22/3214 version pdf

5
Introduction
7
9
Outstanding Attributes
List of Grades
11
Low Wear, Low Friction Series
13
Key Properties Table
17
Delrin
®
Acetal resins
Performance
Stiffness & Strength
19
Creep Resistance
21
Stress Relaxation
23
Fatigue Resistance
25
Impact Resistance
27
UV Resistance
29
Temperature
31
Chemical Resistance
33
37
Typical Applications
Design
with
Delrin
Design Basics
®
® DuPont’s registered trademark
▲
▲
▲
Start
with DuPont
Engineering Polymers
Radii
39
Uniform Wall Thickness
41
Ribs
43
Bosses
45
Threads
47
Snap Fits
49
Rapid Prototyping
51
Stockists/Machinists
53
Colours
55
Processing
57
Regrind & Recycling
59
Laser Marking
61
Medical Applications
63
Further Reading
65
▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲
Do You Speak Delrin®?
‘Design with Delrin ’
Data at your fingertips
®
®
resins
Acetal
®
?
9
k Delrin
u Spea
Do Yo
11
tion
uc
od
Intr
ributes
tt
A
13
anding
Outst
s
17
s
Grade
n Serie
List of
tio
ic
w Fr
19
ear, Lo
th
Low W
Streng
ble
&
Ta
s
ss
21
Stiffne
opertie
e
Key Pr
sistanc
Re
23
ep
Cre
n
tio
xa
Rela
25
Stress
tance
sis
Re
27
Fatigue
e
sistanc
Re
29
ct
Impa
e
ance
sistanc
31
Perform
UV Re
re
tu
ra
33
Tempe
nce
Resista
al
ic
37
Chem
ngth
& Stre
ations
l Applic
Typica
Radii
s
icknes
Wall Th
Uniform
Ribs
Design
with
Delrin
®
t’s
® DuPon
emark
red trad
registe
▲
▲
▲
Start
uPont
with D
ymers
ring Pol
Enginee
Basics
Design
Bosses
s
Thread
ts
Snap Fi
yping
Protot
Rapid
hinists
sts/Mac
Stocki
rs
Colou
sing
Proces
cycling
d & Re
Regrin
ng
Marki
Laser
ns
licatio
al App
Medic
ing
r Read
he
rt
Fu
es
Sampl
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5
7
Delrin
5
7
9
11
13
17
19
21
39
41
43
45
47
49
51
53
55
57
59
61
63
65
Use the colour
coded bars to help
you ‘flick’ through to
the relevant section
and data
‘Design with Delrin®’
This handbook makes basic
information easily available to
designers and others and gives
a quick reminder of the
impressive range of Delrin®
properties.
It is illustrated with a selection
of photographs showing some
of the enormous variety of
applications for which Delrin®
has already been successfully
used.
4
5
Do You Speak Delrin®?
Back to index
lications
View app this binder
ut
througho
. . . This Delrin® “phrase book”
will help you brush up on
your acetal knowledge until it
becomes your first language.
Delrin® versatility: snap fits to ski bindings, clips to conveyors,
buckles to bicycle parts
This publication is also available at
http://www.dupont.com/enggpolymers/europe
▲
. . . Do you know where
Delrin® is used – and why?
Have you heard of Delrin®
but don’t know what it feels
like?
ules
simple r ® in
e
s
u
–
s
r
Delrin
Designe
est from
b
e
h
t
t
e
to g
Basics”
“Design
▲
. . . Are you up to speed with
all the new grades including
Low Wear, Low Friction, UV
Resistant and the Eleven
Series?
lend of
unique b them in
a
s
a
h
Delrin
rstand
s – unde
propertie ce”
an
“Perform
®
▲
. . . Do you speak Delrin ?
Are you as fluent as you
would like to be?
®
6
7
INTRODUCTION
What is Delrin®?
the automotive, appliance,
construction, hardware, electronics
and consumer goods industries.
Delrin is an engineering
thermoplastic with a combination of
physical properties not available
either in metals or other plastics.
Trade name: Delrin®
Generic name: acetal
Sub class: homopolymer
®
Back to index
It has a well balanced profile of
mechanical properties, environmental
resistance and processability at
moderate cost.
Delrin® acetal resins provide
substantial strength, stiffness and
creep resistance.
Abbreviation: POM
(polyoxymethylene)
Structure: highly crystalline
polymerized formaldehyde
Typical examples of Delrin® applications
appear throughout this handbook
Delrin® has gained widespread
recognition for reliability of
performance in many thousands of
engineering components all over
the world.
Since its commercial introduction by
DuPont in 1960 it has been used in
Delrin® acetal homopolymer was introduced by DuPont in 1960.
Copolymer acetal followed somewhat later, around 1962.
