Abstract: Polypropylene and ZrO2 microstructures are fabricated respectively by polymer and powder micro injection molding under different process conditions. Microcavities in silicon mold insert are manufactured by inductively coupled plasma (ICP) etching process. The effects of process conditions and silicon mold on the filling performance, dimensional accuracy and surface quality of microstructures are detailedly investigated. Inappropriate injection conditions will induce many defects such as underfill, rough surface and hollow. Microstructures can be filled completely by raising mold temperature and injection pressure and by vacuuming the mold before injection, and the latter can also improve the surface quality of microstructures. The roughness of etched silicon mold surface is about 0.31 μm. If microcavities are filled completely, the effect of injection parameters on the surface roughness of polymer and ceramic green microstructures is neglectable. They have approximate roughness with silicon mold. Sub-micron ZrO2 powder can improve the surface roughness of sintered ceramic microstructures.

Key words: Micro injection molding, Micro-structure, Silicon mold