Electrical Discharge Truing of a Vitrified Bonded Superabrasive Wheel with Electrical Conductivity

Abstract

With its high grit retention and easiness to true and dress, the vitrified bond is widely used as a bond material for cBN and diamond grinding wheels. By giving electrical conductivity to the vitrified bond, application of electrical discharge trueing/dressing and detection of a workpiece position by electrical contact sensing will become possible. And moreover, application of the vitrified bonded wheels to various types of electro-assisted grinding processes (electrochemical or electro discharge assisted methods) is expected. In this study, vitrified bonded diamond segments with electrical conductivity were manufactured experimentally by mixing the fine copper powders in the vitrified bond matrix. As a result of investigation into the electro discharge trueing performance in the die sinking and wire electro discharge machining, it was found that a vitrified bonded wheel could be formed by electro discharge machining only because the bond was electrically conductive. In addition, the electro discharge complex grinding utilizing electric discharge machining was applied to the PCD cutting tool materials using the electrically conductive vitrified bonded wheel, and confirmed that the grinding could be continued for a long time maintaining a stable grinding force.