SAETT ATT FRAMSTAELLA EN BEHAOLLARE

摘要

A method of producing a container of polyethylene terephthalate or similar thermoplastic material from a tubular blank of amorphous material. A mechanical forming element moves a transitional zone between amorphous (thicker) material and thinner oriented material stretched to flow during simultaneous elongation of the blank in the direction of movement of the transitional zone. The stretched and oriented material is heated to a temperature higher than the temperature of the material immediately before stretching. As a result, the internal stresses produced in the material during earlier stretching are relieved. Heating causes the length of the material in the direction of stretching also to be reduced. Each subsequent forming stage for shaping the container takes place at a temperature lower than the temperature at the immediately preceding forming stage.