RESPONSIBILITY
The idea of corporate social responsibility (CRS), also known as social responsible
business, is a concept commonly known in the world. The main assumption of CRS concept
is the fact that company functions as a coherent member of society. “CRS can be defined as a
conception, thanks to which companies are integrating with social and environmental aspects
of day-to-day activities together with stakeholders on the basis of voluntariness”1.
The proper realization of this concept generates significant benefits both for organization,
society and the economy. The most important benefits are: creating positive opinion and
image of the company, improving working conditions and life conditions, possibility to
acquire new clients and investors, development of human resources, improving natural
1
M. emig a, Spo eczna odpowiedzialno przedsi biorstwa, Oficyna Wolters Kluver business, Kraków 2007
za European SMEs and social and environmental responsibility [w:] Observatory of European SMEs 2002, nr 4,
s. 11.
187
environment and most of all increasing competitiveness on the global market at the same time
forming good conditions for sustainable economic and social development.
POLISH WOOD INDUSTRY
The sawmill industry is one of five fundamental branches in the timber industry in Poland.
It plays an important role, the finished products of sawmills are used not only in the other
branches of economy (such as mining or building industry) but also in various timber industry
branches.
The characteristic feature of polish sawmill industry is vast localization of sawmills,
mainly located in the rural areas with large number of constantly changing entities, especially
small companies with low production. Nowadays, the sawmill industry is the branch of the
timber industry that is systematically and intensively developed. According to National
Economy Register, the number of economic subjects operating in the sawmill industry after
the transformation process in the early 90’s, has dropped drastically at first and then raised up
to 12%, and has been at the same level from several years (in 2008 it was almost 8500
entities). The new firms have been mostly established in four polish regions: mazowieckie,
podkarpackie, lubelskie and wielkopolskie. In Opole region, there is the smallest number of
such firms, even though around 13% of firms is situated in this region of Poland. However the
overall number of sawmills operating on polish market is fluctuating between 1200 and 1400
firms. Most of them, are small factories, only 15% of them have been employing more than
49 people, and the consortiums are rather unusual.
Unfortunately the general situation in this branch of economy is rather unsatisfying. This
situation is surprising bearing in mind that the timber industry from the early stage of Polish
transformation is characterized by huge financial and economic problems. Mainly it is caused
by utter reorganization of sawmills in the mid nineties. Until that time, the market had been
dominated by more than 30 large enterprises, located in a group in one region. The central
managing of them was practically impossible. Usually, the profits from cost-effective entities,
instead of increasing the productive and investing abilities of that particular entities, were
directed and transferred to enterprises with loses which gain no profit in future. After
abolishing command economy, the firms from the timber industry were unable to conduct
proper reorganization and in the end they ceased to exist. Most of companies had been already
bankrupt and the only rational solution was to close the company. Filling the gap in the
market, more small and medium companies were established. They used the old buildings of
closed sawmills or other rural buildings. The launching of new businesses occurred after
several months of downtime, when most of the property had been already sold out during the
auctions, and the best workers had found new job. Currently working sawmills in comparison
to those from pre-transformation period can be characterized by limited production (around
200-300 m3).
Beyond the changes that had already occurred, the key issue for apt functioning of this
branch of economy, will be high prices of lumber. Currently it is one of fundamental
problems for production plants, as in the structure of overall costs around 55% of all cost goes
to purchase of lumber. The main supplier of wood for polish market is the State Forests
National Forest Holding, which possess approximately 78% of all lumber in Poland (where
publicity owned forests makes 82%, the rest are private forests). This organization has an
ability and power to influence over the structure of polish wood market by shaping the supply
of material, which final price, from 2006, is being established on e-portal called E-wood,
where wood from all polish forest inspectorates is sold. In this form, the sale is based on three
stages. In first two stages the forest inspectorate offers the given material and its final minimal
price. Then buyers are placing their offers. The best chances in this stage have the companies
which are operating on polish market for few years and previously have already bought the
188
wood in this way. The different situation is in the third stage, where on the internet auction
one can buy wood previously not sold. In this way, the price of wood is created during the
bidding, so the price is higher than in the first or second stage, but everyone can purchase it.
Currently, the last method is the most popular way of buying lumber. However it is not
profitable for all buyers, especially those small companies which cannot raise the price. But
still this method is far way better than in previous years, when producers had given amount of
wood to buy and the price was usually very high, established by the State Forests National
Forest.
Additionally, bad financial situation of timber industry was cause by disability to self-finance
the investments and modernization, in order to enlarge the business activity and low interest
of foreign capital in investing into this branch of economy. These factors have fundamental
impact on low level of company’s engagement into the idea of social responsibility, especially
in the aspects desired and expected by the society.
Apart from financial problems in the timber industry, there have also appeared
organizational and technical problems. They stem from low level of occupational safety and a
number of accidents at work and inappropriate work organization from the point of view of
employees (irregular usage of occupational safety rules – according to self-study over the
quality of working conditions, conducted in chosen companies form the timber industry in
2004 and 2009, noted only 11% in the growth of systematical usage of means of individual
protection, currently it is only 66%) and employer (use of obsolete machines).
In Poland, like in many other European countries, the workers from woodworking
companies and carpentry business are among 10 professions which are characterized by the
highest level of possibility of occupational accidents. The highest number of work accidents is
noted while working with sawing machines, millers and shaping machines. The main work
injuries are: hand injury, palm injury and injury of abdominal cavity.
In spite of various adversities occurring in the timber industry, that generate its specific
character, many producers after 2000 were able to arise on the market and achieve success.
Some foreign investments into polish market were also noted, they positively influence the
image of polish sawmills and increase of their profitability.
CRS IN THE ASPECT OF COMPETITIVENESS GROWTH IN THE TIMBER INDUSTRY
(CASE STUDY)
The level of implementing CRS idea is dependent on many factors. In polish reality,
crucial meaning apart from financial situation of the company, have also education and
promotion of CRS, as the level of knowledge in this subject is insufficient. The good
knowledge of social responsibility idea is a characteristic feature of big concerns, usually with
foreign capital, and the study confirms that phenomenon. Small and medium companies rarely
take an action in social activities, as the entrepreneurs usually assume that the costs of those
actions are too high and unprofitable. This attitude towards social responsibility idea is
improper as the costs of actions are not easily reimburse in near future, but they do bring other
various benefits for company, the society and economy in long-term aspect.
The analyzed production plant from timber industry is situated in Opole region. Until the
restructuration that had been conducted in 1997, the plant was a part of central Opole Wood
Industry in Opole, and then after 1997 it has been converted into a joint-stock company under
the name Opole Wood Industry OPDREW, created by its employees and strategic investor. In
this form, the company stayed on the market until 2001, when due to improper decisions of
main investor, declared bankruptcy. The production plants belonging to OPDREW were put
up for sale. In 2002, the analyzed company was purchased by the legal adviser of Wood
Industry Plant Ltd. Unfortunately; the company still had many problems, starting from
financial and ending on problems with gaining lumber, low level of quality of working
189
conditions, low workers engagement, problems with acquiring new clients and creating the
positive image. Due to these factors the position on the market ceased to be competitive.
Therefore, the company started to look for strategic partner, who would invest in
modernization of the plant and at the same time enhance development of Opole region. At the
end of 2006 the company was purchased by Swedish-Finnish corporation which was an
integrated company dealing with processing of lumber, production of paper and products
environmental friendly, with high quality products produced in safe working conditions. The
concern has been undertaking various actions in the field of social responsibility in number of
its plants around Europe, which enables to keep good position on the market. In surveyed
plant, after taking over, the first concern was to undertake proper actions required by the
standards of European Union in the field of:
x Safety and health of workers (the formal safety policy has been implemented; it was design
as a system of practical tools used for constant development and improvement of situation
in corporation’s plants. It helps to ensure acceptable level of risk and to apply the best
available technical and organizational knowledge in order to prevent work accidents,
occupational diseases and to identify forthcoming risks. The systems works according to
international norms of quality concerning the safety and health protection OHSAS 18001,
BS 8800).
x Environmental protection (the policy has been implemented in the form of formal
document, the systematical trainings in the field of norms ISO of 14000 series have been
introduced).
x Improvement of quality of finished goods (all finished goods have a system of verification
– Chain-of-Custody, thanks to which it is known that the wood comes from certificated
forests).
x Consumer protection (the plant has the system of safety of final goods).
It is worth underlining that actions undertaken in first two areas have significant meaning and
impact over shaping of life quality, which takes important position among social targets.
Moreover, the company has also been undertaking various entrepreneurial activities
allowing functioning according to social responsibility idea. The most important issue to
implement was to introduce the ethical code of running the business (the trainings in that field
were introduced for managers and employees) and social engagement by supporting local
cultural or sport events.
Management staff and workers of this plant, thanks to proper and regular trainings and good
flow of information, are conscious of all aspects of social responsibility and its positive
influence. The experience of the foreign investor, who for years has been running the business
in the light to CRS in all his companies around Europe, played an important role in this
process.
On the basis of twofold surveys that were conducted in polish plant (first one in April
2004, second in December 2009) and data analysis it can be assumed that from the moment of
implementation of new rules in 2007, some significant changes for organization and its
workers can be noted. Among them, the most important ones are:
x increase of workers motivation and engagement, at the same time increase of their
efficiency,
x higher level of organizational culture and improvement of company’s image,
x increase of business efficacy,
x better competitiveness on the local and foreign market ( the general sale of final goods has
increased three times, and significant growth of exporting goods was also noted, from
10% up to 40%),
x recruitment of new clients and deepening of loyalty.
190
CONCLUSION
Implementation of social responsibility concept into companies is more and more popular,
and at the same time indispensible. This process takes on institutionalized forms in European
countries as well as in the structures of European Union, becoming a new international trend.
Activities undertaken in the field of CRS have become a strategic and priority element of an
international policy. Abiding the idea of social responsibility is indispensible factor of every
organization that wishes to be reckoned on the national and international market. Thanks to
creating proper attitudes in all aspects of social responsibility the organizations are more
flexible and can perform better on the market that is constantly changing, as well as undertake
new challenges easily.
On the basis of this analysis it can be assumed that functioning according to CRS concept
brings significant benefits for the organization, workers and local environment. The
confirmation of that is growth of competitiveness on the global level, which is especially
important in discussed branch of the timber industry. Presented sawmill can be a good
example for other firms which wishes to perform according to principles of sustainable socioeconomic development.
REFERENCES
1. Adamczyk J., Spo eczna odpowiedzialno przedsi biorstw. Teoria i praktyka, PWE
Warszawa 2009.
2. Polek – Duraj K., Warunki pracy w przemy le l ska Opolskiego ze szczególnym
uwzgl dnieniem przemys u drzewnego i cementowego, OFPO, Opole 2007.
3. Berman S., Jonem T., A.C. Wicke, Convergent Stakeholders Theory [w:] Academy of
Management Reviev 1999, no 24.
4. emig a M., Spo eczna odpowiedzialno przedsi biorstwa, Oficyna Wolters Kluver
business, Kraków 2007 za European SMEs and social and environmental
responsibility [w:] Observatory of European SMEs 2002, no 4.
Streszczenie: W niniejszym artykule przedstawiono znaczenie spo ecznej odpowiedzialno ci
w aspekcie wzrostu konkurencyjno ci przedsi biorstwa w przemy le tartacznym. Na
przyk adzie wybranego zak adu przerobu drewna starano si ukaza korelacj pomi dzy
dzia aniami podejmowanymi w ramach CRS, a popraw sytuacji zak adu prowadz c w
konsekwencji do coraz to lepszej pozycji na rynku.
Opole University of Technology
Faculty of Management and Production Engineering,
Department of Labour Market and Human Capital
45-370 Opole, Ul. Wary skiego 4, Tel. (77) 453 04 072 w. 36
(Ann. WULS-SGGW, For and Wood Technology. 72, 2010)
Analysis of the heat release rate from wood with applied fire protection by
selected flame retardant agents
MARZENA PÓ KA, MAREK KONECKI
Department of Combustion and Fire Theory – The Main School of Fire Service, Warsaw – SGSP
Abstract: Analysis of the heat emission rate from wood with applied fire protection by selected flame retardant
agents. From the very beginning of our civilisation wood – a flammable material has been in use as a basic
construction material. The spectrum of fire retarding impregnating formulations and their increasingly
widespread application impose carrying out of research relating to their impact on flammable properties of
different wood types. This paper comprises a comparative analysis of the efficacy of selected fire protection
formulations, implemented by testing the rate of heat emission from selected wood samples at external heat
exposure equal to 30kW/m2. The applied thermal exposure simulates heat and flow conditions, which take place
in the incipient stage of the fire.
Keywords: fire hazards, flame retardant for wooden, heat release rate.
INTRODUCTION
From the very beginning of our civilisation wood – a flammable material has been in
use as a basic construction material. Light framework construction widespread in Poland and
worldwide offers an excellent option for buildings of mineral materials, which are relatively
difficult in the construction process, and also quite costly. Buildings of brick and concrete
also comprise elements made of wood. The examples cover roof truss systems, staircases,
architectural elements in the form of flooring, wall panelling, ceilings or furniture. Wooden
elements may lead to a fire risk in a structure, hence prevention and physical protection
methods of wooden elements in buildings are highly recommended. Chemical wood
protection methods still tend to remain the most effective methods of fire proof wood
protection. Wooden elements, protected with flame retardants, are less susceptible to
inflammation, and consequently need a bigger thermal flux or longer time of its action.
At present the Polish market offers several dozens of various flame retardants
(antipyrenes). They are available as salt granulates, liquid agents ready for surface and deep
application, paints, varnishes or fire resistant mass. The action of antipyrenes varies, yet in the
majority of cases it is based on protecting wood from fire, house fungi, mould and insects. In
their recommendations the producers present the general designation of their formulations,
their chemical composition, application method and output. However, in many cases there is
insufficient information related to effectiveness. Frequently the customers tend to ask
themselves – what should be borne in mind when buying a flame retardant and whether the
price is adequate to the effectiveness?
The spectrum of fire retarding impregnating formulations and their increasingly
widespread application impose carrying out of research relating to their impact on flammable
properties of different wood types [1-7]. This paper comprises a comparative analysis of the
efficacy of selected fire protection formulations, implemented by testing the rate of heat
emission from selected wood samples at external heat exposure equal to 30kW/m2. The
applied thermal exposure simulates heat and flow conditions, which take place in the incipient
stage of the fire.
192
DESCRIPTION OF RESEARCH MATERIAL AND OF ANTIPYRENES
The tests were carried out on dried seasoned oak wood samples with a density not
exceeding 0.80 g/cm3. Flame retardant modification comprised two-fold application of the
antipyrene, the volume and procedures of which are specified by the producer of formulations
applied in our research. Choice of the application method (brush or spray) of flame retardants
arises from the most common practical application of the formulations in construction
industry.
The following flame retardants available on the market have been applied for flame retardant
modification of oak wood samples:
x Fobos,
x Uniepal,
x Prevento,
x Ogniochron.
TEST METHOD - CONE CALORIMETER METHOD ACCORDING TO ISO 5660
To perform analysis of heat and smoke release rates for wood samples a cone
calorimeter manufactured by FTT (Fire Testing Technology) from Great Britain was used (it
is available at Combustion Institute of the Main School of Fire Service. The tests were
performed according to the ISO 5660:2002 standard [8].
Although the theoretical base of the cone calorimeter has been known for a few dozen years,
the first standardized method of determining fire properties was developed in the middle of
90'. In 1917 Thornton [9] proved that significant number of organic fluids and gases exposed
to heat fluxes release constant amount of heat per unit of mass of oxygen used for complete
combustion of a flammable substance. Huggett [10] verified this dependence for the solid
bodies and found that heat released during combustion of solid bodies is proportional to the
amount of oxygen required to burn a unit of mass of a flammable material. In case of most
flammable materials to which one can include wood, plastics, organic fluids and other
flammable materials, this dependence defines that for every kg of consumed oxygen during
combustion time 13,1 MJ of heat is released. Deviations from average value reach (on
average) ±5% for different materials. Thus, 13,l MJ of the released heat was assumed as a
constant unless more precise data are available.
RESULTS
Results of testing for wood samples not modified by flame retardants and with added flame
retardants (an average obtained from 3 measurements) were shown in table 1.
ANALYSIS OF THE RESULTS OF EXAMINATION OF THE THERMOKINETIC AND
THERMOPHYSICAL PROPERTIES OF STUDIED MATERIALS – CONCLUSIONS
Basing on the performed research of materials produced from unmodified oak samples and
those modified by flame retardants, the following presumptions can be made:
x Flame retardants introduced to tested wood effectively reduced the heat release rate as
compared to the unmodified wood material.
x The lowest values of HRRmax were obtained for oak + ogniochron (brush) at the applied
heat exposure.
193
x
x
Average heat release rates for the modified materials were by 10–20% smaller than HRRav
of the unmodified material. The lowest HRRav value was obtained for oak +prewento
(brush)
When applied by a brush at 30 kW/m2 on oak they reduced the time to ignition of the
flammable gaseous phase very slightly ca. 2.3 times. This proves that products of thermal
decomposition and combustion obtained from oak = prevento inhibit the moment of
igniting gaseous phase. Prevento in tested wood acts as an antipyrene mainly in gaseous
phase.
Tab 1. Results of testing for wood samples not modified by flame retardants and with added flame retardants
(an average obtained from 3 measurements) at 30 kW/m2
The way
applied of HRRmax
HRRĞr
MLRĞr
t ignition
SEAĞr
TSR
Samples
flame
[kW/m2]
[kW/m2]
[g/s]
[s]
[m2/kg]
[m2/m2]
retardant
Unmodified
oak sample
193,91
73,41
0,052
68
16,76
60,93
Fobos
brush
236,13
68,50
0,041
107
78,33
254,92
spray
185,54
77,67
0,050
114
51,23
165,75
Uniepal
brush
62,95
0,045
72
45,23
171,13
spray
224,82
87,67
0,071
77
47,89
176,49
Prevento
brush
208,12
55,89
0,035
146
27,67
113,05
spray
215,27
99,98
0,074
144
32,29
98,31
Ognioochron
brush
181,40
61,40
0,040
109
49,44
177,52
x
x
x
x
x
x
Introduction of the applied flame retardant at the density of external heat flux equal to 30
kW/m2 extended the time to ignition for the unmodified oak. This implies that products of
decomposition and combustion released from those modified samples effectively inhibit
the moment of ignition of the gaseous phase, and the mechanism of operation is active
primarily in the gaseous phase. Thermal decomposition products of the modified oak
samples dilute the flammable gaseous phase and undergo chain-radical reactions that
reduce the energy of the radicals responsible for propagation of the flame combustion. At
50 kW/m2, the best combustion inhibitor operating in the gaseous phase of Ep 561 was
melamine, since in its case the time to ignition was longer than for other flame retardants
(next were: UEp 561 + Roflam P and UEp 561 + Roplast FN-1.
While considering Total Smoke Release (TSR) it can be asserted that the applied flame
retardant increases the smoke release rate at the tested heat exposure. The lowest value of
TSR was observed for oak +prevento (spray) among the tested modified oak samples.
The lowest value of SEAav and TSR was obtained for unmodified wood samples. It means
that the applied flame retardants increase smoke generation during the fire as compared to
unmodified oak.
As to emission of CO from 1kg of a material it was found that the lowest CO value was
for oak + uniepal (spray).
As regards CO2, it was observed that at 30 kW/m2 oak + uniepapal (spray) indicated the
lowest CO2 emission as compared to the other investigated materials produced from oak.
The application of the applied flame retardants using a brush led to obtaining lower
HHRav values as compared to the application of the same agent onto an oak wood ample
but with spraying. This dependence has been observed for all samples impregnated with
flame retardants.
194
x
x
Uniepal applied by spraying on an oak wood sample generated the lowest emission of CO
and among the retardants and thermal exposure.
The highest level of CO among flame retardants applied in testing was generated by
Ogniochron, while the biggest volume of CO2 was generated by Fobos applied by rush on
oak samples.
REFERENCES
1. V. Babrauskas, Ignition Handbook: Principles and application to fire safety
engineering fire investigation, risk management and forensic science, 2001.
2. B. Karlsson, J.G Quintiere, Enclosure fire dynamice. Wyd. CRC Press LLC., USA
2000.
3. G. Jankowska, W Przygocki, A W ochowicz, PalnoĞü polimerów i materiaáów
polimerowych, Warszawa 2007.
4. D. Drysdale, An introduction to Fire Dynamics, John Wiley and Sons, New York
1985.
5. Ch.A. Wilkie, Fire Retardancy of Polymeric Materials, Mercel Dekker AG, Basel
2000.
6. V. Babrauskas, S. J. Grayson, Heat Release in Fires, Chapman & Hall, London
1995.
7. J. Troitsch, International Plastics Flammability Handbook, Hanser Publications,
Munich 1990.
8. ISO 5660: 2002, Reaction to fire test – Heat release, smoke production and mass
loss rate, Part 1: Rate of heat release from building products, Part 2: Smoke
production rate (dynamic measurement) – Cone calorimetric method.
9. W. Thornton, The relation of oxygen to the heat combustion of organic
compounds, „Philosophical Magazine and J. Science”, 1971, nr 33, s. 196.
10. C. Huggett, Estimation of rate heat release by means of oxygen consumption
measurements, „Fire and Materials” 1980, nr 4, s. 61–65.
Streszczenie: Analiza szybkoĞci wydzielania ciepáa z drewna zabezpieczonego ogniochronnie
wybranymi Ğrodkami ogniochronnymi. Drewno – materia palny, ju od pocz tku naszej
cywilizacji by o stosowane jako podstawowy materia budowlany. Spektrum impregnatów
przeciwogniowych oraz ich coraz powszechniejsze zastosowania, zmuszaj do prowadzenia
bada dotycz cych ich wp ywu na w a ciwo ci palne ró nych rodzajów drewna. Niniejsza
praca jest analiz porównawcz skuteczno ci wybranych rodków ogniochronnych,
zrealizowanym poprzez badanie szybko ci wydzielania ciep a z wybranych próbek drewna
przy zewn trznej ekspozycji ciep a 30kW/m2. zastosowana ekspozycja cieplna symuluje
warunki cieplno – przep ywowe zachodz ce w i fazie rozwoju po aru.
Badania przeprowadzono w ramach POIG.01.01.02-10-106/09-01
Marzena Pó ka
Szko a G ówna S u by Po arniczej
Zak ad Spalania i Teorii Po arów
ul. S owackiego 52/54, 01-629 Warszawa
[email protected]
Innovative Processes in the Polish Wood Industry in the Years 2005 – 2009
W ODZIMIERZ POPYK, EL BIETA MIKO AJCZAK,
KATARZYNA MYDLARZ
Department of Economic and Wood Industry Management, Pozna University of Life Sciences
Abstract: Innovative processes in the Polish wood industry in the years 2005 – 2009. The article presents the
diagnosis of innovation activities in wood and furniture industries. The analysis of innovative processes in these
branches was made from the point of view of financing of R&D activities, direction and scope of innovativeness
and their influence on market outcome.
Keywords: innovativeness, wood working industry, furniture industry
INTRODUCTION
In the conditions of advancing globalization processes, competitive position of national
economies to a large extent depends on the ability of industrial enterprises to introduce
innovative solutions in their production processes. During their constant battle for consumers
they are forced to introduce solutions improving the quality of products and services. Despite
the fact that innovative activity is an expensive procedure, currently it is one of the basic
activities indispensable to survive and develop further in the conditions of more and more
”tight” market. A company perceived as innovative has a better capacity to reach competitive
edge. It is better perceived on the market. It is also characterised by better ability to generate
profit. Proper development of the innovative sphere in a company also gives a better basis to
plan long-term economic development.
INNOVATIVENESS AND ECONOMIC POLICY OF THE EU
Successful development of innovativeness is at present one of the priorities of the
economic policy of the EU countries, including Poland. The ”Innovative economy”
Operational Program approved for implementation by the European Commission in 2007 is
an important document regulating innovative activities.
To increase innovative activities of the Polish economy, the government adopted the
“Innovative economy” Operational Program [IEOP] that was developed within the National
Strategic Reference Framework for the period of 2007-2013 [5]. The aim of this program is,
first of all, direct financial support of innovative activities of economic entities, public
administration and scientific and research institutions. It concerns not only supporting specific
activities in already existing companies, but also creating new innovative ones.
Successful implementation of this program is a real chance for shortening the distance
between modern, high-technology economic entities of west-European countries and Polish
industrial companies, that in majority have outdated technical and technological machinery,
small percentage of new products introduced on the market and management systems of low
effectiveness.
The level of financial resources allocated for the development of innovativeness also
reflects serious approach to solving the innovativeness problem. Poland allocated more than
9.71 billion euro for this purpose. Community assistance through the European Regional
Development Fund (ERDF) amounts to €8.25 billion, and the remaining 1.46 billion comes
from the national budget.
196
EXPENDITURES ON RESEARCH AND DEVELOPMENT ACTIVITY
Despite the intensification of innovative activities in the Polish economy and
allocating substantial funds from the EU sources, processes in this sphere show low
dynamics. The important factor slowing down the development of innovativeness is limited
possibility for generating own financial sources for financing R&D activities, that are thought
to be one of more effective source of financing innovation. [4]. Poland is characterised by
large disparities in the structure of R&D financing compared to the leading EU countries. In
the EU the majority of R&D financing (60-70%) comes from non-public sources. The
majority of sources for this purpose (about 60% in 2007) comes from the state budget. R&D
financing by economic entities in Poland constitutes only 25% of the total financial resources
[2, 3].
Huge risk and belief that R&D activities are of low efficiency in the Polish conditions,
as well as long duration of the process, lead to relatively low level of investment of industrial
enterprises in R&D. It refers also to wood and furniture enterprises.
expenditures in mln PLN
70
60
50
Manufacture of wood and wood
products
Manufacture of furniture
40
30
20
10
0
2005
2006
2007
2008
2009
Fig.1. Intramural expenditures on R&D activity in wood and furniture industry in the years 2005-2009
Source: author's evaluation on the basis of CSO's data
Expenditure on R&D is a significant but still small element of innovative activity of
Polish wood enterprises (fig 1.). The sum spent on R&D in wood industry changed from 4.9
million PLN in 2005 to 7.2 million in 2009. The lowest level of investment on R&D in this
sector was observed in 2006, when only 2.7 million was spent.
Financing of R&D activity in the furniture sector is a little higher and generally, since
2007, it has been rising. In 2007 expenditure on this purpose showed the maximum level – 66
million PLN. In the next years significant reduction of expenditure on R&D was observed, in
2008-2009 this expenditure ranged from 8 to 10 million PLN.
Despite quite diversified trends in the R&D spending, general funds allocated for
innovative activities in products and processes in wood industry in the consecutive years were
similar and amounted to 380-420 million PLN (Fig. 2). In the furniture industry, despite the
crisis in the recent years, expenditure on R&D increased considerably from 494 million in
2005 to 869 in 2008.
197
expenditures in mln PLN
1000
800
Manufacture of wood and wood products
600
400
200
0
2005
2006
2007
2008
Fig.2. Expenditures on innovation activity for product and process innovations in wood and furniture industry in
the years 2005-2008
Source: author's evaluation on the basis of CSO's data
THE CHARACTER OF INNOVATIVE PROCESSES
The directions and level of expenditure of financial resources on innovative activity of
wood and furniture industry reflect the technological character of innovation.
manufacture of
furniture
30
30
25
25
interprises in %
interprises in %
manufacture of wood and wood
products
20
15
10
5
20
15
10
5
0
0
2004-2006
2006-2008
2004-2006
products
2006-2008
processes
Fig 3. Share of enterprises which introduced new or significant products and processes in wood and furniture
industry.
Source: author's evaluation on the basis of CSO's data [1,2]
A characteristic feature for wood industry is the dominance of process innovation over
product innovation (fig. 3). The percentage of companies of wood industry that introduced
process innovations in the years 2006-2008 amounted to 25%, in the case of product
innovation it was 18%. Wood companies introduced more innovations concerning the
production process than new products. The character of introduced innovations in furniture
industry is similar to European trends, where product innovations dominate. In the years
2006-2008 the percentage of companies that introduced process and product innovations was
comparable and amounted to 25%.
In the structure of expenditure on innovation of Polish wood and furniture enterprises
dominate expenditure on investment. This fact reflects constant need to modernise technical
and technological machinery of production companies as well as modernisation and
development of production sites and distribution and sale points.
198
% of sold production of products
30
25
20
15
10
5
0
2005
2006
2007
2008
2009
Manufacture of wood and wood products
Fig. 4. Share of sold production of new and modernised products in wood and furniture production
Source: author's evaluation on the basis of CSO's data [1]
The results of innovative activity are reflected by the share of sold production of new
and modernised products in the total production sold (fig.4). The domination of process
innovation in wood industry is shown by low level of new and modernised products sold
(about 8%). The results of furniture industry in this respect are much better. Due to
sustainable investment in product and process innovations the share of sale of innovative
products in furniture industry is much larger. After systematic increase in the recent years, in
2009 the share if new and considerably improved products rose to 25%
CONCLUSIONS
The position of industrial enterprises in the present economic environment to a large
extent depends on the proper development of innovative activity. The development of
innovativeness is not possible without proper financing of R&D and tight cooperation of its
units with industrial entities.
The level of R&D financing in the Polish wood industry is far from the desired one.
The result is a limited scope of innovative activities and low share of innovative enterprises in
these branches compared with the Western Europe.
Contrary to European tendencies, where product innovations dominate, in the Polish
wood industry these are process innovations that dominate. The furniture industry shows a
little better results in this respect. Sustainable development of process and product
innovations in this branch is reflected in the increase of sale of innovative products.
The main obstacles in the innovative activity according to the opinion of the
entrepreneurs are limited possibilities of financing, especially from the own resources of the
enterprises, high costs of innovation, considerable risk connected with implementation of
innovation, lack of interest of buyers in new products.
REFERENCES
1. Rocznik statystyczny przemys u [Statistical Yearbook]. 2005-2009, GUS, Warszawa
2. Nauka i technika [Science and Technology]. 2004, 2008. GUS, Warszawa
3. Dzia alno
innowacyjna przedsi biorstw przemys owych w latach. Notatka
informacyjna 2005-2007 GUS [Innovative Activity of Industrial Enterprises in the
Years 2005-2007, Informational Note of Central Statistical Office], Warszawa
4. Wojnicka E., Klimczak P.: Procesy innowacyjne w sektorze MSP w Polsce i
regionach [Innovational Processes in SMEs in Poland and the Regions].
Innowacyjno 2008. PARP, Warszawa
199
5. Szczegó owy opis priorytetów Programu Operacyjnego Innowacyjna Gospodarka,
2007-2013 [Detailes of the priorites of Innovative Economy Operational Programme
2007-2013].Ministerstwo Rozwoju Regionalnego, Warszawa, 2009.
Streszczenie: Procesy innowacyjne w polskim przemyĞle drzewnym w latach 2005-2009. W
pracy przedstawiono ocen dzia alno ci innowacyjnej przedsi biorstw przemys u drzewnego i
meblarskiego. Analiz procesów innowacyjnych w tych bran ach dokonano pod katem
wielko ci finansowania sfery B+R, kierunków i zakresu dzia a innowacyjnych oraz ich
wp ywu na efekty rynkowe.
W odzimierz Popyk
60-627 Pozna ,
Poland
El bieta Miko ajczak
60-627 Pozna ,
Poland
Katarzyna Mydlarz
60-627 Pozna ,
Poland
Annals of Warsaw Unversity of Life Sciences-SGGW
Foresty and Wood Technology No 72, 2010: 201-205
(Ann. WULS-SGGW, For. and Wood Technol, 72, 2010)
ȼɥɢɹɧɢɟ ɨɫɧɨɜɧɵɯ ɪɟɠɢɦɨɜ ɪɟɡɚɧɢɹ ɧɚ ɲɟɪɨɯɨɜɚɬɨɫɬɶ ɨɛɪɚɛɨɬɚɧɧɨɣ
ɩɨɫɥɟ ɮɪɟɡɟɪɨɜɚɧɢɹ ɩɨɜɟɪɯɧɨɫɬɢ ɫɵɪɨɣ ɩɥɢɬɵ MDF
,
,
,
- SGGW
ɂɡɥɨɠɟɧɢɟ: ȼɥɢɹɧɢɟ ɨɫɧɨɜɧɵɯ ɪɟɠɢɦɨɜ ɪɟɡɚɧɢɹ ɧɚ ɲɟɪɨɯɨɜɚɬɨɫɬɶ ɨɛɪɚɛɨɬɚɧɧɨɣ ɩɨɫɥɟ ɮɪɟɡɟɪɨɜɚɧɢɹ
ɩɨɜɟɪɯɧɨɫɬɢ ɫɵɪɨɣ ɩɥɢɬɵ MDF.
,
MDF
.
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.
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Ʉɥɸɱɟɜɵɟ ɫɥɨɜɚ:
.
, MDF,
MDF
,
,
CNC,
,
[Davim, Clemente, Silva 2009].
.
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.
,
,
.
,
.
,
,
.
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,
.
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MDF.
201
CNC (BUSELLATO JET 130).
(DIMAR 107 055 9-HM Dynamic),
51 ɦɦ,
260 x 260 ɦɦ,
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,
1. Davim P., Clemente V. C., Silva S. 2009: Surface roughness aspects in milling MDF
(medium density fibreboard), The International Journal of Advanced Manufacturing
Technology 40
2. Iskra P., Tanaka C. 2005: The influence of wood fiber direction, feed rate, and cutting
width on sound intensity during routing, European Journal of Wood and Wood
Products 63
3. Orlicz T. 1988: Obróbka drewna narz dziami tn cymi. Wyd. SGGW
4. Staniszewska A., Zakrzewski W. 2002: Obróbka cieciem. Wyd. AR w Poznaniu
Streszczenie: Wpáyw podstawowych czynników na chropowatoĞü powierzchni po frezowaniu
páyty MDF. Celem pracy by o okre lenie wp ywu takich czynników jak posuw na z b, sposób
mocowania przedmiotu i w a ciwo ci materia u na chropowato powierzchni elementu po
frezowaniu p yty MDF. Proces obróbki by realizowany przy zastosowaniu trzech
warto ciach posuwu, odpowiednio 0,2, 0,4 i 0,6 mm. W eksperymencie wykorzystano
standardowy frez trzpieniowy dwuostrzowy o zu yciu VB=0,2 mm. Obróbka realizowana
by a z wykorzystaniem frezarskiego centrum obróbkowego CNC. Elementy na stole
obrabiarki mocowane by y na dwa sposoby: przy pomocy przyssawek podci nieniowych oraz
z zastosowaniem cisków mechanicznych. Analiza uzyskanych wyników pozwoli a
stwierdzi istotny wp yw sposobu mocowania przedmiotu oraz w a ciwo ci materia u na
chropowato powierzchni. Zaobserwowano równie wzrost warto ci parametrów Rz i Ra
wraz ze wzrostem posuwu na ostrze. Najlepsz jako powierzchni obrobionej stwierdzono
wi c w przypadku frezowania elementu wykonanego z p yty MDF2, zamocowanego na
przyssawkach przy zastosowaniu minimalnej warto ci posuwu.
Katarzyna Laszewicz, Jaros aw Górski,
Department of Mechanical Woodworking,
02-776 Warsaw, Poland,
Determination of Absolute Molar Mass Distribution of Paraloid B72
RADOMSKI ANDRZEJ, MA KOWSKI PIOTR, KO CIELNIAK AGNIESZKA
Department of Wood Science and Wood Protection, Warsaw University of Life Sciences – WULS (SGGW)
Abstract Determination of Absolute Molar Mass Distribution of Paraloid B72. In this molar mass distribution of
Paraloid B-72 was determined by size exclusion chromatography using polystyrene and poly(methyl
methacrylate) standards. The results were verified by determining intrinsic viscosity of Paraloid in
tetrahydrofuran. Smaller deviation of the results was found in the case of using the calibration based on
polystyrene. The calibration curve was successfully modified by numeric methods to obtain full consistence of
chromatography and viscometry results.
Keywords: Paraloid B72, molar mass distribution, size exclusion chromatography, universal calibration,
viscometry
INTRODUCTION
Wood is one of the most valuable materials used by man for thousands of years. Its
main drawback is the relatively low stability, resulting from the processes of destruction by
biological, chemical and physical agents. One way to improve the stability of wood,
especially partially destroyed, is the use of polymers consolidation (Ciabach 2001). There are
a lot of polymers fulfilling this role, but Paraloid B-72 is the wood consolidant the most often
used, due to its resistance and elasticity (glass transition temperature is 40°C) (Chapman &
Mason 2003). Paraloid B-72 is copolymer of ethyl methacrylate (EMA) and methyl acrylate
(MA). Ciabach (1998) stated its composition to be 30% of MA and 70% of EMA, while
Lazarri and Chiantore (2000) stated different composition of MA (32.0%), EMA (65.8%) and
addition of butyl methacrylate (BMA, 2.2 %). Polymerisation degree is about 900, although
individual samples have a bit different values (Melo et al. 1999, Chiantore et al. 2000, Lazarri
& Chiantore 2000).
Molar mass is an important parameter characterizing polymers, which can be
determined conveniently by size exclusion chromatography (SEC). The method gives
complete information on molar mass distribution. Unfortunately, the result of determination is
not absolute but dependent on the molar mass standards used. While direct standards for
Paraloid are non-available, standards of poly(methyl methacrylate) (PMMA) are commonly
used (Melo et al. 1999 Lazarri & Chiantore 2000). Paraloid as a copolymer with a
considerable fraction of acrylic esters may, however, show different hydrodynamic properties,
which may result in falsifying the analysis results. Neither Mark-Houwink universal
calibration can be applied to Paraloid because there are no Mark-Houwink coefficients
available in the literature.
In this paper, direct calibrations with PMMA and polystyrene (PS) standards were
applied, while viscometry was used in order to verify the results of the SEC.
206
A sample of Paraloid B-72 from Rohm & Haas was used for investigations, which
was designated as “unaged” one. Another sample, named “aged”, was investigated in parallel,
which was previously oven-heated at 110°C for 170 hours.
Molar mass distribution was analysed by Shimadzu LC-20AD chromatograph
equipped with degasser DGU-20A3, CTO-20A oven, LC-20AD pump and RID-10A
refractometer. The samples were injected by Rheodyne 7725i manual valve with the loop
20 l. Sample separation was conducted on Nucleogel M-10 column from Macherey-Nagel at
30°C. Tetrahydrofuran (THF, analytical grade, from ChemPur) was used as eluent at a flow
2cm3/min. Shimadzu LC Solution software was applied for data collection and apparatus
controlling. Chromatogram processing for molar mass analysis was performed using Polymer
Standard Service (PSS) software, PSS Calibrationprogram V2.99 and PSS WinGPC scientific
V2.74. Two sets of standards were used – polystyrene (Polymer Laboratories) of molar mass
range 6.85×106÷1.70×103 and PMMA (PSS) of molar mass range 9.81×105÷1.02×102.
Concentrations of standards solutions were 1.0g/dm3, except for samples with the highest
masses (M>106), for which the concentration was 0.5g/dm3.
Viscosity analyses were carried out on Ubelhode viscometer No. I, with ViscoClock
automatic measuring head (Schott Instruments GmbH). The measuring system was placed in
thermostat at 30°C. Polymers solutions in THF was made of concentrations c 5g/dm3 and
next series of solutions diluted at 1:1, 1:4, 1:8 and 1:12 ratio, respectively. Hagenbach
correction for kinetic energy (-) was calculated according to equation - = 9903·t–2, where t is
the time of flow through the capillary. On the basis of the results obtained, values of relative
viscosity ( rel) were calculated.
The results of viscosity measurements obtained for both samples are presented in the
Figure 1. Intrinsic viscosity values [ ] were determined from extrapolation of the expression
ln( rel)/c to zero concentration limit. Calculations were made using the spreadsheet MS Excel
and LINEST function (REGLINP in Polish language version) as points of intersection of
trend line with Y axis Y. In the case of Paraloid unaged, the result was [ ] =
(49.33±0.19)cm3/g, while for the sample aged [ ]* = (53.70±0.18)cm3/g. The calculated
uncertainties of measurement show good accuracy of the intrinsic viscosity determination.
207
aged
unaged
ln( Krel)/c /(cm3·g–1)
50
R2 = 0,9962
40
R 2 = 0,9928
30
0
2
4
concentration, c/(g/cm 3) ×103
6
Fig. 1 Determination of intrinsic viscosity for Paraloid B-72 in THF at 30°C
As a result of the aging of Paraloid sample increase of its solution viscosity is
observed, hence the molar mass also increases. This phenomenon proves the ongoing process
of combining molecules of Paraloid B-72 during thermal aging. Methacrylate polymers
undergoes usually depolymerisation on aging, while in the case of acrylic polymers an
increase in molar mass is common, especially during photolytic aging. Since Paraloid B-72 is
a copolymer of acrylate and methacrylate, dominance of one of these processes is difficult to
predict. Lazzari and Chiantore (1993) obtained at a higher temperature (150°C) results
indicating depolymerisation of Paraloid B-72. Parallel studies by the same authors on Paraloid
B-44, which is a copolymer of ethyl acrylate (30%) and methyl methacrylate (70%), carried
out at 135°C showed, in turn, increase in molar mass during aging, as in the studies presented
in this paper.
Next the values of the intrinsic viscosity of Paraloid B-72 were determined by size
exclusion chromatography. The calibration curves obtained from PS and PMMA standards
are presented in the Figure 2. Despite the apparently minor differences between the curves,
the results obtained differ very clearly (Table 1), largely because of different Mark-Houwink
coefficients. The values of the coefficients (K and ) for PS were taken from the software
database (PSS), and for PMMA were assumed after Chen et al. (1993).
Table 1 The results of intrinsic viscosity determination by SEC
standards
PS
PMMA
K /(cm3·g–1)
0.01363
0.00756
D
0.714
0.731
208
[K] (unaged)
46.51
27.90
[K]* (aged)
50.03
29.76
Fig. 1 Calibration curves for PS and PMMA on applied column
Determined intrinsic viscosities of Paraloid B-72 show that the values obtained by
polystyrene calibration are closer to the absolute results than those from poly(methyl
methacrylate) calibration. This means that the polystyrene molecule is more similar to
Paraloidu B-72 than PMMA, from the viewpoint of chain shape in solution. It it likely, that
coefficient, which refers to the chain rigidity, is closer to the values for PS. Polyacrylates have
a single substituent with every second carbon in the chain, in contrast to polymethacrylates,
which rigidity is increased by the presence of additional methyl group at the same carbon
atoms. Because of Paraloid B-72 is formed by copolymerisation, its chain segments of greater
rigidity (ethyl methacrylate) are separated by more elastic (methyl acrylate). As the result, the
whole chain is less stiff than PMMA, like a chain of polystyrene.
With actual values of the intrinsic viscosity for Paraloid B-72 an attempt to modify
SEC calibration curve was made in order to obtain agreement of chromatographic and
viscometric results. On the base of PS calibration, new K and coefficients were sought using
Solver function of MS Excell in a way that the following relationships were retained:
> @PS M PS > @B72 M B72
and
K PS M PS
PS 1
K B72 M B72
B72 1
.
While seeking the solution that meeting above requirements a series of matching
values were obtained, presented in Table 2. A detailed numerical analysis has shown that
further optimisation is not possible, as the solution is not a pair of values, but a set of points
forming a curve in coordinate system K and .
Table 2 Selected K and
K
0,653
0,03063
0,685
0,02114
coefficients of optimised range.
0,704
0,01714
0,726
0,01328
0,738
0,01156
0,751
0,01005
For further calculations, a pair of parameters was chosen, bold-assigned in Table 2,
guided by additional criteria. Mark-Houwink coefficients for acrylic homopolymers show
diversity. Buback et al. (1998) stated that for poly(methyl acrylate) K = 0.00195cm3/g and =
0.660, while Beuermann et al. (1998), estimated K = 0.00122cm3/g and = 0.700 for the
209
poly(butyl acrylate). Comparing these parameters with those for PMMA (Table 1) The
presence of methyl substituent in the chain as well as greater length of the alcohol in ester
group may be supposed to increase the value of coefficient. Since Paraloid B-72 is a
copolymer of methyl acrylate and ethyl methacrylate,
may be assumed about 0.7.
Considering the Table 2, the following parameters were taken for Mark-Houwink calibration:
3
B72 = 0.704 and KB72 = 0.01714cm /g. These values cannot be regarded as actual MarkHouwink parameters for Paraloid B-72, but as certain computational factors only, which can
be used to modify the calibration curve.
Application of the new calibration gave SEC results of [ ] = 49.66, and [ ]* = 53.38
cm3/g, which are consistent with viscometry with a deviation less than 0.7%. The full molar
mass distribution curves for Paraloid B-72, depending on the calibration applied, are shown in
Figure 3 and 4. There is a noticeable discrepancy between the curve obtained from PMMA
calibration and this calculated on the base of assumed KB72 and B72. On the other hand, molar
mass distribution based on polystyrene calibration is closer to the actual. This proves better
suitability of polystyrene standards of molar mass for Paraloid B-72 analysis then PMMA
standards, commonly used today.
Fig. 3 Molar mass distribution of unaged Paraloid B-72 depending on calibration applied
210
Fig. 4 Molar mass distribution of aged Paraloid B-72 depending on calibration applied
Earlier studies of other authors on Paraloid B-72, based on PMMA calibration,
showed that Mn = 41, Mw = 88, and polydispersity, D = 2.15 (Lazzari and Chiantore 1999) or
Mn = 44.8, Mw = 104.9 and D = 2.34 (Melo et al. 1999). In this paper, the results obtained by
calibration of PMMA are Mn = 51.17, Mw = 119.0 and D = 2.32. Lack of the results
repeatability is clearly visible, what maybe corresponds with product properties rather than
measurement inaccuracy. Thus, further studies seem to be valuable, especially on the
polystyrene standards application, which proves to be more useful than previously used
poly(methyl methacrylate).
CONCLUSIONS
The results of our investigations study allow the following conclusions:
o It is relatively easy to verify the results of the chromatographic determination of the
molar mass of polymers, including copolymers, like Paraloid B-72, using viscometry
as a second analytical method. The same measurement conditions, i.e. solvent and
temperature have to be ensured.
o SEC column calibration with polystyrene standards allows getting results of intrinsic
viscosity of Paraloid B-72 more consistent with viscometric measurements than the
commonly used calibration with poly(methyl methacrylate) standards.
o It is possible to modify numerically the calibration curve according to the results of
viscometry and thus obtain the actual molar mass distribution of Paraloid B-72.
o Thermal degradation of Paraloid B-72 at 110°C for 170 hours leads to its molar mass
increase, as macromolecules bonding processes predominate depolymerisation.
211
REFERENCES
1. BEUERMANN S., PAQUET JR. D.A., MCMINN J.H., HUTCHINSON R.A. 1996:
Determination of free-radical propagation rate coefficients of butyl, 2-ethylhexyl, and
dodecyl acrylates by pulsed-laser polymerization, Macromolecules, 29 (12), 4206-15
2. BUBACK M., KURZ C.H., SCHMALTZ C. 1998: Pressure dependence of propagation rate
coefficients in free-radical homopolymerizations of methyl acrylate and dodecyl acrylate,
Macromoecular Chemistry and Physics, 199 (8), 1721-7
3. CHAPMAN S., MASON D. 2003: The use of Paraloid B-72 as a surface consolidant for
stained glass, Journal of the American Institute for Conservation, 42 (2), 381-92
4. CHEN Y.-J., LI J., HADJICHRISTIDIS N., MAYS J.W. 1993: Mark-Houwink-Sakurada
coefficients for conventional poly(methyl methacrylate) in tetrahydrofuran, Polymer
Bulletin, 30, 575-8
5. CHIANTORE O., TROSSARELLI T., LAZZARI M. 2000: Photooxidative degradation of
acrylic and methacrylic polymers, Polymer, 41, 1657-68
6. CIABACH J. 1998: ywice i tworzywa sztuczne stosowane w konserwacji zabytków,
7. Wydawnictwo Naukowe Uniwersytetu Miko aja Kopernika, Toru
8. CIABACH J. 2001: W a ciwo ci ywic sztucznych stosowanych w konserwacji zabytków,
Wydawnictwo Naukowe Uniwersytetu Miko aja Kopernika, Toru
9. LAZZARI M., CHIANTORE O. 2000: Thermal-ageing of paraloid acrylic protective
polymers, Polymer, 41, 6447-55
10. MELO M.J., BRACCI S., CAMAITI M., CHIANTORE O., PIACENTI F. 1999:
Photodegradation of acrylic resins used in the conservation of stone, Polymer Degradation
and Stability, 66, 23-30
Streszczenie: Oznaczanie bezwzglĊdnego rozkáadu mas molowych Paraloidu B-72. W pracy
przeprowadzono oznaczenie rozk adu mas molowych Paraloidu B-72 metod chromatografii
wykluczania przestrzennego z zastosowaniem wzorców z polistyrenu i poli(metakrylanu
metylu). Zweryfikowano wyniki poprzez wyznaczenie warto ci granicznej liczby
lepko ciowej Paraloidu w tetrahydrofuranie. Stwierdzono mniejsze odchylenia wyników w
przypadku zastosowania kalibracji na bazie polistyrenu. Z sukcesem numerycznie
zmodyfikowano krzyw kalibracyjn , by uzyska pe n zgodno wyników chromatografii i
wiskozymetrii.
Warsaw University of Life Sciences – SGGW,
Non-degrading nitration of pinewood cellulose
RADOMSKI ANDRZEJ, ZAWADZKI JANUSZ, DRO D EK MICHA , SZADKOWSKI
JAN
Department of Wood Science and Wood Protection, Warsaw University of Life Sciences – WULS (SGGW)
Abstract: Non-degrading nitration of pinewood cellulose. In this work, pinewood cellulose nitration was
investigated, using a mixture of nitric and acetic acid with acetic anhydride. The process time and temperature
were changed. Reaction products were analysed for nitrogen number and molar mass. A significant influence of
temperature on degradation phenomenon of cellulose was confirmed. Low temperature of the reaction and time
of 5 hours favour obtaining nitrocellulose that show the highest polymerisation degree and nitrogen number
equal to 14.1%.
Keywords: cellulose, pinewood, nitration, molar mass
INTRODUCTION
One of most the important properties of cellulose, as macromolecular compound, is
degree of polymerisation or molar mass. For many years, scientists have been carrying out
research on effective methods for its determination. Some of known methods, such as
viscosity measurement in solutions of aqueous metal complexes, can cause degradation of
cellulose, especially oxidised one (Strli et al. 1998, Dupont & Mortha 2004). In other
methods the applicability of solvent may be limited to small molar mass cellulose, as in the
case of dimethylsulphoxide (DMSO). In turn, N,N-dimethyacetamide/LiCl system, used
lately in chromatography, requires laborious preparation of cellulose solutions, and long
procedure creates many possibilities for error (Bikova & Treimanis 2002, Dupont 2003, Strli
& Kolar 2003, Sundholm & Tahvanainen 2003).
In this situation, prior cellulose processing in order to obtain easy-soluble derivative
is still competitive. The possibility of non-degrading synthesis of derivatives is fundamental
condition of these methods. Their applicability to direct analysis of cellulose without its
isolation from wood is another interesting perspective. Derivatives that are the most
frequently used are nitrate or carbanilate (Heinze & Liebert 2001, Mormann & Michel 2002,
Fischer 2004). Cellulose nitrate (nitrocellulose, NC) is the best-described derivative of
cellulose from the viewpoint of synthesis and analytics (Urba ski 1967, 1983, Siochi & Ward
1989). It shows good solubility in tetrahydrofuran (THF), a universal solvent for size
exclusion chromatography (SEC). Since the esterification of cellulose molecule may involve
up to three hydroxyl groups per glucopyranose ring, nitration product may be nonhomogeneous. A complete nitration is therefore the best solution, which ensures the chemical
uniformity molecules. Of the many methods of cellulose nitration, only two allow such a full
substitution, without significant degradation of the product.
The first of them is based on the action of nitric and phosphoric acid, usually in the
presence of phosphoric anhydride. Since phosphoric acid do not cause nitrate hydrolysis, it is
possible to achieve a higher degree of esterification. Berl & Rueff (1930) applied the mixture
with P2O5 and obtained nitrocellulose of nitrogen content close to the maximum (about 14%).
213
In the case of P2O5 however, some difficulties in stirring may occur due to the tendency to
polyphosphoric acid gel formation, which is difficult to break up (Staudinger & Mohr 1937).
A mixture of nitric and acetic acid with acetic anhydride was used for the first time
already in 1908 (Whistler 1963). This mixture was applied to cellulose trinitrate synthesis for
molar mass determination. It allows to obtain the product of nitrogen number 14% or even
higher and gives nitrocellulose of higher viscosity than mixtures with phosphoric acid, what
indicates minimal degradation. The main disadvantages of this mixture are non-swelling of
organic material, short time of safe usage and the necessity of processing at low temperatures.
Bennett and Timell (1955), using a mixture of 43% HNO3, 32% CH3COOH and 25%
(CH3CO)2O, nitrated linters at 0°C and obtained a product containing 14.14% of nitrogen. For
3-4 hours nitration was not cause degradation, while further extension of reaction time
resulted in noticeable degradation of nitrocellulose.
Bleached Kraft pulp isolated from pinewood (Pinus sylvestris L.) was taken from the
Institute of Papermaking and Printing of Technical University of ód .
Fuming nitric acid, used for the nitration, was freshly obtained from a mixture of
concentrated nitric and sulphuric acids in 1:2 ratio by volume, by distillation under reduced
pressure, in order to avoid the temperature of the vapour to exceed 65±5°C.
Other reagents and solvents used were of analytically grade.
Nitration procedure:
Conical flask provided with a mechanical stirrer was placed in a proper bath – water,
ice or ice with salt. 29cm3 of glacial acetic acid was poured into the flask and then 29cm3 of
acetic anhydride was added while stirring. Successively, 27cm3 of fuming nitric acid was
added slowly, to ensure the temperature of the mixture would not rise more than 5°C. To a
nitrating mixture at a suitable temperature (–10±3, +2±2 and +12 ± 2°C) 4g of cellulose was
added slowly, still stirring. The rate of adding cellulose was adjusted so that the reaction
temperature increase did not exceed 5°C. After an appropriate period (2, 3 or 5 hours)
nitrocellulose was filtered on a Büchner funnel and washed with water until a neutral pH of
filtrate. At last, the samples were placed in round-bottomed flasks, poured with methanol and
boiled for 3-4 hours to stabilise the product.
Determination of nitrogen number of nitrocellulose:
Samples of about 4 grams of nitrocellulose were carefully grinded and vacuum dried
to constant mass at 50°C. About 0.5g of each NC was weighed to the nearest 0.2mg and
placed in conical flask. 50 cm3 of 95% H2SO4 was added and the mixture was closed and
placed on magnetic stirrer in order to dissolve NC prior to titration. The mixture was titrated
with a solution of Mohr's salt to change the colour from greenish-yellow to pink-yellow. The
measurements were repeated to obtain three consecutive results that differ by up to 0.05% N.
Titrant solution was obtained by dissolving 98g of Fe(NH4)2(SO4)2·6H2O (Mohr's salt) and
125cm3 of concentrated H2SO4 in a 500cm3 flask. Titrant concentration was determined by
titrating a sample of KNO3 (13.85% N), dried to constant weight, according to the above
procedure.
Size exclusion chromatography (SEC):
214
NC samples with masses of 0.050±0.005g were weighed and moved to closed
vessels. The vessels were poured with 10cm3 of tetrahydrofuran (THF) and placed in a rotator
for 6 hours. Solutions thus obtained were subjected to analysis, using Shimadzu LC-20AD
chromatograph, equipped with RID-10A refractometer. Separation was conducted on
Nucleogel M-10 column at 35°C, with eluent (THF) flow of 2cm3/min. The samples were
injected by Rheodyne 7725i manual valve with the loop 20 l. Shimadzu LC Solution
software was applied for data collection and apparatus controlling. Chromatogram processing
for molar mass analysis was performed using Polymer Standard Service (PSS) software, PSS
Calibrationprogram V2.99 and PSS WinGPC scientific V2.74. Polystyrene standards
(Polymer Laboratories) were used of molar mass range 6.85×106÷1.70×103. The values of
Mark-Houwink coefficients for PS were taken from the software database (PSS) as
K=0.01363 and =0.714, while for high-nitrogen NC they are: K=0,021 i =0,89 (Radomski
2004).
The results of nitrogen number analysis of nitrocellulose samples obtained, are
presented in the Figure 1. In the case of nitration at –10°C for 3 and 5 hours, a high degree of
cellulose esterification is yielded. Extension of time results in a small increase in nitrogen
content. The result obtained for the process carried out for 2 hours is not consistent with the
other results. Anticipating the next results it can be concluded that this sample was not
homogeneously nitrated. Improper stirring and short reaction time were insufficient for
complete nitration of the samples interior, in contrast to outer layers. For reaction carried out
for five hours we get the nitrogen number of 14.10%.
14,10
13,89
nitrogen number /%
14
13,97
13,43
13,17
13,53
13,38
13,28
2h
3h
5h
13
8,98!
12
–10
+2
+12
nitration temperature, t/°C
Fig. 1 Nitrogen numbers of nitrocelluloses obtained
In the case of the nitration process conducted in the temperature range 0÷4°C, there
is a clear relationship between the reaction time and nitrogen number of the product. The
longer the nitration, the higher nitrogen number is yielded. After 5 hours of nitration, the
result is close to 14%. In the case of nitration at the highest temperature, it was found that the
215
reaction seems to reach equilibrium, as the extension of time does not increase the degree of
substitution. The maximum nitrogen number is 13.53%. Further reaction causes a slight
decrease of its value, which may be due to decomposition of nitrating mixture at process
temperature.
Mn /kg·mol
–1
20
2h
3h
5h
15
10
–10
+2
12
Fig. 2 Numbers average molar mass of nitrocelluloses obtained
Pw
1600
2h
3h
5h
1200
800
–10
+2
+12
Fig. 3 Weight average polymerisation degree of nitrocelluloses obtained
The results of SEC determination of molar mass distribution were presented as
averages comparison, in the Figure 2 and 3. In the case of number average molar mass (Mn),
differences between individual samples seem to be random and no clear dependence can be
concluded. Weight average, presented as polymerisation degree (Pw), is more sensitive to
216
changes in the fraction of the largest molecules. When reactions were conducted at +2°C,
molecules size decrease with prolonged reaction time, which indicates some degradation
during the nitration. The first of the samples nitrated at –10°C is inappropriate for comparison
due to incomplete substitution. Similar polymerisation degree indicates, however, the
heterogeneity of the nitration. One part of cellulose sample was highly nitrated, while the
other one was only slightly nitrated, so it remained insoluble. The samples nitrated at –10°C
for 3 or 5 hours do not show evidence of degradation. Their polymerisation degree are higher
than for the samples obtained at +2 and +12°C. The last samples, obtained at +12°C, do not
show the downward trend in Pw with increasing time of nitration. However, due to much
lower nitrogen number of NC, the results cannot be treated with the same reliability as the
previous one, since the Mark-Houwink coefficients were optimised for highly nitrated
cellulose.
Another parameter that strongly affects the quality of nitration product is the reaction
temperature. The highest molar masses are obtained when nitration is conducted below zero
temperature. The increase in temperature causes a clear decrease in polymerisation degree of
NC, regardless of the time of the nitration. Comparison of the results shows clearly that
degradation of nitrated cellulose may occur, especially at temperatures above zero. NC
obtained at –10°C shows polymerisation degree above 1300, while nitrated at +12°C has it at
much lower level of about 1100. Such a difference is significant and it should be taken into
consideration when applying nitration to molar mass analysis of cellulose.
In addition, as there is no clear dependence of number average molar mass of NC on
nitration conditions, the process can be recognised as concerning mainly the largest
molecules. The longest chains fragmentation reduces significantly the weight averages and
has significantly lower influence on number averages.
CONCLUSIONS
A general conclusion for the application of the method presented is the necessity of
providing the optimal conditions of nitration, from the viewpoint both eliminating possible
degradation of NC and complete esterification of hydroxyl groups. Special care has to be paid
at the following questions:
o Low water content in nitrating mixture is critical. During the distillation of nitric acid,
a key concern is to maintain the lowest temperature of the process. This prevents the
decomposition of fuming nitric acid on the oxides of nitrogen, oxygen and water.
o Adequate stirring during nitration is very important to ensure, otherwise there may be
heterogeneous substitution of cellulose.
o Temperature of nitration plays a key role in the degradation of nitrocellulose. Nitrating
at –10°C ensures decrease in this phenomenon. Only weight average molar mass
shows significant dependence on temperature, which indicates the degradation to be
concerned with the largest molecules.
o When nitration is conducted at –10°C, a time of nitration should not be too short due
to possibility of incomplete nitration. As there is no significant risk of cellulose
degradation, reaction time should be extended to about 5 hours, which yield maximum
nitrogen number of nitrocellulose.
217
REFERENCES
1. BENNETT C. F., TIMELL T. E., 1955: Preparation of cellulose trinitrate. Svensk
Papperstidning 58, 281-6
2. BERL, E., RUEFF, G.,1930: Über die Nitrierung von Cellulose mit PhosphorsäureSalpetersäure-Mischsäuren (Vorläufige Mitteilung). Berichte der Deutschen
Chemischen Gesellschaft, B: Abhandlungen, 63(11), 3212
3. BIKOVA, T., TREIMANIS, A., 2002: Problems of the MMD analysis of cellulose
by SEC using DMA/LiCl: A review, Carbohydrate Polymers, 48, 23-28
4. DUPONT, A.-L., 2003: Cellulose in lithium chloride/N;N-dimethylacetamide,
optimisation of a dissolution method using paper substrates and stability of the
solutions. Polymer, 44, 4117-26
5. DUPONT, A.-L., MORTHA, G., 2004: Comparative evaluation of size-exclusion
chromatography and viscometry for the characterisation of cellulose. Journal of
Chromatography A, 1026, 129-41.
6. FISCHER, M., 2004: Polymeranaloge Carbanilierung von Cellulose. Dissertation,
der Fakultät Forst-, Geo- und Hydrowissenschaften der Technischen Universität
Dresden
7. HEINZE, T., LIEBERT, T., 2001: Unconventional methods in cellulose
functionalization. Progress in Polymer Science, 26, 1689-762
8. MORMANN, W., MICHEL, U., 2002: Improved synthesis of cellulose carbamates
without by-products. Carbohydrate Polymers, 50, 201-8
9. RADOMSKI A., 2004: Zastosowanie chromatografii SEC i HPLC do analizy
polimerowych materia ów energetycznych i ich mieszanin, Dissertation, Faculty of
Chemistry, Warsaw University of Technology, Warsaw
10. SIOCHI, E.J., WARD, T.C., 1989: Absolute molecular weight distribution of
nitrocellulose. Journal of Macromolecular Science, Reviews in Macromolecular
Chemistry and Physics, C29(4), 561-657
11. STAUDINGER, H., MOHR, R., 1937: Über hochpolymere Verbindungen, 179.
Mitteil.: Über die Konstitution der Cellulose-nitrate. Berichte der Deutschen
Chemischen Gesellschaft, B: Abhandlungen, 70(11), 2296-309
12. STRLI , M., KOLAR, J., 2003: Size exclusion chromatography of cellulose in
LiCl/N,N-dimethylacetamide. Journal of Biochemical and Biophysical Methods, 56,
265-79
13. STRLI , M., KOLAR, J., ŽIGON, M., PIHLAR, B., 1998: Evaluation of sizeexclusion chromatography and viscometry for the determination of molecular
masses of oxidised cellulose. Journal of Chromatography A, 805, 93-99
14. SUNDHOLM, F., TAHVANAINEN, M., 2003: Preparation of cellulose samples for
size-exclusion chromatography analyses in studies of paper degradation. Journal of
Chromatography A, 1008, 129-34
15. URBA SKI, T., 1967: Chemistry and Technology of Explosives, Vol.3, Pergamon
Press, Oxford
16. URBA SKI, T., 1983: Chemistry and Technology of Explosives, Vol.4, Pergamon
Press, Oxford
17. WHISTLER, R., 1963: Methods in carbohydrate chemistry. Vol.3, Cellulose
Academic Press, New York, London
218
Streszczenie: Niedegradująca nitracja celulozy z drewna sosny. W pracy badano proces
nitrowania celulozy z drewna sosny mieszanin kwasu azotowego, octowego i bezwodnika
octowego. Zmieniano czas i temperatur procesu. Produkty reakcji by y analizowane pod
k tem liczby azotowej oraz masy molowej. Stwierdzono istotny wp yw temperatury na proces
degradacji celulozy podczas nitrowania. Niska temperatura i czas procesu 5h sprzyjaj
otrzymaniu nitrocelulozy o najwy szym stopniu polimeryzacji oraz liczbie azotowej
wynosz cej 14,1%.
Characteristic values of quality for spruce timber determined by MTG
Timber Grader device
ALENA ROHANOVÁ
Faculty of Wood Sciences and Technology, Technical University in Zvolen
Abstract Characteristic values of quality for spruce timber determined by device MTG Timber Grader. This
contribution concerns the evaluation of spruce timber quality using the acoustic vibration method. The principle
of this grading method is applied in the device MTG Timber Grader. MTG Timber Grader measures dynamic
modulus of elasticity (MOE) and it determines the strength class C. Within the experiments, the various
parameters of quality were evaluated on timber of different lengths (long – 5 000 mm, short – 2 300 mm), such
as: wood density, dynamic modulus of elasticity and strength class C. The grading methods were in accordance
with European Standards.
The acoustic vibration method provides simple and fast measurement and evaluation of wood quality. However
the results show the suitability of using the acoustic method for timber grading in accordance to European
Standards also in condition of Slovakia, there is a need for more extensive analyses of timber quality evaluation
in both theoretical and application field.
Keywords: spruce wood, timber quality, vibration method, dynamic modulus of elasticity, strength class
INTRODUCTION
Wood and the assortement of some species are characteristic by its very good acoustic
properties.
The sound is transmetted only trough a material medium (solid, liquid or gas). People are
capable to perceive the sound waves with frequency range from 16 to 20 000 Hz. The sound
waves propagate with velocity that depends on its frequency and wave length as follows:
c = O · f [m.s-1],
where c - velocity of wave propagation [m.s-1],
O - wave length [mm],
f - frequency [Hz].
The velocity of sound wave propagation in wood can be calculated as follows:
c
E
[m s 1 ]
U
where E - Young´s modulus of elasticity [MPa],
U - wood density [kg.m-3].
These elastic properties of wood, such as modulus of elasticity and velocity of sound
propagation in wood can be determined on the basis of vibrations provoked by proper force
action. Amplitude of vibration depends on the frequency of applied force. The frequencies of
certain wave length reacts in wood with the maximal amplitude of vibration and these
frequencies are called resonant or own (natural) frequencies of wood.
Acoustic properties of wood are used as nondestructive methods for wood quality
assessment. The vibration method is applied in MTG Timber Grader device.
220
Timber Grader MTG - principle
Timber Grader MTG (Figure1) is patented manual portable device for nondestructive
method of measuring the strength classes and the modulus of elasticity.
It works on the principle of sound waves emission and the following observation of
natural frequency of wood. The obtained values are evaluated in software. It allows to
perform measurements in timber of softwood and hardwood species.
Input data:
- specification of wood species (in accordance with EN 14081- 4),
- moisture content of specimen [%],
- dimensions of specimen [mm],
- weight of specimen [kg].
Output values from the measurement are:
modulus of elasticity of wood MOE,
strength class C in accordance with EN 338. It determines 3 classes C18, C24 and
C30.
Figure 1. MTG Timber Grader - application
Samples used for the experimental testing were of structural dimensions (hereinafter
timber) prepared from spruce wood (Picea abies L.). Preparation of experimental material
consisted of:
I.
testing of timber (long): 40x190-5 000 mm - 52 pcs.,
II.
testing of timber (short): 40x120-2 360 mm - 52 pcs.
To determine the density of wood, three small specimen were sawn from each piece of long
timber (from the end parts and from the middle part of length).
The registration sheet was assign to each sample, containing:
¾ number and dimensions of sample,
¾ moisture content and density of wood (determined by gravimetric method),
¾ wood quality determined by acoustic vibration method (MOE, C class).
221
RESULTS AND THEIR ANALYSIS
The evaluation of statistical characteristics of experiments is summarised in table 1.
The density of wood obtained from small specimens was corrected to standard density ȡ12 and
it was applied for the evaluation of dependencies for both long and short sawn timber. The
dependency of wood density from modulus of elasticity is illustrated in Figure 2. It is
accompained by the dependency listed in EN 338, which shows lower values of modulus of
elasticity with the same values of density measured by the MTG Timber Grader device. Both
dependencies show high coefficient of correlation (long: rL = 0,75, short: rS = 0,82). The
results also show the insignicicant influence of sawn timber length on quality parameter
MOE. The analysis of parameter „strength class C is reduced only to three levels. Application
of three classes (C18, C24 and C30) cause the undercutting of strength values mainly for the
sawn timber with higher values of MOE (Figure 3). The results prove the need of strength
classes „C“ redifinition especially for higher values of MOE.
Table 1. Basic mathematic-statistical characteristics of wood density at w = 12%, vibration
method (w - wood moisture, MOE - dynamic modulus of elasticity)
Type of timber
Wood density
ȡ12
[kg.m-3]
(small
specimens)
Samples
-timberBasic mathematicstatistical
characteristics
n
MTG
Timber
Grader
_
x
xmin
xmax
V [%]
Short timber
40/120-2360 mm
Long timber
40/120-5000 mm
52
413
w
[%]
52
15,3
MOE
[MPa]
52
11303
w
[%]
52
16,25
MOE
[MPa]
52
11625
347
494
8,2
11,7
18,3
7,82
8047
15584
16
13,7
19,3
6,64
8233
16036
15,13
Modulus of elasticity MOEMTG,long,
and E0,mean [MPa]
MOEMTG,short
18000
M OE MTG ,long = -4425, + 38,876 * U 1 2
16000
r = 0,75
M O( MTG ,long, U 1 2 - vibration
M OE MTG ,s hort , U 1 2 - vibration
an
E 0 ,me a n, U me a n - E N 338
14000
12000
E 0 ,m
ea
,
04
-79
=
n
*
22
3,7
+4
U me
10000
8000
MO EMTG , s hort = - 6808, + 43,868 * U 1 2
r = 0,82
6000
320
340
360
380
400
420
440
460
480
500
520
540
560
W ood density U 12 an d U mean [kg.m -3]
Fig.2 Modulus of elasticity, MOEMTG,long, MOEMTG,short and E0,mean related to measured density
ȡ12 and ȡmean
222
55
Strength classes CMTG,short, CMTG,long and
characteristics strength fm,k [MPa]
50
45
MO( MTG,long, CMTG,long - vibration
MOEMTG,short, CMTG,short - vibration
E0,mean, fm,k - EN 338
40
35
30
f m,
25
k
=
8
-1
5
,6
+
1
04
,0
5
0,
*E
g
, l on
C MTG
m
ea
n
TG
+
715
, 57
=0
8
0,8
r=
O EM
*M
202
, 00
,l o n
g
20
CMTG,short = -1,962 + ,00218 * MOEMTG,short
15
10
6000
r = 0,90
8000
10000
12000
14000
16000
18000
Modulus of elas tici ty MOEM TG,short, MOEM TG,long and E0, me an
[M Pa]
Fig. 3. Change of strength class dependent from modulus of elasticity of spruce wood determined on
timber (short, long) using MTG Timber Grader device and compared to EN 338- fm,k.
CONCLUSION
The requirement of wood quality assesment based on various principles is justified and
still actual. It has its important share in static, structural and economic assesment of wood for
building construction.
Within the experiments, the quality of wood (MOE, C class, density of wood) was determined
on spruce sawn timber (long, short) and the experimental results were compared to values listed in EN
338. The results show the insignificant influence of timber length on quality parameter MOE.
Determination of strength classes „C“ using the MTG Timber Grader device undervalues the
characteristic strength for higher values of modulus of elasticity MOE. The results proved the
need of redifinition of number of strength classes „C“ espacially for higher values of MOE.
This study was supported by project under the contract No.VEGA 1/0549/08 „Quality
of wood for building structures and its experimental analysis and verification in situ”.
REFERENCES
1. ROHANOVÁ, A.- JABLONSKI, M. - KRSOSEK, S. (2009): Strength grading of
constructional lumber in regard to European, German, Slovak and Polish standards. In
Annals of Warsaw University of Life Sciences. Forestry and Wood Technology. Warszawa : Warszaw University of Life Sciences Press, 2009. - ISSN 1898-5912. No. 69 (2009), p. 227-233.
2. EN 338 Structural timber Strength classes. 2004..
3. EN 14081- 4 Timber structures - Strength graded structural timber with rectangular
cross. section - Part 4: Machine grading - Grading machine settings for machine
controlled systems. 2009.
223
Streszczenie: JakoĞü tarcicy Ğwierkowej mierzona urządzeniem MTG Timber Grader. Praca
dotyczy wyznaczania jako ci tarcicy wierkowej metod wibroakustyczn . Metoda ta jest
stosowana w urz dzeniu MTG Timber Grader. Urz dzenie to mierz dynamiczny
modu spr ysto ci (MOE) oraz wyznacza klas jako ci C. W ramach eksperymentu mierzono
ró ne parametry jako ciowe w tarcicy o róznych d ugo ciach (deje potrzeba bardziej
szczegó owej analizy tarcicy zarówno w aspektach teoretycznych jak i zastosowania
praktycznego.
