Powder injection molding of free-formed micro test specimen

Although micro powder injection molding (MicroPIM) represents a strong technological task it becomes even more difficult in case of free-formed geometries. A challenging example are micro-sized test particles. Such artificial specimen are required for modelling and simulation of wear effects caused by manufacturing debris|swarfs occuring in e.g. journal bearings or combustion engines.The free-formed geometry was derived from a real manufacturing swarf previously characterized by 3D- CT. Micro mold insert design incorporating the free-formed surfaces was comprehensively simulated and realized by milling and discharge machining. For the first time in MicroPIM, specially tailored feedstocks containing 42CrMo4 steel powders were applied. The related molding, debinding, and sintering procedures had to be developed, too.The damage potential of the test particles was evaluated based on trials using journal bearing and shift valve test rigs. Thereby, it could be ascertained that the artificial swarfs will allow for development of standardized wear test procedures.