Delrin® versatility: skate parts, ski bindings, speaker grilles
8
O U T S T A N D I N G AT T R I B U T E S
The outstanding attributes
of Delrin® acetal resins include:
Back to index
Toughness at low temperatures
(down to –40°C)
High mechanical strength
and rigidity
Natural lubricity
Fatigue endurance unmatched
by other plastics
Resilience
High resistance to repeated
impacts
Good electrical insulating
characteristics
Excellent resistance to
moisture, petrol, solvents etc.
Ease of fabrication
Excellent dimensional
stability
Wide useful temperature range
(in air –50 to +90°C with
intermittent use up to 160°C
This unique balance of properties makes Delrin® suitable
for many metal replacement projects
Delrin® versatility: coloured lighters to carousels, pumps to pegs
9
LIST OF DELRIN® GRADES
10
Standard
100 High viscosity
100P High viscosity, easy processing.
111P High viscosity, easy processing,
improved stability
Back to index
500 Medium viscosity
500P Medium viscosity, easy processing
511P Medium viscosity, easy
processing, improved stability
900P Low viscosity, easy processing
911P Low viscosity, easy processing,
improved stability
1700P Very low viscosity, easy
processing, improved stability
UV
127UV
527UV
927UV
1727UV
107
507
High viscosity, best UV
Medium viscosity, best UV
Low viscosity, best UV
Very low viscosity, best UV
High viscosity, UV
Medium viscosity, UV
Low Wear/Low Friction
DE 9156
120MP
DE 9152
520MP
500AF
500CL
500AL
900SP
500SC
100KM
1,5% PTFE micropowder
20% PTFE micropowder
1,5% PTFE micropowder
20% PTFE micropowder
20% PTFE fibres
Chemical Lubricant
Advanced Lubricant
Special Polymer
Silicone Concentrate
Kevlar® Modified
Toughened
100ST Super tough, high viscosity
100T Toughened, high viscosity
500T Toughened, medium viscosity
Glass Reinforced/Filled
510GR
525GR
570
577
10%GR
25%GR
20%GF
20%GF, UV resistant
Delrin® 100 = high viscosity 500 = medium viscosity 900 =low viscosity
Delrin®: whether standard or specialised, a grade for
every application
11
RESIN SELECTOR – DELRIN® AGAINST METAL
Level 1
Tribological system
Level 3
Solution: appropriate
grade of Delrin®
Delrin® with low specific wear rate, w· s
Wear Delrin® 100/500/900
high PV
wear
steel
Delrin® 500CL
Delrin® DE9152/DE9156
Delrin® 500AL
Delrin® 100KM
Delrin® 520MP
®
Best Delrin 500AF
($)
($$)
($$)
($$)
($$$)
($$$)
($$$$)
Delrin® with low specific wear rate, w· s
Wear
low PV
Delrin®
against
metal
Best
Delrin® 100/500/900
Delrin® DE9156/DE9152
Delrin® 500CL
Delrin® 500AL
Delrin® 100KM
Delrin® 520MP
Delrin® 500AF
($)
($$)
($$)
($$)
($$$)
($$$)
($$$$)
Delrin® with low coefficient of friction, µ
Friction Delrin® 100KM
friction
($$$)
Delrin® 100/500/900
($)
Delrin® DE9152/DE9156 ($$)
Delrin® 500CL
($$)
Delrin® 500MP
($$$)
®
Delrin 500AL
($$)
®
($$$$)
Best Delrin 500AF
High wear resistance
against aluminium
aluminium
wear
PV= pressure • velocity
Delrin® 100KM
Delrin® 500CL
Delrin® 500AL
Back to index
LOW WEAR, LOW FRICTION SERIES
THE FACTORS A
FFECTING
WEAR AND
®
FRICTION A
Choosing Delrin is a good
RE:
Pr
es
su
*
re
starting point for applications in
of contac
* Relative velocity t
which wear and friction are major
* Temperature
®
Geometry of
*
issues. Unmodified Delrin has
m
Frequency of otion
*
m
oti
low friction and wear against steel
* Nature and finish oofn
surface
as can be seen from the chart
Lubrication
*
below.
($$$)
($$)
($$)
($) . . . . ($$$$) = relative cost
PROTOTYPE
1000
Specific wear rate
(10-6 mm3/Nm)
12
Level 2
Requirements:
how can I avoid...?
!
ew
N
ABS
Countersurface
= steel
100
TESTING IS IMPORTANT
▲
PPO▲
PBT▲
▲ PA66
POM ▲
10
(Delrin®)
▲POM+20%PTFE
1
0.00
(Delrin®)
0.10
0.20
0.30
0.40
For metal as a
counter surface,
the harder the
surface the
better the
wear and
friction behaviour
of the system.
