SECONDARY FORMING METHOD OF DIAMETRICALLY EXPANDED SOCKET HAVING ANNULAR GROOVE

摘要

PURPOSE:To rationalize the secondary forming of the diametrically expanded socket remarkably and obtain a product good in accuracy at a low cost by a method wherein a pipe end inserted into a forming mold constituted as an intrusion type forming mold for secondary forming is molten and configured by a heating means to make the pipe end display a thermoelastic function. CONSTITUTION:When the intrusion forming of a fusion forming section 12a is finished, heating devices 8d, 9b are switched so as to hold a conditional temperature in the area of thermoelastic condition and an outer mold 9 at the socket side is released into a direction A. When the temperature of the fusion forming section 12a is arrived at the temperature of thermoplastic condition, a core main body 6 and a slidable core 8 are moved into directions B, C simultaneously to release the section 12a. The forming section 12a deformed already is restored immediately and the internal surface of the opening of the fusion forming section 12a is regulated by a large diametral forming section 6b of the core main body. Under this condition, heating of the core main body 6 and a split mold 10 is stopped or cooling medium is circulated thereby hardening the resin positively.