August 2009
A prototype can help you to see whether your invention works, to identify ways to improve its appearance and function, and to communicate it to the world of business and law. A prototype made of plastic is attractive and affordable, and can be made quickly. Mr. Andrew Nehrt (812-522-4433, proformplastics@verizon.net) of Pro-Form Plastics, Inc. (manufacturer of heavy-gauge [.03-.5" thick] molded plastics, non-metallic material [foam, felt, plastic, etc.] cut by steel-rule die, and customized wood shipping containers) spoke to us about the different designs, methods, plastics, and tools he uses to build prototypes. The method of thermoforming uses a vacuum to fit a rectangular sheet of heated plastic (3x4' to 5x9') to a mold of a product part (remember the Vac-u-form toy from years ago?). Before being fit to a deep mold, the plastic is stretched with a felt-covered plug. Plastic shrinks while cooling on the mold, so designing the mold with at least 2 degrees of draft...