Aim for a hardness
of greater than
50 HRc
Dynamic coefficient of friction, µ
The natural lubricity of Delrin® means it may be found unlubricated
in many gear and bearing applications
13
RESIN SELECTOR – DELRIN® AGAINST DELRIN®
Level 1
Tribological
system
Delrin®
against
Delrin®
Level 3
Solution: appropriate
grade of Delrin®
Level 2
How can I
avoid...?
Non-squeaking grades of Delrin®
Delrin® 500SC@10%
($)
Delrin® 500AL
($$)
Delrin® 900SP
($$)
Delrin® 120MP/520MP
($$$)
Delrin® 500AF
($$$$)
squeak
wear
Delrin® with low specific wear
Wear Delrin® DE9156/DE9152
Delrin® 500SC @ 5%
Delrin® 500AF
Delrin® 500AL
Delrin® 900SP
Delrin® 500SC @ 10%
®
Best Delrin 120MP/520MP
rate, w· s
($$)
($)
($$$$)
($$)
($$)
($)
($$$)
external lubrication
other material for
counter surface
reduce pressure
external lubrication
Back to index
situation it is normal to choose
dissimilar materials (eg Delrin® acetal
and Zytel® nylon). Factors such as
dimensional stability may make such a
choice impossible, in which case the
new Low Wear, Low Friction grades
of Delrin® may be suitable. The table
below shows the improvement in
wear and friction compared to
standard grades.
Friction
friction
Best
impact
noise or
failure
Delrin® DE9156/DE9152
Delrin® 500AF
Delrin® 520MP
Delrin® 120MP
Delrin® 500AL
Delrin® 500SC @ 5%
Delrin® 900SP
Delrin® 500SC @ 10%
($$)
($$$$
($$$)
($$$)
($$)
($)
($$)
($)
New Grades
external lubrication
Delrin® toughened grades
(external lubrication needed)
Delrin 100T
Delrin® 500T
Delrin® 100ST
®
($)
($)
($$)
($) . . . . ($$$$) = relative cost
tain grades
(squeak) dram reduce noise
atically
with standard compared
grades
10000
Delrin® with low coefficient of friction, µ
Specific wear rate
(10-6 mm3/Nm)
14
LOW WEAR, LOW FRICTION SERIES
. . . continued
Quieter too!
Cer
When two parts are in contact in a wear
Level 4
Solution: other
than material
choice
1000
Standard
Grades
100
●900SP
10
●500AL
●520MP
Countersurface
= Delrin®
1
0.10
optimise design
100P●
DE 9152●
0.20
0.30
Dynamic coefficient of friction, µ
Please refer to the grades list for details of
Low Wear, Low Friction Resins
0.40
15
K E Y P R O P E RT I E S TA B L E
Based on Delrin® 100 high viscosity acetal
16
Property
Back to index
Units
Value
Yield stress
MPa
71
Yield strain
%
25
Strain at break
%
70
Flexural modulus
MPa
2800
Izod notched impact
strength @ 23°C
@–40°C
kJ/m2
12
8
Temperature of
°
deflection under load
C
115
Melt temperature
°C
177
Flammability
HB
Shrinkage
1,9 to 2,2
%
Melt Flow Index
2,2
g/10 min
Chemical Resistance
outstanding
3
Density
1,42
g/cm
17
Fo
r
see grap
sec nex hs
tio t
n
Ca
dis mpu
ava kett s
ilab e
le
Delrin® 100 is the toughest unmodified acetal available
with a unique combination of elongation and stiffness
Delrin®: stiff, strong, tough, chemically resistant
Description/Application
Snap fit buckle
PERFORMANCE
Stiffness and Strength
Young’s modulus (GPa)
Back to index
The modulus of Delrin® is
affected by changes in the
temperature as shown
below.
19
80
-20°C
23°C
60
Stress (MPa)
18
3
2
40
90°C
20
0
1
0
2
4
6
8
0
—20
0
20
40
60
Temperature (°C)
Young’s modulus of Delrin®
as a function of temperature
80
100
Stress v Strain at –20°C,
23°C and 90°C
The mechanical
response to short term loads
is shown above
To judge the stiffness and springiness of Delrin® ask your nearest
DuPont Engineering Polymers office for test bar samples.
Material chosen and why
Delrin® 100 was chosen for its unique balance of stiffness and strength
10
Strain (%)
The exceptional elongation coupled with stiffness makes
Delrin® suitable for snap fits
Description/Application
Clothes peg
PERFORMANCE
Creep
The fac rs
affecting creto
ep are:
Creep is defined as time dependent
strain, resulting from stress.