Doc. Ing. Alena Rohanová, PhD.,
Department of Furniture and Wood Products
Faculty of Wood Sciences and Technology,
Technical University Zvolen
T.G. Masaryka 24, 960 53 Zvolen
[email protected]
Logs and sawn Timber Quality for building constructions
ALENA ROHANOVÁ - ERIKA NUNEZ
Abstract Logs and sawn Timber Quality for structural timber. Timber used for building constructions is
generally made of softwood logs of III.A and III.B qualitative grade (class). The most important grading features
when screening the logs are: reaction wood, sap stain and rot (decay). The qualitative grade S0, SI or SII is
carried out by both visual and machine grading methods. Dominant grading parameters are knots. The machine
grading methods based on various principles (bending, acoustic, radiation...) offer more reliable results.
In the log processing for timber, the timber quality was evaluated by visual method according with STN 49
1531. The choice of timber in relation to log quality was taken into account. The results showed a higher
representation of the highest quality grade S0 for III.A (58%), for III.B only 25%. Therefore, the requirement of
the purpose-oriented assessment of timber quality directly at log processing is justified and economical.
Keywords: log, sawn timber, quality, knot, grading, visual method, structural timber
INTRODUCTION
For timber building constructions, we use the softwood timber made of logs of quality
grade III.A, III.B and III.C. The log quality is determined by visual method according with
the standard STN 48 0055, on the basis of the presence of wood defects, such as knots (the
most important), rot (decay), sap stain and reaction wood.
The requirements for quality of timber assigned for building constructions are specified in
the EN and Slovak Technical Standards (STN). The quality of wood is defined by the
parameters such as strength (stiffness), elasticity and density. The visual and machine grading
methods working on various principles (bending, vibration, ultrasonic and radiation) are used
to determine these parameters.
The principle of purpose-oriented log processing and sorting the wood into construction
timber is not utilized in practise in the conditions of Slovakia. This article (contribution)
analyses the grading process of logs and timber in compliance with Slovak Technical
Standards (STN).
Visual grading method was applied for the quality assessment of both logs and timber for
construction purposes, on the levels:
- log - quality of log - III.A, III.B, and III.C,
- timber - quality of timber - S0, SI and SII.
TIMBER QUALITY - visual method
In Slovakia, the quality of timber for building constructions is assessed by visual method
in accordance with STN 49 1531. It assigns the permitted range of wood defects such
as knots, cracks (splits). For construction timber, it assigns the following classes of quality:
S0 – high strength timber,
SI – normal strength timber,
SII – low strength timber.
The most important indicator of timber quality is its strength. Using the visual grading
method, it is not possible to determine precisely the strength of timber, but on the basis of
wood defects presence, we can predict the weakest (the most critical) portion of timber. Knots
are the most important grading parameter allowing to determine the quality class (grade).
225
2 methods are used for knots assessment:
x method of proportional knot dimensions (ratio of the sum of knot sizes across the
surface and the edge to double width of the sawn timber),
x method of knot area ratio – KAR method: cross – sectional proportion of the knots
(ratio of cross - sectional surfaces of all knots to cross – section of the total board
surface).
The spruce wood (Picea abies) was used for the experiments. Trial material was
obtained from logs. The quality of logs was determined by visual method in compliance with
STN 48 0055 in saw mill factory. The choice of logs was purpose-oriented: 6 pieces of logs of
III.A qualitative class and 7 pieces of logs of III.B qualitative class. The quality class III.C
was not present. Firstly, using the frame saw, one middle prism was obtained from each log.
Secondly, 4 planks of 50x190x5000 mm were obtained by following sawing of prism - 2 side
and 2 middle planks. Planks from each log were marked as follows: side: planks 1 and 4,
middle: planks 2 and 3 (Figure 1). The location of plank in prism was not taken into account
during the experiments.
Measuring was made on 52 pieces of planks, therefrom:
- 24 pcs. of qualitative class III.A,
- 28 pcs. of qualitative class III.B.
Fig.1 Transverse section across log – parts of cutting (prism, side sawn timber) and marking
of planks in prism.
Then, the thickness and the wide of planks were corrected into dimensions of 40x180x5000
mm. The quality of planks was evaluated by visual method in compliance with STN 49 1531.
The presence of pith was determined and the presence of knots was evaluated on all four sides
of plank (timber) by first (1.) method of their assesment (method of proportional knot
dimensions). Wood defects that significantly influenced the qualitative class of timber S0, SI
or SII, they were grafically noted into the registration sheet.
Results of visual grading of planks into the class S0, SI or SII are summarised in Table 1.
226
Table 1. Visual classes of planks S0, SI and SII from logs of quality III.A and III.B
planks - visual classes
logs
number
pcs.
pcs.
S0
SI
SII
III.A
6
24
4
14
6
III.B
7
28
1
7
20
Results of visual grading of logs and planks are shown in fig. 2. From the log quality III.A,
there was following representation of the qualitative classes of planks: S0 -17%, SI-58%
and SII-25%. For log quality III.B the percentage of qualitative classes of planks was: S03,6%, SI-25% and SII-71%.
Figure 2 Visual grading of logs (III.A and III.B) and planks SII, SI and S0
When comparing the qualitative classes of logs – planks it is possible to state the following
findings:
- from logs of III.A quality, the plank quality SI has the highest representation – 58% and the
lowest representation of plank qualitative class goes for S0 – 17%. Therefore, the quality of
certain logs was not sufficiently objectively determined,
- log quality III.B – qualitative classes S0, SI, SII have increasing tendency (4 – 25 – 71 %)
and therefore we can conclude the proper qualitatif classification of logs,
- from each of logs III.A1, III.A5 and III.A6, 4 planks were obtained (12 pcs.). Therefrom 2
planks from each set (in general middle position) were classified into the lowest qualitative
class SII. This can be explained by higher representation of planks of qualitative class SII
(25%) than the representation of qualitative class S0 for logs III.A.
Logs: 50% of III.A quality was not properly classified. This error could be caused by internal
cracks or rot that is not possible to detect from transverse section of log. The evaluation of
227
plank classification by visual grading method from III.B log quality revealed that the
qualitative classes of logs were determined objectively.
The results showed (refered to) the deficiency of objectivity and accuracy of qualitative
assesment of III.A logs (rot, cracks). However the qualitative class of logs III.B was
determined in compliance with the standard, the planks of SII qualitative class were
represented by the highest percentage – 71%. It shows the fact, that the suitability of using the
logs III.B for obtaining the timber for loadbearing constructions is overvalued.
CONCLUSION
The reliability of wooden construction members is conditioned also by the qualitative
choice of timber. The effective assesment is a result of purpose – oriented classification of
wooden raw material in processing chain from logs to sawn timber for building constructions.
The visual grading method is used for qualitative assesment of logs and timber. The logs of
quality class III.A offer the guarantee that the wood for loadbearing construction members
meet the proper quality. It can be proved by the highest representation of timber with normal
(standard) strength SI – 58%. The qualitative class of logs III.B was determined in
compliance with the standard, but the planks of the lowest qualitative class SII were
represented by the highest percentage – 71%. The results show the fact of overvaluation of the
suitability of using the logs III.B for construction timber for loadbearing constructions.
This study was supported by project under the contract No.VEGA 1/0549/08 „Quality
of wood for building structures and its experimental analysis and verification in situ”.
REFERENCES
1. STN 48 0055. 2007: Kvalitatívne triedenie ihli natej gu atiny.
2. STN 49 1531. 2001: Drevo na stavebné konštrukcie. as 1: Vizuálne triedenie pod a
pevnosti.
3. NUNEZ, E. (2010) Hodnotenie kvality dreva na stavebné konštrukcie vizuálnou
a ultrazvukovou metódou. Diplomová práca. Drevárska fakulta TU Zvolen, 2010, 87
s.
Streszczenie:
JakoĞü drewna okrągáego i materiaáów tartych w zastosowaniach
konstrukcyjnych. Tarcica w zastosowaniach konstrukcyjnych pochodzi zazwyczaj z k ód
iglastych w klasach III.A oraz III.B. Najwa niejszymi czynnikami przy sortowaniu k ód s :
drewno reakcyjne, prze ywiczenia oraz zgnilizna. Klasy jako ciowe S0, SI oraz SII s
nadawane przy sortowaniu wizualnym oraz maszynowm. Najwa niejszym czynnikiem w
procesie sortowania wizualnego s s ki. Sortowanie maszynowe bazuj c na wielu zasadach
(zginanie, promieniowanie, inspekcja akustyczna) oferuje bardziej wiarygodne wyniiki. W
trakcie sortowania tarcicy stosowano metod wizualn zgodnie z norm STN 49 1531.
Badano zale no ci mi dzy jako ci k ód a tarcicy. Wykazano wi ksz zawarto klasy S0 w
III.A (58%), dla III.B tylko 25%. Konieczno sortowania przeznaczeniowego ju przy
obróbce k ód jest uzasadniona oraz ekonomiczna.
Doc. Ing. Alena Rohanová, PhD.
Ing. Erika Nunez
Technická univerzita vo Zvolene, Drevárska fakulta
T. G. Masaryka 24, 960 53 Zvolen,
[email protected]
[email protected]
Static and dynamic modulus of spruce structural timber
ALENA ROHANOVÁ - RASTISLAV LAGA A - VLADIMÍR VACEK
Abstract: Static and dynamic modulus of spruce structural timber. A comparative study of static and dynamic
modulus of spruce structural timber has been performed. 52 structural timber samples were cut from 13 different
logs of the same forest stand. Static modulus of each board was obtained from bending test according to EN 408.
Dynamic modulus was calculated from board density and measured wave propagation velocity in timber using
Sylvatest Duo and MTG Timber Grader devices with build-in structural timber grading standards. Mean MOE
from static test according to EN 384 and mean MOE given by Sylvates Duo and MTG Timber Grader were
compared. Differences between MTG Timber Grader readings and static MOE were statistically non-significant.
Results showed that Sylvatest Duo overestimates MOE and that a correction is required, which takes into
account sample density and results of static bending tests.
Keywords: spruce wood, moisture wood , density, static modulus of elasticity, dynamic modulus of
elasticity
INTRODUCTION
Wood is a strategic row material. In majority buildings, it is an inevitable part of
constructions. Grading of wood is significant area of wood utilization. Two general methods
are used for determination of strength and stiffness properties of wood: visual grading and
machine grading. The visual method takes distribution of wood defects on the surface for
determination of strength quality. Knots are the main sorting criterion. The method does not
take into account wood density, which is significant parameter of wood quality. The machine
grading is based on bending principle or other principles such as ultrasound, vibration,
radiation, or combination of several indicating properties (Weidenhiller & Denzler 2009)
related to stiffness or strength. The most reliable is bending method however, it requires
sophisticated technologies.
The recent trend in machine grading focuses on acoustic principles (ultrasound, vibration).
The important feature of acoustic method is sound velocity „c“. It can be related to grading
characteristics:
c
E
U
[m s 1 ]
(1)
where E is dynamic modulus [MPa] and ȡ is wood density [kg.m-3].
Grading device MTG Timber Grader uses vibration principles, Sylvatest Duo device
uses ultrasound. Reliability of devices can be found while comparing their results with a static
bending test according to EN 408.
MTG Timber Grader
MTG Timber Grader is hand-operated device for grading structural timber. It grades
based on measured natural frequency of wooden board. Besides that it requires wood species,
moisture content (MC), board dimensions and weight. This device provides MOE at 12% of
MC, strength classes according to EN 338 at levels of C18, C24 and C30.
Sylvatest Duo
This portable device can sort boards, trunks or in situ construction elements. Based on
time of ultrasound wave propagation between probes and distance between probes it is able to
229
give MOE, MOR and C class. Sylvatest Duo also allows calculating the dynamic modulus
ES,dyn using the equation (1). This can be a useful tool for recalibration of given species from
a different location or unknown species when compared with static bending test results.
Bending method
It is performed according to EN 408 and two other standards are taken into account
EN 384, EN 338. Results of the method are modulus of elasticity MOE and bending strength
MOR at 12% of MC.
For testing we used construction size samples (boards) of spruce wood (Picea abies).
Dimension of these boars are 40x120x2200 mm3. 52 dried boards were placed into
conditioned chamber for reaching equilibrium moisture content w = 12% (RH = 65 %, t
=20oC) according to EN 384. MC and clear sample density were determined for each board.
MOE was evaluated using three mentioned methods: bending, ultrasound (Sylvatest Duo),
vibration (MTG Timber Grader).
The basic statistic is shown in the Table 1. From the results one can see the final.
Table 1: Descriptive statistic of clear specimen density and basic outputs of bending, ultrasound and
vibration methods. MOEB - static bending test, MOES - Sylvatest Duo (dynamic modulus -eq.1),
MOES,corr - Sylvatest Duo corrected, MOEM - MTG Timber Grader
Basic mathematic-statistical
characteristics
Density
ȡ12
Bending
MOEB
Ultrasound
Vibration
MOES
MOES,corr.
MOEM
[kg.m-3]
Number of samples
52
52
52
52
52
Arithmetic mean
413
11 518
13842
Maximum value
494
17318
16703
11518
15532
11303
15584
Minimum value
347
7107
10833
8405
8047
8
18
11
15
16
Coefficient of variation [%]
Paired t test showed that there were big differences between MOES and MOEB from bending
test. Differences between other were non significant on significance level of D = 0,01 (Table
2, Figure 1). It is obvious that the MOES,corr and MOEB are absolutely equal due to direct
derivation of MOES,corr. MTG device very well matched the static bending test.
Table 2. Results of paired t-test, probability that compared paired groups are equal
MOEB
MOES
MOES,corr.
MOES
0.0000
x
x
MOES,corr.
1.0000
0.0000
x
230
MOEM
0.0645
0.0000
0.0137
Mean
Mean±SE
Mean±1 ,96*SE
14000
13000
12000
11000
MOEs
MOEb
MOEm
10000
MOEs,corr.
Modulus of Elasticity MOE [MPa]
15000
Figure 1. Comparison of MOE’s between the methods
These MOE’s results compared to the density according to standard EN 338 tell us something
about reliability of measurements. One can see that MOE from Sylvatest Duo device without
taking into account a sample density is off the real result. Similar result was obtained on
different set of samples (Rohanova et al. 2010). Readjustment of this device based on a static
bending result is required (see MOES,corr).
Some boards of lower density cross over the standard line according to EN 338 and therefore
should be degraded to lower strength classes because of the density (Figure 3).
Modulus of Elasticity MOE, Emean [MPa]
18000
16000
14000
12000
MOES,corr.
MOES
MOEM
MOEB
EN 338
10000
8000
6000
340
360
380
400
420
440
460
480
500
520
540
560
Wood density U 12 and U mean [kg.m-3 ]
Figure 3 Density - MOE relations between methods and comparison to EN 338.
CONCLUSION
Mean MOE from static test according to EN 384 and mean MOE given by Sylvates
Duo and MTG Timber Grader were compared. Differences between MTG Timber Grader
readings and static bending MOE were statistically non-significant. Therefore, MTG is more
reliable device for measuring MOE when comparing to static bending test results. Sylvatest–
Duo device overestimates MOE and a correction is required, which takes into account sample
density and results of static tests according to EN 408.
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This study was supported by projects under the contract No.VEGA 1/0549/08 and
VEGA 1/0565/10.
REFERENCES
1. EN 338 Structural timber Strength classes. 2010.
2. EN 384 Structural timber. Determination of characteristic of mechanical properties
and density. 2004.
3. EN 408 Timber structures - Structural timber and glued laminated timber Determination of some physical and mechanical properties. 2003.
4. ROHANOVÁ, A. - LAGA A, R. - DUBOVSKÝ, J. (2010): Grading characteristics of
structural Slovak spruce timber determined by ultrasonic and bending methods.
http://www.cte.napier.ac.uk/e53/47.pdf. In The future of quality control for wood &
wood products, COST Action E53 : 4-7th May 2010, Edinburgh, UK. - Edinburgh :
Edinburgh Napier University, 2010. p. 9.
5. WEIDENHILLER A. - DENZLER, J. K. (2009) “Optimising machine strength grading
with three indicating properties”. In: Proceedings of the Economic and technical
aspects of quality control for wood and wood products. Cost Action E53 Conference
22nd – 23rd October 2009, Lisbon, Portugal. Paper No.7
Streszczenie: Statyczny i dynamiczny moduá sprĊĪystoĞci Ğwierkowej tarcicy konstrukcyjnej.
Przeprowadzono studium porównawcze statycznego i dynamicznego modu u spr ysto ci
tarcicy wierkowej. Wyci to 52 próbki z 13 ró nych k ód z tego samego rodowiska.
Statyczny modu wyznaczono poprzez zginanie zgodnie z norm EN 408. Dynamiczny
modu spr ysto ci by wyznaczony z g sto ci tarcicy i pr dko ci rozchodzenia si fal przy
u yciu urz dze Sylvatest Duo oraz MTG Timber Grader. rednie warto ci statycznego
modu u wyznaczonego z normy EN 384 oraz dynamicznego modu u otrzymanego z
Sylvatest Duo i MTG Timber Grader zosta y porównane. Ró nice pomi dzy wynikami z
MTG Timber Grader oraz otrzymanymi statycznie nie by y istotne statystycznie. Wyniki
wskazuj e Sylvatest Duo zawy a warto ci modu u spr ysto ci i wymaga korekcji.
Doc. Ing. Alena Rohanová, PhD., Ing. Rastislav Laga a, PhD., Ing. Vladimír Vacek
Faculty of Wood Sciences and Technology
Technical University in Zvolen
T.G. Masaryka 24, 960 53 Zvolen
[email protected]
[email protected]
[email protected]
Problems of the quality of wood machining by milling stressing the effect of
parameters of machining on the kind of wood
MIROSLAV ROUSEK, ZDEN K KOPECKÝ, MICHAL SVATOŠ
Faculty of Forestry and Wood Technology, Mendel University in Brno, Czech Republic
Abstract: Problems of the quality of wood machining by milling stressing the effect of parameters of machining
on the kind of wood. The paper deals with the method of measuring the roughness of surfaces originating after
milling. Effects of parameters of machining on kinds of wood were also studied. Results are demonstrated of
measuring the roughness of surface of wooden samples of eight broadleaved species (ring-porous and diffuseporous wood) and a conifer using a topographic method Talysurf. Evaluation of the experiment at selected
species was carried out by means of parameters obtained using 2D and 3D photography. The actual evaluation
of the surface quality was implemented by the Talysurf CLI 1000 apparatus. At the conclusion, an evaluation
was carried out using the 2D and 3D surface measurement.
Keywords: roughness, modelling, milling, wood, topographic method
INTRODUCTION
Milling is a technological process serving for the creation of the surface of certain
shape, dimensions and quality cutting material particles (chips) or wood fibre bundles (cutting
operation). Fig. 1 demonstrates the kinematics of cutting a chip at standard milling
(conventional milling). In practice, however, the actual chip cross-section can differ from the
nominal cross-section due to blunting, inaccurate spindle run, deviations of cutting edges
from the cutting circle, irregularities of the feeding device cycle and, particularly, due to
splitting off and heterogeneity of the workpiece material.
Fig. 1. Standard milling
The workpiece edge trajectory creates a cycloid curve, cutting speed being, however,
very high at higher diameters of milling tools in proportion to the feed rate. Thus, at the
section of the edge cut, it is possible to suppose with sufficient probability that its cutting
track creates a circle.
233
Problems of milling and the machining surface quality were already several times
examined being well processed at present. The paper is based on findings of authors and their
publications (LISI AN, 1996), (PROKEŠ, 1965), (SVOBODA E. et al., 2009) and a number
of other foreign and Czech authors.
The process of the chip creation shows a fundamental effect on the workpiece surface
quality and amply good him describing citation relations.
Feed per tooth:
v f 1000
(1)
fz
n z
z … number of edges of a milling head (milling cutter)
vf … feed speed of a workpiece [m.min-1]
Considering the milling cutter edge creates a circle it is possible to determine the
theoretical depth of the surface roughness (y) of milled surfaces up to hundredths of mm.
Then, we can accept a known relationship to determine the wave theoretical depth y:
y
f z2
fz
4 D
4 D y [mm]
(2)
y…..depth of the surface kinematical roughness [mm],
D….the cutting edge diameter of a milling head [mm],
fz …feed per the milling head edge
The relation (2) applies to absolutely accurate setting the milling head knives. In
practice, it is rather often difficult to set up milling heads into a cutting edge with absolute
accuracy. Thus, a situation demonstrated in Fig. 2 can occur.
fz
fz
Fig. 2. The workpiece surface at the inaccurate setting the knives
Characteristic factors determining the surface quality of a milled workpiece are as
follows: tree species, volume weight, mechanical properties, moisture content, and orientation
of wood fibres with respect to the direction of the cutting edge movement. For the purpose of
the paper it is sufficient when these factors are expressed by the tree species and its moisture
content. The optimum moisture of wood is 8 ± 2%.
Kinetic roughness originates due to mutual motions of a milling head and a workpiece.
Owing to the rotational motion of a milling cutter and usually the straight-line shift of a
workpiece typical surface roughness originates, namely cycloid waves. The waves are
characterized by their depth and the distance of their tops. This type of regular roughness is
termed as waviness. Roughness arising from the wood structure results from the nonhomogenous structure of wood and the different behaviour of early and late wood in the
course of machining. It is assessed as irregular waviness. Picking-up the wood fibres is also
234
related to the wood structure and behaviour. Torn bundles of wood fibres and microscopic
and macroscopic cavities on the wood surface are characterized by their roughness
(smoothness). The occurrence of this roughness is mostly irregular on the tooled surface.
Used material and the experimental stand
y
y
y
Evaluated species
¾ ring-porous broadleaves – oak, elm, ash
¾ diffuse-porous broadleaves – beech, birch, linden
¾ conifers – spruce, pine
Sample preparation
¾ on an experimental milling stand
¾ machine parameters – shaft speed 9000 rpm
¾ feed speed 21 m.min-1, chip thickness 2 mm
¾ milling head – diameter 125 mm, height 100 mm
¾ number of knives – 6, shaft bore – 40 mm
Evaluation process
¾ the Taylor Hobson company apparatus Talysurf CLI 1000
¾ confocal sensor
¾ 2 areas selected at each of the samples (17x17 mm), 3 sections at each of the
areas
Note: The preparation of samples was carried out on the experimental stand
Fig. 3. Experimental stand – a view of the workplace and motor place
A method of the surface quality evaluation:
An optical method was used based on the topography of surface by means of a
contactless confocal sensor CLA (Chromatic Length Aberration), which is part of a system
for the surface texture evaluation (Talysurf CLI 1000). This system can carry out evaluation
of the 2D (in total 117 parameters) and 3D (in total 40 parameters) surface structure.
The basic principle of the CLA confocal sensor is a fact that it does not create an image
as a whole, at a time, but step by step through scanning. Thus, optical points are taken by
means of scanning in the XY area and thanks to the accurate defined movement of the device
objective in the Z axis also particular optical sections. Confocal images are always focussed
representing particular optical sections through the sample. The composition of 3D images is
based on a possibility of the gradual scanning tens up to hundreds of optical sections in the Z
axis. Moreover, the confocal sensor uses the new intelligent software function of the
calculation of foci (CFO), which selects always only the best displayed parts to create an
235
image of the whole sample area. The speed of measurement, the more accurate quality of
measurements and 3D images rank among its advantages.
Methods of the surface quality evaluation using the Talysurf CLI 1000 apparatus:
1. Levelling the surface = levelling the surface according to the selected area
2. Zoom = the selection of an area from the measured surface for further adjustments and analyses
3. Form removal = serves for the geometrical shape separation at measuring real surfaces
4. Thresholding = including the corresponding spectrum of data into analyses
5. Obtaining the basic area
6. Filtration – obtaining the area of waviness and roughness
7. Depiction of the 3D area
8. Determination of 3D parameters of the area surface structure
Fig. 4. Evaluation of the surface quality using the Talysurf CLI 1000 apparatus
The surface of milled samples was evaluated using following parameters:
x
S - parameter – the surface amplitude parameter
x
R - parameter – a parameter calculated from the roughness profile
x
W - parameter – a parameter calculated from the waviness profile
x
Sa, Ra, Wa – the mean arithmetical deviation of a profile [ m]
x
Sq, Rq, Wq – the mean quadratic deviation of a profile [ m]
x
St, Rt, Wt – the total profile height [ m]
x
RSm, WSm – the mean width of a profile [mm]
x
Sz, Rz, Wz – the largest height of a profile [ m]
x
Gaussian filter 0.8 and 2.5 mm was used at evaluated parameters
RESULTS
Results of the surface quality measurement were processed using the Talymap program
in Talysurf system (see Fig. 8). An example is given of the 3D image of a beech sample, data
on roughness and waviness and a selected section of the 2D basic profile, waviness profile
and roughness profile.
236
2D basic profile
2D waviness profile
2D roughness profile
Fig. 5. Basic data on the surface quality of a beech sample from a PC
Through the processing of data it is possible to obtain waviness parameters, which can be
compared with theoretically calculated values. Fig. 9 illustrates that the actual length of waves
237
is higher than a theoretical value. Thus, an assumption is proved that all knives are not in
gear.
Annual ring – summer wood
Direction of the
sample
Direction of the tool
turning
Waves (5.5)
Wave top
The actual distance of waves – 2D profile of waviness
The theoretical distance of waves – 2D profile of waviness
Fig. 6. The profile of waviness of spruce at 9000 rpm, feed 20 m/min-1
238
Sa [ȝm]
Sq [ȝm]
5,38
6,89
70,30
62,60
Ra [ȝm]
Rq [ȝm]
Rp [ȝm]
Rv [ȝm]
Rt [ȝm]
RSm [ȝm]
1,30 1,16 1,72 1,60 1,21 1,77
1,67 1,49 2,22 2,08 1,53 2,22
3,07 2,76 4,18 3,67 2,87 4,29
3,77 3,14 5,04 4,88 3,30 4,81
13,80 11,95 18,10 17,60 12,00 15,89
0,26 0,26 0,26 0,27 0,26 0,26
1,62
2,05
4,03
4,05
15,20
0,29
2,53
3,30
16,58
7,39
27,98
0,30
roughness
parameters
8,83
10,90
parameters of
the basic area
112,00
Wa [ȝm]
Wq [ȝm]
Wp [ȝm]
Wv [ȝm]
Wt [ȝm]
WSm [ȝm]
3,45 2,87 2,53 3,23 2,71 2,78
3,80 3,30 2,92 3,64 3,13 3,16
2,58 2,62 2,84 2,76 2,71 2,90
2,66 2,62 3,00 3,15 2,49 2,92
18,78 17,30 16,00 20,25 15,33 15,52
2,90 2,33 1,80 2,37 2,19 1,78
4,35
4,94
3,68
3,96
25,32
2,19
3,97
4,53
4,08
4,18
26,97
2,15
waviness parameters
St [ȝm]
13,30 5,47 8,17 8,74 4,68 7,43
18,10 6,96 11,25 11,95 5,86 9,13
121,0 101,6
141,5
53,55 54,15
55,65
0
0
0
Spruce
10,75
14,50
parameters of
the waviness
area
Tab. 1. Values of roughness and waviness of experimental samples
Oak Beech Ash
Elm Birch Pine Linden
21,90 8,74 12,20 14,95 7,72 9,67
11,05
Sa [ȝm]
33,65 11,60 21,10 23,85 10,29 12,00 14,10
Sq [ȝm]
139,0 150,5
176,0
65,35 62,65 92,95
72,10
St [ȝm]
0
0
0
Density(12%)
725
[kg/m3]
Hardness
67,5
[MPa]
720
710
680
650
535
505
450
61
80
63
66
28,5
26
26
ring-porous broadleaves
diffuse-porous broadleaves
conifers
DISCUSSION AND CONCLUSION
Measured parameters of the surface quality were then processed in the form of wellarranged tables (table 1). Only changes of the waviness parameters of Wz (Fig. 7) were
processed in diagrams. Data on roughness were processed in the same way. However, these
are of marginal importance to evaluate the surface quality of a work-piece.
To assess the effect of conditions of high-speed milling and a tool used it was necessary
to evaluate particularly parameters of waviness and partly also parameters of roughness. By
means of parameters of waviness it is possible to monitor kinematic unevenness, i.e. the
process of high-speed milling, changes in the course of machining, machine and tool
instability, changes in the operation of a cutting tool. By means of the roughness parameter it
is possible to monitor effects of particular species on the surface quality or chipped (torn)
grain.
239
The mean arithmetic deviation of parameters of waviness Wa ranges from 4.21 m at
9000 rpm to 3.54 m at 10000 rpm in spruce and from 4.73 m at 9000 rpm to 3.92 m at
10000 rpm in beech. The mean quadratic deviation of the waviness profile Wq ranges from
4.69 to 3.98 m in spruce and from 5.3 to 4.41 m in beech. With the decreasing feed per
tooth these values diminish and, on the contrary, with increasing feed per tooth these values
increase.
SPRUCE 9000 rpm
1,00
9,50
9,00
1,20
1,40
8,50
1,60
8,00
1,73
1,80
7,67
2,00
7,50
[mm]
[ȝm]
9,11
9,07
2,01
2,00
2,20
7,00
18 m/min
Wz
20m/min
WSm
22m/min
Lineární (Wz)
Lineární (WSm)
BEECH 900 0 rpm
14,50
1,00
14,08
1,50
1,83
10,50
2,00
2,01
8,50
2, 57
7, 25
6,92
6,50
18 m/m in
Wz
WSm
20m /min
[mm]
[ȝm ]
12,50
2,50
3,00
22m/ min
Liniowy (Wz)
Liniowy (WSm)
Fig. 7. Dependence of the waviness parameter on the change of cutting conditions
The surface quality measurement was carried out by means of 3D spatial characteristics
making possible to process great number of data. The data then describe the assessed profile
of the monitored surface. It will be suitable to measure more samples, which can demonstrate
or disprove their dependence. Parameters of high-speed milling were selected with respect to
maximum rpm of ordinary machines. The feed of material into cut was chosen according to a
requirement to achieve the best possible quality surface. The average quadratic deviation of
the waviness profile Wq corresponds to the theoretical calculation of the waviness depth
being, however, about 2 m higher, which can be attributed to the imperfect torn grain and
thus, “hairy surface” originates. Differences in the Wq parameter among particular species are
negligible and the growth of Wq with the feed speed was demonstrated.
Finally, it is possible to note that main advantages of the proposed method are as
follows:
y it is possible to process a large number of data
y it is possible to predict surface properties
240
y it is possible to evaluate the surface preparation for spreading paint application
y the study of geometric and dimensional changes in various stages of the production
process.
REFERENCES
1. BARCÍK, Š., PIVOLUSKOVÁ, E., KMINIAK, R., WIELOCH, G., 2009. The
influence of cutting speed and feed speed on surface quality at plane milling of poplar
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geometrické struktury povrchu vznikající v procesu frézování d eva. VI.
Medzinárodná vedecká konferencia Trieskové a beztrieskové obrábanie dreva.
Št rovo 2008, s. 143-148. ISBN 978-80-228-1913-8.
3. LISI AN J., 1996, Teória a technika spracovania dreva vyd. Zvolen: Matcentrum,
4. 625 s. ISBN 80-967315-6-4
5. LIPTÁKOVÁ, E. – KÚDELA, J. 2000. Vlastnosti povrchu bukového dreva pri rôznom
spôsobe mechanického opracovania. In: Trieskové a beztrieskové obrábanie dreva.
Zborník prednášok II. MVK Trieskové a beztrieskové obrábanie dreva 2000, 19. – 21.
august Starý Smokovec, s. 107 – 116.
6. PROKEŠ S., 1965. Obráb ní d eva a nových hmot ze d eva, vyd. Státní nakladatelství
7. technické literatury Praha, 372 s.
8. ROUSEK M., 2004, Specifické problémy vysokorychlostního obráb ní d eva, vyd.
MZLU v Brn , 67 s., ISBN 80-7157-859-2 [monografie]
9. SANDAK J., (2008). Measuring wood surface roughness without contact. VI.
Medzinárodná vedecká konferencia Trieskové a beztrieskové obrábanie dreva.
Št rovo 2008, s. 201-206. ISBN 978-80-228-1913-8.
10. SIKLIENKA, M. – ŠUSTEK, J. – HAJNÍK, I., 2008. Kvantifikácia nerovnosti povrchu s
využitím laserového profilometra pri pílení na horizontálnej pásovej píle. In Trieskové a
beztrieskové obrábanie dreva ´08. Vydavete stvo Technickej Univerzity Zvolen, 2008, s.
207-212. ISBN 80-228-1674-4.
11. SVOBODA E. a kol., 2009. Surface structure of milling wood. Annals of Warsaw
Agricultural University – SGGW Forestry and Wood Technology No. 68.
12. SVATOŠ M., 2009. Kvalita povrchu p i frézování, Bakalá ská práce, MZLU v Brn ,
56 s.
13. UHLÍ P., 2010. Kvalita povrchu p i vysokorychlostním frézování. Diplomová práce,
Mendelova univerzita v Brn , 87 s.
14. EN ISO 4287 - Geometrické požadavky na výrobky (GPS) - Struktura povrchu:
15. Profilová metoda – Termíny, definice a parametry struktury povrchu
16. EN ISO 4288 - Geometrické požadavky na výrobky (GPS) - Struktura povrchu:
17. Profilová metoda - Pravidla a postupy pro posuzování struktury povrchu
241
Acknowledgement: This paper was prepared in connection with a partial project within the CR MSM
6215648902 Research Plan. The author thanks for a financial support to deal with the project.
The contribution was created during the solution of project CEEPUS network CII-SK-0310-03-0910 as a result
of activity and cooperation of authors.
Streszczenie: Problematyka jakoĞci obróbki frezowaniem uwzglĊdniająca wpáyw parametrów
obróbki na rodzaj drewna. Praca dotyczy pomiaru chropowato ci powierzchni p aszczyzn po
frezowaniu. Uwzgl dniono tak e wp yw parametrów na rodzaj drewna. Wyniki przedstawiaj
wyniki pomiaru chropowato ci o miu gatunków li ciastych (rozpierzch o oraz pier cieniowo
naczyniowych) oraz jednego iglastego przy u yciu metody topograficznej Talysurf. Ocena
jako ci powierzchni wybranych gatunków zosta a przeprowadzona na bazie parametrów
otrzymanych przy u yciu 2D oraz 3D. Ocena jako ci powierzchni zosta a przeprowadzona na
urz dzeniu Talysurf CLI 1000. Przeprowadzono ocen powierzchni przy u yciu pomiarów
dwu i trójwymiarowych.
Doc. Ing. Zden k Kopecký, CSc., Prof. Ing. Miroslav Rousek, CSc., Bc. Michal Svatoš,
Mendel University of Agriculture and Forestry, Faculty of Forestry and Wood Technology
Zem d lská 3, 613 00 Brno, Czech Republictel: +420 545134527
The Construction and Design of a Wicker Furniture Set from the Collection
of the Castle Museum in àaĔcut as a Criterion for Identification
ANNA RÓ A SKA, IRENA SWACZYNA
Department of Construction and Technology of Final Wood Products, Faculty of Wood Technology Warsaw
University of Life Sciences – SGGW
Abstract: The Construction and Design of a Wicker Furniture Set from the Collection of the Castle Museum in
àaĔcut as a Criterion for Identification. In the article, a furniture set in the chinoiserie style exhibited in the
Chinese Apartment of the Castle Museum in a cut was described. The construction features and the design of
the armchairs was analysed. These aspects indicate English origin of the furniture before 1800.
Keywords: chinoiserie, bamboo furniture, à la bamboo, English Regency furniture, furniture construction
ORIGIN OF THE FURNITURE
The set of painted furniture à la bamboo from the Chinese Apartment from the Castle
Museum in a cut comprises nine exhibited armchairs with the inventory numbers from S
2322 to 2324 M , from S 2313 to 3216 M , and from S 2441 to 2442 M (Ró a ska 2009).
The Chinese Apartment (fig.1) – just as Izabela Lubomirska’s other concepts –
constitutes the realization of a well thought-out intellectual, aesthetic and functional
programme. It can be compared with other apartments of that type: the Chinese Rooms from
Wilanów. The common features are as follows: the time of origin (beginning of the 19th
century), family relations of the originators, and the fact that the interiors have the character
of a (private or public) exhibition. The Apartment, completed about 1800, was based on a
romantic English version of chinoiserie, more ancient and exotic than Chinese in character
(Kossakowska-Szanajca, Majewska-Maszkowska 1964).
Fig.1. Izabela Lubomirska’s Chinese Apartment in a cut, Chinese Bedroom
243
THE CONSTRUCTION AND DESIGN OF THE FURNITURE
The armchairs are made of beech wood using the technique of turning and bending; the
construction uses rails (fig.2). The armchairs are totally covered with a non-transparent
brownish-green paint with white and ochre stripes, which makes the structure of wood
completely invisible. The seats are diagonally woven of raffia fibres, with the pattern
resembling that of an envelope. From the top, the weave is painted in black stripes which
form an interesting geometric pattern. Each armchair has four turned legs. The back legs,
which are made from the same piece of wood as the back rest, are slightly curved in the
middle and bent out. The bend point is on the top edge of the rail. A distorted diameter of the
back legs in the place of the bend may be evidence of the bending technique used. Trapezium
seats are wider at the front and slightly protuberant at the sides. The legs are joined at the
bottom with turned stretchers: the front one (placed a little higher), the side ones, and the back
one. The armchairs have openwork armrests and the back rest, filled with interspaced turned
thin pieces of wood. In the places where the front legs join the rail, there are cubes. The rail
construction consists of the front rail, the back rail, and the side rails fixed horizontally, which
also constitute the construction of the frame on which the seat is woven.
To join the stretchers with the legs, the horizontal elements of the back rest with the
back legs, the thin pieces of wood from the back rest with the horizontal elements of the back
rest, and the frame of the armrests with the back legs and with the thin pieces of wood from
the armrests, turned tenons were used, whose diameter was 2-4 mm smaller than the diameter
of the elements. It has been impossible to determine the type of joint between the cubes at the
top of the front legs and the rail, most probably, however, it is the mortise and tenon joint.
The joint between the armrests and the side rail is very interesting. The armrest supports go
through the side rails, cut out in these places (fig.3B). In the bottom part of the armrest
supports one can see marks left after round cover dowels used to hide the screws (fig. 3A).
These cover dowels are 15 mm in diameter.
In the construction of the wooden armchairs features typical of bamboo furniture are
used. In the places of joints, thicker parts imitating metal fittings (characteristic of bamboo
furniture) are turned or painted. In both cases, they are underlined by the use of white colour
with ochre bands. The back legs end in flattened spherical shapes, turned from the same piece
of wood, and painted ochre (the colour of wood), which imitates finials (they performed the
role of bungs) fixed onto the endings of rods in bamboo furniture.
The sizes of the armchairs differ. The height varies from 867 to 872 mm, the width –
537-574 mm, the depth – 475-490 mm, the height of the seats – 430 mm. They are
comfortable. The seats are wide (545 x 435 mm) and slightly lower at the front of the chair (to
10 mm), and the back legs are bent, which ensures comfort and stability. The armchairs are
elegant, designed in a refined way, with the construction using turned elements of various
diameters. The set is done correctly as far as its technical aspect is concerned.
CONSTRUCTION AND FURNITURE DESIGN ANALYSIS
The time of origin of the a cut furniture is specified in the Castle Inventory from
1802 and 1805 (Inwentarz Zamku a cuckiego 1802-1805), in which the furniture set is
mentioned as the original furnishings of the Chinese Apartment of Izabela Lubomirska. The
set must have been made before ca. 1800. Bearing in mind the Princess’s numerous trips, and
the novel character of the Apartment in Poland, one can assume that its furnishings were
specially ordered from French or English ébénistes, shortly before the Apartment was
finished.
The a cut set belongs to the group of objects called chinoiserie. They freely imitated
the character and ornamentation of oriental furniture. In fact, they were eclectic, they
244
combined motifs taken from Chinese, Japanese, Indian, Persian, or other eastern art, with
European furniture tradition, designed for a European user, which is why the characteristic
forms of the pieces of furniture differ from the Chinese models. Its style, however, differs
from the forms identified with Chinese art, even considering the European perspective. It has
only one common feature with the art of the Far East, namely the fact of imitating bamboo
furniture, which is customarily identified with Chinese art, just as lacquerware is identified
with Chinese or Japanese art. The style of the armchairs refers directly to Ancient Egyptian
patterns, both in the form and in the finish of the surface. Egyptian furniture was mainly
veneered, inlay was used, it was plated, gilded, or – as in the case of the a cut set – painted.
In the Chinese Apartment, there was also a wooden stool, inv. no.: S. 5900 (today in the
Pompeian Salon), whose form constitutes a faithful imitation of the form of Egyptian stools.
Combining Chinese, Japanese, Roman, Greek, Egyptian, or even Assyrian motifs is typical of
the furnishings of 18th-century English interiors. This trend intensified in the Regency era
(Edwards 1951,1955,1964). The a cut set seems to belong to this kind of furniture. Its
painting decoration is executed in brownish-green paint, and has white stripes which form a
narrow frame, highly popular in England of that time. Construction features: the way of fixing
the armrest supports (going into the side rails- fig.3B), and the way of concealing screw joints
of the armrest supports (by means of cover dowels- fig.3A), can also be seen in English
Chippendale armchairs from the a cut Castle Museum collection (inv. no.: PM 2086 and
S1055M ). This attribution is not disproved by features of the material and the type of the
wickering (woven diagonally, resembling the pattern of an envelope), which also indicate
England. The remaining construction features, e.g. the turned round-section tenons (not much
smaller than the diameter of the elements), rather testify to technological simplifications than
determine the environment. The features of the style and of the construction point to England
from the Regency period as to the place and time of origin respectively. This is not
contradicted by the entry from the Castle inventory from 1854-1855: “four English chairs
painted grey and white” (Inwentarz Zamku a cuckiego 1854-1855).
CONCLUSIONS
1. The construction features and the design of the a cut set give grounds for the
specification of the time and place of its origin.
2. The time of origin of the a cut furniture set is defined as “before 1800” in the Castle
Inventory from 1802 and 1805.
3. Another Inventory from the years 1854-1855 mentions the set as English. However, it is
not enough to assume that the set is of English origin. The term “English furniture” was
often used in Poland to refer to a type of Chinese-style furniture. What is more important
is the fact that the construction solutions used in the set are analogous to those used in
furniture of unquestionably English origin.
4. On the basis of the way of fixing the armrest supports to the side rails (in mortises in the
rails), and strengthening the joint with screws with characteristic cover dowels, the set
from the Chinese Apartment can be considered to have been made in England.
5. The material used and the type of the weave (resembling the pattern of an envelope) point
to England as to the place of origin of the pieces of furniture.
6. The set is styled on Egyptian furniture, fashionable in England during the Regency.
7. The pieces of furniture are completely covered with painting decoration, and the rails are
decorated with a motif of white stripes known from many English Regency pieces of
furniture.
245
Fig.2. Wicker armchair from the Chinese Apartment in a cut
A
B
Fig.3. Wicker armchair from the Chinese Apartment in a cut: A – the way in which the armrest support is fixed
to the side rail, the cover dowel visible; B – the joint between the rail and the armrest support, seen from the
bottom of the seat
REFERENCES
1. EDWARDS R., 1951: A History of the English Chair, London.
2. EDWARDS R., 1955: English Taste in the Eighteenth Century from Baroque to NeoClassic, [exhibition catalogue, the Royal Academy of Art], London.
3. EDWARDS R., 1964: The Shorter Dictionary of English Furniture, London.
4. Inwentarz Zamku a cuckiego 1802-1805, Archiwum G ówne Akt Dawnych [Central
Archives of Historical Records] – Zespó APK z
a cuta, Sygn. 784,
AGAD.AP .784.
246
5. Inwentarz Zamku a cuckiego w r. 1854 i 1855 spisywany, Archiwum G ówne Akt
Dawnych w Warszawie [Central Archives of Historical Records in Warsaw], Zespó
Archiwum Potockich, Sygn.785 Inwentarz Zamku 1854-55 AGAD.AP .785, p.38.
6. KOSSAKOWSKA-SZANAJCA Z., MAJEWSKA-MASZKOWSKA B., 1964: Zamek
w a cucie, Warsaw, 240-248.
7. RÓ A SKA A., 2009: Charakterystyka oraz konserwacja i restauracja wybranych
mebli w typie chinoiserie z historycznej kolekcji Muzeum Pa ac w Wilanowie
[Characterization, conservation, and restoration of selected pieces of furniture in the
chinoiserie style from the historical collection of the Wilanów Palace Museum],
master’s thesis, thesis advisor: Professor Irena Swaczyna, Faculty of Wood
Technology of the Warsaw University of Life Sciences, specialization: Antique Wood
Conservation, Warsaw.
Streszczenie: Konstrukcja i wzornictwo kompletu mebli wyplatanych ze zbiorów Muzeum
Zamek w àaĔcucie jako kryterium identyfikacji. W artykule opisano komplet mebli w stylu
chinoiserie, znajduj cy si w Apartamencie Chi skim Muzeum Zamek w a cucie.
Analizowano cechy konstrukcji i wzornictwo foteli. Na podstawie sposobu mocowania
podpory por czy pod okietnika do oskrzy bocznych (wpuszczenie w wyci cie w oskrzyni)
oraz jego wzmocnienie wkr tami z charakterystycznymi ko kami maskuj cymi, komplet
uznano za wyrób angielski. Tak e zastosowany materia i kopertowy wzór wyplotu jest
typowy dla Anglii. Komplet stylizowany jest na meble egipskie, modne w Anglii w okresie
Regencji. Meble pokryte s w ca o ci dekoracj malarsk a oskrzynie i kostki nóg
dekorowane s motywem bia ych ramek widocznych na wielu meblach angielskich z okresu
Regencji. Cechy te wskazuj na angielskie pochodzenie mebli z przed roku 1800.
Anna Ró a ska
Irena Swaczyna
166 Nowoursynowska str.,
02-787 Warsaw,
Poland
Design and Construction Innovation in Wicker Furniture Created by
Wáadysáaw Woákowski
ANNA RÓ A SKA
Abstract: Until the second half of the 20th century, wicker furniture was synonymous with outdoor furniture. If
the opinion that its design was eclectic seems exaggerated, it was at least traditional. It was only in the interwar
period in the circle of the “ ad” artistic group, and later from the 1950s as part of the activity of the Institute of
Industrial Design that attempts were made to define the new role of wicker furniture and, consequently, its new
forms. W adys aw Wo kowski was one of the first artists who designed wicker lounge sets intended for interior
use, both in private houses, and in public buildings.
Key words: wicker furniture, wickerwork, design
WICKER FURNITURE DESIGN IN POLAND
There are two interlinked currents in today’s wickerwork: the traditional, folk one, and
the new, artistic one. Polish wickerwork has its roots in folk culture. In folk culture, wicker
has many symbolical meanings. It symbolises Resurrection. Blessed wicker objects were
believed to protect people from lightning, bad weather, bad wishes, and illnesses. Wicker
baskets were a symbol of fertility.
At the same time, the interest in wickerwork is related to the ecological trend: ecological
design and ecological materials. This movement began in Europe in the 1970s. In the 20th
century the status of wicker became higher, which fact was connected with the fashion for
informal, separate pieces of furniture which did not belong to a set. Tired with the anonymous
character of industrial objects, people longed for handicraft products, for manual shaping, for
the decorativeness of natural materials. In the face of an abundance of substitutes, the
popularity of wool, linen, and pure wood increased.
In the interwar period, W adys aw Wo kowski was the only Polish artist who designed
wicker furniture. After the Second World War, Jan Kurz tkowski also started working with
wicker, but it was never his main field of interest.
When thinking about the inspirations for Wo kowski’s furniture, we have to consider
many factors. Wo kowski familiarised himself deeply with folk tradition in his home village
Sulis awice and in the school of Koszczyc-Witkiewicz. Studies at the Warsaw Academy of
Fine Arts gave the artist an international perspective and knowledge about the design rules. In
1937, his models of stools won renown at the Art and Technology Exhibition in Paris, and in
1939 – in the USA. Wo kowski cooperated with Polish wickerwork centres. During a break in
his studies at the Warsaw Academy of Fine Art, he went to Krzeszów. He also became
connected with wickerwork centres in Kra nik, Bi goraj, Rudnik, Stolart and Chro cice. He
founded a cooperative in Piotrków in the Bi goraj region. His connection with Rudnik seems
particularly important. On the other side of the river, there was a famous Austrian
manufacture. Hoffmann, the owner, employed 30 masters, and many products were exported.
It was there that the young Wo kowski got acquainted with the old Vienna school of
wickerwork (Janneau 1978). Thanks to the favourable attitude of the directors, he managed to
work with wicker at every stage of production, learning about the stages of producing a
wicker object from the masters. He also spent much time in the local museum, where a
collection of wickerwork from various countries and periods was housed.
248
It was Wo kowski who initiated the interest in wicker among furniture designers, and
who created the trend whose outstanding representatives were Witold Gyurkowicz from
Pozna , Irena mudzi ska, Hanna arska, and Zbigniew Majchrzak from Warsaw. The
promoter, organiser, and the centre of wicker handicraft in Poland became Cepelia.The
takeover of five wickerwork cooperatives having important export orders by Cepelia made it
necessary to introduce design to wickerwork handicraft. Therefore, in Cepelia Research and
Development Centre in Warsaw a design and production studio was created. Its director was
Zygmunt Majchrzak, an artist; other artists working there were e.g. Hanna arska and Irena
mudzi ska. Artists realised their designs themselves. In the 1970s, Cepelia organised
wickerwork workshops in Greater Poland. In 1985 and 1987, International Wickerwork
Workshops were organised thanks to Cepelia, a member of the World Crafts Council
(Sterni ska 1987).
Wo kowski’s wickerwork activity raised the status of wickerwork items, and imparted
elegance to them. Wicker objects became perceived as our exports of a specifically Polish
character. They became our flagship products. Polish embassies were furnished with wicker
furniture, and at the Sevilla EXPO ’92, wicker furniture filled a large terrace in the Polish
Pavilion (together with a wicker installation by J drzej St pak).
THE DESIGN AND CONSTRUCTION OF FURNITURE CREATED BY
WàADYSàAW WOàKOWSKI
The seemingly complicated technique of weaving boils down to a couple of weaves.
The knowledge of the weaving techniques was common. Each of the techniques had their own
local varieties, which was why the weaves seemed diverse.
The wickerwork regions do not correspond with the ethnographic regions. They are rather
places rich in raw material: along rivers (on the Vistula, San, Pilica, Dunajec, Bug and other
rivers) or in forests of the former wildernesses (e.g. the Kurpie Forest, the Sandomierz
Wilderness). In Poland one cannot distinguish any specific regions characterised by a
particular type of wickerwork. More or less similar forms and techniques were found
everywhere (Pokropek 1978). However, there were regions where wickerwork was popular
(e.g. Mazovia, Podlasie, the Lublin area, and the eastern Lesser Poland), where it did not gain
popularity (e.g. the Carpathians), or where its popularity quickly faded away (Silesia, Greater
Poland) (Fry -Pietraszkowa, Kuczy ska-Iracka, Pokropek 1988).
Wo kowski introduced wickerwork used in craft objects and folk art to decorative art.
The difference between the form and the material disappeared in his works. Sometimes the
wickerwork only filled larger surfaces enclosed with a wooden frame, but it usually
constituted the main part of the item, and dominated the piece with its decorative value. The
status of the wickerwork determined the fact to which of the above-mentioned types the piece
of furniture belonged. The material used (wicker, cane, sometimes string, straw, or narrow
tubes covered with fabric) also decided about the character of the object.
In the first type of furniture, where the wickerwork had a supplementary character
(played the role of the back rest or seat), the frame was made of wood or, less often, metal.
The clear division into the frame and the material used to fill it was underlined not only by the
difference between the materials and their character (soft – hard), but also by the colour
contrast.
Chairs, armchairs, stools, and small tables belonging to the second type of furniture,
namely furniture entirely made of wicker, had a soft and flexible line. They were made of
tightly woven wicker, covering the bent metal frame of the object. The role of the wickerwork
was totally different. It did not have various motifs, it was monotonous. It became a part of
the construction, not a decoration. The artist modelled the wickerwork perfectly, adapting it to
the shape of the human body, and giving it modern forms.
249
Each set created by Wo kowski had a name given to it by the author. Some were
connected with nature (e.g. “Flower Sets”, “Bears”, “Snails”, “Goats”), some with the Polish
countryside (“Chocho y [Straw Covering]” – based on Kraków folk themes, or “Kurpie” –
using folk motifs from that region), and some with the character of the set (“Hooligan”,
“Modern”). Each piece of furniture had its atmosphere. It could belong to the “lazy”,
“energetic”, or “cheeky” group. Their shapes, the invisible light construction, and the space
contained in the objects were fascinating.
Fig.1, 2. Armchair “Hooligan” (1), before 1957 and chair from the set “Goats” (2), before 1966 - Wo kowski
Museum in Olkusz
Fig.3, 4. Armchair “Whirl” (3) and chair from the set “Bachmaty [Tatar Horses]” (4), before 1967 - Wo kowski
Museum in Olkusz
250
CONCLUSIONS
Wo kowski belonged to the tradition of the Polish folk decorative art in which the form
resulted from the character of the material and was connected with the purpose of the object
(e.g. children’s furniture for nursery schools was shaped like the letters of the alphabet).
Wo kowski’s wicker furniture was very modern. He was both a folk artist and an industrial
designer. This was fascinating and not surprising, as the basic composition principle of folk
objects was the inseparability of the design and the realisation from their purpose. Folk
products were characterised by integration: treating artistic tasks as a whole (Telakowska
1970). Wo kowski’s wickerwork was not a transposition of folk motifs; they were rather a
source of inspiration. The artist used the material to the fullest extent, and the works were
characterised by unity of the form and the material. Wo kowski combined various types of
weaves, he contrasted densely woven fragments with openwork fragments, straight lines with
arched lines, and broke the discipline with freedom. Only after having acquired the shape
given to it by Wo kowski, did wickerwork, woven straw, or any other kind of woven material
become a work of art equal to other works commonly recognised as possessing artistic value
(Grabowski 1955, 1956).
REFERENCES
1. GRABOWSKI J., 1955: Wystawa prac W adys awa Wo kowskiego. Plecionki, meble,
rysunki, 1954/1955, Centralne Biuro Wystaw Artystycznych, Warsaw , 3-11.
2. GRABOWSKI J., 1956: Mistrz rytmiki i splotu, "Przemys Ludowy i Artystyczny",
no. 1.
3. JANNEAU G., 1978: Encyklopedia Sztuki Dekoracyjnej, Michael Thonet (1796-1871),
Warsaw, 278.
4. STERNI SKA I., 1987: Wzornictwo „Cepelii”, [in:] Wzornictwo w Polsce, collective
work, Biblioteka Wzornictwa, no.1, 49-58.
5. TELAKOWSKA W., 1970: W kr gu ch opskiej kultury. Inwencja ludowa we
wspó czesnej wytwórczo ci, Warsaw, 38.
Streszczenie: Wzornicze i konstrukcyjne nowatorstwo mebli wiklinowych Wáadysáawa
Woákowskiego. Meble wiklinowe do drugiej po owy XXw. tradycyjnie uwa ane by y za
meble plenerowe. Ich wzornictwo by o je li nie eklektyczne, to przynajmniej tradycyjne.
Dopiero w kr gu ugrupowania artystycznego „ ad” w okresie Dwudziestolecia
Mi dzywojennego oraz od lat 50-tych w ramach dzia a Instytutu Wzornictwa
Przemys owego podj to próby sformu owania ich nowej roli, a co za tym idzie i nowych
form. Jednym z pierwszych artystów, projektuj cych wiklinowe komplety wypoczynkowe
przeznaczone do wn trz mieszkalnych i u yteczno ci publicznej by W adys aw Wo kowski.
Wo kowski to pionier polskiego meblarstwa z wikliny. Nie tylko podniós rang
niedocenianego dot d materia u, ale te stworzy z niego kreacje cz ce awangardow
nowoczesno z tradycj ludow . Dzi meble z wikliny to jedna z czytelnych ikon polskiego
meblarstwa wspó czesnego.
Anna Ró a ska
(Ann. WULS - SGGW, For. and Wood Technol.,72, 2010)
Multi-recovery of specific waste biomass for production environmetally
friendly products. Part 1. Preparation of new type wood materials
EVA RUŽINSKÁ1), ANNA DANIHELOVÁ1), MAREK JAB O SKI2), MARCIN ZBIE
1)
2)
2)
Technical University in Zvolen, Slovakia
Faculty of Wood Technology, Warsaw University of Life Sciences – SGGW, Poland
Abstract: Multi-recovery of specific waste biomass for production environmetally friendly products. Part 1.
Preparation of new type wood materials. The article deals with effective utilization of biomass waste (from
cellulose pulp and paper industry) for production of new type of wood products. Multipurpose utilization of
waste sulphate liquors is possible as environmentally acceptable adhesive mixtures for preparation special wood
composite materials. Next declining biomass waste is as compostable materials available for the treatment of
forest roads and for the purpose of fire protection.
Keywords: recycling, waste, biomass, wood products
INTRODUCTION
This is currently the preferred multi-use waste as a valuable secondary raw materials.
Increasing the efficiency of biomass waste must be conducted in real ecological situation in
terms of reducing the quality of biomass waste, improving the quality characteristics of
recycled products and meeting the current requirements for hygiene, in particular the
ecological quality of the proposed application of waste products, e. g. wood composite
materials (Mašura, 1998; Jolly, 1992).
In the preparation of kraft pulp, which is the main intermediate product in the pulp and
paper industry, is due to the ongoing process to create delignification reactions quantities
of waste products, f. e. kraft black kraft liquor. New kraft recovery of waste liquor is aimed
only for the use of certain components to produce liquors of high prices, e. g. derivatives such
as kraft lignins or modification reactions modified kraft black liquor that can be applied in the
preparation of composite wood materials (plywood panels, agglomerated material)
(RUŽINSKÁ, 2003) as adhesive hygienically acceptable and economically than currently used
polycondensation - fenolformaldehyde (PF) resin (OLIVARES ET AL., 1995). Recovery of toxic
constituents (as phenol) in polycondensation adhesives just natural polyphenols (of kraft
waste liquor) obtained from chemical processing of biomass is more efficient to use in the
preparation of materials with high added value (SHIMATANI, 1995; VASQUEZ ET AL. 1997).
The reactivity of lignins to formaldehyde is one of the indicators of their suitability
for use in the PF adhesive. The chemical structure of sulphate lignins (in kraft liquor),
especially aromatic character fenylpropane units allows a number of modification reactions
and to an increase in their reactivity and better crosslinking into polycondensate matrix
of adhesive mixtures (ALLAN, 1989; OLIVARES ET A., 1995, RUŽINSKÁ, ET AL. 2008, 2010).
The first part of paper deals with the efficient use of waste products prepared
from the processing of biomass (production of chemical pulp – sulphate black liquors)
for the preparation of composite wood materials the environmental attributes of acceptability
while preserving the quality characteristics designed and laboratory prepared materials.
In the experimental part of the attention modifier treatment kraft liquor, which were
subsequently applied to the reciprocal laboratory prepared glue mixtures. The comparison was
252
designed and prepared various variant adhesive mixtures which are used unmodified kraft
black liquor. Prepared mixtures of glue (with reciprocal compensation commercial PF resin
10 – 60 % wt.) was used in the laboratory preparation of composite wood materials – three
layers particle board (PB). They were subsequently evaluated selected physical and
mechanical properties of laboratory particle board which were compared with a standard
manufactured wood composite (PB).
Modified treatment of waste liquor
Methylolation treatment of kraft black liquor has been carried out experimentally
The basis of methylolated treatment was the reaction of formaldehyde with waste sulphate
liquor at room temperature for 72 hours. The way was prepared methylolated kraft liquor,
which was further applied to the adhesive mixture with fenolformaldehyde adhesive (PF) with
a gradual proportional refund PF adhesives from 10 to 60 % wt. (DOLENKO, 1978).
Acidification kraft black liquor is the second variant of the modification adjustment
was in the previous post-treatment procedure prepared methylolated kraft liquor acidification
followed by a strong mineral acid with intensive stirring to value pH = 5 (SHIMATANI, 1995).
Preparation of adhesive mixtures
Adhesive mixture to be applied in the preparation of composite wood materials (PB)
were prepared with the gradual replacement of the original proportional fenolformaldehyde
adhesive (PF) native and modified liquors gradually from 10 to 60 % by weight. Similarly the
reference test were used units - only with PF adhesive glue mixture consisting only of origin
kraft black liquor (100 % wt.) (RUŽINSKÁ ET AL. 2008; 2010).
Laboratory preparation and evaluation properties of particle board
Experimental prepared three variants of three-ply particle board (PB) mixed
with the application of mixtures adhesives:
- A variant: PB with the application of the original, untreated kraft liquor,
- B variant: application of modified PB - methylolated liquor,
- C variant: application of the modified PB - acidified liquor,
Conditions for the preparation of particle boards:
- moisture content of particles: surface 5,01 %, middle 3,64 %,
- a mixture of glue deposits at the surface 10 %, in the midlle 7 %,
- prepared PB dimensions: 280 x 360 x 16 mm (three-layers beech PB),
- pressing conditions: 195 °C, specific pressure of 4,8 MPa, total pressing time 480 s.
Evaluation of selected physical and mechanical properties of laboratory prepared
particle boards:
- tensile strength perpendicular to the plane of the plate according to STN EN 319,
- the swelling diameter in water (20 ± 2 °C) for 2 hours and 24 hours according
to STN EN 317.
Laboratory particle board were prepared to gradually replace (from 10 to 60 % wt.)
the original reciprocal fenolformaldehyde adhesive by waste sulphate liquor – origin and
modified
liquors as variants A, B, C. The mechanical properties were assessed
as representative of the characteristics - tensile strength perpendicular to the plane of the plate
(three layers particle boards). Evaluation of mechanical properties was carried out
in the program Statistics.
253
Categorized Plot for Variable: PK
1,4
1,1
0,8
0,5
0,2
A
B
C
A
PK
B
C
A
ZAST:
10
ZAST:
0
B
C
ZAST:
20
1,4
1,1
0,8
0,5
0,2
A
B
C
A
B
C
ZAST:
40
ZAST:
30
A
B
C
ZAST:
50
1,4
1,1
0,8
0,5
0,2
A
B
C
A
B
±1.96*Std. Err.
C
±1.00*Std. Err.
ZAST:
100
ZAST:
60
Mean
UPRAVA
Fig. 1 Mutual comparison of confidence intervals for mean values of tensile strength perpendicular the plain
laboratory prepared particle board to changing for three various particle boards
Categorized Plot for Variable: NAP
9,0
CAS: 2
7,5
6,0
NAP
4,5
9,0
CAS: 24
7,5
6,0
±1.96*Std. Err.
±1.00*Std. Err.
4,5
0 10 20 30 40 50 60
0 10 20 30 40 50 60
0 10 20 30 40 50 60
UPRAVA: A
UPRAVA: B
UPRAVA: C
Mean
ZAST
Fig. 2 Confidence intervals the average swelling of laboratory prepared particle boards for exposure
2 and 24 hours ( A - origin black liquors, B – methylolated liquors, C – acidified liquors)
In the Fig. 1 are evaluated confidence intervals for tensile strength perpendicular
to the plane of the plate (prepared PB) for different variants of the test pieces. Results
in Fig. 1 are showed that laboratory prepared particle boards with a gradually increasing share
254
of reciprocal kraft waste liquor (to replace the original PF resins) comparable strength
characteristics: A variant in 20 % wt., variant B to 30 % wt., variant C to 40 % wt. compared
to the reference sample (designated as 0 % wt. - PF resin bonding only). Even
the experimental particle boards prepared with 100 % wt. replacement PF resin (variant C)
has such mechanical properties that meet the quality particle board general use (type N)
for thickness 22 mm or more: 0,25 MPa.
The physical characteristics as representative of swelling was evaluated after 2 and 24
hours of exposure in water (20 ± 2 °C). The assessment is clear that the particle boards
prepared with the application of modified kraft effluents (variant B, C) demonstrated
reduction of swelling after 2 and after 24 hours compared with variant A (the presence
of untreated sulphate liquor). Variant A in the evaluation of swelling showed similar swelling
values than the reference sample (0 % by weight). There was a significant reduction
in swelling after 2 hours was just a variant B and variant C up to 30 % by weight reciprocal
compensation PF resin modified extracts. Even reciprocal compensation in the range 40 60% wt. the observed physical property decreased only slightly. The assessment of the
diameter of the swelling after 24 hours has been shown to reduce the swelling experimentally
prepared PB significantly to 30 % by weight, moderate in 40 – 60 % wt. comparable in both
models, but better results once again demonstrate variant C.
CONCLUSION
Waste kraft black liquor containing natural polyphenolic substances which are showed
very good adhesion characteristics and confirmed the suitability of their application
for reciprocal compensation phenolformaldehyde resins by waste sulphate liquor using
experimentally prepared composite wood materials - particle board with improved quality up
to 30 % by weight. reciprocal compensation (in comparison PF resin) a variant of C - using
acidified sulphate liquor.
From evaluation of selected physical characteristics of prepared particle board
followed that the application of modified kraft liquor specifically reduced swelling laboratory
prepared particle board after 2 and after 24 hours compared with commercially produced
particle boards assembling only with the use of PF resin. Even compared to the reference
sample (0 % wt.) was recorded experimental reduction of swelling diameter for prepared PB
in all three variants for two after 24 hours with the most favorable results for variant C.
REFERENCES
1. ALLAN C.G. et al. 1989: Adhesives from renewable resources. ACS Symp. Ser. 385.
2. DOLENKO A.J., CLARKE M.J. 1978: For. Prod. J., Vol. 28, 8.
3. JOLLY et al. 1992: Holz-Roh-und-Werkstoff, 50, 7.
4. MAŠURA V. 1998: Papír a celulóza, 43, 3.
5. OLIVARES et al. 1995: For. Prod. Journal, Vol. 45, 1.
6. RUŽINSKÁ E., JAB O SKI M. 2008: Annals of Warsaw Universtity of Life
Sciences – SGGW. Forestry and Wood Technology, No 64, (2008). p. 232-237. ISSN
1898-5912.
7. RUŽINSKÁ E. 2002: Papír a celulóza, 57, 5.
8. RUŽINSKÁ E., DANIHELOVÁ A. 2010: Chemické listy, Vol. 104, 6, p. 529-530.
9. RUŽINSKÁ, E., MARKOVÁ, I.: Chemické listy, Vol. 104, 6, p. 568 (2010).
10. SHIMATANI K., SANO Y. 1995: Holzforschung, Vol. 49, 4.
11. VASQUEZ G., GONZALES J., FREIRE S., ANTORRENA G. 1997: Biores.
Technol., 60, 3.
255
Streszczenie: Wielokierunkowe wykorzystanie biomasy odpadowej do produkcji produktów
ekologicznych. CzĊĞü 1. Przygotowanie nowych rodzajów materiaáów drzewnych.
W artykule omówiono efektywne wykorzystanie biomasy odpadowej (powstaj cej w
przemy le celulozowo-papierniczym) do wytwarzania nowych rodzajów wyrobów
drzewnych. Wykorzystuj c wielokierunkowo odpadowe ugi siarczanowe mo na otrzymywa
przyjazne dla rodowiska masy klejowe, które nast pnie mog by stosowane w produkcji
specjalnych drzewnych materia ów kompozytowych. Dalszym zastosowaniem odpadów
biomasy z odzysku, mo e by np. ich wykorzystanie jako materia u kompostowalnego do
naprawy dróg le nych oraz jako rodków w ochronie przeciwpo arowej.
Work is published with support of Grant Agency of Slovak Republic Ministry of Education VEGA
nr. 1/0841/08 „Wood characteristics its quality with application to production of special products”.
Eva Ružinská a, Anna Danihelová b,
a
Faculty of Environmental and Manufacturing Technology,
b
96053 Zvolen,
Slovakia,
Marek Jabáo ski, Marcin Zbie ,
07-776 Warsaw,
159 Nowoursynowska st.,
Poland,
e-mail: [email protected],
Multi-recovery of specific waste biomass for production environmetally
materials. Part 2. Evaluation selected characteristics of sulphate waste
liquor for their energy utilization
EVA RUŽINSKÁ1), ANNA DANIHELOVÁ1), IVETA MARKOVÁ1),
MAREK JAB O SKI2), MARCIN ZBIE 2)
1)
2)
Faculty of Wood Technology, Warsaw University of Life Sciences – SGGW, Poland
Abstract: Multi-recovery of specific waste biomass for production environmetally materials. Part 2. Evaluation
selected characteristics of sulphate waste liquor for their energy utilization. The article deals with effective
utilization of biomass waste (from cellulose pulp and paper industry) for environmetally accepted materials. The
second part of the paper is devoted to another utilization of kraft waste effluents from the aspect of their thermal
characteristics to assess their suitability as energy use. Attention is given to the evaluation of selected thermal
characteristics of kraft effluents calorimetric methods.
Kay words: biomass, waste, recovery, thermal characteristics
INTRODUCTION
The issue dealt with in the second part of the paper builds on the multifunctional
recovery of specific waste biomass. The focus in the second part of the paper is devoted
to another way utilization of kraft waste effluents from the aspect of their thermal properties
to assess their suitability as energy use or for specific purpose of ecological fire protection
substances (Marková, 2010; Ružinská and Jab o ski, 2008; Kubo et al. 1996).
The method of preparation of sulphate pulp (the pulp and paper industry) is due to the
ongoing delignification processes to create large quantities of waste products, e. g. black kraft
liquors. At present, the organic components are burned kraft effluents – liquors, which uses
in the recovery process and provide the thermal energy and carbon needed to reduce sodium
sulfate to sulfide, as one of the components boiling solution required to regenerate each cycle
in the production of kraft pulp (MAŠURA, 1998).
Such use of the waste - black kraft effluents is not the optimal way to recovery their
effective use in terms of technology, since it is prepared products with higher added value,
f. e. wood composite materials containing treated waste kraft black liquor in combination with
polycondensation adhesives. Such an experiment designed and prepared wood composites
(plywood and particle board) showed similar characteristics were compared with
a standard generated wood materials, but with significant economic savings and significant
environmental aspects - the reduction of emissions of gaseous pollutants (reduction of the
formaldehyde releasing of prepared glue mixtures in reciprocal compensation PF adhesives
modified sulphate liquors) (RUŽINSKÁ ET AL. 2010).
Currently looking for ways to make efficient use of waste products - kraft liquor, f. e.
well as energy recovery. To assess the suitability of the proposed application, it is necessary
to know the thermal properties of these waste products in the original and in modified form
(CHRISTIANSEN, 1985).
The second part of paper deals with the efficient use of waste products prepared
from biomass processing (production of chemical pulp – sulphate black liquors)
for the for recovery in the energy field, using thermal characteristics these specific waste.
257
In the experimental part of the attention unmodified, origin kraft black liquor from
production of chemical pulp – sulphate black liquor (4 samples). The moisture content
of kraft black liquor - 50.49 %.
Calorimetric method
For purposes of the experiment to monitor the behavior of matter at the complete
combustion of the defined terms used in the IKA device calorimeter C 5000 control, designed
to measure and determine the calorimetric heat and caloricity of solid and liquid substances.
Fig. 1 Equipment IKA CALORIMETER C 5000 control
Based on experiments carried out under ISO 1928 values were calculated heat
of combustion (calorimetric heat), caloricity and the residual ash after the experiment. The
obtained results are showed in Tab. 1.
Tab. 1 Experimental results obtained from calorimetric methods evaluation of calorimetric heat, caloricity and
content of ash samples (moisture content 50,49 %)
Measurements
1
2
3
4
Average
Calorimetric
heat
(J.g-1)
3 679,32
3 854,69
3 811,25
3 736,33
3 770,40
Caloricity
(J.g-1)
1 885,71
2 061,08
2 093,51
1 942,72
1 995,75
Content
of ash
(%)
23,20
24,51
25,17
24,20
24,27
RESULTS
Based on the results it can be concluded that prepared mixtures (with unmodified origin kraft black liquors as waste product) is not suitable for combustion purposes, compared
with the calorimetric heat down other organic fuels (MARKOVÁ ET AL. 2010).
258
Inappropriateness of applying the test material for the purpose of combustion also
results in a graphic depending on temperature rise depending on the time course
of the experiment (Fig. 2).
19,8
19,6
19,4
teplota (°C)
19,2
19
18,8
18,6
18,4
18,2
18
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
þas (min)
Fig. 2 The graphic dependence of temperature rise during the calorimetric test sample compostable
mixture depending on the time
Seeks materials for the purpose of firing is the perfect combustion of fuel the whole
stake in the shortest time, which means a sharp temperature rise in a relatively short time.
The condition does not meet the test material. Also, for the combustion process is the total
volume of fuel burned evenly. In the case of fuel monitor residual shares in the form of ash.
For the sample was too much ash content as incrusting substances (MARKOVÁ ET. AL, 2010).
CONCLUSION
Results of calorimetric methods were compared with the conclusions of thermal
analysis (TG, DTG, DSC – Ružinská et. al., 2008; MARKOVÁ ET. AL, 2010), which shows that
the kraft black liquor showed low thermal stability, but low calorific value.
