State of the art in micro forming and investigations into micro deep drawing

Micro forming is an appropriate technology to manufacture very small metal parts, in particular for bulk production, as these are required in many industrial products resulting from microtechnology. This paper gives a review of the state-of-the-art in the micro forming of metals. The problems occurring in the miniaturisation of forming technologies such as micro massive forming and micro sheet metal forming are described. One of the problems is scaling effects, which e.g. occur in tribological aspects such as the friction coefficient, which increases with decreasing specimen size. Experimental investigations into micro deep drawing were carried out and the limit drawing ratio was determined. Furthermore, it was found that the friction coefficient in micro deep drawing at the flange and at the die radius are unequal and depend on the applied pressure. Scaling effects not only appear within the process but also must be taken into account in all other areas of the forming process chain, finally demanding new solutions, especially on tool manufacturing and machine concepts. The laser is an innovative tool, which can be used for rapid tooling, building up millimetre high free-standing structures, or for the generation of near net shape structures by laser erosion. The laser technique represents an auspicious tool for the tool manufacturing industry to exploit the inherent potential of micro forming in the future.