METHOD OF SHAPING PRODUCTS MADE OF HDPE OR PA, PARTICULARLY SPATIAL SHAPING OF HDPE OR PA TUBES, AND A DEVICE FOR PERFORMING IT

摘要

The invention relates to a method of shaping products made of HDPE or PA, particularly spatial shaping of HDPE or PA tubes, in which HDPE or PA semi-finished product is shaped. A semi-finished product from HDPE or PA is first heated to temperature T close to melting temperature T_g of the material so that the material remains in a solid state, T the semi-finished product made of HDPE or PA is left at this temperature for time period t₁ required to obtain plasticity and to disrupt completely or partially the crystalline or semi-crystalline structure of the HDPE or PA material and for relaxing the internal tension of the HDPE or PA material and for restoring the amorphous or partially amorphous state of the material, whereupon the HDPE or PA semi-finished product is inserted into a shaping fixture and the temperature of the HDPE or PA material gradually decreases to ambient temperature.;The invention also relates to a device for performing the method.