Manufacturing of multi-functional micro parts by two-component metal injection moulding

Several metals and alloys can be used to enhance the mechanical and physical properties of micro parts and components for micromechanical, micro-chemical or sensor applications. Such parts can be produced in series by the powder metallurgical process of micro metal injection moulding (mu-MIM). This paper describes a novel manufacturing route for metallic multi-material micro components, two-component micro metal injection moulding (2C-mu-MIM). Similar to two-colour injection moulding of plastics, the process allows the integration of multiple functions in a micro part by simultaneously injecting and joining two materials in one mould. Net-shape parts with solid material interfaces are obtained. In this paper, the 2C-mu-MIM process is exemplified for the combination of a non-magnetic and a ferromagnetic stainless steel (316 L and 17-4PH). It is shown that intact material interfaces of less than 500x500 mu m(2) can be achieved by careful selection and tailoring of metal powders, injection moulding and co-sintering parameters.