Towards a 3-D finite element model for the gas-assisted injection moulding process

The gas-assisted injection molding process (GAIM) offers a no. of advantages, which are almost without exception related to the negligible pressure drop in the gas core of the molded product. Accurate prediction of the gas distribution inside GAIM products is, however, still a major problem to be solved. As gas penetration is governed by 3-dimensional phenomena, one has to resort to numerical simulations to analyze the process. Therefore, a numerical model for GAIM simulations was developed, based on a phys., rather than on an empirical approach. The model employs a pseudo-concn. method in order to avoid elaborate 3-dimensional remeshing, and was implemented in a finite element program. Simulation results for 2-dimensional test cases representing typical GAIM situations prove that the model covers most of the important aspects of gas injection. A pilot simulation for a simple 3-dimensional mold demonstrates that the model is able to deal with 3-dimensional GAIM. Further refinement of the model will mainly concern the implementation of faster and less memory-consuming soln. method