* Stress level
* Time
* Temperature
1h
10 h
20
h
100
0h
50
00
h
10
00
0h
Isochronous stress/strain
D e l r i n® 1 0 0 @ 2 3 ° C
Back to index
100
20
d)
te
jec
ro
(p
0
10
Stress (MPa)
00
0
h
15
Delrin® Acetal Resins
have extremely good
creep resistance for an
unreinforced polymer
10
5
0
0
0,5
1,0
1,5
2,0
2,5
Always try
to design parts
so that they are
not permanently
loaded
Total strain (%)
Material chosen and why
Delrin® 100 was chosen for its good spring characteristics and superior creep
compared with polyamide, polypropylene and acetal copolymer
Upon removal of a 14 MPa deforming stress,
Delrin® immediately recovers 40% of the imposed strain
21
Description/Application
Car window guides
PERFORMANCE
Stress relaxation
Stress relaxati
on
is particularly
important wh
en
considering
press-fit assem
bly
Stress relaxation is defined as
decrease of the stress required to
maintain constant strain.
22
Back to index
Te n s i l e s t r e s s r e l a x a t i o n o f
D e l r i n® 1 0 0 a n d 5 0 0 @ 2 3 ° C
100
% of initial stress
80
Stra
in 0
,3%
. 17
MPa
0,9%
. 34
MP
a
12
,5%
5%.
.Yi
6
6M
eld
Pa
po
int
str
ain
69
MP
a
40
20
10
0,01
0,1
1,0
10
100
1000
10000
Hours
Material chosen and why
Delrin® 100P was chosen for its good friction properties and a balance of
impact and creep resistance with high dimensional stability
Stress free mouldings may be obtained by annealing Delrin®
at 160°C for 45 mins
23
Description/Application
Tool changer carousel
PERFORMANCE
Fatigue
Back to index
24
Fatigue failure
stress of Delr ®
in
compared wit
h
other plastics
10 6 cycles, 23
°C
When materials are stressed
cyclically at high levels of stress
in relation to their tensile strength,
they tend to fail at levels of stress
below their ultimate tensile
strength.
Material
Polycarbonate
ABS
This phenomenon is termed
“fatigue failure.”
Polypropylene
Delrin® aceta
l
Stress (MPa)
50
Stress
(MPa)
10
11
15
32
40
30
20
10
Cycles to failure
0
10 3
Material chosen and why
Delrin® 100 was chosen for the best balance of stiffness and strength coupled
with flex fatigue resistance needed for the spring fingers of the tool gripper
10 4
10 5
10 6
Delrin® Acetal Resins have extremely high resistance
to fatigue failure from –40°C to +80°C
10 7
25
Description/Application
Rollerblade brake
PERFORMANCE
Impact Resistance
Impact resistance is defined
as the ability to withstand a
sudden blow rather than a
slowly applied load.
▲
See also
Effect of Radii in
‘Design Basics’
Back to index
20
60
15
50
10
Izod Impact v Temp
Delrin 100
40
R
5
0
-40
30
-20
0
20
40
60
Temperature, °C
20
10
500
500T
100
100T
100ST
Charpy Impact Strength (23°C)
Material chosen and why
Delrin® 100ST was chosen for the best combination of stiffness and
impact resistance at low temperature, combined with good mouldability
Delrin® acetal maintains its high toughness
down to very low temperatures
0
27
Impact strength, kJ/m2
Impact strength, kJ/m2
26
Description/Application
Moped brake lever
PERFORMANCE
UV Resistance
Back to index
28
Colours
500
1000
0,5
x27UV BK
x07
x0
BK
0B
K
Relative Gloss
1,0
0
2
Exposure, kJ/m
Material chosen and why
Delrin® 127UV was chosen for its excellent balance of mechanical
properties combined with good UV resistance
Relative Tensile Strength
Typical values for Delrin® grade 527UV compared with other grades.
1000
500
1,0
0,5
R
UV Stabilised
Sta
nda
rd
0
Accelarated Interior Weathering
according to SAE J-1885
Exposure, kJ/m2
The Delrin® UV family of resins are well suited for sporting goods and other
items which are used outdoors but stored indoors
29
▲
Acetal resins, like most
polymers, are affected by
light, particularly sunlight
which includes ultra-violet
radiation of wavelength
290-400 nm.
Colour
ed
offer so Delrin ® resin
s
m
protect e UV
io
of carb n. High levels
on blac
ka
an effec
tive UV ct as
for non
s
-critical creen
applicat
outdoo
r
ions
Description/Application
Bearing roll cages
PERFORMANCE
Temperature
Back to index
The highly crystalline
nature of Delrin® means it
is suitable for short-term
exposure to temperatures
close to the melting point
of 177°C.
Air Temperature (0C)
30
100
75
50
After 1 year
at 100°C
Delrin® retains
80% of its
tensile strength
1
2
5
10
Exposure time in years for
which tensile strength in
excess of 55 MPa is retained
Material chosen and why
Delrin® 100 was chosen for its good thermal stability combined
with a low coefficient of friction and superior impact resistance
Key The
Charac rmal
teristic
s
Proper
ty
°C
Melt te
mperat
u
r
e
Vicat So
177
ftening
10 N
50 N
174
Relative
160
Therma
l
Index (
w/o im
pact)
HDT (1
90
,8 MPa)
Ball Pre
115
ssure Te
st
165
Specific
Heat
Therma
0,35
l
Conduc
tivity
0,30
(W/m •
to
K)
0,37
If you need higher temperature resistance,
consider DuPont Zytel ® nylons , Crastin® and Rynite®
polyesters or Zenite™ LCPs.
