Title: THERMOFORMING High Density Polyethylene sheet using Temperature-CONTROLLED ALUMINUM TOOLING
1THERMOFORMING High Density Polyethylene sheet
using Temperature-CONTROLLED ALUMINUM TOOLING
- Brett Braker
- MET496
- April 28th, 2011
2Individual Performance Objectives
- Show the importance of temperature-controlled
molding in thermoforming. - Prove that HDPE can be a relevant material to use
in thermoforming, instead of just amorphous
materials. - Get project results by spring break, one week
- Create a lab for future curriculum
3Purpose
- Almost all of thermoforming industry uses
amorphous materials - Use molds that are not temperature-controlled
- Material options Better quality parts
4Material
- 50 High Density Polyethylene sheets
- 22.5 (MD) x 40 (TD) x 0.125
- Levant finish on top, smooth bottom
- 285-385F forming temp, 330F optimum
- 170F ejection
- Density 0.0345 lb/in3 (0.955 g/cc)
- 66.3 Shore D hardness
- Ultimate Tensile Strength 3,800 psi
- Tensile Yield Stress 3,829 psi
- Deflection temp with 66 psi 166.5F
5Grid Layout
- Original Idea
- Penn College Printing Department
- Pat Bundra
- Screen Printing
6Non Temperature-Controlled Mold
- Renshape 472 Medium Density Polyurethane Board
(REN) - Wooden base, machined Polyurethane core
- Exact same dimensions as aluminum mold
- 15.25 x 33.125 x 4.2
7Renshape Cycle
- Bottom platen
- Material Build-up
- Stretching
- Material Properties
8Renshape Cycle
9Renshape Cycle
- Top platen
- Machine settings
10Renshape Cycle
- Perfect cycle
- Rails too close
- Mold too deep
- Ovens too hot
11Production-Style Run
- 10 parts
- Continuous cycle
- Measurements
- Temperatures
- Aluminum Jig
- Thicknesses
- 2 minutes after forming
- 24 hours after forming
12Temperature Measurements
- Mold
- Front
- Top
- Back
- Sheet temp before and after forming
- Room temperature
- Humidity
- All taken with infrared gun
13Aluminum Jig Measurements
- 15.875 x 33.500
- Corner 3-4
- Height
- 5.562
- 5.562 x h
- Jig thickness
- Aluminum blocks
- Meter stick height
- Dial calipers
14Thickness Measurements
- Drill with hole saw attachment
- 1-inch holes
- Left, Right, Front, Back, and Top of part
- 2 minutes Left side
- 24 hours Right side
- Discs
- Dial calipers
15Measurement Formulas
- After jig measurements
- Match corresponding points (1-8, 6-3, 5-9, etc.)
- Take combination of both and subtract from jig
dimension - Y1 15.875 (0.1025 0.4865)
- Y1 15.2860
- Points show warpage
- Y1 shows shrinkage
16Renshape Mold Production
- I.R. eye 370F
- Heating 120 seconds
- Cooling 180 seconds
17Renshape Production Results
18Renshape Production Results
19Renshape Production Results
20Renshape Production Results
21Aluminum Mold Production
- I.R. eye 370F
- Changed to 360F before Sheet 5
- Cooling time 100 seconds
- Changed to 120 seconds before Sheet 4
- Changed to 150 seconds before Sheet 5
- Changed to 130 seconds before Sheet 7
- Changed to 120 seconds before Sheet 8
- Changed to 110 seconds before Sheet 9
- Circulator temp 200F
22Aluminum Mold Production Results
23Aluminum Mold Production Results
24Aluminum Mold Production Results
25Aluminum Mold Production Results
26Renshape vs. Aluminum
27Renshape vs. Aluminum
28Renshape vs. Aluminum
29Renshape vs. Aluminum
30Renshape vs. Aluminum
31Renshape vs. Aluminum
32Design Of Experiment
33Design Of Experiment
34Renshape Tensile Testing
35Aluminum Tensile Testing
36Renshape vs. Aluminum
37Conclusion
- Temperature-controlled aluminum tooling shows
much more consistency with HDPE than Renshape
does. - Much less warpage, shrinkage, and higher
dimensional stability as a result - HDPE needs a temperature-controlled mold to be
deemed relevant in the thermoforming industry.
38Individual Performance Objectives
- Show the importance of temperature-controlled
molding in thermoforming. - Prove that HDPE can be a relevant material to use
in thermoforming, instead of just amorphous
materials. - Get project results by spring break, one week
- Create a lab for future curriculum
39References
- Defosse, Matthew. "Thermoforming." Modern
Plastics Worldwide World Encyclopedia 2006. Los
Angeles, CA Canon Communications, 2006. 106.
Print. - Harper, Charles A. Handbook of Plastic Processes.
Hoboken, NJ Wiley-Interscience, 2006. Print. - Illig, Adolf, and Peter Schwarzmann. Thermoforming
A Practical Guide. Munich Hanser, 2001. Print. - Peacock, Andrew J. Handbook of Polyethylene
Structures, Properties, and Applications. New
York Marcel Dekker, 2000. Print. - "Sheet/Thermoforming Grade HDPE." www.matweb.com.
Material Property Data. Web. lthttp//www.matweb.co
m/search/DataSheet.aspx?MatGUIDc35a0a3e740e424fad
260a5da2c2b50ackck1gt.
40Acknowledgements
- John Bartolomucci, Pennsylvania College of
Technology - Patrick Bundra, Pennsylvania College of
Technology -
- Todd Chrismer, McClarin Plastics
-
- Todd Kennedy, McClarin Plastics
-
- Roger Kipp, McClarin Plastics
-
- Aaron Lapinski, Pennsylvania College of
Technology -
- Gary McQuay, Plastics Manufacturing Center
41Questions?