The document describes a new thermoformability testing device called Technoform. It aims to address limitations of current testing methods by evaluating materials under conditions that closely mimic the full thermoforming process. Technoform tests specimens through heating, 3D stretching, forming, and cooling. It provides quantitative data on various metrics like sag distance, forming force, and shrinkage. The document outlines Technoform's design and capabilities, and provides several examples showing how it can evaluate the effects of various material and process parameters on thermoformability.

1. Technoform – For Rapid, Repeatable
Thermoformability Analyses
Dr. Amit Dharia
Transmit Technology Group, LLC, TX
www.transmit-technology.com

2. Outline
® Properties –Thermoforming Process
relationship
® Current test methods
® Description of Technoform
® Application and data interpretation
® Products – Basic, Standard, Advanced
® Conclusion

3. Thermoforming Process
® Extruding sheet stock
® Heating sheet above Tg
® Stretching heated sheet in rubbery state
® Cooling
® Trimming
® Finishing

4. Structure - Properties -
Thermoformability
® Rate of change of strength with the
change in strain rate at forming
temperature
® % Crystallinity – Breadth of rubbery
Plateau
® Molecular weight, Molecular weight
distribution, molecular architecture
(branching, crosslinking) – MFR, Melt
Elasticity

5. Other parameters
® Density - % filler, type of fillers, degassing
® Geometry – Thickness, area, multi-layered
structures, adhesion between layers
® Residual stresses between and within in
extruded layer sheet stock
® Thermal diffusivity (Cp, K. Rho)
® Extrusion quality ( gels, unmelts,
thickness variation, grain patterns)
® Color (IR absorption)

6. Current tests
® Low shear melt viscosity (MFR, RMS)
® Melt Tension (Draw Force –Melt
tension, Break Velocity -extension)
® Sag Test (sag distance, sag time)
® Hot Creep Test
® DMA (Relaxation time)

7. Major disadvantages of current
methods
® Most tests are conducted in melt or near melt
phase
® Test Specimens does not reflect actual test
geometry (shape, size, clamping mode)
® Tests does not account for orientation, thermal
stresses, thickness variations
® Isothermal environment, does not account for
transient nature of heating/ cooling
® Effects of secondary process parameters can not
be evaluated
® Results cannot be directly used.

8. What processors want to know?
® Will this material thermoform?
® Will this new material process the same?
® Will this lot process the same as the last one?
® Why this lot does not process the same?
® How much time is needed to heat the sheet?
® How fast material will heat?
® What is the right forming temperature range?
® Will melt adhesion between layers survive
heating and stretching step?
® Will material discolor, fed or degrade during
heating?

9. What processors want to
know? -II
® What is the maximum draw down?
® How fast part can be made?
® What is the MD and TD shrinkage?
® Will material tear at the corners and ribs?
® How much regrind can I use?
® Will grains retain shape and depth?
® Does extruded sheet have gels or
unmelts?

10. What Industry Needs?
® A standard test method which reflects all unit
steps – heating, 3D stretching, forming, and
cooling
® A test equipment which can be precisely
controlled, is rapid, easy to use, provides
repeatable and quantitative information, using the
lease amount of material.
® Easy to use “Thermoformability Index” standard
for comparing, contrasting effects of selected
process/ material variables

11. TECHNOFORM TM
Patent PendingTTG
TECHNOFORM

12. Schematics of Technoform
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13. Typical Data input
® Mode of operation – Plug Assisted, Vacuum
® The heating element distance from the sheet
surface
® The heating element temperature
® The sheet temperature
® Heat Soak time at given temperature
® Plug velocity (2 to 200 mm/second)
® Plug Delay Time
® Plug Temperature
® Part Cooling time

14. Typical user Input Screen
Sag Distance
Thinning
Strain
hardening
Forming Depth mm
Thermoformability Index=
slope

15. Typical Data Output
® Heating rate (Delta C/ time) = f (thickness)
® Sag distance
® Forming force (Stress) vs. forming
distance (strain)
® Forming Force vs. time
® Yield force
® Forming force vs. actual temperature
® Shrinkage (manual measurements)

16. Effect of Heating time
Force vs. Depth (180 C, Isothermal)
4" dia hemi-spherical plug, 20 ipm
(effect of pre-heat time)
0
10
20
30
40
50
0 20 40 60
Depth, mm
Force,lbs
10 min
15 min

17. Plug Material and Shapes
® Truncated cone with flat end (2.5” Top
D, 0.75 “ Bottom D, 4” Height)
® Truncated cone with Rounded End (2.5”
Top D, 1” D bottom, 4” Height)
® Hemisphere of 3.5” Diameter
® All tools made of Foam Epoxy

18. Effect of Plug Temperature
35 Mil Black HIPS, 130 C,40 mm/s
- No control -
0
2
4
6
8
10
12
0 50 100 150
Draw Depth, mm
Force,Lbf
Series1
Series2
Series3

19. Effect of controlling Plug Temperature
HIPS, 40 mm/second with T control
HIPS @130 C, 40 mm/second
Plug cooled for five minutes
0
2
4
6
8
10
12
0 20 40 60 80 100 120
Depth, mm
Force,Lbf
#1
#2
#3
#4

20. Effect of Plug Geometry
Force vs. Depth 180 C, 40 mm/s
Hemi-Spherical Plug with 4 " Diameter
0
5
10
15
20
25
30
35
0 10 20 30 40 50
Depth mm
Force,lbsf
1
2

