Effects of structural orientation on EDM properties of sapphire

Abstract

Precise machining technologies of advanced insulating ceramics are demanded in many industrial fields. Normally Electric Discharge Machining (EDM) utilizes for electrical conductive materials. Recently, insulating materials have been succeeded to machine with the assisting electrode method (AEM) that was proposed by authors. Some ceramics were still recognized as hard materials. Especially the high purity oxide ceramics of Al2O3 are difficult to machine for this method. Moreover single crystal Al 2O3 of sapphire (99.99%) is recognized as the hard machining material for the EDM method. In this paper, EDM of crystallographic planes on 3 different sapphires were carried out. The effects of the crystal orientation were discussed on the machining properties of sapphires.