Superfinishing of Fine Ceramics

Influence of Machining Damage on Bending Strength

Abstract

The machining damage done to the surface of ceramics by superfinishing is investigated experimentally. The bending strength of the ceramics finished is measured. The influence of the grain size and the finishing conditions on the bending strength is investigated. The work materials used are alumina Al₂O₃ sintered under atmospheric pressure and Mn-Zn ferrite sintered under HIP. The results are as follows. Superfinishing is very effective in removing the machining damage and improving the bending strength of the ground ceramic. Using a finer grain under lower stone pressure makes it possible to remove the work material as chips by plastic deformation and decrease the machining damage on the surface. It is estimated that the bending strength is influenced by the median cracks which are formed under the bottom of the groove by active grains. It is possible to increase the bending strength, using the stone under the condition of glazing.