ON THE HEAT-BALANCE DURING DOUBLE-GATED, MODULATED-PRESSURE INJECTION-MOLDING

Double-gated, modulated-pressure moulding provides orientation of mole cules or fibres so that the properties of materials can be controlled during processing. A numerical method for estimating the duration of o scillating flow under a preset pressure amplitude based on the balance of viscous heating and loss to the mould wall is described; This firs t attempt to quantify an extremely complex process allows the effects of moulding parameters on solidification to be deduced and the experim ental array reduced. The predictions are compared with experimental re sults for high and low thermal diffusivity materials. (C) 1997 Elsevie r Science Ltd.