Brett Braker MET496 April 28 th, 2011. Individual Performance Objectives Show the importance of temperature-controlled molding in thermoforming. Prove.

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

Questions?