It is clear that the effective recovery of waste effluents sulphate for the preparation
of products with higher added value should be primarily directed towards their use for the
preparation of new composite wood materials and energy recovery for commercial purposes
is not appropriate, especially for low calorific value and high incrusting substances.
REFERENCES
1. CHRISTIANSEN A.W., GOLLOB L. 1985: J. Appl. Polym. Sci., Vol. 30, 8, p. 2279 2289.
2. KUBO S. ET AL. 1996: Holzforschung, Vol. 50, No.2, p. 144-150.
3. MARKOVÁ I. 2010: Chemické listy, Vol. 104, 6, p. 566.
4. MARKOVÁ I., RÉH R., ORÉMUSOVÁ M. 2010: Acta Fac. Xylol., XXII, 2, in
press.
5. MAŠURA V. 1988: Papír a celulóza, 43, 3.
259
6. RUŽINSKÁ E., JAB O SKI M. 2008: Annals of Warsaw Universtity of Life
Sciences – SGGW. Forestry and Wood Technology, No 64, p. 232-237. ISSN 18985912.
7. RUŽINSKÁ E., DANIHELOVÁ, A. 2010: Chemické listy, Vol. 104, 6, p. 529-530.
8. RUŽINSKÁ E., MARKOVÁ I. 2010: Chemické listy, Vol. 104, 6, p. 568.
Streszczenie: Wielokierunkowe wykorzystanie biomasy odpadowej do produkcji produktów
ekologicznych. CzĊĞü 2. Ocena wybranych cech áugów siarczanowych w aspekcie ich
wykorzystania energetycznego. W artykule omówiono efektywne wykorzystanie biomasy
odpadowej (powstaj cej w przemy le celulozowo-papierniczym) do wytwarzania nowych
rodzajów wyrobów drzewnych. Cz
druga po wi cona jest dalszemu wykorzystaniu
odpadowych ugów siarczanowych z punktu widzenia ich w a ciwo ci termicznych w celu
oceny ich przydatno ci do wykorzystania energetycznego. Termiczne w a ciwo ci ugów
siarczanowych zosta y oznaczone metod kalorymetryczn .
Work is published with support of Grant Agency of Slovak Republic Ministry of Education VEGA
nr. 1/0841/08 „Wood characteristics its quality with application to production of special products”.
Eva Ružinská a, Anna Danihelová b, Iveta Marková b
b
96053 Zvolen,
Slovakia,
a
Marek Jab o ski, Marcin Zbie ,
07-776 Warsaw,
Poland
Improvement of Industrial Equipment for Wood Biofuel Production
A.O. SAFONOV1, V.V. BELYKH2
The Dean of the faculty of wood processing technology of Voronezh State Academy of Forestry and
Technologies,
8, Timiryazeva str, Voronezh, Russia.
Head of procurement and marketing department of Department for Presidential Affairs of Federal State Unitary
Enterprise “Construction Association”, Arkhangelskoye, Krasnogorskiy dist., Moscow region.
Abstract: Improvement of industrial equipment for wood biofuel production. The article is devoted to
development of the system of automatic equipment control. Research has been referred to increase of technical
and economical effectiveness of biofuel production. Energy saving for pressing is 30-35 %. In aggregate all the
advantages provide sufficient of general technical and economical effectiveness of the process.
Keywords: biofuel, equipment, process, technology, wood.
Quantity of small-scale enterprises in the world is growing, volume of processed wood is
increasing every year. In connection with it, the question of target processing of the waste
materials into biofuel [1]. However special-purpose equipment for processing of dispersed
wood waste into biofuel is rather expensive and needs additional expenses, connected with its
maintenance. Such inputs are low-profit for most of middle and small wood processing
enterprises. At present, a following tendency is marked: lines, which are used in agriculture
for pelleted feeds production, are being re-equipped, for getting wood biofuel [2]. Such a
complex, intended for pelleting grasses, as a rule, can be equipment, examined in this article.
This equipment includes: drum drier with loading conveyor, mill for refinement, bunker,
press-granulator, quenching chamber. While installing specialized matrix with ruggedness,
necessary resetting of drier drum and including the second additional mill into the line, the
complex manages to granulate dispersed wood waste into quality biofuel, in conformance
with EU standarts.
During the research the analysis of the current automation system has been made.
Controlling of batcher, conveyor, getting raw material into a bunker, transfer conveyor of hot
granules, conveyor of cooled granules, bunker fanner, feeder screw, screw conveyor of nongranulated mass, quenching chamber and non-granulated mass blower is made form the
control board. Registration of rotation frequency of a screw conveyor and current strength in a
chain are displayed in a control board. Switching on of all above-mentioned equipment is
made manually with the help of buttons “On/Off” on a control board. Necessary rotation
frequency of feeder screw is driven by hand on a board of electronic frequency converter,
built in control board.
However, such production is non-fireproof and quality of biofuel (wood pellets) widely
varies, depending on different factors, which can be divided into controlled and uncontrolled.
Controlled regulated parameters of technological process are: speed of supplying wood
shavings, rock compound of raw material, moisture of supplying shavings, temperature of
press matrix, breakup of raw material.
Uncontrolled parameters are: atmospheric humidity, atmospheric temperature, raw
material temperature.
In this case, output parameters of technological process, characterizing production
effectiveness, are as follows: combustion value of the pellets, prime costs, useful output of
final product, crumbliness.
We examine influence of output parameters on technical and economical rates of the
process. Speed of supplying depends on raw material characteristics – its humidity, fractional
261
structure and matrix temperature. When the moisture of raw material is higher (more than
10%), it is recommended to increase speed of supplying to reduce intensiveness of moisture
processing.
In this case, when average raw material fraction size exceeds 3 mm, speed of supplying
must be reduced for necessary strength of finished pellets. When matrix temperature is not
enough (less than 50 ), speed of supplying must not be high. It is connected with the
difficulty of lignin plasticization in raw material.
Lignin, contained in wood, is a binding agent while pressing. During the pressing process
raw material goes through press matrix, which highly heats because of roller friction on
matrix, so the lignin in wood melts. After pellets go through cooling operation, lignin hardens
again and provides necessary strength of final product.
Moisture of supplying shavings defines final moisture of pellets and, as the result, their
strength. When raw material is hypermoistured (more than 16%), it is difficult to lead
technological process, because the pellets really go-off from matrix.
If moisture of raw material, supplying into press is 12 – 15 %, when ready pellets are
crumb, unstrengh and can not be qualified final product. If moisture of raw material is less
than 7 %, pellets also don’t have necessary strength characteristics. It can be explained by
lack of binding moisture for lignin, necessary for strength link of wood compounds. Lack
moisture of raw material can be compensated by moisture processing.
Raw material breakup essentially influences on technological process efficiency. Than
less the breakup, than higher the efficiency. For getting nominal efficiency, size of particles at
input on line of drying and reducing must be not more 25 25 1 mm, and at the output in
press-granulator - 2 1 1 mm. In connection with it, at enterprises there are hammer mills for
getting necessary breakup compound from large waste materials.
Press matrix temperature, during the production process varies from the temperature of
environmental air till 95 . Matrix heating takes place under the influence of high pressure
and friction on matrix walls of pressing valves in production process. It defines melt
intensiveness of lignin and quantity of biofuel.
Combustion heat is a quantity of heat, escaping through a full firing of 1 kg of wood. This
index depends on density of biofuel, i.e. quantity of wood in unit of volume.
One of the main characteristics of effectiveness of most productions is prime cost ( ),
which depends on energy consumption ( e), needed for equipment functioning, transport and
storage cost of raw material (E), divided by volume of final product (V):
V
,€
(1)
Energy cost is calculated according to a formula:
e
P
g
Ps Pct Pf Ptc Ptb C kh
(2)
where Pg – granulator power consumption; Ps –power consumption of a screw, getting raw
material into granulator, kilowatt; Pct –power consumption of transporter, getting raw material
into bunker, kilowatt; Pf –poaer consumption of a fan in quenching chamber, kilowatt; Ptc –
power consumption of transporter in quenching chamber, kilowatt; Ptb –power consumption
of transporter, which move made pellets from press to big-bagy, kilowatt; Ckh –cost of energy
unit, €.
Useful output of biofuel is quantity of production divided by whole volume of raw
material. This characteristic is very important for evaluation of whole effectiveness of the
process of fuel production. It depends on losses volume and quantity of defective goods.
262
Crumbliness is a characteristic of final granulated product to destroy under the influence
of external factors. This characteristic is important for biofuel transporting to a consumer.
Biofuel must keep initial size and form, what is a condition of effective automation of boilers
for its firing. In other case, fuel delivery into fire chamber may be break and, as the result,
firing process is broken too. In this case, volume of heat energy, getting in a time unit, is not
stable, what can lead to irregularities in a heat supplying system.
Take into account this number of factors, influencing on technological process, is possible
only using automation control system over the granulating process. The following scheme of
automation control system over the granulating process of dispersed wood raw material into
biofuel is suggested (fig. 1).
Fig.1. Scheme of automation of technological process of granulation of reduced wood raw material.
Complex action begins from conveyor energizing, which supplies granular wood
materials into bunker. At the same time agitator, which prevents packing of supplied
material, switches on. When the bunker gets the necessary level of raw, press rolling
automatically turns on. Matrix heating occurs in several minutes. After this time passes,
automatically and sequentially electric motors of non-granulated mass blower, conveyer,
which provides transporting of hot granules into quenching chamber, chamber blower switch
on. At the same time the valve, supplying raw materials into press, opens. In dependence
with working condition, the necessary rotation frequency of screw conveyer, supplying raw
263
into press, is installed with the help of frequency regulator. For preventing fire risks,
connected with smoldering of upper layer granules at press output, an automatic matrix
temperature decreases, which heats under the influence of high pressure and friction force
between press rollers and matrix. Automation system previews constant temperature changes
of matrix during processing. If temperature override the accepted value, rotation frequency of
press rollers automatically increases, what leads to decreasing of matrix temperature. So, fire
risks in manufacturing is lowered.
Quantity of finished granules directly depends on moisture of granular wood particles,
supplying in press granulator. When this value is exceeded, finished granules have higher
index of crumbliness and looses necessary characteristics while transporting. When the
moisture contain is not sufficient, lignin, being a cohesive material, doesn’t spread uniformly
in all raw material mass and finished granules are fragile. Besides, in this case, matrix wear is
high, because of raised friction between raw and cavity. Thus, humidity detector of granular
materials is installed and according to its measurement results, water supplying into screw
chamber is regulated before pressing operation. Thus, automation system provides the best
humidity value of raw, supplying into press granulator. The system provides it in real time
mode, without suspension of production and independently of equipment functioning.
As it was mentioned above, at the press output, granules are fragile and contain large
quantity of residual moisture. Because of it they are sent to quenching chamber. When
supplied granules get the ceiling level in a bunker of quenching equipment, control signal is
given for opening of actuating mechanism, discharging cooled granules on a conveyor and
for opening screw conveyer, off taking non-granulated mass. At the same time control signal
is given to a conveyor electric motor, moving the finished granules into packing bags – bigbags.
Thus, suggested method of automation control under the process of biofuel production
from granular raw materials supports safe functioning of all equipment. Suggested system
allows to provide defined moisture of finished product, and also to exclude smoldering of
upper layer granules, what increases the quantity of biofuel. The way of automatic control
expects energy and resources saving, which are used in processing. According to preliminary
estimates, energy saving in press processing of different materials is about 20%. In a whole,
all above-mentioned advantages provide general efficiency, increase technical and
economical effectiveness of the process.
REFERENCES
1. http://biofuel.by/ru/pellets_made/ogm15.
2. Rasev, A.I. Some usage problems of wood waste materials in fuel granules
production [Text] / A.I. Rasev// BIOENERGETICS. – 2007. - 2(7). – pp.40-41.
Streszczenie: UnowoczeĞnienie aparatury do przemysáowej produkcji biopaliw. Artyku
prezentuje rozwój sstemu automatycznej kontroli produkcji, z naciskiem na popraw
technicznej i ekonomicznej wydajno ci produkcji biopaliw. Oszcz dno energii na prasie
wynios a 30-35 %. Ujmuj c ca o ciowo, wszystkie unowocze nienia daj wyniki
wystarczaj ce do zastosowania w procesie produkcyjnym.
The Dean of the faculty of wood processing technology of Voronezh State Academy of Forestry and
Technologies,
8, Timiryazeva str, Voronezh, Russia.
E-mail address: [email protected] (Andrey Safonov).
Monitoring of costs and creation of calculations in business
ANNA ŠATANOVÁ
Department of Business Economics, Technical University, Zvolen, Slovakia
Abstract: Monitoring of costs and creation of calculations in business. The aim of this paper is an application of
selected methods of cost calculations in the analyzed company. The proposals are based on calculation system of
the company; it means the used methods and types of calculations, which should contribute to more effective
monitoring and evaluation of costs. We suggest the application of the stair-step calculation of variable costs and
the calculation of costs according to activities (ABC method). Advantages and disadvantages of the selected
calculation methods will be presented in conclusion of this paper.
Keywords: variable costs, calculation, calculation methods, ABC method, business calculations, calculation
system
INTRODUCTION
Building of the well-functioning, profitable company is a very laborious and lengthy
process. The stable, successful evolution is achieved hardly, but it can be lost very easily
(Sedliaþiková, 2005). In the past in centralized economy, many of the principles of corporate
governance were implemented; covering calculations, planning, monitoring and evaluation of
deviations. In the calculations, methods and procedures based on the system of full
calculations were used; and in many companies have still been used. In the market economy,
it seems to be very important and necessary to use the methods and processes based on the
system of calculations of incomplete (variable) costs and calculations by activities that can
contribute, by significant degree, to development of the effective control-oriented
management system.
According to the conversion of pumping and recovery of the costs from the achieved price
of a performance there are distinguished: the systems of calculating with the full costs
(absorption costing) and the systems of calculating with imperfect (variable) costs
(incomplete costing). In addition to these systems of calculating, in practice, there are still
used also the others, such as the method of calculating by activities (Activity Based Costing).
The traditional system of the full calculations assigns all incurred costs (fixed + variable)
to the cost bearers. The difference between the sales and the cost is the profit. The calculation
systems which are based on a particular group of costs and do not take into account all cost
items, can be called a system of calculation of incomplete variable costs. The system of
calculation of cost based on the knowledge of variable costs (VCk) k-category of products and
the price of them (Pk). The term “COMPUT MARGIN" (CMk) is being introduced.
[€]
(1)
CMk = Pk – VCk
When the previous indicator is divided by the price per unit of production (Pk), we get the
factor of coverage, the percentage of coverage - known as PVCM). It is a relative expression
of this indicator.
In contrast with the previous methods, which assign the costs directly to the products, by
ABC methods, in the first phase, the resources are allocated to the specific activities (the
265
first allocation) and in the second phase, costs of activities are assigned to products (the
second allocation). The resources, therefore, do not enter to the product directly, but through a
very important article of activities (Figure 1).
Traditional
approach
Approach
ABC
Costs
Products
1 allocation
2 allocation
Resources
Aktivities
Products
Figure 1 The approach of traditional methods and the ABC method in assessing costs
Our task will be to compare the current system of calculating i.e. calculation of full
costs in the selected woodworking enterprise with the proposed system of calculating of
incomplete (variable) cost and with the ABC method of calculating.
In the next section, we present planned calculations for selected products in the
woodworking enterprise during the closed accounting period established in the system of
absorption calculating, respecting the structure of production and feasibility part of used
calculation formula. The data presented in Table 1 are based on documents published in
literature (Sedliaþiková, 2003) and they were modified for needs of the system of calculating
of incomplete cost.
Tab. 1 The absorption calculating in selected company
Implementation (€)
Full costs
Marketin
Products
of
Implementation
Admin. Costs outsid
Profit(+) Sales from Profitabili
g
costs
expenses the division impleme Loss (-) mplement of sales
costs
nt.
Lumber beech8 240
1 3852
95 032
-7 333
87 698
71 565 661
1 379 211
- 8,36
expedition
164
732
185
345
840
Lumber beech –
own
consumption
Sleepers
7 336
1 191
2 003
199
10 729
-4 243
6 486
-65,42
expetition
Exported beech
6 019
-2 751
3 267
blanks and
4 641 059
393 455 661 446
65 855
-82,21
847
905
942
prisms beech
Heart lumber
643 477
63 866
107 366
10 690
825 399 -441 160 384 239 -114,81
beech
Sleepers beech
Crossover beech
Sleepers
imported
Lumber poplar
Lumber
spruce/fir
Second. prisms
138 773
45 614
76 682
7 635
265 993 -152 357 113 636
-134,1
beech
Chips
8 744
14 700
102
91
Together
77 246 044
1 463 590
-11,68
10 68301
290
229
154453
471143
0
266
Based on the results of calculating of full cost, we can say that all five products made
outside the enterprise will be loss. This is due to the fact that this group of products bears the
costs incurred in marketing, administration, and disproportionately high costs formed outside
the division. Therefore it is necessary to take certain measures in this area. One of the
possibilities is to exclude the products with the lowest profitability from the production
program, eventually to increase their selling price. Another option is to seek opportunities for
savings of expected costs. The decisions taken as a result of profit per unit of production are
not, for the purpose of managing, correct and justifiable. Therefore it is necessary to establish
the calculation of incomplete costs. The complete calculation, for needs of controlling the
costs, is inappropriate because it also calculates proportionally the fixed costs into products by
the overhead charge. This fact creates an uncertainty in the distribution of costs. The
incomplete calculation is appropriate because it allows the correct planning, management and
control within the corporate planning and controlling (Table 2).
Tab. 2 The incomplete calculation per groups of products – inputs
No.
1.
2.
3.
Group of
products
Beech
Poplar
Spruce/Fir
Products
Lumber beech –
expedition
Lumber bch – own
consumption
Sleepers exported
Sleepers impregnated
Exported beech blanks and
prisms beech
Hearrt lumber beech
Secondary prisms beech
Crossover beech
Sleepers beech
Chips
Lumber poplar
Lumber spruce/fir
VC
€/m3
Production
m3
KP together
(€)
5 444,72
12 820,0
17 903 340,4
2 609,30
34 532,1
16 517 321,8
3 821,12
3 280,58
1,8
57,3
-592,5
27 011,5
8 670,21
580,0
- 1 760 783,2
7 142,00
668,39
3 748,45
3 684,68
756,18
769,91
472,55
99,4
72,4
44,4
2 263,4
15 417
12,9
40,2
-325 675,9
67 508,6
20 966,4
1 069 472,1
-2 010 020,0
6 108,1
18 978,9
KP per
groups of
products (€)
31 508 549,2
6 108,1
18 978,9
From the results of the previous table it is clear that no group of products has the total
covering contribution negative. In the group of beech products where some products have the
negative covering contribution it can be achieved the total positive covering contribution of €
31,508,549. From the production schedule is not possible to eliminate chips (despite the
negative covering contribution) because they form a starting material utilized in other areas of
the enterprise production (e.g in the production of chipboard) and they represent an efficient
use of waste in the production of other products. For other products achieving the negative
covering contribution, we accent to review the prices of products (mainly lumber and
exported blanks and prisms) once again.
Using the ABC analysis of variable costs and sales, we found that the group of product A:
beech lumber, intended both for their own consumption but also for the expedition, has the
decisive influence in the analysis of variable costs. Following is the group of products B:
chips and beech sleepers and exported beech blanks and prisms. All other products were
included in group C. The covering contribution of the product group A reaches the value €
34 420 662. The negative covering contributions of the product groups B (€ - 2 701 331,1)
and C (€ -185 694,9) is due to already mentioned group of products, but in terms of the total
covering contribution to the operation screen of the division they have no significant effect.
267
Tab. 3 The incomplete calculation per groups of products - ABC analysis
Group of
products
A
B
C
Products
Lumber bch – own
consumption
Lumber bch – expedition
Chips
Sleepers beech
Exported beech blanks
beech
Jadrové lumber beech
Sleepers impregnated
Crossover beech
Lumber spruce/fir
Secondary prisms beech
Lumber poplar
Sleepers exported
VC
together (€)
Sales
(€)
KP together
(€)
90 104 716
106 622 038
16 517 321,8
69 795 500
11 658 026
8 339 945
87 698 840
9 648 006
9 409 418
17 903 340,4
-2 010 020,0
1 069 472,1
5 028 725
4 641 059
- 1 760 783,2
709 914
187 841
166 431
110 306
48 391
9 932
7 079
384 239
214 853
187 398
129 285
115 900
16 040
6 486
-325 675,9
27 011,5
20 966,4
18 978,9
67 508,6
6 108,1
-592,5
KP per groups
of products (€)
34 420 662,2
- 2 701 331,1
- 185 694,9
The ABC method is very difficult and exacts large scale and detailed survey data. Data
volume increases with the number of assessed activities and their relationships to some part of
the sets of final products. Thus the success of the method depends on the quantification of the
share of dependent and independent costs on the volume of transferred activity. ABC analysis
can be also applied to monitor different types of fixed costs of product, group of products,
operation, division or enterprise.
CONCLUSION
The application of the selected methods of calculations of costs in the spotted enterprise is
based on the calculation system of enterprise. We propose the application of calculations of
variable costs and calculations of costs according to activities (ABC method). Also
advantages and disadvantages of application of selected methods of calculation are listed.
REFERENCES:
1. GEJDOŠ, P., POTKÁNY, M. 2003. Using ABC analysis as a basic marketing tool of
strategic controlling, In: Marketing and Trade 2003, Zvolen: TU Zvolen, 2003, p. 173176, ISBN 80-969033-0-6.
2. POTKÁNY, M. 2003. Possibilities of using incomplete calculation of costs as the
principal tool for controlling price level modeling, In: Economics and Management,
Proceedings of the International Science Conference Zvolen: TU Zvolen, 2003, p. 319
-326. ISBN 80-969031-9-5.
SEDLIA IKOVÁ, M. 2003. Creation of an incomplete calculation. Diploma thesis,
TU Zvolen DF, 2003, 74s.
3. SEDLIA IKOVÁ, M. 2005. Improving business performance through the
identification of reserves in financial management. In: Logistics-distribution systems:
an international scientific conference. Zvolen: Technical University in Zvolen, 2005,
p. 178-183, ISBN 80-228-1446-6.
ŠATANOVÁ, A. 2004. Controlling in the enterprises of the timber industry. Scientific
studies Elected: Publishing Zvolen, 2/2004/B. With 81, ISBN 80-228-1310-9.
268
Streszczenie: Monitoring kosztów i tworzenie rozliczeĔ w biznesie. Celem tej pracy by o
zastosowanie wybranych metod do analizy kosztów w przedsi biorstwie. Propozycje bazuj
na systemie ksi gowym firmy, znaczy to e u ywaj metod i typów wylicze , które powinny
przyczyni si do efektywniejszego monitorowania i oceny kosztów. Zasugerowano metod
ABC, wady i zalety tej metody s opisane we wnioskach.
prof., Ing. Anna Šatanová, CSc.
Department of Business Economics
Faculty of Wood Science and Technology
T. G. Masaryka 24
960 53 Zvolen
Slovakia
mail: [email protected]
phone: 00421-045-5206428
Shear strength of the joint wood – carbon lamella after moisture and heat
conditioning
JÁN SEDLIA IK – MÁRIA ŠMIDRIAKOVÁ
Technical University, Zvolen, Slovakia
Abstract: Application of carbon lamella on wood parts gives us the possibility to improve mechanical properties
of wood construction. Glued carbon lamella increases load capacity of wood construction and decreases
deformation. Shear strength of the joint wood – carbon lamella was tested. Glued joint was subjected to moisture
and heat stressing. One component polyurethane adhesive Jowapur 686.60 was used and glued joints were tested
according to the standards STN EN 301, STN EN 302 a STN EN 14257. Tested adhesive was suitable for gluing
of wood with carbon lamella, glued joint met the standard in the field of application number I.
Keywords: carbon lamella, gluing of wood, gluing of wood with carbon lamella, shear strength
INTRODUCTION
Wood as construction material has been used for ages. Popularity of wood
constructions has been increased also thanks to glued layered wood. Requirements for wood
construction quality are constantly increasing; longer span and load capacity of wood
construction is required. Wood historical objects need to be strengthened.
In those situations, usage of a combination of materials is very advantageous. If glued
layered wood is connected with composite materials reinforced by fibers, new materials with
improved mechanical properties are created.
Carbon fibers are characterized by high strength, modulus of elasticity, and heat
resistance, together with low weight. In layers of graphite, the atoms are bound in aromatic
rings by strong covalent bonds. The structure is available in carbon fibers; the basal aromatic
rings are oriented parallel to the longitudinal axis of a fiber. Graphite micro crystals are turned
on each other by small angles; the belt of parallel aromatic layers is slightly wavy. Graphite
fibers are made from polyacrylonitrile fibers (PAN) in three stages: stabilization,
carbonization, and graphitization (Jan á , 1999).
Carbon lamella is a composite material based on unidirectional oriented carbon fibers
linked by epoxy resin. Mechanical properties of lamella are determined by type, number, and
orientation of carbon fibers in the cross-section of lamella. If carbon fibers are oriented in the
longitudinal direction of lamella, good mechanical properties are reached; namely high tensile
strength and module of elasticity. Composite materials reinforced with carbon fibers are used
in construction industry to strengthen reinforced concrete structures.
Application of carbon lamella onto wood parts increases load capacity of the wood
construction and decreases deformation. Carbon lamellas are applied in the tensile or in the
shear part of the structure, parallel to the longitudinal direction of a beam. Carbon lamella
takes over the tensile stress, neutral axis is moved towards the glued line and wooden part of a
cross-section takes over the compressive stress. Lamellas are characterized by a multiple
higher value of tensile strength when compared with wood. When a beam is fastened with
glued lamella on tensile stress side, it can carry/suffer higher tensile stress/tension, while the
cell walls are collapsed in the compressive zone (Štefko, Grniak, 2004).
The reasons for strengthening wood constructions with carbon lamellas are:
- to increase load capacity,
- to reduce a cross-section of a beam (required by architectural design),
270
- to decrease deformation of the construction,
- to eliminate potential construction defects,
- rehabilitation and reconstruction of historic wooden constructions.
The important factor in the process of strengthening is the strength of the joint wood –
carbon lamella. Problems can be caused by shear properties on the edge of wood and
composite material, by unequal dimensional stability of wood in comparison with
dimensional stability of lamella, and by shear at moisture changing. Moisture changing in the
environment does not influence dimensions of the lamella; but wood swelling gives rise to
shear stress on the edge wood – carbon lamella. Depending on kind of wood and used
adhesive, the joint can collapse spontaneously without any external power (Tingley
and Cegelka, 1996).
Similarly, the thermal stability of glued joint is an important criterion to determine
a suitability of the adhesive in the field of new technologies and engineered wood. During
product life, glued joint can be exposed to high temperature in various ways (direct exposure
to the sun, fire, etc.). Clauß (2010) investigated different adhesive systems and the influence
of temperature (20 °C to 220 °C) on the shear strength of glued wood joints. The strength of
bonding changes under thermal load, there were big differences in thermal stability and
failure behavior between tested adhesive systems.
The strength of glued joint is closely related to the surface machining. At gluing of
carbon lamella to wood, wood surface should be machined according the standard STN 49
0231 in the level 3 (cutting – clean) and the level 5 (milling) (Rohanová, Dubovský 2004).
There is no standard method for reinforcing wood constructions; therefore we chose a
procedure according to the standards STN EN 301, STN EN 302-1 and STN EN 14257.
Test specimens for measuring of shear strength of wood – wood (BK–BK) joint were
made from beech wood (Fagus sylvatica) with density 700 kg/m3 and moisture content 12 ± 1
% according to the standard STN EN 302-1. Another set of samples were made from spruce
wood (Picea abies), marked as SM.
The shape and dimensions of test specimens for measuring of shear strength of beech
wood – carbon lamella (BK–C) and spruce wood – carbon lamella (SM–C) joints are shown
in Fig. 1.
Fig. 1. Test specimen for measuring of shear strength of wood – carbon lamella joint
We used lamella reinforced by carbon fibers in epoxy resin matrix Sika® CarboDur®
S 512 (50 mm wide and 1,2 mm thick).
271
Technical data of the Sika® CarboDur® S 512 lamella are:
- density [g/cm3]
1,6
- heat resistance [°C]
150
- fiber volume [%]
> 68
- minimal tensile strength [MPa]
> 2800
Adhesive Jowapur 686.60 is a polyurethane one-component adhesive suitable for
structural applications – wood construction for indoor and outdoor use. According to the
standard STN EN 301, according to suitability for use in climatic conditions, the adhesive is
classified as type I adhesive. Glue line with thickness of 0,1 mm was tested. Moisture content
of glued wood should not be lower than 9 %, optimal moisture content is 9 – 13 %. The
adhesive cures by a reaction with bound water of wood.
Shear strength was measured and evaluated using a tensile testing machine LaborTech
4.050 with 5 kN head. The speed of the jaws was 5 mm/min, the joint collapsed after 30 to 90
seconds. Glued joint quality is determined by the standard STN EN 301 according to the shear
strength values. Ways of specimens conditioning (from A1 to A5) before measuring of shear
strength are defined in the standard STN EN 302-1.
Heating test was carried according to the standard STN EN 14257 (WATT 91). Test
specimens were warmed in a preheated fan oven at 80 °C for 60 ± 2 minutes and then tested
to fracture in a tensile testing machine.
Average values of measured shear strength of test specimens (after preliminary
conditioning A1- A5 and after heat stressing according to WATT 91) are listed in the tables 1
and 2. We give also the view on the pattern of the break, i.e. break surface covered with wood
fibers.
Table 1. Shear strength of test specimens after preliminary conditioning (A1 – A5) according to EN 302
Method
Test
Required shear Average shear
Standard
Coefficient of
Wood failure
specimen strength [MPa] strength [MPa] deviation[MPa]
variation [%]
[%]
A1
BK–BK
10,0
1,38
9,0
98
15,3
A1
BK–C
10,0
1,90
13,6
50
14,0
A2
BK–BK
6,0
0,69
10,5
0
6,7
A2
BK–C
6,0
0,86
11,8
0
7,3
A3
BK–BK
8,0
2,19
14,1
95
15,5
A3
BK–C
8,0
1,63
10,5
37
15,5
A4
BK–BK
6,0
0,87
12,5
10
7,0
A4
BK–C
6,0
1,17
13,7
0
8,5
A5
BK–BK
8,0
2,19
16,2
10
13,5
A5
BK–C
8,0
2,98
26,8
0
11,1
Table 2. Shear strength of test specimens after heat stressing according to EN 14257 (WATT 91)
WATT 91
BK–BK
7,0
1,58
11,2
14,0
WATT 91
BK–C
7,0
1,36
14,1
9,7
WATT 91
SM–C
7,0
1,08
11,4
9,5
70
30
100
The obtained results were processed by statistical methods, by two-factor analysis of
shear strength. The differences between BK–BK shear strength and BK–C shear strength of
all samples after moisture conditioning are statistically evaluated in the Fig. 2 (95 %
confidence intervals for each preliminary conditioning method). Differences between average
shear strength of BK–BK and BK–C are statistically insignificant.
272
Fig. 2. Graph 95 % confidence intervals for each preliminary conditioning method at
measuring of shear strength of glued joint
After preliminary conditioning A2 and A4, BK–C joint shear strength was higher than
BK–BK joint shear strength. The adhesive bond BK–BK is exposed to water on both sides,
whereas the adhesive bond BK–C is exposed to water on one side only, as water can not
permeate through the carbon lamella. Surprising situation was observed at test A3, when
carbon fibers were broken. Tensile strength and module of elasticity of carbon lamella is
several times higher when compared with the strength and elasticity of beech wood. The
failure can be explained by the possibility of failure of lamella surface, if carbon fibers were
not strongly bound to the matrix epoxy resin.
In complex statistical evaluation, we can conclude that glued joints BK–BK and BK–
C are equivalent.
At heat stressing test WATT 91, the difference between shear strengths was
statistically high significant. The shear strength of BK–BK joints was much higher than the
shear strength BK–C, or SM–C respectively. Glued joint BK–BK showed higher thermal
stability; both types of joints met the required strength value above 7 MPa. The carbon
lamella, when compared to wood (following chemical structure), is less reactive with
polyurethane adhesive.
When comparing the shear strength of BK–BK and BK–C joints from the point of
view of heat stressing or moisture stressing, we can see that the shear strength of the joint
BK–C is much more influenced by heat stressing (worse strength) than by moisture stressing.
CONCLUSION
The examined adhesive meet the requirements defined by the standard for gluing of
wood load constructions; when gluing two pieces of wood together and gluing carbon
lamellas to wood.
Adhesive Jowapur 686.60 can be classified as type I proper for using at temperatures
higher than 50 °C in a climate with relative humidity more than 85 % at 20 °C. The adhesive
is applicable at outdoor conditions – at unlimited climatic influences.
273
Good adhesive properties of polyurethane adhesive result from its chemical structure;
high polarity of izokyanate group enables reacting with the functional hydroxyl groups of
wood and the epoxy resin (matrix in carbon lamella) and so creating the strong chemical
bond.
REFERENCES
1. CLAUß, S., JOSCAK, M., NIEMZ, P., 2009: Thermal stability of glued wood joints
measured by shear tests. Eur. J. Wood Prod. Published online: 05 February 2010.
2. JAN Á , J. 1999. Úvod do materiálového inženýrství kompozit . Brno: Vysoké u ení
technické Brno, 100s.
3. ROHANOVÁ, A., DUBOVSKÝ, J., 2004: Materiálové a technologické parametre pri
lepení uhlíkových lamiel na drevo. In: Zborník z odborného seminára. Zvolen: TU-DF,
2004.8s.
4. STN EN 301: 2006. Lepidlá na nosné drevené konštruk né dielce: fenoplasty
a aminoplasty. Triedenie a pevnostné požiadavky.
5. STN EN 302-1: 2005. Lepidlá na nosné drevené konštruk né dielce. Skúšobné metódy.
as 1: Stanovenie šmykovej pevnosti lepeného spoja v pozd žnom smere.
6. STN EN 14257: 2006. Lepidlá. Lepidlá na drevo. Stanovenie ahovej pevnosti
preplátovaných spojov pri zvýšenej teplote (WATT91).
7. ŠTEFKO, J., GRNIAK, M., 2004: Vystužovanie drevených prvkov uhlíkovými lamelami.
In: Uhlíkové vlákna v drevených stavebných konštrukciách. TU Zvolen, 2004, 36 s.
8. TINGLEY, D., CEGELKA, S., 1996: High strength fiber reinforced plastic reinforced
wood. In: International wood engineering conference. New Orleans, Lousiana, Anais,
1996. s. 57-64.
9. TONHAJZER, R., 2010: Pevnostné vlastnosti spoja drevo – uhlíková lamela po
vlhkostnom a teplotnom namáhaní. Diplomová práca, TU Zvolen, 68 s.
Acknowledgement
This paper was processed in the frame of the project No. 1/0565/10 as the result of
author’s research at significant help of VEGA agency, Slovakia.
Streszczenie: WytrzymaáoĞü na Ğcinanie poáączeĔ drewna i wáókna wĊglowego po
wygrzewaniu oraz nawilĪaniu. Zastosowanie laminatu z w ókien w glowych wzmacniaj cego
drewno daje mo liwo ci zwi kszenia wytrzyma o ci mechanicznej konstrukcji. Wzmocnienie
drewna nak adk z w ókien w glowych zwi ksza wytrzyma o oraz sztywno . Testowano
wytrzyma o na cinanie po cze drewna i laminatu z w ókien w glowych. U ywano
jednosk adnikowego kleju poliuretanowego Jowapur 686.60 przy procedurze testowej
zgodnej z STN EN 301, STN EN 302 oraz STN EN 14257. Testowany klej okaza si
odpowiedni do po cze drewna i laminatu w glowego, po czenia spe nia y wymogi
normatywne.
Ing. Mária Šmidriaková
T.G. Masaryka, 24
960 53 Zvolen
Slovakia
email: [email protected]
[email protected]
Analysis of the impact of the introduction of the euro in Slovak economy
MARIANA SEDLIA IKOVÁ
Abstract: By signing the Accession Treaty to the European Union (16 April 2003 in Athens), the Slovak
Republic committed itself to join the EMU and to introduce the common currency – the euro. Euro is the official
currency in16 of 27 EU countries and in six countries outside the EU. Slovakia introduced the euro on 1 January
2009. When introducing the new currency, it was the same as in other countries; to put smooth changeover and
to avoid unjustified price increases. This was reflected in the General Act, in several other laws, as well as in the
Code for the euro. Presented issues can be regarded as highly actual, and therefore the aim of this paper is the
analysis of the impact of the euro in Slovak economy.
Keywords: euro, introduction of the euro in Slovakia, financial impact of the euro in Slovakia, EU, the world
economic crisis
INTRODUCTION
The euro is the currency and monetary unit of the Euro zone, as well as third countries
involved. It is the second most important currency in the international monetary system after
the U.S. dollar. It is managed by the European Central Bank in Frankfurt.
It is the official currency in 16 of 27 EU countries and in six countries outside the EU. It is
fixed exchange rate to the euro in other five countries and two currency areas
(www.euromena.sk). Slovakia introduced euro as the 16th country on 1st January 2009. When
introducing a new currency, it was the same as in other countries; to get the smooth
changeover and to avoid unjustified price increases. This was reflected in the General Act, in
several other laws, as well as in the Code for the euro. Mandatory dual display of prices had
been introduced nearly five months before introduction of the euro and continued for one year
after its introduction; as well as regular decade monitoring of the selected types of goods by
the Statistical Office of Slovakia done from August 2008. However, the prices of some goods
and services can be increased by the conversion for the new currency (not just because of
rounding prices). This so-called changeover effect was observed in each country introducing
the euro. The aim of this paper is the analysis of the impact of the euro in Slovak economy.
Introduction of the euro caused several fears in population in Slovakia.
The Slovak public thought that the euro would be followed by increasing of prices.
Population rated the jump of prices as the biggest fear connected to the euro. In
Slovakia, as in other EU countries, the principle of free pricing is applied.
Development (growth) of prices of goods and services depends on the competition in
various segments of the consumer basket, so it didn’t lead to any unjustified prices
rises.
275
Another public fear was that the introduction of the euro causes a reduction of the
savings value of population. However, savings in the crowns were converted to the
euro by the same conversion rate as prices. An instantaneous value of savings
(incurred expenditure in Slovakia) in relation to domestic prices was not changed.
The third concern was the fear of progressive deterioration of savings due to low real
interest rate after joining the Euro zone. The real degradation of savings in Slovakia
has already been occurred in the past. It was caused by the negative real interest rates
on deposits due to the fact that the inflation rate was higher than the interest rates on
deposits offered by banks in Slovakia. Otherwise, Slovakia entered the low inflation
environment by the joining the Euro zone, but it is necessary to reflect that the
inflation rate in Slovakia is slightly higher than in euro area.
The fear of reduction of value of pensions is essentially very similar to the fear of the
reduction of savings value of population. If the introduction of the euro led to an
increase of the price level or to an increase of inflation, and income remained
unchanged (what did not happened), their real value would be reduced.
The situation is very clear by pensions that are granted after the introduction of the
euro. Real value of new pensions is based on the average real wage in the national
economy. Introduction of the euro accelerated the growth of real wages; therefore the
new pensions granted after the entry of Slovakia into the euro area are higher.
Table 1 shows the essentials positive effects (benefits) of the euro introduction in
Slovakia and the estimated impact. By processing of the analysis of the impact of the euro on
Slovak economics, we should be aware that the introduction brings many advantages, which
presents the benefit for the future development of our country, but also losses as additional
costs.
Tab. 1 Positive effects of the euro introduction in Slovakia
S.n.
1.
2.
3.
POSSITIVE EFFETS
Reduction of financial transaction costs
Reduction of administrative transaction costs
Elimination of exchange rate risk against the euro
4.
Reducing the volatility of exchange rates against
currencies of the other trading partners
5.
Reducing of the cost of capital
6.
7.
The increase of foreign trade
Increasing the level of GDP per capita (an increase of
foreign trade and foreign direct investment)
8.
9.
Increase of the foreign direct investment
Increase of the price transparency and
competitiveness
IMPACT
Savings of 0.30 % of GDP
Savings of 0.06 % of GDP
Savings by eliminating the risk of 0.02 % of GDP (range
0.01% to 0.08 % of GDP)
Reducing the overall effective volatility to 0.35 % (from
0.63 % - years: 2001 – 2005)
After the entering of the all V4 countries to the Euro zone
to 0.17%
Decline of the real interest rates for companies from
around 2 % to about 1 to 1.5 %
The increase of foreign trade by 50 %
The increase of GDP per capita between 70-20% in the
long term
The increase of GDP in annual growth of 0.7 % (range 0.4
to 1% per year)
Increasing pressure on prices and prevent their growth
Table 2 presents the strongest negatives (in the form of additional costs) of the euro
introduction in Slovakia and their estimated impact.
276
Tab. 2 Additional costs for the introduction of euro in Slovakia
S.n.
1.
ADDITIONAL COSTS
Technical and organizational costs
conversion of the currency
2.
Specific costs of banking sector
3.
The loss of independent monetary policy (the
renunciation of the instrument to reduction of
asymmetric shocks)
The possible higher inflation in the long term
4.
for
IMPACT
One-off costs amounting to 0.3 % of GDP
Costs associated with the task of ensuring free conversion of
local currency to the euro and a decrease of activities and
income of banks
The value of the loss of independent monetary policy is
evaluated scored around 0,4 % of GDP
Additional contribution to inflation compared to the euro
zone average amounting to 1.5 p. b. per annum
Slovakia was hit by the global crisis just before entering the Euro zone. Those few
months between the announcement and actual introduction of the euro has been proved
extremely advantageous, as compared to neighboring states that still pay their own money, as
well as to those that already have the euro. Thus, while Slovakia is not immune against the
global problems, the impact of the crisis has not caused such great shocks for Slovak
economy, as in other countries, whether in Euro zone or in the V4 countries. This is a
consequence of the fact that the Slovak currency acted as if it had been the euro in the last
weeks and months prior to the euro introduction. The upcoming acceptance of the euro has
protected us against the turbulences at financial markets. This is confirmed by the
development of the exchange rate against other currencies in the region and also the
development of long-term interest rates. According to the estimates of analysts, in the event
that Slovakia did not have fixed exchange rate, the euro would be sold by six crowns more
expensively than in that time. Such a fall of currency during the global crisis would multiply
its effects and consequences. From the presented results that Slovakia, among the
neighboring countries, best resists the global economic and financial crisis.
It is undeniable that the economic crisis temporarily reduces the benefits of the euro
in Slovakia. But analysts predict that the benefits of the new currency will more reflect when
the economic situation in other countries revives again. Global economic crisis delayed the
expected positive effects of introduction of the new European currency in Slovakia. Analysts
agree that the euro is clearly positive during the declining foreign demand. Although the
volume of foreign trade is declining and the foreign companies are cautious in investments; in
the short term, the financial crisis may slow some of the beneficial effects of the euro. On the
other hand, the economic environment in Slovakia is more stable and predictable due to the
entering the Euro zone, in comparison with neighboring countries. Advantages of the new
currency for companies would be reflected again more markedly in the payment system, when
the economic situation revives. Slovakia became a member of the Euro zone, when the
financial crisis had fully hit the real economy of many countries. The main negative
consequence of the crisis is a decrease of foreign demand for Slovak products, which will
affect the overall level of production in Slovak economy this year, too. The introduction of
euro in Slovakia eliminated foreign exchange costs, transaction costs, as well as various
administrative costs. From the presented eliminations it is possible to expect the better
connection between Slovak market and the other European Union markets. Thanks to the
Euro, Slovakia has a mainly advantage in eliminating of the exchange rate risk in comparison
with the surrounding countries that use their own national currencies. The high volatility of
currencies in neighboring countries may be a particular symbol of instability and a negative in
eyes of investors when deciding to entry into the specific country. Significant fluctuations in
exchange rates, which the central neighboring European markets are faced, increase the price
of ensuring the exchange of export revenues and remind potential investors, but also the
277
multinational companies, the vulnerability in times of global market turbulence. Not so much
domestic but external negative factors are the reason of the main weakening of the
neighboring currencies.
CONCLUSION
In conclusion, we must not forget that the export-oriented Slovak economy is mainly
focused on the markets of the European Union. Up to 86% of Slovak exports aim at Member
States and more than 50% directly to countries paying the unified currency euro. Euro is
therefore expressly good news for Slovak exports and it provides the Slovak Republic also the
stability of the euro zone domestic market from 1st January 2009. For multinational concerns
from Germany or France, the investment in Slovakia is not the foreign investment in the strict
sense - although it is a cross-border investment, but in the home market area. Although the
year 2010 will be a loading test also for Slovakia, Slovakia is prepared a little better in
comparison with its neighbors; thanks to the acceptance of the euro.
Acknowledgement
This paper was processed in the frame of the project No. 1/0517/09 as the result of
author’s research at significant help of VEGA agency, Slovakia.
REFERENCES:
1. http://www.euromena.sk/aktuality/12018c
2. http://www.euromena.sk/aktuality-stabilita-eura-je-podla-nemcov-bez-dodrziavaniapravidiel-ohrozena/1611s12064c?stxt=&sekcia=&oblast= &sfrom=&sto=&page=1
3. http://www.nbs.sk/sk/euro/zavedenie-eura
4. http://www.euromena.sk/aktuality/10298c
5. http://ekonomika.etrend.sk/ekonomika-slovensko/euro-nemohlo-prist-v-lepsomcase.html
6. http://ekonomika.etrend.sk/ekonomika-slovensko/sramko-euro-uz-tlmi-dopad-krizyna-slovensku.html
7. http://www.euromena.sk/pripadove-studie/1564s
8. http://www.euromena.sk/vplyv-zavedenia-eura-na-podnikatelsky-sektor/1556s
9. http://www.financnik.sk/financie.php?did=54&messagefr=SK&messageid=748059&
messagetitle=EURO%3A+Ekonomick%E1+kr%EDza+do%E8asne+zmierni+pozit%E
Dva+eura+na+Slovensku&date=20090127154700&lid=80&page_messages=&catego
ry=&which=SK&dt=2009012720090127&text=&kriza
278
Streszczenie: Analiza wpáywu wprowadzenia euro na ekonomiĊ sáowacką. Poprzez
podpisanie traktatu o akcesji do unii europejskiej (16 kwietnia 2003 w Atenach), S owacja
zobowi za a si do przyst pienia do unii monetarnej i wprowadzenia wspólnej waluty- euro.
Euro jest oficjaln walut w 16 z 27 krajów cz onkowskich. S owacja wprowadzi a euro 1
stycznia 2009, w podobny sposób jak w innych krajach, w sposób agodny zapobiegaj c
nieuzasadnionemu wzrostowi cen. Celem artyku u jest analiza wp ywu wprowadzenia euro na
ekonomi S owacji.
Ing. Mariana Sedlia iková, PhD.
T. G. Masaryka 24
960 53 Zvolen
Slovakia
phone: 00421-045-5206420
Whitening of oak wood with hydrogen peroxide
S. SEMAK, P. MA KOWSKI, A. MAZUREK
Faculty of Wood Technology WULS Warsaw
Abstract : Whitening of oak wood with hydrogen peroxide. Whitening of oak wood with hydrogen peroxide was
tested. Different concentration of hydrogen peroxide were used. Samples were soaked for: 5min, 15min, 30min,
1h, 6h, 12h, 24h, 168h (7 days). After drying color was determined. Basing on the obtained results, brightness,
hue and saturation changes were calculated.
Keywords: oak, hydrogen peroxide, X-Rite
INTRODUCTION
Every wood species has its natural color. Wood can be tinted in many hues, from
white thru yellow, red, brown to black. Coreless species are bright on whole section, core
species have distinct darker colors of heartwood from bright sapwood. Color of core species
may cover whole spectrum, depending on quantity of non-structural substances. These
substances include dyes, tanning agents and gums [Krzysik 1978].
Wood color is mostly dependent on the species, but is also influenced by climate and
environmental conditions [Krzysik 1978]. Oak wood, in dependence on the environment may
have colors ranging from beige to black [Pra mo 1968].
After tree falling, wood changes its color under influence of light, fungi and chemical
substances present [Szczuka 1970].
Considering domestic species, they may be divided into color groups such as: whitish
(fir, spruce, aspen, hornbeam, beech, maple, great maple), yellowish (birch, Swiss stone pine),
reddish (yew, larch, pine, cherry, plum), brownish (oak, ash, elm), or close to black (walnut)
[Krzysik 1978].
Whitening of wood is applied in aim to remove stains or discolorations forming due to
improper storing and to simply unify color. Hydrogen peroxide is most common whitening
agent used for oak wood. Oxalic acid, citric acid, calcium hypochlorite, potassium oxalate and
sodium sulfate are also being used.
METHODIC
Oak samples of 30x50x5 mm dimensions were prepared for tests. Each sample was
tested with X-Rite model SP 60 spectrophotometer. Measurement area for each sample was
defined (8mm circle for spectrophotometer). Measured samples were arranged into packets
allowing easy hydrogen peroxide penetration into material’s faces (Fig.1.). Packets were
tightened with white thread, preventing falling apart and put into seven containers filled with
different hydrogen peroxide solution of different concentration. samples were loaded with
glass plugs, in aim to keep them submerged. Containers were tightened and placed in the
dark, remaining three samples were treated as a reference.
280
Fig. 1. Packet of samples used in the experiment.
Following concentration of hydrogen peroxide were used: 2%, 5%, 10%, 15%, 20%, 25%,
and 30%.
Samples were soaked for: 5min, 15min, 30min, 1h, 6h, 12h, 24h, 168h (7 days).
After each stage packets were removed, soaked and left for drying in the dark place. After
drying color was determined, using the same spot as before procedure. Basing on the obtained
results, brightness, hue and saturation changes were calculated.
RESULTS
Zmiana jasnoĞci
.
Application of hydrogen peroxide on oak wood causes brightening of the material. It
was determined that solution strength and extended time causes brighter wood color (Fig. 2.).
In the initial whitening stages colors of the samples are very diversified, probably as a
result of different dye and tannin washing from the internal parts of wood [Tyszka 1987], and
their settling on the tested surfaces.
Quickest color change occurs during first hour of treatment, in this time happens 40% of
whole change of 7 days soaking. After that discoloration occurs at much slower ratio.
Highest brightness change occurs after week of treatment, and equals 14,04 [Semak
2009].
14
12
10
8
6
4
2
0
0
24
48
72
96
120
144
168
Czas dziaáania H2O2 na próbki [h]
2%
5%
10%
15%
20%
25%
30%
Fig. 2. Changes
of brightness in whitened samples.
Sample pictures of natural and whitened oak wood are presented on figure 3.
281
Fig. 3. Sample color change. Oak wood before and after 7 days treatment with hydrogen peroxide.
CONCLUSION
1. Application of hydrogen peroxide on oak wood causes its brightening.
2. Greatest brightness change of oak wood occurs during first hour of soaking in hydrogen
peroxide solution.
3. Brightening effect is proportional to strength of hydrogen peroxide solution.
4. Extending soaking time of oak wood in hydrogen peroxide solution increases brightening
effect.
REFERENCES
1. J. VAN DER GEER, J.A.J. HANRAADS, R.A. LUPTON, The art of writing a
scientific article, J. Sci. Commun. 163 (2000) 51–59.
2. F. KRZYSIK , Nauka o drewnie. PWN, Warszawa 1978,
3. J. TYSZKA, Powierzchniowe uszlachetnianie wyrobów z drewna. WN-T, Warszawa
1987
4. J. PRA MO, Stolarstwo cz.1. WSiP, Warszawa 1999,
5. J. SZCZUKA, Materia oznawstwo przemys u drzewnego. WSiP, Warszawa 1970,
6. S. SEMAK, Ocena skuteczno ci bielenia drewna d bowego przy u yciu nadtlenku
wodoru, 2009
Streszczenie: Bielenie drewna dĊbu nadtlenkiem wodoru. W artykule przedstawiono wyniki
bada bielenia drewna d bowego przy u yciu nadtlenku wodoru. Zastosowano ró ne st enia
roztworu i ró ny czas moczenie drewna. Zmiany koloru rejestrowano spektrofotometrem
sferycznym X-Rite.
Piotr Ma kowski
[email protected]
(Ann. WULS–SGGW, For.and Wood Technol. 72, 2010)
ɉɪɨɱɧɨɫɬɧɨɣ ɪɚɫɱɟɬ ɮɥɹɧɰɟɜɨɝɨ ɡɚɯɜɚɬɚ ɤɪɭɝɥɨɣ ɩɢɥɵ
1
1
,
1
2
,
,
2
,
–
–
,
,
Abstract: Strength dimensioning of flange joint of circular saw device. methodology of strength dimensioning
of flange joint of a circular saw device of cutting mechanism is presented in this work. Strength and validating
calculations of the elements of the flange joint of the circular saw device are carried out. They include the
diameter of the shaft and its thread, the dimensions of the flanges with a view of the firm grip of the circular saw
device, the height of the nut and its self-locking thread.
Key words: circular, cutting mechanism, flange joint, flange, circular saw device, nut height, self-locking thread
,
. .
,
,
.
.
,
,
-
,
.
,
.
,
.
.
,
ó
,
.
,
.
,
,
.
.
1m
.
.1.
.
,
, . .
M TP t M P ,
M TP –
MP –
(1)
, N.m;
, N.m.
283
0,5 F1 D ,
MP
F1 –
D–
(2)
, N;
, m.
dM TP
dM TP
2dFTP rx ,
dFTP -
,
drx
(
.1), N; rx –
, m.
Q,
FTP (
,
.1).
r2
,
r1
,
q (
)
.
r
q
Q
,
r22
2
1
Q-
(3)
,
,
, N;
(
Ɋɢɫ. 1.
r1, r2 –
.1), m.
(
dFTP
dFTP
2
qrx drx ,
.1)
-
.
dM TP
dM TP
4
qrx2 drx
.
r1
r1 ,
r2
M TP
4
q ³ rx2 drx
r2
q
4
q
r13 r23
.
3
(3),
M TP
4 Q r13 r23
.
3 r12 r22
M TP
(4)
Q
«
,
–
AQ AF* AF
,
–
» [1]:
,
(5)
AQ -
Q
AQ QP
,
;
p
284
Ɋ–
( .1), m;
– . . .
;
A F* F
AF* 2 Q r0 ;
,
–
r0 –
d –
r0 = 1,35d,
[2];
A F Ⱥ( F ) 2 F L .
,
F –
L–
, m.
L = 13d [2].
;
(
.1), m.
,
F
,
, N;
(5),
QP
2SQ r0
L,
2 F
(6)
p
(6)
Q
2 .F
P 2
LK p
r0
p
Q
.
(7)
Q
(7)
(4),
Ɇ
M TP
8
F
r12
3
3
p r1
L
r22
P 2
r23
r0
p
,
(8)
M TP
(2)
MP
(1),
:
8 F
r
2
1
L
r
3
p 1
r22 P 2
r23
r0
p
(8)
0,5 F1 D ,
F1,
F1
= 0,5
Q
F1
16 F
D
r12
L
r22
P 2
= 0,12,
2 F
P 2
D
r12
3
p r1
Q
L
r0
r23
r0
p
(7)
F1
,
.
(9)
(9)
:F
314.L
p
,
P 0,377r0 p
95.L r13 r23
r22 P 0,377r0 = 100 N,
(10)
0,3Q r13 r23
.
D r12 r22
285
(11)
(11)
F1
Ɋ1
'
F1 ,
:
F1
P1
'
,
(12)
. .
F1 > F1
'
(13)
(10)
Q
.
d ,
(
.1).
d2
d1
d,
Ɋ
,
.
,
.
,
,
[2]
d
H
2
4Q.P
d12 >
CM
@
,
(14)
, m;
ɇ [ CM] [ CM] = 30 MPa.
, MPa.
45
[2]
5,2Q
d1
>
@
,
(15)
d1 –
[ ] –
, m;
, MPa.
[
45
] = 90 MPa.
[2]
d ,
(16)
. .
,
:
arctg
d2 –
Ɋ –
-
P
,
d2
(17)
, °;
, m;
, m;
.
(16)
= 5°.
,
.
286
: 4000, 5500
7500 W.
. 1.
1.
P1,
W
D,
m
ȣ,
m.s -1
dC,
m
r1 ,
m
r2 ,
m
4000
5500
7500
0,30
0,35
0,40
45,2
52,8
60,0
0,20
0,25
0,30
0,050
0,055
0,060
0,040
0,045
0,050
r0 ,
m
d, m
0,020
0,027
0,032
0,016
0,020
0,024
d1 , m
0,0143
0,0183
0,0218
d2, m
P, m
0,015
0,019
0,0227
0,0015
0,0015
0,0020
1.
L,
m
Q,
N
F1,
N
F1' ,
N
0,21
0,26
0,31
6860
7040
7250
415
450
540
90
105
125
H ,m
0,0086
0,0090
0,0092
\R
d1, m
0,013
0,017
0,020
0,0113
0,0115
0,0117
0,0143
0,0183
0,0218
1,84
1,60
2, 0
,
5
5
5
,
-
.
Acknowledgement: This work was supported by the Scientific Research Sector of the
University of Forestry, Sofia - project 46 / 2009.
1.
. ., . .
,
2.
, 1973:
.
, ., 2007:
,
.
.
-
.
Streszczenie: Projektowanie koánierzy zacskowych piáy tarczowej. Artyku prezentuje
metodyk wyliczania wymiarów ko nierzy zaciskowych pi tarczowych. Dokonano oblicze
wytrzyma o ciowych, bior cych pod uwag
rednic wa u, typ gwintu oraz wymiary
ko nierzy oraz nakr tki zaciskaj cej.
Slavcho Sokolovski, Faculty of Forest Industry, University of Forestry,
Kliment Ohridski Bd. 10, 1756 Sofia, BULGARIA, [email protected]
Nencho Deliiski, Faculty of Forest Industry, University of Forestry,
Kliment Ohridski Bd. 10, 1756 Sofia, BULGARIA, [email protected]
Ladislav Dzurenda, Faculty of Wood Technology, Technical University of Zvolen,
T.G.Masarika 24, 96053 Zvolen, SLOVAKIA, [email protected]
Strength properties change in birch veneered high density fiberboard
ANDRZEJ STARECKI1), MAREK JAB O SKI1), ANNA DANIHELOVÁ2)
EVA RUŽINSKÁ3)
1)
Faculty of Wood Technology, Warsaw University of Life Sciences – SGGW
Faculty of Wood Sciences and Technology, Technical Unversity in Zvolen, Slovakia
3)
Department of Environmental Technology, Faculty of Environmental and Manufacturing Technology,
2)
Abstract: Strength properties change in birch veneered high density fiberboard. Research consists of modulus
of elasticity and static bending strength of high density fiberboard veneered with birch at both sides. urea
formaldehyde resin was used for gluing, at 120, 160 i 200 g/m2 loads at back side of the board, and at 120 g/m2
on front side of the board. Bending strength and modulus of elasticity were tested with testing machine on both
sides. It was concluded that veneering boards with birch increases its mechanical properties, increase of back
side glue load from 120 to 200 g/cm2 increases strength of the composite.
Key words: composites, veneers, fiberboards, static bending strength, modulus of elasticity in static bending.
INTRODUCTION
Wood composite boards can be produced by combination of various wood materials
(boards, veneers) or by combination of wood or wood-based materials with non-wood
elements, such as boards, films, plastics, metal sheet and forms or ceramic products. These
are multilayer complex materials and are being produced in accordance to special orders.
Contemporary material base enables production of composite materials in practically
unlimited variants, obtaining light, strong, technologically and aesthetically good products.
Objective of the work was to determine mechanical properties (modulus of elasticity
and static bending strength) of the boards made with high density fiberboard veneered with
birch wood.
METHODIC
Three-ply composite boards were made, basing on the high density fiberboard of 3,2
mm thickness and 900 kg/m3 density, with 1.5 mm birch veneer layers on both sides. Ureaformaldehyde Silekol M 2 resin was used, prepared in accordance to producer’s suggestions.
Composite after pressing was seasoned for 2 weeks in normal conditions and then cut into test
samples.
Three variant with variable glue load on the back side were made, on the front side
single load was used - 120 g/m2. Fiberboard was pressed both sides with veneer of parallel
grain direction, gluing variant were as follows:
1. Back and front side at 120g/m2 glue load.
2. Back side at 160g/m2, front side at 120g/m2 glue load.
3. Back side at 200g/m2, front side at 120g/m2 glue load.
Packets were pressed in 125o C, during 5 min. at pressure of 2 MPa. Every board was
cut into 150 x 50 mm strength test samples. Each samples group was randomly divided into
10 pieces of back side up and 10 pieces of front side up sets. Strength and modulus of
elasticity tests were performed in ten times in both groups, frond side up and back side up.
Veneer grain direction was parallel to sample length in each case. The same tests were made
288
with regular high density fiberboard same dimensions, for comparison reasons. Determination
of modulus of elasticity and bending strength was made in accordance with PN – EN 310
standard.
TEST RESULTS AND ANALYSIS
Test results are presented on figures 1 and 2 and tables 1 and 2.
110,00
107,20 108,10
103,20
2
Static bending strength [N/mm ]
120
113,80
98,40
100
80
60
45,10
48,00
40
20
0
Regular fiberboard
Fiberboard birch veneered
at both sides,at 120g/m2
glue load
at both sides, front side
at 120g/m2 and back side
at 200g/m2 glue load
Load at front side of the board
Load at back side of the board
Fig. 1 Comparison of bending strength of regular fiberboards with fiberboards birch veneered at both sides with
variable urea-formaldehyde glue load.
Table 1. Standard deviation and variation coefficient of bending strength of 3.2 mm high density fiberboard
reinforced with 1.2 mm birch veneers at both sides.
Standard deviation S [N/mm2] and variation coefficient V [ % ] in static bending
at both sides, at 120g/m2
glue load
Regular fiberboard
Load at
front side
of the
board
Load at
back side
of the
board
Load at
front side
of the
board
Load at
back side
of the
board
at both sides, front side at
120g/m2 and back side at
160g/m2 glue load
Load at
Load at
back side
front side
of the
of the
board
board
at both sides, front side at
120g/m2 and back side at
200g/m2 glue load
Load at
Load at
back side
front side
of the
of the
board
board
S
V
S
V
S
V
S
V
S
V
S
V
S
V
S
V
1,70
3,8
2,55
5,3
8,90
9,0
9,97
8,7
6,68
6,2
5,33
4,9
7,99
7,3
9,72
8,5
289
Regular fiberboard
at both sides,at 120g/m2
glue load
Load at front side of the board
Load at back side of the board
Fig. 2 Comparison of modulus of elasticity of regular fiberboards with fiberboards birch veneered at both sides
with variable urea-formaldehyde glue load.
Table 2. Standard deviation and variation coefficient of static bending modulus of elasticity of 3.2 mm high
density fiberboard reinforced with 1.2 mm birch veneers at both sides.
Standard deviation S [N/mm2]and variation coefficient V [ % ] of static bending modulus of
elasticity
Fiberboard birch
veneered at both sides, at
120g/m2 glue load
Regular fiberboard
Fiberboard birch
veneered at both sides,
front side at 120g/m2 and
back side at 160g/m2 glue
load
Load at
Load at
back side
front side
of the
of the
board
board
Fiberboard birch
veneered at both sides,
front side at 120g/m2 and
back side at 200g/m2 glue
load
Load at
Load at
back side
front side
of the
of the
board
board
Load at
front side
of the
board
Load at
back side
of the
board
Load at
front side
of the
board
Load at
back side
of the
board
S
V
S
V
S
V
S
V
S
V
S
V
S
V
S
V
159
4,4
186
5,1
285
3,3
339
3,9
580
6,7
542
5,9
575
5,9
480
4,8
Average bending strength of regular samples loaded from front side reached N/mm2
and was lower than bending strength wit load at back side, which reached 48,00 N/mm2.
Average modulus of elasticity of regular samples loaded at front side equaled 3640
N/mm2 and was practically identical with samples loaded from the back side (3630 N/mm2).
Birch veneered boards showed higher values of bending strength and modulus of
elasticity in all variants in comparison to regular samples, in both front side and back side
loads. Strength increase depended on the glue load used during veneering. Birch veneering
with glue load of 120 g/m2 on both sides increased bending strength by 118% with front side
load, and by 115% with back side load in comparison with control samples. Application of
120 g/m2 glue load for front sides and 160 g/m2 and 200 g/m2 for back sides increases
290
strength by 138% and 144% for front side load and by 125% and 137% for back side load
respectively, in comparison to control samples.
Average modulus of elasticity values similarly as strength values increased with back
side glue load increase. For front side loaded boards of 120 g/m2 glue load modulae of
elasticity increased by 137%, back side loaded boards increased by 141% in comparison to
control samples. Application of higher glue loads for back sides of 160 and 200 g/m2,
increased modulus of elasticity for front side load by 139% and 170%, for back side load by
153% and 178% respectively, in comparison to control samples.
Variation coefficients presented in tables 1 and 2 show high concentration around
average values for all variants tested.
Strength gain noticed for the veneered fiberboard with increase of back side glue load
can be explained by increased amount of glue filling the grid at the fiberboard’s back turns
into composite of wood fibers and glue mass. Grid becomes a matrix filled with resin and
becoming a composite similar to laminate.
CONCLUSION
Results combined with the statistical calculation allow to conclude:
1. Veneering of 3,2 mm high density fiberboard with 1,5 mm birch veneer increases
static bending strength and modulus of elasticity with static bending.
2. Increased glue load from120 g/m2 up to 200 g/m2 on back side of the board being
composite’s core, increases static bending strength and modulus of elasticity in static
bending.
3. Change of fiberboard’s back side glue load from 120 g/m2 up to 160 g/m2 does not
give significant increase on strength properties in most cases.
REFERENCES
1. DROUET T. i in., 1994: „Technologia tworzyw drzewnych”, Wydawnictwo Szkolne i
Pedagogiczne, Warszawa.
2. JAB O SKI M., STARECKI A., 2000: „P yty tekturowo-fornirowe". III
International Symposium Wood Agglomeration - Zvolen, June, 28 - 30. 2000, s.247 249.
3. NICEWICZ D., : 2006: „P yty pil niowe MDF”. Wydawnictwo SGGW.
4. OKTABA W., 2000: „Metody statystyki matematycznej w do wiadczalnictwie”.
Wydawnictwo Akademii Rolniczej, Lublin.
5. PARCZEWSKI A., 1969: „Technologia produkcji sklejek”. Pa stwowe
Wydawnictwo Rolnicze i Le ne, Warszawa.
6. STARECKI A., JAB O SKI M., 1993: „Tworzywa kompozytowe na bazie forniru i
modyfikowanych materia ów w óknistych". Modyfikacja drewna ,93, s.231-235.
7. STARECKI A., JAB O SKI M., 1998: „Selected properties of plywood with fibrons
midle layer". II Mi dzynarodowe Sympozjum. Zvolen 9-10 wrze nia 1998r., s. 281284.
8. STARECKI A., JAB O SKI M., 1998: „Influence of laminating the surface of
plywood on its mechanical properties”. II Mi dzynarodowe Sympozjum, Zvolen 9-10
wrze nia 1998r., s.285-290.
9. WIETLICZNY M., JAB O SKI M., 1985: „Zastosowanie w ókna szklanego do
wzmacniania drewna". Materia y na V Sympozjum "Modyfikacja drewna", Pozna .
10. WIETLICZNY M., JAB O SKI M., TOMUSIAK A., 1987: „Próba zwi kszenia
wytrzyma o ci drewna na zginanie statyczne". Przemys Drzewny nr 6/87.
11. ZIELENICA J., 1998: „Wytrzyma o
materia ów”. Wydawnictwo Politechniki
Pozna skiej.
291
12. PN – EN 310 P yty drewnopochodne „Oznaczanie modu u spr ysto ci przy zginaniu
i wytrzyma o ci na zginanie”.
Streszczenie: Zmiany wybranych wáaĞciwoĞci wytrzymaáoĞciowych páyt pilĞniowych
twardych oklejonych áuszczką brzozową. W ramach bada wykonano oznaczenia modu u
spr ysto ci i wytrzyma o ci na zginanie statyczne p yty pil niowej twardej oklejonej z obu
stron uszczk brzozow . Do klejenia u yto masy klejowej sporz dzonej z ywicy
mocznikowo-formaldehydowej, któr nanoszono na lew stron p yty (kratk ) w ilo ci 120,
160 i 200 g/m2 oraz na praw stron p yty pil niowej w ilo ci 120 g/m2 we wszystkich
wariantach. Zginanie statyczne i modu spr ysto ci przy zginaniu statycznym
przeprowadzano przy dzia aniu napory maszyny wytrzyma o ciowej na praw i lew stron
p yty. Stwierdzono, e oklejenie p yty pil niowej twardej ob ogiem brzozowym zwi ksza jej
w a ciwo ci wytrzyma o ciowe. Wzrost naniesienia masy klejowej na lew stron p yty ze
120 do 200 g/cm2 powodowa równie wzrost badanych parametrów wytrzyma o ciowych.
Andrzej Starecki, Marek Jab o ski,
02-776 Warsaw,
Poland
Anna Danihelová,
Faculty of Wood Research and Technology,
Department of Physics, Electrotechnics and Applied Mechanics,
Eva Ružinská,
Department of Environmental Technology
Annals of Warsaw University of Life Science SGGW
Forestry and Wood Technology No 72, 2010; 293-297
(Ann. WULSSGGW, For and Wood Technol. 72, 2010)
Shear strength of glue joints of PVAC adhesives and selected wood species
EWA SUDO . PAWE SULIK
Department of Structures and Building Elements, Building Research Institute ITB
Abstract: Shear strength of glue joints of PVAC adhesives and selected wood species. The article presents the
test results of glue joints made of two components (catalyzed with polyisocyanate and Al(NO3)3) PVAC
adhesives and selected wood species: sapeli, sipo, eucalyptus and white meranti, in the conditions water and
thermal resistance tests.
Keywords: glue joint, PVAC adhesive, laminated wood, exotic wood species, window, adhesion
INTRODUCTION
Wooden windows, some say, have been enjoying a revival recently. This renewed interest,
however, entails higher expectations and requirements. Buyers expect that the windows will
have not only good functional and operational properties, high thermal and sound insulation
and strength but also unique esthetic value. To meet those requirements, wooden window
manufacturers apply non-standard solutions, including new materials. Apart from windows
made of locally growing trees – pine or oak – they also offer windows made of exotic wood.
So far, only products made of Asian wood red meranti, a mahogany-colored wood with
interesting surface texture, have been manufactured on an industrial scale.
The addition of exotic wood windows to the offer is also justified by the fact that this type of
wood has been successfully used in building industry for years, e.g. for wood flooring and
floorboards, stairs or internal doors. It must be noted, however, that all of the above are indoor
elements. Wood for the manufacture of windows – elements directly exposed to the effects of
weather – calls for special consideration.
Structural elements of modern windows, given the possibility to use different range of wood
and improvement of dimensional stability, are made of glued laminated wood. Introduction of
new wood species requires a detailed analysis of the gluability. Non-European wood species
contain a lot of side components like resins, essential oils, waxes, fats, tannins, protein
substances etc., whose varied and complex chemical composition adversely affects the gluing
process. Those components usually hinder wettability of the glued surfaces or inhibit
solidification of adhesives (Proszyk i Przybylak 1986). Interferences of the gluing processes,
caused by the presence of side components, have been thoroughly described in the relevant
literature on poly-condensation adhesives UF, PF, MUF (Hwang G., Tang J. Noguchi M.
1993). However, the scant literature on the gluability of exotic wood with PVAC adhesives
commonly used in window manufacturing indicates that the strength and resistance of the
glue joints is varied and contingent on the wood species and type of adhesive (Krystofiak,
Proszyk i Dobrowolski 1997, Sudo 2007). Some research has shown that glue joints have low
resistance to temperature and humidity in the context of using glued laminated elements in
windows (Sudo 2007).
293
EXPERIMENT
The following wood species have been selected (based on an extensive consultations with
manufactures) for the study of glue joints – names and codes according to the PN EN 13556:
African Mahogany Sapeli (Entandrophragma cylindricum Sprague), code ENCY,
African Mahogany Sipo (Entandrophragma utile Sprague), code ENUT,
Eucalyptus (Eucalyptus grandis), not included in PN EN 13556,
White Meranti (Shorea spp. section Anthoshorea), code SHWM.
The wood of all species was of J2 quality class as indicated in the PNEN 942:2008; had
humidity of 9y13% and a mean density of 710 kg/m3 (sapeli), 740 kg/m3 (sipo), 540 kg/m3
(eucalyptus), 395 kg/m3 (white meranti).
Out of the range of adhesives for window joinery, new generation PVAC adhesives were
selected:
two-component PVAC glue with 5% addition of hardener Al(NO3)3 (2K PVAC+
Al(NO3)3),
two-component PVAC glue with 15% addition of polyisocyanate hardener (2K
PVAC+EPI),
Basic properties of adhesives components are shown in Table 1, based on the manufacturer’s
data sheets.
Table 1. Properties of adhesives components used in the study
Type of adhesive
Property,
2K PVAC+Al(NO3)3
2K PVAC+EPI
Type of component
dispersion
unit
hardener Al(NO3)3 dispersion PVAC
hardener EPI
PVAC
3
Density , g/cm
1,06
1,25
1,5
1,25
Brookfield viscosity, mPas
9000
No data
11 000
300
Solid kontent, %
51
62
60
NCO content, %
31
pH
5
1
7
No data
All adhesives were classified as corresponding to the durability class D4 according to the
PNEN 204:2002 and resistant to temp. of 80qC in the study according to the PNEN
14257:2007.