The thermal stability of Delrin® means it finds use
in applications from –50°C to +90°C
31
Description/Application
Pool cleaner swivel bearing
PERFORMANCE
Chemical Resistance
ting
rs affec are:
o
t
c
a
f
The
sistance
e
r
l
a
c
i
chem
Back to index
32
tration
Concen
* ime
* T emperature
* T tress Level
S
*
14 Alkali
Do not use Delrin®
9
7 Neutral
in strong acids or
bases outside the
4
range of pH 4 to 9
0 Acid
Material chosen and why
Delrin® 500P was chosen for its excellent wear properties, chemical
resistance, snap-fit ability and dimensional stability
CHEMICAL
BEHAVIOUR
Acetic acid (5%)
Acetic acid (50%)
Acetone
Air (all pressures)
Alcohol (all types)
Ammonia (10%)
Aniline
Benzene
Bleaching fluid (10% chlorine)
Brake fluid
Butane
Calcium chloride (10%)
Carbon dioxide
Carbon monoxide
Chloracetic acid (10%)
Chlorine gas
Chlorinated water < 0,5 ppm
Chloroform
Chromic acid (10%)
Citric acid
Cyclohexane
Detergents
Diesel fuel
Ethanol
Ethyl acetate
resistant
unsatisfactory
resistant
resistant
resistant
unsatisfactory
limited resistance
resistant
unsatisfactory
resistant
resistant
resistant
resistant
resistant
unsatisfactory
unsatisfactory
resistant
limited resistance
unsatisfactory
resistant
resistant
resistant
resistant
resistant
resistant
Delrin® has excellent resistance to moisture, gasoline,
lubricants, solvents and many neutral chemicals
33
Description/Application
Fuel level device
PERFORMANCE
Chemical Resistance cont.
Back to index
34
Material chosen and why
Delrin® 500P was chosen for its good petrol resistance,
good mechanical properties and ease of moulding
CHEMICAL
BEHAVIOUR
CHEMICAL
BEHAVIOUR
Ethyl ether
resistant
Nitrous acid
unsatisfactory
Ethylene glycol
resistant
Nitrous oxide (dry)
unsatisfactory
Formaldehyde (37%)
resistant
Oils (food)
resistant
Formic acid
unsatisfactory
Oils (mineral)
resistant
Fuel oil
resistant
Oleic acid
resistant
Gasoline
resistant
Palmitic acid
resistant
Glucose (sat.sol.)
resistant
Paraffins
resistant
Heptane
resistant
Perchloric acid (10%)
unsatisfactory
Hexane
resistant
Phosphoric acid (30%)
unsatisfactory
Hydrochloric acid (10%)
unsatisfactory
Phthalic acid
resistant
Hydrofluoric acid
unsatisfactory
Potassium hydroxide (10%)
unsatisfactory
Hydrogen peroxide (1%)
resistant
Propane (liquified gas)
resistant
Hydrogen peroxide (30%)
unsatisfactory
Sodium chloride (10%)
resistant
Hydrogen sulphide
unsatisfactory
Sodium hydroxide (10%)
unsatisfactory
Insecticides
resistant
Sodium hypochlorite (5%)
unsatisfactory
Isoctane
resistant
Sulfur dioxide
unsatisfactory
Jet fuel / kerosene
resistant
Sulphuric acid (30%)
unsatisfactory
Lubricating oil
resistant
Tetrahydrofuran
resistant
Methyl chloride
limited resistance
Toluene
resistant
Methylene chloride
limited resistance
Trichloroacetic acid
unsatisfactory
Methyl ethyl ketone
limited resistance
Trichloroethane (1,1,1)
resistant
Mineral oil
resistant
Turpentine / white spirit
resistant
Motor oil
resistant
Urea (5%)
resistant
Nitric acid (10%)
unsatisfactory
Vinegar
resistant
35
T Y P I C A L A P P L I C AT I O N S
®
Do it in Delrin . . .