21. Effect of plug material
HIPS, 170 C, 40 mm/second, 35 mil
0
1
2
3
4
5
6
0 20 40 60 80 100 120
Depth (mm)
Force(lb)
WF WFT Bix

22. Effect of forming Speed on HDPE @ 150 C
Effect of Forming Speed on HDPE
0
2
4
6
8
10
0 50 100 150
Distance (mm)
Fromingforce(N)
20 mm/sec
30 mm.sec
50 mm/sec

23. Heating rates for various plastic materials
(Heater at 600 C, 3” from upper, 2” from lower)
30
80
130
180
230
0 20 40 60 80
t (seconds)
T(c)
PP
HDPE
HIPS
PVC
ABS
Acetal
PMMA
Nylon

24. Effect of Crystallinity
0
5
10
15
20
25
30
50 70 90 110 130
Forming distance, mm
Force(N)HDPE PP HIPS PETG ABS PMMA PVC

25. Comparison of various PE
LDPE, LLDPE, MDPE @ 60 mm/s
0
5
10
15
20
25
30
35
0 20 40 60 80
Depth, mm
Force,lbf
LDPE120
LLDPE120
MDPE120

26. Effect of Forming Temperature
0
2
4
6
8
10
12
14
125 145 165 185
Temperature (C)
Force(N)
ABS
PP
HDPE
HIPS
PETG
PMMA
ACETAL

27. Force100 = f (T, V, material)
® F(ABS) =9.2348 -0.0547 T (R2 =99%)
® F(PMMA)=7.1587 -0.0341 T(R2=98%)
® F(PETG)=10.096 -0.0601 T (R2=92%)
® F(HIPS)=9.6782 - 0.0503T(R2=93%)
® F(HDPE)=5.2771 -0.0266 T (R2=86%)

28. Effect of Thickness
PC/ABS, 40 mm/sec, 200 C
0
1
2
3
4
5
6
7
8
9
0 20 40 60 80 100
Depth (mm)
Froce(lbf)
95 150 250

29. Lot to lot variation in TPO
170 C, 40 mm/second, 190 mil
0
1
2
3
4
5
6
7
8
9
10
0 10 20 30 40 50 60 70
Depth (mm)
Froce(lbf)
1-1 1-2 1-3

30. Effect of Color
Co PP, 160 C, 40 mm/second, 35 mil
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0 20 40 60 80 100 120
Depth (mm)
Force(lb)
0
2
4
6
8
10
12
blue red Metallic

31. Effect of thickness on the Heating Rate
0
50
100
150
200
250
0 500 1000
time (sec)
Surface
Temperature(C)
100 mil 150 mil 250 mil

32. Effect of % Regrind on formability TPO
20% regrind / Five Successive Extrusions
0
1
2
3
4
5
6
40 60 80 100 120
Forming Distance, mm
FormingForce,Lbf
1st
2nd
3rd
4th
5th

33. Effect of % Regrind in FR-ABS
0
2
4
6
8
10
12
14
0 20 40 60 80 100
Depth (mm)
Froce(lbf)
50% RG 100% RG

34. Comparison of filled vs. HMS-TPO
0
10
20
30
40
50
0 20 40 60 80 100
Distance (mm)
Force(N)
40HMSTPO 20HMSTPO
40 FTPO 20FTPO

35. Effect of adding HMSPP in PP
0
1
2
3
4
5
6
7
40 60 80 100 120 140
Form ing Dist ance, mm
FormingForce,Lbf
10%H MSPP 20%HMS PP 30% HMSPP
0
1
2
3
4
5
6
7
40 60 80 100 120 140
Form ing Dist ance, mm
FormingForce,Lbf
10%H MSPP 20%HMS PP 30% HMSPP
0
1
2
3
4
5
6
7
40 60 80 100 120 140
Forming Distance, mm
FormingForce,Lbf 10%HMSPP 20%HMSPP 30%HMSPP

36. Formability of HMSPP/PP Blends
0
2
4
6
8
10
12
10 20 30
%HMSPP
thickness(High/Low)

37. Comparison of Test Methods
Relaxation Time (s) Vs. Force @ 75 mm depth
R2
= 0.9968
0
2
4
6
8
10
12
0 2 4 6 8
Relaxation Time (sec)
FormignFroce(75mm)
PP, 165 C
HDPE,140C
HIPS,160 C

38. Processing window for E-3500
170 C, 40 mm/s, 190 mil
0
10
20
30
0 20 40 60 80 100
Depth (mm)
Force(lbf)
170 180 190 170TPO

39. Technoform Features
Basic Standard Advanced
Fixed heaters, 120 V Manual Adjustment Automated
Adjustment = F
(thickness, material)
Fixed Watt Fixed Watts Close loop
Chamber at Ambient Chamber T control Chamber T control
Speeds 0-120 mm/s 0-200 mm/second 0-200 mm/second
Plug T @ ambient Plug T @ ambient Plug T Controlled
Plug mode only Plug and Vacuum Plug and Vacuum
No Vacuum mode No Vacuum vs. depth Vacuum vs. Depth
record
Basic software Basic Software Advanced features

40. Conclusions
® Technoform is a simple to operate test
equipment is which closely reflects all unit
steps of the typical thermoforming
process and generates quantitative and
repeatable information in short time.
® The test data can be used in raw form to
compare or contrast various materials,
process parameters or can be further
modeled as a design or predictive tool.