Multi-component microinjection moulding-trends and developments

Abstract

With standard microinjection moulding becoming more and more established in practical manufacturing, special variants are attracting increasing attention. Especially, the approaches on multi-component microinjection moulding are worth mentioning: As handling and assembly are difficult procedures especially in microtechnology, methods to reduce mounting efforts are of high economic importance. By merging of shaping and mounting procedures in one step, economic progress as well as new material combinations can be obtained. An interesting approach for the fabrication of metal (or in principal, ceramic) microcomponents is the combination of insert injection moulding and metal deposition by electroforming. First, an electrically conductive base plate is produced by injection moulding of conductively filled polymers. In a second injection moulding step, microstructures consisting of insulating plastics are mounted on these plates. The quasi-infinite conductivity gradient allows controlled electroplating starting at the base plate only so that defect-free metal microcomponents can be achieved. As a further variant of microinjection moulding, the development of the so-called MicroPIM process facilitates a large-scale series fabrication technology for metal and ceramic microcomponents. Combined with multi-component technology, an interesting new approach for micromanufacturing is obtained, i.e. the realisation of magnetic/non-magnetic or conductive/non-conductive material combinations by two-component MicroPIM. But, also the combination of different mechanical properties like hard/tough pairings is possible.