CPM Seminar

In this presentation, a three-dimensional finite element flow analysis method is described in the context of the powder injection molding process. Details of the governing and constitutive equations, finite element formulation and numerical implementation will be presented. Applications will demonstrate the capabilities of the method. More precisely, predictions of uniform (axisymmetric) and nonuniform (nonaxisymmetric) filling patterns will be presented for a thick-walled tool with a diaphragm gate. The simulation for a metal injection molding compound, which is strongly influenced by thermal effects, predicted several observed flow patterns: initial annular free surface flow (jetting), bypass and folding flow to form surface defects, and the transition from uniform (axisymmetric) flow to nonuniform (nonaxisymmetric flow) with increasing fill time and lower temperatures. Simulations of filling through a thicker diaphragm gate showed jetting and the associated problems were eliminated. Simulations also demonstrate the effects of filling time, mold temperature, inertia, yield stress, and wall slip on filling patterns, particularly the processing conditions that separate regions of uniform and nonuniform flow. Finally, the influence of the material compressibility during the packing phase is simulated and comparisons between predictions and experiments are presented.

Thursday, April 11th 2002, 16:00
Ernest Rutherford Physics Building, Keys Auditorium (room 112)