Continuously moulding thermoplastic sheet - where machine grips sheet sides, heats, moves sides together to relax, deep draws and cools

摘要

Thermoplastic sheet or film is moulded while stretched and heated; the material is gripped at two opposite ends by a carriage while being heated, the carriage tracks move together after heating, the material tension is then released all round, and it is finally deep-drawn under pressure in conventional manner. Process can be mechanised, film can be blown first, method permits max. use of a hinged frame and hence min. expansion with deep areas.