Powder Injection Molding (PIM) for Low Cost Manufacturing of Intricate Parts to Net-Shape
Abstract : Powder Injection Molding (PIM) is a low cost manufacturing process that produces very complex parts to net-shape in a wide variety of materials and unique alloys, including superalloys, stainless steels and carbides, resulting in minimal secondary and assembly operations. PIM offers significant cost savings, increased design and materials flexibility, increased possibility of miniaturization, high mechanical properties, good surface finish and high speed production. The activities and expertise in powder metallurgy as well as in process numerical modeling related to powder injection molding at the Industrial Materials Institute of the National Research Council of Canada (NRC-IMI) and at Maetta Sciences, a company that has research and development facilities at the NRC-IMI, will be presented. Selected solutions and examples realized by NRC-IMI and by Maetta Sciences using respectively their high pressure and their scalable PIM platforms will be presented and described. Potential applications for the military, transportation and aerospace sectors will be highlighted.
Metal injection molding: 3D modeling of nonisothermal filling
A three-dimensional transient finite element flow analysis code that includes inertia and free surface modeling is used to predict uniform (axisymmetric) and nonuniform (nonaxisymmetric) filling patterns in 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.
RHEOLOGY OF CERAMIC INJECTION-MOLDING FORMULATIONS
On etudie la rheologie de diverses formulations a base de poudres de silicium et de polymeres et cires thermoplastiques en vue du choix d'un systeme de liant approprie pour des essais de moulage par injection