Optimized build-up process of film rolls by enhanced

Transcription

Nicht zur Verwendung in Intranet- und Internet-Angeboten sowie elektronischen Verteilern.
Zeitschrift Kunststofftechnik
Journal of Plastics Technology
© 2013 Carl Hanser Verlag, München
www.kunststofftech.com
archivierte, peer-rezensierte Internetzeitschrift des Wissenschaftlichen Arbeitskreises Kunststofftechnik (WAK)
archival, peer-reviewed online Journal of the Scientific Alliance of Polymer Technology
www.kunststofftech.com; www.plasticseng.com
eingereicht/handed in:
angenommen/accepted:
01.03.2013
03.05.2013
Prof. Dr.-Ing. Johannes Wortberg, Dipl.-Ing. Felix A. Heinzler
Institut für Produkt Engineering, Universität Duisburg-Essen
Optimized build-up process of film rolls by
enhanced reversion control
The reversing haul-off unit at today`s blown film extrusion lines is supposed to reduce the
effects of thickness tolerances during the winding process of film rolls. The thickness profile
differences are rearranged along the width of the film roll. Most process setups in the blownfilm-extrusion production do not use the reversion for specific optimization. A new developed
simulation model and programmed tool at the University of Duisburg-Essen shows details to
critical effects of thickness tolerances in the build-up process of film rolls. In correlation with
known winding defects, potentials to optimize the production by a proper reversion control are
shown. The optimization ranges from adjusted speed levels according to the roll diameter to
timed positioning of very critical areas within the roll-changing process and the start of a new
film roll build-up. The optimization potentials are summarized in an enhanced control setup to
connect the extrusion process and the winding for good roll and film quality.
Optimierter Aufbauprozess von Folienwickeln
durch eine erweiterte Reversierungssteuerung
Die negativen Effekte von Dickentoleranzen auf die Qualität von Folienwickeln können
heutzutage durch den reversierenden Abzug reduziert werden. Die Unterschiede im
Dickenprofil der aufzuwickelnden Folie werden über der Rollenbreite reversierend verteilt.
Allerdings werden in vielen Produktionen die Möglichkeiten der Reversierung nicht gezielt
eingesetzt und für eine Optimierung genutzt. Ein neuentwickeltes Simulationsmodell und
Softwaretool der Universität Duisburg-Essen zeigt kritische Effekte des Dickenprofils im
Wickelaufbau und mögliche Optimierungspotentiale zur Steigerung der Wickelqualität. Eine
erweiterte Reversierungssteuerung reicht von einer Anpassung der Reversiergeschwindigkeit
bis hin zu einer gezielte Dickenprofilpositionierung beim Rollenwechsel.
© Carl Hanser Verlag
Zeitschrift Kunststofftechnik / Journal of Plastics Technology 9 (2013) 4
Wortberg, Heinzler
Optimized build-up process of film rolls
Optimized build-up process of film rolls by
enhanced reversion control
J. Wortberg, F. A. Heinzler
Today`s state of the art blown film extrusion lines are equipped with a reversing
haul-off system. The reversing haul-off unit is supposed to reduce the effects of
thickness tolerances during the winding process of film rolls. The reversion
shifts the thickness profile according to the rotation speed of the roll and of
course the reversion speed itself. The thickness profile differences are
rearranged along the width of the film roll during the winding process. Most
process setups in the blown-film-extrusion production have a standardized
reversing speed or do not use the reversion for specific optimization. To adjust
a proper speed or even a speed profile is not taken into consideration to
enhance the roll- and product-quality. A new developed simulation model and
programmed tool at the University of Duisburg-Essen shows details to critical
effects of thickness tolerances in the build-up process of film rolls. In correlation
to known winding defects potentials to optimize the production by a proper
reversion control are shown. The optimization ranges from adjusted speed
levels according to the roll diameter to timed positioning of very critical areas
within the roll-changing process and the start of a new film roll build-up. The
optimization potentials are summarized in an enhanced control setup to connect
the extrusion process and the winding for good roll and film quality.