Preparation of laminated elements (semi-finished products) was done in industrial conditions.
Wood in the form of lamellae 86 x 20 mm in cross-section and 1000y1200 mm in length
underwent planning. Immediately afterwards, the gluing process was conducted using
technology applied in the everyday manufacturing practice, including guidelines of the
producer of the adhesive. Basic parameters of gluing are shown in Table 2.
Table 2. Basic gluing parameters
Parameter, unit
Value
Application method
roller, one-sided
Amount of application, g/m2
165
Pressing pressure, MPa
0,6
Pressing time, min.
75
From the laminated elements thus manufactured, samples for study were obtained as indicated
in guidelines of the PNB03156:1997.
The study included the determination of strength and resistance of glue joints according to the
PNB03156:1997. Shear strength in compression was studied, after seasoning the samples
294
in conditions compliant with ITB guidelines included in the UA GS III.11/2003 concerning
the required properties of semi-finished products of glued laminated wood, used for
production of outdoor construction joinery. They constituted, during the window approval
procedures, the basis for evaluation of the usefulness of gluelam elements. Those conditions,
along with relevant requirements, are presented in Table 3.
Table 3. Requirements for shear strength of glued joints in pine-made elements,
used for window production, according to UA GS III.11/2003
Seasoning conditions
Shear strength, MPa
7 days in normal climate
t 9,0
7 days in normal climate and 4 days in water of T 20r2qC
t 3,2
7 days in normal climate and 3h in T 80r2qC
t 5,0
RESULTS
Diagrams 1 3 show the obtained results (mean values).
Diagram 1. Shear strength of glue joints after seasoning in a normal climate.
Diagram 2. Shear strength of glue joints
after seasoning in a normal climate and 4 days in water of temp. 20r2qC
295
Diagram 3. Shear strength of glue joints
after seasoning in a normal climate and 3h in temp. 80r2qC
CONCLUSIONS
Results analysis confirms the strong dependency of the joint strength on the wood species.
Glue joints, made with the same adhesive, in the same technological regime, of elements of
different wood species, show different resistance to water and high temperature.
It must also be noted that, based on the conditions listed in Table 3, only glue joints with
PVAC adhesive with polyisocyanate hardener (excluding elements made of white meranti)
and joints in eucalyptus-made elements, made with the use of PVAC adhesive with Al(NO3)3
hardener can be considered as appropriate for window joinery.
The above statement should be treated as a tentative conclusion. The final evaluation of the
solutions will include the results of other studies on glued joints (conducted according to the
guidelines FprCEN/TS 13307 2:2009 Timber blanks and semiífinished profiles for
nonístructural uses. Part 2: Production control.
The results presented here are part of the research on the usefulness of selected exotic wood
species for production of windows, conducted within the development project NR04 001 06.
REFERENCES
1. Hwang G., Tang J. Noguchi M.: Gluing Properties of HighDensity Hardwoods; Makuzai
Gakkaishi, nr (39) 3/1993, 363y367;
2. Krystofiak T., Proszyk S., Dobrowolski J., 1997: Badania sklejalno ci wybranych
gatunków drewna egzotycznego przy u yciu klejów PVAC i PUR. Materiaáy II.
MiĊdzynarodowego Seminarium nt. NowoĞci w dziedzinie klejów stosowanych do stolarki
budowlanej 05.11.1997, Pozna ; 99104.
3. Proszyk S., Przybylak A. 1986: Wp yw ubocznych sk adników drewna na utwardzanie
rodków wi cych i uszlachetniaj cych. Skrypty AR w Poznaniu.;
4. Sudo E., 2007: Research on strength and resistance of glue line from PVAC adhesive and
selected exotic wood species. Ann. WULS SGGW, For. and Wood Technol. 62;
265y270;
296
5. GS III.11/2003 dotycz ce wymaganych w a ciwo ci pó fabrykatów z drewna iglastego
klejonego warstwowo, stosowanych do produkcji stolarki budowlanej zewn trznej,
opracowanie wewn trzne Instytutu Techniki Budowlanej w Warszawie.
Streszczenie: WytrzymaáoĞü na Ğcinanie poáączeĔ klejowych z klejów PVAC i wybranych
gatunków drewna egzotycznego. W pracy zaprezentowano wyniki bada nad wytrzyma o ci
i odporno ci po cze klejowych z 2K klejów PVAC z utwardzaczem izocyjanianowym i
utwardzaczem na bazie Al(NO3)3 – i wybranych gatunków drewna egzotycznego: sapeli, sipo,
eukaliptus i white meranti. Okre lono wytrzyma o po cze klejowych na cinanie po
oddzia ywaniach charakterystycznych dla elementów przeznaczonych do produkcji okien.
Ewa Sudo
Pawe Sulik
Building Research Institute
Department of Structures and Building Elements
02656 Warszawa, ul. Ksawerów 21
[email protected]
Forecast of the trend of Slovak Republic economic performance - the basis
of opportunities for future development of enterprises
ANDREA SUJOVÁ; MARIANA SEDLIA IKOVÁ
Abstract: Forecast of the trend of Slovak Republic economic performance - the basis of opportunities for future
development of enterprises. The Macroeconomic performance of the economics is one of the main factors of
macro background of enterprises. It mentions the efficiency level of enterprises in different sectors and branches
of economics. It is possible to estimate the expected trends in the efficiency of enterprises on the base of
forecasts of future economic development. The article deals with forecasting of the economic performance of
Slovakia for period 2010 – 2015 with suggesting the opportunities for the future economic development and
development of enterprises in SR.
Keywords: performance of the economic, GDP, forecasts of the economics development, unemployment
INTRODUCTION
The standard of living, prosperity and development in each country depends mainly on the
adjustment of economic and political system of the country. Phenomena that have significant
impact on the economic of each state are defined as unemployment, inflation, changes in
interest or tax rates, and many other economic occurrences and range of activities that need to
be constantly reviewed and properly coordinated (Biernacka, 2009). Successful economic
development of the country impacts largely investment development projects that are closely
linked to the state's ability to repay successfully their debt. Investing has always been, and
will be in the future, the right driver for each economy. The aim of this paper is to present
forecasting of the economic performance of Slovakia for period 2010 – 2015 with
suggesting the opportunities for the future economic development and development of
enterprises in SR.
The trend of the economic performance depends mainly on the success of the state
economic politics. Economic policy creates and defines key and legal conditions of
environment for the increase of the economics performance. Integrated conditions for
functioning of the market are created this way. Economic phenomena and forms of market
system are extremely important for building of economic policy and its economic and
political system, which is aimed specifically at achievement of higher performance of the
economy. We must not forget the legal form of a market system, which together form the
economic mechanism. The economic policy itself can not be realized without the policy.
Political parties are carriers of political opinion. The individual parties are different in their
economic and political programs and stated goals that they want to achieve during the
election period (Vincúr, 2002).
Forecast of the future trend of economic performance of Slovak republic is based on the
development of macroeconomic indicators in the previous period since 1993. It was possible
to use a statistical method of estimation of the future development of the temporal series and,
at once, factors affecting the economic development of SR in the future period were
298
accounted. Forecasting of the future economic development of SR for period 2009 - 2015 is
significantly affected by the current global economic crisis, which has sharply slowed
divergent economic performance of SR. However, the forecasts themselves are not as
negative as it was initially expected, but of course a significant drop of economic performance
took place from year 2008 to years 2009 and 2010. The growth of economic was expected
according the estimates of 5 % in October 2008 but due to the economic crises it was only 0,8
% in March 2009.
Significant factors that will affect the performance of the Slovak economy in the following
period:
- External factors which will not be possible to be effected directly by domestic economic
policy; mainly solving of the global economic crisis what will significantly affect the
external demand.
- Internal factors that will affect the performance of Slovakia's economy are primarily:
the tax systems, condition of the banking sector, direct instruments of government for the
fight against the crisis impacts, and of course the new right-wing government in the
period of years from 2010 to 2014.
Slovak economy got into recession in 2009. It is expected the increase of the economic
performance about 0.4% in the second half of the year 2010 and the revival of the global
world economics from recession in the same time. Trend of the Gross Domestic Product
(GDP) and the parts of it used after the year 2010 is questionable. From the presented reason,
the forecast is cautious for this period, in view of GDP growth in the range of 3-6% per year.
It is only the forecast of course, so the forecast period may not be in that range. The growth of
domestic demand will contribute especially to the growth of GDP.
80
70
60
50
40
30
20
10
2017
2016
2015
2014
2013
2012
2011
2010
2009
2008
2007
2006
2005
2004
2003
2002
2001
2000
1999
1998
1997
1996
1995
1994
-10
1993
0
K oneē ná s potreba verejnej s právy
K oneē ná s potreba domác nos tí
T vorba hrubého kapitálu
is tý export
Fig. 1 Gross Domestic Product and parts of its using
(Source: Bureau of Statistics and model enumerations of authors)
Additional text:
Kone ná spotreba verejnej správy = Final consumption by public administration, Kone ná spotreba domácností
=Final consumption by households, Tvorba hrubého kapitálu = Generation of gross capital, istý export = Net
export
299
20%
15%
10%
5%
2017
2016
2015
2014
2013
2012
2011
2010
2009
2008
2007
2006
2005
2004
2003
2002
2001
2000
1999
1998
1997
1996
1995
-5%
1994
0%
-10%
-15%
Zahraniē ný dopyt
D omác i dopyt
R as t HD P
Fig. 2 The growth of Gross Domestic Product and contributions of domestic and foreign
demand to its growth
Additional text: Zahrani ný dopyt = Foreign demand, Domáci dopyt = Domestic demand, Rast HDP = Growth
of GDP
Trend on the labour market is clearly marked by the simultaneous decreasing of demand,
especially regarding industrially produced products; that will result in reduction of output,
services, and further declines of employment. The average employment would have fallen by
almost 25,000 employees in 2010. It means decrease of more than 2%. This prognosis was
made on the base of selected finding of labour power. The unemployment rate should
increase to nearly 11-13% by the assumptions about stable rate of growth of the economically
active population as well as by the assumption that occupants of SR working abroad will
come back (Figure 3). In the next period, the growth of demand for labour should have
copied the trend of GDP, what means only a smooth growth.
25%
2600
20%
2500
15%
2400
10%
2300
5%
2017
2016
2015
2014
2013
2012
2011
2010
2009
2008
2007
2006
2005
2004
2003
2002
2001
2000
1999
1998
1997
1996
1995
-5%
2200
1994
0%
-10%
2100
2000
Zamestnaní, VZPS
Rast reálnej mzdy
Miera nezamestnanosti, VZPS
Fig. 3 Trend of basic indicators of the labour market
Additional text:
Zamestnaní = Employed, Rast reálnej mzdy = Real wage, Miera nezamestnanosti = Rate of unemployment
The development of Slovakia's economic performance is strongly linked with the
activity of a new government. If the government of Robert Fico had again succeeded, which
was socially oriented, so the development of the economy would have progressed in a
positive direction; but the positive effects would not be as significant as they are by the
300
current right-wing government of the SDKÚ- DS party with SAS party, which has, in its
ranks, many experts in the individual branches. The government of the SDKÚ-DS managed to
restore the balance and to boost its economic growth in the past, in years 1999 - 2006. In the
following four-year period, the improving of economic performance and living standard will
be therefore promoted through investment development programs, which contribute more
effectively to the growth of the economy performance than government social programs of
Robert Fico.
In consideration of suggestions for future opportunities for the successful development
of economic performance, it is expressly necessary to promote development programs
focused on small and medium-sized enterprises, which represent approximately 96% of all
enterprises in Slovakia. The particular support of small and medium-sized enterprises should
come in the form of minimizing of tax barriers for these companies.
The proposed solutions are:
- opportunity don’t tax 40% profit before tax and the opportunity to apply for the so-called
return of investment capital for these small and medium-sized enterprises,
- to invest to the better orientation of the educational system for training of future
entrepreneurs, it means device economic and investment subjects to the education content
of secondary grammar schools, high schools and vocational schools,
- to improve the infrastructure of highways, to improve the quality of health services, and
to support an entry of investors to the eastern Slovakia, and to reduce gaping regional
disparities to a minimum this way.
CONCLUSION
The performance of the Slovak economy has got the potential to move forward. The
question is what kind of conditions will be created to its support. And therefore the economic
actions of the new government, as well as the ability of the individual coalition parties to
create a strong, stable, and particularly useful government coalition, will have the great
importance for Slovakia in the future. This coalition have to use the existing potential hidden
in the Slovak economy and have to really try to care about the maximization of improvements
in macroeconomic indicators and about the maximization of environmental well-being of all
occupants of Slovakia.
Acknowledgement
This paper was processed in the frame of the project No. 1/0151/10 as the result of author’s
research at significant help of VEGA agency, Slovakia.
REFERENCES
1. Biernacka J.: Economic crisis and its influence on condition of Forte SA and Paged
SA – polish wood sector companies listed on Warsaw Stock Exchange, Annals of
Warsaw University of Life Sciences – SGGW, 2009, ISSN 1898-5912.
2. Klein, T., Bahýl, V., Vacek, V.: Základy pravdepodobnosti a matematickej štatistiky.
Zvolen: Vydavate stvo TU Zvolen, 1997. 236 s.
3. Kostiviarová, S., Sopková, E.: The importance of business incubators in the world and
in Slovakia. In: Studia Universitatis „Vasile Goldis“ Arad – Economic Sciences, issue
1-3/2009, on www.ceeol.com. p. 1-12. ISSN 1584-2339.
4. Vincúr, P a kolektív. Hospodárska politika. Vysokoškolská uþebnica. Bratislava:
SPRINT, 2002, s. 43- 44. ISBN 80-88848-99-7
5. http://portal.statistics.sk
301
Streszczenie: Prognoza trendów ekonomicznych Republiki Sáowacji – podstawa przyszáego
rozwoju przedsiĊbiorstw. Makroekonomiczna ocena ekonomii jest jedn z g ównych podstaw
makroekonomii przedsi biorstw. Istnieje mo liwo
przewidywania bie cych trendów
ekonomiki przedsi biorstw na bazie prognoz rozwoju ekonomicznego. Artyku dotyczy
prognoz dla S owacji w latach 2010-2015 wraz z sugestiami rozwoju ekonomicznego
przedsi biorstw.
Ing. Andrea Sujová, PhD.
T. G. Masaryka 24
960 53 Zvolen
Slovakia
phone: 00421-045-5206438
Ing. Mariana Sedlia iková, PhD.
T. G. Masaryka 24
960 53 Zvolen
Slovakia
phone: 00421-045-5206420
Designs of wooden floorings in historical buildings in the Kolbuszowa
County
IRENA SWACZYNA, ANDRZEJ K DZIERSKI, ANNA RÓ A SKA, AGNIESZKA
SZYMCZYK, ANDRZEJ TOMUSIAK, ZOFIA R EWSKA
Abstract: The study presents the design of historical decorative wooden floorings in four buildings in the
Kolbuszowa County. Design characteristics consist of showing the floorings aspect, direction of fibres, kinds of
wood as well as the kind of sections of the components forming the panel design. Additionally, original interiors
were measured, and the arrangement and design of the panels was marked. Apart from the design, the structure
and dimensions of the panels were specified.
Keywords: flooring, panel, structure, design, manor house
INTRODUCTION
In Kolbuszowa County in Podkarpackie District, there are several historical manor
houses with adjacent buildings, where original decorative wooden panel floorings have been
preserved. A manor house is a residential building serving for wide variety of dwellers. It may
resemble a peasant cottage or take the form of a small palace. The architectonic model of the
manor was often copied in annexes, vicarages and inns. Its layout is usually practical – manor
house is a one-storey building, often on a rectangular plan, its construction is not a
complicated enterprise and its design and dimensions may be easily altered afterwards. Manor
houses were usually made of wood, a resource easily accessible on the grounds of
Sandomierz Forest, and had shingled roofs. Preceded by a porch, there was a middle entrance
hall having mostly brick floor as well as whitewashed walls with ceiling made of sawn timber
or canvas. On the sides of the entrance hall, there were guest rooms, bedrooms, studies,
dressing rooms, chambers and corner annexes. Their floorings were made of wood. It could
be simple floors made of boards or sometimes the boards were decoratively arranged into
squares between the front slats. Sometimes, such blind floors were covered with decorative
panels with geometric patterns or even elaborate rosettes. For this reason, the design of manor
house floorings depends significantly on their representative character and expresses the
ambitions or social status of the owners.
SELECTION AND CHARACTERISTICS OF THE BUILDINGS
The main criterion while selecting the objects of the study was the originality of their
decorative wooden floorings. Although Kolbuszowa County boasts numerous manor houses,
only four buildings were fit to study the flooring design. As a result of the change of their
purpose, the interiors of manor houses and palaces (e.g. Tyszkiewicz Palace in Werynia and
Manor House in Dzikowiec) were laid out in a new way. Due to improper use they gradually
became dilapidated, and the new owners, while bringing back their former magnificence,
usually completely replaced their floors or even the entire joinery. During the refurbishment
works, historic floorings were of the least concern and were, even without recording the
original state, replaced with the modern floor panels (as it happened in the manor house in
Niwiskie).
303
Adopting the said principle, i.e. the originality of the floorings, resulted in selecting four
objects of study in Kolbuszowa County: manor house in Witkowice and Niwiskie, manor
house outbuilding in Kolbuszowa and vicarage in Ostrowy Tuszowskie. The project is a part
of the research grant No. 1374/B/P01/2008/35 focusing on the analysis of design, structure
and workmanship of decorative wooden floorings in manor houses and palaces in Southeast
Poland.
The manor house in Witkowice ( nie y ska-Stolotowa, Stolot 1991, Swaczyna,
Ró a ska 2010), was constructed between 1797-1806 for the Lubienieccy family and
designed most probably by Jakub Kubicki, the eminent royal architect of the Stanis aw
Poniatowski era. It has distinct features of a small classical palace. Kubicki is credited also
with two outbuildings. The whole complex has been thoroughly renovated and is in the hands
of private owners. The manor house itself is a masonry, one-storey building (two-storey on
the extreme axes) with a cellar and hipped roof, presently covered with metal sheets. The
palace has a rectangular plan with central and lateral risalits where the elevation is longer, a
risalit, as well as a one-storey extension from the West and a portico from the East. There are
five-axis, two-bay interiors in the central part and three-bay interiors on the extreme axes. The
rooms were designed as an enfilade. Along the central axis, there is a Hall and behind it, in
the garden section, a living room called the Banquet Room. It has a circular plan, the circle
being demarcated from a square by Ionic columns, with alcoves in the corners, covered with
semi-domes. It is crowned with a flattened dome with a central plafond. The central plan of
the Banquet Room interior is marked by a decorative floor rosette made of several kinds of
wood, although only its central part is genuine. The remaining part of the Banquet Room
flooring, as well as the geometric wooden panel floorings in the side rooms, are a
reconstruction. The reconstruction of panel floorings was possible on the basis of the
preserved basic panels, kept in the Castle Museum in a cut (Muzeum Zamek w a cucie).
The manor house in Niwiskie (Malczewski 1978) has been gradually converted from
wooden into masonry mansion since 1850. The sources did not record the subsequent phases
of the conversion. The building plan comprises two rectangles positioned as to form the right
angle. The main entrance is located on the West side of the elevation. The part of the building
located on the North-South axis is a one-storey construction with three-hipped mansard roof.
The other part, located on the East-West axis, is a two-storey construction, topped with
saddleback roof and triangle gables. The roof from the East side is extended and its eaves
forms an arcade supported by pillars. In the section where Eastern and Southern parts join, the
eaves becomes more distinct and is supported by four pillars jutting out from the porch line.
The Western elevation has two significant risalits, southern being the dominant height of the
building. The central part of the elevation is a one-storey construction, covered with mansard
roof. The last owner of the manor house, doctor Jan Antoni Ernest Hubka, added the porch
and the terrace on the Southern elevation as well as the railing with turned balusters to the
collonade in the garden elevation from the East. Towards the end of the XIX century, Jan
Hubka asked his friend from the cabaret named „Zielony Balonik”, well-known painter and
designer Karol Józef Frycz, to design the interiors. As a result, Frycz completed polychromies
in three rooms on the base floor and in two rooms upstairs. After the war was over, the manor
house was taken over by the state and was subsequently devastated. Many paintings were
destroyed, among others, the wall dividing the Baboon Room (Dining Room) and the Office
was brought down, and the enlarged room was turned into a local cinema. Precisely in this
room a panel geometric pattern of the decorative wooden flooring was preserved. Similar
flooring with different pattern was preserved in the room upstairs until 2009. It was replaced
with modern panels, and the fate of the original panels is unknown.
The manor house outbuilding in Kolbuszowa (Skowro ski 2000, nie y ska-Stolotowa,
Stolot 1991), built in the second part of the XVII century, located by the two-storey
304
Lubomirski palace, is a one-storey (although with a cellar) plastered log construction made of
larch. Erected on a rectangular plan, with two-bay interiors and hipped roof, currently covered
with metal sheets. Toward the end of the XVIII century it was adopted as the residence of the
new owners of the town – the Tyszkiewicz family. In the middle of the XIX century, as the
Tyszkiewicz family moved to Werynia, it was inhabited by numerous subsequent owners who
also introduced certain changes to its layout. It presently hosts the offices of the Muzeum
Kultury Ludowej (Folk Culture Museum) in Kolbuszowa. The outbuilding was fitted with oak
panel floorings with geometric pattern, disassembled during the general refurbishment
between 1984-89, several of these panels were preserved.
The vicarage building in Ostrowy Tuszowskie (Skowro ski 2000, nie y skaStolotowa, Stolot 1991) was erected nearby the parish church founded in 1901-1902. The
present wooden vicarage building, which replaced the former ones, is made of larch acquired
during the demolition of the church founded in 1593. It is a one-storey construction on the
plan of elongated rectangle, with a porch, topped with a saddleback roof and gables boarded
with planks. Interiors follow the common manor house enfilade design, with entrance hall and
a large room on the axis as well as two-bay residential rooms on the sides. Each room had a
wooden flooring. The representative rooms had panel floorings with geometric pattern, while
the less official once had floor boards with decorative square pattern divided by front boards.
In the end of 2009, the administration of the vicarage was taken over by the Muzeum Kultury
Ludowej (Folk Culture Museum) in Kolbuszowa. As a result, it was disassembled with the
purpose of reconstructing it in the ethnographic park, as a part of the planned church and
vicarage complex. Prior to disassembly of the floorings, a detailed conservator record had
been prepared; and the original panels are stored in the Museum.
DESIGN AND STRUCTURE CHARACTERISTICS OF THE FLOORINGS
While characterising the design of the floorings, the following works has been carried
out: general or detailed photographs of the interior floorings, drawings of the basic panels
with indication of the species of wood used as well as the fibre direction of the components of
the panels along with the section type. Additionally, original interiors were measured and
layout plans of the panels in the rooms were prepared, which allows for precise determination
of the panels quantity and constitutes a detailed documentation of the floorings.
The most decorative floorings are to be found in the manor house in Witkowice. In this
case, floorings design is determined by the formal character of the interiors. The rosette in the
Banquet Room corresponds with the lavish piano nobile floorings in the Castle in a cut. The
floorings preserved in two other rooms of Witkowice mansion – Billiard Room and Dressing
Room – also modeled after a cut, are more practical, although not without aesthetic value.
The pattern and layout of the rosette panels and the floorings of the mentioned rooms is
presented on the drawings 1a, 1b and 1c.
The flooring design in the Niniwskie manor house is shown on the drawings 2a, b, c and
d. The flooring shown on the drawing 2d has been replaced, as mentioned, with panels.
The flooring design in the outbuilding in Kolbuszowa is presented on the drawing 3, and
of the vicarage in Ostrowy Tuszowskie, on the drawings 4a and 4b.
The components of the panels are connected in a tongue and groove technique. Take
note that the justification for the selection of specific kinds of wood, particularly abundant in
the rosette, was not only the colouristic values of the various kinds of wood, but also their
similar functional features, such as density, wear resistance and hardness (Swaczyna,
Tomusiak, K dzierski, Koryci ski, Polici ska-Serwa 2009).
The panels are nailed to the blind floor which is itself nailed to the ground beams
(drawings 5a,b,c). Between the blind floor boards and the panels, there is a layer of sand for
levelling and smoothing the face side of the panel (drawing 5b).
305
SUMMARY
The flooring design in the historical buildings of the Kolbuszowa County is diverse,
always geometric, with the correct selection of wood types. The panels are of single layer
structure. The bottom surface is uneven, hence the need to use sand as a subfloor on the blind
floor.
a
b
c
Drawing.1. Witkowice: a- pattern and wood species (taxus, oak, dark oak, beech) of the rosette in the Banquet
Room (R.1090mm), b- pattern and wood species (oak, beech) of the Library panels (625x625mm), c- pattern and
wood species (oak, pine) of the Dressing Room panels (625x625mm)
a
b
c
d
Drawing 2. Niwiska: a- pattern and fibres direction of the Baboon Room oak panels (505x505mm), b- pattern
and wood species (oak, birch) of the Crow Room (Pokój pod Wronami) (505x505), c- pattern and wood species
(oak, ash) of the panels from the first floor Corridor (620x620mm), d- pattern and fibres direction of the oak
panels from a first floor room (620x620mm)
Drawing 3. Panel from
Kolbuszowa (oak), pattern and
fibres direction
a
b
Drawing 4. Ostrowy Tuszowskie: a- pattern and wood species (oak,
pine) of the panel (900x900mm), b- scheme of the panel layout in
the room
a
b
c
Drowing.5. Floorings’ layout: a,b- flooring from Ostrowy Tuszowskie with the sand layer visible, c- forged nail
that joined Kolbuszowa panel with the blind floor
306
REFERENCES
1. MALCZEWSKI J., 1978: Niwiska Dwór. Dokumentacja naukowo-historyczna
opracowana na zlecenie Urz du Gminy w Niwiskich k. Kolbuszowej, Pracownie
Konserwacji Zabytków Oddzia w Rzeszowie. Pracownia Dokumentacji NaukowoHistorycznej, Rzeszów.
2. SKOWRO SKIi M., 2000: Powiat Kolbuszowski, Kolbuszowa
3. SWACZYNA I., TOMUSIAK A., K DZIERSKI A., KORYCI SKI W.,
POLICI SKA-SERWA A., 2009: Indentation and abrasian resistance of decorative
wood floorin of the Castle in a cut [w:] Ann.WULS-SGGW, For. And Wood
Technol., nr 69.
4. SWACZYNA I., RÓ A SKA A., 2010: Preliminary Guidelines Concerning the
Design of the Decorative Wooden Flooring in a 19th-Century Manor House under
Reconstruction [in:] NABYTOK 2010. 8th Symposium FURNITURE 2010, Technical
University in Zvolen, Faculty of Woodscience Technology, Department of Design
furniture and wood products.
5. NIERZY SKA-STOLOTOWA E., STOLOT F., 1991: Katalog Zabytków Sztuki w
Polsce, T.3, z.3, Kolbuszowa, Mielec i okolice, Warszawa.
Streszczenie: W pracy przedstawiono wzornictwo zabytkowych ozdobnych posadzek
drewnianych znajduj cych si
w czterech obiektach powiatu kolbuszowskiego.
Charakterystyka wzornictwa polega na przedstawieniu widoku, kierunku przebiegu w ókien,
gatunków drewna oraz rodzaju przekroju elementów tworz cych wzornictwo tafli. Ponadto
mierzono wymiary oryginalnych wn trz i nanoszono uk ad i liczb tafli. Oprócz wzornictwa
okre lono konstrukcj i wymiary tafli.
Irena Swaczyna
Andrzej K dzierski
Anna Ró a ska
Andrzej Tomusiak
Zofia R ewska
02-787 Warsaw,
Poland
e-mail: zofia_r [email protected]
Usability of wood-based materials as a supporting layer of PCB
M. SYDOR1, M. SZULC2, B. PA UBICKI1
1
2
University of Life Sciences, Faculty of Wood Technology, Pozna , Poland
Poznan University of Technology, Faculty of Computer Science and Management, Pozna , Poland
Abstract: Usability of wood-based materials as a supporting layer of PCB. The paper describes materials used
for printed circuit boards (PCB). Major problems faced during the process of recycling of wastes from electronic
equipment containing PCBs are discussed. At the present time, more than 70% of the total bulk of recovered
wastes undergoes utilisation and only 30% is recycled. Therefore, it has been proposed to replace laminates
widely used as carrier materials in PCBs by biodegradable wood-derived materials. Significant wood structural
properties were compared with those of the currently applied materials. In conclusions, advantages and
disadvantages of wood-derived materials used in electronic equipment were collated.
Keywords: PCB, recycling technology, wood based PCB
INTRODUCTION
A printed circuit board (PCB), is widely used to mechanically support and electrically
connect electronic and electromechanical components. Basic structural elements of PCBs are:
conductive pathways, tracks or signal traces etched from metal sheets laminated onto a nonconductive substrate. The circuits in PCB are formed by a thin layer of conducting material
deposited, or "printed", on the surface of an insulating board known as the substrate.
Electronic components are soldered to the interconnecting circuits (two technologies are used:
traditional THT - Through-Hole Technology and more modern SMD - Surface Mount
Device) [6].
Printed circuit boards were invented in the 1940s, modern PCBs were introduced in the
1970s, and till now are commonly used. In contemporary PCBs conducting layers are
typically made of thin copper foil. Insulating layers dielectric are typically laminated together
with a glass fiber reinforced (fiberglass) epoxy resin. The board is usually coated with a green
solder mask (blue and red colors of solder mask are available too).
Large quantities of nonmetals in PCBs (up to 70%) are a major challenge for recycling
[1]. Nonmetals of PCBs generally consist of thermoset resins and reinforcing materials which
are incompatible in the recycling processes. Thermoset resins cannot be remelted or reformed
due to their network structure. Incineration is not the best method for treating nonmetals
because of inorganic fillers such as glass fiber, which significantly decrease the fuel
efficiency. In addition, the combustion of electronic waste in the presence of copper from
PCBs may lead to higher emissions of polychlorinated dibenzo-para-dioxins (PCDDs) and
dibenzofurans (PCDFs) into the environment, causing even worse environmental pollution
[3].
PCBs AND THE ENVIRONMENT
Each product, to a smaller or greater extent, exerts a negative impact on the environment.
Life-cycle of the majority of contemporary products is long and complex and this also refers
to PCBs. This period includes, among others, phases of product design, technology
elaboration, raw material preparation, manufacturing, distribution, and utilisation, repair,
recycling and rendering the products harmless. The designing phase of each product appears
to exert a key role with regard to its future onerousness for the environment as it is the
designer who decides, among others, about the energy consumption of the product as well as
its future recyclability.
308
Design for environment (DfE) is a designing philosophy in which special emphasis is
placed on the reduction of noxious effects on the environment exerted by industrial products
in the course of all stages of the product life-cycle. Forward planning of recycling possibilities
in the early stage of product design increases considerably the percentage proportion of
materials recoverable as a result of waste recycling.
According to DfE principles, products must be designed in such a way as to increase in
them quantities of materials suitable for recycling and to expand the use of raw materials
derived from recycling (the so called ‘recyclates’). When ‘designing for recycling’, it is
essential to constantly bear in mind the principle of the reduction of diversity of material used
in the product. In particular, it is not advisable to employ materials incompatible in recycling
where one of the constituent contaminates recyclates.
PCBs production and utilisation are quite onerous for the environment [1]. Wet chemical
processes widely employed in these processes devour considerable quantities of water and
energy and require application of chemical compounds which constitute potential hazards for
human health and environment.
Contemporary technologies employed in the recycling and utilisation of PCBs can be
divided into two groups: thermal technologies of the type of pyrolysis, hydro-metallurgy and
metallurgy as well as non-thermal technologies such as: disassemble, disintegration,
separation and chemical treatment mentioned earlier [2]. Application of wooden PCBs allows
employment of a completely new method – low energy-consuming and safe biological
method, in other words, it allows application of fungi or microorganisms to degrade electronic
wastes. Cheap biological utilisation of the wood carrier layer facilitates subsequent separation
of the remaining substances (metals, small quantities of ceramics and plastics).
PCBS MADE FROM WOOD
Electrical properties of wood-derived materials do not differ significantly from the
identical properties of typical laminates manufactured from epoxy or phenolic resins
traditionally applied in electronics (Tab. 1).
Table 1. Chosen properties of boards materials (based on [4], [5], [6])
Material
Reinforcement
Matrix
FR1/ FR2
Paper
Phenolic resin
FR3
Paper
Epoxy resin
CEM1
Paper
Epoxy resin
CEM3
fibreglass
Epoxy resin
Plywood Cellulose fibbers
lignin
HDF
Cellulose fibbers
lignin
Di / TetraFR4
fibreglass
epoxy resin
Tetra / MultiFR5
fibreglass
epoxy resin
BT- epoxy
FR5 BT
fibreglass
resin
Poliimide
fibreglass
Polyimide
Approximate
Max. long-term
prices (in
Loss
operating
Permittivity
comparison
tangent
temperature
to FR4)
0,2-0,3
70° C
4,25
0,05
0,5-0,6
90° C
no data
0,041
0,7-0,8
no data
no data
0.031
0,80-0,85
no data
no data
no data
0,15-0,20
120° C
2,0-8,0
0,054
0,04-0,05
130° C
3,0-6,0
0,04
1
115-180° C
3.8-4.5
0,019
1,4-1,6
140-175° C
no data
0,016
3
no data
no data
0,015
3,0-4,4
230-260 ° C
no data
no data
309
Careful analysis of Table 1 shows that specificity of wood-derived boards cause that their
individual electrical properties are contained within wide boundaries. Plywood and HDF are
characterised by layered structure. Similarly to other materials containing fibrous fillers,
especially those of layered structure, they are characterised by anisotropy of relative electric
permittivity and of loss tangent coefficient. The scatter of the above properties can be
attributed to two causes. Different layers of plywood or HDF board can have different
material parameter values. Individual layers in board wood-derived materials, due to poor
homogeneity, are characterised by heterogenous volume structure.
Moreover, electric permittivity and loss tangent coefficient of dielectric materials also
depend on temperature, intensity of electric field and moisture content as well as on the
frequency of the electromagnetic field. The above properties change together with aging of
the material [5].
SUMMARY
Advantages of the application of wood derived materials for PCBs include:
• Nontoxicity,
• Recyclability, especially to biological degradability,
• Lower energy consumption during machining, e.g. lower ducking of drills,
• Good electrical parameters,
• Smaller specific gravity.
Potential disadvantages include:
• Poorer heat removal from mounted elements,
• Hygroscopicity and dimensional changeability connected with it,
• Changeability of construction properties in time.
Nevertheless, despite these shortcomings, wood-derived materials constitute a promising
material for PCBs.
REFERENCES
1. DESIGN FOR THE ENVIRONMENT PRINTED WIRING BOARD PROJECT
FACT SHEET (EPA/744-F-99-006). U.S. Environmental Protection Agency, 2000
2. W. KORNACKI, Recycling p ytek drukowanych, Recykling 2 (2004) p. 24
3. J. GUO, J.GUO, S. WANG, Z. XU, asphalt modified with nonmetals separated from
pulverized waste printed circuit boards, Environ. Sci. Technol., 2009, 43 (2), pp 503–
508
4. CHEN WANG, DETERMINING DIELECTRIC CONSTANT AND LOSS
TANGENT IN FR-4. UMR EMC Laboratory Technical Report: TR00-1-041, 2000
5. MICHA LISOWSKI. Pomiary rezystywno ci i przenikalno ci elektrycznej
dielektryków sta ych. Oficyna Wydawnicza Polit. Wroc., Wroc aw 2004
6. C.F. COOMBS, PRINTED CIRCUITS HANDBOOK, McGraw-Hill, 2007
310
Streszczenie: PrzydatnoĞü tworzyw drzewnych jako warstwy noĞnej páytek PCB. W artykule
opisano materia y stosowane na elektroniczne p ytki drukowane (PCB). Wskazano
podstawowe problemy w trakcie recylingu odpadów z urz dze elektronicznych
zawieraj cych PCB. Obecnie ponad 70% masy pozyskiwanych odpadów podlega utylizacji, a
jedynie 30% ponownemu przetworzeniu. W zwi zku z powy szym zamiast powszechnie
stosowanych laminatów zaproponowano biodegradowalne tworzywa drzewne jako materia
no ny p ytek PCB. Porównano istotne w a ciwo ci konstrukcyjne drewna z analogicznymi
w a ciwo ciami dotychczas stosowanych tworzyw. W podsumowaniu zestawiono wady i
zalety tworzyw drzewnych w zastosowaniach elektronicznych.
Maciej Sydor, University of Life Sciences, ul. Wojska Polskiego 28, 60-637 Pozna , Poland
(Ann. WULS – SGGW, For and Wood Technol. 72, 2010)
Value assessment for deciduous timber (birch, alder) logs for plywood
manufacture
MIECZYS AW SZCZAWI SKI, HANNA PACHELSKA
Department of Technology, Organization and Management in Wood Industry, Warsaw University of Life
Sciences – SGGW
Abstract: Value assessment for deciduous timber (birch, alder) logs for plywood manufacture. This paper is the
next outcome of the Zespó Organizacji, Ekonomiki i Projektowania Zak adów Przemys u Drzewnego team
work on the basic subject of „Metody wyceny warto ci surowca drzewnego w przerobie przemys owym” (Value
assessment methods for raw materials in industrial processing). A simplified calculation formula is applied
because the influence of some factors on the results is insignificant (Szczawi ski M., Jenczyk-To oczko 2010).
The results of raw material value assessment in the plywood manufacture proved usability of the proposed
method, as well as showed that the traditional plywood structure (with cheaper and lower quality timber used for
internal plies) is profitable. The calculation value of timber is significantly higher than the market value thereof.
Keywords: plywood, raw material value, production profitability.
INTRODUCTION
This article is the next outcome in the sequence of the Zak ad Organizacji, Ekonomiki
i Projektowania Zak adów Przemys u Drzewnego work on the basic subject.
The practical application of the previously-proposed calculation formula induced the
research team to simplify the formula for practical application in the wood sector. The earlier
formula versions included consideration for interest rates on the capital engaged in the
manufacturing process. Still, calculation results showed an insignificant influence thereof on
the raw material value assessment (Szczawi ski, Jenczyk-To oczko 2010). Therefore, the
new methodology makes consideration for financial effects of delayed payments from
customers (‘delay’ should be understood as the time from product shipment till payment).
This document includes calculations for plywood, both for dry applications and
waterproof, 6 mm thickness, different quality grades.
METHODOLOGY
The value assessment of round timber processed into plywood was made with
application of a simplified formula containing three components:
Wdi = A – B + C,
where:
A – discounted (discounted = with consideration for interest on delayed payments from
customers) receipts from sales of 1 cu.m. of processed raw materials, for the gross
operating margin applied (= before tax), in PLN/cu.m. for raw material,
B – purchase, transport and processing costs per 1 cu.m. of raw material, in PLN/cu.m. for
raw material),
C – receipts from sales of post-processing waste, after tax, in PLN/cu.m. for raw material).
Wdi
ai ( Pi r 'z )
(1 r ) p (1 m)
kt k p f (1 vi )(co ko )
312
where:
Wdi – value of raw material being processed into ‘i’ plywood type (PLN/cu.m.),
ai – raw material processing efficiency for ‘i’ plywood type (cu.m./cu.m.),
(The involved production plant provided with the value of 0.38, which seems too low.
Nevertheless, this value was used for further calculations. In Ratajczak [1998], this
value is much higher: as high as 0.48 (attachment 3, page 205). Having adopted the
value of 0.38 (presumably, the value provided by the manufacturer was lower than the
actual value), calculations proved that the timber-into-plywood processing is highly
profitable.)
Pi – average weighted unit sales price for ‘i’ plywood type for different quality grades
(PLN/cu.m., plywood),
z – inventory difference for finished product stock (in this example: z = 0),
r – discount rate meaning the interest on capital per one day of payment delay from the
customer, adopted acc. to the interest on two-year State Treasury obligations (approx.
5% annually),
p – number of days waiting for receivables from customers (number adopted for calculations:
30 days - because after exceeding that time length, the supplier is entitled to claim
statutory interest on delay (approx. 10% annually),
f – company share in the gross profit (f2008 = 0,81), m - assumed gross profitability (before
tax) for plywood manufacture and sales,
kt – unit cost for raw material purchase + delivery to the manufacturing plant (PLN/cu.m. for
raw material),
kp – raw material-to-plywood processing cost (PLN/cu.m. for raw material),
Co – gross receipts (before tax) from post-production waste sales (PLN/cu.m., for raw
material):
Co = Cw x Uw + Cz x Uz + Czr x Uzr, where:
Cw – average sales price for post-veneering shafts (PLN/cu.m.),
Uw – shaft share
Cz – average sales pricer for edgings (PLN/cu.m.),
Uz – edgings share,
Czr – average sales price for chips (PLN/cu.m.),
Uzr – chips share.
The financial data for the year 2008 are courtesy of a significant plywood
manufacturing plant located in Poland. No further detailed data may be disclosed due to the
business secret.
VALUE ASSESSMENT FOR ROUND TIMBER PROCESSED INTO PLYWOOD
The round timber value assessment makes consideration for different 1.5 veneer
batches: two internal layers, and three external layers.
The structure of raw material consumption for plywood manufacture is a result of ply
layout within the board, and of various demands for different raw material grades. In practice,
better raw materials are used for the external layers, worse (cheaper) raw materials for
internal layers - that differentiation has been applied for many years. Additionally,
consideration should be made for more difficulties purchasing raw materials of the highest
quality in the timber market. That is the starting point for calculating the average material
purchase price, which can be the basis for comparison with the value thereof after processing.
313
The involved company uses materials for five-ply boards, with veneer thickness
of 1.5 mm:
a)
For moisture-resistant plywood:
- WAO finishing plies
0.4 x 310 = 124 PLN/cu.m.
- WCO internal plies
0.6 x 180 = 108 PLN/cu.m.
Total
232 PLN/cu.m.
b)
For water and boil-proof plywood:
- WAO finishing plies
0.4 x 310 = 124 PLN/cu.m.
- WBO internal plies
0.6 x 250 = 150 PLN/cu.m.
Total
274 PLN/cu.m.
The calculation formula makes consideration profit from waste sales. The sales value
(per 1 cu.m. of raw material) for post-production waste with the processing efficiency is
contained in Table.
Table 1. Receipts from sales of plywood production waste
Item
1
2
3
4
Waste type
Shafts
Edgings
Chips
Sawdust, dust
Average sales price
(PLN/cu.m.),; after
deduction of preparation
for sales costs
119
36
40
Total
Share (%)
30
14
51
5
100
Receipts from sales of
material waste
(PLN/cu.m.), calculated
per 1cu.m. of raw material
22.3
8.7
4.4
35,0
Source: own calculations
After deduction of 19% income tax, the net receipts will be approx. 29 PLN/cu.m. of
raw material. Receipts from sales of sawdust and dust per na 1cu.m. of raw materials were
omitted as neglectable.
The value assessment for birch and alder raw materials processed into 6 mm plywood,
three quality grades, is contained in Table 2.
Table 2. Birch and alder round timber processed into 6 mm plywood
Item
1
2
Type
Moisture
resistant
Weather
and boil
proof
2400
Discounted
receipts from
plywood sales,
per 1 cu.m. of
raw materials
(PLN/cu.m.)*
877
3000
1096
Average
weighted
sales price
(PLN/cu.
m.)
Purchase
and
delivery
Processi
ng
70
558
278
265
242
233
Average
procure
ment
price
(PLN/c
u.m.)
232
76
630
419
376
358
344
274
Costs (PLN/cu.m.
of raw materials)
Raw
materials
value
(PLN/cu.m.) fore gross profit
margin of:
0.00
0.10
0.15
0.20
* with consideration for deduction of interest on delayed payments from customers.
The calculation result analysis shows that the value of both birch of alder round timber
is significantly higher that than the average purchase price thereof resulting from the demand
structure (for 6 mm plywood). The average raw material purchase price would equal the
314
calculation value should the gross profit margin be as high as 20%. That is a confirmation that
the plywood manufacture is satisfactorily profitable.
CONCLUSIONS
A simplified timber value assessment formula can be helpful for plywood
manufacturers while negotiating with raw material suppliers. Besides, the formula
determines options for acceptance of auction prices given specific technological and
organisational conditions as well as the market situation.
With the traditional board structure, plywood manufacture is highly profitable.
REFERENCES:
1. CICHOCKA K., 2008: Dopuszczalna cena drewna okr g ego w przerobie na sklejk .
Praca magisterska, Maszynopis, Wydzia Technologii Drewna, SGGW, Warszawa;
2. RATAJCZAK E., 1998: Rynek drzewny. Analiza struktur przedmiotowych. Rozprawa
habilitacyjna, ITD, Pozna ;
3. SZCZAWI SKI M., JENCZYK – TO OCZKO I, 2009: Influence of raw material
limited availability on financial results of wood industry companies. Intercathedra nr
25, 136 – 138;
4. SZCZAWI SKI M., DOBROWOLSKA E., JENCZYK – TO OCZKO I., 2010:
Beech round wood value pricing in sawn timber processing. Annals of Warsaw
University of Life Sciences - SGGW. Forestry and Wood Technology 2010, nr 70,
279 – 284;
5. SZCZAWI SKI M., BIERNACKA J., 2010: Valuation of experimental sawing of
low-grade pine logs (WCO). Intercathedra nr 26;
6. SZCZAWI SKI M., JENCZYK – TO OCZKO I, 2010: Application of modified
method of beech round wood value pricing. Annals of Warsaw University of Life
Sciences - SGGW. Forestry and Wood Technology 2010, nr 71.
315
Streszczenie: Wycena wartoĞci liĞciastego drewna okrągáego (brzoza, olcha) w przerobie na
sklejkĊ. Publikacja stanowi kontynuacj prac zespo u Organizacji, Ekonomiki i Projektowania
Zak adów Przemys u Drzewnego nad tematem statutowym „Metody wyceny warto ci
surowca drzewnego w przerobie przemys owym”. Wykorzystana zosta a uproszczona formu a
rachunku, bowiem wp yw niektórych czynników na wyniki oblicze okaza si by
nieistotnym (Szczawi ski M., Jenczyk-To oczko I. 2010). Wyniki wyceny warto ci surowca
w przerobie na sklejk wykaza y przydatno proponowanej metody oraz fakt, i op acalne
jest stosowanie tradycyjnej konstrukcji arkusza przez wykorzystania gorszego, ta szego
drewna na warstwy wewn trzne. Warto obliczeniowa drewna jest znacz co wy sza ni jego
cena rynkowa.
Sáowa kluczowe: sklejka, cena surowca, op acalno
produkcji.
Mieczys aw Szczawi ski
Department of Technology, Organization and Management in Wood Industry,
02-776 Warsaw,
Hanna Pachelska
02-776 Warsaw,
The verification method of the production assortment structure in the
furniture factory
MIECZYS AW SZCZAWI SKI; MAGDALENA OLKOWICZ
Department of Technology, Organisation and Management in Wood Industry; Warsaw University of Life
Sciences;
Abstract: The verification method of the production assortment structure in the furniture factory The proposed
model can facilitate the verification of the production assortment structure by taking account of changes in a cost
per unit of given product, its sales volume and selling prices in the test measurement periods: the shaping a more
profitable market offer takes account of the main restrictions of the function growth by criterion ('Zn), that is
absorbency and production capacity.
Keywords: verification method, assortment structure, furniture, product,
INTRODUCTION
In business activity of industrial plants, including furniture factories, we can meet with
the problems of forming a rational production assortment structure in a given stage of the
cycle of economic situation. The offer of products should be conducive to maximize the
operational profitability of manufacture and sale. This depends mainly on the products
attractiveness in relation with proposed prices in the circumstances of increasing competition,
such as manufacturers in Asia. In the furniture industry, the main factor, which determinants
buyers’ interest in given type of furniture, is the exterior appearance corresponding with
current fashion trends. Therefore, we can have to do with various moments of coursing of the
life cycle each furniture group in the factory offer. Thus, the question of relatively close
verification of the production structure, is open. It is also heads for disclosure of products,
which profitability can decrease in the background of total production.
The verification can incline to take action in the direction of replacement the products,
that at that time of measurement period are in the decadent phase of their life cycle, with new
type of products.
MODEL OF ANALYSIS THE PRODUCTION ASSORTMENT STRUCTURE
Considering changes in net operating profit of the whole plant and its production range
of products, we analyze the impact of three major factors, i.e. changes:
- unit costs of production,
- volume of sold production,
- unit prices.
The fundamental instrument, which decides about economic prosperity of the plant, is a level
a net profit from business activities and its changes. There are especially changes in the net
operating profit from the basic activity i.e. the furniture production. Thus, the increase in net
operating profit for the adopted measurement period, i.e. month or quarter, will be:
'Z n
f 'Zb
where:
'Zn increase in net operating profit during the considered period,
'Zb increase in gross profit (before taxation during the considered period),
f
share ratio of factory in gross profit,
317
The increase in gross profit ('Zb ) will consist of:
'Zb
'K ' P 'C
where:
'K value of economic effect, i.e. profit or loss as a result of changes the unit costs of
production,
'P value of economic effect as a result of changes the volume of sold production,
'C value of economic effect as a result of changes the unit costs,
where:
'K
'P
n
¦ (ki1 ki 2 ) Pi 2
i 1
n
¦ (ci1 ki1)( Pi 2 r 'Z pi 2 Pi1 r 'Zpi1)
i 1
'C
n
¦ (Ci 2 Ci1) P i 2
i 1
where:
ki1, ki 2
ci1, ci 2
Pi1, P i 2
unit cost of production i product, after start and after finish the measurement
period,
unit price of i product, after start and after finish the measurement period,
total revenues from sales of i product, after start and after finish the
measurement period,
'Z pi1, 'Z pi 2 supplies inventory result of i product, after start and after finish the
measurement period,
i <1, n > reference number of product in the factory’s offer.
As result from the above reasoning, the basic criterion for verifying the structure of
commodity production is maximize total operating profit of the plant and its dynamics in the
analyzed periods of measurement, i.e.:
'Z n t 0
If it is turn out, that permanently (by measuring a significant number of periods:
months, quarters or perhaps years) 'Z n 0 , the commodities affecting negatively the
operating result should be revealed. We ought to aim at eliminating them, because is possible
that the cycle of their life came to an end, if only other important factors do not have an
influence on leaving they in the bid of plant. They may indeed represent such a cost-effective
component in the production of a set of furniture.
The operating profit maximization is proceeding under the influence of conditions
limiting changes the structure of production.
The most important of them:
1. Market capacity:
Pi 2 t Pi1 « Qi
where:
Qi maximum number of i type of product, which finds buyers; is to determine through
market research.
318
2. Production capacity of the i product ( Z di ) :
Pi d Z di ,
and the whole plant:
n
n
i 1
i 1
¦ Pi d ¦ Z di
The fact is, in the event unforeseen circumstances which can cause stoppages in
production or sales, it is necessary to take into account reserve of production capacity, which
is estimating at 15-20%.
Estimating the production capacity of the plant we are usually dealing with some
expensive workplaces which are the proverbial "bottleneck", which they can limit the
production capacity with respect to a particular product. Because of production process, the
expensive work station has to be used. It usually works on more than one shift and the plant's
production capacity can be increased significantly because of that.
SUMMARY
The proposed verification model of the production structure can facilitate the forming
of furniture offer aimed to maximize net operating profit by withdrawals of products, which
the life cycle enters into the decadent phase and as with lapse of time, it will draw to a close.
The detection of this phase may facilitate: the examination of the sales volume of the
given product, lack of price growth below the inflation rate even in a successful phase of the
business cycle, and what is very important, the increase of supplies inventory that product in
the warehouse.
REFERENCES
1. RATAJCZAK E., 2001: Rynek drzewny. Analiza struktur przedmiotowych; Rozprawa
hab. ITD. Pozna , 2001
2. SZCZAWI SKI M., 2004: Efektywno post pu techniczno–ekonomicznego w produkcji
przemys owej; Przemys drzewny nr 1, s. 23-24;
Streszczenie: Metoda weryfikacji struktury asortymentowej produkcji w fabryce mebli
Proponowany model mo e u atwi weryfikacj struktury asortymentowej produkcji przez
uwzgl dnienie zmian kosztu jednostkowego danego produktu, wolumenu jego sprzeda y oraz
cen zbytu w badanych okresach pomiarowych: kszta towanie bardziej op acalnej oferty
rynkowej uwzgl dnia g ówne ograniczenia wzrostu funkcji kryterium ('Z n ) , tj. ch onno ci
rynku oraz zdolno ci produkcyjnej.
Mieczys aw Szczawi ski, Magdalena Olkowicz
Warsaw University of Life Sciences;
Department of Technology, Organisation and Management in Wood Industry;
02-776 Warszawa, Poland
(Ann. WULS – SGGW, For and Wood Technol. 72, 2010)
Application of modified method of beech round wood value pricing
MIECZYS AW SZCZAWI SKI, IZABELLA JENCZYK – TO
OCZKO
Department of Technology, Organization and Management in Wood Industry, Warsaw University of Life
Sciences – SGGW
Abstract: Application of modified method of round wood logs value pricing Valuation of beech logs in unedged
sawnwood processing was made with the use of quantitative data obtained by trail single sawing conducted by
prof. dr hab. W. Dzbe ski and K. Laskowski [Dzbe ski, Laskowski, 2005]. Economic data were taken from the
quarterly “Rynek Drzewny” and together with quantitative data from the trail sawing were the basis for pricing
the value of round wood with the use of proposed formula and methodology. The calculations confirmed the
practical usefulness of the method of raw material in processing valuation. The results showed unsatisfactory
profitability of processing low quality raw material to the standard unedged sawnwood, which was also
influenced by an unfavourable phase of the cycle of market economy.
Keywords: long logs, sawnwood, trial sawing, profitability, wood value.
INTRODUCTION
This article is a continuation of the Group work of the Division of Organisation,
Economics and Designing of Wood Industry Plants (Zak ad Organizacji, Ekonomiki i
Projektowania Zak adów Przemys u Drzewnego) in the statutory research on the topic
"Methods of raw material valuation in the timber processing industry."
Application of proposed formulas and methods of raw materials and wood products
pricing, and discussions on the structure of pricing formulas led to their modification. They
tend to clarify formulas, by taking into account relevant factors affecting the results of the
calculations, such as an inventory-taking difference, finished goods, that express only the
acquirement of materials from wood processing, produced during the analysed period in
comparison with the costs incurred in that phase. The income may in fact contain some stocks
from the previous period as well as part of the production could go into warehouse at the end
of the month. The proposed formula and the method should be applicable to business
activities in wood industry, in which central management is familiar with economic data, that
can be hard to reach (or even impossible to reach) for people outside the company, because of
the trade secret. The data contained in the quarterly "Rynek Drzewny" is valuable and
reliable, but is limited to average values with significant spread. The editorial office of the
quarterly warns against that fact. Therefore, the application of valuation methods cannot
always correspond to the results of calculation of specific companies with different
equipment, technology and production assortment. However application of the method gives
some understanding of the realities of the raw material economy at different stages of cyclical
phase.
1. RESEARCH METHODOLOGY
Round wood value pricing in the processing is reduced to the following formula:
Wi
Ai Bi Ci , whereas:
Ai – discounted value of cash revenue on sales of sawnwood from 1m3 of “i” grade round
wood processing [PLN/m3];
320
Bi – unit costs of transport, raw material sawing and drying of sawnwood together with funds
sunk costs in the operating cycle [PLN/m3];
Ci – unit net income from sale of waste from wood processing [PLN/m3].
2.1. Discounted value of cash revenue on sales of sawnwood from 1m3 of “i” grade round
wood processing is determined by the formula:
Pi r 'Z pk
Ai
(1 r ) d (1 m)Q
, whereas:
Q – volume of raw material sawing covered with the valuation [m3];
r – rate of discount for one day funds sunk received on the basis rate of two-years bonds
(0.048 0.05);
Pi – value of cash revenue on sales of sawnwood from the trail sawing [PLN];
s
Pi
¦T C
ki
k
, whereas:
k 1
Tki – quantity of sawnwood cut from „i” grade logs processing [m3];
Ck – sales price of the “k” assortment of sawnwood from sawing [PLN/m3];
'Z pk - an inventory-taking difference of the “k” assortment of sawnwood [PLN];
m – assumed level of gross profitability from the sale of sawnwood (m = 0, 0.01, 0.05, 0.10);
j 1, o ! - number of days of payment recovery from the sawnwood sale: o=30 is assumed
because of infringement of this term results in the possibility of claim for statutory interest
chargeable on overdue liabilities.
2.2. Unit cost of raw material transport, its sawing and drying, including carrying costs of
capital in operating cycle:
Bi
q1
q2
P r 'Z pk º
ai ª
k
k
k
r
k
k
rd i
0
,
5
(
)
¦
¦
p
s
d
p
s
« t
» , whereas:
a A1 ¬
Q
d 1
d 1
¼
ai – productivity in wood processing in “i” grade;
aA1 – productivity indicator in wood processing of the highest raw material grade;
kt – unit cost of raw material transport to the sawmill [PLN/m3];
kp – unit cost of raw material sawing, recalculated for 1m3 of sawn logs [PLN/m3];
ks – unit cost of sawnwood drying from wood working, recalculated for 1m3 of sawn logs
[PLN/m3];
d 1,q1 , q2 ! - day of the capital commitment in the operating cycle (q1) and sawnwood
storage (q2).
2.3. Net revenue per unit from the sale of waste from processing (with income tax
deducted):
Ci
C0
f (1 ai )C0 , whereas:
U tr (Ctr k0tr ) U zr (C z k0 zr ) - unit gross value from waste sale [PLN/m3];
Utr – share of sawdust;
321
Ctr – selling price of sawdust [PLN/m3];
Uzr – share of chips;
Czr – selling price of chips [PLN/m3];
k0tr – unit cost of providing sawdust to sell [PLN/m3];
k0zr – unit cost of processing waste into chips [PLN/m3];
f – ratio of the company’s share in gross profit, in 2009 f=0.81.
2.4. Figures used in the calculations
2.4.1. Data from the trial sawing
Data obtained from trial sawing, published in the article "Effectiveness of further
sawmill plant processing (a selected example)” in Annals of Warsaw Agricultural University
SGGW. Forestry and Wood Technology, No 56/2005, p. 208-213.
Q=97.64m3 of long logs, from which obtained logs in the following quantities:
QWC(2,3)=74.54m3
QWB(1,2,3)=19.49m3
QWD(2,3)=3.61m3
As a result of trial sawing the following quantities of unedged sawnwood were obtained
(Table 1).
Table 1. Quantity of cut sawnwood obtained from sawing
Timber grade Quantity [m3] Share [%]
T28 I
T28 II
T28 III
T32 III
Total:
21.259
43.795
2.975
4.947
72.976
29.1
60.0
4.1
6.8
100.0
Source: data from trial sawing [Dzbe ski, Laskowski, 2005]
Material efficiency from single sawing is: ai = 72.976/97.64=0.75, ie 75%. Such a high
efficiency from logs sawing results from established saw set. Wastes are recovered in the
form of sawdust in an amount of 1.00-0.74=0.25, ie 25%.
High rate of ai (ai=0.75) has been adopted in the calculations.
Zpk – a sawnwood inventory-taking difference (assuming zero, because of results from the
trial sawing where used);
kt – cost of raw material transport, according to "Rynek Drzewny" data on the basis of which
can be estimated as follows from the relation of 1m3 weight of hardwood and softwood
kt=20PLN/m3*0.7/0.5 28PLN/m3 (Rynek Drzewny, 4/2009);
kp – cost of sawing, kp 220PLN/m3;
ks – cost of drying, ks 192PLN/m3 (Rynek Drzewny, 4/2009);
Ut – share of the sawdust is 100% of waste, results from material efficiency counting from
single sawing;
Ctr – unit selling price of sawdust, maximum value has been adopted, Ctr=30PLN/m3 (Rynek
Drzewny, 4/2009);
k0tr – unit cost of providing sawdust to the sale, estimated at 2 PLN/m3.
322
3. ROUNDWOOD VALUE FROM THE LONG LOGS PROCESSING
3.1. Discounted value of revenues from the sale of sawnwood from trial sawing per 1m3
(Ai)
Table 2 Discounted unit value of revenue from the sale of sawnwood
Discounted net revenue from the sale of
Sawnwood
sawnwood [PLN]
No.
Value [PLN]
Quantity Unit price
Assortment
[m3]
[PLN/m3]
Nominal
Discounted
1
T28 I
21.3
925
19665
19587
2
T28 II
43.8
653
28598
28484
3
T28 III
3.0
425
1264
1258
4
T32 III
4.9
469
2320
2310
Total:
73.0
----------51847
51639
Discounted
revenue per 1m3
of raw material
[PLN/m3]
707
Source: own calculations on the basis of data from trial sawing [Dzbe ski, Laskowski, 2005] and data from
“Rynek Drzewny” No 4/2009.
The data in Table 2 shows that the cost of deferring the payment of consumer’s claims
over allowed one month would be 51847-51639=208PLN, at the processing of 97m3 of round
wood – counted for 1m3 is approximately 2PLN/m3, which is of little value, although, when
sawing of 25 thousand. m3, deferring the payment of consumer’s claims would amount to
about 50 thousand. PLN.
3.2. Unit cost of transport, sawing and drying of sawnwood together with freezing of
capital costs (Bi)
a
Relation of material efficiency i is assumed as 1, because logs of different grades
a A1
were sawn and the Authors did not provide the efficiency of the various grades of logs, giving
a total yield of sawnwood from the entire consignment of long logs. Efficiency in single
sawing of raw material amounted 72.976/97.64 0.75, ie 75%. Results of Bi calculations
contains Table 3.
Table 3. Unit cost of transport for raw material, sawing and drying, taking into account
interest on capital during operating cycle and storage of sawnwood.
Unit costs [PLN/m3 raw material]
Transport
(kt)
28
Sawing
(kp)
220
Sawnwood
drying (ks)
192
Expenses interest
Total:
2
442
The data in Table 3 shows that share of the sawing cost is surprisingly high, and it
seems that cost of drying is real, while the impact of capital interest per 1m3 of wood working
is negligible.
3.3. Unit net revenue on sales of waste from processing (Ci)
323
In the single sawing there are no edgings and slabs, for further chips production, but
only sawdust at a price 30 PLN/m3 and bark of which the value is negligible per 1m3 of raw
material.
Ci
f (1 ai ) Ctr
0,81(1 0,75) 30 # 6 zá m 3 of raw material
3.4. The value of 1m3 of logs (WCO) from the trial sawing, after manipulation into logs
(see p.2.4.1):
As a result of manipulations obtained logs were of various grades, in different market
prices, therefore to compare value of the raw material for the unedged sawnwood processing
with the supply price has been adopted weighted average market price, which is:
74.54 * 231 PLN/m3 + 19.49 * 334 PLN/m3 + 3.61 * 120 PLN/m3 = 17219 + 6310 + 433 =
23962 PLN, ie average price per 1m3 will be: 23962 PLN / 97,64 m3 = 246 PLN/m3.
Calculated values (see p.2.4.1; 3.1; 3.2, 3.3) were used in the computation of raw
material value pricing, and the results are given in Table 4.
Table 4. The value of sawnwood from the trial sawing from the manipulation of the long logs
(WCO).
Net
Cost of
Discounted
Weighted
revenues
transport,
revenues on
average
Accepted Value of raw
on sales of
sawing,
sales of Ai
market price
gross
material
waste (Ci)
drying and
sawnwood per
of raw
margin
Wi=Ai-Bi+Ci
[PLN/m3
interest (Bi)
3
3
1m [PLN/m of
material
[PLN/m3]
(m)
3
of raw
[PLN/m of
raw material]
[PLN/m3]
raw material] material]
0
271
0.01
268
707
442
6
246
0.05
258
0.10
246
Analysis of computation results of round wood (long logs) value shows a satisfactory
profitability of wood processing into unedged sawnwood, because computed wood value was
equal with weighted average price of the raw material at the margin m=0.10, which seems to
be suitable.
SUMMARY
The results of the value calculations of beech round wood long logs (WCO) after
manipulation into logs of different grades (see p.2.4.1) showed a fully satisfactory
profitability of wood processing, because at the assumed margin m=0.10 weighted average
price of the raw material equal with its value, and with less sawmill requirements with
assumptions of the expected margins in the processing, it could pay a bit more for raw
material. By processing beech wood for example on strips sold to the parquetry block factory,
or even manufacture them on site, we can certainly achieve a significantly better financial
results.
324
Influence of capital interest per 1m3 is negligible, but noticeable with considerable
wood processing of the plant (see p.3.1) or recovery of payment extension and storage of
wood materials in anticipation for the buyer.
CONCLUSIONS:
1. Value of beech round wood long logs (WCO) is higher than weighted average market
price of long logs obtained from raw material manipulation in trial sawing. It is equal
at net margin 0.10 in processing.
2. Unedged sawnwood market price provides moderate profitability of beech long logs
processing.
3. Influence of interest of capital frozen in accounts receivable of buyers, as well as in
the stock of sawnwood, is negligible per 1m3 of wood, but with larger quantities of
sawmill scale is noticeable.
4. The results of calculations of the raw material should be treated with moderate caution
due to the spread of data provided by the quarterly “Rynek Drzewny”. Exact
calculation of the raw material value in the processing is possible in a particular plant,
with the use of proposed method.
REFERENCES:
1. DZBE SKI W., LASKOWSKI K., 2005: Effectiveness of further sawmill plant
processing (a selected example). Annals of Warsaw Agricultural University – SGGW.
Forestry and Wood Technology, No 56: 208-213;
2. HRUZIK G., 2001: Efektywno przerobu drewna w ma ych i rednich zak adach
tartacznych. Wood and Paper Review, No 3: 5-7;
3. RATAJCZAK E., 1998: Rynek drzewny: analiza struktur przedmiotowych, Rozprawa
habilitacyjna, Instytut Technologii Drewna, Pozna ;
4. SZCZAWI SKI M., 2008: Warto k ód d bowych w przerobie na deszczu ki
posadzkowe. Drewno, No 180, 117-123;
5. SZCZAWI SKI M., 2009: Formu a rozwini ta rachunku warto ci drewna okr g ego
wg klas jako ci. Drewno, No 181 i 182, 99-104;
6. SZCZAWI SKI M., BIERNACKA J., 2010: Valuation of experimental sawing of
low-grade pine logs (WCO). Intercathedra No 26.
325
Streszczenie: Zastosowanie zmodyfikowanej metody wyceny wartoĞci drewna okrągáego przy
próbnym przetarciu káód z manipulacji dáuĪyc bukowych WCO. Wycena warto ci d u yc
bukowych w przerobie na tarcic nieobrzynan zosta a dokonana z wykorzystaniem danych
ilo ciowych uzyskanych w wyniku próbnego przetarcia na ostro przez prof. dr hab. W.
Dzbe skiego i K. Laskowskiego [Dzbe ski, Laskowski, 2005]. Dane ekonomiczne
zaczerpni te zosta y z kwartalnika Rynek Drzewny i w zestawieniu z danymi ilo ciowymi z
próbnego przetarcia stanowi y podstaw wyceny warto ci drewna okr g ego wed ug
proponowanej formu y i metodyki. Obliczenia potwierdzi y praktyczn przydatno metody
wyceny surowca w przerobie. Wyniki wykaza y niezadowalaj c op acalno przerobu
surowca niskiej jako ci na standardow tarcic nieobrzynan , na co istotny wp yw wywar a
równie niekorzystna faza cyklu gospodarki rynkowej.
Sáowa kluczowe: d u yce, tarcica, próbne przetarcie, op acalno , warto
Mieczys aw Szczawi ski
02-776 Warsaw,
Izabella Jenczyk - To oczko
02-776 Warsaw,
drewna.
Natural resistance of selected South-East Asian wood species against
Gloeophyllum sepiarium (Wulf. Fr.) P. Karst fungus
MAGDALENA SZCZ SNA, BOGUS AW ANDRES, MICHA KOSTYRA
Department of Wood Science and Wood Protection, Warsaw University of Live Science - SGGW
Abstract: Two wood species originating South-East Asia were tested against natural resistance to destructive
fungi. In aim to determine wood natural resistance to fungi mass loss and corresponding durability grades
Highest grade was reached by Shorea laevis Ridl. Slightly lower Gloeophyllum sepiarium (Wulf. Fr.) P. Karst
fungi resistance was shown by Shorea acuminata Dyer. wood.
Keywords: exotic wood species, natural resistance, Gloeophyllum sepiarium (Wulf. Fr.) P. Karst, Shorea laevis
Ridl., Shorea acuminata Dyer.
INTRODUCTION
Exotic wood is nowadays widely used in many areas. Exotic species coming from
tropical areas show very good physical and mechanical properties, and good resistance to
biodegradation. For this reason, exotic wood is frequently used in external conditions.
In constructional wood and wooden elements expose to outdoor conditions, most
likely, decay occurs. Process taking even several years may lead to serious and extensive
construction damage. Fungi causing wood decay thru cellulose degradation significantly
decrease most of the mechanical properties of wood. It is determined that amongst many
fungi species growing on wood only 6% cause advanced decay (Krajewski and Witomski,
2005). One of the most common decaying fungi is Gloeophyllum sepiarium, attacking
outdoor wood, especially in buildings and smaller elements. Commonly present in the
engineering constructions, such as bridges, towers, telegraph poles, sleepers, garden
architecture and storage yards. Described fungi is also present in the constructional elements:
floor joists, rafter framings, external walls, post and pan walls, terraces and loggias.
Due to increasing number of exotic wood species on the market, especially ones with
similar colors, it is necessary to determine which species could prove to be useful in particular
applications. Good example of the research on this topic is determination of decaying fungi
influence on wood durability.
Aim of the presented work is to determine natural resistance of Shorea laevis Ridl. and
Shorea acuminata Dyer., against decaying fungus. Selected Gloeophyllum sepiarium (Wulf.
Fr.) P. Karst fungi species is not included in the PN-EN 350-1:2000 standard.
Methodic applied in the work was corresponding to instructions of PN-EN 350-1:
2000 and PN-EN 113 + A2: 1993 standards. Two originating from South-East Asia species
were tested: Shorea laevis Ridl. and Shorea acuminata Dyer. Each species was cut into 50 x
25 x 15 mm samples (40 pieces, first dimension along the grain). In the same manner control
samples of Fagus sylvatica L. were prepared, according to PN-EN 350-1:2000 standard.
Exotic and control samples were exposed to Gloeophyllum sepiarium (Wulf. Fr.) P. Karst
fungi during the 12 weeks period. For decaying power test of the fungi beech wood was used.
The only exception from the standard was usage of the G. sepiarium fungi, which can be
hazardous to the wood, in dependence of the environment conditions.
327
RESULTS
Work assesses G. sepiarium fungi influence on the wood, by determination of mass
loss caused by the microorganisms during 12 weeks period. Independently on the species
resistance loss was noticed.
Considering G. sepiarium fungi on mass loss, one may conclude that exotic wood
showed more resistance than local wood (table 1) . Amongst tested species Shorea laevis
Ridl. Showed best results, with mass loss of only 0,50%. Less resistance, resulting with
4,47%, was shown by Shorea acuminata Dyer wood. Highest mass loss of 7,56% was shown
by local Fagus sylvatica L.
Table 1. Mass loss caused by Gloeophyllum sepiarium fungus influence
Average mass
Wood species
initial
final
[g]
Average
mass loss
Standard
deviation
[%]
[g]
Shorea laevis Ridl.
15,44
15,36
0,50
0,32
Shorea acuminata Dyer.
9,00
8,57
4,47
0,30
Fagus sylvatica L.
11,83
10,82
7,56
3,7
Basing on the mass loss caused by G. sepiarium, exotic wood fungi resistance may be
described as high, which is caused by fungistatic substances naturally present in the wood and
high density.
Mass loss caused density change, which is presented in table 2 and on figure 1. after
12 weeks exposure to fungi density dropped in each case. Highest density drop of 8,6%, was
shown by Fagus sylvatica L. For Shorea acuminata Dyer. wood density was lowered by
4,7%, nearly half of the control samples results. Lowest density drop was shown by Shorea
laevis Ridl. (0,5%).
Table 2. Density loss caused by Gloeophyllum sepiarium fungus
Average density
Wood species
initial
final
[kg/m3]
Shorea laevis Ridl.
Fagus sylvatica L.
852
472
662
328
848
450
605
8,6
Density loss [%]
9,00
8,00
7,00
6,00
4,7
5,00
4,00
3,00
2,00
0,5
1,00
0,00
Shorea laevis Ridl.
Fagus sylvatica L.
Figure 1. Density loss caused by Gloeophyllum sepiarium fungus
According to Cartwright and Findlay (1951) decay caused by fungi may lead to 30 %
mass loss of undurable wood. In case of tested species total mass los may reach only around
5%. Therefore in classification proposed by Cartwright and Findlay (1951) all species tested
in his work may be graded as durable. Extended resistance of tested species is caused by toxic
substances present in the wood, having protective properties. Exotic wood in many cases has
high density, rendering penetration by fungi difficult.
Basing on the presented data, one may conclude that tested exotic species hale high
natural resistance, exceeding local species, against biological corrosion.
Obtained results allow classification of tested species into natural durability grades.
