Multi-Component Micro Injection Moulding – Trends and Developments

V. Piotter(a), G. Finnah(b), J. Prokop(a), R. Ruprecht(a), J. Hausselt(a)
a: Forschungszentrum Karlsruhe, Institute for Materials Research III, P.O. Box 3640, 76021 Karlsruhe, Germany
b: Robert Bosch GmbH, Waiblingen, Germany

Abstract

With standard micro injection molding becoming more and more established in practical manufacturing, special variants are attracting increasing attention. Especially the approaches on multi-component micro injection moulding have to be mentioned: As handling and assembly are difficult procedures especially in micro technology, 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) micro components is the combination of insert injection molding 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 micro components can be achieved. As a further variant of micro injection moulding, the development of the so-called MicroPIM process facilitates a large-scale series fabrication technology for metal and ceramic micro components. Combined with multi-component technology, an interesting new approach for micro manufacturing is obtained, i.e. the realization of magnetic/nonmagnetic or conductive/non-conductive material combinations by two-component MicroPIM.