1
INTRODUCTION
Polymer films have very different applications in today`s everyday life. One
main sector is packaging with a main share of 39,1 % of European plastic
demand in 2011 [1]. Still the primary processed polymers for common
applications are polyethylene (PE-LD, PE-HD, PE-LLD) and polypropylene
(PP). For the different applications, the polymer composition and thickness of
the film varies. It ranges from lightweight food packaging to films for agricultural
use. Whether the film is produced on a cast film line or blown film line, the main
quality indices are the thickness profile of the film and the recommended
arrangement of different material layers. Of course e.g. mechanical or optical
properties are also important with respect to the product requirements. In this
paper the referred process is blown film extrusion. Nevertheless, in addition to
the film properties the thickness profile influences the roll quality during storage
and can cause critical damages. Possible damages are high stress levels
amplified by shrinkage that cause wrinkles or ridges.
Journal of Plastics Technology 9 (2013) 4
161
Wortberg, Heinzler
The predominant influences on the thickness profile during a blown film
extrusion process are the blow head with the extrusion die and the local stretch
ratio considering the cooling of the film. Today´s state of the art film lines enable
a good process control and stability during the processing of up to 12 layer
films. But still current thickness profiles have a tolerance band that has to be
dealt with in the processing. To lower effects of the thickness profile and to
prevent defects, blown film extrusion machines are equipped with a reversion or
rotation system [2]. To show influences of the thickness profile arrangements, a
tool for model based process prediction and enhancement has been developed
at the University of Duisburg-Essen. In the following the setup of the model, the
calculation bases and possible optimizations for the processing are shown in
correlation to winding defects.
2
THICKNESS PROFILES IN BLOWN FILM EXTRUSION
Within the blown film extrusion process, the polymer melt is conveyed through a
film blowing die. In the following process steps the polymer melt will be
stretched to reduce thickness and to orientate the polymer chains bidirectional.
This important step increases the mechanical properties of the produced film.
During this process step, the remaining thickness profile of the film can be
assigned to unequal flow resistances within the feeding system and film die,
deposits at the die or an inaccurate centering of the blow head. After the
extrusion process these differences are amplified by the cooling because of the
different local stretch ratios or different local cooling air streams. Along the
circumference of the bubble, local varying thickness is quick-frozen after
crossing the frost-line. Even if “the single most important objective for any blown
film extrusion operation is to produce film that meets thickness specification” [3]
today’s high quality multi-layer films have a thickness profile that can cause
critical damage if wound-up on the film roll. As the thickness profile is fixed after
crossing the frostline, on the one hand a very precise profile with low tolerances
has to be achieved, on the other hand the following process steps have to deal
with this profile to prevent damaged rolls. With a good process control and
thickness measuring systems, today the local cooling of the bubble is influenced
to change the local thickness by different cooling rates and stretch ratios. By the
reversing haul-off system the fixed thickness profile is shifted along the width of
the roll to prevent winding defects.
To reduce the effects of wound-in thickness profiles and to prevent gauge
bands, plastic deformation or drag down, the modern blown film lines have an
integrated reversion. There are several different possibilities for a reversion or
rotation-system at a blown film extrusion machine. Today’s state of the art is a
draw-up with a reversion integrated in the angle bar system. Nevertheless, all
reversing or rotating machine parts between the extrusion line and draw-up aim
to shift thickness profiles before the winding process.
162
Within an average film production, blown film lines have got a reversing draw-up
which is set to a standard speed. The adjusted speed depends on polymer
materials, bubble layers and flexibility of the produced film. If a stable process
without any wrinkles in the draw-up is adjusted, the reversion speed will remain
at the first setting. The reversion reduces the described critical effects of the
thickness profile to roll quality. A certain statement to the range of this effect
caused by reversion speed variation cannot be made so far.
In the following figure the thickness of a five layer PE-EVOH film with a length of
4500 m is shown. The film has a layer thickness of ~52 μm. The thickness was
measured after the production process by unwinding the film, that is why the
effect of the reversion is displayed by the shifted thickness profile.
Film thickness [μm]
Wortberg, Heinzler
Figure 1:
Thickness profile arrangement on a film roll
According to [4] and as seen in the figure, a film extrusion die line tends to
produce “a thick caliper area that runs the entire length of a roll or for that
matter an entire work shift” [4]. This caliper areas are shifted by the reversion
but only very slowly. In a common production there are 3-5 reversion runs on
5000 m wound-up film. So the layers stored on the roll still do not compensate
the thickness differences by the shifted profiles. The figure shows for example
that areas with a high profile are still stored mainly on the right side of the roll.