Highest resistance is shown by Shorea laevis Ridl. It was graded into highest 1st class of
resistance against G. sepiarium fungus. Shorea acuminata Dyer. was graded into 3rd
resistance class. Obtained results are comparable to data presented by PN-EN 350-2:2000
standard. For Shorea acuminata Dyer. wood it is 3rt-4th durability class and for Shorea laevis
Ridl. 2nd class of Trametes versicolor L. fungus resistance.
CONCLUSION
Basing on the presented data, one may conclude:
1. Highest durability grade amongst tested South-East Asian species against G.
sepiarium fungus, was shown by Shorea laevis Ridl. wood. It was graded into 1st class
of natural durability.
2. Shorea acuminata Dyer. wood was graded into 3rd natural durability class against G.
sepiarium fungus.
3. In case of both tested exotic species G. sepiarium fungus caused lower mass loss than
in case of local Fagus silvatica L wood.
4. Shorea laevis Ridl. wood is more appropriate to be used in outdoor conditions than
Shorea acuminata Dyer. wood.
329
REFERENCES:
1. CARTWRIGHT K.ST., FINDLAY W.P.K., 1951: Rozk ad i konserwacja drewna.
PWRiL. Warszawa.
2. KRAJEWSKI A, WITOMSKI P., 2005: Ochrona drewna surowca i materia u,
Wydawnictwo SGGW, Warszawa
3. PN-EN 113 + A2: 1993 rodki ochrony drewna. Oznaczanie warto ci grzybobójczej
wobec rozk adaj cych drewno grzybów Basidiomycetes hodowanych na po ywce
agarowej.
4. PN-EN 350-1:2000 Trwa o drewna i materia ów drewnopochodnych – naturalna
trwa o drewna litego. Cz
1: informacje o zasadach badania i klasyfikacji
naturalnej trwa o ci drewna.
5. PN-EN 350-2:2000 Trwa o drewna i materia ów drewnopochodnych – naturalna
trwa o drewna litego. Wytyczne dotycz ce naturalnej trwa o ci i podatno ci na
nasycanie wybranych gatunków drewna maj cych znaczenie w Europie.
Streszczenie: Badanie naturalnej odpornoĞci wybranych gatunków drewna pochodzących z
Azji Poáudniowo-Wschodniej na dziaáanie grzyba Gloeophyllum sepiarium (Wulf. Fr.) P.
Karst. Dwa gatunki drewna, pochodz ce z Azji Po udniowo-Wschodniej, poddano badaniu
naturalnej trwa o ci wobec grzyba, powoduj cego brunatny rozk ad drewna. W celu
okre lenia odporno ci na dzia anie tego mikroorganizmu okre lono zmiany g sto ci, ubytek
masy po 12. tygodniowym okresie ekspozycji na dzia anie grzyba, oraz ustalono klas
naturalnej trwa o ci. Wykazano, e najwy sz klas naturalnej trwa o ci spo ród badanych
gatunków drewna, charakteryzuje si Shorea laevis Ridl. (1 klasa). Drewno Shorea
acuminata Dyer. zosta o zakwalifikowane do 3 klasy naturalnej trwa o ci wobec ataku ze
strony grzyba Gloeophyllum sepiarium (Wulf. Fr.) P. Karst.
Magdalena Szcz sna
Bogus aw Andres
Department of Wood Sciences and Wood Protection,
02-776 Warsaw,
Poland
(Ann. WULS-SGGW, For. And Wood Technol., 72, 2010)
Examination of common ash (Fraxinus excelsior L.) colour change after
heat treatment
MAGDALENA SZCZ SNA, JAKUB GAWRON, TOMASZ ZIELENKIEWICZ
Department of Wood Science and Wood Protection, Faculty of Wood Technology, Warsaw University of Life
Science – SGGW
Abstract: The aim of this work was to specify colour change in common ash wood (Fraxinus excelsior L.) after
heat treatment. It was performed in steam or in the air with different durations (2, 6, 10h), in the temperature of
190oC. Darkening of ash wood increases with the treatment duration. Colour significantly depends on the
treatment conditions – ash wood treated in steam is lighter in relation to samples treated in the air.
Keywords: wood colour, L*a*b* system, heat treatment, ash wood
INTRODUCTION
Market of heat treated wood intensively developes in Europe as well as in the rest of
the world. New factories arise which specialize in manufacture of heat treated wood both in
the raw state and in the form of finished products such as parquets, facades and plywood.
Different manufacturers elaborated their own treatment processes suitable to specific wood
species and final product.
Heat treatment should be performed in the oxygen-free environment what protects
wood against exvessive degradation during process. Treatment environments, which are most
often applied, are: steam, nitrogen, oil, exhaust gas, at the action of high temperature in the
range of 160-230oC (Hill, 2006).
Natural wood durability, hardness and dimensional stability increase as the result of
heat treatment of wood (Sivonen et al., 2002). Decrease of equivalent moisture level is an
additional effect. Changes mentioned above are most probably caused by hemicelluloses
decomposition to monosaccharides (Yildiz, 2006), partial degradation of cellulose with low
polimerisation degree and the increase of crystallinity degree of cellulose with high
polimerisation degree (Gawron et al., 2009; Yildiz & Gumukaya, 2007).
Apart from apllied processing parameters, one of the most important attribute of
treated wood is the change of its colour. Wood darken during heat treatment process and may
imitate exotic wood. Properly performed heat treatment causes the colour change in whole
wood section. Darkening process can be controlled to obtain required shade, from light to
very dark. This is determined by the duration and temperature of treatment process.
Despite the progress in analysis of physical and mechanical properties of wood treated
by heat, there are no complex researches related to these properties. The purpose of this paper
is to determine the colour changes which take place in the common ash wood (Fraxinus
excelsior L.) after heat treatment in steam and air (to emphasise the colour change), different
durations (2, 6, 10h), at the temperature of 190oC.
The heat treatment program applied in current paper is based on the process elaborated
by FINFOREST company. Treatment parameters were selected in order to make them
compatible with conditions recommended and most often used in the polish marked for ash
wood.
Analysed samples were gained from the coloured part of ash heartwood (Fraxinus
excelsior L.). 224 samples (20x20x30 mm) were cut from one board. They were sorted by
331
density and divided into 7 groups of 32 samples. 3 groups were treated with the oxygen acces,
in the temperature of 190oC, duration 2, 6 and 10 h. Following 3 groups were treated in steam
in the temperature of 190oC, duration 2, 6 and 10 h.
Process started in each case from samples drying to absolute humidity 0%. Then the
temperature in the treatment chamber with samples was raised to assumed value of 190oC
with the heating rate of 0,4oC/min. Time of specific treatment was started one hour after
riching the assumed temperature. In case of the treatment in steam, the steam was introduced
to the chamber in the temperauture of 130oC. Course of treatment process is illustrated in the
fig. 1.
205
Treatment temperature/°C
190
175
160
145
130
115
100
85
0
120
240
360
480
600
720
840
960
1080 1200 1320 1440 1560
Time/min
Figure 1. Course of treatment process.
Samples were cooled after heat treatment and seasoning within one month in normal
atmospheric conditions, but without sunshine access. X-Rite SP-60 compact spherical
spectrophotometer was applied to colour specification. Colour was described in L*a*b*
system. Colour index was calculated basing on components:
xtotal colour difference, from the equation:
'E *ab
[('L*) 2 ('a*) 2 ('b*) 2 ]1 / 2 , where
'L*
L *T L * R - brightness difference
'a*
a *T a * R - red colour difference (a>0)
'b* b *T b * R - yellow colour difference (b>0)
xchromaticity (colour saturation) from the equation:
C *ab
( a * b * ) 1 / 2 2
2
332
x shade, from the equation:
H*
arctg (b * / a*)
Mean values were calculated from obtained results (5 measurements on one sample).
There have not been any standard defining the way of wood colour change analysis until now.
That is why following standards were exploited: PN-ISO 7724-1:2003 Paints and laquers Colorimetry – Part 1: Basics, PN-ISO 7724-2:2003 Paints and laquers - Colorimetry – Part 2:
Colour specification, PN-ISO 7724-3:2003 Paints and laquers - Colorimetry – Part 3: Colour
differences calculation.
RESULTS
Table 1 presents data obtained for individual types of wood treatment. Heat treatment
causes significant colour change both in steam environment and with oxygen acces, what
arises from colour coordinates analysis. Brightness value decrease with treatment time, what
means wood darkening. Colour of samples treated 10 hours with oxygen acces (in the air)
changed most significant (brightness mean value L*=39,13). Samples treated in the steam
environment are a bit lighter (brightness mean value L*= 43,67). Also for 6 and 2 hours
duration samples after treatment in the steam are lighter than ones treated in the air.
Shade
(H*)
Chromaticity
(C*)
Brightness (L*)
Table 1. Colour characteristics of wood untreated and treated in the air and steam environment.
Wood treated with oxygen
Wood treated in steam
Colour
Untreated
access
characteristic
wood
2h
6h
10h
2h
6h
10h
59,81
34,08
34,08
35,54
45,84
42,3
35,64
L*min
L*mean
71,59
45,00
40,81
39,13
51,32
48,9
43,67
L*max
83,57
78,16
47,58
42,92
61,48
53,65
51,12
s*
3,36
5,41
3,12
2,08
4,02
3,27
3,68
v**/%
4,70
12,01
7,65
5,31
7,83
6,80
8,42
C*min
17,65
16,65
9,7
13,77
22,61
19,01
13,34
C*mean
22,36
22,72
18,27
16,87
25,62
22,61
19,63
C*max
27,11
27,48
75,01
20,75
28,67
25,7
24,32
s*
1,68
2,46
3,13
1,81
1,83
1,99
2,62
v**/%
7,52
10,82
17,12
10,73
7,13
8,79
13,33
H*min/o
68,54
69,70
65,64
68,35
73,3
72,18
69,51
H* r/o
75,82
73,53
71,32
71,04
75,49
74,59
73,08
H*max/o
83,19
75,83
75,01
72,77
78,16
76,38
75,92
s*
4,06
1,30
1,71
1,00
1,24
1,06
1,30
v**/%
5,35
1,77
2,39
1,41
1,64
1,42
1,78
*- standard deviation
** - variation coefficient
Two residual colour characteristics (chromaticity and shade) also change after heat
treatment. These changes are insignificant but increasing with the treatment time. Value of
shade decreased from 75,82o to 71,04o (in the air) and 73,08o (in the steam). Our results show
that ash colour shade is not pure yellow, but more yellow than red (angle close to 90o
indicates yellow shade, close to 0o or 360o – red shade).
333
Criterion used by International Commission of Illumination (CIE) was applied.
According to this criterion, total colour difference E* are classified, which are adequate to
human colour perception. It is assumed that colour difference between 0 and 2 is not
recognizable, from 2 to 3,5 – recognizable by inexperienced observer, values above 3,5 mean
the observable significant colour deviation. All of our treated samples significantly differs
from untreated ones in respect of colouring. Colour difference of wood treated with the
oxygen access is slightly higher in relation to wood treated in the steam environment (fig. 2).
Wood treated with oxygen access
Wood treated in steam
35
Total colour difference
30
25
20
15
10
5
0
2
6
Treatment duration/h
10
Figure 2. Total colour difference of wood treated in the air and the steam in relation to untreated samples.
CONCLUSION
Applied method of heat treatment causes colour change, apart from process
parameters. Samples darkening takes place and its intensity increases with treatment time.
Apart from process duration, samples treated in steam are lighter in relation to wood treated
with the oxygen acces.
REFERENCES
1. GAWRON J., GRZE KIEWICZ M., ZAWADZKI J., ZIELENKIEWICZ T., 2009:
Wp yw modyfikacji termicznej w przegrzanej parze wodnej drewna buka
zwyczajnego (Fagus silvatica L.) na zawarto polisacharydów. Ann. of Warsaw
Agricult. Univ-SGGW, For. And Wood Technol. 68, 270-273.
2. HEIDELBERG – Anonim, 1999: Barwa i jako . Heidelberg Druckmaschinen AG,
Kurfursten-Anlage, 52-60.
3. HILL C., 2006: Wood Modification Chemical Thermal and Other Processes. WileyBlackwel.
4. SIVONEN, H., MAUNU, S.L., SUNDHOLM, F., JÄMSÄ, S., VIITANIEMI, P., 2002:
Magnetic Resonance Studies of Thermally Modified Wood, Holzforschung, 56, 648-
334
654.
5. YILDIZ S., GEZER E.D., YILDIZ U., 2006: Mechanical and chemical behavior of
spruce wood modified by heat. Sciece Direct, Building and Environment 41,17621766
6. YILDIZ S., GUMUKAYA E., 2007: The effects of thermal modification on crystalline
structure of cellulose in soft and hardwood. Building and Environment 42, 62–67
7. PN-ISO 7724-1:2003 Farby i lakiery – Kolorymetria – Cz
1: Podstawy.
2: Pomiar barwy.
3: Obliczanie ró nic
barwy.
Streszczenie: Badanie zmian barwy drewna jesionu wyniosáego (Fraxinus excelsior L.) poddanego
modyfikacji termicznej. Próbki drewna jesionu wynios ego, pozyskanych z zabarwionej cz ci
twardzieli, poddano modyfikacji 2-, 6- i 10-godzinnej w rodowisku pary wodnej i z dost pem tlenu w
temperaturze 190 C. Do pomiarów barwy wykorzystano kompaktowy spektrofotometr sferyczny SP60, firmy X-Rite. Wykazano, e proces termicznej obróbki drewna powoduje zmian kolorystyki tego
materia u. Najwi kszym pociemnieniem barwy charakteryzuje si drewno po 10-godzinnej, nast pnie
po 6- i 2-godzinnej modyfikacji, z tym, e drewno znajduj ce si w rodowisku pary wodnej przybiera
nieco ja niejsz barw , ni drewno poddane obróbce termicznej z dost pem tlenu.
Magdalena Szcz sna
Jakub Gawron
Tomasz Zielenkiewicz
Department of Wood Sciences and Wood Protection,
Ul. Nowoursynowska 159,
02-776 Warsaw,
Poland
Interactions of silicon compounds and mixture of linseed and tung oils
with cellulose
KINGA SZENTNER1, IZABELA RATAJCZAK1,
BART OMIEJ MAZELA2, PATRYCJA HOCHMA SKA2
1
Pozna University of Life Sciences, Department of Chemistry, Wojska Polskiego 75, PL-60625 Poznan, Poland
Pozna University of Life Sciences, Institute of Chemical Wood Technology, Wojska Polskiego 38/42,
PL-60637 Poznan, Poland
2
Abstract: Reactivity of cellulose with a formulation containing organosilanes and natural oil was analysed in
order to determine the practical influence of the treatment on biological properties of wood. Structural analysis
of cellulose after the reaction with organosilanes and after extraction was performed using FTIR spectroscopy. In
FTIR spectra the analyzed bands included 800 cm-1 responsible for vibrations of SiC and/or SiO groups. These
bands are characteristic of silicon bonds with atoms of carbon and oxygen originating from the methoxy groups
found in organosilanes. The presence of these bands in the spectra proves the occurrence of a reaction between
cellulose and organosilanes.
Keywords: silicon compounds, MTMOS, NOTES, FTIR spectroscopy
INTRODUCTION
Treatment with coatings based on natural oil modified with silicon compounds
considerably diminishes water uptake of wood. Structural analysis of bonds between wood
basic chemical compounds and silicon compounds can determine developed structures,
explain chemical reactions, thus proving the effectiveness of silicon compounds as agents
enhancing wood properties. Donath et al. [2007] treated wood with alkoxysilanes and other
organofunctional silanes. The method relies on hydrolysis of alkoxysilanes and a subsequent
condensation of silanol groups formed within the porous wood surface. It was shown to be an
effective method to reduce water uptake of wood after cyclic water immersion and drying
exposure. The enhanced dimensional stability observed after these treatments is due to the
replacement of hydrophilic hydroxyl groups with hydrophobic substances.
In this study we used cellulose fibers as the organic component. Cellulose is an
extraordinary renewable polysaccharide with unique properties. Because of its abundance,
biodegradability, and remarkable properties, it has been widely exploited as a source of
materials, either close to its native form or after appropriate chemical modifications [Cunha et
al. 2010]. The preparation of organic-inorganic hybrid materials combining polysaccharides,
such as cellulose with silicon compounds, has only been reported within the last decade
[Tanaka and Kozuka 2004, Maeda et al. 2006, Sequeira et al. 2007]. In the present article we
have stated that it would be more effective, in comparison with the above approaches, to use
film-forming polymersilane hybrid coatings specifically formulated to provide enhanced
adhesion to cellulose and wood structural constituents and moisture barrier properties. The
key advantage of using a combination of resin and silane rather than silane alone is that silane
films are known to exhibit relatively poor moisture barrier properties and tend to be very thin,
and therefore not very durable unless topcoated.
The reaction of organosilane preparation solutions (methyltrimethoxysilane (MTMOS,
CH3Si(OCH3)3); N-Octyltriethoxysilane (NOTES, C14H32O3Si) with a mixture of linseed and
tung oils in an organic solvent was run at room temperature at different volumetric ratios.
Reactions of cellulose of Merck with silane preparations (1/25 w/v) were run at room
336
temperature at the simultaneous stirring with a magnetic bar stirrer for 2 h. Samples were left
at room temperature for 2 h and next filtered. They were left to dry at room temperature. The
obtained materials were eluted using continuous extraction with deionized water at a constant
ratio (1/100 w/v) for 2 h.
Infrared Spectroscopy
Cellulose samples were mixed with KBr at a 1/200 mg ratio. Spectra were registered
using an Infinity spectrophotometer by Mattson with Fourier transform at a range of 500-4000
cm-1 at a resolution of 2 cm-1, registering 64 scans.
Figure 1 presents FTIR spectra of cellulose following a reaction with organosilane
solutions (MTMOS/NOTES) and a mixture of linseed and tung oils, while fig. 2 – those of
cellulose after the reaction and elution (after water extraction).
We need to stress here the fact that after the reaction a new band of 1750 cm-1 was found in all
cellulose spectra, responsible for stretching vibrations of the C=O group. The presence of this
band indicates the conversion of cellulose with natural oil and in the system with
organosilanes (fig. 1). This band is visible also on IR spectra after extraction (fig. 2), which
indicates a permanent bond of natural oil with cellulose.
Fig. 1. IR spectra of cellulose (A), cellulose after reaction with mixture of linseed and tung oils (VEOPOL) 10%
and MTMOS/NOTES (2.5%) (B), VEOPOL 20% and MTMOS/NOTES (2.5%) (C), VEOPOL 10% and
MTMOS/NOTES (5%) (D), VEOPOL 20% and MTMOS/NOTES (5%) (E)
In spectra (fig. 1) of cellulose following the reaction with preparations of a mixture of
linseed and tung oils/organosilanes a band of 800 cm-1 characteristic of Si-C and/or Si-O
bonds was recorded. This band is found also in cellulose spectra after extraction (fig. 2). They
are bands characteristic of a silicon bond with carbon and oxygen atoms originating from the
methoxy group present in organosilanes [Ghosh et al. 2009; Tingaut et al. 2005, 2006;
Tjeerdsma, Millitz 2005].
337
Fig. 2. IR spectra of cellulose after extraction: cellulose (A), cellulose after reaction with mixture of linseed and
tung oils (VEOPOL) 10% and MTMOS/NOTES (2.5%) (B), VEOPOL 20% and MTMOS/NOTES (2.5%) (C),
VEOPOL 10% and MTMOS/NOTES (5%) (D), VEOPOL 20% and MTMOS/NOTES (5%) (E)
A confirmation for the reactivity of organosilanes with cellulose comes from the
results of atomic absorption spectrometry. The highest values of silicon concentration in
cellulose, amounting to 1235 mg/kg, were recorded after a reaction with a 20% natural oil
solution and a 5% mixture of MTMOS/NOTES.
A marked difference was also observed in the degree of reactivity of cellulose with
MTMOS and NOTES (at all analyzed concentrations) in comparison to a MTMOS/NOTES
organosilane mixture, to the advantage of the latter system. We need to particularly stress the
fact that the level at which silicon concentration was determined in cellulose after water
extraction, in comparison to the level of silicon concentration in cellulose after the reaction
with all organosilanes, was only slightly lower.
CONCLUSIONS
In FTIR spectra the presence of bands characteristic of vibrations of the silicon-carbon
and silicon-oxygen bonds, coming from the SiC and SiO groups at 800 cm-1, from
organosilane solutions shows that a chemical reaction has occurred between cellulose and
organosilanes (particularly a MTMOS/NOTES mixture). The presence of bands responsible
for vibrations of the SiOCH3 group on IR spectra of cellulose after reaction and extraction
proves a permanent character of the formed bond between the hydroxyl and methoxy groups
of organosilanes. The silanol groups formed after hydrolysis of the alkoxy groups of the
silanes can react with hydroxyl groups of cell wall polymers. However, these Si-O-C bonds
are susceptible to hydrolysis. The high concentration of silicon determined in cellulose and in
wood powder after extraction in comparison to the high silicon concentration in cellulose and
wood powder after a reaction with organosilanes (particularly in case of the application of a
MTMOS/NOTES organosilane mixture) confirms the permanent character of the bond
between cellulose or wood powder and the analyzed preparations.
338
ACKNOWLEDGEMENT
The study was funded by the research project (NN 309071736) from the Ministry of Scientific Research and
Information Technology.
REFERENCES
1. S. DONATH, H. MILITZ, C. MAI Weathering of silane treated wood. Holz Roh.
Werkst. 65 (2007) 35-42.
2. A. CUNHA, C. FREIRE, A. SILVESTRE, C. NETO, A. GANDINI Preparation and
characterization of novel highly omniphobic cellulose fibers organic-inorganic hybrid
materials. Carbohydrate Polymers 80 (2010) 1048-1056.
3. K. TANAKA, H. KOZUKA Sol-gel preparation and mechanical properties of
machinable cellulose/silica and polyvinylpyrrolidone/silica composites. Journal of
Sol-Gel Science and Technology 32 (2004) 73-77.
4. H. MAEDA, M. NAKAJIMA, T. HAGIWARA, T. SAWAGUCHI, S. YANO
Bacterial cellulose/silica hybrid fabricated by mimicking biocomposites. Journal of
Materials Science 41 (2006) 5646-5656.
5. S. SEQUEIRA, D.V. EVTUGUIN, I. PORTUGAL, A.P. ESCULCAS Synthesis and
characterization of cellulose/silica hybrids obtained by heteropoly acid catalysed solgel process. Materials Science and Engineering C (27) (2007) 172-179.
6. S.C. GHOSH, H. MILITZ, C. MAI The efficacy of commercial silicones against blue
stain and mould fungi in wood. Eur. J. Wood Prod. 67 (2009) 159-167.
7. P. TINGAUT, O. WIEGENAND, C. MAI, H. MILLITZ, B. DE JÉSO, G. SÈBE
Functionalisation of wood by reaction with 3-isocyanatopropyltriethoxysilane:
Grafting and hydrolysis of the triethoxysilane end groups, Holzforschung 59 (2005)
397-404.
8. P. TINGAUT, O. WIEGENAND, H. MILLITZ, G. SÈBE Chemical reaction of
alkoxysilane molecules in wood modified with silanol groups, Holzforschung 60
(2006) 271-277.
9. B.F. TJEERDSMA, H. MILLITZ Chemical changes in hydrothermal treated wood:
FTIR analysis of combined hydrothermal and dry heat-treated wood, Holz a Roh u
Werkst 63 (2005) 102-111.
Streszczenie: Wzajemne odziaáywanie związków krzemoorganicznych, mieszaniny olejów
lnianego i tungowego z celulozą. Praca mia a na celu zbadanie reaktywno ci celulozy z
nowymi preparatami krzemoorganicznymi z udzia em oleju lnianego i tungowego. Analiz
strukturaln celulozy po reakcji z organosilanami oraz po ekstrakcji wykonano metod
spektroskopii w podczerwieni (FTIR). Przedstawione wyniki analizy strukturalnej
modyfikowanej celulozy organosilanami wskazuj na ich wysok reaktywno z celuloz .
Zarejestrowane pasma absorpcji w widmach IR modyfikowanej celulozy organosilanami jak i
po ekstrakcji w zakresie 1235 cm-1 s odpowiedzialne za drgania grupy SiC oraz 800 cm-1 s
odpowiedzialne za drgania grup SiC i/lub SiO. Pasma te zarejestrowane w widmach IR
modyfikowanej celulozy organosilanami s charakterystyczne dla wi zania krzemu z atomem
w gla i tlenu pochodz cym od grupy metoksylowej obecnej w organosilanach. Obecno tych
pasm w widmie wiadczy o zaj ciu reakcji mi dzy celuloz a organosilanami.
Izabela Ratajczak
Poznan University of Life Sciences
Department of Chemistry
Wojska Polskiego 75, PL-60625 Poznan, Poland
Interrelationships between cutting force and tool wear in chipboard milling
KRZYSZTOF SZWAJKA1), JOANNA ZIELI SKA-SZWAJKA 1)
1)
Abstract: Wear of a cutting edge in end-milling is a complicated process that requires a reliable technique for in
process monitoring and control of the cutter performance. This paper presents an approach to examine the effect
of wear variation on the magnitude of the cutting force harmonics. The results were plotted in time and
frequency domains. Cutting forces in process milling were measured using highly sensitive dynamometer which
was calibrated in static and dynamic ranges. The tool wear was measured in an off-line manner and
interrelationships of cutting force harmonics and tool wear magnitude were constructed. Hence a cutter wear
monitoring strategy is constructed.
Keywords: milling, chipboard, cutting force, force sensor
INTRODUCTION
In the study of the relationship between the cutting force harmonics and cutting tool
flank wear of a cutting edge in end-milling. Bamdyopadhay et al. [1], found that the
amplitude of the dynamic components of the cutting signal are continuously decreasing up to
the deterioration stage of the tool flank wear. Lee et al. [2], found that the dynamic
components are sharply decreasing at the onset of the accelerated wear zone after a earlier
increase. While Zhang and coworkers [3], Elbestawi et al. [4], found that the dynamic cutting
components are continuously increasing. The production of an industrial product with high
accuracy and surface quality requires control of the tool performance. The development of a
fully automated machining system is a practical method to sense the amount of tool wear.
Such a development would enhance the quality of the product by insuring that surface and
geometrical specifications are within tolerance. In addition, there would be decrease in cutting
times, and savings in tool changing times. All of which could result in an estimated overall
savings of up to 40% [4]. There are two techniques for tool wear sensing: direct and indirect.
The direct technique includes measuring the actual wear, using radioactive analyses of the
chip. Indirect technique includes measuring of cutting forces, torque, vibration, acoustic
emission (stress wave energy), sound, temperature variation of the cutting tool, power or
current consumption of spindle or feed motors and roughness of the machined surface [4-7].
In this study, the cutting forces are used as the indicator of the tool flank wear variation.
Finally an on-line flank tool wear monitoring system is constructed.
CUTTING FORCE IN PROCESS MILLING
Investigation of milling process from cutting force point of view begins in year 1941
by M. E. Martellotti and Cincinnati Milling Machine Company. Ten years later (1955) R
Pickenbrick investigates cutting forces during face milling. In 1961 Koenigsberger and
Sabberwal investigated frequency of cutting forces during face milling with three components
dynamometer. Rapid development of measuring instrumentation and computers, in 70 ties
investigations rapid increased. Because face milling process is one of the most often used and
the most efficient process among high productive machining processes it is logically that the
most of the papers and investigations are connected with this machining process. Cutting
forces during face machining are investigated intensively analytically and experimentally.
Some of previous approaches to cutting forces determination consider only main (tangential)
cutting force component, and according this define cutting power. Later attempt consider
other cutting force components also. Face milling process particularity like multi tooth that
simultaneously cutting and difference in chip cross section that one tooth cut influenced
340
development of variety of models for cutting force calculation. Variation in chip cross section
gives difference in intensity of cutting forces and thermal load of single tooth. For easier
cutting force model definition usually is considered case
of one tooth milling cutter cutting and cutting width is
equal to cutter diameter D. In this case chip cross section
is like it is shown on Fig 1.
Ft
Fx cosM F y sinM
(1)
Fr Fx sinM F y cosM
(2)
where:
ĳ-rotation angle, Ft and Fr tangential and radial components of the
cutting force, Fx and Fy cutting forces in X-, Y directions.
The forces are oriented as follows: the "tangential force"
is oriented along the feeding direction and has its positive
versus in the cutting direction; the "radial force" is
oriented perpendicularly to the feeding direction and its verse is positive going inside the
surface. Both parallel and normal force are in the same horizontal plane.
Fig. 1. Cutting forces in milling
FAST FOURIER TRANSFORM (FFT)
An energy-limited signal f(t) can be decomposed by its Fourier transform F( ), namely
f (t )
F( Z )
1
2S
f
³ F( Z ) e
j Zt
dZ
(3)
f
f
³ f (t )e
j Zt
dt
(4)
f
f(t) and F( ) are known as a pair of Fourier transforms. Equation (2) implies that f(t) signal
can be decomposed into a family with harmonics ej t and the weighting coefficient F( )
represent the amplitudes of the harmonics in f(t). F( ) is independent of time, it represents the
frequency composition of a random process, which is assumed to be stationary so that its
statistics do not change with time. Fourier transform has been successfully used to process the
AE signal during turning. In [1], experimental results have shown that the magnitude of the
AE in the frequency domain was sensitive to the change of tool state. However, the vibration
signal is essentially non-stationary. If we calculate the frequency composition of
nonstationary signals by using Fourier transform, the results are the frequency composition
averaged over the duration of the signal. As a result, Fourier transform cannot describe
adequately the characteristics of the transient signal in the lower frequency.
EXPERIMENTAL TEST
The experiments have been performed on the milling center Busellato JET 130.
Fig. 2. Milling machine Buselatto JET 130 and tri-axial dynamometric piezoelectric platform
341
In experiments was used based-wood materials-laminated chipboard. Dimensions of the
specimens which were prepared for the machining were as follows: 900x30x18mm (Fig. 2).
The cutting tools was a DIMAR HW I12 x 51. In research applications four cutting tools (Test
K1-K4). The feed speed were constant(11m/min) and the spindle speed was constant
(18000min-1). The signals were digitized and stored into a computer using a Computer Boards
NI PCI-6111E analog-to-digital converter. The piezoelectric sensor Kistler 5034A3 was
clamped between two plates (Fig. 3). VBmax was selected as the tool wear measure. The
original (Fx and Fy) signals were recorded on a hard disk PC in a digital form. In the course of
breaks executable measurements VBmax with the of workshop microscope.
Fig. 3. Multi-component quartz force sensor KISTLER 9601A3, charge amplifier KISTLER 5023A3 and
piezoelectric sensors clamped between two plates
The forces acting on the dynamometer were averaged in the time domain while resultant
cutting force (FRR) acting on the cutter was calculated by:
Fx2 Fy2
FRR
(5)
where:
FRR resultant force, Fx and Fy cutting forces in X-, Y directions.
The literature data concerning the use of spectral analysis to assess the technical condition of
machines and devices that signal analysis of cutting forces in the frequency domain is also
often used as a signal analysis in time domain. Modern methods of measuring and processing
the measurement results significantly facilitate the analysis in the frequency domain.
Application of Fast Fourier Transform of a registered, time course of the signal allows for
spectral characteristics. Microprocessor engineering meant that practically, this
transformation can be carried out in parallel with the measurement of cutting force signal.
Classical spectral analysis is the observation of the frequency spectrum in the entire recorded
signal. The choice of these frequencies is one of the most difficult issues. Evaluation of the
tool in studies based on tracking the signal resultant force (FRR), at a particular frequency
band. Frequency (f), however, is dependent largely on the spindle speed (n) the number of
cutter cutting tools (z):
f
n* z
( Hz )
60
(6)
After an exchange tools can change both the frequency of the vibrations (the dominant in the
spectrum) and the signal level. Based on the survey measurements of the signals of resultant
force (FRR), it was observed that with increasing wear of the blade increases the share of
energy to high frequencies.
Figure 4 shows the selected courses of the spectrum signals of resultant force (FRR) in the
frequency domain. But up to this consumption value of amplitude remains comparable level.
342
As for the signal, it can be seen a clear increase in amplitude with increasing values of tool
wear (Fig. 5). In summary, the spectrum of signal resultant force (FRR) in frequency domain
can be used to assess the current state of the tool.
Fig. 4. Representative examples of FRR signal generated for VBmax: 0; 0,1; 0,15; 0.2(mm) and FFT
Fig. 5. The relation between change in result force (FRR) first harmonics and tool flank wear for four cutting test
TOOL FLANK WEAR MONITORING STRATEGY
Strategies to increase detection of abnormal wear of the blade used by various manufacturers
typically rely on increasing the selected measurement signal (changing with tool wear)
accompanying consumption. May be a measure of the average, maximum value of signal
strength, a linear combination of signals of cutting forces. Evaluation of measurement chosen
343
is usually performed after the operation. Denote M as a sharp tool of measurement
corresponds to the initial value of M0. During the wear of the blades measure increases,
resulting in his dulled (at the end of the cutter life T) value of MT (Fig. 6). Learning the system
is processing the first object with a sharp instrument. At its basis is determined the level of MT
border, on the basis provided by the operator maximum percentage increase in the value of
measuring dMT:
dM T ·
§
(7)
M T M 0 ¨1 ¸
100
%¹
©
dM T
MT M0
100%
M0
(8)
Fig.6. The increase in cutting forces accompanying of the tool wear
Used part of the shelf of the tool life is by definition a linear function of time. It estimates the
process on the basis of conduct diagnostic signal which may, but need not be a linear function
of time. Based on this simplification, the part of the shelf of the tool life can be set as:
'T
· 10 4
§ M
¨¨
1¸¸
© M 0 ¹ dM T
(9)
In conclusion, it is worth noting that the usefulness of the proposed strategy depends on the
correlation between signals of cutting forces and of the tool wear. It is of little importance in
the workpiece, the material blades or other cutting conditions. The strategy will be effective if
accompanied by of the tool wear would be substantial (preferably linear) increase in the
signals of cutting forces. But you should remember this, because there are cases where the
dependence of w forces the consumption jest too weak to be able to be used if the proposed
use and any strategy based on measurements of signals cutting force. Figure 6 shows the
results from the developed strategy. As you can see, the estimation of tool wear (¨T) has been
correctly interpreted.
Fig. 6. The used-up portion of the tool life ( T=t/T) was used as the tool condition indicator
344
CONCLUSIONS
This paper has presented the strategy for monitoring the amount of flank wear and
interrelationships between cutting force harmonic and tool wear in process milling. Certain
harmonics increase significantly with flank wear while other harmonics remain unaffected.
An on-line monitoring strategy using the cutting force harmonics magnitudes as indicator
to tool flank wear was developed and verified experimentally.
REFERENCES
[1] P. Bamdyopadhyay, E.M. Gonzalez, R. Haung, S.M. Wu, A feasibility study of on-line
drill wear monitoring by DDS methodology, Int. J. Mach. Tools Des. Res. 26 (3) (1986) 245257.
[2] L.C. Lee, K.S. Lee, C.S. Gan, On the correlation between dynamic cutting force and tool
wear, Int. J. Mach. Tools Manuf. 29 (3) (1989) 295-303.
[3] G.S. Li, W.S. Lau, Y.Z. Zhang, Process wear and breakage monitoring for a machining
center based on cutting force parameter, Int. J. Mach. Tools Manuf. 32 (6) (1992) 855-867.
[4] M.A. Elbestawi, T.A. Papazafiriou, R.X. Du, Process monitoring of tool wear in milling
using cutting force signature, Int. J. Mach. Tools Manuf. 31 (1) (1991) 55-73.
[5] A. Ezzat, R. Sayed, R.M. El-Zahry, A new prediction strategy for drill clogging and flank
wear using force and torque measurements, Meatip I Assiut, 1994.
[6] I. Dan, J. Mathew, Tool wear and monitoring techniques for turning Ð a review, Int. J.
Mach. Tools Manuf. 30 (4) (1990) 579-598.
[7] Y.S. Tarng, Study of milling cutting force pulsation applied to the detection of tool
breakage, Int. J. Mach. Tools Manuf. 30 (4) (1990) 651-660.
[8] I.N. Tansel, C. Mclaughlin, Detection of tool breakage in milling operation, the time series
analyses approach, Int. J. Mach. Tools Manuf. 33 (4) (1993) 531-544.
[9] W.A. Kline, R.E. DeVor, The effect of runout on cutting geometry and force in endmilling, Int. J.Mach. ToolsManuf. 32 (2) (1983) 123-140.
[10] V. Arshinov, G. Alekseev, Metal Cutting Theory and Cutting Tool Design. MIR
Publishers, 1967, p. 343.
[11] M.S. Chua, M. Rahman, Y.S. Wong, H.T. Loh, Determination of optimal cutting
conditions using design of experiments and optimization techniques, Int. J. Mach. Tools
Manuf. 33 (2) (1993) 297-305.
[12] G. Boothroyd, Fundamentals of Metal Machining and Machine Tools. McGrow-Hill
International 1983, p. 70.
Streszczenie: Powiązanie siá skrawania od zuĪycia narzĊdzia w procesie frezowania páyty wiórowej . Zu ycie
kraw dzi tn cej podczas frezowania to skomplikowany proces, który wymaga rzetelnej techniki w procesie
monitorowania i kontroli wydajno ci skrawania. W artykule zaprezentowano metod okre lania wp ywu zu ycia
ostrza narz dzia skrawaj cego na sygna wypadkowej si y skrawania (FRR) w dziedzinie cz stotliwo ci. Pomiary
si (na kierunku X i Y) przeprowadzono za pomoc si omierza piezoelektrycznego podczas frezowania p yty
wiórowej. Zu ycie narz dzi mierzono w sposób off-line.
Krzysztof Szwajka,
Warsaw University of Life Sciences,
02-776 Warsaw
Nowoursynowska 159 str.
Poland
An overview of data acquisition system for cutting force measuring and
optimization in milling
KRZYSZTOF SZWAJKA1), JOANNA ZIELI SKA-SZWAJKA 1)
1)
Abstract: This paper presents an approach, for the systematic design of condition monitoring system for
machine tool and machining operations. The research is based on utilising the genetic optimization method for
the on-line optimization of the cutting parameters and to design a programme for the signal processing and for
the detection of fault conditions for milling processes. Cutting parameters and the measured cutting forces are
selected in this work as an application of the proposed approach.
Keywords: milling, chipboard, cutting force, force sensor
INTRODUCTION
One of the most significant developments in the manufacturing environment is the
increasing use of tool and process monitoring systems. Many different sensor types, coupled
with signal processing technologies are now available, and many sophisticated signal and
information processing techniques have been invented and presented in research papers.
However, only a few have found their way to industrial application. The aim of this paper is
to present the cutting force measurement system for the milling. The system is based on
LabVIEW software, the data acquisition system and the measuring devices (sensors) for the
cutting force measuring. The system collects the variables of the cutting process by means of
sensors and makes transformation of those data into numerical values. Generally used
measuring devices for cutting force measuring are piezoelectric dynamometer. Delivered
signals are distorted due to their self dynamic behaviour. Their dynamic characteristics are
identified under normal machining operation. The proposed method is based on the
interrupted cutting of a specially designed workpiece that provides a strong broadband
excitation. The three components of the exciting force and the acceleration of the gravity
centre of the dynamometer cover plate are measured simultaneously. The measured values are
delivered to the computer programe through the data acquisition system. The data obtained
from the acquisition system, are a basis for the optimization of the machining process cutting parameters.
CUTTING FORCE MEASURNING
The present world market competition has attracted the manufacturer's attention on
automation of manufacturing systems for condition monitoring of machine tools and
processes for the improving of the quality of products, eliminating inspection, and
manufacturing productivity [1].
Successful condition monitoring system depends, to a vast extent, on the ability of the
system to identify any abnormalities and respond, on-line, with an appropriate action. A
condition monitoring system, as shown in Figure 1 consists of sensors, signal processing
stages, and decision making systems to interpret the sensory information and to decide on the
essential corrective action. The purpose of this paper is to presents the system for the cutting
force measuring in milling. The force generated during machining process is an important
parameter, which reflects the machining conditions. The most frequent approach taken to
milling process monitoring is to attach sensors to the machine and then monitor the signals
obtained from these sensors. With a cutting force acquisition system, the cutting process can
be monitored easily. The data acquisition system frequently commences with experiments
using a table force dynamometer which quantifies the actual force exerted on the milling tool
346
during the cutting process. Using different cutting tools and different cutting conditions, the
tool which generates the smaller force is expected to be the more effective in cutting.
Fig. 1. Monitoring system
With this system, different tools of different mechanical properties can be tried out on
the same workpiece, enabling a suitable cutting tool to be chosen. The objectives of this paper
are to design a system for the cutting forces measuring in milling. The results show that the
methodology outlined in this paper can be used to reduce the cost and complexity of the
condition monitoring system and the number of sensors required for fault identification of
milling cutters without compromising the system's ability to detect cutter faults. The
approach, however, can be used for other operations and faults with minimal modification.
SYSTEM FOR THE CUTTING FORCE MEASUREMENT
The system for the cutting force measurement presents the data acquisition system,
LabVIEW software, and the results measured cutting forces. The data acquisition system used
in this experimental model consists of dynamometer, fixture module, hardware and software
module.
A significant amount of research has been based around the measurement of cutting
forces[2- 5]. Force measurements are commonly taken using a table mounted dynamometer
during machining. These dynamometers measure the cutting force in three mutually
perpendicular directions notationally the X, Y and Z axis. The dynamometer is clamped
between the workpiece and the table or pallet. The dynamometer system is composed of a
dynamometer (Kistler 5034A3), a multichannel charge amplifier (Kister 5034A3) and their
connecting cable. When the tool is cutting the workpiece, the force will be applied to the
dynamometer through the tool. The piezoelectric quartz in the dynamometer will be strained
and an electric charge will be generated. The electric charge is then transmitted to the multichannel charge amplifier through the connecting cable. The charge is then amplified using the
multi-channel charge amplifier. In the multi-channel charge amplifier, different parameters
can be adjusted so that the required resolution can be achieved. Essentially, at the output of
the amplifier, the voltage will correspond to the force depending on the parameters set in the
charge amplifier. The interface hardware module consists of a connecting plan block,
analogue signal conditioning modules and a 16 channel A/D interface board (NI PCI-6111E).
In the A/D board, the analogue signal will be transformed into a digital signal so that the
LabVIEW software is able to read and receive the data. The voltages will then be converted
into forces in X, Y and Z directions using the LabVIEW program. The LabVIEW data
acquisition module is based on a PC computer, and is a general-purpose programming system
with an extensive library of functions and subroutines for any programming task. It also
contains an application specific library for data acquisition, serial instrument control, data
analysis, data presentation, and data storage [6].
347
SIGNAL ANALYSIS
The kind of signal analysis methods used is of some importance. Sometimes it looks
as if some researchers think that if the measured signal is acceptable then it would be possible
with a clever diagnostic tool to solve everything. Unfortunately this is not the case. The
diagnosis always needs to be based on reliable and meaningful information and this is where
signal analysis can help by providing effective features as a basis for diagnosis.
The role of signal analysis could be described as a tool which tries to pick up the meaningful
information out of the mass of information. In many cases the dilemma is that the more
sophisticated methods need a lot of raw signals and it takes time to collect this raw material
and it also takes time to perform the calculations. Consequently, many of the most
sophisticated methods are not suitable, e.g. for tool breakage monitoring. In addition, the
results with a sophisticated analysis function are influenced by the cutting process, i.e.
workpiece material, type of tool, feeding and cutting speed which makes the diagnosis more
demanding. On the other hand, very simplistic methods are fast to use and often not that
sensitive to changes in cutting conditions.
FUTURE DEVELOPMENTS
The continuing development of efficient manufacturing systems requires a greater
degree of process optimisation. Tool wear and tool breakage problems constantly disrupt
these processes. On-line tool condition monitoring strategies utilising multi-signal inputs to
monitor
and diagnose tool condition are being researched and should be encouraged.
The use of artificial intelligence, in particular neural networks, seems to be the way forward in
the handling of both a multi-signal and a multi-model strategy. The earlier research into
cutting process monitoring is still valid but now many of the methods can be combined into
one comprehensive strategy. To do so it is important that established researchers who are
familiar with the nature of the cutting process and those who operate within the area of
intelligent systems engineering come together and meet with industrial machine tool users and
manufacturers to develop a strategy for the advancement in this area. Overall there seems to
be the possibility that the next generation of monitoring tools can be engineered to fit into the
control strategies used in the design of advanced machine tools. As such, truly intelligent
monitoring systems will be capable of working with the machine to continuously optimise the
cutting process. In this area the most promising approaches would seem to be those which
will utilise, and indeed share, the signals used to control the elements of the machine tool as
the basis of process monitoring. Work in this field is continuing to provide more reliable,
robust and responsive tool condition monitoring systems which are needed in modern
manufacturing systems. They are much needed, and must be developed if truly automated
manufacturing is to develop further.
CONCLUSION
The increase in awareness regarding the need to optimise manufacturing process
efficiency has led to a great deal of research aimed at machine tool condition monitoring. This
paper also
considers the application of condition monitoring techniques to the detection of cutting tool
wear and breakage during the milling process. Established approaches to the problem are
considered and their application to the next generation of monitoring systems is discussed. A
many approaches are identified as being key to the industrial application of operational tool
monitoring systems.
Multiple sensor systems, which use a wide range of sensors with an increasing level of
intelligence, are seen as providing long-term benefits, particularly in the field of tool wear
monitoring. Such systems are being developed by a number of researchers in this area. The
348
second approach integrates the control signals used by the machine controller into a process
monitoring system which is capable of detecting tool breakage. Initial findings mainly under
laboratory conditions; indicate that these approaches can be of major benefit. It is finally
argued that a combination of these approaches will ultimately lead to robust systems which
can operate in an industrial environment.
REFERENCES
1. A. Al-Habaibeh and N. Gindy, A new approach for systematic design of condition
monitoring systems for milling processes, Journal of Materials Processing Technology, Vol
107, pp. 243-251, 2000.
2. Y. Altintas and I. Yellowley, In process detection of tool failure in milling using cutting
force models, ASME J. of Eng. for Industry, Vol. 111, pp. 149-157, 1989.
3. J.H. Tarn and M. Tomizuka, On-line monitoring of tool and cutting conditions in milling,
ASME J. of Eng. For Industry, Vol. 111, pp. 206-212, 1989.
4. J.C. Chen, A fuzzy nets tool breakage detection system for end milling operations, J. of
Adv. Manufact. Tech., Vol. 12 pp. 153-164, 1996.
5. T. Moriwaki and E. Shamoto, Intelligent tool condition monitoring for milling, CIRP 29th
Seminar on Manufacturing Systems, pp. 287–292, 1997.
6. M. Milfelner and F. Cus, Simulation of cutting forces in ball-end milling, Robotics and
Computer Integrated Manufuring, Vol. 19 (1/2), pp. 99-106, 200
Streszczenie: Powiązanie siá skrawania od zuĪycia narzĊdzia w procesie frezowania páyty wiórowej W artykule
przedstawiono podej cie, do projektowania systemu monitorowania stanu narz dzia skrawaj cego. Analiza
opiera a si na wykorzystaniu metody optymalizacji genetycznej (optymalizacji parametrów skrawania)
z zastosowaniem programu w asnego (aplikacja LabVIEW) do przetwarzania danych.
Krzysztof Szwajka,
Warsaw University of Life Sciences,
02-776 Warsaw
Nowoursynowska 159 str.
Poland
Implementing new products the chance of furniture industry development
WAC AW SZYMANOWSKI, MAGDALENA OLKOWICZ
Department of Technology, Organisation and Management in Wood Industry; Warsaw University of Life
Sciences;
Abstract: Implementing new products the chance of furniture industry development The aim of this paper is to
draw attention to the possibility of more efficient utilization the Polish furniture industry potential. Furniture
manufacturers should consider: quality, innovation and customer-oriented product, already at the level of product
design. The process of new product development (NPD process) can be supported with appropriate tools and
techniques, which task is to focus of attention the design team to create a product consistent with customers’
expectations and achievement the success on the market.
Keywords: New product development (NPD), tools and techniques, furniture industry, new product;
INTRODUCTION
The specificity of industrial activities in a significant degree is determined by its
innovative potential and development perspectives. The wood industry is a particular area, as
based on natural, ecological and renewable raw material which is wood.
Emphasised from the wood industry sector – the furniture industry dominates among
the other branch of that sector in terms of businesses numbers, employment and production
value (Ratajczak 2009). In addition, the furniture market is open to international competition,
which favors increasing the turnover by the manufacturers, but also requires from them to
become more involved in the maintenance (or improvement) achieved market position. Two
basic strategies dominate which with this end in view are chosen by domestic manufacturers:
a cost-cutting strategy and a strategy for improving advanced manufacturing technologies that
will enable them to achieve more differcieted products as the base of higher position on the
market of the furniture higher class (Mamica 2004). In European terms the cost reduction
strategy does not bring long-term effects because China – a leading furniture exporter
developing rapidly since the mid-1990s and in 2004 China outclassed Italy from the leader
position in the rating on the biggest world's exporter of furniture (the position is maintained
until today) - is unbeatable in terms of winning cheap labor over and obtainment the low
production costs. With this in mind, the Polish furniture producers should bet on quality and
innovation, as the main factors of development and take advantage of favorable Poland
location in Europe and lower production costs in Poland than in Western European countries
(Han 2009, Mamica 2004).
Matejuk (2003) points to another development factor - Polish furniture producers in
order to become competitive on the European market must search a specialization not at the
level of the industry branch but at the level of individual products. Therefore, it is very
important that manufacturers of furniture, take account of all three factors: quality, innovation
and customer-oriented product, already at the level of product design.
COMPETITION DIRECTIONS IN THE FURNITURE INDUSTRY
The world trade of furniture has increased rapidly during the past two decades. On this
fact has contributed new solutions and opportunities in the field of packaging, transport and
assemble of furniture, opening up new markets as well as reducing of trade barriers. As a
result, the world trade of furniture has increased from US$42 billion in 1997 to US$97 billion
in 2007 (Han 2009).
350
The main furniture exporters are China today. Despite the fact that since 1996 their
market share has been steadily increasing, this does not mean, however, that furniture’s giant
do not need to take any action in order to maintain or improve sales performance. In terms of
quality and unit price, China is still falls behind traditionally strong competitors such as Italy
and Germany. The counterweight to the cheaper Asian labor slowly become: well-known
brand, quality, recognizable patterns, and ‘specialization’ in the given type of product. It is
also experiencing a growing challenge from countries such as Poland and Vietnam. Xiao Han
(2009) straight points out that emerging countries (Poland and Vietnam) are expanding their
export market rapidly as well. China doesn’t still have their own brand and updated
technology, on the contrary to Poland. Moreover, Poland advantage is its location in Europe,
which provides access to the West European market. Almost 90% of our production has been
exported, 78% of which has been transported to EU countries (in 2002; Han 2009). Poland
has become an export-oriented furniture producer.
PROCESS OF NEW PRODUCT DEVELOPMENT IN FURNITURE INDUSTRY
One criterion for innovation is the ability of firms to introduce new product designs or
their significant modification (Mamica 2004). Unfortunately, unfair competition, and a
negligible chance of protecting their property rights for utility models often leads to the fact
that furniture producers reduce spending money on: research and development, product
design and implementation process of the product on the market. Taking that decision
inhibits, ipso facto, business development and customer expectations in relation to
manufactured goods are imported into the background the company policy. The manufacturer
no longer reaches the needs of buyers out.
Especially in micro enterprises (study group of 46 furniture manufacturers; Mamica
2004) the dominant model for the gaining of the design of new products is a reproduction of
the available designs or use your own creativity, which usually is not based on professional
grounds. Using the services of designers in the furniture factories in the micro sector, is a rare
phenomenon. Studies conducted in 2009 among the 55 Polish furniture producers (Fabisiak
2009), however, show that in 2005-2008, 68% of surveyed companies admitted that it has
made investments in the field of new product development or modernization (modification) of
previous designs. Manufacturers also declared that the most important factors determining
their decision on the development of products are: customer expectations, the desire to
achieve competitive advantage and strengthening brand in the market.
Referring to the studies conducted on the Spanish market (March-Chorda 2002), it can
be noted that the furniture industry has the potential to exploit the new product development
process to enhance competitive advantage in the market.
The possibility of relatively rapid introduction of new furniture on the market is
connected with appropriately carried out the product design process (from idea generation
through: customer’s expectations researches, designing and engineering project, up to a
prototype). Other determinants of the product implementation in the furniture industry are
presented in table 1 (tab. 1).
Table 1. Conditionings for carrying out the development of new products in the furniture industry
Environment of process
of the new products development
Technical uncertainty
Attitude of the market
Potential of innovations introduction
Furniture industry
Traditional character of the sector and its products; standardized
raw materials and production processes; technological dependency
on the suppliers and raw materials;
The conservative attitude of the market is connected with a
discouragement factor in the promotion of novelties;
Stable, traditional sector with a low potential for product
351
Failure rate of product innovation
Process development of new products
Period of useful product life before
undergoing modification
Time of NPD process
innovation, not going further than simple design modifications; the
high rate of segmentation in this sector makes it difficult to
penetrate new segments through the development of new products;
The sector immune to failure problems in innovation because of a
low degree of changes introducing into new products;
The sector belongs to industries which require less time for NPD,
for the most part due to the continuity of their product range. The
rapid development of new products requires only the participation
of design activities;
Products remain unchanged probably for longer than they should;
About 2-6 months; relatively short period of NPD with reference to
the global average cycle time (about 1 year);
Source: Own study (based on March-Chorda 2002);
SELECTION OF NPD TOOLS AND TECHNIQUES
Utilization of appropriate tools and techniques in the NPD process can assist firms to
achieve better performances in launching new products on the market. However, in practice,
many useful tools and techniques are not utilized effectively (Yeh 2008) or in general they are
ignored - manufacturers act intuitively.
Table 2. NPD tools and techniques
No
1
NPD tools and techniques
Quality functional development
(QFD)
2
Project management
3
Design of experiment (DOE)
4
Concurrent engineering (CE)
5
Failure model and effect analysis
/ Design failure model and effect
analysis (FMEA/DFMEA)
6
Collaborative design
7
Taguchi method
8
Design for six sigma (DFSS); Six
sigma program
9
10
11
12
Benchmarking
Design for assembly (DFA);
Design for manufacturing
(DFM)
Product data management
(PDM)
Group technology (GT)
Description of tool / technique
Taking into account at all stages of designing the largest possible
number of factors which may affect product quality or
manufacturing processes. Also, "translation" customer expectations
in relation to the product into technical language.
Realization of established aims by means of concrete activities and
in appointed time.
Utilization of experimental methods to determine and optimize
factors affecting the quality of the process and product.
Different stages: design, implementation and testing of the
prototype, marking the amendments and correction, and then
designing and making the instrumentation, are - if possible - making
in parallel. The information are passing on a continuous basis.
Identification of potential defects and the reasons causing it. It
consists in estimating the risk of emergence the defects in the
product or process, describing the causes and their significance, and
propose solutions on the basis of preventive or corrective measures.
The common use of design techniques and product development to
improve products launching on the market in order to they will be
successful.
The product designing should be carried out in three stages: system
design, design of system parameters and tolerance design .
Improving the quality makes sense only if benefit by customers and
organizations. The aim of DFSS is to improve financial
performance through quality improvement (tools and methods of
quality management).
Analysis and implementation of solutions used by competitors.
DFA – designing products easy to assembly,
DFM – designing products easy to production,
Enable the collection and sharing of data about the structure of the
product, its documentation and its manufacturing processes,
including the possibility of processing in the database.
Establishing a standard process technology for a set of
technologically similar products.
352
Improving the design work, while - through the work of the network
- the parallel tracking of course all the work involved. Any
discrepancies can be quickly eliminated.
14
The method enables manufacturers to know more customer demand,
to measure their preferences and to examine similarities and
differences between alternative options to choose from a wide range
of products.
15 Fishbone analysis
The presentation in graphical form a set of factors affecting the final
outcome of the process.
16 Value analysis / Value
Analysis of the project in order to eliminate waste before and after
engineering (VA/VE)
the commencement of production.
17 Theory of inventive problemThe method of complex solving problems that is how to integrate
solving (TRIZ)
the two contradictory demands in one system?
18 Knowledge management (KM)
Attempt to make the best use of knowledge that is available in the
organization, creating new knowledge and increasing its
understanding.
Source: Own study (based on: Yeh 2008, Hamrol 2008)
13
Computer-aided systems (CAD):
manufacturing (CAM),
engineering (CAE)
Conjoint analysis
In the Polish companies from the furniture industry highlights, so far, only one tool for
supporting the design of new products: CAD software. They use also some systems for
collecting data e.g. CRM (Customer Relationship Management) (Fabisiak 2009). Meanwhile,
there are several dozen of methods and tools used successfully all over the world in various
industries. Survey and brief description of the most important are presented in table no 2 (tab.
2).
SUMMARY
The furniture is the industry which potential has not yet been fully exploited. Furniture
manufacturers in order to become competitive on the European market must look a
specialization not at the level of the sector, but at the level of individual products. For this
purpose, some methods and tools for designing products (tab. 2) should be implemented in the
furniture factories.
However, there is lack of researches that would answer to the questions: how exactly
is the NPD process acting now in the furniture factories? which the NPD tools and techniques
are they using now? and launching which of them would be good? and most importantly how the NPD process must occur in order to be effective and bring the expected profit?
Ratajczak (ed., 2010) among mentioned the desired trends in the Polish researches from scope
of wood science also points to: "analyze the effectiveness of the implementation of new
technologies and products (…)”.
In connection with the gap in the current area of research, and noticing the importance
of issues taken on in this publication, the subject will be continued.
REFERENCES
1. FABISIAK B., DZI GIELEWSKI S., 2009: Processes of development and
implementation of new products in selected furniture manufacturing enterprises; Ann.
WULS-SGGW, For and Wood Technol., 68; s. 237- 242;
2. HAMROL A., 2008: Zarz dzanie jako ci z przyk adami; Wyd. Naukowe PWN,
Warszawa,
3. HAN X., WEN Y., KANT S., 2009: The global competitiveness of Chinese wooden
furniture industry; Forest Policy and Economics 11; Elsevier B.V., s. 561- 569;
4. MAMICA
., 2004: Przemys meblarski Kalwarii Zebrzydowskiej – klaster
przemys owy?; Zeszyty Naukowe Akademii Ekonomicznej w Krakowie nr 667; Kraków,
s. 137-150;
353
5. MARCH-CHORDA I., GUNASEKARAN A., LLORIA-ARAMBURO B., 2002: Product
development process in Spanish SMEs: an empirical research; Technovation 22, Elsevier
Science Ltd., s. 301-312;
6. MATEJUK J., 2003: Budowa konkurencyjno ci przedsi biorstw w okresie transformacji;
Wyd. PRET S.A., Warszawa, s. 220;
7. RATAJCZAK E. (red.); 2009: Innowacyjno sektora drzewnego w Polsce; ITD, Pozna ,
8. RATAJCZAK E. (red.); 2010: Post p naukowy w drzewnictwie; ITD., Pozna , s. 48;
9. YEH T.-S., PAI F.-Y., YANG C.-C., 2010: Performance improvement in new product
development with effective tools and techniques adoption for high-tech industries; Qual
Quant 44, Springer Science + Business Media B.V.; s. 131-152;
Streszczenie: WdraĪanie nowych produktów szansą na rozwój meblarstwa Celem niniejszej
publikacji jest zwrócenie uwagi na mo liwo efektywniejszego wykorzystania potencja u
polskiego meblarstwa. Producenci mebli powinni uwzgl dnia : jako , innowacje oraz
zorientowany na klienta produkt, ju na poziomie projektowania wyrobu. Sam proces rozwoju
nowego produktu mo e zosta wsparty poprzez stosowanie odpowiednich narz dzi i technik,
które maj za zadanie ukierunkowa zespó projektowy do wykreowania produktu zgodnego z
oczekiwaniami klienta oraz do odniesienia sukcesu na rynku.
Wac aw Szymanowski, Magdalena Olkowicz
Warsaw University of Life Sciences;
Department of Technology, Organisation and Management in Wood Industry;
ul. Nowoursynowska 159, 02-776 Warszawa; Poland
(Ann. WULS- SGGW, For and Wood Technol. 72, 2010)
Influence of the speed machining to the tool life during processing of the
particleboard
KAROL SZYMANOWSKI , JAROS AW GÓRSKI
Abstract: Influence of the speed machining to the tool life during processing of the particleboard. In the article
relationship between cutting speed and tool life during machining particleboard was estimated. The mentioned
researches were conducted with usage of three rotation speeds of the spindle. In the experiment milling cutter
with one blade was used. The diameter of cutter was 40 mm. During experiment grooves were milled to the
depth of 6 mm with the constants feed to the blade 0.15 mm. For determining the degree of exhausting the tool
VBmax indicator was used (maximum width of wear on clearance face of cutting edge). According to received
results was established, that during the milling of the particleboard, the speed of machining has the significant
effect to the life of the cutting tool.
Keywords: tool, milling, tool life, cutting speed
INTRODUCTION
Machining wood materials including particleboard is a process often performed in
many branches of industry. The process of the machining should be conducted in such way, to
possibly lower costs and get the required quality. Therefore, the long topicality of the cutting
tool is a desirable feature. In many articles concerning the milling of particleboard a link
between the speed of machining and the tool life of the cutting tool was observed [Stefaniak
1970, Porankiewicz 1993]. However many aspects from this scope still aren't clear, therefore
this issue should still carefully be examined.
Examinations were conducted on the CNC milling centre BUSELLATO JET 130. As
a tool was used milling cutter with one blade (FABA). The diameter of cutter was 40 mm
[Fig. 1]. The angle of the blade of the knife was 76 degrees; knives were made from the
carbide. As a material for machining was used particleboard. During experiment grooves were
milled to the depth of 6 mm and the length of 450 mm [fig. 2]. For determining the degree of
wearing of the edge VBmax indicator was used (maximum width of wear on clearance face of
cutting edge). VBmax was being read out on the workshop microscope. The criterion of
blunting the blade was adopted on the level of 0.5 mm. The research was made for the three
rotation speeds of the spindle n1 = 18000; n2 = 15000; n3 = 12000 rpm what at the given
diameter of the tool correlating to cutting speed of v1 = 37.68; v2 = 31.40; v3 = 25.12 m/s.
(table 1).
Tab.1 Milling parameters
355
Fig.1 Milling cutter
Fig. 2 Schema of the milling process
RESULTS
On fig. 3 the results of experiment were shown. For the v1 speed the blade covered with the
criterion of blunting (VBmax > 0.5 mm) is fulfilling after milling 4.95 m. For the v2 speed,
VBmax = 0.51 was get after machining grove for lengths 6.3 m. At the speed of v3 machining
this length is 9.9 m. Results are demonstrating, that together with the increase in the speed of
machining, pace of wearing out tools clearly grow.
Fig.3 Course of wearing tools out in the function the way for different speeds of machining.
356
Fig. 4 Course of wearing tools out in the function of
the time for of different speeds of machining
Fig. 5 Influence of the speed machining to the tool life
For above data analytically fixed rates of the F.W.Taylor pattern were calculated.
k= -2,56 oraz Cv = 49,25
Fig. 6 Dependence of the tool life to the cutting speed.
On the fig. 6 a logarithmic graph of the influence of the cutting speed to the tool life is shown.
For above data the rate of the determination amount is R= 957.
CONCLUSION
Results of above examinations allow for expressing the following conclusions:
1. Speed of machining the particleboard with the tool from carbides has explicit influence on
the tool life of the cutting tool.
2. The increase in the speed of machining is reducing the tool life of the cutting tool.
REFERENCES
1. JEMIELNIAK K.,1998: Obróbka skrawaniem” Oficyna Wydawnicza Politechniki
Warszawskiej”
2. PORANKIEWICZ B.,1985: Wybrane problemy z narz dzi skrawaj cych do obróbki
drewna. Wydawnictwo Akademii Rolniczej w Poznaniu
3. PORANKIEWICZ B., 2003: T pienie si ostrzy i jako przedmiotu obrabianego
w skrawaniu p yt wiórowych. Roczniki Akademii Rolniczej w Poznaniu, Rozprawy
Naukowe, zeszyt 341, Pozna .
357
4. STEFANIAK W.,1970: Wp yw szybko ci skrawania na t pienie si ostrzy pi
tarczowych z nak adkami z w glików spiekanych przy pi owaniu p yt wiórowych. Folia
For. Pol. B,9:66-77
Streszczenie: Wpáyw prĊdkoĞci skrawania na trwaáoĞü narzĊdzia podczas obróbki páyty
wiórowej. W artykule okre lono wp yw pr dko ci skrawania, na tempo zu ywania si
narz dzia podczas skrawania p yty wiórowej trójwarstwowej. Badania przeprowadzono z
zastosowaniem trzech pr dko ci obrotowych wrzeciona. Do bada u yto g owicy frezarskiej
jednoostrzowej o rednicy 40mm. Frezowano rowki o g boko ci 6mm ze sta ym posuwem
na ostrze 0,15mm. Do okre lenia stopnia zu ycia narz dzia pos u ono si wska nikiem
Vbmax (maksymalne starcie na powierzchni przy o enia). Na podstawie otrzymanych
wyników stwierdzono, e podczas frezowania p yty wiórowej, pr dko skrawania ma
znacz cy wp yw na trwa o narz dzia tn cego.
Sáowa kluczowe: narz dzie, ,skrawanie, trwa o , pr dko
Karol Szymanowski
Wood Mechanical Processing Department,
02-776 Warsaw,
Poland
skrawania
Impact of feed speed on the processing quality of seats on a multi-spindle
drilling machine
WALDEMAR SZYMA SKI, GRZEGORZ PINKOWSKI, ANDRZEJ KRAUSS
Abstract: Impact of feed speed on the processing quality of seats on a multi-spindle drilling machine. The study
presents results of investigations on the effect of the feed speed on the state of seat edges and their dimensionalshape accuracy made on a multi-spindle drilling machine. In the course of the performed experiments, ten
variants of feed spped comprising the entire range of the drilling machine settings were applied. The seats, 5 and
30 mm deep, were made in two wood species (beech and pine) in longitudinal and transverse directions to wood
grain using two kinds of drilling bits of differing structure of the working part. The experiments showed that the
employed feed speed affected the quality of seat execution and helped establishing favourable ranges of speeds
from the point of view of the processed material, direction of drilling and the effectiveness of processes carried
out on a multi-spindle drilling machine.
Keywords: multi-spindle drilling machine, feed speed, wood drilling, seat edge condition.
INTRODUCTION
The observed constructional development of woodworking machines makes it possible
to obtain high efficiencies in fields of processing of wood and wood-derived materials. High
efficiency, in turn, should ensure appropriate quality and accuracy of processed edges and
surfaces which is associated with the choice of appropriate processing parameters. Wrong
selection of machining parameters can result in processing defects and increase wear of
cutting edges.
Basic kinds of processing are characterised by properly selected feed sppeds adjusted
to machining conditions. In the case of drilling processing carried out with the assistance of a
traditional multi-spindle drilling machine, the feed speed parameter is most frequently omitted
and its value is set as a constant parameter, frequently – maximal. This is the result of the
adopted assumption that, for this kind of processing, there is no need for feed speed selection
and that this approach is one of the ways to increase output. The issue of increased efficiency
is important bearing in mind the fact that in the drilling cycle conducted on a multi-spindle
drilling machine, we can distinguish such stages as: approach of the bit to the processed
material, proper drilling and return where the distance of the approach and return is frequently
distinctly longer than the drilling depth.
In literature on the subject, studies associated with optimal choice of the feed speed in
drilling operations are rare, especially those regarding drilling of solid wood with the
assistance of a traditional multi-spindle drilling machine. The few available publications deal,
in a general way, with the quality of seats made in wood-based materials (Taylor & Lemaster
2006; Davim et al. 2007). Catalogues of companies dealing in tools (Leitz-Lexicon 2009)
specify feed sppeds in woodworking machines with possibilities of stepless regulation of
spindle rotational spped. In the case of a multi-spindle drilling machine, this speed is constant.
The objective of the performed investigations was to analyse the influence of the feed
speed on the results of the drilling process and, in this way, elaborate general
recommendations regarding appropriate realisation of these processes. The impact of the feed
speed on a number of factors was checked. In this study, the main focus was on the
relationship between the feed speed and the quality of seat edges in processing of solid wood.
In an earlier publication (Kowaluk et al. 2008), the authors presented the effect of the feed
359
speed on selected results of drilling of laminated chip boards and concluded that there was a
clear relationship between the condition of seat edges made in chip boards covered with
different kinds of laminates and the applied feed speed.
Experiments were performed on a single-side, multi-spindle drilling machine with a
working assembly consisting of 19 spindles arranged in one plane. The rotational speed of
spindles amounted to n = 2800 min-1. The feed motion of spindles was achieved using a
double-sided, pneumatic servo with a working distance of 70 mm.
The drilling depth was set with the aid of a screw mechanism which controlled the
operations of a separating valve which delivered air to the servo of the feed motion. The set
depth of drilled seats was: 5 and 30 mm.
The feed speed (vf) of the drill working assembly was regulated using a specially
calibrated throttle valve. The following ten feed speeds were applied in experiments: 0.18;
0.27; 0.40; 0.60; 0.75; 0.92; 1.35; 1.99; 2.47 and 3.09 m · min-1, which were determined as
mean values on the basis of numerous experiments.
Two types of uniform screw drill bits of 8 mm diameter, with the working part
equipped in a cantering point and spurs and additional calibrating edges were used. Drill bits
designated as W1 had cutters situated at the main cutting edge as well as a threaded shank and
a centring point, while drill bits designated as W2 had cutters situated at the height of the
additional calibrating edge and a cylinder shank with a bevel and a stop screw. The
experimental drills were selected bearing in mind repeatability of linear and angle parameters
of working parts.
Two solid and dry wood species: beech and pine were selected for investigations and
special samples with appropriately oriented grain were prepared.
Measurements and evaluation of the condition of the examined seat edges were carried
out with the assistance of micrometric measuring equipment and microscopic methods using
images registered with the aid of digital technique. The seat edge condition was represented
by the number and form of fibre damages as well as the dimensional-shape accuracy analysis
of the top part of seats.
Table 1 shows images of the condition of seat edges made in pine wood in directions
longitudinal and transverse to grain using the adopted feed speeds. The images refer to seats 5
mm and 30 mm deep made using two kinds of drill bits: W1 and W2. In the case of the
longitudinal drilling direction for the applied feed speeds ranging from 0.18 – 0.92 m · min-1
seat edges did not show any damages and their quality was good. For feed speeds vf = 1.35
and 1.99 m · min-1 satisfactory dimensional-shape quality and accuracy of seats was achieved
despite small fibre damages covering 10-15% of the seat edge length. When feed speeds of
vf = 2.47 and 3.09 m · min-1 were applied, edges of the obtained seats were deformed with
numerous damages and torn grain. The obtained irregular seat shapes limit technological
usefulness of obtained seats.
360
Table 1. View of the condition of seat edges made in pine wood using the adopted feed speeds.
*)
Feed speed ranges for the repeated condition of seat edges.
W1/W2 representative picture of seats made using W1 and W2 drill bits
**)
When seats in pine wood were drilled in transverse direction, the condition of seat
edges was good for feed speeds ranging from 0.18 – 0.75 m · min-1. Higher speeds caused
increasingly greater damages of edges in the form of numerous torn fibres. Speeds
vf = 1.99 m · min-1 and higher yielded seats of unacceptable technological usefulness with
numerous, deep grain raptures and edge damages.
The edge condition and dimensional-shape accuracy of the top part of seats made
using W1 and W2 drill bits within the range of experimental feed speeds, both for the
longitudinal and transverse directions of drilling, were similar.
The applied drilling depths of 5 mm and 30 mm did not affect significantly the
condition of the obtained seats with the exception of the transverse direction of the feed speed
0.92 – 3.09 m · min-1 where a worse seat edge condition for 5 mm deep seats can be noticed.
The edge condition of seats drilled in beech wood is presented in Table 2. The quality
of seat edges for the analysed feed speeds 0.18 – 0.92 m · min-1 was described as good both
for longitudinal and transverse directions of drilling in relation to wood fibres. For the feed
speeds vf = 1.35 and 1.99 m · min-1, the state of seat edges was considered as good despite the
occurrence of slight defects, primarily when drilling in the transverse direction. The vf = 2.47
and 3.09 m · min-1 speeds for transverse direction resulted in serious damages of seat edges
where numerous fibres were torn out and small deposits could be seen along edges causing
seat deformation. In the case of the longitudinal direction, for the applied feed speeds of 2.47
and 3.09 m · min-1, acceptable quality of seat edges was observed with only small damages
and deposits. Relatively worse effects were obtained for seats 5 mm deep at vf = 3.09 m·min-1.
361
Table 2. View of the condition of seat edges made in beech wood using the adopted feed speeds
*)
Feed speed ranges for the repeated condition of seat edges.
W1/W2 representative picture of seats made using W1 and W2 drill bits
**)
An attempt was made for seats made in beech wood to measure the height of the
occurred deposits and the depth of damages of seat edges employing the profilometer method.
The problem will be discussed in a more comprehensive manner in a separate publication.
