Abstract

Continuous process and apparatus form products from thermoplastic materials between top and bottom mold carriages. A flexible silicone rubber mold adhered to a fiber belt continuously moves around each carriage frame. A surface of desired shape on one rubber mold mates with the desired shape of an opposed rubber mold surface forming a continuously moving mold channel into which is fed hot thermoplastic material at moldable temperature. After discharging the molded plastic product from the moving mold channel, localized surface heat in the molds resulting from contact with hot plastic is removed from the belt molds by blowing cold air onto mold surfaces. Each carriage frame includes a back-up plate coated with low friction coefficient material over which slides a continuously moving belt mold. These slippery plates have numerous air-bearing holes feeding high pressure air between them and the respective moving fiber belt for reducing friction and wear. The fiber belts are guided and driven by a wide, central V-shaped toothed ridge or by twin, wide V-shaped toothed ridges along belt margins. These ridges fit into and mesh with corresponding toothed grooves of sprocket drive rolls, serving to maintain alignment of revolving mold belts. An electric drive motor, with or without torque-motor assistance, revolves both belt molds in unison maintaining their mating alignment. Electric screw jacks raise the top carriage, extend/retract grooved exit rolls, fine-tune alignment of revolving belt molds by adjusting grooved exit rolls and adjust the machine relative to the extruder.

Other References

• An article in the Dec. 1979 issue of "Modern Plastics" on continuous impression moldin