Continuous 3-D forming machine and endless flexible forming belts for forming three-dimensional products from thermoplastic materials

摘要

Continuous 3-D forming machine using upper and lower revolving endless, flexible, forming belts produces three-dimensional patterned products from heated thermoplastic material. The mold belts revolve synchronously in elongated oval paths around their respective carriages moving in opposed face-to-face relationship defining one or more travelling mold channels progressing from an entrance to an exit. Formable heated thermoplastic material feeds into the entrance, and attractive 3-D products proceed from the exit. Revolving mold surfaces are operated at least 25 DEG F. above room temperature, for example in a range of 110 DEG F. to 140 DEG F., for providing aesthetic surface qualities on products having content which may be foamed to densities in the range of about 0.9 to about 0.4. Thermoplastics in such travelling mold channels are appropriately chilled when differentials DELTA T in degrees Fahrenheit between mold surface temperatures T2 and temperatures T1 of heated entering thermoplastics are greater than T2: T1-T2= DELTA T>T2. Mold belts shown have silicone rubber molds bonded to five-ply plastic fabric and plastic resin backing belts sliding along slippery-plastic-covered platens having air-film lubrication and cooling of friction heat. Vacuum holds the revolving upper belt up against its overlying platen. Exit ends of carriages are shown extendable/retractable at least 25 inches for handling belts sized at 16, 18 or 20 circumferential feet. Removable bridges span gaps near extended exit ends of each carriage for supporting and guiding revolving mold belts travelling over these bridges.