The obtained measurement and selected results are presented in Figure 1.
vf = 2,47 m · min-1
Material
vf = 3,09 m · min-1
Damages
maximum height maximum depth maximum height
[Pm]
[Pm]
[Pm]
maximum depth
[Pm]
Beech wood
320
420
> 480
> 480
transverse direction
Beech wood
20
50
longitudinal direction
Fig. 1. Measurements of heights and depth of damages of seat edges in beech wood and example results
362
In the case of all beech wood combinations, no significant differences were observed
regarding the quality of seats made using W1 and W2 drill bits.
The 5 mm and 30 mm depth of seats in beech wood did not affect in a significant way
the state of their edges; only in the case of the transverse direction for feed speeds ranging
from 1.35 – 3.09 m · min-1, worse condition of edges could be observed for seats of 5 mm
depth. For 0.18 and 0.27 m · min-1 feed speeds in the case of seats 30 mm deep made mainly
using W2 bits, burns of inner seat surfaces were noticed.
CONCLUSIONS
Table 3 presents the examined ranges of feed speeds from the point of view of the
quality of seats drilled in beech and pine wood with the assistance of a multi-spindle drilling
machine determined on the basis of the performed investigations.
Table 3. Investigated feed speed ranges of multi-spindle drilling machine in aspect the quality of seats
Material
vf [m · min-1]
0,18 0,27 0,40 0,60 0,75 0,92 1,35 1,99 2,47 3,09
Beech wood
Beech wood
Pine wood
Pine wood
x – favourable vf ranges
w – conditional, favourable vf ranges
w
x
x
x
x
w
w
x
x
x
x
x
w
x
x
x
w
w
x
x
x
x
x
w
w
Values vf = 0.18 and 0.27 m · min-1 presented in Table 3 guarantee the appropriate
quality of the drilled seats but they are not recommended due to overheated tools during the
operation and occurring burns inside seats. The vf = 0.40 m · min-1 speed was considered as a
limiting value with regard to the efficiency of the drilling process.
The observed better quality of seats made in the longitudinal direction and worse of
those made in transverse direction using drill bits with centring points and cutters was
somewhat surprising.
On the basis of the performed investigations, the range of feed speeds 0.60 –
1.35 m · min-1 should be considered as recommendable to obtain good quality seats in solid
wood using multi-spindle drilling machines.
REFERENCES
1. DAVIM J. P., CLEMENTE V. C., SILVA S., 2007: Drilling investigations of MDF
(medium density fibreboard). J Mater Process Technol (in press)
2. KOWALUK G., SZYMA SKI W., BEER P., 2008: Preliminary identification of the
feed speed influence on chosen effects of laminated particleboard drilling. Drewno –
Wood 2008, vol. 51, nr 180: 55 – 62
3. TAYLOR J. B., LEMASTER R. L., 2006: Drilling of Wood and Wood Composites:
Hole Quality. Surface Breakout and Flute Clogging. Proc. Of FPS 600 International
Convention, 25-28.06.2006. Newport Beach Marriott, Newport Beach, California,
USA
4. LEITZ-LEXICON, 2009. Edition 5
363
Streszczenie. Wpáyw prĊdkoĞci posuwu na jakoĞü gniazd na wiertarce wielowrzecionowej. W
pracy przedstawiono badania wp ywu pr dko ci posuwu na stan kraw dzi i dok adno
wymiarowo kszta tow gniazd wykonywanych na wiertarce wielowrzecionowej. W realizacji
bada zastosowano dziesi
wariantów pr dko ci posuwu obejmuj cych ca y zakres
mo liwo ci nastaw wiertarki. Gniazda o g boko ciach 5 i 30 mm wykonywano w dwóch
gatunkach drewna (buk i sosna) w kierunku wzd u nym i poprzecznym do w ókien, za
pomoc dwóch rodzajów wierte o zró nicowanej budowie cz ci roboczej. Stwierdzono
wp yw pr dko ci posuwu na jako wykonywanych gniazd oraz ustalono korzystne zakresy
pr dko ci w uj ciu obrabianego materia u, kierunku wiercenia i wydajno ci procesów
realizowanych na wiertarce wielowrzecionowej.
Waldemar Szyma ski, Grzegorz Pinkowski, Andrzej Krauss
Department of Woodworking Machinery and Fundamentals of Machine Construction,
e-mail: WSzyma [email protected]; [email protected]; [email protected]
Economic benefits of bio-energy generation from wood waste
MAREK TABERT, WOJCIECH LIS
Department of Economics and Wood Industry Management, Poznan University of Life Sciences
Abstract: Economic benefits of bio-energy generation from wood waste. The article describes the production
technology of wood pellets based on a production line of medium capacity and presents basic parameters of
wood pellets depending on the type of the used raw material. Economic and ecological benefits of bio-energy
production using wood waste are presented. It was shown that wood pellets, as a fuel, are characterized by a low
production cost per 1 kWh energy (bio-energy) in comparison to other commonly used fuels.
Keywords: bio-energy, renewable energy sources, pellets, wood waste, effective costs of generation
INTRODUCTION
In the course of combustion of fossil fuels waste products, particularly gases, are
formed in large amounts. When released to the atmosphere they have a negative effect on the
natural environment. Concern is voiced in the scientific community comprising
conservationists first of all in connection with CO2 emission, occurring as a result of
combustion of hard coal, brown coal or oil. It disturbs the balance of this gas in the Earth
atmosphere. This may be a significant factor having a negative impact on climatic conditions
on Earth, which changes have been recorded for at least a decade.
In order to reduce the threat resulting from CO2 emission it is recommended to replace
fossil fuels with renewable energy sources. In accordance with the legal regulations of the
European Union sellers of energy are obliged to purchase energy coming from renewable
energy sources. In Poland by the end of 2010 the proportion of energy coming from
renewable energy sources in the total energy consumption should exceed 7.5%. In the next
years this proportion is to increase regularly so that it reaches at least 15% in the year 2020.
According to the data of the Energy Regulatory Office of June 2010, a total of 1 229
installations using renewable energy sources were operating in Poland, at a power of 2 282
GW, including 15 power plants using biomass and generating 252 MW (www.ure.gov.pl).
Bio-fuels produced from natural organic raw materials (biomass) constitute important
renewable energy sources. Due to their origin, energy obtained from biomass is called bioenergy. Among numerous types of biomass considerable interest is focused on wood,
particularly wood waste, from which wood pellets are produced. The German and Austrian
standards define pellets as granulated (pelleted) material produced from pure sawdust coming
from hardwood species. In contrast, in Poland this term is usually applied to pelleted wood
material produced from any wood species, or it may even refer to pelleted product produced
from any organic raw material. Due to the economic and ecological advantages of wood
pellets the demand for this type of bio-fuel has been increasing both on the national and
international scale. Production of wood pellets has been developing so intensively that
shortages of raw material, particularly of the highest quality, have been observed.
TECHNOLOGY OF WOOD PELLET PRODUCTION
Wood pellets are produced from sawdust and chips coming from rough mills where it
is a waste product, or from chips specially produced from leftovers. The raw material is
pressed under high pressure with no additional binding agents used. As a result of this process
365
the material takes the form of cylinders with a diameter from 6 to 25 mm. The size of the
diameter for pellets is specified by the European standard.
The technological process of wood pellet production occurs in five stages. It is
realized in production lines composed of several machines. Figure 1 presents a diagram of a
medium-sized wood pellet production line. The first stage of the process is drying of the raw
material. Wood waste in the form of sawdust, particles or chips, constituting the basic
production material, may be characterized by moisture content of over 20%, which
considerably exceeds the level required for the technological process. Thus additional drying
of the material is required. This process is run until the raw material has a moisture content
ranging from 10% to 14%. Drying is performed in belt driers or rotary driers, which are
heated with a mixture of combustion gas, air and steam.
Fig. 1. A diagram of a medium-sized wood pellet production line - producer: Amandus Kahl (Germany)
Source: based on www.akahl.de, modified by the author.
The next stage of the technological process comprises disintegration of the wood
material. This process is run until grains of max. 4 mm in diameter are obtained. This
procedure is applied in order to produce a semi-product being uniform in size. Milling is
performed in beating mills. In the next stage of the process such prepared material is pressed
and pelleted (Fig. 2).
Fig.2. A fragment of the press for pressing and pelleting of wood material
Source: based on www.akahl.de, modified by the author.
For this purpose a press with a ring die is used. Depending on the diameter intended
for the final product, a die with openings of 6 mm or 8 mm is used. Disintegrated wood
material is next pressed through die openings using pressing cylinders (rollers) mounted on
the head over the die. Material pressed to form these cylinders is pushed from the die.
Cylinders are divided using a cutting knife into sections of several centimeters in length,
typically 2 - 4 cm. Thus produced wood pellets are cooled in counter-current coolers. As a
result of this procedure shape and strength parameters of the final product are stabilized. In
the last but one stage too small wood pellet fractions are sieved off on fraction sieves. In the
366
end the final wood pellet product is packaged into bags of 10, 15 and 20 kg, or 1000 kg (the
so-called Big Bag). For bulk buyers it may also be supplied in tanks. The basic properties of
wood pellets depending on the wood species are presented in Table 1.
Table 1. Basic parameters of wood pellets depending on wood species
Type of fuel
Pellets from pine sawdust
Pellets from beech sawdust
Pellets from oak sawdust
Pellets from willow
Bulk
density
[kg/mp]
667,6
598,4
608,7
592,3
Moisture
content
[%]
9,61
7,04
7,95
8,78
Ash
content
[%]
1,29
0,80
0,40
2,15
Calorific value
[MJ/kg]
17,67
17,81
18,03
17,09
Source: a study by the author based on Stolarski et al. 2007.
BENEFITS OF ENERGY GENERATION FROM WOOD PELLETS
Wood pellets are an attractive fuel both from the economical and ecological point of
view. They are characterized by a relatively good calorific value (see Table 1) in comparison
with other bio-fuels and have a heating value exceeding 70% calorific value of the best coal
grades. Their purchase price is competitive (650 – 750 z /t), which results in low heating
costs. Moreover, it is easy to use in heating boilers (Kry owicz et al. 2004).
A comparison of effective costs (i.e. taking into consideration boiler efficiency) of the
generation of 1 kWh energy obtained from combustion of wood pellets (0.17 z /kWh) shows
that it is similar to the cost of production of energy from carbon in the form of pea coal (0.16
z /kWh). Higher costs of energy production are incurred in case of coke (0.30 z /kWh), fuel
oil (0.27 z /kWh), liquefied petroleum gas – propane (0.22 z /kWh) and natural gas (0.21
z /kWh) (Tabert, Lis 2009).
Combustion of wood pellets does not introduce new pollutants to the natural
environment. Carbon dioxide, released when burning wood in the form of pellets, enters the
natural cycle of this gas in nature, as a result of its absorption by green plants, particularly
forests. Forests are ecological systems, which are regenerated naturally and continuously as a
result of absorption of solar energy. In photosynthetic processes green plants transform CO2
captured from the atmosphere into organic substances, first of all cellulose (C6H10O5)n. It is
the primary component of wood, which is next a raw material for the production of pellets. As
a result the amount of carbon dioxide in the natural environment remains unchanged,
circulating in the natural cycle. For this reason wood pellets are considered to be a valuable
source of bio-energy (Tabert, Lis 2009).
Ecological advantages of wood pellets include also the emission of only trace amounts
of SO2 during combustion and the production of slight amounts of ash, containing no
pollutants harmful for the environment. Ash contains non-organic compounds, mainly
potassium and calcium carbohydrates. These compounds are good quality mineral fertilizer,
which may be used in agriculture in crop nutrition (http://www.pellets.pl). The pelleted form
facilitates automatic feeding to heating boilers. Modern boilers fueled by wood pellets
practically require no manual operation. Ash is removed up to several times a month. In this
respect maintenance of pellet-fueled boilers is similar to the operation of oil or gas-fueled
boilers. However, it is almost two times cheaper.
An advantageous property of wood pellets is connected with its capacity to be safely
stored, since this fuel exhibits no tendency to spontaneous ignition. In turn, it has a higher
flash-point than coal, which facilitates the combustion process. It takes up thirty times less
space than the raw material from which it was produced, which considerably reduces storage
367
costs. The reduced weight of pellets also results in the costs of transport being up to seven
times lower in comparison to the transport costs of the original raw material. It may be stored
for a longer period, since it has a lower moisture content and is resistant to natural
putrification processes, in contrast to raw biomass. Pellets have a smooth surface, which well
protects them against moisture absorption from the air. Increased interest in wood pellets
observed in Poland, due to the energy and utility value, has also resulted in an increased
demand for heating boilers fueled by wood pellets. There are approx. 20 producers and
importers of these boilers on the market. Their offer is varied in terms of the class of this
equipment, power, efficiency and price. Gross prices of Polish boilers range from 12 000 z
for boilers with a power of 15 kW to 30 000 z for boilers with a power of 100 kW (Tabert,
Popyk 2009). Boilers fueled by wood pellets are characterized on average by a two-fold
higher efficiency than that of coal-fueled ones.
CONCLUSIONS
Wood pellets are attractive substitutes of traditional fuels, despite their lower calorific
value. Effective cost of generating 1 kWh from wood pellets is lowest. The amount of 2.1 kg
wood pellets is an equivalent of 1 l of fuel oil, while 1.4 t wood pellets are equivalent of 1 t of
hard coal. It is an environmentally friendly fuel, as it emits practically no pollutants harmful
for the environment. Wood pellets are convenient in transport, storage and use. They are most
suitable for small heating installations, such as boiler rooms in small service and production
workshops (e.g. bakeries) or detached houses.
REFERENCES
1. KRY OWICZ A., CHRZANOWSKI K., USIDUS J. 2004: Sposób wytwarzania
energii elektrycznej i cieplnej oraz biometanu z biomasy z upraw celowych.
GLOBEnergy 4: 5-7.
2. STOLARSKI M., SZCZUKOWSKI S., TWORKOWSKI J. 2007: Charakterystyka
wybranych biopaliw z biomasy sta ej, Wydawnictwo Uniwersytetu Warmi skoMazurskiego, Problemy In ynierii Rolniczej, Olsztyn 4: 21-26.
3. TABERT M., LIS W. 2009: Bioenergy from wood waste. Annual Bulletin of Plant Economic Department of the European Wood Technology University Studies, Pozna
25: 141-144.
4. TABERT M., POPYK W. 2009: Heating equipment furled by wood pellets. Annual
Bulletin of Plant - Economic Department of the European Wood Technology
University Studies, Pozna 25: 144-149.
5. http://www.ure.gov.pl
6. http://www.pellets.pl/pellets/energia_drzewna.php
368
Streszczenie: Ekonomiczne korzyĞci wytwarzania bioenergii z odpadów drzewnych. W
artykule przedstawiono technologi wytwarzania granulatu drzewnego na przyk adzie linii
produkcyjnej o redniej wydajno ci oraz scharakteryzowano podstawowe parametry granulatu
drzewnego w zale no ci od rodzaju surowca. Wyznaczono ekonomiczne i ekologiczne
korzy ci wytwarzania energii z odpadów drzewnych. Wykazano, e granulat drzewny, jako
paliwo cechuje si niskim kosztem pozyskania jednej kWh energii (bioenergii) w porównaniu
do innych powszechnie stosowanych paliw.
Marek Tabert, Wojciech Lis,
Department of Economics and Wood Industry Management, Poznan University of Life Sciences
ul. Wojska Polskiego 38/42
(Ann. WULS–SGGW, For and Wood Technol. 72, 2010)
Biometrical characteristics of mature pine stands differing in terms of
quality, growing under site conditions of fresh mixed coniferous forest
A. TOMCZAK, T. JELONEK, M. RUTKOWSKI
Poznan University of Life Sciences, Faculty of Forestry, Department of Forest Utilization
Abstract: Biometrical characteristics of mature pine stands differing in terms of quality, growing under site
conditions of fresh mixed coniferous forest Analyses were conducted on two experimental plots, established in
stands with similar taxation characteristics, differing in terms of their technical quality index. On each of them
selected biometric traits were measured on all trees, i.e. diameter at breast height, height, height of the first snag
and the first live branch on the stem as well as the average crown width was determined. It was found that at a
similar number of trees per unit area trees from B3 in comparison to trees from B2 were characterised by a bigger
diameter at breast height and height, and a wider and longer crown. Except for the relative crown length,
observed differences were not statistically significant. No distinct trend was shown, differentiating stands on the
basis of biometrical characteristics. No similar dependence was found when analysing biometrical traits of trees
in quality and dimensional classes B and C. In case of classes A and C most biometrical traits turned out to be
statistically significantly different.
Keywords: Scots pine, biometrical characteristics, technical quality, fresh mixed coniferous forest
INTRODUCTION
In forest utilization the estimation of the amount and quality of timber constitutes an
element of preparatory work, preceding timber harvesting. In mature stands the most
commonly applied method is the time-consuming measurement of diameter at breast height
on all trees together with the classification of each of the trees to quality and dimensional
class.
Currently information technologies offer a possibility to apply modern measurement
methods, fast access to data and their on-going updating. The development of a system in
quality control estimation, based on the new generation tools, will probably be one of the
elements considerably facilitating management of a forest economy unit. It is assumed that
such a system has to be based on such traits of trees or stands which are easily measurable.
An optimal solution seems to use the already existing data bases containing stand
descriptions, including average height and diameter at breast height as well as a defined
technical quality. In the opinion of Król [2006] traits of the stem and crown are closely
correlated with timber quality. On the basis of his studies that author proved that in mature
pine stands these include e.g. crown projection area and crown length. Thus it seems justified
to conduct a comprehensive analysis combining traits of stems and crowns of trees with
technical quality, particularly in reference to the quality and dimensional classification of
round wood, currently binding and applied in practice.
On the basis of the stand description of the Babki Forest Division a data base was
created, containing the characteristics of all mature pine stands. Next two stands were
selected, characterized by an identical quality and stocking, similar age and a similar diameter
at breast height and height. The differentiation between these stands was based on technical
quality (tab. 1).
370
Table 1. Description of the study sites
symbol
area
species
[ha]
composition
B2
9,26
So
B3
2,34
So
age
95
90
stand
density
0,8
0,8
d1,3
[cm]
34
33
height
[m]
27
26
quality
class
I
I
technical
quality
2
3
In selected stands one representative mean sample plot each was established at an area
of 0.5 ha. In each of these plots all trees were numbered in succession. Next stem parameters
(d1,3 - diameter at breast height, h - height) and crown parameters (hpk – height of the base of
the live crown, dk - diameter of crown projection) were measured and each of them was
subjected to quality and dimensional classification [PN-92/D-95017]. Moreover, height of the
first snag on the stem (ht) was determined. On the basis of measurements of crown diameter
the projection area (pk) was calculated for each of them. All the data were subjected to
statistical analysis, determining the basic measures of the position and dispersion of traits.
Significance of differences between groups, due to a lack of normal distribution of traits, was
tested using non-parametric statistics.
RESULTS
The number of trees on the model areas was very similar (tab. 2). The value of the
calculated stocking density index according to Reinekie (SDI) for the stand with the model
area B2 was 462, while for the stand from plot B3 it was 463. Despite the comparable number
of trees per unit area, trees coming from B3 were thicker (d1,3) and taller (h). However, the
observed differences were not statistically significant.
Trees from B3 had relatively longer crowns with a bigger diameter, and the first snag
was located lower in comparison to trees from plot B2 (tab. 2).
Table 2. Selected quantitative traits of stems and crowns of trees
d1,3 [cm]
h [m]
hk:h*
dk
n
x
sd vc
x
sd vc
x
sd
vc
x sd
vc
x
B2 157 31,9 5,4 16,9 23,8 2,6 10,9 0,24 0,08 35,4 4,2 1,1 26,9 14,5
B3 151 32,6 5,1 15,6 24,1 2,8 11,7 0,27 0,10 35,5 4,4 1,2 27,1 16,4
n – number of cases; x – mean; sd – standard deviation; vc – variability coefficient
* - marked effects are significant with p<0,05
pk
ht:h
sd vc
x
sd
vc
7,8 53,6 0,34 0,13 37,8
9,0 54,8 0,30 0,11 35,7
The proportion of timber in the quality and dimensional classes A, B and D was higher
on plot B2, by 4.2, 15.1 and 0.7%, respectively. In reference to class C, it was found that its
proportion was by 19.9% higher in B3 (Fig. 1).
Fig. 1. Proportions of
timber in quality and
dimensional classes
54,8
60,0
50,0
share [%]
39,7
37,1
40,0
30,0
20,0
17,2
12,1
10,0
15,9 15,2
7,9
0,0
A
B
C
quality and dimensional classes
D
B2
B3
Between trees from the compared areas, which were classified to the same quality and
dimensional classes differences were found for most analyzed traits. In class A trees from B2
371
were thicker and taller, while in B, C and D it was trees from plot B3. Relatively longer
crowns were found for trees grown in B3, while in reference to class A relative crown length
was the same both in B2 and in B3. Except for class A, wider crowns were formed by trees
from B3. Relative height of the first snag on the stem in B2 was lower only in case of class A
(tab. 3, tab. 4).
Table 3. Selected quantitative traits of stems and crowns of trees in quality and dimensional classes in plot B2
KJW
n
A
B
C
D
19
86
27
25
d1,3 [cm]
h [m]
x
sd
vc
x
sd
39,32 3,7 9,3 25,52 2,0
31,1 3,2 10,2 23,8 2,4
30,72 7,6 24,7 23,12 3,3
30,5 5,8 18,9 23,4 2,5
vc
x
7,7 0,26
10,1 0,24
14,3 0,231
10,5 0,24
hk:h
sd
0,07
0,07
0,11
0,10
vc
27,6
31,7
47,5
39,9
x
5,02
4,1
4,02
4,0
dk
sd
1,1
1,0
1,4
1,0
vc
21,6
24,3
34,3
25,5
x
20,8
13,7
14,01
12,8
pk
sd
8,5
6,6
9,4
7,2
vc
x
41,1 0,32
48,0 0,351
66,9 0,331
56,1 0,32
ht:h
sd
0,10
0,12
0,16
0,14
vc
32,9
34,2
47,3
43,2
n - number of cases; x - mean; sd - standard deviation; vc - variability coefficient
1
- differences between B2 and B3 statistically significant at p<0,05
2
Table 4. Selected quantitative traits of stems and crowns of trees in quality and dimensional classes in plot B3
KJW
n
A
B
C
D
12
60
56
23
d1,3 [cm]
x
sd
vc
x
36,02 5,9 16,3 23,92
32,5 5,0 15,4 24,4
32,82 5,0 15,4 24,22
30,9 4,3 13,9 23,5
h [m]
sd
2,1
2,6
3,2
2,7
vc
x
8,6 0,26
10,9 0,29
13,2 0,261
11,6 0,27
hk:h
sd
0,07
0,11
0,09
0,08
vc
27,3
37,8
34,8
30,4
x
4,52
4,5
4,42
4,1
dk
sd
1,1
1,4
1,1
1,0
vc
25,6
29,9
25,3
23,1
pk
ht:h
x
sd
vc
x
sd
16,6 7,9 47,8 0,34 0,14
17,6 10,9 61,9 0,331 0,09
16,01 7,6 47,5 0,291 0,11
14,0 6,8 48,5 0,27 0,13
vc
40,9
26,7
38,0
48,1
n – number of cases; x – mean; sd – standard deviation; vc – variability coefficient
1
2
CONCLUDING REMARKS
Among the analyzed quantitative traits of stems and crowns of trees, growing in stands
differing in terms of their technical quality index, statistically significant differences were
found only in case of the relative length of the crown. On average longer and wider crowns
were recorded for trees from plot B3, which is an observation consistent with the proposals
presented by Pazdrowski [1994] and Król [2006]. They stated that trees with wider and longer
crowns are characterized by lower quality stems. This phenomenon is probably connected
with the process of self-pruning, which depending on tree growth and development conditions
is more or less dynamic [Jelonek et al. 2006, 2008].
As it could have been expected, the proportion of trees of high quality (classes A and
B) was higher in plot B2. Under site condition of fresh mixed coniferous forest, which is an
optimal site for Scots pine, differentiation in stand quality may result from various causes.
Timber quality is determined by genetic factors and by growth and development conditions of
trees [Paschalis 1980; Jakubowski et al. 2005], particularly significant anthropogenic
pressure. In case of mature stands it is practically impossible to review the past conditions and
tending interventions.
Analyses did not show a marked trend, which would differentiate stands on the basis
of biometric traits of trees (a statistically significant difference was found only in reference to
the relative length of the crown). In quality and dimensional classes statistically significant
differences were found for most analyzed traits only in classes A and C.
REFERENCES
1. JAKUBOWSKI M., TOMCZAK A., JELONEK T., PAZDROWSKI W. 2005. Radial
variability of the strength quality coefficient of Scots pine (Pinus sylvestris L.) wood
in relation to the tree biosocial position in the stand. EJPAU 8 (3) #08.
372
2. JELONEK T., PAZDROWSKI W., TOMCZAK A., STYPU A I. 2006. Analysis of
the quality of pine sawmill wood set against tree biosocial classes in the tree stand.
Ann. Warsaw Agricult. Univ. SGGW, For. And Wood Technol. 58: 372 378.
3. JELONEK T. , PAZDROWSKI W., TOMCZAK A., SZABAN J. 2008. The effect of
social position of a tree in the stand and site on wood quality of Scots pine (Pinus
sylvestris L.). EJPAU 11 (2) #10.
4. KRÓL T. 2006. Wybrane cechy ilo ciowe koron drzew, a jako techniczna drewna
sosny zwyczajnej (Pinus sylvestris L.) z drzewostanów r bnych. Praca doktorska.
Katedra U ytkowania Lasu, Pozna .
5. PASCHALIS P. 1980. Zmienno jako ci technicznej drewna sosny pospolitej we
wschodniej cz ci Polski. Sylwan 124 (1):
6. 29 43.
7. PAZDROWSKI W. 1994. Korona drzewa jako kryterium oceny jako ci drewna sosen
z drzewostanów r bnych. Pr. Kom. Nauk Roln. Kom. Nauk Le n. PTPN 78: 149 155.
8. PN-92/D-95017. Surowiec drzewny. Drewno wielkowymiarowe iglaste. Wspólne
wymagania i badania.
Streszczenie: Charakterystyka biometryczna dojrzaáych drzewostanów sosnowych
zróĪnicowanych pod wzglĊdem jakoĞci, wyrosáych w warunkach siedliskowego typu lasu
BMĞw Analizie poddano dwie powierzchnie do wiadczalne, za o one w drzewostanach o
zbli onych cechach taksacyjnych, zró nicowane pod wzgl dem wska nika jako ci
technicznej. Na ka dej z nich pomierzono wybrane cechy biometryczne wszystkich drzew, tj.:
pier nic , wysoko , wysoko po o enia na pniu pierwszego tylca i ywej ga zi oraz
okre lono przeci tn szeroko korony. Stwierdzono, e przy zbli onej liczbie drzew na
jednostce powierzchni drzewa z B3 charakteryzowa y si w porównaniu do drzew z B2
wi ksz pier nic i wysoko ci , szersz i d u sz koron . Z wyj tkiem wzgl dnej d ugo ci
korony, zaobserwowane ró nice nie by y jednak statystycznie istotne. Nie wykazano
wyra nego trendu, ró nicuj cego drzewostany na podstawie cech biometrycznych. Podobnej
zale no ci nie stwierdzono analizuj c cechy biometryczne drzew w klasach jako ciowo –
wymiarowych B i C. W przypadku klas A i C wi kszo cech biometrycznych wykaza a
statystycznie istotne ró nice.
Poznan University of Life Science
Department of Forest Utilisation
ul. Wojska Polskiego 71A, 60 – 625 Pozna
Arkadiusz Tomczak, PhD ([email protected])
Biometrical characteristics of mature pine stands differing in terms of
quality, growing under site conditions of fresh mixed broad-leaved forest
A. TOMCZAK, W. PAZDROWSKI, T. JELONEK
Poznan University of Life Sciences, Faculty of Forestry, Department of Forest Utilization
Abstract: Biometrical characteristics of mature pine stands differing in terms of quality, growing under site
conditions of fresh mixed broad-leaved forest In was attempted in this study to characterise two stands with
similar taxation characteristics, differing in terms of their technical quality index. On experimental plot L3
(technical stand quality index - 3) trees were characterised by a generally bigger diameter at breast height, lower
height, longer and wider crowns and had less pruned stems. Observed differences, except for relative height of
the first snag on the stem, were statistically significant. It was of interest that a high proportion of timber classes
A and B was found on plot L2. Fresh mixed broad-leaved forest is not an optimal site for Scots pine. Thus this
result has to be verified on the basis of further studies.
Keywords: Scots pine, biometrical characteristics, technical quality, fresh mixed broad-leaved forest
INTRODUCTION
Technical quality is an element in the stand description of mature stands. It is defined,
among other things, on the basis of the minimum, average diameter at breast height outside
bark. Moreover, the minimum length of the buttress with no defects and the proportion of
trees meeting this condition are also considered. The determined index is, among other things,
a reflection of silvicultural measures affecting many morphological traits of trees and stands.
In tending interventions, particularly thinning, the crown is a significant criterion in
tree evaluation. It facilitates e.g. the evaluation of vitality and growth trends at all
development phases of trees [Jaworski 2004]. The size of the crown, specifically its length,
affects increment in diameter. In the opinion of Król [2006] it is also correlated with timber
quality. From the economic point of view specific traits of tree stems have a permanent effect
on the value of timber. Leibundgut [1972] expressed an opinion that quality requirements for
timber in the distant future may not be forecasted. However, this objection is treated as
justified only in relation to the evaluation of the importance of individual quality attributes,
since irrespective of the practical purpose most quality traits will always be unchanged. Only
their importance changes, which varies at individual methods of wood utilisation and the
proportion of high quality assortments is an important element in the revenue of a forest
economy unit. This argument is confirmed in view of the current forestry policy, treating
production quality as one of many priorities.
In view of these facts it seems justified to conduct a comprehensive analysis
combining easily measurable traits of stems and crowns of trees with technical quality,
particularly in reference to the quality and dimensional classification of round wood, currently
binding and applied in practice.
The selection of model stands was based on a data base, which was created on the
basis of stand description for mature pine stands in the Babki Forest Division. Two stands
were selected, being identical in terms of their quality and stocking, similar in age, similar in
average diameter at breast height and height, and differing in terms of their quality indexes
(tab. 1).
374
Table 1. Description of the study sites
symbol
area
species
[ha]
composition
L2
5,79
So
L3
2,25
So
age
99
89
stand
density
0,8
0,8
d1,3 [cm]
37
36
height
[m]
28
26
quality
class
I
I
technical
quality
2
3
Within each the selected stands one representative mean sample plot was established
at an area of 0.5 ha. In each of the plots all trees were numbered in succession. Next stem
parameters (d1,3 - diameter at breast height, h - height) and crown parameters (hpk – height of
the base of the live crown, dk - diameter of crown projection) were measured on each of them.
Moreover, the height of the first snag on the stem (ht) was also recorded. On the basis of
crown diameter measurements their projection area (pk) was calculated. Each of the trees was
classified also in terms of their quality and dimensions [PN-92/D-95017].
Collected data were subjected to statistical analysis, defining basic measures of the
position and dispersion of traits. Significance of differences between groups, due to a lack of
normal distribution of traits, was tested using the non-parametric statistics.
RESULTS
On the model plots the number of trees was similar (tab. 2). The stocking density
index according to Reinekie (SDI) for the stand, in which the representative plot L2 was
established, was 456, while for the stand with plot L3 it was 548. Despite the fact that the
number of trees per unit area was comparable and the SDI value was markedly higher, trees
coming from L3 were thicker (d1,3). However, the recorded difference was not statistically
significant. Similarity as in case of height, this time in L3 trees were on average lower than
those coming from L2 by 1.2 m (tab. 2).
Table 2. Selected quantitative traits of stems and crowns of trees
d1,3 [cm]*
h [m]*
hk:h*
dk*
pk*
ht:h
n
x
sd vc
x
sd vc
x
sd
vc
x sd
vc
x
sd
vc
x
sd
vc
L2 136 34,5 4,9 14,1 26,0 2,3 8,9 0,25 0,07 27,4 4,3 0,9 21,6 15,0 6,8 45,2 0,28 0,09 33,1
L3 141 37,9 6,8 18,1 24,8 3,2 12,7 0,33 0,09 26,1 4,9 1,3 27,0 20,0 10,5 52,4 0,24 0,12 49,4
* - marked effects are significant with p<0,05
The proportion of individual quality and dimensional classes of timber differed
markedly for the analysed plots. It was stated that in plot L2 the proportion of class A was
39.7%, class B - 44.9%, which in relation to plot L3 were values higher by 22.7% and 10.9%,
respectively. In case of classes C and D an opposite dependence was found. In L2 in relation
to L3 the proportion of class C was lower by 22.3%, while for class D it was by 11.2% (Fig.
1).
50,0
Fig. 1. Proportions of
timber in quality and
dimensional classes
44,9
39,7
share [%]
40,0
34,0
32,6
30,0
20,0
17,0
16,3
10,3
10,0
5,1
0,0
A
B
C
quality and dimensional classes
D
L2
375
L3
When comparing quantitative traits of stems and crowns between individual
experimental plots it was stated that on L3, irrespective of the quality and dimensional class,
trees were thicker (d1,3), while in classes B, C and D they were lower (h). Trees grown in plot
L2 were characterised by relatively shorter crowns of a smaller diameter. It was also stated
that the relative height of the first snag on the stem was higher in trees from class A in plot L3,
while in the other classes it was in trees on plot L2 (tab. 3, tab. 4).
Table 3. Selected quantitative traits of stems and crowns of trees in quality and dimensional classes in plot L2
KJW
A
B
C
D
d1,3 [cm]
h [m]
x
sd
vc
x
sd
54 38,2 3,5 9,1 26,12 2,5
2
61 31,4 3,7 11,9 25,6 1,9
14 34,82 5,1 14,5 27,02 3,3
7 32,72 2,8 8,5 25,9 1,7
n
vc
x
9,5 0,271
7,5 0,23
12,1 0,281
6,5 0,261
hk:h
sd
0,08
0,05
0,06
0,07
vc
29,4
23,7
22,2
26,3
x
4,62
4,02
4,5
4,22
dk
sd
1,0
0,8
0,8
0,8
vc
22,0
20,1
18,6
18,6
x
17,21
12,9
16,5
14,11
pk
sd
7,9
5,3
6,5
5,0
vc
x
46,0 0,281
40,7 0,29
39,6 0,27
35,4 0,27
ht:h
sd
0,10
0,10
0,05
0,11
vc
35,5
32,4
19,1
42,1
1
- differences between L2 and L3 statistically significant at p<0,05
2
Table 4. Selected quantitative traits of stems and crowns of trees in quality and dimensional classes in plot L3
KJW
n
A
B
C
D
24
48
46
23
d1,3 [cm]
x
sd
vc
x
43,5 5,1 11,8 26,32
36,1 5,3 14,7 24,42
36,82 7,0 18,9 24,72
37,92 8,2 21,5 24,2
h [m]
sd
3,3
3,2
3,2
2,4
vc
x
12,5 0,351
13,3 0,33
13,0 0,331
9,7 0,341
hk:h
sd
0,08
0,08
0,09
0,11
vc
24,2
23,8
26,9
31,6
x
6,02
4,82
4,5
4,72
dk
sd
1,2
1,2
1,0
1,7
vc
19,3
24,1
23,0
35,5
pk
ht:h
x
sd
vc
x
sd
29,31 10,9 37,2 0,331 0,11
19,1 9,5 49,7 0,28 0,09
16,4 7,3 44,5 0,19 0,12
19,31 12,2 63,4 0,16 0,10
vc
32,4
30,4
61,2
61,6
1
2
CONCLUDING REMARKS
Plots on which measurements were taken were characterised by a low stocking density
index (SDI < 600), with its higher value found for L3. Trees grown in this stand were thicker
(at breast height – d1,3) and at the same time lower in classes B, C and D, in comparison to
trees older by 10 years from plot L2. They had wider and longer crowns and they were less
pruned. The size of the crown is correlated with the dynamics of tree increment [Lemke 1966;
Zaj czkowski 1973], which according to Pazdrowski [1992] is in turn connected with the
quality of their stems at cutting age. Trees, which at young age increase in diameter more
dynamically, supply lower quality timber.
Analysis conducted in this study, combining traits of stems and crowns of trees with
technical quality, in relation to the quality and dimensional classification of round wood,
currently binding and applied in practice, showed a statistically significant difference between
selected quantitative traits. The observed differentiation between L2 and L3, despite a
comparable number of trees per area unit, was probably the effect of different growth and
development conditions of trees at young age (spacing, intensity of tending intervention). It
may also be assumed that it is an effect of genetic variation, particularly characteristic of
Scots pine [Giertych, Oleksyn 1992; Kosi ska et al. 2007]. Trees respond to changes, which
occur in their environment [Oleksyn et al. 1998]. Through long-term evolution populations
have developed within species, adapted to local growth and development conditions. Transfer
of plant material in locations with relatively different conditions may result in the expected
production results being unsatisfactory [Barzdajn 2006].
It is of interest that a high proportion of timber classes A and B was found in plot L2.
Fresh mixed broad-leaved forest is not a recommended site type for Scots pine culture.
Conditions with a relatively high moisture content usually do not promote production of pine
376
timber of high quality. Thus this result has to be verified on the basis of a bigger number of
experimental plots.
REFERENCES
1. BARZDAJN W. 2006. Zmienno cech taksacyjnych sosny zwyczajnej (Pinus
sylvestris L.) polskich pochodze w do wiadczeniu proweniencyjnym z 1985 roku w
Nadle nictwie Zielonka. Sylwan, 150 (1): 8 19.
2. GIERTYCH M., OLEKSYN J. 1992. Studies on genetic variation on Scots pine
(Pinus sylvestris L.) coordinated by IUFRO. Silvae Genetica, 41 (3): 133 143.
3. JAWORSKI A. 2004. Podstawy przyrostowe i ekologiczne odnawiania i piel gnacji
drzewostanów. PWRiL, Warszawa.
4. KOSI SKA J., LEWANDOWSKI A., CHA UPKA W. 2007. Genetic variability of
Scots pine maternal populations and their progenies. Silva Fennica 41 (1): 5 12.
5. KRÓL T. 2006. Wybrane cechy ilo ciowe koron drzew, a jako techniczna drewna
sosny zwyczajnej (Pinus sylvestris L.) z drzewostanów r bnych. Praca doktorska.
Katedra U ytkowania Lasu, Pozna .
6. LEIBUDGUT H. 1972. Piel gnowanie drzewostanów. PWRiL, Warszawa.
7. LEMKE J. 1966. Korona jako kryterium oceny dynamiki wzrostowej drzew w
drzewostanie sosnowym. Fol. For. Pol., Ser. A. 12: 185 211.
8. OLEKSYN, J., TJOELKER, M. G., REICH, P. B. 1998. Adaptation to changing
environment in Scots pine populations across a latitudinal gradient. Silva Fennica, 32
(2): 129 140.
9. PAZDROWSKI W. 1992. Jako drewna k ód odziomkowych r bnych sosen a
dynamika przyrostu grubo ci w kolejnych pi cioletnich okresach ycia drzew.
Sylwan,136 (8): 35-45.
10. PN-92/D-95017. Surowiec drzewny. Drewno wielkowymiarowe iglaste. Wspólne
wymagania i badania.
11. ZAJ CZKOWSKI J. 1973. Przyrost mi szo ci w klasach biosocjalnych starszych
drzewostanów sosnowych. Sylwan, 117 (11): 1 9.
Streszczenie: Charakterystyka biometryczna dojrzaáych drzewostanów sosnowych
zróĪnicowanych pod wzglĊdem jakoĞci, wyrosáych w warunkach siedliskowego typu lasu
LMĞw W pracy podj to prób scharakteryzowania dwóch drzewostanów o zbli onych
cechach taksacyjnych, zró nicowanych pod wzgl dem wska nika jako ci technicznej. Na
powierzchni do wiadczalnej L3 (wska nik jako ci technicznej drzewostanu - 3) drzewa
cechowa y si generalnie wy sz pier nic , ni sz wysoko ci , d u szymi i szerszymi
koronami oraz posiada y s abiej oczyszczone pnie. Zaobserwowane ró nice, z wyj tkiem
wzgl dnej wysoko ci po o enia na pniu pierwszego tylca, by y statystycznie istotnie.
Interesuj cy fakt stanowi równie wysoki udzia surowca klasy A i B na powierzchni L2.
LM w nie jest optymalnym siedliskiem dla sosny zwyczajnej. Wynik ten musi by zatem
zweryfikowany na podstawie dalszych bada .
Author’s address:
Poznan University of Life Science
Department of Forest Utilisation
ul. Wojska Polskiego 71A, 60 – 625 Pozna
Arkadiusz Tomczak, PhD ([email protected])
Forestry and Wood Technology No72, 2010: 378-381
(Ann. WULS-SGGW, For and Wood Technol. 72,2010)
Study on the application of different types of roof trusses in wooden
constructions
ANDRZEJ TOMUSIAK
Department of Construction and Technology of Final Wood Products Warsaw University of Life SciencesSGGW.
Abstract: Study on the application of different types of roof trusses in wooden constructions.
The study analyses the possibilities of using different types of roof trusses in wooden constructions. Such
parameters as the usage of timber, the usage of gang nail connector plates and the value of forces in the truss
elements were taken into consideration. The results of the study proved that the most useful type of truss for
framing constructions is the FINK truss.
Keywords: truss, gang nail connector plate, timber, wood
INTRODUCTION
Roof trusses with gang nail connector plates are getting more and more popular in roof
constructions. The reasons include their fast design [1,2], manufacture [3] and assembly at the
construction site. Another doubtless advantage of such constructions is their cheapness.
OBJECT OF THE STUDY
The purpose of the study was to examine the possibility of using different types of
trusses in timber roof constructions. The starting point for the study was:
- the amount of timber used for the construction
- the amount of gang nail connector plates used
- the maximum forces acting on the elements of the truss.
Within the scope of the study there is:
- the choice of trusses for analysis
- adopting project assumptions
- calculating the internal forces and designing the cross sections of the truss
elements
- designing the surface of the gang nail connector plates.
PROJECT ASSUMPTIONS
The trusses chosen for the purpose of the study were those used when the attics were
not habitable. Therefore, the trusses used were as on the figure 1. Such trusses, according to
the sources [2] are the most used.
378
A
B
C
D
Figure.1 The trusses that were subject of the analysis: A – FINK, B – with vertical posts, C- with four diagonal
members, D – “M” type
The trusses involved in the study were 8m, 10m and 12m wide. The pitch angle of the
roof surface was the same in all types of trusses and amounted to 19 degrees – this is the
angle which is the most frequently recommended [3]. Moreover, it was assumed that in the
bottom chord there would be a suspended ceiling, the roof covering would be made of steel
metal sheets, the spaces between truss units would be: 0.6m, the zone of snow load II [ PNEN 10/B- 02011], the zone of wind load I [ PN-EN 08/B – 02010]. The class of timber in all
the trusses was C27.
379
PROCESS OF THE STUDY
According to the rules of designing roof trusses, for the adopted assumptions, the
values of loads at the nodes from vertical load on the top chord, bottom cord, and for wind
load were calculated. Afterwards, the forces on the members were calculated for different
load schemes.
After summing them up, the forces on the members were obtained [3]. Subsequently, the
cross sections of the elements were planned, in accordance with the designing rules and the
applicable norms [3]. Finally, gang nail connector plate surfaces were designed.
RESULTS
The results are presented in the tables from 1 to 3.
Table 1. Listings of maximum force values in the truss members [kN] for truss types A, B.
Truss type
Span [m]
Member
G1
D1
K1
K’1
K2
K’2
8
A
10
12
8
B
10
12
-12,7
12,9
-2,2
-1,8
3,7
3,9
-15,9
16,1
-2,8
-2,4
4,7
5,0
-19,1
19,4
-3,3
-2,8
5,6
5,9
-13,1
13,3
-2,1
-1,8
5,9
6,3
-16,4
16,6
-2,6
-2,2
7,4
7,9
-19,7
20,0
-3,1
-2,6
8,9
9,5
Table 2. Listings of maximum force values in the truss members [kN] for truss types C, D.
Truss type
Span [m]
Member
G1
D1
K1
K’1
K2
K’2
8
C
10
12
8
D
10
12
-13,9
13,9
-2,2
-1,9
-1,4
-1,2
-17,8
17,8
-2,8
-2,5
-1,8
-1,6
-20,9
20,9
-3,3
-2,9
-2,1
-1,9
-13,2
13,3
0,8
0,8
-4,6
-4,0
-16,5
16,7
1,0
1,0
-5,7
-5,0
-20,0
20,0
1,2
1,2
-6,9
-6,1
Tab. 3. The amount of timber used for manufacturing one unit of the truss [m3] and the amount of Merit F gang
nail plates used [dm2] in each type of roof trusses.
Truss type
Span [m]
8
10
12
average
A
Timber
usage
[m3]
0,091
0,133
0,180
0,135
B
Nail
plate
usage
[dm2]
40,4
43,2
45,7
43,1
Timber
usage
[m3]
0,095
0,145
0,201
0,147
C
Nail
plate
usage
[dm2]
41,4
49,7
51,4
47,2
380
Timber
usage
[m3]
0,100
0,125
0,200
0,142
D
Nail
plate
usage
[dm2]
50,5
66,2
69,4
62,0
Timber
usage
[m3]
0,104
0,159
0,201
0,155
Nail
plate
usage
[dm2]
42,2
48,1
55,0
48,4
RESULT ANALYSIS
The calculations which were carried out showed that the usage of timber grows by
leaps and depends on the span of the truss units. However, for the 8m trusses, the A type has
the lowest usage of timber (0,091m3), whereas the D type has the highest usage of timber
(0,104m3), the difference being of 14%. For the trusses which are 10m and 12m wide, this
difference amounts to 11,7%. Taking into account the average timber usage for all the spans,
the smallest usage characterizes type A truss. The lowest usage of Merit F nail gangs occurs
with the truss type A – an average of 43,1dm2, and the highest usage occurs with the truss
type C- 62dm2, resulting in a difference of about 30%.
While comparing the maximum forces on the members, we may notice that they grow
together with the span, which is natural. However, for the same span, the smallest forces
characterize the truss type A, but the differences are small and amount to several percent.
CONCLUSIONS
On the basis of the study conducted, the following conclusions were drawn:
1. The lowest usage of timber is needed for the truss type A.
2. The surface of gang nail connector plates used for the joints of the elements in the
truss type A, was the smallest.
3. The maximum axial forces for the truss type A have the lowest value.
4. The study confirmed the most frequent and most extended application of FINK trusses
in wooden framing constructions of small cubature.
REFERENCES
1. KOTWICA J.2005:Konstrukcje drewniane w budownictwie tradycyjnym. Arkady,
Warszawa.
2. MIELCZAREK Z.1994:Budownictwo drewniane. Arkady, Warszawa.
3. NO Y SKI W.1994:Przyk ady oblicze konstrukcji budowlanych z drewna.
Wydawnictwa Szkolne i Pedagogiczne, Warszawa.
Streszczenie: Study on the application of different types of roof trusses in wooden
constructions. W pracy badano mo liwo ci wykorzystania ró nych typów wi zarów
kratowych w konstrukcjach drewnianych. Wzi to pod uwag zu ycie drewna ,p ytek
kolczastych, warto ci si wyst puj ce w elementach kratownic. Stwierdzono e najbardziej
przydatnym wi zarem w konstrukcjach szkieletowych jest wi zar typu FINCK.
Andrzej Tomusiak
Department of Construction and Technology of Final Wood Products
Szko a G ówna Gospodarstwa Wiejskiego
02-787 Warszawa, ul. Nowoursynowska 166
E – mail address: [email protected]
Poland
Conservation of wooden sculpture of saint Anne
A. TROCHIMOWICZ
Artist, art restorer
The wooden sculpture, originally primed
and polychromed, was for many years exposed to atmospheric influence. The external
technological layers – the priming and the paint layer were not preserved. The wood
deteriorated to a high degree. The process of conservation allowed for maintaining the
sculpture’s function as a relict and it’s reception as a work of art.
Abstract: Conservation of wooden sculpture of saint Anne.
Keywords: conservation of art object, wood, sculpture
The sculpture depicts saint Anne as an old stooping woman holding a book in her right
hand. It is carved out of a single block of lime wood. The figure is 126cm of height.
Unfortunately, the external technological layers – the priming, the paint layer, as well as
possible gilding – have completely withered. At the time when the conservation treatment was
undertaken, the sculpture resided in a shrine on S. Kostki Potockiego street in the Wilanow
district of Warsaw.
The hinder part of the figure was not sculpted, but deeply grooved which indicates that
it was originally intended to be attached to a wall. Some traits of grounding found in recesses
of the sculpture show that it was primed, and probably polychromed. Application of this
technology means that the piece was meant to be displayed inside a building.
The provenance of the sculpture is unknown. There is no knowledge of when and
where from it was brought to its present residence. Judging by the style it is a Silesian
baroque sculpture. It was certainly moved from its original place to a roadside shrine, and
adapted to be viewed from all sides with its back provisionally concealed by wooden planks.
It is very likely that it was one of the many works of art which were brought to Warsaw from
the Recovered Territories after World War II.
Placing the sculpture in an open shrine with only a roofing exposed it to environmental
fluctuations, which caused complete deterioration of its polychrome. Consecutive working of
rain, melting snow, and sun lead to humidifying, and then parchment of the glue priming
which resulted in its flaking and eventual loss, followed by cracking and degradation of the
wood. The condition of the sculpture testified to its exposure to long lasting humidity during
the Autumn and Winter seasons alternating with the dehydrating influence of the sun during
the Summer months. The humidified wood swelled, and then contracted as it dried which
caused cracking. This process, at first only concerning the external layers, in time penetrated
deeper into the wood. Damage caused by fungus and mould resulted in destruction of the
structure of wood (the base of the sculpture and the left arm of the figure). Water which
saturated the wood during the rainy Autumn season froze in Winter thereby extending in
volume, and causing its further cracking and delaminating. All the above mentioned processes
have contributed to destruction of the sculpture.
The bottom part of the original figure no longer exists. During the previous
conservation process it was replaced, and a structure holding the figure upright was
introduced.1 The extent of the damage: the altered surface of the wood, the cracks, and the
1
It is hard to determine when and by whom previous conservation works were done.
382
overall erosion of the wood caused by atmospheric influence renders impossible restoring the
piece to its original form. It was, therefore, decided to maintain the sculpture`s function as a
relict having performed the necessary conservation procedures which would also allow its
reception as a work of art. Following the conservation process, the sculpture is not to return to
its previous place.
Conservation work began with the disinfection of the object2. Beech wood pegs, about
5 mm in diameter, were pasted underneath the sculpture, which enabled the vertical
adjustment of the sculpture as well as determining the actual height of the figure. After that all
losses at the reverse side and in the place of feet of the sculpture were supplemented by linden
wood. Henkel Pattex glue was used for bonding. Major losses unfit for repairing and losses
larger than a few millimeters at the places of joints were filled with Axson SC 258 epoxy
paste3, used mainly in places where the wood has been leached by rainwater – i.e. on the left
shoulder and at the bottom of the sculpture.
The cavities in the left arm, in the folds of the robe on this arm, the right thumb, and in
the fold on the back side of the robe below the belt, and below the foot were filed with dry
lime-wood. Narrow strips of wood were inserted into the cracks on the saint’s head and on the
stomach4. Large supplements at the reverse side of the sculpture were fitted in the places
where the original surface was chopped down. Henkel Pattex glue was used for bonding.
Special emphasis was placed on removing the old wood thoroughly up to the healthy tissue
during the bonding process. Major wooden supplements adhered quite well to the original
surface, as they were pasted in the places where the wooden features were added during the
previous conservation intervention after the drastic alignment of the surface. The structure of
the degraded wood was strengthened during the pasting work by the use of the local injection
of Rohm&Hass B72 Paraloid solution in toluene at relatively low concentrations (5-10 %).
The treatment was repeated several times. Small fissures and connections between the
supplements and the original object were filled with ZAR Latex Wood Patch. The surface was
thereafter mechanically wet processed with the use of cork.
The base of the sculpture which was replaced during the previous conservation was
kept. Although it is made of a different kind of wood the outline of shoes is marked on its
surface. It was possibly carved when the original feet still existed. In the process of current
conservation, the size and the shape of the shoes served as basis for the reconstruction of the
feet.
After small fissures were filled and their surfaces processed the sculpture was coated
with 12% shellac solution in denatured alcohol. When dried, the retouch has been done with
Rembrandt acrylic paints. Maimeri retouching paints dissolved in Maimeri Solvent Forte were
used for a finishing touch. The entire surface of the sculpture was covered with Gualtiero
Meazza S.R.L. Novecento Legno liquid wax.
The sculpture which was to a large extent damaged, following the process of
conservation can once again be viewed as an object of art. The composition of the sculpture
was restored by filling in cavities and replacing damaged parts. It was decided that due to its
condition, as well as its value, the sculpture can no longer be displayed in the previous
location. Therefore, a mould was made and from it a cast in epoxy resin. This was painted to
imitate the wood of the original. The copy was placed in the shrine in Wilanów, and the
2
The preparation was chosen after mycological tests. The surface of the sculpture was covered with Altax
Boramon C 30.
3
Once dried, the epoxy paste used to fill losses can be processed or removed with the use of woodworking tools.
4
The carpentry work was performed by Wies aw Myd owiecki from the Conservation Workshop at the Royal
Castle in Warsaw.
383
original in the Historical Museum of Warsaw as a deposit. In the future, it will be displayed in
the Wilanow Townhouse.
a.
b.
c.
d.
II.1 Saint Anne of Wilanow. The front of the sculpture before and after conservation (a,b), the back of the
sculpture before and after conservation (c,d)
a.
b.
II.2 Saint Anne of Wilanow. A close-up of the left arm. Before conservation (a), and after conservation (b)
384
II.3. Saint Anne from Wilanow. A close-up of the sculpture during the process of insertion of wooden fillings
Streszczenie: Konserwacja drewnianej rzeĨby Ğw. Anny. Drewniana rze ba, pierwotnie
gruntowana i polichromowana by a nara ona na wieloletnie dzia anie zewn trznych
warunków atmosferycznych. Zewn trzne warstwy technologiczne – grunt i warstwa malarska
nie zachowa y si . Drewno silnie zerodowa o. Zakonserwowano rze b zachowuj c j w
formie reliktu. Wykonano niezb dne zabezpieczenia oraz uzupe niono form rze biarsk
umo liwiaj c odbiór obiektu jako dzie a sztuki.
Aleksandra Trochimowicz
Species of wood used in cradle structures
A. TROCHIMOWICZ1, I. SWACZYNA2
1
2
Artist, art restorer
Abstract: Species of wood used in cradle structures. Study of objects from the collections of the National
Museum, and the Royal Castle in Warsaw was conducted in order to examine the influence of cradling structures
on wooden painting supports. Species of wood used both in cradle structures, and in painting supports were
identified. The relationship between species of wood used, and the type of cradle structure were determined.
Keywords: Conservation of art objects, panel paintings, cradle
For centuries wood has served as support of painting. The greatest advantages of wood
were its strength and availability. Different kinds of native wood were used depending on the
location. In sixteenth century, panels made of exotic wood began to be used as painting
supports. From the very beginning, artists and artisans faced the challenge to maintain
planarity of the paintings. The priming and painting layers applied on the panel front
constituted a moisture barrier which made the board prone to warping. A typical example of
this are the icons.
Already in the Middle Ages, a variety of structures reinforcing and stabilizing the
board were applied to the panel back. Their function was to hold together the panel (for
example during transportation), as well as to conserve its planarity. Cradling is a great
invention of the eighteenth century. First introduced at the end of seventeenth century, it
became exceedingly popular in all of Europe, and continued to be widely used until the
middle of the twentieth century.
a.
b.
c.
Fig.1 Three kinds of cradle structures found in objects from collections of the National Museum in Warsaw:
a – flat cradle, b – vertical cradle, c – block cradle.
The cradle consists of slats glued along the grain, and of movable crossbars. The “flat
cradle” is the first form of a movable structure (Fig.1 a). It consists of flat, massive, evenly
spaced slats, the surface of which was often greater than that of the remaining surface of the
reverse. The glued on slats constitute a moisture barrier and the original backside of the
thinned plank is, therefore, more susceptible to distortions caused by environmental
fluctuations. The portion of the surface of the glued on elements began to be reduced. A
386
modification of the above mentioned cradle is “vertical cradle” (Fig.1b). The advantage of
this structure is thinner cross section of the slats. The next development in cradle structure
was replacing the slats with blocks which supported crossbars – the block cradle, also known
as the Italian cradle, which began to be used as from the middle of the twentieth century (Fig.
1c). In time, duralumin elements began to be introduced in to strengthen both the holders and
the slats. This reduced the portion of the glued surface, as well as of the covered area of the
reverse of the panel, thus eliminating susceptibility of wood to deformation. The usage of new
materials also reduced friction within the cradle structure.
In all, 53 objects from collections of The National Museum and of the King`s Castle in
Warsaw were examined (Fig.2). The research assessed the state of preservation of each object
– of the paint layer, of the wooden support, and of the cradle structure. Kinds of wood used in
supports and cradles were identified.1
The species of wood most commonly used as painting support is oak, identified in 37
objects. In 4 objects spruce was used for constructing the panel, in 4 objects – poplar, in 2
objects – walnut, in 2 objects – exotic wood, and the remaining 4 of the examined painting
supports are made of respectively: pinewood, fir, lime-wood and birch.
Majority of cradles are made of pinewood -14 objects, of oak - 13, and of spruce - 11.
Subsequently, 4 are made of alder, 3 of fir, 3 of mahogany, and 3 (one of each) are made of
two kinds of wood. Respectively: of mahogany and oak, of ash and oak, and of lime-wood
and oak.
Three types of cradle structures were found: the type with massive slats - 38 objects,
vertical cradle – 14, and 1 block cradle. The following kinds of wood are used in vertical
cradle: oak – in 8 structures, pinewood -in 2 structures, and in remaining 4 structures
respectively: ash, spruce, fir, and mahogany. Flat cradles are made of: pinewood –12, spruce
–9, oak – 5, alder – 4, fir – 2, mahogany – 2, poplar – 1. Three of the flat cradles are made of
combination of two kinds of wood: the fixed slots attached along the grain are made of ash,
and the crosswise movable slots of oak; the fixed slots attached along the grain are made of
mahogany, and the crosswise movable slots of oak; the fixed slots attached along the grain are
made of lime-wood, and the crosswise movable ones of oak. The one block cradle is made of
spruce.
A functional cradle can be defined as a complete structure where all the fixed slots are
glued to the support, and all the crosswise slots are movable. Of the 53 examined objects,
only 18 have a functional cradle structure. 12 of them are flat cradles, and 6 – vertical cradle.
This indicates high degree of fallibility of the structure. A conclusion can be drawn that
vertical cradles are more reliable. Of the 14 vertical cradles, 6 are functional (42.4%), while of
38 flat structures, only 12 (31.5%). The largest number of functional flat cradles – 6 are
mainly made of pinewood, 2 of oak, and one of each kind of wood, respectively: of spruce,
and of alder. Cradles made of combination of two kinds of wood: mahogany/oak, limewood/oak have also been identified as functional.
The largest number of cradles – 14 are made of pinewood; 13 of oak, 11 of spruce.
Other kinds of wood used are: fir, mahogany, alder, ash, poplar, and lime-wood. The vertical
cradle are mainly made of oak. 12 flat cradles are made of pinewood, and 9 of spruce. Out of
the total number of functional vertical cradles, half were made of oak, while all the functional
flat cradles were made of pinewood.
1
Macroscopic research of wooden species were made by Prof. I. Swaczyna, Warsaw University of Life Sciences
– SGGW, Faculty of Wood Technology and M.Sc., Eng., E. Je ewska, Academy of Fine Arts in Warsaw,
Faculty of Conservation and Restoration Work of Arts.
387
In vertical cradle, the species of wood was chosen for its hardness. Both, the fixed and
the movable slots were relatively narrow, with a nearly square cross section. They needed to
be resistant to deformations caused by the movement of the support in order for the structure
not to get blocked. In the case of flat cradles with the massive slots, it was more important
that the wood is less prone to deformation caused by environmental fluctuations as the surface
of the support covered by both, the fixed and movable slots is relatively large, and even slight
changes of their size would cause blocking of the structure. For this reason, soft wood was
preferred. This principle was not always observed, of course. The cradles were made by
carpenters who were not always sufficiently trained. Many cradles are not made with
understanding of how they should function. Availability was another important criterion of
choice of the wood species.
Fig. 2.
The
catalogue
number
M. Ob. 602
M. Ob. 580
M. Ob. 1419
M. Ob. 2413
M. Ob. 1713
M. Ob. 1206
158976
M. Ob. 2419
M. Ob. 1056
184237
M. Ob. 2436
M. Ob. 2317
M. Ob. 1948
M. Ob. 453
M. Ob. 1047
M. Ob 46
M. Ob. 1870
M. Ob. 2381
M. Ob. 1811
M. Ob. 1707
ZKW128165
M. Ob. 1209
ZKW/1993
ZKW 1096
M.Ob.2506
M.Ob.2483
M. Ob. 2693
164635
M. Ob. 1054
M.Ob.2691
M.Ob.337
M. Ob. 626
128837
ZKW/862
ZKW/4481
M. Ob. 1476
M. Ob. 1824
184756
M. Ob. 1961
M. Ob. 1727
Measurements
in centimeters
57x48x0,6
54x63x0,3
44x32,3x0,8
49,7x64,5x0,5
65x100,5x0,5
56x66x0,6
106x73,8x0,4
74x57x0,5
72x97x0,3
74x103x0,2-0,4
47x65x0,3
63x53x0,4
42,x62,5x0,4
59x67x1,1
72,7x104x0,6
64x96,5x0,5
62x85x0,5
32,5x37x?
48,4x62,3x0,3
52,5x68x0,7
78,5x105x0,7
39,6x59,4x0,3
82,5x53,2xo,6
57X74,5X0,5
43,5x58x0,5
109x70x0,5
39,5x30x0,4
61,5x62x0,7
24,2x19,4x0,4
59,3x73,5x0,3
96x85x0,7
68x58x1,7
41x27,5x0,9
123,5x93,5x0,5
32,5x27x0,3
37x25,7x0,5
62,5x85,5x0,5
53x40,5x2
76x119,5x0,5
55,5x68,7x0,5
No. of
planks
of panel
5
3
2
2
4
2
3
3
4
4
2
3
2
2
3
4
?
1
2
3
3?
2
3
4
2
4
1
3
2
?
?
?
1
4
1
1
3
1
3
3
Dating
Provenance
XVI
XVII
XVII
XVII
XVI
XVII
?
XVII
XVII
?
XVIII
XVII
italian
northern ,
northern
northern
northern
northern
copy
northern
northern
copy
northern
northern
northern
northern
copy
northern
italian
northern
northern
northern
northern
northern
italian
northern
northern
northern
northern
italian
northern .
northern
italian
italian
italian
northern
northern
copy
northern
italian
northern
copy
XVII?, XIX?
XIX
XIX/XX
XVI/XVII
XVI
XVII
XVII
XVI/XVII
XVII
XVII
XVIII
XVII/XVIII
XIX/XX
XVI
XVII
XVI
XVII
XVIII/XIX
XVII
XVI
XVI
XVI
XVII
XVII
XVII
XVII
XIX
XVII
388
FunctioKind of
Kind of
Type
wood in the wood in the nality
of
cradle
support
cradle
flat
poplar
pine
+
flat
oak
pine
+
flat
oak
pine
+
flat
oak
pine
+
flat
oak
pine
+
flat
oak
pine
+
flat
oak
pine
+
flat
oak
pine
flat
oak
pine
flat
oak
pine
flat
oak
pine
flat
oak
pine
flat
oak
spruce
+
flat
walnut
spruce
flat
oak
spruce
flat
oak
spruce
flat
exotic
spruce
flat
oak
spruce
flat
oak
spruce
flat
spruce
spruce
flat
oak
spruce
flat
oak
oak
+
flat
oak
oak
+
flat
oak
oak
flat
oak
oak
flat
oak
oak
flat
oak
alder
+
flat
fir
alder
+
flat
oak
alder
flat
walnut
alder
flat
lime-wood
fir
flat
poplar
fir
flat
poplar
poplar
flat
oak
mahogany
flat
oak
mahogany
mahogany/oak
flat
oak
+
lime-wood/oak
flat
oak
+
flat
poplar
ash/oak
vertical
oak
oak
+
vertical
oak
oak
+
M. Ob. 1608
M.Ob.2440
M. Ob, 1735
M. Ob. 1820
M. Ob. 1992
M. Ob. 2438
M. Ob. 1742
M. Ob. 1064
M. Ob. 105
M. Ob.2154
ZKW/2123/
ZKW
dep.FC/112
186925
67x114x0,7
89x57,5x0,5
42,2x34x0,5
35x46x0,5
41,5x58x1,2
58,4x80,5x0,8
45x78,8x0,7
30x41x0,6
71,5x56x0,9
69x55x1
105,5x73x0,3
42,7x32,5x0,4
3
3
1
1?
3
3
2
2
2
3
3
1
XVII
XVI
XVII
XVII
XVII
XVII
XVII
XIX
XVI
XVI?
XIX
XVII
northern
northern
northern
northern
northern
northern
northern
northern
italian
northern
northern
?
vertical
vertical
vertical
vertical
vertical
vertical
vertical
vertical
vertical
vertical
vertical
vertical
oak
oak
oak
oak
pine
oak
oak
exotic
spruce
spruce
oak
birch
oak
oak
oak
oak
oak
oak
pine
pine
fir
spruce
mahogany
ash
+
+
+
+
56x80x1,1
1
XVI
italian
block
spruce
spruce
-
REFERENCES
1. W. LESI SKI, Konserwacja zabytków sztuki, t. 1, Warszawa 1995
2. L. UZIELLI, Historical Overview of Panel-Making Techniques In Central Italy,[w:]
The Structural Conservation of Panel Paintings: Proceedings of a Symposium at The J.
Paul Getty Museum, April 1995, Los Angeles 1998, p. 110-135.
Streszczenie: Gatunki drewna stosowane w parkietaĪach. Badaj c wp yw konstrukcji
parkieta owej na drewniane pod o a malarstwa przebadano obiekty z Muzeum Narodowego
w Warszawie oraz Zamku Królewskiego w Warszawie. Zidentyfikowano gatunki drewna
podobrazi oraz konstrukcji. Ustalono najcz ciej stosowane gatunki drewna i ich u ycie w
zale no ci od typu konstrukcji parkieta owej.
Aleksandra Trochimowicz
Email: [email protected]
Microfibril orientation during cambial xylem derivatives differentiation in
stems of Scots pine trees grown under polluted environment
MIRELA TULIK1), ALEKSANDRA RUSIN2)
1)
2)
Division of Forest Botany, Warsaw University of Life Sciences – SGGW
Department of Tumor Biology, M. Sklodowska-Curie Memorial Center and Institute of Oncology
Abstract: The arrangement of microtubules during differentiation of tracheids in wood of pine trees grown
under polluted environment was examined. Using immunofluorescent staining of the microtubules the changes
of microtubules arrays were observed. In cambial region and in tracheids at the stage of radial cell enlargement
the microtubules were arranged randomly whereas during subsequent stage of differentiation changed rotatively
from a flat Z – helix to a steep S –helix. It was observed that in the samples collected from polluted site among
the tracheids of early wood the cells with abnormally thin or/and thick lignified secondary wall were observed. It
seems that this kind of cell wall structure abnormality could be connected with altered number of microfibril
layers deposited during a given orientation of rotating microtubules.
Keywords: air pollution, cambium, microfibrils, Scots pine, tracheids, wood
INTRODUCTION
It is generally assumed that cortical microtubules, one component of cytoskeleton
composed of tubulin dimers, control the orientation of new deposited cellulose microfibrils
(Ledbetter and Porter, 1963). It is also known that during formation of the secondary cell wall
of tracheids or fibers, the arrays of the cortical microtubules are well ordered and their
orientation changes progressively as the process of differentiation proceeds (Abe et al. 1995;
Funada et al. 1997). The orientation of cellulose microfibrils on the innermost surface of the
cell walls changes in a similar way to that of the cortical microtubules, what provide strong
evidence for the co-alignment of the cortical microtubules and the cellulose microfibrils
during formation of texture of the tracheids cell wall.
In conifers, the process of tracheids differentiation is categorized by following stages:
cambial cell division, radial cell enlargement, cell wall thickening, lignification and cell death
(Wodzicki, 1971). When the growth of radial dimension is ceased, the secondary cell wall
with well-ordered cellulose microfibrils is deposited on the inner surface of the primary wall.
With the onset of the secondary wall deposition, the process of lignification starts at the
middle lamellae, progressing to the primary and secondary wall. Then, the autolysis of
cytoplasmatic contents occurs and the mature tracheids are dead cells with thick, lignified cell
wall. Their secondary wall is made up of multiple layers called S1, S2 and S3. The S2 layer is
the thickest.
The external factors (air pollutions included) affect the cambial cell derivatives
differentiation (Zaj czkowski, 1996, Savidge, 1996, Tulik and Rusin, 2005). The aim of our
investigations, therefore, was to examine the changes in the array of cortical microtubules
during consecutive stages of wood formation in pines growing under environmental stress
conditions.
390
The pine forest stands were located in Miasteczko l skie, in southern part of Poland
in neighbourhood of zinc and lead smelting factory. The samples containing phloem,
cambium, differentiating tracheids and mature wood were taken at breast height (1.3m) from
stems of Scots pine trees (Pinus sylvestris L.) during the season of active cambial growth in
2003. The age of pines was 20-28 years. The samples were obtained from two forest stands.
The first was located in the most polluted area in Imielów forest district, and the second - in
Miko eska, the district free of air pollutants, which served as a control.
The orientation of microtubules was studied using method of immunolocalization of
tubulin.
Small blocks containing cambium, phloem and xylem derivatives were excised from
collected samples and treated as described elsewhere (Bohdanowicz et al. 2005). In brief,
tissue blocks were fixed with 4% paraformaldehyde, embedded in Steadman’s wax and
sectioned transversely, radially and tangentially at thickness of approximately 30 Pm with a
rotary microtome. Sections were stretched on glass slides, dewaxed and rehydrated. Tubulin
was stained with mouse anti E-tubulin (SIGMA-Aldrich) and antimouse FITC-conjugated
goat antibody. Nuclei were counterstained with 1 g/ml 4’,6’-diamidino–2-phenylindole
dihydrochloride (DAPI) in PBS. Specimens were mounted with DAKO fluorescent mounting
medium and observed under magnifications of x40 or x100 using Olympus AX80 fluorescent
microscope equipped with appropriate filters and CAMEDIA C4040 camera.
The microscopic examination of samples, taken from the trees grown in polluted and
control sites showed the successive changes in the orientation of microtubules starting from
the cambium to the mature tracheids (Fig. 1).
Cambial
cell
Stage of radial cell
enlargement
Stage of secondary cell wall deposition,
lignification and protoplast autolysis
Fig. 1. Scheme of the microtubules orientation during consecutive stages of tracheids differentiation.
The arrays of microtubules in the cambium and in differentiating tracheids, that were
at the stage of radial enlargement - when primary cell wall forms, were arranged at random,
both in samples from polluted and control sites (Fig. 2A, B).
391
Fig. 2. Tangential sections of Pinus sylvesris stem.
A. Randomly oriented microtubules in cambial cell in sample from polluted site.
B. Longitudinal orientation of the microtubules in differentiating tracheid during stage of radial cell enlargement
in sample from polluted site.
C. Helically arranged microtubules in differentiating tracheids during the stage of cell wall thickening and
lignification in sample from polluted site.
D. Transversely oriented microtubules during the stage of cell wall thickening and lignification in sample from
polluted site.
392
At the early stage of radial cell enlargement the predominant orientation of the
microtubules was longitudinal and it changes to transverse as the cell expansion proceeded. It
was also observed that the microtubules in the differentiating tracheids disappeared locally in
circular regions. It means that this is the region where intertracheal bordered pits could be
formed, eventually. Similar regions were observed in differentiating tracheids of Abies
sachalinensis (Abe et al. 1995) and Taxus cuspidata (Funada et al. 1997).
When the stage of tracheids enlargement ceased, the microtubules orientation changed
progressively from a flat helix to a steep Z-helix and then clockwise rotation was also noted
both in samples from polluted and control sites (Fig. 2C, D). This observation is agreed with
results published in papers concerning plant microtubules (see Nick, 2000). However, we
observed that in trees grown in environment polluted with heavy metals, among the tracheids
of early wood the cells with abnormally thin or/and thick lignified secondary wall were
observed. This kind of cell wall structure abnormality could be connected with altered number
of microfibril layers deposited during a given orientation of rotating microtubules. This
example indicates that the dynamics of the cortical microtubules reorientation could be altered
by unfavorable environmental factors, such as heavy metals pollution.
CONCLUSION
1. The successive changes in the orientation of microtubules during the primary and
secondary wall deposition are observed both in differentiating tracheids from control
and polluted environment.
2. The rotational changes of the microtubules orientation during secondary cell wall
deposition might have been modified by air pollutions.
It seems that studies concerning arrangement of microtubules during formation of secondary
cell wall of tracheids should be continued. The microtubules play an important role during
plant morphogenesis. Therefore, the control of the process of wood formation by
manipulation of microtubules might provide new tools to improve wood quality.
