Improved mould design in metal injection moulding by combination of numerical simulations and experiments

Metal injection moulding combines thermoplastic injection moulding and powder metallurgy technologies to produce small and intricate metallic parts in a near net shape. The injection stage is of primary importance and the injection moulding of a metallic powder and plastic binder permits the desired shape to be obtained. A procedure is proposed for mould cavity design and optimal choice of injection parameters. This procedure is based on both numerical simulation by the finite element method and experiments allowing a primer choice and an update of injection moulding parameters. The powder segregation phenomena have been also investigated by experiments, moulding and simulation and an approach based on a biphasic flow approach has been proposed that permits powder segregation to occur during injection. Based on that approach, a three-dimensional finite element software has been developed and used for simulation. Experiments and numerical investigations on powder segregation have been carried out and results are presented that are in good agreement with experiments.