Ski Bindings
Back to index
Toughness @–40°C
UV performance
36
Clips
Elongation, fatigue
strength
. . . nothing does it better
Lighters
Zips
Low friction, bright
colours
Fasteners
Economical, toughness
Gears
Chemical resistance
Pressure vessel
Door Handles
Stiffness, low friction,
UV performance
Conveyors
Strength,stiffness, low
wear, low friction
Low wear, quiet
operation
37
Fuel Systems
Chemical resistance
Speaker Grilles
Easy flow, impact performance
The exceptional balance of properties has led to
a diverse use of Delrin® around the world
Description/Application
Spring clips
DESIGN BASICS
Radii
use of radii
has three ma
in
functions
see
also
Impact
Performace
▲
* Reduces notch effect
* Helps material flow
* Eases ejection from
Back to index
mould
Stress Factor
P = Applied Load
R = Fillet Radius
T = Thickness
38
P
39
R
3,0
2,0
T
2,0
Usual
1,5
1,0
0
0,2
0,4
0,6
0,8
1,0
1,2
1,4
Always use radii
at rib junctions
and stressed areas
but also consider
thread terminations,
knurled inserts and
surface textures
R/T
Material chosen/Design comment
Delrin® 111P was chosen for this application. Radii lowers stress
concentration when parts are put under load
Delrin® like many plastics, is notch-sensitive but unlike other resins
it has high impact strength at low temperatures
Description/Application
Ratchet mechanism
DESIGN BASICS
Uniform Wall Thicknesses
Back to index
ess
ll thickn
a
w
n
e
v
E
gives:
kage
en shrin rtion
v
E
* less disto
–
set-up
* Eveqnuickest moulding
–
cycle
rial
ss mate
e
L
* low cost
–
40
Material chosen/Design comment
Delrin® 500P. Low distortion and cost efective part ensured
by use of even wall thickness
Choosing the correct wall
thickness for a moulded part
is a function of end use
constraints (what does the
part have to do?), moulding
factors, (what is the thinnest
section that can be moulded?)
and overall cost.
The exact thickness may be
estimated by the use of Finite
Element Analysis (FEA) used
in both part design and flow
analysis, but where possible
should be relatively constant
throughout.
Even wall section will greatly benefit highly crystalline
polymers such as Delrin®
41
Description/Application
Cross beam
DESIGN BASICS
Ribs
Proper use
of ribs will:
Back to index
way
effective of
n
a
e
r
a
Ribs
igidity
ve the r
o
r
p
m
i
to
parts.
moulded ,® ribs should be
rin
For Del e general wall
th
2
1 2 to / 3
1 ° to
/
s, with / 4 side.
s
e
n
k
c
i
th
er
t angle p
1 2°draf
/
42
* Save material and weight
* Shorten moulding cycle
voids in thick
* Eliminate
sections
Sink marks caused by
ribs may be hidden
by use of textured surface or
suitable interruption in the
area of the sink.
Material chosen/Design comment
Delrin® 100P enables increased stiffness to be achieved by
use of ribs without compromising surface finish
If ribbing is unacceptable, Delrin® 510GR and 525GR
offer significant increase in stiffness
43
Description/Application
Fuel flange
DESIGN BASICS
Bosses
Back to index
Bosses are used for
for
mounting purposes or les.
ho
nd
ou
reinforcement ar
As a rule the outside
ould be
diameter of a boss sh
le
2 to 3 times the ho
diameter.
Heavy sections may be
e boss
avoided by stepping th
off the adjoining wall.
ns.
Use radii at all junctio
44
Material chosen/Design comment
Delrin® 511P. Boss and linking rib design
provides accurate hole centres
*
*
*
Boss Design
Hole dia = 0,75 x nominal
dia of screw
Boss dia: 2 to 3 times
hole dia
Hole depth 2 x nominal
screw dia minimum
Always use screws designed for
plastics when considering
assembly. These may be single
or twin-start threaded or
trilobular screws. Repeated
assembly and disassembly is
possible with Delrin.®
Weld lines should be avoided in bosses. Delrin® being generally
unreinforced, has excellent weld line strength
45
Description/Application
Industrial valve
DESIGN BASICS
Threads
Back to index
Round threads
Correct termination of threads
1mm
When required, threads may
be automatically moulded
into the part, eliminating the
need for mechanical threadforming operations.
For external threads, it may
be possible to locate the
parting line on the centre of
the thread.
For internal threads, an
automatic unscrewing device
is used in the tool.
46
47
▲
To avoid ‘squeak’ on heavily
loaded threads, consider the
Low Wear, Low Friction grades
of Delrin®
Material chosen/Design comment
Delrin® 500P. Moulded thread form avoids machining
ttress
Use of a bu ill
w
type thread ssary
e
c
e
n
n
avoid u
on
s
e
radial forc rt
a
p
the mating
The dimensional stability of Delrin® makes it very suitable
for the moulding of accurate thread forms
Description/Application
Cable guide
DESIGN BASICS
L
Snap Fits are a cost effective
way of assembling parts
together without the use of
special tools.
R
s
r Snap Fit
Cantileve
s long
Make ‘L’ a
as possible
p fit lug
Taper sna
at root
Use radii
*
*
*
Delrin® is also excellent for
circular and spherical snap
fit designs
Material chosen/Design comment
Snap fit in Delrin® 500 gives strong, rattle-free connection
Usually the parts are at rest
before and after assembly
and pass through a stressed
condition as the snap fit is
made to work.