REFERENCES:
1. Abe H., Funada R., Imaizumi H., Ohtani J., Fukuzawa K., 1995: Dynamic changes in
the arrangement of cortical microtubules in conifer tracheids during differentiation.
Planta 197: 418-421.
2. Bohdanowicz J., Szczuka E., wierczy ska J., Sobieska J., Ko ci ska-Paj k M., 2005:
Distribution of microtubules during regular and disturbed microsporogenesis and
pollen grain development in Gagea lutea (L.) Ker.-Gaw. Acta Biol. Cracov. Ser.
Botanica 47(2): 89-96.
3. Funada R., Abe H., Furusawa O., Imizumi H., Fukazawa K., Ohtani J., 1997: The
orientation and localization of cortical microtubules in differentiating conifer tracheids
during cell expansion. Plant Cell Physiol. 38(2): 210-212.
4. Ledbetter M.C., Porter K.R., 1963: A “microtubule” in plant cell fine structure. J Cell
Biol. 19: 239-250
5. Nick P. (ed.)., 2000: Plant microtubules. Potential for Biotechnology. Springer, Berlin,
Heidelberg, New York.
6. Savidge, R. A., 1996: Xylogenesis, genetic and environmental regulation, a review.
IAWA J. 17(3): 269-310.
7. Tulik M., Rusin A., 2005: Microfibril angle in wood of Scots pine trees (Pinus
sylvestris) after irradiation from the Chernobyl nuclear reactor accident. Environ. Pol.
134: 195-199.
393
8. Zaj czkowski S., 1996., Changes in cambial activity and secondary xylem structure of
Pinus sylvestris L. associated with ageing. In: Paschalis P., Zaj czkowski S. (Eds.),
Biodiversity protection of Bia owie a Primeval Forest,. Fundacja Rozwój SGGW,
Warszawa, pp. 7-21
9. Wodzicki T.J., 1971: Mechanism of xylem differentitation in Pinus silvestris L. J.
Exp. Bot. 22: 670-687
ACKNOWLEDGEMENTS
The authors thank Prof. Stefan Zaj czkowski for helpful comments during preparation of this
paper.
This work was supported by Grant, in part, No 3 P06L 039 22 from the Polish State for
Scientific Research.
Streszczenie: Orientacja mikrotubul podczas róĪnicowania pochodnych kambialnych na
stornĊ drewna w pniach sosen (Pinus sylvestris L.) wyrosáych w zanieczyszczonym
Ğrodowisku. Orientacja mikrotubul, elementu cytoszkieletu, warunkuje orientacj mikrofibryl
celulozowych w cianie komórkowej cewek drewna sosny. Przeprowadzono badania na
próbkach obejmuj cych kambium i ró nicuj ce si drewno, pobranych z pnia g ównego sosen
(Pinus sylvestris L.) rosn cych w rodowisku zanieczyszczonym metalami ci kimi (w
bliskim s siedztwie huty cynku i o owiu, Miasteczko l skie) oraz w rodowisku czystym.
Obserwacje mikroskopowe przy u yciu techniki imunofluorescencyjnego wybarwiania
mikrotubul wykaza y, e ich uk ad zmienia si dynamicznie, zarówno u drzew rosn cych w
rodowisku czystym, jak i zanieczyszczonym. W komórkach strefy kambialnej obserwowano
nieuporz dkowany uk ad mikrotubul, który podczas post puj cych faz ró nicowania si
drewna ulega stopniowym zmianom. I tak, na pocz tku fazy wzrostu promieniowego
ró nicuj cych si cewek przyjmowa uk ad pod u ny, natomiast w ko cowym etapie tej fazy
mikrotubule przyjmowa y po o enie poprzeczne. Podczas kolejnej fazy ró nicowania si
drewna, czyli odk adania wtórnej ciany komórkowej, lignifikacji oraz autolizy protoplastu,
mikrotubule we wszystkich analizowanych próbkach tworzy y uporz dkowane szeregi, a ich
uk ad zmienia si z p askiej Z helisy do stromej S helisy i znowu p askiej helisy Z.
Zaobserwowano jednak e, e pomi dzy cewkami drewna wczesnego, w próbkach sosen
wyros ych w zanieczyszczonym rodowisku, wyst puj cewki z cienk i/lub grub cian
komórkow . T anomali dotycz c grubo ci ciany komórkowej cewek wi emy z
zaburzeniami dynamiki zmian orientacji mikrotubul, a mianowicie z mo liwo ci tworzenia
odmiennej liczby warstw mikrofibryl celulozowych podczas rotacyjnych zmian uk adu
mikrotubul.
1)
Division of Forest Botany
Nowoursynowska 159,
2)
Department of Tumor Biology
M. Sklodowska-Curie Memorial Center and Institute of Oncology
Wybrze e Armii Krajowej 15
44-101 Gliwice, Poland
Changes in wood basic chemical composition in Salix viminalis in a model
experiment
BOGUS AWA WALISZEWSKA1, W ODZIMIERZ PR DZY SKI1, TAMARA
CHADZINIKOLAU2, AGNIESZKA SPEK-D WIGA A1
1
2
Institute of Chemical Wood Technology, Pozna University of Life Sciences
Department of Plant Physiology, Pozna University of Life Sciences
Abstract: Changes in wood basic chemical composition in Salix viminalis in a model experiment. The study
analysed changes in the content of basic wood constituents of willows (S. viminalis) cultivated hydroponically
with additives of calcium and magnesium as well as selected chemical elements. After a short period of
vegetation, changes in the content of structural components in the wood of willow seedlings were observed.
Keywords: wap , magnez, hodowla hydroponiczna, metale ci kie, celuloza, lignina,
INTRODUCTION
From among 400 species of willows practical use has only 40. At present moment they
are wide use, because an important part of investigation in range of chemistry and
environmental protection became of searching a new plants characterized ability of heavy
metals accumulation in their tissue at high concentration, quick increase of biomass
(Szczukowski S. et al. 1997, Waliszewska and Pr dzy ski 2005, Smaliukas et al. 2007), what
can be used like an energetic material as well as in wood industry (Szczukowski S. et al.
1998, Mirck et al. 2005). What more it is used like an indicator of pollution (Mertens et al.
2004) and like a buffer zones can limit a superficial raftings from field to waste waters
preventing their eutrophication or like a protective willow zone round roads and highways
limited the air pollution and protect field before contamination (Fali ski, 1990). In recent
years, application of the Salix genus has been expanded considerably. Willow effectiveness in
the reclamation of degraded industrial land (Wróblewska et al., 2004) as well as in sewage
treatment (Waliszewska et al. 1999, 2004) is well recognised. Bush varieties of willow, in
particular Salix viminalis, employed in environmental protection are known for their ease of
adaptation to new environmental conditions (Hermle et al., 2006). The willows root system is
capable to taking not only nutritious substances but also can bond of harmful substances, in
this the heavy metals contained in sewages, the settlings as well as in the soil. Heavy metals
presented in natural environment are essential for plants but at higher concentration are toxic,
like cooper (Cu), zinc (Zn), nickel (Ni) (Lee et al. 2004).
Contamination by heavy metals in the natural environment is a major problem for
human health, crop cultivation and quality of environment. What more behavior of heavy
metals is various in contaminated soil (Mleczek et al. 2009) and their affected the uptake by
plant are controlled by soil pH value, redox condition, organic matter (Lee et al. 2004), low
molecular weight organic acids speciation of metals (Dai et al 2004) and probably by the
presented in environment amount of macroelements, first of all calcium and magnesium ratio
(Ca/Mg).
Different species of willows growing in different conditions show an essential
differences in chemical composition of wood, like contents of cellulose, holocellulose and
lignin, as well as in accumulation of heavy metals. (Waliszewska and Pr dzy ski 2001).
395
Therefore essential is to study how above-mentioned factors influence on chemical
parameters of wood.
The aim of presented study was the qualification of changes in structure and chemical
composition of willows seedlings exposed on cadmium, cooper, lead and zinc in dependence
of Ca/Mg ratio.
MATERIALS AND METHOD
One year old Salix viminalis cuttings came from a 2-year old rootstock harvested in
the end of November and stored in moisture box at 5 ºC. Before experiment the standardized
stocks (20 cm of length and similar diameter: diameter of shoots – 6-8 mm, diameter of pith –
3.8-4.0 mm) were incubated for 10 days for rooting in 50% concentration of Knop medium
(10 cm3 of 10% Ca(NO3)2, 2.5 cm3 of 10% KNO3, 1.2 cm3 of 10% KCl, 10 cm3 of 2.5%
KH2PO4, 5 cm3 of 5% MgSO4 and 0.25 cm3 of 0,25% FeCl3 in 1 dm3 of acidified water at
pH=3.94). After that cuttings were put individually into hydroponic pots and stabilized by the
ultra pure river sand. Experiment was conducted 21 days and the reference systems was
combination without heavy metals in Knops medium. Four solution with different Ca/Mg
ratio were used as follows: 20:1, 4:1, 1:1/4 and 1:10. The each plant was incubated in 0.5 dm3
of 0.1 mM solution of each of tested 4 heavy metals (control) and in four experimental
combinations where one of metals was at 0.5 mM concentration while other accompanied at
0.1 mM for example: Cd0.5, Cu0.5, Pb0.5, Zn0.5 (Table 1). Solution of individual heavy metals
(Cd2+, Cu2+, Pb2+, Zn2+) was prepared on the base of analytical grade nitrates (V) dissolved in
de-ionized water (Milli-Q) acidified to 0.08% nitric acid content (Ultrapure).
Table 1. Scheme of different sets of the heavy metals concentrations (mM) in the experiment
Ca/Mg ratios
Cd0.5
0.5
0.1
0.1
0.1
Cu0.5
0.1
0.5
0.1
0.1
Pb0.5
0.1
0.1
0.5
0.1
Zn0.5
0.1
0.1
0.1
0.5
The experiment was performed in a controlled climate chamber equipped with
fluorescent lamp (MASTER TL-D Secura 58W/830 1SL) providing a photon (radiation) flux of
220 E sec-1 m-2 ( mol sec-1 m-2) in the top of the plant for 16 hours of 20±1°C and humidity
of 81-84%. Loss of water was compensated by pure water. The growth medium was not
replaced during experiment with metals and no bactericide was used.
Samples of willow stems used for the determination of chemical composition were
seasoned in an air-conditioned facility until they reached air-dry state. Once they reached the
required moisture content, they were comminuted together with bark using a laboratory mill
Pulverisette 15 of Fritsch Company and an analytic fraction of 0.5-1.0 mm was separated. The
material for cellulose and lignin assays was deprived of extractive substances. Investigations
of the chemical composition were conducted according to the PN 92/P-50092 standard.
396
RESULTS
Table 2. Content of selected chemical composition of Salix in relation to Ca/Mg ratio and heavy metals amount
in solutions
Kind of metal
0
Cellulose
[%]
41.06
Cd0.5
Cu0.5
Pb0.5
Zn0.5
41.50
41.14
43.54
43.11
Cd0.5
Cu0.5
Pb0.5
Zn0.5
45.72
44.11
39.75
43.92
Cd0.5
Cu0.5
Pb0.5
Zn0.5
44.85
43.78
44.88
44.14
Cd0.5
Cu0.5
Pb0.5
Zn0.5
43.51
46.81
43.78
44.93
Lignin
Extractable
[%]
substances [%]
23.26
3.72
4:1 Ca/Mg ratio
24.51
3.51
23.40
2.39
24.46
3.00
24.40
4.09
20:1 Ca/Mg ratio
26.85
2.87
23.72
6.39
23.32
4.42
22.49
4.15
1:1/4 Ca/Mg ratio
22.76
3.65
22.61
3.63
23.26
3.95
23.53
4.17
1:10 Ca/Mg ratio
22.89
2.61
23.52
4.78
23.10
3.03
23.11
3.96
The analysis of the cellulose content in willow seedlings incubated in individual
systems of different Ca/Mg ratios revealed variability of its content depending on the
presence of the metal which occurred at the concentration of 0.5 mM (Table 2).
With regard to individual metals and taking into consideration initial cellulose contents in
seedling, these relations were as follows:
Cd0.5: 20:1 > 1:1/4 > 1:10 > 4:1,
Cu0.5: 1:10 > 20:1 > 1:1/4 > 4:1,
Pb0.5: 1:1/4 > 1:10 > 4:1 > 20:1,
Zn0.5: 1:10 > 1:1/4 > 20:1 > 4:1.
The greatest changes in the cellulose content were determined in plants incubated in
combinations: Cu0.5 (1:10 Ca/Mg) and it was 5.75%. A drop in cellulose content was observed
only for seedlings incubated in the Pb0.5 (20:1 Ca/Mg) combination. It is difficult, on the basis
of the obtained research results, to point unequivocally to simple correlations between the
Ca/Mg ratio and the direction of changes in the cellulose content. Series of Ca/Mg
relationships for individual metals with regard to changes in cellulose content fail to indicate
that the Ca/Mg ratio influenced the amount of this biopolymer in any significant way.
Nevertheless, differences between cellulose content and the metal present in the solution
appear to point to a greater role of the ions of heavy metals found in the solution than that of
both macroelements, i.e. Ca and Mg.
397
The higher the content of cellulose and the lower that of lignin, the greater is the
possibility of utilisation of wood as raw material. That is why, the examined seedlings were
also subjected to analysis for lignin content and the obtained results are presented in Table 2.
Taking into consideration the concentration of the incrusting substance before the beginning
of the experiment, changes in its quantities in incubated plants in the presence of individual
metals can be shown in the form of declining series:
Cd0.5: 20:1 > 4:1 > 1:10 > 1:1/4,
Cu0.5: 20:1 > 1:10 > 4:1> 1:1/4,
Pb0.5: 4:1 > 20:1 > 1:1/4 > 1:10,
Zn0.5: 4:1 > 1:1/4 > 1:10 > 20:1.
Similarly to the case with cellulose, the obtained results indicate variations in lignin
content depending on the metal occurring at the concentration of 0.5 mM. From practical
point of view, the most important are drops in lignin concentrations which were the biggest in
plants incubated in combinations: Zn0.5 (20:1 Ca/Mg) and Cu0.5 (1:1/4 Ca/Mg) and which
amounted to: 0.77% and 0.65%, respectively. However, such changes in lignin content in
seedling cannot be considered as significant.
Bearing in mind the earlier results regarding cellulose, it should be said that plants in
which the greatest changes in cellulose content took place were characterised by changes in
lignin quantities, from 0.4% to 0.5%. This indicates possibility of selecting those
combinations with the aim to explain changes in cellulose and lignin contents in incubated
willow shoots.
The analysis of the extractive substances content revealed their considerable changes
in the incubated shoots depending on the Ca/Mg ratio in treatments containing different heavy
metals. Changes in the content of extracted substances were from 2.39% to 6.39%, Changes
in the content of extractive substances ranged from 2.38% to 6.39% which can indicate
dynamic physiological processes taking place during the experiment, and can be described
using the following dependencies:
Cd0.5: 1:1/4 > 4:1 > 20:1 > 1:10,
Cu0.5: 20:1 > 1:10 > 1:1/4 > 4:1,
Pb0.5: 20:1 > 1:1/4 > 1:10 > 4:1,
Zn0.5: 1:1/4 > 20:1 > 4:1 > 1:10.
The highest increase in the amount of extracted substances was found in the case of
seedlings incubated in combinations Cu0.5 (Ca/Mg 20:1) and Cu0.5 (1:10 Ca/Mg) whose
quantities amounted to: 6.39 % and 4.78%, respectively (Table 2). On the other hand, the
greatest drops were observed in combinations: Cu0.5 (Ca/Mg 4:1) and Cd0.5 (Ca/Mg 1:10)
where the respective quantities were: 2.39% and 2.61 %.
The reported changes in the wood chemical composition of willow (Salix viminalis)
seedlings incubated in a model experiment could be attributed to the action of heavy metals
present in the medium. However, no clear correlation was found between the varying Ca/Mg
ratio and supplementation with individual chemical elements and changes in wood basic
constituents. Depending on the Ca/Mg coefficient, the presence of heavy metals can either
increase or decrease quantities of substances soluble in organic solvents but further special
model investigations are required to confirm this hypothesis.
Acknowledgements
The experimental part of this study was supported by the Ministry of Science and Higher
Education (State Committee for Scientific Research KBN), Grant No. N N310 3218 33.
398
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LAVELLE P., 2004 : Influence of heavy metals on C and N mineralization and microbial
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perspective for biofuel production, evaluation of their dendrometric characteristics and
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9. SZCZUKOWSKI S., TWORKOWSKI J., KWIATKOWSKI J., 1998: Mo liwo ci
wykorzystania biomasy Salix sp. pozyskanej z gruntów ornych jako ekologicznego paliwa
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10. WALISZEWSKA B., PODOBI SKI A., BOBKIEWICZ K., 1999: Sk ad chemiczny
wierzb i redukcja metali ci kich w hydrobotanicznych oczyszczalniach wód. Mat. Konf.
Nauk. WTD SGGW, W-wa, s. 59-65, tab. 5, ryc. 5, poz. lit. 7.
11. WALISZEWSKA B., PR DZY SKI W. (2001): Podstawowy sk ad chemiczny i stopie
polimeryzacji celulozy w jednorocznych i wieloletnich wierzbach krzewiastych rosn cych
przy autostradzie A-2. Mat. IV Krajowe Sympozjum pt. „Reakcje biologiczne drzew na
zanieczyszczenia przemys owe”, ss.10, tab. 2, ryc. 3, poz. lit. 27.
12. WALISZEWSKA B., PR DZY SKI W., ZBOROWSKA M., PEREK T., 2004:
Chemical composition and heavy metals content in willows growing in hydrobotanic
waster treatment plants. In.: Selected Processes at the Wood Processing. (Eds. V.
Velkova, A. Geffert, F. Kacik) Bobrownik 2004.
13. WALISZEWSKA B., PR DZY SKI W., 2005: Chemical composition and heavy metals
content in willow trees (Salix caprea L.), Ann. Warsaw Agricult. Univ.- SGGW, Forestry
and Wood Technology, No 56.
14. WRÓBLEWSKA H., WALISZEWSKA B., PR DZY SKI W., CZAJKA M.,
MA KOWIAK K., 2004: Investigations of Salix purpurea L. plantation on soils supplied
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399
Streszczenie: Zmiany w podstawowym skáadzie chemicznym drewna sadzonek Salix viminalis
w modelowym doĞwiadczeniu. W pracy zbadano zmiany w zawarto ci podstawowych
sk adników drewna wierzby S. viminals pod wp ywem hydroponicznej uprawy z dodatkiem
wapnia i magnezu oraz wybranych pierwiastków. Po krótkim okresie wegetacji
zaobserwowano zmiany zawarto ci sk adników strukturalnych w drewnie sadzonek
wierzbowych.
Bogus awa Waliszewska, W odzimierz Pr dzy ski, Agnieszka Spek-D wiga a
Institute of Chemical Wood Technology,
Ul. Wojska Polskiego 28
60-637 Pozna
e-mail : [email protected]
Tamara Chadzinikolau
Department of Plant Physiology,
60-637 Pozna
Annals of Warsaw Uniwersity of Life Sciences – SGGW
Changes in the degree of cellulose polymerisation of Salix viminalis willow
seedlings after supplementation with Cu and Pb
BOGUS AWA WALISZEWSKA1, W ODZIMIERZ PR DZY SKI1, MONIKA
KOZ OWSKA2, RENATA WOJECH1
1
2
Department of Plant Physiology, Pozna University of Life Sciences
Abstract: Changes in the degree of cellulose polymerisation of Salix viminalis willow seedlings after
supplementation with Cu and Pb. The study examined the degree of polymerisation and polydispersity of
cellulose of willow seedlings in a hydroponic cultivation supplemented with copper and lead. Differences were
demonstrated in the cellulose chain lengths as well as in the content of individual fractions of molecular weights
when the medium was supplemented with copper and lead.
Keywords: cellulose, degree of polymerization, hydroponic cultivation, heavy metals
INTRODUCTION
Willow is a plant which is extremely well adapting to the environment polluted with
heavy metals. According investigations conducted by Mocek (1996) for several cultivars of
willow growing near the copper plant in Legnica the highest content of heavy metals was
found in leafs and roots. Rods being utilitarian parts of the plant contained the lowest amount
of heavy metals. Despite of the high amount of the elements in the plant there was not
observed slowing down of the growth and development of bushes. It proves high adaptation
ability of willows.
The contamination of the natural environment with heavy metals may cause changes
in the chemical composition of wood. The investigations performed for willows growing in a
plantation near the A-2 road (Brzozowska and Pr dzy ski 1995) showed the distinct decrease
of cellulose content from 51% in six years old rods to 37% in rods sampled in the first year
after planting. There was also observed decrease of lignin of 3% as well as insignificant
increase of extractive substances.
Values that characterise cellulose structure as a polymer include the degree of
polymerisation and its polydispersity. Knowledge of these values is necessary to assess the
strength of cellulose fibre as well as the entire timber material as biopolymer. Reduced degree
of polymerisation results in deterioration of timber properties (Prosi ski 1984).
MATERIALS AND METHOD
One year old Salix viminalis cuttings came from a 2-year old rootstock harvested in the end of
November and stored in moisture box at 5 ºC. Before experiment the standardized stocks (20
cm of length and similar diameter: diameter of shoots – 6-8 mm, diameter of pith – 3.8-4.0
mm) were incubated for 10 days for rooting in 50% concentration of Knop medium (10 cm3
of 10% Ca(NO3)2, 2.5 cm3 of 10% KNO3, 1.2 cm3 of 10% KCl, 10 cm3 of 2.5% KH2PO4, 5
cm3 of 5% MgSO4 and 0.25 cm3 of 0,25% FeCl3 in 1 dm3 of acidified water at pH=3.94).
After that cuttings were put individually into hydroponic pots and stabilized by the ultra pure
401
river sand. Experiment was conducted 21 days and the reference systems was combination
without heavy metals in Knops medium. Two solution with different Ca/Mg ratio were used
as follows: 20:1 and 1:10. The each plant was incubated in 0.5 dm3 of 0.5 mM solution of
each of tested 2 heavy metals: Cu and Pb. Solution of individual heavy metals (Cu2+, Pb2+)
was prepared on the base of analytical grade nitrates (V) dissolved in de-ionized water (MilliQ) acidified to 0.08% nitric acid content (Ultrapure).
The experiment was performed in a controlled climate chamber equipped with fluorescent
lamp (MASTER TL-D Secura 58W/830 1SL) providing a photon (radiation) flux of 220 E sec-1
m-2 ( mol sec-1 m-2) in the top of the plant for 16 hours of 20±1°C and humidity of 81-84%.
Loss of water was compensated by pure water. The growth medium was not replaced during
experiment with metals and no bactericide was used.
Analysis of molecular weights, degree of polymerization and polydispersity of cellulose were
performed by gel permeation chromatography (GPC/SEC). GPS System consist of HP 1050
Hewlet Packard liquid chromatographer equipped with differential refractometric detector HP
1047A, manual injector (Model 7125 - Rheodyne Inc.) and column set: 3x PLgel Mixed A,
20μm + guard (Polymer Laboratories Ltd.). Chromatographic parameters were: solvent DMAC/0.5% LiCl, flow rate - 1.0 ml min-1, column set - N`= 10158 (plates/metr), Rs=1.65,
concentration - 0.05%, injection value - 100 μl, temperature - 80 ºC and paek start/end 17.60/26.92. Calibration was performed using barrow polystyrene standards. Values of
molecular weights were calculated using universal calibration methods. Parameters K and a
(Mark-Houwink equation) were as follows: cellulose: K=2.78 10-5 [dL g-1] and a=0.957 and
polystyrene standards: K=17.35 10-5 [dL g-1] and a=0.642.
RESULTS
Initial investigations were carried out at the Institute of Wood Technology and
Department of Plant Physiology of the Pozna University of Life Sciences regarding the
impact of the addition of some heavy metals on changes in the wood of Salix viminalis during
hydroponic cultivation. On the basis of the obtained results, two metals - copper and lead –
were selected for further experiments with the aim to examine the influence of their addition
to the medium on the quality of cellulose in the timber of seedlings. Bearing in mind the fact
that changes in cellulose quantities occurred only in specific combinations, analyses of the
most interesting of them were performed with the aim to assess the degree of cellulose
polymerisation and polydispersity and to determine the distribution of the molecular weight
and mean molecular weights. The following three experimental combinations were analysed:
1. Control combination 0, in order to determine initial parameters (samples subjected to
no treatment),
2. Addition of Pb0.5 (at Ca/Mg 20:1) - due to the highest cellulose content,
3. Addition of Cu0.5 (at Ca/Mg 1:10) - due to the lowest cellulose content.
402
Table 1.Characteristic of cellulose for Salix cuttings incubated in selected combinations
Parameter
Mp
Mn
Mv
Mw
DPw
PDI (Mw/Mn)
low
medium
high
Unit
g mol-1
-
M<20000
20000<M<200000
M>200000
Combinations
Cu0.5
Pb0.5
0 (control)
(Ca/Mg 20:1)
(Ca/Mg 1:10)
Molecular weights averages
71796
67464
64703
40566
34813
35836
184720
176052
144771
190307
181481
148840
1180
1120
920
4.7
5.2
4.2
Content of fractions, M [%]
13
16
15
60
58
63
27
26
22
Mp – amount of highly polymerised molecules; Mn - number-average molecular weight; Mv – viscosity-average
molecular weight; Mw - weight-average molecular weight; DPw - degree of polymerization, PDI – polydispersity;
The obtained results collated in Table 1 show a decline in the degree of cellulose
polymerisation. The highest drop in the degree of cellulose polymerisation was observed in
samples in which both the highest and lowest cellulose contents were determined. In the
sample with the addition of Pb0.5 (Ca/Mg 20:1), in which the lowest cellulose content of
39.75% was recorded (Waliszewska et al., 2010), the degree of its polymerisation amounted
to 920, while in the reference sample DPw, it amounted to 1120, which means that it was close
to 1200, i.e. the value characteristic for the cellulose from wood obtained with the assistance
of Seifert’s method. In the case of samples incubated in Cu0.5 (Ca/Mg 1:10) solution, the
degree of cellulose polymerisation dropped to 1120, at the highest degree of PDI
polydispersity amounting to 5.2. On the other hand, the lowest degree of cellulose
polydispersity of 4.2 was determined in samples subjected to the action of Pb0.5 (Ca/Mg 20:1)
solution which was also accompanied by the lowest degree of cellulose polymerisation
amounting to 920. In willow samples incubated in both Cu0.5 (Ca/Mg 1:10) and Pb0.5 (Ca/Mg
20:1) solutions, the percentage proportion of individual fractions of molecular weights, in
relation to the control sample, showed an increase in the proportion of the fraction with
molecular weight of M<20 000 and a decrease in the proportion of the M>200 000 fraction. In
the case of the sample treated with the Pb0.5 (Ca/Mg 20:1) solution, the proportion of the
fraction of the highest molecular weight amounted to 22%, while in the control sample –
27%.
It is difficult to state unequivocally what the probable cause of shortening of cellulose
chains was. It is known that hemicelluloses and pectins are characterised by a greater capacity
to bind heavy metal ions than cellulose and lignin. Cellulose molecules, forming characteristic
chains, are arranged in a regular manner giving cell walls a precisely definite, orderly
structure. Between cellulose chains, there are free spaces filled with water and pectins and,
hence, the observed considerable ease of accumulation of metal ions in these spaces. It is the
opinion of the authors that the presence of heavy metal ions in these places, combined with
acid hydrolysis triggered off by the action of acid metal salts, can be the main causes of
shortening of cellulose chains. At the same time, variations in the degree of chain shortening,
depending on the type of the metal found in the medium, indicate a slightly different influence
of each of them on changes in the plant structure.
403
Acknowledgements
The experimental part of this study was supported by the Ministry of Science and Higher
Education (State Committee for Scientific Research KBN), Grant No. N N310 3218 33.
REFERENCES
1. BRZOZOWSKA K., PR DZY SKI W., 1995: Krzewy wierzbowe jako indykatory
zanieczyszcze rodowiska metalami ci kimi. Roczniki AR CCLXXIX Chem. Techn.
Drewna 27/28.
2. MOCEK A., 1996: Odporno krzewostanów wierzby na ska enia metalami ci kimi i
siark . Mat. Konf. „Kompleksowe wykorzystanie wierzb krzewiastych z krajowych
plantacji”. Pozna -Zielonka.
3. PROSI SKI S., 1984: Chemia drewna. PWRiL Warszawa.
4. WALISZEWSKA B., PR DZY SKI W., CHADZINIKOLAU T., SPEK-D WIGA A
A., 2010: Changes in wood basic chemical composition in Salix viminalis in a model
experiment. W tym e: Ann. WULS-SGGW, For and Wood Technol. 71, 2010.
Streszczenie: Zmiany stopnia polimeryzacji celulozy sadzonek wierzbowych Salix viminalis w
wyniku dodatku Cu i Pb. W pracy zbadano zmiany stopnia polimeryzacji i polidyspersyjno ci
celulozy sadzonek wierzbowych w uprawie hydroponicznej z dodatkiem miedzi i o owiu.
Wykazano ró nice w d ugo ci a cuchów celulozowych oraz zawarto ci poszczególnych
frakcji mas cz steczkowych przy dodatku miedzi i o owiu do po ywki.
Bogus awa Waliszewska, W odzimierz Pr dzy ski, Renata Wojech
60-637 Pozna
Monika Koz owska
Department of Plant Physiology,
60-637 Pozna
(Ann. WULS - SGGW, For. and Wood Technol. 72, 2010)
Particle size dependent properties of three-layer particleboards with the
core layer made from willow (Salix viminalis)
KRZYSZTOF WARMBIER1), ARNOLD WILCZY SKI1), LESZEK DANECKI2)
1)
2)
Institute of Technology, Kazimierz Wielki University in Bydgoszcz
Research and Development Centre for Wood-Based Panels Industry in Czarna Woda
Abstract: Particle size dependent properties of three-layer particleboards with the core layer made from willow
(Salix viminalis). Three-layer experimental particleboards were prepared using basket willow (Salix viminalis)
particles for the core layer and industrial pine particles for the face layers. The effect of willow particle size (12.4, 2.4-4, and >4 mm) on modulus of elasticity (MOE), modulus of rupture (MOR), internal bond (IB), and
thickness swelling (TS) was investigated. The medium particles (2.4-4 mm) provided better particleboard
properties than the small (1-2.4 mm) and large (>4 mm) ones. For comparison, the properties of particleboards
with the core layer made from pine particles of the same sizes were studied. Both MOE and MOR of
particleboards with the core layer from willow and pine particles differed slightly, whereas IB of particleboards
with the willow core layer was smaller and TS was greater than those with the pine core layer.
Keywords: particleboard, willow, particle size, mechanical properties, physical property
INTRODUCTION
Particleboard is one of the most important wood composites. Systematic growth of
particleboard industry in many countries, including Poland, and limited wood resources make
it necessary to use other alternative lignocellulosic materials in particleboard manufacturing.
These alternative materials are usually weaker material than wood, therefore it is
recommended to use them for production the core layer of three-layer particleboards. In
recent years many investigations have been made on partial or total replacement of wood in
the core layer of the particleboards with waste lignocellulosic agricultural products, such as
kenaf stalks (Grigoriou et al. 2000, Kalaycioglu and Nemli 2006), castor stalks (Grigoriou et
al. 2001), oat hulls (Czarnecki et al. 2001), vine prunings (Ntalos and Grigoriou 2002), kiwi
prunings (Nemli et al. 2003), cotton stalks (Guler and Ozen 2004), rape straw (Fr ckowiak
2004, 2007, Fr ckowiak et al. 2008), cotton carpel (Alma et al. 2005), sunflower stalks (Guler
et al. 2006), needle litter (Nemli and Aydin 2007), eggplant stalks (Guntenkin and Karakus
2008), peanut hulls (Guler et al. 2008), evening primrose straw (Czarnecki et al. 2009,
Dukarska et al. 2010) and grass plant (Kurowska and Borysiuk 2009).
Other raw material to be used for production the core layer of particleboards can be
fast growing bushes. Such a bush being cultivated in Poland for energetic purposes is basket
willow. Its usefulness for production of particleboards was proved by the studies of
Fr ckowiak (2007) and Fr ckowiak et al. (2008). Considering the needs of the Polish
particleboard industry, it is recommended to continue investigations into the properties of
particleboard made using basket willow particles.
The main aim of this study was to assess the effect of particle size in the core layer on
some properties of three-layer experimental particleboard with the core layer made from
basket willow.
405
The raw material for the core layer was obtained from a basket willow plantation in
Mie cisko (Poland). Three-year willow stems were stored for air-drying to a moisture content
of about 12%, then chipped in a hammer-mill and screened by an analytical sieve shaker
using the sieves of 5, 8 and 18 mesh to obtain three particle sizes: 1-2.4, 2.4-4 and >4 mm.
The raw material for the face layers was industrial fine particles made from pine wood,
supplied by Pfleiderer Prospan Wieruszów (Poland). All the particles were dried to achieve a
moisture content of less than 3%. Urea formaldehyde resin was used as a binder and no
hydrophobic agent was added. The resin content was 8 and 10% for the core and face layers,
respectively. The ratio of the thickness of the face layers to the thickness of the board was 0.4,
the target board density was 0.70 g/cm3 and the thickness was 16 mm. The pressing
conditions were: temperature of 180 oC, maximum pressure of 2.5 MPa and pressing time of
4 min. Four experimental boards were manufactured for each size of particles in the core
layer.
For comparison, three-layer particleboards with the core layer made from industrial
pine particles supplied by Pfleiderer Prospan Wieruszów were prepared. Particle sizes, board
construction and pressing conditions were the same as for the particleboard with the willow
core layer.
Prior to testing all the boards were stored in controlled conditions (50% relative
humidity and 20 oC) for two weeks. The following properties of produced particleboards were
determined according to EN standards: modulus of elasticity (MOE) and modulus of rupture
(MOR) according to EN 310: 1994, internal bond (IB) according to EN 319: 1999, and
thickness swelling (TS) after 24 h according to EN 317: 1999. Test specimens for IB and TS
were prepared from the specimens that were formerly tested for MOE and MOR. Twenty
replicates were run for each test.
RESULTS
Results of the tests are given in Figs 1-4. Error bars represented ±standard deviation
based on twenty specimens. Mechanical properties in bending of tested particleboards (Figs 1
and 2) with the core layer made from particles of size of 2.4-4 mm are slightly better than
those with the core layer made from particles of sizes of 1-2.4 and >4 mm. This relation
concerns both particleboards with the willow and pine core layer. MOE of particleboards with
2.4-4 mm particles is on the average by 4.5% and 5.9% higher than MOE of particleboards
with 1-2.4 and >4 mm particles, respectively. Similarly, MOR of particleboards with 2.4-4
mm particles is on the average by 3.1% and 7.6% higher than MOR of particleboards with 12.4 and >4 mm particles, respectively. IB of particleboards (Fig. 3) with 2.4-4 mm particles in
the core layer is markedly, on the average by 22.5% and 16.4%, higher than that of
particleboards with 1-2.4 and >4 mm particles, respectively. TS of particleboards (Fig. 4) with
the core layer from willow particles of 1-2.4 and 2.4-4 mm is almost the same, and is on
average by 15.0% higher for particleboards with willow particles of >4 mm. TS of
particleboards with the core layer from pine particles increases gradually when particle size
increases from 1-2.4 to >4 mm, and for particleboards with >4 mm particles it is by 17.0%
higher than that for particleboards with 1-2.4 mm particles.
Mechanical properties of particleboards with the core layer from willow are worse
than those of particleboards with the core layer from pine (Figs 1-3). MOE is on the average
by 5.6%, MOR by 3.3% and IB by 15.0% smaller. The substitution of willow particles for
pine ones in the core layer therefore results in relative small reduction in particleboard
mechanical properties, especially in reduction in MOE and MOR. One should note that
mechanical properties of particleboard with the core layer from willow particles of size of
406
Fig. 1. Modulus of elasticity of particleboards with
the core layer made from particles of different sizes
Fig. 2. Modulus of rupture of particleboards with
the core layer made from particles of different sizes
Fig. 3. Internal bond of particleboards with the
core layer made from particles of different sizes
Fig.4. Thickness swelling after 24 h of
particleboards with the core layer made from
particles of different sizes
407
2.4-4 mm meet the requirements of the EN 312 standard for the particleboard of type P2
(MOE 1600 MPa, MOR 13 MPa, IB 0.35 MPa). TS of particleboards with the core
layer from willow is higher, on the average by 23.8%, than that of particleboards with this
layer from pine.
CONCLUSIONS
Properties of three-layer particleboards with the core layer made from basket willow
particles depend on the size of particles. The particles of 2.4-4 mm provide better properties
(MOE, MOR, IB and TS) than the particles of 1-2.4 and > 4 mm. Compared with three-layer
particleboards with the core layer made from industrial pine particles, the properties of
particleboards with this layer from willow particles are slightly smaller, but mechanical
properties of particleboards with the core layer from willow particles of 2.4-4 mm meet the
requirements of the EN 312 standard for the particleboard of type P2.
REFERENCES
1. ALMA M.H., KALAYCIOGLU H., BEKTAS I., TUTUS A., 2005: Properties of
cotton carpel-based particleboards. Industrial Crops and Products 22: 141-149.
2. CZARNECKI R., DUKARSKA D.,
CKA J., 2009: The possibility of using
evening primrose waste as a substitute for wood particles of the center layer in the
process of producing particleboards glued with PMDI resin. Annals of Warsaw
University of Life Sciences-SGGW, Forestry and Wood Technology 68: 92-96.
3. CZARNECKI R., DZIURKA D., MIRSKI R., 2001: The possibility of using oat hulls
as a substitute for wood particles for particleboard manufacturing (in Polish).
Przemys Drzewny 3: 21-23.
4. DUKARSKA D.,
CKA J., CZARNECKI R., 2010: Properties of boards
manufactured from evening primrose straw particles depending on the amount and
type of binding agent. Electronic Journal of Polish Agriculture Universities 13 (1) #8.
5. FR CKOWIAK I., 2004: From studies on using rape straw for particleboard
production (in Polish). DREWNO-WOOD 47, 171: 31-47.
6. FR CKOWIAK I., 2007: From studies on using alternative lignocellulosic raw
materials for particleboard production (in Polish). Technologia Drewna - Wczoraj,
Dzi , Jutro, Pozna : 285-294.
7. FR CKOWIAK I., FUCZEK D., KOWALUK G., 2008: Impact of different
lignocellulosic materials used in core of particleboard on modulus of elasticity and
bending strength. DREWNO-WOOD 51, 180: 5-13.
8. GRIGORIOU A.H., NTALOS G.A., 2001: The potential use of Ricinus Communis L.
(Castor) stalks as a lignocellulosic resource for particleboards. Industrial Crops and
Products 13: 209-218.
9. GRIGORIOU A., PASSIALIS C., VOULGARIDIS E., 2000: Experimental
particleboards from Kenaf plantations grown in Greece. Holz als Roh-und Werkstoff
58:309-314.
10. GULER C., BEKTAS I., KALAYCIOGLU H., 2006: The experimental particleboard
manufacture from sunflower stalks (Helianthus annuus L.) and Calabrian pine (Pinus
brutia Ten.). Forest Products Journal 56, 4: 56-60.
11. GULER C., OZEN R., 2004: Some properties of particleboards made from cotton
stalks (Gossypium hirsitum L.). Holz als Roh-und Werkstoff 62: 40-43.
408
12. GULER C., COPUR Y., TASCIOGLU C., 2008: The manufacture of particleboards
using mixture of peanut hull (Arachis hypoqaea L.) and European Black pine (Pinus
nigra ARNOLD) wood chips. Bioresource Technology 99: 2893-2897.
13. GUNTEKIN E., KARAKUS B., 2008: Feasibility of using eggplant (Solanum
melongena) stalks in the production of experimental particleboard. Industrial Crops
and Products 27: 354-358.
14. KALAYCIOGLU H., NEMLI G., 2006: Producing composite particleboard from
kenaf (Hibiscus cannabinus L.) stalks. Industrial Crops and Products 24: 177-180.
15. KUROWSKA A., BORYSIUK P., 2009: Particleboards with grass plant additive.
Annals of Warsaw University of Life Sciences-SGGW, Forestry and Wood
Technology 68: 463-466.
16. NEMLI G., AYDIN A., 2007: Evaluation of the physical and mechanical properties of
particleboard made from the needle litter of Pinus pinaster Ait. Industrial Crops and
Products 26: 252-258.
17. NEMLI G., KIRCI H., SERDAR B., AY N., 2003: Suitability of kiwi (Actinidia
sinensis Planch.) prunings for particleboard manufacturing. Industrial Crops and
Products 17: 39-46.
18. NTALOS G.A., GRIGORIOU A.H., 2002: Characterization and utilization of vine
prunings as a wood substitute for particleboard production. Industrial Crops and
Products 16: 59-68.
Streszczenie: WáaĞciwoĞci trzywarstwowych páyt wiórowych z warstwą wewnĊtrzną
wykonaną z wiórów wierzby Salix viminalis. Wpáyw wielkoĞci wiórów. Wykonano
trzywarstwowe p yty wiórowe stosuj c wióry wierzby wiciowej (Salix viminalis) na warstw
wewn trzn i przemys owe wióry sosnowe na warstwy zewn trzne. Badano wp yw wielko ci
wiórów wierzbowych (1-2.4, 2.4-4 i > 4 mm) na modu spr ysto ci (MOE), wytrzyma o na
zginanie (MOR), wytrzyma o na rozci ganie poprzeczne (IB) i sp cznienie na grubo
(TS). rednie wióry (2.4-4 mm) zapewnia y lepsze w a ciwo ci p yty ni ma e (1-2.4 mm) i
du e (> 4 mm). Dla porównania badano w a ciwo ci p yt z warstw wewn trzn wykonan z
wiórów sosnowych o tych samych wielko ciach. Zarówno MOE, jak i MOR p yt wiórowych
z warstw wewn trzn z wiórów wierzbowych i sosnowych ró ni y si nieznacznie, natomiast
IB p yt z warstw wewn trzn z wierzby by a mniejsza a TS wi ksze ni p yt z warstw
wewn trzn z sosny.
Acknowledgement: This research project has been supported by the Polish Ministry of
Science and Higher Education, grant number N N309 133535.
Krzysztof Warmbier, Arnold Wilczy ski
Institute of Technology,
Kazimierz Wielki University
Chodkiewicza 30 str.
85-064 Bydgoszcz, Poland
Leszek Danecki
Research and Development Centre for Wood-Based Panels Industry in Czarna Woda
Mickiewicza 10 str.
83-262 Czarna Woda, Poland
Ultimate distortion of circular saw
R. WASIELEWSKI
Gdansk University of Technology
Abstract: Ultimate distortion of circular saw. Below paper presents modes and effects of the transverse
distortion of circular saw. Also shown is dependence which determines ultimate distortion of circular saw.
INTRODUCTION
During wood cutting by means of circular saw, due to action of transverse load and
limited stiffness of the saw, it comes to transverse distortion of the saw. Effects of that
distortion depend on characteristics and value of the saw’s distortion [WASIELEWSKI,
OR OWSKI]. In case of slowly changing thrust force it comes to distortions which are direct
effect is lowered cutting precision. It happens however, that saw’s distortion can reach such
values that lead to destruction of the saw and material, what endangers whole cutting system
and the operator.
Analysis of modes and effects of transverse distortion of circular saw enables better
understanding of its behaviour during cutting process, what can lead to increased precision
and safety during cutting by means of circular saw.
MODES AND EFFECTS OF TRANSVERSE DISTORTION OF CIRCULAR SAW
Analysis of modes and effects of transverse distortion of circular saw during slowly
changing loads can show areas of different behaviour of the saw (fig.1). The ultimate
distortion is very characteristic value. The ultimate distortion is its such value by which edge
of the cat material being closer to spindle axis touches body of the saw (fig.1c). The value of
this distortion is considered as ultimate because it separates two different behaviour of saw
during cutting process.
In case of saw’s distortion smaller than ultimate value (f < fg) (fig. 1b) the only
negative effect is decreased cutting precision. In such conditions, body of the saw does not
have contact with cut material. Transverse load of the saw results only from thrust force on
cutting blade and change of that value causes change of the saw’s distortion.
410
b)
a)
c)
f = fg
f > fg
D/2 - a
D/2 - Dt/2
St
d)
fd
F pk
a
s
D
Dt
Fig.1. Distortion of the saw during cutting process, where : a) cutting scheme, b) no distortion,
c) ultimate distortion, d) destructive distortion
In case of distortion bigger than ultimate value (f > fg) (fig. 1d) it may come to
destruction of the saw what is dangerous both for the machine and for the operator. In such
conditions it comes to contact between saw’s body and cut material. Cut material pressing on
the body near the edge of the material being closer to spindle axis with Fpk force causes that
blades create new surface further away by fd value from the surface which is currently
pressing saw’s body. As the effect, this new surface is creating even bigger distortion of the
saw. Saw is acting then as system with positive feedback striving to even bigger distortion
what eventually leads do saw’s destruction. Sample saw destroyed that way is shown in fig.2.
Fig.2. Sample saw destroyed due to
distortion higher then ultimate
This drawing shows visible friction marks caused by pressure of cut material onto saw’s
body. That mark is located away from the blades (as in fig.1d). Due to significant distortion it
came to destruction of the saw resulting from separation of the saw’s part located between
pressing rings and the body.
VALUE OF THE ULTIMATE DISTORTION OF CIRCULAR SAW
Assuming that :
there are no plastic or elastic distortion of cut material,
distortion of the saw along radius is linear,
value of the ultimate distortion fg can be determined by (fig.1) :
411
St s / 2
D/2a
where :
fg
D Dt / 2
St s D Dt 4D / 2 a fg
(1)
(2)
Because of the safety reasons, during cutting process one needs to strive for value of saw’s
distortion f was smaller than ultimate value fg .
f fg
(3)
Saw’s distortion value depends on slowly changing transverse load of the saw Fp and its
static stiffness k, which depends also on geometrical features of the saw
(k =f(D, Dt, s,...)) [WASIELEWSKI]
Fp
f
(4)
k
Taking (4) and (2) into (3) we receive inequality, which secures saw from destruction.
Fp
k
St s D Dt 4D / 2 a (5)
Using dependence (5) in reality is however difficult. It results from the fact that beside
geometrical features describing cutting system, in dependence (5) appears thrust force value
Fp, which is difficult to assess. It results from the fact that thrust force Fp depends on many
factors and also it changes during cutting process.
During analysis of (2) and (4), it can be seen that similar factors of cutting system can
influence value of saw’s distortion f and ultimate value fg. It causes that those values are
interdependent. It means, that in safe system (with high value of ultimate distortion fg) saws
can have high distortion values f, what decreases cutting precision. In case of precise cutting
(small values of saw’s distortion f), value of ultimate distortion fg should have low values,
what causes higher probability of saw’s destruction. Conducted analysis shows dependence
between precision and safety of cutting.
SUMMARY
Awareness of the dependence describing distortion of the circular saw enables proper
selection of cutting process factors in order to increase precision and safety of cutting by
means of circular saw.
REFERENCES
1. [1] R. WASIELEWSKI, K. OR OWSKI, Wybrane przyczyny niedok adno ci
przecinania drewna pi ami, W: Vplyv techniky na kvalitu deleného a obrábaného
dreva / ed. L. Dzurenda / Technická univerzita vo Zvolene Drevárska fakulta. –
Zvolen, (Vedecké štúdie ; 2/2008/B),Tech. univ. vo Zvolene, 2008.
2. [2] R. WASIELEWSKI, Static stiffness of circular saw, Annals of Warsaw University
of Life Sciences - SGGW. Forestry and Wood Technology. - 2009, Nr 69, s. 393-396.
412
Streszczenie: Graniczne odksztaácenie piáy tarczowej. W niniejszym artykule opisano
przyczyny i efekty poprzecznego odkszta cenia pi y tarczowej. Przedstawiono równie
zale no , na podstawie której wyznaczy mo na graniczn warto odkszta cenia pi y
tarczowe.
Losses and raw material yield of wood sawing processes
R. WASIELEWSKI
Abstract: Losses and raw material yield of wood sawing processes. Below paper presents method to determine
absolute and relative material losses as well as material efficiency in wood cutting process.
INTRODUCTION
Basic objective of wood cutting process is to procure the most possible volume of
properly shaped objects from given volume of raw material. In general case, the difference
between volume of raw material and volume of procured objects is material waste. In wood
cutting process, material losses are result of both machining process and manufacturing
process. Losses of machining process are created during machining and are directly connected
to machining process itself [OR OWSKI]. Manufacturing losses are result from cutting
method or preparation for cutting and are only indirectly related to machining process.
Further part of the paper is analysis of only direct losses of cutting process which are
material losses of machining process.
DETERMINATION OF LOSSES AND MATERIAL EFFICIENCY
Independently on location of real thickness of cut element in the range of <Gmin, Gmax>
in relation to assumed thickness from range of <G*min, G*max>, maximum value of the slot R
is always absolute material loss (fig.1).
In theoretical cutting system it is assumed that maximum value of the slot R is equal to
total span of tooth blades St (R=St).
In real system, in general case (fig.1, slot 1), maximum slot value R is a sum of total
tooth blade span St and precision of axial location of the tooth blades in relation to cut
material B.
R
St B
( 1)
In case where changes of axial location of tooth blades in relation to cut material are
slow, what results in surfaces on both sides of the saw are circular (fig.1, slot 2), then
precision of axial position of tooth blades in relation to cut material B is equal to surface
roughness after cutting Rt (B=Rt), and then maximum value of the slot R can be determined
by sum of total tooth blade span St and surface roughness Rt
R
S t Rt
( 2)
414
G* min
G* max
St
B/2
Gmin
Rt2
Rt1
R
Gmax
2
Fig.1. Thickness changes of procured
element and slot size, where :
G*min, G*max – min. i max. values of
assumed thickness,
Gmin, Gmax – min. i max. values of
real thickness,
1
In cutting process, apart from absolute losses, significant are also relative material
losses. Those losses show what part in total material usage is the absolute material loss.
Relative material losses have particular meaning in cutting process, where procured are thin
elements with thickness G comparable to slot size R. In such case, to procure one element,
relative material loss Q in general condition might be determined from :
Q
R
G min R
( 3)
where: Gmin+R – is quantity of material USD to manufacture one element in cutting process.
Apart from relative material losses, in many cases it is easier to use relative material
efficiency. This feature describes what part in total material usage is finished element. To
procure one element, relative material efficiency W in general case can be determined from :
W
Gmin
Gmin R
1 Q
( 4)
In industrial reality, determination of losses and material efficiency is based on
comparison of quantity of finished elements procured from given raw material.
In case when raw material on its whole length L has equal width G and height H, then
very simply one can compare :
number of procured elements from the same width of raw material
or width of raw material to get the same number of finished elements.
However often in industrial reality finished pieces are procured from raw material
whose width and height change along its length.
Sample of such cutting is shown in fig.2.
415
a)
Gc
D
percentage distribution
of dimension D
100 [%]
H
b)
50
D [mm]
0
A
L
W
c)
W
Dmin
Dmax
Gc
Gc'
Gc/2
d)
D
Fig. .2. Material with width and height changing along its length
In presented case, shape of raw material (fig.2a) causes that width of raw material with
height H along length L is changing. The smallest value of material width with height H is
dimension D. In the batch of material which comes to cutter, the smallest dimension D can
change in range of <Dmin, Dmax>. During cutting of big batch of such material it can be
assumed that probability of cutting raw material with size D in range of <Dmin, Dmax> is the
same (linear distribution of dimension D). Percentage distribution of dimension D in batch of
such material is shown in fig. 2b. In case when from such raw material one procures elements
like in fig. 2c, for which total width of Gc is required only W% of elements A can achieve
height H along whole length L. Usage of cutting technology in which to procure the same
elements total width of Gc’ is needed (fig. 2d) causes that quantity of elements A with
dimension H along whole length L will increase by 'W %. That increase of element A
efficiency, for Dmin < Gc < Dmax rusting assumed (linear) distribution of dimension D in
batch of pieces to cut, can be determined from :
'W
'Gc
100
Dmax Dmin
Gc Gc'
100 [%]
Dmax Dmin
(5)
From (5) it results that during procurement of finished elements from raw material as
in fig.2, the material efficiency depends both on necessary total Gc width of procured
elements, and on value of spread of smallest dimension D with full height H.
SUMMARY
A method to determine material losses and efficiency during wood cutting process
depends on objective of the analysis. Knowledge of the dependencies describing material
losses and the material efficiency enables suitable selection of cutting conditions to decrease
416
material losses what significantly influence economical and ecological effects of cutting
process.
REFERENCES
1. K. OR OWSKI, Materia ooszcz dne i dok adne przecinanie drewna pi ami, Politechnika
Gda ska, Monografie 40, Gda sk 2003.
Streszczenie: Straty i wydajnoĞü materiaáowa procesu przecinania drewna. W niniejszym
artykule opisano sposób wyznaczania bezwzgl dnych i wzgl dnych strat materia owych, jak
równie wydajno ci materia owej w procesie przecinania drewna.
Diagnostic usefulness of granulometric analyses of chips distribution while
sawing of wood
R. WASIELEWSKI1, K. OR OWSKI1, L. DZURENDA2
1
Gdansk University of Technology, Poland
2
Department of Woodworking, Faculty of Wood Sciences and Technology, Technical University in Zvolen,
Slovakia
Abstract: Diagnostic usefulness of granulometric analyses of chips distribution while sawing of wood. In this
paper ways of chips transportation and those ways’ effect on chips’ size reduction in wood sawing process are
described. The granulometric distributions of chips obtained during sawing with circular saw blades of the
regular design with the circular saw blade in which gullets are semi-closed have been presented.
Keywords: sawdust, chips, granulometric analysis, wood cutting, circular sawing machine
INTRODUCTION
Chips (sawdust) formed in machining bring out a lot of information about the realised
process. Their analyses may be a source of messages about phenomena which accompany the
machining. In wood cutting shape and size of chips, their chemical and physical properties
depend on many factors as follows: raw material (species, moisture content, wood
temperature [1 Sandak et al.]), a circular saw (geometry, cutting speed, feed per tooth,
position in relation to a workpiece, workpiece height, type of sawing: climb or up-sawing)
and a machine tool (accuracy of workpiece movement in relation to a saw blade). The
presented factors only decide about chips’ shape formed in the cutting zone. Those chips
could have different forms. Furthermore, in specific cutting conditions their dimensions result
from cutting parameters (cut thickness, a overall set and a contact length with the workpiece).
Thus, those chips have the unique character of continuous chips(fig. 1a). Nonetheless, in a
large majority of cases formed chips are rather in character of small measure particles (fig.
1b) [2 Dzurenda et al.].
The path of chip transportation from the cutting zone (a place of its formation) to the
workpiece outside is an additional factor which affects formed chips. It is just a result of the
cutting conditions in the narrow slot in which the circular saw blade relocates. This causes
some difficulties with removal of chips outside of the workpiece, which are accompanied by a
lot of disadvantageous phenomena. They could cause a decrease in quality and accuracy of
sawn surfaces, an increase of the circular saw blade wear, and also in particular cases tools’
destruction, a workpiece damage or even in case of the machine tool its serious break-down.
Hence, the proper transportation of chips from the cutting zone to the workpiece outside is
part and parcel of the cutting process with circular saw blades.
418
a)
b)
Fig. 1. Examples of chip forms formed during wood sawing: a) continuous chips, b) fine chips and sawdust
If chips and sawdust are collected outside of the workpiece it is feasible, on the basis
of their granulometric analysis, to obtain information not only about the sawing process but
also about the way of chips and sawdust transportation from the cutting zone (the place of
chips formation) to the place their collection.
WAYS OF CHIPS’ TRANSPORTATION IN THE CUTTIG PROCESS WITH CIRCULAR
SAW BLADES
In circular saw blades of the regular design, commonly used in the sawmill industry
(fig. 2a), only a part of chips formed in the cutting process is directly conveyed in gullets and
then thrown out the workpiece [3 Wasielewski]. The chips’ residuum remains longer in the
kerf slot being transported on both sides of the saw blade and also between successive teeth.
For that reason only some chips are conveyed outside the workpiece by the saw blade.
Furthermore, a part of chips, which are still present in the slot between the saw blade and the
kerf wall, are eventually thrown out by passive teeth on the top surface of the workpiece.
With the purpose of the chip transport intensification in many circular saw blade designs
additional slots (grooves) of different shape, sometimes equipped with cleaning carbide
knives, are applied.
Another type of the chips’ transportation characterizes circular saw blades in which
gullets are semi-closed (fig. 2b) [4 Wasielewski et al., 5 Wasielewski et al., 6 Wasielewski].
The gullet design in those circular saw blades allows chips to stay in it and reduce
simultaneously the chips’ flow between teeth and on the saw blade. The design of gullets is
characterized by the connection of the tooth with the properly formed carbide cleaning knife.
As a result chips are kept in the gullet and move together in it (fig. 2b). While circular saw
blade teeth leave the slot (kerf) the chips are removed beyond the workpiece. Semi-closed
gullets in circular saw blades have improved cutting conditions of saws.
419
a)
b)
s1
St
s
St
+
-
Fig. 2. Ways of chips transportation during sawing of wood with circular saw blades of the regular design
(commonly used) (a) and circular saw blades with semi-closed gullets (b)
THE EFFECT OF THE SAWDUST TRANSPORTATION WAY ON CHIPS’
DIMENSIONS
Thanks to the modification in chip transportation ways there is, among other things, a
visible change in dimensions of examined sawdust particles and chips. Not only the cutting
process affects chips dimensions but also a way of their transportation whereas in the
meantime the chips might be additionally disintegrated. The examples of granulometric
sawdust distributions are presented in fig. 3 for the case of sawing with the circular saw blade
of the regular design (fig. 2a), and for the modified circular saw blade with semi-closed
gullets (fig. 2b). Other cutting conditions such as a kind of sawed species (pine), a workpiece
height and moisture content (MC ~25%) were the same in those experiments.
In figure 3 there is visible that after sawing process with the circular saw blade in
which gullets are semi-closed a number of obtained bigger chips (2mm and 1 mm mesh size
in sieving) is fairly larger. On the other side, in the cutting with the circular saw blade of the
regular design we obtained a lower number of larger chips and also a larger volume of small
chips of dimension equal to ~0.5 mm (mesh size during sieving). The latter follows from the
phenomenon of disintegration process of the larger chips’ portion during their movement
between the saw blade and a formed kerf wall. They are comminuted to the dimension which
is roughly equal to the side slot dimension. In the case of sawing with the circular saw blade
shown in fig. 2a the side slot dimension was equal just ~0.5 mm ((St–s)/2 | 0.5 mm, where St
is a theoretical kerf value (overall set) and s is a saw blade thickness).
420
Fig. 3. Granulometric distribution of chips and sawdust obtained during sawing of pine with circular saw blades
of the common design of gullets (old saw) and circular saw blades with semi-closed gullets (new saw)
SUMMARY
Size of chips in wood sawing process undergoes a change because of the long way of
their transportation from the place of forming to the workpiece outside (disintegration
phenomenon). The comparison of granulometric chips’ distributions allows us to analyse
ways of sawdust transportations from the cutting zone to the workpiece outside.
REFERENCES
1. J. SANDAK, K. ORLOWSKI, M. NEGRI, Divination from chips: monitoring of the
sawing process with chip geometry analyzes. In: V. Medzinarodna Vedecka Konferencia
Trieskove a Beztrieskove Obrabanie Dreva '06 : zbornik prednášok, Stary Smokovec,
Slovakia, 12–14.10.2006 / eds: L. Dzurenda, A. Banski / Technicka univerzita vo
Zvolene, Drevarska Fakulta, Katedra Obrabania Dreva. - Zvolen : Tech. Univ., 2006. p.
253–258.
2. L. DZURENDA, K.A. ORLOWSKI, M. GRZESKIEWICZ, Effect of thermal
modification of oak wood on sawdust granurality. Drvna Industrija 61 (2): 89–94, 2010.
3. R. WASIELEWSKI, Transportation of chips in the machining zone during cutting wood
with circular saw. Annals of Warsaw University of Life Sciences. Forestry and Wood
Technology. 62 (2007): 333–336.
4. R. WASIELEWSKI, K. OR OWSKI, S. SZYSZKOWSKI, E. WNUKOWSKI, Pi a
tarczowa z rowkami wiórowymi. Politechnika Gda ska. Zg oszenie patentowe P382274 z
dnia 24.04.2007 (Patent pending).
5. R. WASIELEWSKI, K. OR OWSKI, S. SZYSZKOWSKI, E. WNUKOWSKI, Pi a
tarczowa z naci ciami mi dzy ostrzami. Politechnika Gda ska. Zg oszenie patentowe nr
P382273 z dnia 24.04.2007 (Patent pending).
6. R. WASIELEWSKI, Circular saws with closed chip grooves. Annals of Warsaw
University of Life Sciences -SGGW. Forestry and Wood Technology. 66 (2008): 171–
174.
421
Streszczenie: PrzydatnoĞü diagnostyczna rozkáadu segregacji wiórów na przykáadzie
przecinania drewna. W niniejszym artykule opisano drogi transportu wiórów w procesie
przecinania drewna i ich wp yw na rozdrobnienie wiórów. Przedstawiono równie wyniki
bada rozk adu segregacji wiórów powstaj cych w procesie przecinania pi o powszechnie
stosowanej konstrukcji i pi z domkni tymi rowkami wiórowymi.
Pro-ecological technology of wood sawing with circular saw blades
R. WASIELEWSKI, K. A. OR OWSKI
Abstract: Pro-ecological technology of wood sawing with circular saw blades. In this paper material and
energy-saving potential of sawing with circular saw blades is described. Furthermore, examples of effects of proecological technology application in industry are presented.
Keywords: ecology, wood cutting, circular saw blade, circular sawing machine
INTRODUCTION
The ecological friendship is a basic demand, which is placed for contemporary
manufacturing processes.
In the field of wood sawing with circular saw blades, which belongs to basic cutting
methods in the wood industry, the ecological friendship first of all is connected with material
and energy-saving of the process. The application of the technologies in sawmills, which
allow the users to reduce raw material losses and energy consumption, gives measurable
advantages not only economical but also ecological [1 Orlowski, 2 Orlowski et al.].
REDUCTION OF RAW MATERIAL LOSSES IN THE SAWING PROCESS
An analysis of raw material losses arising in the sawing process reveals that their
value depends on (fig. 1A) [3 Wasielewski]:
- tooth overall set of the circular saw St,
- accuracy of the axial position of teeth in relation to the workpiece B,
- irregularity of surface after sawing Rt.
Thus, a reduction of material losses of the sawing process with circular saw blades calls for:
- a reduction of the tooth overall set of the circular saw (application of thin saw
blades),
- an increase of sawing accuracy,
- a reduction of the saw blade spacing.
The effects of those actions are presented in fig. 1. The reduction of the tooth overall set of
the circular saw, an increase of sawing accuracy and also a reduction of the saw blade
spacing could cause both an absolute loss and a relative loss, and additionally entails an
increase of the raw material yield of the sawing process.
423
A)
B)
R'
a)
Rt1'
Rt2'
b'
s'
11 szt.
St'
b)
G* min
G* max
St
b
s
10 szt.
B
Rt1
Rt2
R
Fig. 1. Effects of raw material losses while sawing of wood, where: a) material-saving sawing, b) traditional
sawing issue, A) theoretical sawing scheme, B) industrial examples of sawing with the same number and
dimensions of the obtained sawn lamellae
Sawing with raw material losses reduced can be called as a material-saving process.
The comparison to the traditional process (common used in sawmills) is the best method of
the effect assessment. Criteria of material-saving sawing effect could be: a reduction of the
absolute raw material losses (R’<R), a reduction of the relative raw material losses, an
increase in raw material yield or just a comparison of the lumber number obtained from the
determined workpiece input width. Another way could be a comparison of the workpiece
input width which is needed for receiving of the defined number of pieces as a result of
sawing process [3 Wasielewski].
EXAMPLES OF RAW MATERIAL- AND ENERGY-SAVING WOOD SAWING
Examples of industrial comparison of raw material- and energy-saving sawing with
the traditional re-sawing, with circular saw blades, are shown in fig. 1B and fig. 2.
In figure 1B an example of effects of material-saving sawing with a traditional
technology is presented. The assessment was done on the basis of the comparison of the ready
element number obtained from the same workpiece input width. In the analysed example the
obtained effect are as follows:
- about 10% larger raw material yield,
- for one circular saw roughly 16% less sawdust,
- power of the cutting process (per one saw) is about 16% lower. An example of the
material-saving sawing effects comparison to the traditional one on the basis of the total
workpiece width needed for the obtainment of the same elements is performed in fig. 2.
424
a)
b)
Material-saving
sawing
Traditional
sawing
c)
Fig. 2. Comparison of effects of the material-saving to the traditional sawing technology, where: a) general view
of the input raw material, b) workpiece total width for the obtainment of the same elements, c) distribution of
changes of the input workpiece width and circular saw blade spacing
In the presented example, the main material (as timbers) and side lumber (boards) were
obtained on the two arbor circular saw in industrial conditions (fig. 2b). The input raw
material, shown in fig. 2a, did not have the constant width and moreover workpieces differed
between each other with the width. The plank dimension D is the most crucial factor
determining the raw material yield. It was defined as a minimum width of the workpiece with
the absolute height. The dimension D in the batch of sawn planks changed as it is presented in
fig. 2c. The use of narrow-kerf circular saw blades allowed us to turn the spacing of circular
saws from the traditional case (fig. 2cA) into the material-saving sawing (fig. 2cB). In those
sawing conditions, from one hundred sawn pine planks have been obtained: 2×(76.9 + 35.5) =
224.8 pieces of side lumber in the case A, and in the case B 2×(82.4 + 44.2 + 6.1) = 265.4
items of the side lumber. Thanks to application of the pro-ecological technology there was
achieved:
- about 18% increase in the amount of the side lumber,
- roughly 16% less sawdust,
- about 16% a lower values of the cutting power consumption.
SUMMARY
The use of narrow-kerf saw blades and an increase of the sawing accuracy reduces the
both cutting losses and cutting energy consumption while sawing of wood. The better use of
425
the input raw material in the presence of the lower cutting energy consumption is the basis of
the pro-ecological technologies of wood sawing. The application of those technologies allows
the sawmillers to reduce raw material consumption and furthermore brings measurable
economical profits.
REFERENCES
1. K. ORLOWSKI, Materia ooszcz dne i dok adne przecinanie drewna pi ami. Seria
Monografie nr 40, Wydawnictwo Politechniki Gda skiej, Gda sk 2003.
2. K. ORLOWSKI, R. WASIELEWSKI, S SZYSZKOWSKI, E. WNUKOWSKI, The
effect of improved cutting conditions of the circular saw blade on precision of cutting.
Annals of Warsaw University of Life Sciences. Forestry and Wood Technology. 2007, nr 62, s. 100–104
3. R. WASIELEWSKI, Losses and raw material yield of wood sawing processes, Annals
71, 2010: (Ann. WULS-SGGW, For and Wood Technol. 71, 2010, in press)
Streszczenie: Proekologiczna technologia przecinania drewna piáami tarczowymi. W
niniejszym artykule opisano mo liwo ci materia o- i energooszcz dnego przecinania pi ami
tarczowymi. Przedstawiono równie przyk ady efektów zastosowania proekologicznych
technologii przecinania w przemy le.
University of Technology, Narutowicza 11/12, 80–233 Gdansk, Poland
Selected mechanical properties of one-year old twigs of Salix acutifolia
IWONA WIADEREK, BOGUS AWA WALISZEWSKA
1
Abstract: Selected mechanical properties of one-year old twigs of Salix acutifolia.
The article discusses selected mechanical properties of willow (Salix acutifolia) twigs. The performed
investigations involved determination of the static bending strength as well as the assessment of the elasticity
modulus and strain. The experimental, one-year old willow twigs derived from the Hell Peninsula, both from the
side of the Baltic Sea and of the Puck Bay.
Keywords: willow, mechanical properties, static bending strength
INTRODUCTION
Within the willow family (Saliceacae), the following three genera are distinguished:
poplar (Populus), chosenia (Chosenia) and willow (Salix) with willow represented by the
greatest number of species ranging from 300 to 500 (Boraty ski and Boraty ska, 1990;
B kowski et al., 1995; Pr dzy ski et al., 1996; Waliszewska et al., 1999). They are
heliophilous plants of low soil requirements. Most willow species grow on wet sites,
sometimes even periodically flooded but there are a number of species that can be planted on
dry soils, sometimes even on sands and dunes.
Salix acutifolia os one of the species that is exceptionally tolerant as regards soil and
that is why it has found wide application in sand consolidation (Seneta, Dolatowski, 1997).
Salix daphnoides var. acutifolia Willd. – violet, sharp-leaved willow, occurs in the form of
bushes up to 6 m or trees – up to 10 m in height. Salix acutifolia is characterised by long, very
elastic twigs, green with sour-cherry colouring on one side. Its main application is planting of
shifting sands (Szczukowski et al., 2002). This species is particularly numerously represented
along the seashore line as it withstands unfavourable site and climatic conditions (Pr dzy ski,
Waliszewska, 1998). The Sea Office in Gdynia strongly supports wide introduction of
plantations of this species as one of the biological methods of consolidation of the technical
shoreline zone (Pestka 1996).
Willows are plants which provide a natural barrier between water and land,
additionally, confining migration of mineral fertilisers to water. Furthermore, when placed
appropriately in the riverbed, they can slow down its current thanks to strong anchorage to the
bed by the well-developed root system (Waliszewska and Pr dzy ski, 2005).
Knowledge of strength indices constitutes the basis of economic application of wood
in all kinds of constructions. Timber strength exerts a considerable impact on values of
acceptable strains and the way of its utilisation. Willow wood is an anisotropic and
hygroscopic material. Examination of its mechanical properties require taking into
consideration many different factors of which anatomical direction and wood moisture
content as well as the number and distribution of structural defects exert a strong influence on
wood strength and possibilities of its application. According to Pr dzy ski and urakowski
(1986), in processing practice, our knowledge of the wicker bending strength is most
important. This opinion is confirmed by Korzeniowski (1968) who also maintains that, for
practical reasons, the determination of mechanical properties of wickers is interesting both for
industry and producers of industrial wicker.
427
A cycle of investigations was conducted at the Institute of Chemical Wood
Technology of the Pozna University of Life Sciences concerning specificity of development,
chemical composition, content of heavy metals and mechanical properties of willows from the
Hel Peninsula. Initial experiments were carried out on twigs of varying age ranging from 2 – 5
years. On the basis of the obtained results, it was decided to examine wickers of Salix
acutifolia willow of the same age from bushes growing in different places of the Hel
Peninsula both from the side of the Baltic Sea and from the side of the Puck Bay. The first
series of experiments was performed on one-year old willow twigs collected from the
following places: W adys awowo, Ku nica and Hel.
EXPERIMENTAL MATERIAL AND RESEARCH METHODOLOGY
The experimental material included one-year old willow (Salix acutifolia) twigs
collected following one full vegetation cycle. The twig samples were collected from randomly
selected 10 plants all growing on the Hel Peninsula in W adys awowo, Ku nica and Hel
situated either on the side of the Baltic Sea or the Puck Bay. For comparative purposes,
investigations were also carried out on willow twigs obtained from Salix daphnoides var.
acutifolia Willd. from Obory near Kwidzyn. Mechanical properties were determined on oneyear old twigs with and without bark. Samples 160 mm long were cut out from middle
sections of twigs. Experiments were conducted on 10 twigs with bark and 10 twigs without
bark following their hydrothermal processing. The diameter of twigs was established with the
assistance of electronic callipers. The moisture content of the examined twigs amounted to
about 7% and differences in moisture content between individual twigs did not exceed 0.6%.
Investigations of the static bending strength were performed on ZWICK testing
machine. Samples were bent with a concentrated force applied at the middle of support
spacing which amounted to 10 cm.
Figure 1. Testing machine with equipment used for
experiments on static bending strength
Figure 2. Willow twig deflection under the
influence of applied force
Additionally, the static bending strength was also calculated according to the
following formula (Korzeniowski 1968):
428
Rg
8l
SD 3
Pn
where: Rg – twig bending strength ( MPa),
l – bending span (support spacing) (cm),
Pn – destructive force (N),
D – twig diameter (mm).
RESEARCH RESULTS AND THEIR DISCUSSION
The highest static bending strength reaching 148.91 MPa was determined in debarked
twigs collected from a small town, called Hel from bushes growing on the side of the Baltic
Sea. Twigs collected from the same side of the Hel Peninsula from Ku nica also showed high
static bending strength of 131.33 MPa. The lowest strength amounting to 111.02 MPa was
determined in twigs obtained from willow bushes growing in Hel but on the side of the Bay.
Low bending strength of 115.34 MPa was also recorded in twigs from Ku nica from bushes
growing on the side of the Bay as well as in twigs from W adys awowo - 116.86 MPa
obtained from bushes growing on the side of the sea. Control twigs from the plantation in
Kwidzyn were characterised by high static bending strength amounting to 140.26 MPa. These
values were exceeded only by twigs of S. acutifolia obtained from the town of Hel from
plants growing on the side of the Baltic Sea.
