Metal injection moulding of thin-walled titanium parts for medical applications

Metal injection moulding (MIM) is an established technique for serial production of complex, mostly stainless steel parts. However, for other materials, especially for titanium parts, there is still the need for superior purity and enhanced surface quality. This paper describes recent advances at Fraunhofer IFAM to address the challenge of producing fit-for-purpose titanium MIM medical parts. Investigations have shown the effect of using very fine powders and mould surface finish: with polished moulds a very low surface roughness, <0·8 µm, was obtainable on the sintered part. Chemical and mechanical properties of the sintered parts are determined by complex interactions between sintering conditions, purity, particle size and binder components. Tests on the feasibility of moulding high aspect ratios, wall thicknesses <200 µm and special features such as a fine internal threads and hexagon headset structures are also reported.