With Delrin®, a single use snap
fit may be stressed up to 8%
strain (Delrin® 100). For a
frequently used one refer to
the fatigue stress graph
The combination of stiffness and elongation makes
Delrin® very suitable for snap fits
▲
Back to index
48
Snap Fits
49
Shoehorn prototype
RAPID PROTOTYPING
Back to index
In order to test parts in the actual
material it is normally necessary
to mould them. Due to the ease
of machining of Delrin®, it may
be possible to prototype parts
by NC machining, utilising the
CAD data which describes
the part geometry.
* dKuerep heat generat
ed
ing m
minimu achining to a
m
Suppor
t
and lon thin walls
g parts
Be awa
r
effect o e of the notch
f machin
parts
ing
*
*
Create
Tool
Paths
CAD Data
3
2
1
Machine
Stock Shapes
(Block, Rod)
4
5
5a
Modify
Geometry
Prototy
ping tip
s
Test Parts
Hand Finish
50
51
6
7
Mould Parts
Delrin® has excellent machining characteristics
using conventional tools
CNC machining of simple shapes possible in Delrin®
Delrin®
stockists/
machinists
▲
NC Machine
Mould Tool
Rod stock, slab
STOCKISTS/MACHINISTS
Back to index
Contact your DuPont representative for detailed
information on your local Delrin® stockist
52
53
Details of companies experienced in machining Delrin® acetal resins
are also available from your DuPont representative
Always ask for Delrin® by name
Delrin® The heart of a good product
COLOURS
Custom colo
urs are
available as fu
lly
compounded
product
from DuPont
or by
masterbatch
from
pigment supp
liers
Typical reference
codes for
Delrin® colours
NC = Natural
Back to index
BK = Black
WT = White
GY = Grey
Ideally any masterbatch
should be acetal based
GN = Green
BL = Blue
YL = Yellow
RD = Red
SHRINKAGE
(%)
g e v. C o
lour
2,0
1,9
1,8
No heavy metals are used in Delrin® Colours
GN
55
RD
COLOUR
GY
BL
BK
YL
WT
1,7
NC
54
Pigments
may affect
shrinkage –
test first!
Shrinka
2,1
Description/Application
Venting system grille
PROCESSING
The most important variables
in producing good parts by
injection moulding are:
Back to index
* Melt temperature
* Injection speed
* Hold pressure
* Screw forward time
* Mould temperature
Above all, a good quality
homogeneous melt is required.
Typical set-up conditions for
Delrin® 100 are shown below.
56
Material chosen and why
Delrin® 927UV was chosen for its excellent mouldability and impact resistance.
Its resistance to UV and easy colourability are additional assets
Grades based on
the ‘P’
stabilisation syst
em are suitable
for hot runner to
ols,
these include
100P, 500P, 900P,
1700P
127UV, 527UV, 92
7UV, 1727UV,
111P, 511P, 911P.
Always dry toughened grades
for 4 hours at 80°C
Melt
Temp
(°C)
Mould
Temp
(°C)
Hold
Pressure
(MPa)
Hold Pressure
Time (s/mm)
Max Hold
Up Time
(min)
Shrinkage
(%)
215
90
100
8
30
1,9 - 2,2
For specific processing information ask for the free booklet
‘Delrin® Moulding Manual’
57
Description/Application
Golf tee
REGRIND & RECYCLING
Back to index
G
REGRIND
RECYCLIN
>
POM<
f
o
bination
Up to 25%
The com d elongation
o
n
a
ground sp f properly
s
®
stiffnes es Delrin so
runners m rues and
k
that ma snap fits also
a
in
with virgin y be mixed
e
effective at parts may b
little or n resin with
h
t
s
r
n
io
a
r
e
p
o
m
bled
mechanica effect on
disassemcycling.
l propertie
s.
to re
y
T
it
o
il
u
g
b
h
a
e
t
n
s
ed
g term
need to b grades will
The lon ® means that
e dried
to mouldin prior
of Delrin be reground
g.
ay
parts m oulded with
F
o
r glass
and rem ffect on
grades, us reinforced
little e ties.
ea
on the gr slow speed
proper
y
inder roto
g
r
r.
an ene
is
n
io
t
a
Inciner nt alternative
efficie
58
59
Material chosen and why
Delrin®100 regrind was chosen for the shank. Capable of
withstanding high impact, it provides the correct rigidity
It is important to use analytical techniques in part design
to reduce the impact of recyclate on the environment
Description/Application
Ski adjuster
LASER MARKING
Back to index
Laser marking is
particularly suitable when
the batch sizes are small and
marking variability is required
(e.g. serial numbers or
different languages).
