METAL FEEDSTOCKS FOR ISOLATED MICRO PARTS MADE BY PIM

摘要

Micro PIM represents one of the future mass production processes for micro parts and is a topic of current research and investigation. Reduction of finishing is an important objective and the fabrication of isolated micro parts is a crucial requirement to reach this aim. For small parts good surface quality and small grain sizes after sintering are important. Thus, fine powders with small particle size have to be processed. To support the tool concept for isolated production, feedstocks with organic binders based on thermoplastic materials and waxes were developed. They provide low viscosity for mold filling down to the micrometer range and sufficient mechanical strength for deformation free demolding. After measuring the rheological feedstock data micro parts were produced by powder injection molding. The green parts were debindered chemically, using an organic solvent, and by thermal degradation before sintering. This paper presents results of feedstock development, tool concept, and production of > 1000 gearwheels with sintered diameter ～750 μm made of 17-4 PH stainless steel and WC/Co hard metal.