Table 1. Static bending strength of debarked twigs of willow Salix acutifolia
Place
W adys awowo
Ku nica
Hel
Kwidzyn
plantation
Side of the
shoreline
Elasticity
modulus
E Mod [MPa]
Static bendig strength
Rm
[MPa]
Strain
- Rm
[mm]
Sea
8805.43
116.83
10.51
Bay
9348.07
126.39
10.96
Sea
8375.85
131.33
12.34
Bay
7335.98
115.34
11.11
Sea
9482.70
148.91
12.80
Bay
7057.11
111.02
12.24
-
8640.28
140.26
13.84
The determined modulus of elasticity of debarked willow twigs from the Hel
Peninsula ranged from 7057. 11 MPa to 9482.70 MPa, whereas deflection – from 10.51 mm
to 12.80 mm. The above parameters determined for twigs obtained from the plantation
amounted to: 8640.28 MPa and 13.84 mm, respectively.
429
Table 2. Static bending strength of twigs with bark of willow Salix acutifolia
Place
W adys awowo
Ku nica
Hel
Side of the
shoreline
Elasticity
modulus
E Mod [MPa]
Static bendig
strength Rm
[MPa]
Strain
- Rm
[mm]
Sea
7674.38
85.35
6.35
Bay
6293.03
84.36
8.96
Sea
5955.03
75.93
8.70
Bay
5196.05
62.05
10.97
Sea
5293.24
63.10
10.39
Bay
5861.68
72.10
8.77
-
6800.68
89.61
8.67
Kwidzyn
plantation
Static bending strength of twigs with bark was by approximately 50% lower in
comparison with debarked twigs and ranged from 62.05 MPa to 85.35 MPa (Tab.2).
When analysing the experimental twigs with bark obtained from the Hel Peninsula, it
is clear that the highest strength was recorded in the twigs from W adys awowo, both from
bushes growing on the side of the sea – 85.35 MPa, and the bay – 84.36 MPa, whereas willow
twigs obtained from bushes growing from the side of the Puck Bay were characterised by the
lowest static bending strength – 62.05 MPa.
On the basis of the obtained research results, it can be said that willow twigs from
bushes growing in W adys awowo and Ku nica on the side of the Baltic Sea were
characterised by higher static bending strength than those growing on the side of the Puck
Bay,
Static bending strength
89,61
84,36 85,35
75,93
80
72,1
62,05
Bay
63,1
60
Sea
40
20
pl
an
ta
cj
a
el
H
u
id
zy
n
K
ad
ys
aw
ow
o
ni
ca
0
K
w
W
Strength [MPa]
100
Figure 3. Bending strength of Salix acutifolia twigs on the side of the Puck Bay
and the Baltic Sea
430
Analysing the research results of strength of willow twigs with bark derived from the
Hel Peninsula, it can be concluded that, irrespective of the place of growing, they all showed
lower static bending strength in comparison with the twigs collected at the plantation in
Kwidzyn whose strength amounted to 89.61 MPa (Tab. 2; Ryc. 3).
The determined elasticity modulus of willow twigs with bark derived from the Hel
Peninsula ranged from 5196.05 MPa to 7674.38 MPa, while their deflection - from 6.35 mm
to 10.97 mm. The above parameters determined for the twigs from Kwidzyn plantation
amounted to: 6800.68 MPa and 8.67mm, respectively.
RECAPITULATION
1. Debarked, one-year old willow twigs characterised by small diameters showed fairly
high static bending strength ranging from 111.02 MPa to 148.91 MPa.
2. Twigs with bark collected both from the side of the Baltic Sea and the Puck Bay
revealed static bending strength by about 50% lower than debarked twigs subjected to
hydrothermal treatment.
3. The twigs with bark derived from Kwidzyn plantation were characterised by the
highest static bending strength reaching 89.61 MPa, whereas twigs from the Hel
Penisula, irrespective of the place of their development, showed strength ranging from
62.05 MPa to 85.35 MPa.
REFERENCES:
1. B KOWSKI R., BRZOZOWSKA K., PR DZY SKI W. (1995): Akumulacja
wybranych metali ci kich w wierzbach w okresie wegetacji. PTPN, Wydzia Nauk
Technicznych, Prace Komisji Technologii Drewna
2. BORATY SKI A., BORATY SKA K. (1990): Systematyka i geograficzne
rozmieszczenie wierzby. PWN, Warszawa – Pozna
3. KORZENIOWSKI A. (1968): Badanie mechanicznych w a ciwo ci pr tów
wiklinowych. Folia For. Pol.Ser. B
4. PESTKA E. (1996): Zastosowanie wierzb w umacnianiu nadmorskiego pasa
technicznego. Mat. Konf. AR Pozna – Zielonka
5. PR DZY SKI W., BRZOZOWSKA K., RADOMSKA P. (1996): Sk ad chemiczny i
zawarto
metali ci kich w wierzbach rosn cych na Pó wyspie Helskim. X
Konferencja Naukowa Wydzia u Technologii Drewna SGGW, Warszawa
6. PR DZY SKI W., WALISZEWSKA B. (1998): Selected properties of Salix
acutifolia growing on the Hel Peninsula. Roczniki AR Pozna
7. PR DZY SKI W.,
URAKOWSKI M. (1986): Charakterystyka i ocena
przydatno ci wierzb krzewiastych dla przemys u wikliniarskiego. Nauka i szkolenie
kadr dla przemys u drzewnego. Warszawa 1986
8. WALISZEWSKA B., PODOBI SKI A., BOBKIEWICZ K. (1999): Sk ad chemiczny
wierzb i redukcja metali ci kich w hydrobotanicznych oczyszczalniach cieków. XIII
Konferencja Naukowa Wydzia u Technologii Drewna SGGW, Warszawa
9. WALISZEWSKA W., PR DZY SKI W.(2005): Chemical composition and heavy
metals content in willow trees (Salix caprea L.), Ann. Warsaw Agricult Univ.SGGW
For. and Wood Technol. No 57, 2005
10. SENETA W., DOLATOWSKI J.(1997): Dendrologia. Wydawnictwo PWN Warszawa
11. SZCZUKOWSKI S., TWORKOWSKI J., WIWART M., PRZYBOROWSKI J.
(2002): Wiklina (Salix Sp.) – Uprawa i mo liwo ci wykorzystania, Wydawnictwo
UWM Olsztyn
431
Streszczenie: Wybrane wáaĞciwoĞci mechaniczne jednorocznych prĊtów Salix acutifolia. W
niniejszej pracy scharakteryzowano wybrane w a ciwo ci mechaniczne jednorocznych pr tów
wierzbowych Salix acutifolia rosn cej na Pó wyspie Helskim z: W adys awowa, Ku nicy i
Helu, od strony Zatoki Puckiej i Morza Ba tyckiego. Badania obejmowa y okre lenie
wytrzyma o ci na zginanie statyczne, odkszta ce badanych próbek i modu u spr ysto ci.
Pr ty z kor zarówno od strony morza jak i zatoki wykazywa y mniejsz o ok. 50%
wytrzyma o na zginanie statyczne ni pr ty bez kory. Pr ty od strony Morza Ba tyckiego z
miejscowo ci W adys awowo i Ku nica charakteryzowa y si wi ksz wytrzyma o ci na
zginanie statyczne ni pr ty od strony Zatoki Puckiej.
Iwona Wiaderek, Bogus awa Waliszewska,
ul. Wojska Polskiego 28
60-637 Pozna
New idea in construction and performance of turning rotary knife.
GRZEGORZ WIELOCH1, MARCIN OSAJDA2, LUBOMIR JAVOREK3
MAREK ZASADA3, JANUSZ CIELOSZYK3, KRZYSZTOF CHMIELEWSKI4
1/
Poznan University of Life Sciences, Pozna , Poland
Marcin Osajda; „Nowy Styl” Factory, Rzeped , Poland
3/
Lubomir Javorek: Technical University in Zvolen, Slovakia
4 /
/ Krzysztof Chmielewski, Janusz Cieloszyk, Marek Zasada: West Pomeranian University of Technology,
Szczecin, Poland
2/
Abstract: The paper describes problems connected with tools having self-propelled rotary cutting edges. In
comparison with tools having immovable edges they are characterised by multiple increase of edge durability. In
spite of obvious advantages SPRT(e.g. durability of edges) problem causes their construction complexity as well
as limitation in machining of surface complexity .Thus there is a concept of their modernisation via fixing edge
engine spindle which creates driven rotary tool.
Keywords: turning wood, DRT – Driven Rotary Tools
INTRODUCTION
Among many different kinds of machining methods for machining cylindrical and
changing shapes mainly turning sanding and partly planning or milling are used.
For mass production of cylindrical rolls having invariable cross-section are usually used very
efficient turning methods like in the case of performing rolls in production of wooden
“garden” elements.
As far as machining of cylindrical cross-section is concerned a significant problems
are: a) low durability of edges, b) difficulty in obtaining required quality, c) low efficiency.
Individual support knives for lathes have shape and destination similar to known for ages
hand knives for turning. These are the
reasons for research and adaptation of new
ways of turning used in metal machining for
wood machining.
Interest in SPRT kind of tools for
metal materials gave also opportunity to
turning to this kind of machining in wood
machining [1,4,7,5,6,9,11].
It is justifiable because this kind of
immovable disc edges were for a long time
successfully used in profilling because of
lengthening of working time – longer Fig.1. Pine rolls of 10 cm diameter, length 300 i 400 cm.
cutting edge for dulling [9,10].
SELF – PROPELLER ROTARY TOOLS – SPRT
SPRT – Self-Propelled Rotary Tools are characterized by multiple edge durability growth in
comparison with immovable edges. They are also characterised by substantial reduction of
temperature in cutting area [2,11]. Described features of these tools enable to solve effectively
problems of machining for example [1-3, 7-11]. The principle of work of SPRT is shown on
Fig 2a .
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Self-rotation of a knife during machining process appears under influence of friction
forces which appear in the point of contact of tool flank surface and machined surface. In the
case of when angle =0° then the knife during machining doesn’t rotate but when angle 0°,
a substantial contribution to self-rotation of knife has friction of a moving chip on the rake
face. Form dependences given in literature [3,7,8,9] it appears that rotation speed of knife v0 is
directly proportional to machining speed v and of cutting edge inclination . So when cutting
edge inclination growth, rotation speed of knife v0 growth as well.
EXPERIMENTS CONNECTED WITH SPRT KNIVES
Tests of SPRT tools when machining metals were conucted lately in ITM ZUT in
Szczecin and in KOIPKM UP in Pozna fully certify effectiveness of application of these
tools [11].
In spite of evident advantages of SPRT like for example: lower cutting forces than in
fixed knives and higher durability there exist some disadvantages like their construction
complexity and limitations in diverse surfaces machining. Basic factor influencing quality and
cost of the tool is bearing unit which fixes cutting blade - Mitsubishi Carbide, Japan and
Rotary Technologies, USA, which not long ago started producing SPRT widely accepted and
used in industry.
NEW IDEAS IN CONSTRUCTION AND WORK OF KNIFE
The above listed and described technological limitations and relatively high cost of
SPRT induce new construction developments and new kinematics of such tools [1,2,3]. The
main stress is put on elimination of individual equipment of each tool in bearing unit which
fixes cutting blade. The promising development direction of idea of cutting with tools having
rotating blade is utilization of multi-axial turning centers having kinematic-moving structure
fitting the way of work of these tools. Fig. 3 shows conception of SPRT and the idea of work
of it in multi-axial turning centre with possibility of DRT (Fig 2b)
This idea gives possibility of utilization of disc knife in conventional lathes and
moulding machines with special equipment. The above described principle of work of SPRT
knife eliminates the problem of precise bearings work of cutting blade in each particular tool.
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Fig. 3. SPRT: the conception of fixing and work of SPRT knifing multi-axial turning centre.
The role of bearings work takes moulding machine spindle. Simultaneously the
problem of alternative choice of SPRT or DRT is solved. The tool can work as SPRT after
uncoupling tool`s spindle drive or as DRT when driven directly from spindle. DRT
performance can be in such situation considered as basic (more general containing also SPRT
alternative). The construction of the tool becomes
exceptionally simple (Fig.4) and the cost of production
many times smaller. One should however become
acquainted with patent restrictions which appeared lately
like for example: patent US7156006 of Gregory Hyatta
form 2007 (Fig. 4). Cutting force during machining with
above described knives works in the direction of their
biggest stiffness (direction similar to direction of rotation
axis of a tool) which profitably influences course and
stability of machining process. Stiffness in direction
perpendicular to axis depends on throat distance and
Fig.4. Tool for turning fixed to
.cutter arbor diameter of a chosen knife edge.
spindle.patent US7156006
Currently used systems of multi-axis steering CNC make
possible programming both linear displacement (axis X, Y, Z), and angle displacement of
spindle axis. It enables any tool position to machined surface.
Programmed in CNC change in setting is of significant importance when choosing
optimal cutting conditions.
Thanks to continuous and simultaneous positioning of required axis of machine tool the
problem connected with machining of rolls having non-standard profile is resolved which is
of great importance in wood industry. Continuous positioning of tool axis during machining
of non-standard profiles (for example curvilinear) is vital for constant machining conditions
along turned roll profile. It ensures precise rotations of cutting disc in SPRT method. The
effective programming of rolls machining when they have non-standard profiles needs in
future enlarging of appropriate programming options in CAD/CAM systems.
435
EXPERIMENTS AT UTILISATION OF PROPELLED KNIFE ON SPINDLE
IN WEST POMERANIA UNIVERSITY OF TECHNOLOGY
In Institute of Mechanical Technology in
West
Pomerania
University
of
Technology
were
conducted
introductory tests verifying development
legitimacy of new concept of SPRT and
DRT knives work fixed to spindle. The
tests were conducted on two stands
which had required kinematic-movement
unit. One stand was based on kinematic
unit of lathe grinder (Fig.5), the other
one was based on vertical milling
machine.
On stand one machining tests on maily soft
materials were conducted (for example
Fig. 5. Adaptation of lathe grinder for machining tests
wood, plastic, aluminium).
with rotating disc . Linear and rotary axis movements are
For this purpose a rotary disc folded knife
drawn in the picture
was projected (Fig.6).
It had cutting edge from high-speed. steel HS18-0-1-0 (SW18), diameter Dc = 33 mm and geometry
suting machining of above mentioned materials.
Fig.6. Rotating disc knife for soft materials [11]
The course of machining with above mentioned knid of knife was characterized by results
very similar to results obtained during earlier SPRT [5-10]. The work effect of SPRT that is
forcing rotation of disc only by cutting forces was obtained by uncoupling of tool spindle
drive.
CONCLUSIONS
The above described conception of machining with rotary disc knives solves significant
technological and working difficulties typical SPRT tools [1,4-8]. The expected effects of
their usage can be characterized as following:
1. Simplification of construction and production technology of tools which results in
substantially lower costs. The construction of such knives is less complex than
conventional knives with fixed discs.
2. Removal of limitations of usage of a tool either as SPRT or DRT.
3. Enlargement of technological possibilities of new machining way SPRT/DRT.
Typical SPRT knives are basically destined for machining of cylindrical or tool face plains
which is the result of necessity of remaining stability of tool angles in the setting unit. Using
lathe centres programmed in many axis one can provide stability of working angles of cutting
edge also during turning of conical, spherical and curvilinear surfaces [1,2,3].
436
REFERENCES:
1. CHMIELEWSKI K., CIELOSZYK J., ZASADA M.: NarzĊdzia z obrotowymi
páytkami skrawającymi – moĪliwoĞci technologiczne i efekty stosowania. Konferencja
Naukowo-Techniczna „Projektowanie Procesów Technologicznych”. Pozna 2006.
2. HOSOKAWA A., UEDA T., ONISHI B R., TANAKA R., FURUMOTO T.: Turning
of difficult-to-machine materials with actively driven rotary tool. CIRP Annals Manufacturing Technology 2010.
3. HARUN S.: Cutting Mechanics of Turning with Actively Driven Rotary Tool.
Department of Mechanical Engineering, Kobe University, Japan, 2008.
4. JAVOREK L., HRIC J.: Obróbka drewna narzĊdziami z obracającą siĊ krawĊdzią
skrawającą. Obróbka Skrawaniem, Innowacje, IOS Kraków, 2008.
5. NAKAJIMA K.: Effect of Rotary Cutting Tool Posture on Machining Performance
Utilizing Multi-Tasking Lathe. Tokyo University of Agriculture and Technology,
Japan, 2008.
6. STJERNSTOFT T.: Machining of some difficult-to-cut material e with rotary cutting
tools. The Royal Institute of Technology, KTH, Stockholm 2004.
7. WIELOCH G., OSAJDA M., MOSTOWSKI R.: Narz dzia do toczenia z
samoobracaj cymi si p ytkami i ich zastosowanie przy skrawaniu drewna, Obróbka
Skrawaniem, Innowacje, IOS Kraków 2008, 408–416.
8. WIELOCH G., OSAJDA M.: Construction of self-propelled rotary tool (SPRT) for
wood turning. Annals of Warsaw Agricultural University – SGGW, Forestry and
Wood Technology No, 2007.
9.
. .:
.”
,
1986.
10.
. .,
. .,
. .
. .
.
,
1987.
11. ZASADA M., CIELOSZYK J., CHMIELEWSKI K.: Nó tokarski czo owy –
narz dzie z obrotowym ostrzem skrawaj cym. w Obróbka skrawaniem. T.3.
Zaawansowana technika, H. Lato (red.). Uniwersytet Technologiczno-Przyrodniczy
w Bydgoszczy, Bachorze 2009.
Streszczenie: Nowa koncepcja konstrukcji i dziaáania obrotowego noĪa tokarskiego. W pracy
przedstawiono problemy zwi zane z narz dziami z samo-obrotowymi ostrzami skrawaj cymi
(SPRT – Self-Propelled Rotary Tools) Odznaczaj si one kilkudziesi ciokrotnym wzrostem
trwa o ci ostrza w porównaniu z narz dziami o ostrzach mocowanych na sta e. Cechuje je
równie znacz ce obni enie temperatury w strefie skrawania. Pomimo oczywistych zalet
narz dzi SPRT problemem jest nadal ich z o ono
konstrukcyjna oraz ograniczenia
mo liwo ci obróbki z o onych powierzchni. St d koncepcja ich modernizacji polegaj ca na
mocowaniu ostrza na wrzecionie silnika i wymuszonym nap dzaniu ostrza (DRT – Driven
Rotary Tools).
ACKNOWLEDGEMENT: This research has been realized with support of the grant 68/2009/gp
Autors adresses:
1/
Grzegorz Wieloch: Poznan University of Life Sciences, 60-627 Pozna , Wojska Polskiego 38
2/
Marcin Osajda; „Nowy Styl” Factory, Rzeped ,
3/
Lubomir Javorek: Technical University, 960-53 Zvolen, T.G.Masaryka 24,Slovakia.
/
Krzysztof CHMIELEWSKI, Janusz CIELOSZYK, Marek ZASADA: West Pomeranian University of
Technology, Al. Piastów 19, 70-310 Szczecin
Computerised production line of carpentry products –
processing centre Hundegger K-2
GRZEGORZ WIELOCH
Pozna Uniwersity of Life Sciences, 60-628 Pozna , al. Wojska Polskiego 28, Poland
BOLES AW PORANKIEWICZ
University of Zielona Góra, 65-516 Zielona Góra, ul. Prof. Z.Szafrana 4, Poland
Abstract: Electric hand tools like for example sawing, mortising, milling, grinding, drilling or sanding machines
for wood processing have been commonly used in carpentry however lately in carpentry more and more
computer programmes are being used - based on CAD such as WETO, SEMA or DIETRICH. These
programmes used in construction projecting cooperate with digitally driven processing centres such as for
example Hundegger K-2 and K-3 which are able to perform with high accuracy the most difficult and
complicated elements of roof rafter framing. It saves time 30% in joints production with the same precision of
performance.
Keywords: carpentry, roof rafter framing, joints
INTRODUCTION
Roof is a construction covering a building and protecting its interior against unfavourable
influence climatic factors. Wood construction of roof is roof rafter framing [1, 2, 3].
Wood delivered for roof construction or to carpentry business performing a roof has
dimensions close to required ones. To process needed elements or constructions squared logs
should be sorted and well-matched to a given place and construction.
That is why we can state that during carpentry work we have to deal with:
x selection of wood,
x distribution (tracing) of elements,
x machining, mainly transverse and oblong cutting, shaping elements and dimensioning
them,
x machining aiming at another type of cutting that is performing and building up of joints
(mortising, drilling wholes etc.),
x impregnation of wood,
x assembly of elements in the place of building-in.
In order that the machining is performed properly and elements during fixing go together
machining places have to be adequately traced. The base for allocation is architectural project,
working or workshop drawings according to which markings of natural dimensions are
performed. They can be drawn on boards or panels. Markings for big constructions are drawn
on floors made from smooth boards or panels. [4]
Although firms make effort to precisely perform joints; precision of joining rafters leave lot to
be desired.
Hence attempts to construct equipment making easier to accomplish with high accuracy the
most difficult and complicated elements of roof rafter framing. The first automatically driven
devices for wood cutting were constructed in the beginning of the sixties of twentieth century
/Fezer 1963/.
DEVICES FOR CARPENTRY PRODUCTION
In 1984 Hans Hundegger demonstrates facility for performing carpentry joints driven by a
computer, which was used for building houses of frame construction (timber frame). Also
other firms at that time develop a wide range of facilities for carpentry production from very
438
simple solutions (AVOLA) to very complicated ones (e.g.: KRÜSI AG, UNITEAM)
[http://www.kruesi-ag.ch/website.php]
Carpenters started to build houses with timber frame construction using computer
programmes (e.g.: CADWork, Zirbel, S & S, Dietrich, Sema). In general data from projects
are passed on to computer driving production line (manually or automatically).
The computer decides which tools to use for production of a given element (e.g. column – Pin
joint) and how to produce elements from a given set of tools in the most effective way.
www.hundegger.de/ (august 2010)
HANS HUNDEGGER 6-AXIS MULTI-OPERATION MACHINE TOOL FOR TIMBER
ELEMENTS FOR BULDINGS` CONSTRUCTION
Hundegger K-2 robot is a machine tool designed for accomplishment of roof rafter framing.
One can perform on it not only rafter framing but also hip rafters, valley rafters, jack-rafters,
angle braces, columns purlins and wall plates additionally all elements of stairs can be
prepared as well.
Fig.1. Machining centre Hundegger K-2 [www.hundegger.de/]
The main advantage of this model is machining with one fixing of material in clamping jaws
of two feeding carriage which determines material in relation to machining tools. It is even
included in the name of machining machine K-2 "Zweihandsystem".
Fig. 2 and 3. The work principle of mobile wagons during joint milling [www.hundegger.de]
439
The new transport and positioning system with two guide and positioning wagons gives
accurate cuts even with bowed or twisted timber.
B
A
C
B
A
A
C
Fig.4. The scheme of work principle of carpentry products line:
A: guide and positioning wagons, different wagons settings in reference to machined tool
B: reference line,
C: the universal mill.
This principle is of course also valid for the other tools such as saw, drill units, milling etc.
The wood is held in position directly at the point of operation, so that a bow or twist does not
affect the accuracy of the joinery (fig 3.)[5].
Performing tolerance: 1/10mm -x axis, 1mm over 8 m - y axis.
Hundegger 6-axis multi-operation machine tool is additionally equipped in:
driving centre equipped in computer with monitor,
multi-functional disc saw which enables cross cutting of timber which has traverse
dimentions from 20 x 50 mm to 300 x 450 mm (optionally 625 mm or 1250 mm) at
any length (from 0,8 m),
high-precision feed rolls and chain ones (punctually covered with rubber),
cutter head with possibility of fixing shank cutter or plain milling one,
drilling head with possibility of fixing different length and diameter drills,
chain saw enabling performance of very precise cuts with perpendicular edges,
possibility of data input via EKP programme with graphical presentation or from all
available programmes Abbund and CAD.
Intelligent multi-process driving enables rational working process (machining) without
classification of timber elements. Timber elements are taken for processing and next
automatically is chosen construction element (from earlier prepared list) best fitting
downloaded material. The element is machined and after working process is marked as
finished.
Another element enabling performance of different cut-outs in logs is usage of turn table or
space enabling rotation of spindle base at 3600 in different plains.
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Fig. 6. With the 5-axis mill, compound conical dovetail connections can be precisely milled on rafters, hip and
valley beams.
6-axis machining unit with 5 degrees of freedom enables additionally change inclination axis
and milling angle, make wholes including conical wholes, grooves etc. 6-axis machining can
perform so complicated timber joints which are presented in Fig 6, 7 and 8 at low costs.
Fig. 7. Log milling - one can notice possibility of change of axial location of working spindle.
441
Fig.8. Samples of carpentry elements made by K2 Hundegger production line[www.hundegger.de].
CONCLUSIONS:
Using Hundegger K-2 robot for production of carpentry elements allows very precise, fast and
economical production of new and traditional patterns of timber constructions. As all
machines it is dependent on experience and knowledge of operator. Usually elements are
machined collectively (cutting, milling, drilling, marking) which raises performance precision
in comparison with precision of traditional carpentry methods. The K-2 robot needs only one
442
person with fork-lift truck for servicing. The disadvantage is high price starting from 120 000
EUR.
REFERENCES:
1. Grzyb W. (2007): Roboty ciesielskie, Wydawnictwo KaBe, Krosno
2. Kopkowicz F. (2009): Ciesielstwo Polskie, Wydawnictwo Arkady, Warszawa,
3. Lankiewicz W., Zdziarska-Wis I. (2008): „Technologia - ciesielstwo”, WSiP,
Warszawa,
4. Walicht K.: Przegl d narz dzi u ytkowanych przy wykonywaniu wi by dachowej,
Pozna 2010. (praca dyplomowa)
5. Wieloch G.: „Hundegger -– materia y dydaktyczne,
6. http://www.hundegger.de/ (august 2010)
7. http://www.kruesi-ag.ch/website.php
Streszczenie: Skomputeryzowana linia do produkcji wyrobów ciesielskich - centrum
obróbcze Hundegger K-2. W artykule opisano lini do produkcji wyrobów ciesielskich K-2
firmy Hundegger. Przedstawiono dwa rozwi zania na których bazuje obrabiarka a
mianowicie: system podawania i mocowania elementów drewnianych w czasie obróbki z
pomoc dwóch wózków ze szcz kami mocuj cymi elementy. W obrabiarce zastosowano 6
osiowy system obróbczy z 5 stopniami swobody dla mo liwo ci obróbki z ka dej strony
belki. Przedstawiono przyk adowe mo liwo ci wykonania elementów wi by dachowej na
omawianej linii. Zastosowanie linii Hundeggera do wykonywania elementów ciesielskich
pozwala na bardzo precyzyjn , szybk i ekonomiczn produkcj elementów konstrukcji
drewnianych. Elementy obrabiane s zazwyczaj cznie (ci cie, frezowanie, wiercenie,
znakowanie) co znakomicie podwy sza precyzj wykonania w porównaniu z dok adno ci
konwencjonalnych metod wykonywaniu stolarki. Do obs ugi potrzebna jest tylko jedna osoba
z wózkiem wid owym. Wad jest cena zakupu nowej maszyny zaczynaj ca si od oko o
120.000 euro.
Grzegorz Wieloch, Pozna University of Life Science , Poland, [email protected],
The treehouse
GRZEGORZ WIELOCH
Abstract: The treehouse. Treehouses although not popular in Poland are of great interest in other European
countries that means that wood products prducers are interested in their production. This kind of production
needs usually an individual project and a great deal of hand work during assembly in a tree which results in
measurable advantages to producers. Also treehouses themselves are a great attraction for children as the can be
equipped in chute, treillage, tightrope, climbing wall which except for superb fun is also a possibility to versatile
and harmonious development of a child.
Keywords: treehouse, play in a garden,
INTRODUCTION
Treehouses gain in Poland more and more followers. The base of their popularity are
advantages of the construction material – wood that is its construction durability, good
isolation, small thermal inertion and high aesthetical value.
Wood makes possible construction of treehouses of different dimentions, architecture and
technologies.
A great number of firms processing wood have wide range of products such as timber houses
for whole year living, summerhouses, garden sheds and treehouses.
These are mainly to be constructed on the ground most frequently on four legs and very often
connected with playground elements such as chute, treillage, tightrope, climbing wall etc. The
natural need of children playing in the garden is climbing trees. It might be caused by atavism
as according to some theories our ancestors moved from living in the heads of trees on the
ground which was much more dangerous place to live.[3]
.
Fig.1. Examples of wooden houses for children constructed on four legs [11]
At present some native tribes which live in forests in Indonesian part of New Guinea
build their unusual treehouses up to 40 meters high fo safety reasons.[6]
444
Hence there is no surprise in childrens`
dreams about a treehouse which is an area to
play out of sight of grown ups. Such a
treehouse is also an area where a child can
test its phisical durability thanks to such
elements like: chute, treillage, tightrope,
climbing wall and cobweb which are
additional attraction of such a place (Fig.2).
The biggest attraction of a treehouse is of
course its high location. A very popular
supplement of treehouse arrangement is so
called cobweb – constructed from specially
lace-up ropes which appropriately fixed
Fig.2. Play elements round a treehouse
enable climbing so adored by children. They
can also be element protecting against falling
down [ 1,2,4].
Equipping a house in chute, treillage, tightrope or climbing wall one can not only provide
great entertainment for a child but also possibility of versatile and harmonious development of
a child. A child can also hide there his or her “treasures” and has a fantastic place for playing
and meeting other children. Such a house can be an alternative to a tent very often pitched in
gardens.
Fig 3. Treehouse for one tree [9]
The design is not so modern but have very
exclusive interior. Blue Forest is producer
of wooden houses destinated both for
ecological purposes for example treehouses
for pupils (nature observation) as well as
very exclusive hotels and entertainment
parks. Price of these houses is also vry high
and ranges from 170 to 250 £ for square
feet! which equals ffom 1828 to 2688 £ for
one square meter [7,8,9].
Only few Polish firms which produce
treehouses offer their production according
to different projects. The main condition to
have a treehouse executed is having an
appropriate
tree
by
a
customer.
Fig.4. Treehouse for several trees [
Fig. 5 and 6. Treehouse without additional supports
445
Construction projects on websites are only outlines of ideas possible to process. One should
keep in mind that as there are no two idencical trees there are no two identical treehouses. A
treehouse in the garden is always unique one.
Treehouses can be devided according to:
a) number of trees used as support
- treehouse for one tree(Fig.3)
- treehouse for several trees (Fig.4)
b) construction of support
- without additional support
(on limbs) (Fig.5)
- with supports based on trunk (braces) - (Fig.2 i 3)
with additional supports based on ground (Fig.4)
Fot. Adam Kozak
A treehouse can of course be self-constructed. The cost of such a house is around from 2000
PLN (cost of materials) and 250 hours of work. At least two people have to work together
because of work at a height above ground. The best place to choose is strong, healthy trunk
preferably with extensive limbs. The best kind of trees for such constructions are oaks,
beeches, ashes although they can also be constructed on lime-trees, chestnuts, pines, firs,
willows and old fruit trees.
CONCLUSION
Treehouse production is a part of wood production, which is of low interest in Poland.
Processing of such houses is executed either by carpenters or by people themselves. The
aspects limiting production are lack of suitable trees or fear that children can harm
themselves.
446
REFERENCES
1. JAMPOLSKA L.: Domek dla dzieci - na drzewie. adny dom.
2. http://ogrody.gazetadom.pl/ogrody/ 2008-05-20 (20.6.200).
3.
CZY SKA M., KOSMALA M.: Ogrody szcz liwego dzieci stwa. adny dom
2005-05-20.
4. Wracamy na drzewa? Ogrody.Gazetadom.pl,22 sierpnia 2008.
5. Zakrzewska A.:Ogród dla dzieci - zabawa w zielone2008-05-14,
6. http://forum.budujemydom.pl/Domek-na-drzewie-dla-dzieci. (lipiec 2010)
7. http://alternatywnedomy.blogspot.com/ (lipiec 2010)
8. http://forum.muratordom.pl/showthread.php?137035-Domek-na-drzewie (1.7.2010)
9. http://www.etnodizajn.pl/teoria/biblioteka-opinii/domek-na-drzewie
10. http://www.drewniane.czest.pl/ (5.7.2010)
11. http://brykacze.pl
Streszczenie: Treehauses. W niniejszym artykule opisano domki na drzewa dla dzieci.
Produkcja tych wyrobów jest z regu y produkcj wymagaj c indywidualnego projektu, a
tak e du ego wk adu pracy r cznej w czasie monta u na drzewie. Daje to wymierne korzy ci
producentom. St d produkcja ta wydaje si bardzo atrakcyjna. Równie same domki stanowi
niema atrakcj dla dzieci. Gdy mo na je wyposa y np. w zje d alni , drabink
gimnastyczn , lin do wspinania czy ciank wspinaczkow , co oprócz wspania ej zabawy
zapewnia równie mo liwo wszechstronnego i harmonijnego rozwoju dziecka
Pozna University of life Science. Wojska Polskiego 38,Poland
(Ann. WULS-SGGW, For and Wood Technol.. 72, 2010)
Comparison of traits pine timber used in skeletal constructions.
WIERUSZEWSKI MAREK., GOTYCH VIKTOR., HRUZIK GINTER J.,
MARCINKOWSKA AGNIESZKA, KRYSTOFIAK TOMASZ, LIS BARBARA
Faculty of Wood Technology of the University of Life Sciences in Pozna , Department of Mechanical Wood
Technology
Abstract: Comparison of traits pine timber used in skeletal constructions. The physical and mechanical
properties with respect to the relevant standards were defined and large samples with the application of three
different adhesives were obtained. Physical examination included figured, density and moisture content of
normative samples obtained from samples of large size. The study of mechanical properties of the samples
included the determination of elasticity of the average large-size module.
Keywords: wood, pine timber, construction
INTRODUCTION
Pine timber mechanical and physical properties are among the principal parameters
affecting suitability of timber material for its application, especially in building industry. The
term ‘wood defect’ refers to any wood irregularity found in timber whose presence may
reduce its functional or use value. Some timber defects violate its structure and reduce its
strength, e.g. holes left by insects , decay, while others such as surface colour changes of
timber like blue stain, are less dangerous.
Attempts are being made to achieve maximal quantitative efficiency of full-value
elements as the most desirable, as confirmed by numerous investigations in the field of timber
quality and its suitability for further processing, for example the study by Pachelski, ytecki,
Iskra (1966), Buchholz, Hruzik (1970), Cegiel, Hruzik (1974), Hruzik (1979) and co-workers.
This approach has become the basis for defining technological optimisation of timber
processing.
The aim of the study was to determine physical and mechanical properties of
harvested timber and glued timber assortments intended for building industry. The performed
investigation made it possible to obtaining data about strength parameters and suitability of
harvested sawn materials upgraded for production purposes by defect elimination and gluing.
METHODOLOGY AND RESEARCH RESULTS
A total of 75 glue pine samples were prepared for purposes of this experiment. They
were allocated into groups which differed regarding the applied glue and cross-section. The
experimental samples were obtained using three different glues employed in the production of
building glued materials.
x The samples were glued using the following glue JOWACOLL 102 20 – pine A
x The samples were glued using the following glue AKZO NOBEL EPI 8055 - pine B
The investigations of the elasticity modulus were carried out in accordance with the
PN-63/D-04117 standard.
During the performed experiments, in order to determine basic features of pine wood
for purposes of experiments, such physical properties as: annual increment, proportion of late
and early wood in annual increments, density as well as absolute moisture were determined.
Tables 1 and 2 illustrate high width variability of annual wood increments from which
sample were obtained. This may have exerted some influence on the observed negative strain
448
distribution in the course of mechanical loading and may have caused wood warping
following different desorption strains in the neighbouring layers of the element. The minimal
measured annual width increment in pine wood amounted to 0.30 mm, whereas the maximal
one – up to 5,30 mm.
Table 1.
Characteristic values of annual increment widths for whole samples “A”
Cross section blank (mm)
40x72
40x100
40x120
element
mm
element
mm
element
mm
1(G)
1,95
1(G)
1,51
1(G)
1,85
2
2,09
2
2,51
2
1,74
3(D)
1,76
3
1,57
3
1,82
4(D)
2,03
4
2,33
5(D)
2,05
1,96
average
1,93
1,90
Table 2.
Characteristic values of annual increment widths for whole samples “B”
Cross section blank (mm)
40x72
40x96
40x120
element
mm
element
mm
element
mm
1(G)
1,62
1(G)
1,90
1(G)
1,73
2
1,85
2
2,26
2
1,83
3(D)
1,57
3
1,84
3
1,86
4(D)
2,03
4
2,41
5(D)
1,71
average
1,68
2,01
1,91
The obtained research results confirmed significant variations in widths of annual
increments in neighbouring layers. Increment widths in relation to the layer of sample origin
and averaged results of all samples from a given batch were itemised and the difference in
ring distribution/graining was apparent. So, in the case of glued pine timber, the mean width
of annual increments ranged from 1,90 mm to 1,96 mm in group “A” and from 1,68 mm to
2,01 mm in group “B”.
The results of absolute moisture content investigations of large-sized timber samples
revealed that the differences between adjacent batten layers in samples did not exceed 2,5%,
so they fell within the acceptable interval of 5%.
The results obtained in the course of the performed experiments revealed that the
material obtained from glued pine timber was characterised by the density of 520 kg/m3.
Layers of glued pine samples were characterised by densities in the range of 490 kg/m3 to 557
kg/m3. When interpreting density results in relation to the position of the examined samples in
the large-sized sample it can be concluded that the timber material used to manufacture glued
elements did not have similar properties.
Table 3 collates characteristic values of the elasticity modulus for individual sample
batches.
449
Table 3.
Values of the elasticity modulus at 12% moisture content
Sample
symbol
2
elasticity module [N/mm
40x72(A)
40x100(A)
40x120(A)
40x72(B)
]
40x96(B)
40x120(B)
1
8595
8141
10926
11523
10244
10441
2
12484
10483
9738
10360
10889
9704
3
10572
10900
10959
9814
12036
9923
4
9098
9328
10012
12415
11676
9080
5
12471
9249
11494
9967
10554
10749
6
12007
9340
10909
8651
11701
10982
7
9718
11415
9797
12356
13288
9687
8
9319
9586
10847
10625
12573
8731
9
9560
10173
9883
11499
11370
10381
10
10621
7845
10851
12104
12142
9013
11
11488
10418
9496
12
11434
12341
9732
13
10411
11988
10533
14
11863
11326
10090
15
average
10444
9646
10541
12145
9752
9623
11110
11486
9878
It can be concluded from the research results on large-sized timber samples that timber
gluing reduced the spread of the elasticity modulus.
In addition, when large-sized timber samples were bent, the elasticity modulus
(Figure 1.)decreased with the increase of sample cross section. The obtained mean values for
solid timber were found to be at the level of 9 600 N/mm2. When the above values were
compared with the results given by Krzysik (1974) E=12 000 N/mm2, it was found that the
elasticity modulus of the examined solid wood was 27% lower. Glued pine samples exhibited
smaller spread of results than solid samples but even so they were 20% lower than literature
data.
450
12000
11500
E (MPa)
11000
10500
10000
9500
9000
8500
40x72(A)
40x100(A)
40x120(A)
40x72(B)
40x96(B)
40x120(B)
Samples symbol
Figure 1. Values of the modulus of elasticity at 12% moisture content
In addition, the elastic modulus in the course of bending of large-sized samples
decreased together with the increase of the sample cross section. Mean values for pine glued
samples reached 10518 N/mm2 and those for minimum and maximum – 7845 - 12573N/mm2.
RECAPITULATION
The following conclusions were drawn on the basis of the performed investigations
and measurements and the obtained results:
1. Basic physical properties for the examined raw material were determined. Mean
ring annual increment of pine elements was found to be at the level of 2 mm. The
examined raw material was narrow-ringed. Mean absolute moisture content at the
time of measurement was 10%. Mean timber density of glued pine samples was
determined at 520-542 kg/m3. The obtained mean results were similar to those
found in literature on the subject.
2. The elastic modulus of the examined large-sized samples was as follows: solid,
glued pine samples – 10518 N/mm2. The above results were lower than literature
data.
3. Part of large-sized samples was damaged in the course of investigations of the
modulus of elasticity. The most frequent cause of the damage was splitting of the
multi-spline glue bond along the length in tensile layers (bottom strip). It was,
therefore, concluded that the technology of joining of coniferous semi-finished
products along the length in a system of multi-spline joints affects, to a significant
extent, the strength of the obtained beams.
451
LITERATURE
1.
2.
3.
4.
5.
6.
7.
8.
9.
Buchholz J., Hruzik J.G.(1970): Z bada nad ustaleniem wymiernej zale no ci
pomi dzy jako ci sosnowego drewna tartacznego i produkowanych z niego
materia ów tartych. Roczniki WSR w Pozna .
Buchholz J., Hruzik J.G.(1973): Wp yw jako ci sosnowego drewna tartacznego na
struktur jako ciowo-wymiarow produkowanych k ód. Pr. Kom. Techn. Drewna
tom IV.
Cegiel E., Hruzik G.J. (1974): „Przydatno
tarcicy jod owej do produkcji
pó fabrykatów przeznaczeniowych”, Przemys Drzewny nr 4.
Hruzik J.G. (1979): Jako
sosnowego surowca tartacznego jako kryterium
optymalizacji produkcji elementów przeznaczeniowych. Fol. Forest Polonica, zeszyt
13.
Krzysik F. (1974): Nauka o Drewnie.
Pachelski M., ytecki J., Iskra M. (1966): Wydajno materia owa w produkcji
elementów meblowych. Prace ITD, nr 3.
PN-63/D-04117 „Fizyczne i mechaniczne w asno ci drewna. Oznaczanie
wspó czynnika spr ysto ci przy zginaniu statycznym”.
PN-77/D-04100 „Drewno. Oznaczanie wilgotno ci”.
PN-77/D-4101 „Drewno. Oznaczanie g sto ci”.
Streszczenie: Porównanie cech drewna sosnowego stosowanego w konstrukcjach
szkieletowych. Okre lono w a ciwo ci fizyczne i mechaniczne w odniesieniu do w a ciwych
norm przedmiotowych. W a ciwo ci fizyczne obejmowa y badania s oisto ci, g sto ci i
wilgotno ci
normatywnych
próbek
laboratoryjnych
pozyskanych
z
próbek
wielkogabarytowych. Badanie w a ciwo ci mechanicznych próbek wielkogabarytowych
obejmowa o okre lenie redniego modu u spr ysto ci.
Department of Mechanical Wood Technology
60-627 Pozna
tel./fax (061) 8487437
(Ann. WULS-SGGW, For and Wood Technol.. 72, 2010)
Glued elements for construction
WIERUSZEWSKI MAREK, GOTYCH VIKTOR, HRUZIK GINTER J., GO U SKI
GRZEGORZ
Faculty of Wood Technology of the University of Life Sciences in Pozna , Department of Mechanical Wood
Technology
Abstract: Glued elements for skeletal construction. Qualities of won design elements in research from
production of wood construction definite pine timber Work included comparison of specificity resistance and
with reference to proper objective norms with taking into consideration dimension partition of semi-finished
article qualitative raw material. The study of mechanical properties of the samples included the determination.
Keywords: wood, quality classification , glue timber products
INTRODUCTION
The objective of investigations is to determine the quality of structural elements
manufactured from sawn pinewood for the production of wooden constructions. The scope of
investigations comprises comparison of strength and quality properties of pinewood raw
material taking into consideration the origin and dimensional intervals of semi-finished
products (Buchholz 1975, Buchholz J., Hruzik. 1970, 1973, Dziewanowski 1965, Hruzik
1979).
The performed experiments will allow collecting data concerning strength parameters
as well as suitability of sawn materials for production purposes improved by elimination of
defects and gluing.
METHODOLOGY AND RESEARCH RESULTS
A total of 75 glue pine samples were prepared for purposes of this experiment. They
were allocated into groups which differed regarding the applied glue and cross-section. The
experimental samples were obtained using three different glues employed in the production of
building glued materials.
x The samples were glued using the following glue JOWACOLL 102 20 – pine A
x The samples were glued using the following glue AKZO NOBEL EPI 8055 - pine B
To compare static bending strength, solid samples constituting the initial material for
the production of layers of glued semi-finished elements were prepared.
During the performed experiments, in order to determine basic features of pine wood
for purposes of experiments, such physical properties as: annual increment, proportion of late
and early wood in annual increments, density as well as absolute moisture were determined.
The results obtained in the course of the performed experiments revealed that the
material obtained from glued pine timber was characterized by the density of 520 kg/m3.
Layers of glued pine samples were characterized by densities in the range of 490 kg/m3 to 557
kg/m3. When interpreting density results in relation to the position of the examined samples in
the large-sized sample it can be concluded that the timber material used to manufacture glued
elements did not have similar properties.
The next physical property affecting pinewood quality and usefulness is structure of
annual rings. According to earlier investigations (Kollmann), narrow annual rings in
coniferous timber indicate higher quality parameters (Krzysik 1978).. The largest mean width
453
of annual rings of battens (2.01 mm) was recorded for construction elements of sample B of
40 x 96 mm cross section. The smallest mean width of annual rings of battens (1.68 mm) was
recorded for construction elements of sample B of 40 x 72 mm cross section.
This may have exerted some influence on the observed negative strain distribution in
the course of mechanical loading and may have caused wood warping following different
desorption strains in the neighboring layers of the element. The minimal measured annual
width increment in pine wood amounted to 0.30 mm, whereas the maximal one – up to 5,30
mm.
The obtained research results confirmed significant variations in widths of annual
increments in neighboring layers. Increment widths in relation to the layer of sample origin
and averaged results of all samples from a given batch were itemized and the difference in
ring distribution/graining was apparent. So, in the case of glued pine timber, the mean width
of annual increments ranged from 1,90 mm to 1,96 mm in group “A” and from 1,68 mm to
2,01 mm in group “B”.
Static bending strength for model solid samples
For comparative purposes of the raw material, in the performed investigations, solid
samples in accordance with the PN-77/D-4103 standard were obtained. Laboratory samples
(free of defects) are characterized by greater strength than large-sized samples. Table 1
presents sample strengths obtained for samples from A and B raw material recorded at static
bending.
Tab.1 Static bending strength of model samples of A and B samples (Source: own research, Michnowicz 2008)
Zone
compressed
zone
central
zone
stretched
zone
Min
"A" Rg12 (MPa)
Average
Max
Min
"B" Rg12 (MPa)
Average
Max
53
77
97
49
71
90
51
66
90
53
59
85
50
81
97
47
79
93
Samples characterized by the lowest mean strength (66 and 59 MPa) were obtained
from central battens of both A and B samples of the construction elements. The highest mean
strength (81 and 79 MPa) was recorded for samples obtained from extended zones of battens
also of samples A and B of construction elements. The highest strength value recorded for a
single sample amounted to 97 MPa and the lowest – to 47 MPa. Mean differences between
the obtained results for group A and B were contained in the interval of about 2.5 to 10.5%.
Analyzing strength differences for the raw material used for external and central layers, the
strength for samples from compressed layers was found to be, on average, by about 14-16%
higher, while the strength for samples from the bottom, extended layers was by about 23-34%
higher, which confirms the appropriate selection of the raw material for the production of
large-sized elements.
Static bending strength for large-sized samples
Static bending strength is one of the most frequently applied strength tests which exert
a direct impact on designing of wooden constructions (Dzbe ski., Kozakiewicz, Krzosek
454
2005). Static bending strength was determined for large-sized samples in accordance with
methodological assumptions and the obtained results are presented in Table 2.
Tab 2 Static bending strength of large-sized samples of A and B samples (Source: own research, Michnowicz
2008)
Cross
section
(mm)
40x72
40x100
40x120
Min
25
24
27
"A" Rg15 (MPa)
Average
Max
39
48
35
55
29
31
Min
23
23
26
"B" Rg15 (MPa)
Average
Max
40
55
36
50
34
45
Construction elements 72 mm wide showed the highest mean strength (39 and 40
MPa). Semi-finished products 120 mm wide obtained lowest mean strengths (29 and 34
MPa). The lowest strength value (23 MPa) was recorded for the samples with 40 x 72 mm (B)
and 40 x 96 mm (B) cross sections, while the highest (55 MPa) - samples with 40 x 100 mm
(A) and 40 x 120 mm (B) cross sections. Mean differences between the obtained results for
groups A and B in dimensional intervals of 40 x 72 and 40 x 100 mm cross sections were
contained in the interval of about 2.5% mm in favour of beams of group B, while for the 40 x
120 mm cross section reached the difference of about 17%. Analyzing the results of strength
for beams from group A, the obtained mean discrepancy was at the level of about 10-25% and
for beams from group B – from about 6% to about 15%. Higher results were found for beams
of a smaller height dimension.
Comparing the obtained strength results for large-sized beams with the results
obtained on laboratory samples, it can be said that the results for the large-sized glued
elements, both in group A and B, were by about 47-54% higher in comparison with the
model.
Part of low bending strength values of construction elements could be blamed on the
delamination of the lap-joints. The most frequent place of such horizontal separation was the
glue-line area of the connection.
Research results presented in Table 3 characterize the strength according to the PN-EN
338 standard “Construction wood. Strength classes” where the bending strength is adopted as
a criterion.
Tab.3 Detailed presentation of strength classes (Source: own research, Michnowicz 2008)
strength classes:
C14
C16
C18
C22
C24
C27
C30
sign samples:
A 40x72 A 40x100 A40x120 B 40x72 B 40x100 B 40x120
Meets
Meets Meets
Meets Meets Meets
Meets
Meets
Meets
Meets Meets
Meets
Meets Meets Meets
Meets
Meets Meets
Meets
Meets
Meets
Meets
Meets Meets
Meets
Meets
Meets
Meets
Meets
-
455
C35
C40
-
legend:
Meets – the lot meets the standards
The results of classification shown in Figure 3 illustrate in a simple way that,
according to the PN-EN 338 standard, the examined large-sized samples achieved different
strength classes. It can be said that the examined wood raw material attained the strength class
on the level C16-C18. According to the presented classification, there were no significant
differences in the pine raw material glued with the applied resins.
According to the standard, the results of mean bending strength of laboratory samples
attained the highest strength class C40 for sample series. However, the final classification
belongs to the lowest results of fulfillment of the strength standard.
RECAPITULATION
The following conclusions were drawn on the basis of the performed investigations
and measurements and the obtained results:
1. The determined width of annual rings of the coniferous timber intended for the
production of semi-finished articles was contained within 0.3 to 5.3 mm interval
with the mean value of about 2 mm. So the examined raw material can be
classified as narrow-ringed. Mean densities of pinewood battens used for the
production of semi-finished articles are contained within the 520-542 kg/m3
interval and are higher in comparison with those given by Kollmann (490 kg/m3).
2. Empirically determined static bending strength for solid model samples from
pinewood raw material reached the following values: minimal - 47 MPa and
maximal - 97 MPa. The mean strength for the individual zones was contained
within the 59-81 MPa interval. The results obtained for the examined samples are
lower than the static bending strength for pinewood which, according to Wanin
amounts to 87 MPa, and to Göhre - 88 MPa.
3. The obtained results of static bending strength of semi-product (Fm,g,k = 19MPa)
compared with data PN-EN 1194 are too low to give a class of endurance for the
semi-product.
4. Low values of static bending strength, to a considerable extent, can be attributed to
displacements at the contact of the glue-line both at multi-wedge and layer joints.
It is worth noticing the disordered arrangement of glued battens - from radial to
tangential - which could have contributed to the decrease of strength parameters in
the examined samples.
LITERATURE
1. Buchholz J. (1975): Jako sosnowego drewna tartacznego jako kryterium ustalania
dojrza o ci technicznej drzew i drzewostanów. Roczniki Akademii Rolniczej
w Poznaniu, Zeszyt 55, Pozna .
2. Buchholz J., Hruzik J.G.(1970): Z bada nad ustaleniem wymiernej zale no ci
pomi dzy jako ci sosnowego drewna tartacznego i produkowanych z niego
materia ów tartych. Roczniki WSR w Pozna .
456
3. Buchholz J., Hruzik J.G.(1973): Wp yw jako ci sosnowego drewna tartacznego na
struktur jako ciowo-wymiarow produkowanych k ód. Pr. Kom. Techn. Drewna tom
IV.
4. Dziewanowski R. (1965): Analiza porównawcza jako ci sosnowego drewna
tartacznego z niektórych rejonów w kraju. Prace Instytutu Technologii Drewna,
zeszyt 1.
5. Hruzik J.G. (1979): Jako
sosnowego surowca tartacznego jako kryterium
optymalizacji produkcji elementów przeznaczeniowych. Fol. Forest Polonica, zeszyt
13.
6. Michnowicz M. (2008): praca magisterska KMTD
7. Dzbe ski W., Kozakiewicz K., Krzosek S. (2005): Wytrzyma o ciowe sortowanie
tarcicy
8. Krzysik F. (1978): Nauka O Drewnie. PWN Warszawa, wydanie :
9. PN-77/D-04103 „Drewno -- Oznaczanie wytrzyma o ci na zginanie statyczne”.
10. PN-EN 384, Drewno konstrukcyjne. Oznaczanie warto ci charakterystycznych
w a ciwo ci mechanicznych i g sto ci.
11. PN-EN 338, Drewno konstrukcyjne. Klasy wytrzyma o ci.
12. PN-EN 1194 Konstrukcje drewniane -- Drewno klejone warstwowo -- Klasy
wytrzyma o ci i okre lenie warto ci charakterystycznych
Streszczenie: Elementy klejone dla budownictwa szkieletowego.
W badaniach okre lono jako ci obejmowa o okre lenie pozyskiwanych elementów
konstrukcyjnych z tarcicy sosnowej do produkcji konstrukcji drewnianych. Praca obejmowa a
porównanie w a ciwo ci wytrzyma o ciowych i jako ciowych surowca w odniesieniu do
w a ciwych norm przedmiotowych z uwzgl dnieniem
przedzia ów wymiarowych
pó fabrykatów. Badanie w a ciwo ci mechanicznych próbek wielkogabarytowych.
Department of Mechanical Wood Technology
60-627 Pozna
tel./fax (061)8487437
Application of gas-steam mixture for wood drying purposes
M. WIERZBOWSKI1, J, BARA SKI2
Gda sk University of Technology, Department of Heat Technology, Faculty of Mechanical
Engineering, Poland
Abstract: Application of gas-steam mixture for wood drying purposes. The high cost of fossil fuel
and soaring interest rates have encouraged people in the wood industry to look for faster and more
energy-efficient methods to dry lumber. In this paper results of experimental study of flow pattern
and heat transfer during application of gas-steam mixture for wood drying purposes are presented.
Wood species, namely oak (Quercus L.) and pine (Pinus L.), were subject of steam drying process
in a laboratory kiln especially arranged for that reason. Main focus of those tests was to shorten the
time of drying process and afterward to check properties of wood. As results of mechanical
properties checking are presented in separate paper, here authors focused on numerical predictions
of uniform velocity and temperature profiles through the drying kiln, which is of great importance
for drying and also for energy saving. Predicted velocities were used in the laboratory kiln for tests.
Satisfactory results were obtained as the time of drying process was significantly reduced.
Keywords: wood drying, high-temperature drying, steam drying
INTRODUCTION
The dynamic development of the economy following Polish accession to
the European Union has not circumvented the wood industry. Thanks to the
development of the wood drying techniques using saturated or superheated steam
flows and gas-steam mixtures, waiting time for wood material for the furniture
industry will be reduced. Wood drying in addition to the technical importance
brings economic benefits, such as protection of wood against fungi and fracture,
which extends its life, facilitates machining and surface finishing of wood, fast
drying (e.g. steam) improves the balance of wood, and brings savings in transport
costs by reducing the weight of wood . The wood that has too high water content is
not useful for the production of furniture. Changes in size and shape, occurring in
the wood during the evaporation of water will affect the quality and dimensions of
the furniture. The resistance to weather conditions is also higher.
EXPERIMENTAL BACKGROUND
Drying in superheated steam is economically justified because of the shorter
processing time and reduced energy consumption, while it is, in this respect, better
than drying in hot air. In the absence of oxygen there is no oxidation processes in
the wood (although high-temperature of medium) and the danger of fire is
excluded. Short drying time, lower energy consumption and high quality of wood
after drying in an atmosphere of superheated steam are in favour of the use of this
method in industrial practice [1].
458
During drying water is evaporated from the wood and of great importance
here are:
• physical properties of drying agent,
• evaporation of water from the timber and free surface,
• hygroscopic properties of wood (depending on the species),
• hygroscopic equilibrium of wood ,
• changes in the wood during the evaporation of water.
During the drying of wood evaporation of free water does not change its
shape and dimensions. With the loss of water evaporation zone moves deeper into
the wood. The proper conduct of the drying process allows the extraction of more
water.
Wood species, namely oak (Quercus L.) and pine (Pinus L.), were subject
of steam drying process in a laboratory kiln. The kiln is equipped with heat
exchanger supplied by exhaust gases from furnace. Water, spread from two
nozzles, evaporates on exchanger’s surface. Generated steam, is distributed
between the wood stake by circulating fan. The dryer is dedicated for all timber
species of final moisture content to 6 % in the temperature up to 150oC. Detailed
description of laboratory kiln was presented previously [6, 7].
RESULTS
Experiments were carried out with Pomeranian region lumber of oak and
pine. Probes to measure moisture content inside wood are placed in the material so
that it was possible to measure moisture content in a number of characteristic
points of the kiln, i.e. in the middle of the boards or in the outer layers of the stack
Figure 1. Following figures presents the results of experimental works for oak and
pine lumbers.
a)
b)
0
75
0
50
850
150
0
4 elements
Fig. 1. Dimensions and location of probes for measuring temperature and moisture content
during experiment: a) stack of boards b) stack of timber
Hot water was supplied to the chamber to increase humidity and
temperature throughout the material in the initial stage of drying. Hot gases flow
through the heat exchanger to raise the temperature in the chamber. As far as
humidity and temperature grows, we start with the drying process. The process of
459
drying the material continues to achieve the assumed wood humidity of 10 % EMC
(equilibrium moisture content). The next process was the conditioning of wood slowly cooled down chamber with getting hot water to remove the stress in the
material which emerged during the whole process of drying.
Figure 2a presents the results of experimental work of moisture content
changes for pine lumber drying. The temperature of drying agent was about 100oC
and inlet velocity during heating stage was about 4,5 m/s. During drying and
conditioning process, inlet velocity was reduced by control system to about 2,5
m/s. This was necessary to achieve low velocity between wood layers to avoid
fractures of wood. Overall process took about 2,5 days. In Figure 2b photo of dried
pine lumber is presented. Slight colour changes and no fractures were reported.
a)
b)
22,5
Moisture content
20,0
Moisture content [%]
17,5
15,0
12,5
10,0
7,5
5,0
2,5
0,0
0
250
500
750
1000 1250 1500 1750 2000 2250 2500 2750 3000 3250
Time [min]
Fig. 2. The results of 7,0 cm x 7,0 cm pine lumber (Pinus L.) drying process using steam-gas
mixture: a) time dependence of moisture content, b) fractures and colour changes of wood.
Results of moisture content during oak lumber drying process are presented
on Figure 3a. In this case overall time was extended due to achieve proper level of
moisture inside wood as hot water was directed on a part of pile. Figure 3b presents
a view of dried oak lumbers. Because of high temperature and long time of drying,
structure and colour of wood were changed. Fractures of wood after this kind of
drying process can be also observed.
460
a)
b)
22,5
Moisture content
20,0
Moisture content [%]
17,5
15,0
12,5
10,0
7,5
5,0
2,5
0,0
0
500
1000
1500
2000
2500
3000
3500
4000
Time [min]
Fig. 3. The results of 7,0 cm x 7,0 cm pine lumber (Quercus L.) drying process using steam-gas
mixture: a) time dependence of moisture content, b) fractures and colour changes of wood.\
CONCLUSIONS
The results obtained from tests shows that drying time shortens of about 20
- 40 [%] what justifies further experiments. With the time shortened to 2,5 - 3 days,
it is assumed that also energy consumption for drying process of soft wood, such as
pine, will decrease. Next steps are planned with the use of coniferous and leafy
lumber.
ACKNOWLEDGEMENT
The financial assistance of Ministry of Science and Higher Education, Poland,
Grant N512 01232/3058 is kindly acknowledged.
REFERENCES
1. GARD W.F., RIEPEN M.: “Super-heated drying in Dutch operations”.
Conference COST E53, Delft, The Netherlands, 29-30 October 2008.
2. LANGRISH, T. A. G., KHO, P. C. S., and KEEY, R. B.: “Experimental
measurements and numerical simulation of local mass-transfer coefficients
in timber kilns”. Drying Technology, 10, 753-781, 1992.
3. LANGRISH, T. A. G., KEEY, R. B., KHO, P. C. S., and WALKER, J. C.
F.: “Time-dependent flow in arrays of timber boards: Flow visualization,
mass-transfer measurements and numerical simulation”. Chemical
Engineering Science, 48 (12), 2211-2223, 1993.
4. PANG S., SIMPSON I.G., HASLETT A.N.: “Cooling and steam
conditioning after high-temperature drying of Pinus radiata board:
experimental investigation and mathematical modeling”. Wood Science and
Technology 35 (2001), Springer Verlag 2001, s.487-502
5. SUN, Z. F., CARRINGTON, C. G., and BANNISTER, P.: “Dynamic
modeling of the wood stack in a wood drying kiln”. Chemica Engineering
461
Research and Design, Transactions Institution of Chemical Engineers, Part
A, 78, 107-117, 2000.
6. WIERZBOWSKI M., BARA SKI J., ST SIEK J.: „Gas-steam mixture
wood dryling”. COST E53 Meeting ''Quality Control for Wood and Wood
Products'' : EDG Drying Seminar ''Improvement of Wood Drying Quality
by Conventional and Advanced Drying Techniques'', Bled, Slovenia, April
21st-23rd, 2009.
7. WIERZBOWSKI M., BARA SKI J., ST SIEK J.: „Suszenie drewna
mieszanin parowo-gazow ”. Termodynamika w nauce i gospodarce.
Wroc aw, 2008 (in polish).
Streszczenie: Zastosowanie mieszaniny parowo-gazowej do suszenia drewna.
Zastosowanie mieszaniny parowo-gazowej do suszenia drewna. Badania
wysokotemperaturowego suszenia drewna zosta y zainspirowane konieczno ci
intensyfikacji wymiany ciep a i masy na potrzeby przemys u drzewnego w
zakresie: doskonalenia metod suszenia drewna, opracowania energooszcz dnych
systemów suszarniczych, ochrony rodowiska zwi zanej z racjonalnym zu yciem
energii, obni enia kosztów zwi zanych z suszeniem, a w konsekwencji poprawy
jako ci produkowanych wyrobów. W odró nieniu do konwencjonalnego procesu
suszenia za pomoc gor cego powietrza, proces suszenia wysokotemperaturowego
(temperatura medium powy ej 100oC) przy wykorzystaniu przegrzanej pary
wodnej lub mieszaniny parowo-gazowej powinien pozwala nie tylko skróci czas
suszenia, ale tak e zachowa w asno ci u ytkowe drewna bez niebezpiecze stwa
utraty dro no ci porów i zwi zanego z tym znacz cego p kania materia u.
Politechnika Gda ska, Katedra Techniki Cieplnej, Wydzia Mechaniczny, Polska
E-mail address:1 [email protected], 2 [email protected]
(Ann. WULS–SGGW, For and Wood Technol. 72 , 2010)
Influence of cutting speed on tool life during of laminated particleboard
drilling
JACEK WILKOWSKI, MICHA DUBIS, PAWE CZARNIAK
Abstract: Influence of cutting speed on tool life during of laminated particleboard drilling. Relationships
between cutting speed and durability of cutting tool was examined in this work. Researches were based on holes
drilling with five tools (diameter 10 mm) made from HSS, in laminated chipboard. Each drill was working with
different cutting speed, while feed per rotation was constant. One of the direct tool wear indicators called
VBmax which shows maximal width of abrasion on clearance face of edge,was chosen. Results revealed that
tool wear drops with increasing of cutting speed. This relationship was assigned in logarythmic scale in order to
estimate Taylor exponent.
Keywords: tool life, drilling, cutting speed, laminated particleboard
INTRODUCTION
Following in course of time process of tool wearing which has the huge consequence in
decreasing of cutting edge properties, is one of the relevant subject in machining science.
Tool wear is a result of its mechanical, thermal, chemical and electrical influence on
machined material. Clearance surface in cutting of wood based materials is the strongest
subjected to this process. There is observed widely abrasion due to existence of hard mineral
contaminations in material, glue, and friction of wood fibers [Pahlitzsh and Sommer 1966].
Wear on rake face is definitely smaller because on this side of edge is shaped only chip
[Porankiewicz 2003]. Raised content of glue and mineral contaminations in outer layers of
wood based materials is a reason of much more intensively edge wearing (even many times)
[Sheikh-Ahmad and McKenzie 1997]. Literature unmistakably states that process of wearing
has not linear character. This relationship shows Lorentz curve. It can be distinguished three
stages of edge wearing. First part, when it comes to run in of the edge has quite violent
course. Next stage of working period of tool correspond to relatively low intensity of wearing
and it is the longest. Tool wear raised quite fast in the latest period of tool life. Exploitation of
the tool is at the time unreasonably since this moment due to very high probability of
catastrophic tool wear or even damage of machine [Dmochowski and Uzarowicz 1984].
Producers of the woodworking tools define their maximal admissible working
parameters. However, these values don’t correspond to optimal values for given machined
material. It concerns cutting speed too. Stefaniak [1970] noticed unexpected increment of tool
wear for cutting speed 50m/s. Porankiewicz [2003] proved according conducted researches,
increasing of tool wearing during milling of chipboards with growth of cutting speed in range
of 19-75m/s. However, Salje et al. [1985] noticed during chipboard milling, certain range (6095m/s) of cutting speed when the speed of tool wear decreases. So literature indicates that
cutting speed significantly influences on durability of edge. User must in this situation search
for compromise between efficiency and constant costs of tool exploitation.
Estimation of cutting speed influence on durability of cutting edges during drilling in
laminated wood based materials was the aim of work. Tool life was expressed by number of
drilled holes. Tool wear indicator which amount 0,7mm, was assumed as tool life criterion.
463
Researches were conducted in Department of Wood Machining WTD SGGW by usage
of working center CNC Busellato JET 130. Five blind drills with center spike and cutters
produced by LEITZ were taken to the experiments. Parameters of the tool were respectively:
diameter of the working part 10mm, length of the working part 80mm, two cutting edges
made from HSS. Optimal cutting parameters for these drills in case of wood base boards
machining according to producer were following: feed speed u=2m/min, rotational speed of
spindle n=4500RPM, cutting speed v=2,36m/s, feed per revolution =0,33mm. Drilling was
carried out in laminated chipboard (three layers) widely used in furniture production, marked
as U511 SM from KRONOPOL firm. Drilling was realized in pieces 1200x350x18mm, 15
holes in each row. Depth of holes amounted 10mm (Fig.1). Experiment consisted of 5 cycles
(one cycle – machining with usage of one tool) for different rotational speeds of spindle (one
tool – one rotational spindle speed) with constant feed per revolution =0,33mm. Tab.1
shows cutting parameters which were used for particular tools.
Fig.1. Schema of piece with cutting direction of successive hole rows
Tab. 1. Cutting parameters for particular tools
Index of tool
Cutting speed: vc [m/s]
Feed speed: u [m/min]
Rotational spindle speed:
n[RPM]
1
1,57
1
2
3,14
2
3
4,71
3
4
6,28
4
5
7,85
5
3000
6000
9000
12000
15000
Laboratory stand to edges wear measurement consisted of digital camera Canon 40D
with matrix which has resolution 10,1mpx, equipped with macro objective Canon 100mm.
Lamps giving constant light with power 80W each (4 pc) were used to take the photos.
Graphical processing of images was made in application GIMP 2.6. The number of pixels
(elementary unit of raster images) which fell on 1mm was fixed by usage of sidle caliper
photo, in order to calibrate analyzed images. Tool wear degree was assessed on base of direct
measurement of VBmax indicator in sight view on clearance face of edge. This value
describes maximal abrasion measured in relation to the corner. Graphical illustration was
showed in Fig.2. The tool was taken away from machine after each series of holes to make
photos and next to amylase digital images. This procedure allowed to asses tool wear
indicator VBmax. Cycles of wearing were conducted till the moment when value of direct
tool wear indicator achieved assumed earlier limit 0,7mm.
464
Fig. 2. Tool wear indicator VBmax
Relationship between number of drilled holes and direct tool wear indicator VBmax
was showed in Fig.3. Mentioned above indicator achieved higher values at higher cutting
speeds. Initially, this relationships fluctuates when the tool runs in (up to 150 holes). It could
be possible that value of VBmax might be lower for higher cutting speeds. This phenomena is
caused by unexpected crumbling of edges what means jumping changes of tool wear indicator
in first stage of tool exploitation.
The relationship between number of holes and cutting speed in linear scale is monotonic
hyperbolical function (Fig.4). This relationship is in logarithmic scale rectilinear (Fig.5).
Value m is called Taylor exponent and corresponds to angle tangent of line established by the
points in logarithmic reference system (Fig.5). In drilling investigations concern laminated
chipboard, Taylor exponent amounted 1,36. Mentioned above relationships are valid only for
certain, fixed in given conditions, range of cutting speed, for this experiment in range
<1,57m/s ; 7,85m/s>.
Fig.3. Curves of tool wear (dependency of indicator VBmax on number of drilled holes), it was
graphically marked criterion of tool wear VBmax=0, 7mm
465
Fig.4. Number of holes made up to limit value of VBmax = 0,7mm for particular cutting
speeds
Fig.5. Dependence of tool life on cutting speed in logarithmic scale
CONCLUSION
Obtained results allow to formulate following conclusions:
1. Growth of cutting speed in range 1,57 m/s do 7,85 m/s make tool life even three times
shorter.
2. With increasing of cutting speed increases the value of direct tool wear indicator
VBmax.
3. With increasing of drilled holes number increases value of direct tool wear indicator
VBmax. This relationship has logarithmic character.
4. Usage of tool life criterion based on direct indicator VBmax is recommended in
scientific researches concern drilling wood based materials.
REFERENCES
1. DMOCHOWSKI J., UZAROWICZ A., 1984: Obróbka skrawaniem i obrabiarki.
Pa stwowe Wydawnictwo Naukowe. Warszawa
2. PAHLITZSH G., SOMMER I., 1966: Einflu der Scheidengeometrie auf
Schneidenabstumpfung, Schnitt-u. Vorschubkraft u. Die gute der Spane. Holz Roh-u.
Werkst. 3:109-117
3. PORANKIEWICZ B., 2003: T pienie si ostrzy i jako przedmiotu obrabianego
w skrawaniu p yt wiórowych. Roczniki Akademii Rolniczej w Poznaniu, Rozprawy
Naukowe, zeszyt 341, Pozna
466
4. SALJE E., DRUCKHAMMER J., STUHMEIER W., 1985: Neue Erkenntnisse beim
Frasen von Spanplatten mit unterschiedlichen Schnittbedingungen. Holz Roh-u.
Werkst. 43: 501-506
5. SHEIKH-AHMED J.Y., McKENZIE W., M., 1997: Measurement of tool wear and
dulling in the machining of particie bard. Proceedings of the 13-th International Wood
Machining Seminar. Vancouver, Canada
6. STEFANIAK W., 1970: Wp yw szybko ci skrawania na t pienie si ostrzy pi
tarczowych z nak adkami z w glików spiekanych przy pi owaniu p yt wiórowych.
Folia For. Pol. B, 9: 66-77
Streszczenie: Wpáyw prĊdkoĞci skrawania na trwaáoĞü ostrza podczas wiercenia páyt
drewnopochodnych laminowanych. W niniejszej pracy zbadano zale no
pomi dzy
pr dko ci skrawania a trwa o ci ostrza skrawaj cego. Badania opiera y si na wierceniu
otworów pi cioma narz dziami ze stali szybkotn cej o rednicy 10mm w p ycie wiórowej
laminowanej. Ka de narz dzie pracowa o z ró n pr dko ci skrawania, posuw na obrót by
wielko ci sta . Analizowano wielko ci wska nika bezpo redniego zu ycia ostrza VBmax
okre laj cego maksymaln szeroko starcia na powierzchni przy o enia ostrza. Uzyskane
wyniki pozwoli y stwierdzi , e trwa o
ostrza maleje wraz ze wzrostem pr dko ci
skrawania. Wyznaczono charakter tej zale no ci z okre leniem warto ci wyk adnika Taylora.
Jacek Wilkowski
Pawe Czarniak
Faculty of Wood Technology SGGW
Wood Mechanical Processing Department
ul. Nowoursynowska 159, 02-776 Warsaw, Poland
Analysis of tool life criterion during laminated chipboard milling
JACEK WILKOWSKI, JANUSZ ZIELI SKI, PAWE CZARNIAK
Abstract: Analysis of tool life criterion during laminated chipboard milling. Direct and technological indicators
of tool wear were examined during climb milling of laminated chipboard produced by three different producers.
Machining was conducted with usage of CNC working center with usage of four tools, perceived in industry
condition as not appropriate to the further work because of insufficient machining quality. Analysis of tool life
criterion based on technological indicator was the aim of the work. Relationships between direct and
technological tool wear indicators proved low and average correlations. Quality of investigated kinds of
chipboards relevantly differentied between each other. Thus, there is no reason to use only one tool life criterion
for wood based boards made by different producers.
Keywords: tool life criterion, mi