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Wortberg, Heinzler
The effect of the reversion is very small. This is a critical area for winding
defects. If the minimized thickness profile is stored on a roll of about 10.000 m
of film, cumulated tolerances multiply profile differences. Some winding defects
related to this effect are described in the following.
During the winding process, a certain amount of air is wound-in between the
different layers of film. This veils the overlapping profiles and their addition
during the process. After the roll is finished with the required web meters, the
“living” film shrinks and the air amount between the layers diminishes. Entrained
air is needed to compensate wound in stress and shrink. The effects of the
resulting stress can be amplified through a critical setup of the thickness profile
and veiled by the wound-in air. When wound-in air is pressed out of the roll by
increasing stress and shrink, the thickness profiles have no buffer any longer
and areas with a strong positive profile add up. Gauge bands or areas with
increased hardness occur.
3
WINDING DEFECTS
During the winding process a local larger roll diameter is build up through the
reinforcement of the thickness caliper. These gauge bands can damage the film
and cause problems during further processing. Even though not every diameter
difference can be seen from outside the roll, especially local high tension
caused by small diameter differences and unequal shrink lead to critical defects
inside the roll. Wound-in stress is amplified by shrinkage during the storage. On
the one hand shrinkage is mass-dependent and areas with local arranged high
thickness profiles have a different shrinkage behavior than areas with lower
profiles. On the other hand the remaining air between the film layers is pressed
out of areas with larger diameters and the layers get into direct contact during
the shrink process after the production. This leads to areas with high stress and
high roll hardness. Examples for these defects are shown in the following figure.
As the roll needs a level of wound-in tension to be stable, a local tension peak
will result in a higher stretch level. When the roll is used for further processing,
the film that is locally more stretched will cause drag down or shows plastic
deformations. Some winding defects are shown as examples in figure 2.
Figure 2:
Different winding defects
164
Wortberg, Heinzler
These critical areas cannot be seen from outside the roll and the damaged
layers occur during further processing. To correlate the shown defects, the
process conditions and the film thickness parameters, a new model based
optimization tool was developed at the University of Duisburg-Essen. To identify
optimizations for process parameters and process control, the algorithm and
setup of the calculation bases will be discussed in the following.
4
MODEL BASED CALCULATION SETUP
The analysis focuses on a longitudinal cut along the width of the roll in cross
direction (CD). Within this view, an addition of layers can directly be shown as
progress or diagram for every new layer. With the given start setup some
mandatory factors have to be calculated. The prognostic tool is based on
geometric correlations. Therefore some simplifications and assumptions have to
be set to reduce complexity of the winding process of blown film to a
manageable prognostic model. The thickness profile of the film will be treated
as thickness information spots according to the measuring accuracy. To
increase the calculation accuracy, it is possible to approximate the thickness
profile with additional calculation spots between the measured values as a
spline function. This is important to realize the reversion effect at low roll
diameters and high rotation speeds. In a second step the winding process is
reduced from an Archimedean spiral to a layer based system. The build-up
process is seen as adding new layers above the one before. Every layer nx is
seen as a closed ring as shown in figure 3. Nevertheless, the constant influence
of the reversion system during the build-up process will be considered and
calculated as a shift factor for every information spot continuously.
Figure 3:
Layer System of the Prognostic Model
165
Within the analysis of the winding process and through the described
assumptions, every local thickness spot can be described as a line being
transported from the extrusion die to the winder. Between these processes,
extrusion, winding and storage on the roll, the lines are shifted along the width
of the film. The following figure shows the reduced setup of the model with the
winding process. The distance between measurement of the thickness profile
and winder is constant. Therefore, the time difference between measurement of
the thickness profile and winding process can be ignored. As an example, the
line of one measurement spot being shifted and transferred to the roll is
outlined. Of course the outlined transportation way of one spot along the film
width is reliant to the setup of the reversion system. This point and possible
improvements will be discussed in the following.
Wortberg, Heinzler
Figure 4:
5
Layout of the prognostic Model
CALCULATION BASES
The given thickness profile leads to the average thickness as a mean value.
