Ultra-precision grinding of polycrystalline transparent ceramics

Polycrystalline transparent ceramics are an interesting material when optical applications demand high thermal, chemical and mechanical resistance. Due to the material characteristics, the grinding and polishing of these brittle hard materials is challenging. Ultra-precision grinding is a technology to manufacture surfaces with high quality and to reduce the necessary efforts for polishing. Therefore, in this paper results on the influence of the dressing, grinding and tool parameters on the resulting surface roughness and surface integrity when grinding polycrystalline transparent ceramics are shown. The influence of different dressing conditions, different diamond grain sizes, different depth of cut and different feed rates were investigated. The ground surfaces were analysed by white light interferometer, SEM and AFM. Depending on the parameters, roughness values in the range of Sa = 5 nm can be achieved.