| 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 material by heating the core part of the sheet to a temperature higher than the upper limit of the said range, and causing the outer, surface parts of the sheet to be at a temperature lower than the lower limit of the said range. After the temperature conditioning the material is thermoformed with rapid cooling of the core part, which cooling may be combined with reduction in thickness of the web or may take place after such reduction in thickness. The rapid cooling is through the said range and growth of crystals in the core part is controlled. |