This factor is important for non-local effects within the build-up process such as
the average radius ra or diameter da of the roll. The average radius is calculated
via an equitation depending on the core diameter and an addition of the layers
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Wortberg, Heinzler
with average thickness hm per process time Ns(t). By using the average radius,
the time of circulation can by calculated. It does not base on local effects which
would falsify the results as the production speed is to be seen as constant.
Tcir (t ) = 2 ⋅ π ⋅
ra (t )
vb
(1)
The time of circulation Tcir is important for the build-up process and the constant
speed of the film web. As the first prognostic model will not consider elastic
stretch and wound in stress as a result of different local radii, speed differences
cannot be allowed within the calculation. Conversely, when a difference in the
diameter is located through the analysis, it indicates the critical areas as
mentioned before. Higher stress levels can result in defects of the roll and film
web indicated by the local layer setup.
A good measurement of the thickness profile results in a good prognostic of the
profile positioning during the process. By using a shift factor W d, the model
calculates whether the profile is shifted at least one thickness block during one
rotation of the winder or not. With a high accuracy and approximated splines
between the measured values, even small shifts at the start of the process can
be calculated. In a first step, the range of the shifting for every measurement
point over the circumference has to be calculated through the following
equation.
Wd (t ) = Tcir (t ) ⋅ vrev
(2)
This equation contains the range of the shifting W d depending on the process
time t. The circulation time Tcir increases during the process. For every new
layer Tcir has to be recalculated. By increasing the diameter of the roll, the
influence of the reversion increases too. The model only prognosticates the
build-up process for a cut along the roll width. Therefore, the shift factor is
always calculated for the outer line or the last layer. If the range of shifting is not
within the measurement steps, there has to be a curve fitting to decide if a
profile block is shifted from one to the next layer or not. This underlines why
good measurement accuracy is important to increase the prognostic reliability.
Figure 5:
Shift factor to calculate the reversion effect
167
For the last layers, when the shift factor increases to a lot more than 10 blocks,
accuracy is no longer mandatory. To reproduce the build-up of the first layers,
where only a small shifting takes place, a measurement with very few blind
spots is needed to show the small shifting of the profile during the short rotation
times of the winder. Within a last step, for every layer and every measurement
point, the direction of rotation has to be considered.
6
PROCESS SETUP WITHIN THE CALCULATION MODEL
The setup of the tool is very flexible and can be adjusted to the process
conditions. The main influencing variables to be adjusted at the start are:
measured thickness profile along 360 ° circumference as a matrix with the
number of approximated calculation steps, width of the roll b [mm], winding
speed or production speed vb [m/min] and the core diameter r0 [mm]. It can be
decided if the film shall be treated as a web or tube.
angle [°]
The reversion speed vrev has to be set as a profile of time and rotation angle.
For reproducing the build-up process of standard productions, a constant profile
would be sufficient. For the integration of improvements, profiles as shown in
comparison in the following figure are required.
angle [°]
Wortberg, Heinzler
time [min]
Figure 6:
time [min]
Reversion profile setups
With increasing time of circulation, the shift of defined thickness profile blocks
by reversion can be determined. If you consider one block of the thickness
profile being shifted by the reversion, this would result in a time based
oscillation of this block over the width of the film web or the rolls. Through
different rotation times of the winder the reversion has an increasing effect on
the build-up process, since as the oscillation time of the thickness blocks is
constant according to the reversion speed.
168
The thickness profile is imported as a .csv-data. According to the production, an
updated profile can be set for different measurement points during the
calculation. So it is possible to e.g. update the profile every 1000 m of produced
film. As output, a direct figure with the layer setup on the roll is displayed as
total profile along the width of the roll or relative profile to the median profile
diameter. For detailed views, the calculated results can be exported and the
scaling of the figure is adjustable.
7
INFLUENCES AT THE START OF THE WINDING
PROCESS
At the start of the winding process, new layers are added to the roll very fast.
