brett braker met496 april 28 th, 2011. individual performance objectives show the importance of...
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Brett Braker
MET496
April 28th, 2011
Individual 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
Purpose
Almost all of thermoforming industry uses amorphous materials
Use molds that are not temperature-controlled
Material options = Better quality parts
Material 50 High Density Polyethylene sheets 22.5” (MD) x 40” (TD) x 0.125” Levant finish on top, smooth bottom 285-385°F forming temp, 330°F optimum 170°F 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: 166.5°F
Grid Layout
Original Idea Penn College Printing Department Pat Bundra Screen Printing
Non 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”
Renshape Cycle
Bottom platen
Material Build-up
Stretching
Material Properties
Renshape Cycle
Renshape Cycle
Top platen Machine settings
Renshape Cycle
“Perfect” cycle Rails too close Mold too deep Ovens too hot
Production-Style Run
10 parts Continuous cycle Measurements
TemperaturesAluminum JigThicknesses2 minutes after forming 24+ hours after forming
Temperature Measurements
MoldFrontTopBack
Sheet temp before and after forming Room temperature Humidity All taken with infrared gun
Aluminum Jig Measurements
15.875” x 33.500” Corner 3-4 Height
5.562”5.562 – x = hJig thicknessAluminum blocksMeter stick height
Dial calipers
BL 8 7 6
9 5
10 4
FL 1 2 3
Thickness Measurements
Drill with hole saw attachment1-inch holes
Left, Right, Front, Back, and Top of part 2 minutes – Left side 24+ hours – Right side Discs Dial calipers
Measurement Formulas
After jig measurements Match corresponding points (1-8, 6-3, 5-9, etc.) Take combination of both and subtract from jig
dimensionY1 = 15.875 – (0.1025 + 0.4865)Y1 = 15.2860”
Points show warpage Y1 shows shrinkage
Renshape Mold Production
I.R. eye – 370°FHeating – 120 seconds
Cooling – 180 seconds
Renshape Production Results
Renshape Production Results
Renshape Production Results
Renshape Production Results
Aluminum Mold Production
I.R. eye – 370°FChanged to 360°F before Sheet 5
Cooling time – 100 secondsChanged to 120 seconds before Sheet 4Changed to 150 seconds before Sheet 5Changed to 130 seconds before Sheet 7Changed to 120 seconds before Sheet 8Changed to 110 seconds before Sheet 9
Circulator temp – 200°F
Aluminum Mold Production Results
Aluminum Mold Production Results
Aluminum Mold Production Results
Aluminum Mold Production Results
Renshape vs. Aluminum
Aluminum Al 2 mins Al 72 hrs Al 2 mins Al 72 hrs
Dimensions Average Average St. Dev. St. Dev.
Y1 15.1864 15.0772 0.0532 0.0629Y2 15.3429 15.2224 0.0556 0.0498Y3 15.2405 15.1412 0.0387 0.0494X1 32.7307 32.4864 0.0815 0.0799X2 32.6969 32.5176 0.0234 0.0627Z 3.5513 3.5266 0.0566 0.0451
Thickness Average Average St. Dev. St. Dev.
Front 0.0939 0.0903 0.0021 0.0047Right 0.0838 0.0807 0.0064 0.0054Back 0.0846 0.0918 0.0028 0.0055Left 0.0810 0.0835 0.0021 0.0044Top 0.1029 0.1083 0.0017 0.0055
REN 2 mins 72 hrs 2 mins 72 hrs
Dimensions Average Average St. Dev. St. Dev.
Y1 15.2772 14.7679 0.0737 0.0817Y2 15.2703 14.6292 0.0916 0.1319Y3 15.2146 14.6189 0.1027 0.1786X1 32.8077 32.5823 0.0680 0.0540X2 32.7825 32.5545 0.0604 0.0547Z 3.6531 3.5861 0.1874 0.0854
Thickness Average Average St. Dev. St. Dev.
