Method of manufacture of a thin wall made of thermoplastic material crystalline

摘要

A method for manufacturing thin- walled articles, for example cups and plates, by thermoforming a sheet of crystalline thermoplastics material which has a critical crystalline melting temperature range. The method includes temperature conditioning the sheet for thermoforming, and the conditioning comprises developing a preliminary temperature profile across the sheet such that the core part of the sheet is at a temperature lower than the said range, the outer surface regions of the sheet being at a still lower temperature. A final temperature profile for thermoforming is developed by reheating the outer surface regions to a temperature such that those regions become at least elastically deformable, the core part being kept in an elastically deformable state at a temperature lower than the said range.