Low reversion speeds will have a very minor effect on the positioning within this
state of the process. For the worst case, the layers will be wound-up without a
shift of the thickness profile. Especially at the start of the process and the first
layers this is very critical. In the following, this part of the roll will have the
highest tension by shrink and process setup. So if in this part the profile
maximal are stored directly above each other, defects by high stress levels can
occur very easy. Investigations of the areas within the rolls, where defects occur
most, have shown that on the one hand the sides of a roll and the other hand
first layers are critical. At the sides of a roll of i.e. a contact winder system the
pressure application is directly passed to the roll. In the middle of the roll, the
pressure application and therefore wound-in stress is reduced because of the
deflection of the contact roll axle. Possible improvements with these boundary
conditions will be discussed with an production example. The thickness profile
used for the calculation was randomly measured at a industrial blown film
extrusion line for packaging films.
thickness profile [mm]
Wortberg, Heinzler
film width [mm]
Figure 7:
Example of a film thickness profile in a production (measured)
For a better comparison of the following relative roll diameter, the mean roll
diameter for some web meters wound on a roll are shown in table 1.
169
Web Meter
Mean Roll Diameter
500 m
~170 mm
1000 m
~200 mm
2000 m
~374 mm
3000 m
~506 mm
Table 1: Mean roll diameter for different wound up web meters
To show the described effects of the reversion speed on the first layers, the film
profile as shown in figure 1 is used for the calculation. The profile maximum is
shifted slowly during the process from left to right on the roll and backwards.
Figure 7 shows the thickness profile for the calculation. The process conditions
are width of the roll 1200 mm, production speed 200 m/min and a constant
reversion speed of 6 min/360 °. The used core diameter was set to standard 3 ”
cores. Of course, a larger core diameter would increase the effect of the
reversion at the start of the winding process, however in the following this setup
will be seen as fixed production standards.
angle [°]
Final Layer 100m
time [min]
relative diameter [‰]
Wortberg, Heinzler
roll width [mm]
Figure 8:
Relative thickness profile for the first 100 m on a film roll
In figure 8, the relative roll profile for the first 100 m wound-up film is shown for
every 100th layer. As shown in the picture, the first layers are added to the roll
with nearly no influence of the reversion. So the thickness profile builds up local
differences that can lead to high stress levels. Unfortunately, the main peaks of
the profile are stored at the edges of the roll, where the applied pressure is at its
maximum. If the first 1000 m and every 500th layer is considered, a slow effect
of the reversing haul-off system levels the totalized roll profile. Nevertheless, the
roll profile that is build-up with the first web meters cannot be compensated by
170
the shifting in the following wound-up web meter. As a result there remains a
maximum on the left side and a low profile on the right side.
angle [°]
Final Layer 1000m
time [min]
Wortberg, Heinzler
roll width [mm]
Figure 9:
Relative thickness profile for the first 1000 m
Even in the following production process, there will still remain the influence of
the start of the winding process. The following web meters will be wound on
much less layers because of the increasing roll diameter. The effect and shifting
of the reversion will adjust the thickness profile much better to the roll, but the
first 1000-2000 m to the core will mainly be influenced by the direct totalized
thickness profile of the film. This far air entrainment and air buffer between the
layers are not considered. In a real process, this buffer would compensate a
small part of the effects. Nevertheless, the air buffer will be pressed aside at the
critical areas and result in a direct contact of the layers. As an interpretation of
the results it can be assumed that not every maximum will result in a gauge
band. But there will be different hardness levels and the areas with high local
amplitudes will result in critical stress.
To increase the roll quality and to reduce critical areas within the roll, the first
possibility is to increase the reversion speed. The higher speed will shift the
profile faster and will have a larger influence on the first wound-up layers.
Because of the high rotation speed of the winder and therefore the fast build-up
of the first 1000 layers, will be effected by the reversion limited. At a production
speed of 200 m/min the first 1000 layers are built up within 6 min with
exponential tendencies for the following layers. So the effect of the higher shift
rate will have a positive effect but not compensate the defects in the first web
meters. In most production processes, the maximum speed is limited by the film
material composition and the machine properties. It has to be prevented that the
whole bubble is shifted during the extrusion process and turned out of the die.
That would influence the process stability. Other effects are wrinkles on the film
during the haul-off process. It can be said that the reversion speed is a limited
but important process parameter. At the start of the winding process the high
171
Wortberg, Heinzler
rotation speed recommends the maximum reversion speed to adjust the film
profile on the roll properly. Limited by the described process requirements and
fixed process setup for the thickness profile and a maximum production speed,
advanced process control is necessary to reduce possible defects.