Front 0.0728 0.0640 0.0066 0.0063Right 0.0699 0.0541 0.0072 0.0036Back 0.0693 0.0590 0.0086 0.0056Left 0.0733 0.0536 0.0105 0.0034Top 0.1280 0.1207 0.0068 0.0037
Renshape vs. Aluminum
Renshape vs. Aluminum
Renshape vs. Aluminum
REN 72 hrs Aluminum 72 hrsWidth 3.816% Width 0.719%Length 0.691% Length 0.647%Height 1.836% Height 0.696%
OVERALL SHRINKAGE
Renshape vs. Aluminum
Renshape vs. Aluminum
Grid Shrinkage REN Aluminum
Top MD + 0.011" + 0.103"Top TD - 0.019" + 0.122"
Drawn MD + 1.508" + 1.005"Drawn TD - 0.025" - 0.021"
Design Of Experiment
High LowCooling Time 150 90
Circulator Temp 205 170I.R. Eye Temp 400 330
Run Cooling TimeCirculator
TempI.R. Eye
TempA*M A*O M*O A*M*O
1 - - - + + + -2 - - + + - - +3 - + - - + - +4 - + + - - + -5 + - - - - + +6 + + - + - - -7 + - + - + - -8 + + + + + + +
Design Of Experiment
Renshape Tensile Testing
Sample ID Yield Stress (psi) Max Stress (psi) Yield Elongation (%) Break Stress (psi) Modulus (psi) Max Energy (in*lb/in3) Max Elongation (%) TE Auto (%)
R4F 3100 3100 13.45 1949 39600 243 12.47 984R7F 2670 2670 13.62 109.7 82500 278 13.27 160R10F 2720 2720 15.62 1413 37300 305 15.62 848R1B 2920 2920 12.73 1962 52300 272 12.73 687R4B 3460 3460 14.09 1726 87600 331 12.46 409R7B 2540 2540 14.11 582 69500 268 13.5 299R10B 2520 2520 13.96 300 51600 244 12.84 550R1L 3270 3270 16.79 2420 36700 372 16.79 1039R4L 3150 3150 15.79 2190 35400 328 15.79 1039R7L 2340 2340 0 N/A 67100 250 13.59 295
R10L 2580 2580 18.71 1899 29300 291 16.58 1039R1R 2980 2980 16.61 2200 34000 307 15.57 1039R4R 3180 3180 14.16 2520 38200 290 14.16 1013R7R 2580 2580 17.9 1986 29000 296 16.85 1039R10R 2320 2320 15.55 1731 26600 239 15.55 1039
St. Dev. 354.667 354.667 1.786 770.055 19907.615 37.599 1.645 332.731
Renshape Mold Tensile Testing
Aluminum Tensile Testing
Sample ID Yield Stress (psi) Max Stress (psi) Yield Elongation (%) Break Stress (psi) Modulus (psi) Max Energy (in*lb/in3) Max Elongation (%) TE Auto (%)
A7F 2750 2750 13.92 818 970000 302 13.81 101.2A10F 2470 2470 13.566 703 59200 251 13.12 440A4B 3220 3220 14.71 1335 89600 356 13.97 248A7B 3510 3510 14.93 1046 1200000 403 14.44 435
A10B 2530 2530 14.7 37.6 81100 296 14.78 65A4L 2870 2880 18.23 861 29600 322 17.12 1044A10L 2260 2260 16.788 1606 25700 235 15.72 1039A4R 2970 2980 18.63 2240 33400 332 16.53 1039A7R 3040 3050 17.87 2170 334000 344 16.82 1039
A10R 2320 2320 15.799 1687 25900 265 16.84 1039
St. Dev. 405.221 406.613 1.848 691.224 434932.154 51.571 1.469 428.932
Temperature-Controlled Aluminum Mold Tensile Tests
Renshape vs. Aluminum
Tensile Results REN Aluminum
Yield Stress (psi) 2822.50 2759.58Max Stress (psi) 2822.50 2762.50
Yield Elongation (%) 14.21 15.87Break Stress (psi) 1644.66 1208.13
Modulus (psi) 48114.58 282562.50
Max Energy (in*lb/in3) 286.83 305.08
Max Elongation (%) 14.47 15.25TE Auto (%) 758.94 650.11
Conclusion
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.
Individual 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
References 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. <http://www.matweb.com/search/DataSheet.aspx?MatGUID=c35a0a3e740e424fad260a5da2c2b50a&ckck=1>.
Acknowledgements 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
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