A range of colours
specially optimised
for laser marking is
available in Delrin®.
Tested with several
Nd:YAG laser
systems, these
colours provide high
contrast markings
with almost no
engraving
Advantage
s
* pHroigcherate contactless
ss
F
le
x
ib
il
* of layo ity, easy change
ut and cha
racter
type
No surfac
e
no solvent, pre-treatment,
no ink
High durab
ility of the
marking
*
*
Colours for laser marking 500LM ...
. . . BK-L01 Black
. . . BL-L01 Blue
. . . BN-L01 Brown
. . . GN-L01 Green
60
Material chosen and why
Delrin® 500LM BK-L01 was chosen for its clarity of laser marking
plus its mechanical properties
▲
ication by
ight Amplif
L ASER = L
Radiation
f
o
Emission
d
te
la
u
im
St
. . . GY-L01 Grey
. . . RD-L01 Red
. . .WT-L01 White
See also Delrin® colours
61
Description/Application
Medical tube clip
M E D I C A L A P P L I C AT I O N S
✠
CAUTION
Back to index
Do not use DuPont
materials in medical
applications involving
permanent implantation in the
human body or permanent
contact with internal body
fluids or tissue.
Do not use DuPont
materials in medical
applications involving brief or
temporary implantation in the
human body or contact with
body fluids or tissues unless
the material has been provided
directly from DuPont under a
contract which expressly
acknowledges the
contemplated uses.
62
✚
DuPont makes no
representation, promise,
express warranty or implied
warranty concerning the
suitability of these materials
for implantation in the human
body or in contact with
internal body fluids or tissues.
For food contact
or pharmaceutical
applications, regulatory
compliance statements are
available, please
contact your local DuPont
representative for
details.
Delrin® acetal resin is not certified for implants
Material chosen and why
Delrin® 500P was chosen for its chemical resistance and springiness
63
Technical Information
F U RT H E R R E A D I N G
▲
Delrin® Product guide
and properties
Design
Information
▲
Moulding
Manual
▲
wide
DuPont has a
terature
selection of li
ific
covering spec
s
ea
application ar
ances,
such as Appli
Electrical,
Automotive,
,
Furniture etc.
a
h
together wit
n Principles
General Desig
ich covers all
handbook wh
eering resins
DuPont engin
Main Literature for Delrin®
▲
Back to index
To access further
information concerning
any topic covered in this
binder, please contact
your local DuPont office
Access information on
Delrin® at our internet
address:
http://www.dupont.com/
enggpolymers/europe
The general brochure covering all DuPont engineering polymers
is called ‘From concept to commercialisation’
64
A wealth of experience available in various formats
65
Delrin® Makes the Difference
F U R T H E R I N F O R M AT I O N
Belgique/
België
España
Norge
Suomi/
Finland
Tel (15) 44 14 11
Fax(15) 44 14 09
Tel (3) 227 60 00
Fax(3) 227 62 00
Tel 67 14 10 00
Fax67 14 02 20
Tel 09-725 66 100
Fax09-725 66 166
Bulgaria
France
Österreich
Sverige
Tel (2) 66 59 13/66 57 36
Fax(2) 65 63 29/66 56 11
Tel 01 45 50 65 50
Fax01 47 53 09 67
Tel (01) 512 35 71
Fax(01) 512 35 71 12/
512 35 71 31
Tel +46 8-750 40 20
Fax+46 8-750 97 97
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Slovenská Rep.
Hellas
Polska
Türkiye
Tel (02) 574 14 111
Fax(02) 574 14 150
Tel (01) 680 16 14
Fax(01) 680 16 11
Tel (22) 635 04 01
Fax(22) 691 09 00
Tel (212) 275 33 83
Fax(212) 211 66 38
Danmark
Israël
Portugal
Ukraine
Tel +45 43 62 36 00
Fax+45 43 62 36 17
Tel (3) 528 62 62
Fax(3) 282 717
Tel (2) 69 24 25/69 26 64
Fax(2) 600 02 07
Tel (044) 2949633/269 1302
Fax(044) 269 1181
Deutschland
Italia
Russia
United
Kingdom
Tel (06172) 87 0
Fax(06172) 87 27 01
Tel (02) 25 302.1
Fax(02) 92 107 845
Tel (095) 797 22 00
Fax(095) 797 22 01
Tel (01442) 34 65 00
Fax(01442) 24 94 63
Egypt
Maroc
Schweiz/
Suisse/Svizzera
Tel (02) 392 78 66
Fax(02) 392 84 87
Tel (2) 27 48 75
Fax(2) 26 54 34
Tel (061) 326 66 00
Fax(061) 326 62 04
Romania
Slovenija
Magyarország
Back to index
Start with DuPont engineering polymers
66
Delrin®. Chosen for reliability of performance in many
thousands of engineering components all over the world
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