Effect of Finish of the Cutting Edge on the First Stage Wear of Ceramic Tool

On Edge Roughness by Wear

Abstract

Application of ceramic tools is limited at present, because ceramics are comparatively weak against mechanical and thermal shocks. The wear mechanism of ceramic tools is also different from that metallic tools.
In this study, theoretical and experimental investigations on the relation between the roughness of initial cutting edge and that of worn cutting edge with alumina-based ceramic tools have been made.
The change of roughness of cutting edge at the initial stage of wear has been analyzed theoreticaly under such assumption that the wear of ceramic tool at the first stage of cutting is caused by cleavage and separation of alumina grains. And the result of the theoretical calculation has been confirmed by the orthogonal cutting tests of a steel.
The main findings are as follows :
(1) The experimental results on the behaviour of the roughness of cutting edge as the tool wear proceeds coincide qualitatively with those calculated.
(2) The roughness of worn tool edge becomes to be almost constant regardless of its initial state of finish, and the final value of roughness seems to be related with the grain size of alumina.