INTEGRATED FILLING, PACKING AND COOLING CAE ANALYSIS OF POWDER INJECTION MOULDING PARTS

Abstract

A coupled numerical analysis of the filling, packing and cooling stages of powder injection moulding (PIM) has been implemented. Finite element method/finite difference method methodologies were used in the filling and packing stages while Boundary Element Method (BEM) was used for the cooling stage. Using these methodologies, a numerical simulation program for the injection moulding process of PIM parts, PIMSolver was developed by taking into account the peculiar rheological behaviour of powder-binder mixtures. Specifically, the apparent slip phenomena at the mould wall and the yield stress were incorporated into the above analysis. The coupled analysis among the filling, packing and cooling stages was performed because the viscosity and slip phenomena of powder-binder mixture highly depend on temperature. In order to evaluate the significance of the coupled analysis and slip phenomena, several PIM experiments were performed using 316L stainless steel powders dispersed in a paraffin wax-polypropylene binder system. Using the examples of a U-shaped test specimen and an electronic package part, the importance of coupled numerical analysis for PIM parts and the significance of slip dependency of temperature during the coupled analysis were demonstrated.