non metallic materials and processes

MASS PRODUCTION OF INJECTION-MOLDINGChris Miller, Collin Swick, David Mason, Greg Weaver, and Jordan Hites

INTRODUCTION

The scenario we were presented was one where our company is losing market share because of the inability to turn out a good product and management has come to our department to redevelop the product from the ground up. The tasks assigned to us included the planning, designing, construction, mass production of, and testing of an item. The production of the item, we decided upon, would need to produce at least 100 pieces of said item by using an injection molding machine. These produced items would then be considered for retail sales.

INITIAL IDEA FOR RETAIL

Our initial idea for retail was to mass produce poker chips. We chose poker chips, because we thought it would be something that we could not only produce efficiently but also use after we had produced them. Additionally, poker chips are used in abundance around the world, not only by casinos, but by everyday consumers, organizations, families, etc. This makes the rationale behind our idea for mass producing poker chips good because there is plenty of room in the market for more chips to be produced.

INITIAL IDEA FOR RETAIL

We decided to use a combination of different plastic polymers to achieve the qualities of most regulation-size plastic poker chips that are produced by companies in the market. In order to achieve the desired qualities, we would have to mix, produce, and test the different combinations using a hardness tester and a Tinius Olsen machine. The mold we decided to produce for the production of our poker chips would be made out of aluminum, and the desired approximate dimensions of the poker chips we would produce would be 40mm in diameter, 3mm in thickness, and 5-7g in weight.

INITIAL DRAWINGS

Design #1 Design #2

PROJECT PLANNING

MECHANICAL DESIGNFinished Mold with Sandblasted Pattern

Finished Poker Chips

INITIAL MECHANICAL DRAWINGSPoker Chip Design in CATIA

Initial Mold Design in CATIA

FINAL MECHANICAL DRAWINGSFinal Chip Design in Pro Engineer

Final Mold Design in Pro Engineer

INITIAL PRODUCTION PROCESS

INJECTION PROCESS

Material used 60% polyethylene / 40% polypropylene

Software Used/Electronics Used Initial drawings: CADD, Windows Picture and Fax

Viewer, & Snagit Project planning: Microsoft Office Project & Snagit Mechanical drawings: CATIA, Snagit, Pro Engineer Mold designing: Corel Draw

TOOLING AND MACHINING & MATERIAL REQUIRED TO MAKE CHANGE

Tooling and machining Mold machining: Delta horizontal band saw,

Delta drill press, Trump vertical mill, Cincinnati Milacron Sandblaster

Mold designing: Universal Laser Systems laser engraver

Production: Cincinnati Milacron injection molder & KUKA KR3 robot

Material 5”x4”x0.625” aluminum stock Polyethylene – Virgin pellets, D=1380 kg/m3

Polypropylene – Virgin pellets, D=0.9 g/cm3

TESTING PROCESS

Hardness Testing Average hardness number of 60% polyethylene

and 40% polypropylene mixture = 103 Young’s Modulus

For 60% polyethylene, 40% polypropylene mix:

A THOROUGH ANALYSIS OF THE PROJECT

The aluminum mold we produced for the production of our plastic chips was milled with great accuracy and precision. Additionally, the sandblasted pattern design was added to the mold very well. Likewise, the settings we finalized on using for the injection molding machine were very precise as well. This led to the production of poker chips that had very little flashing problems and had surfaces that were smooth and flat, with no noticeable inconsistencies.


There were some things that could have been done differently, however, if we were to complete the entire process for mass producing plastic poker chips again. First, a better followed timeline and schedule for the different phases of the poker chip development process would have led to our ability to produce even more poker chips by the stated deadline. Another thing that was not ideal in our poker chip development process was that we were only able to test for hardness and tensile strength values. If we would have been able to test for compression, shear, and other values, it would have given us a more complete tool to evaluate our final product.


Our group found this project to be very involving and a great learning experience. We found its weaving of product manufacturing, solid modeling, and quality assurance into nonmetals to be not only an educational but very practical endeavor. We would highly recommend the repetition of this project for at least the next few following years.

RECOMMENDATIONS TO MANAGEMENT The following are the settings used on the injection molding machine

to optimize the mass production of regulation-sized poker chips. Clamp Close Fast 3.00 Clamp Close Slow 1.20 Clamp Open Limit 6.00 Open Speed Fast 2.75 Actual Clamp Position 6.02 Tonnage 33.00 Ejector Forward Speed 3.00 Ejector Dwell Timer 5.00 Retract Speed 2.10 Nozzle Temperature 475.00 Zone 1 Temperature450.00 Zone 2 Temperature450.00 Zone 3 Temperature440.00 Injection High Time 4.00 Pack Time 3.00 Hold Time 4.00 Cooling Time 12.00 Shot Size 0.50

FUTURE CONSIDERATIONS

For future considerations of a project of this magnitude it would be best to perhaps actually incorporate robots into the production process to see how it would affect total cycle times. While our cycle times were relatively low when the injection molding machine was running effectively, they most likely could have been vastly improved with the use of robots. One way the robots could have been utilized would be to have them remove the completed chip part as the machine was moving out to wait for another cycle to begin. This would have allowed for the chip to be removed more quickly and for another cycle to begin, allowing production numbers to increase.


Additionally, the production process could have been improved, and production times lowered, if we had produced a poker chip mold that included space for two chips to be made each cycle. There was sufficient room on the piece of aluminum to mill another poker chip cavity, therefore two could have been produced for each cycle the injection molding machine made.


Another future consideration for this type of project would be to possibly experiment with limited production runs of more exotic nonmetallic materials. With the use of more exotic nonmetallic materials possibly mixed with traditional plastic polymers, as opposed to only the use of traditional plastic polymers, it is possible to have created a mixture that would have allowed for lower machine temperatures and smaller pack times. This possibly would have resulted in smaller cycle times and the production of more chips and at more efficient cost ratios.

FINISHED POKER CHIPS

APPENDIX

Hardness Tester Tinius Olsen Machine

non metallic materials and processes

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