Ejecting thermoset mouldings with gas - by feeding compressed gas to bores leading to all closed mould cavities until pressure there builds up, and releasing when mould opens

摘要

Thermosetting mouldings are demoulded by pressurised gas. Towards the end of the curing cycle and while the press is closed a gas is forced into at least one bore which extends to the surface of the mould impressions; the gas is fed in to form a gas cushion in each bore; the gas feed is interrupted and the mould is opened, so that the gas released ejects the moulding. ADVANTAGE - The arrangement eliminates the problems of moulding thermoset systems i.e. flow of shot into the spaces round ejector pins and interference with the movements of the pins unless their guide bores are regularly kept clear.