Surface integrity in ultra-precision grinding of transparent ceramics

For high-performance optical applications, transparent polycrystalline ceramics are interesting materials because of the high thermal, chemical and mechanical resistance. However, due to its brittleness and hardness, the machining of these materials is difficult and the optical functionality is largely depending on the machining conditions as well as the material removal regime. Therefore, the goal is to generate damage-free surfaces through ductile regime grinding. The technology of choice is ultra-precision grinding which can be applied for complex geometries, but which influences the surface integrity in different ways. In the following experimental study, grinding results in terms of surface roughness and subsurface damage for fine-grained spinel are discussed.