Because of the continuously increased roll diameter during the winding process,
the reversion affects the adjustment of the thickness profile with increasing
influence. Unfortunately, the outer layers and last web meter of the roll are not
critical in reference to the described defects. That implements possible improvements to prevent winding defects by compensating the bad adjusted thickness
profile within the first layers and web meters.
8
ENHANCED PROCESS QUALITY BY OPTIMIZED
REVERSION CONTROL
The described investigations to winding defects have shown that the defect
occurrence at the edge of a roll is much higher than in the middle. That can be
explained by the deflection of the contact roll and therefore the lower wound-in
tension or pressure in this area. The remaining air buffer is higher and can
compensate local tension and shrink. The first improvement to reduce the
defect occurrence, if the film profile and production process is considered as
fixed, is to prepare the start of a new roll during the last web meters of the
previous roll. The last web meters of a roll can be used to adjust the critical high
local thickness profile to the middle of the roll at the start of a new winding
process. The large diameter of film rolls at the end of a winding process enables
a very precise positioning without reducing the roll quality or disturbing the
production process. For the new roll an optimized setup to reduce the tension in
critical areas is configured. With the proper adjustment, the reversion speed is
at its process-depended maximum and local thickness peaks are located at the
middle of the roll width.
An example is shown in the following figure. The film profile is identical to the
one of the previous example but the positioning on the roll is adjusted. The
resulting maximums are setup in the middle of the roll width to reduce the defect
possibility.
172
angle [°]
Final Layer 1000m
time [min]
Wortberg, Heinzler
roll width [mm]
Figure 10:
Relative thickness profile with adjusted maximum position
The second improvement is an adaption of the reversion direction to the actual
roll thickness profile. Because of the servo drive that powers the reversing hauloff it is possible to change the rotation direction as fast as the film bubble
remains stable. It is not necessary to turn the haul-off system 360 ° until the
rotation direction is changed. By an advanced process control, the rotation
direction and speed can be adjusted to optimize the resulting roll thickness
profile. It is important to prevent areas with high local amplitudes which result in
high tension peaks and winding defects. This improvement cannot influence the
first 1000 web meters because of the high winding speed and small roll
diameter. By a continuous calculation and direct control of the reversion, the
film profile can be used to even the differences during the following build-up
process. Of course a random effect to even the profile occurs with normal
reversion setups, however this effect can be mandatorily improved by a direct
control. This directly increases the roll quality and reduces critical local tension
peaks.
To show this effect, an example calculation with just a small change in the
reversion profile is shown in figure 11. The reversing haul-off does not rotate
360° but follows the profile and changes the rotation direction at 180 ° again. Of
course, the first layers are not influenced by the setup but as shown in the
figure, the effect starts at layer 2000 where the difference is reduced from a
maximum of more than 6 ‰ to less about 5,6 ‰. The main effect can be seen
in the following 2000 m added to the roll. Because of the optimized reversion
profile, the total thickness profile on the roll is equalized and will reduce the
tension differences. This small improvement shows the potential of a direct
reversion control to optimize the total roll thickness profile linked to the actual
extrusion process.
173
angle [°]
Final Layer 3000m
time [min]
Wortberg, Heinzler
roll width [mm]
Figure 11:
Relative thickness profile with adjusted maximum position
and reversion profile
As the reversion speed is limited to the process properties and produced film,
the reaction time of this control system is limited too. To enhance the roll quality
further on, the cooling of the bubble has to be integrated into the control chain.
Today, the film profile can be influenced by the cooling system to adjust a better
thickness profile. If the local peaks are overcompensated, a local maximum will
be followed by a local minimum in the same area. If the reversion cannot react
fast enough to even the roll profile, this is another possibility to secure proper
film roll quality. In the simulation, this can be integrated by an update of the
used thickness profile for the calculation.
9
DISCUSSION AND CONCLUSIONS
Reasons for roll defects depend on very different factors. Even the described
influence of the reversion is only one part and cannot be seen as a single task.
It is a combination of the cooling, the quality of the die and the maintenance of
the extrusion line and the accurate setup of the winding parameters for the
product. The described tool can display influences between the resulting
thickness profile in the extrusion- and cooling process and the winding setup.
The prognostic of the build-up process indicates critical areas and optimization
potentials. Still, this is no automated process, but the machine operator gets
another indication to optimize the machine parameters for production. In
combination with hardness measurement, existing defects can be analyzed and
solved with a calculation for different reversion setups.
