Material Removal in Orthogonal Cutting of Ceramics by Superimposing Ultrasonic Vibration on the Tool

Abstract

It was found previously that material removal in orthogonal cutting of ceramics was characterized by the trajectory of a macro crack: at the beginning it unstably extends downwards by some distance from the region near the tool tip, then re-extends after a pause, and finally, being accompanied with material crushing ahead of the tool rake face, turns upwards to emerge out at the free surface.
In this study the ultrasonic vibration cutting of mullite and glass ceramics (Macor) was carried out orthogonally to hasten the material crushing which helps to stop an undesired extension of the macro crack. The main results obtained are as follows.
(1) The material crushing was accelerated by repeated impacts of the ultrasonically vibrating tool on the work being cut. A large part of the material removal was done by this crushing, and craters on the cut surface made by macro crack extension become shallow.
(2) The material crushing was facilitated more by shorter time repeated impacts, which can be attained by adopting the proper values of frequency and amplitude of the tool vibration and the feeding velocity of the work.