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

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Presentation on theme: "Brett Braker MET496 April 28 th, 2011. Individual Performance Objectives Show the importance of temperature-controlled molding in thermoforming. Prove."— Presentation transcript:

1 Brett Braker MET496 April 28 th, 2011

2 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

3 Purpose Almost all of thermoforming industry uses amorphous materials Use molds that are not temperature-controlled Material options = Better quality parts

4 Material 50 High Density Polyethylene sheets 22.5 (MD) x 40 (TD) x Levant finish on top, smooth bottom °F forming temp, 330°F optimum 170°F ejection Density: lb/in 3 (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

5 Grid Layout Original Idea Penn College Printing Department Pat Bundra Screen Printing

6 Non Temperature-Controlled Mold Renshape 472 Medium Density Polyurethane Board (REN) Wooden base, machined Polyurethane core Exact same dimensions as aluminum mold x x 4.2

7 Renshape Cycle Bottom platen Material Build-up Stretching Material Properties

8 Renshape Cycle

9 Top platen Machine settings

10 Renshape Cycle Perfect cycle Rails too close Mold too deep Ovens too hot

11 Production-Style Run 10 parts Continuous cycle Measurements Temperatures Aluminum Jig Thicknesses 2 minutes after forming 24+ hours after forming

12 Temperature Measurements Mold Front Top Back Sheet temp before and after forming Room temperature Humidity All taken with infrared gun

13 Aluminum Jig Measurements x Corner 3-4 Height – x = h Jig thickness Aluminum blocks Meter stick height Dial calipers

14 Thickness 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

15 Measurement Formulas After jig measurements Match corresponding points (1-8, 6-3, 5-9, etc.) Take combination of both and subtract from jig dimension Y1 = – ( ) Y1 = Points show warpage Y1 shows shrinkage

16 Renshape Mold Production I.R. eye – 370°F Heating – 120 seconds Cooling – 180 seconds

17 Renshape Production Results

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21 Aluminum Mold Production I.R. eye – 370°F Changed to 360°F 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 – 200°F

22 Aluminum Mold Production Results

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26 Renshape vs. Aluminum

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32 Design Of Experiment

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34 Renshape Tensile Testing

35 Aluminum Tensile Testing

36 Renshape vs. Aluminum

37 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.

38 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

39 References Defosse, Matthew. "Thermoforming." Modern Plastics Worldwide World Encyclopedia Los Angeles, CA: Canon Communications, Print. Harper, Charles A. Handbook of Plastic Processes. Hoboken, NJ: Wiley-Interscience, Print. Illig, Adolf, and Peter Schwarzmann. Thermoforming: A Practical Guide. Munich: Hanser, Print. Peacock, Andrew J. Handbook of Polyethylene: Structures, Properties, and Applications. New York: Marcel Dekker, Print. "Sheet/Thermoforming Grade HDPE." Material Property Data. Web..

40 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

41 Questions?


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