Even though the tool does not consider influences of air entrainment, the results
indicate the critical process areas and show effects of parameter variations. To
174
Wortberg, Heinzler
consider thickness profile positioning within the process by adjusting the cooling
process, new profiles can be read in to be considered in the calculation. By this
a direct integration would be possible. First results within the research project
underline the important role of the thickness profile positioning within the
winding process. To prevent defects, it is important that thickness profile
spreading has to be compensated on the roll. Otherwise, the error probability
increases. The developed tool does not automatically solve this problem but
shows optimization potentials if defects occur within the production and a
possibility to setup a control chain for enhanced roll quality. It is recommended
that the possibility to optimize the start process for new rolls, is integrated into
today’s blown film line control. In addition, the calculation and online
optimization to control the reversion profile for an optimized thickness profile on
the film roll has to be integrated as a new process control option.
Acknowledgements
This project is supported by
ERDF – European Regional Development Fund
„Investition in unsere Zukunft“
NRW Ziel-2 Program
CheK.NRW – Chemie und Kunststofftechnik
Title: Maßnahmen zur Erhöhung der Rohstoffeffizienz bei der
Kunststofffolienherstellung
In cooperation with:
Windmöller & Hölscher KG (Lengerich, Germany);
Kobusch Sengewald GmbH (Halle/Westfl., Germany)
175
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PlasticsEurope
An analysis of European plastics production, demand
and waste data for 2011
PlasticsEurope Market Research Group, 2012
[2]
[3]
Wortberg, J.;
Saul, K.
Potentials of energy-efficiency film-extrusion
Cantor, K.
Blown Film Extrusion
Packaging Films, 2011
Carl Hanser, München, p. 126, 2006
[4]
[5]
Good, J. ;
Roisum, D.
Winding- Machines, mechanics and measurement
Heinzler, F.A;
Wortberg, J
Thickness profile effects on the build-up process of
film rolls
Lancaster, DEStech Publications, 2008
Society of Plastics Engineering Annual Technical
Conference (SPE Antec), 02.04.-04.04.2012,
Orlando (USA)
Keywords:
reversion, haul-off, winding defects, optimized process control, roll quality
Stichworte:
Reversion, Folienabzug, Wickeldefekte, optimierte Prozesskontrolle,
Rollenqualität
Wortberg, Heinzler
176
Autor/author:
Dipl.-Ing. Felix A. Heinzler
Prof. Dr.-Ing. Johannes Wortberg
Universität Duisburg-Essen
Institut für Produkt Engineering
Lotharstr. 1
47057 Duisburg
Herausgeber/Editor:
Europa/Europe
Prof. Dr.-Ing. Dr. h.c. Gottfried W. Ehrenstein, verantwortlich
Lehrstuhl für Kunststofftechnik
Universität Erlangen-Nürnberg
Am Weichselgarten 9
91058 Erlangen
Deutschland
Phone: +49/(0)9131/85 - 29703
Fax.:
+49/(0)9131/85 - 29709
E-Mail-Adresse: [email protected]
Verlag/Publisher:
Carl-Hanser-Verlag
Jürgen Harth
Ltg. Online-Services & E-Commerce,
Fachbuchanzeigen und Elektronische Lizenzen
Kolbergerstrasse 22
81679 Muenchen
Tel.: 089/99 830 - 300
Fax: 089/99 830 - 156
E-mail-Adresse: [email protected]
E-Mail-Adresse:
[email protected]
Webseite: www.uni-due.de/kkm
Tel.: +49(0) 203 279 3280
Fax: +49(0) 0203 379-4379
Amerika/The Americas
Prof. Prof. h.c Dr. Tim A. Osswald,
responsible
Polymer Engineering Center,
Director
University of Wisconsin-Madison
1513 University Avenue
Madison, WI 53706
USA
Phone: +1/608 263 9538
Fax.:
+1/608 265 2316
E-Mail-Adresse:
[email protected]
Beirat/Editorial Board:
Professoren des Wissenschaftlichen
Arbeitskreises Kunststofftechnik/
Professors of the Scientific Alliance
of Polymer Technology
Wortberg, Heinzler
177

Optimized build-up process of film rolls by enhanced

Transcription

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