TOWARDS A 3-D FINITE-ELEMENT MODEL FOR THE GAS-ASSISTED INJECTION-MOLDING PROCESS

The Gas-Assisted Injection Moulding process (GAIM) offers a number of advantages, which are almost without exception related to the negligib le pressure drop in the gas core of the moulded product. Accurate pred iction of the gas distribution inside GAIM products is, however, still a major problem to be solved. As gas penetration is governed by three -dimensional phenomena, one has to resort to numerical simulations to analyse the process. Therefore, a numerical model for GAIM simulations has been developed, based on a physical, rather than on an empirical approach. The model employs a pseudo-concentration method in order to avoid elaborate three-dimensional remeshing, and has been implemented in a finite element program. Simulation results for two-dimensional te st cases representing typical GAIM situations prove that the model cov ers most of the important aspects of gas injection. A pilot simulation for a simple three-dimensional mould demonstrates that the model is a ble to deal with three-dimensional GAIM. Further refinement of the mod el will mainly concern the implementation of faster and less memory-co nsuming solution methods.