Effect of Insulating Si3N4 Ceramics on Removal Rate by EDM with Piezoelectric Device

Abstract

 This paper describes the machining characteristics of insulating ceramics by EDM (electrical discharge machining) with a piezoelectric device. A piezo scanner that can carry out drive control independently in the X-, Y-, and Z-directions was used for the piezoelectric device. Using the Z-axis as the main axis, dual servo control with a motor drive was applied, with oscillation in the X- and Y-axes, and the effects of these oscillations were examined. In addition to adding these controls to the piezo scanner, the removal rate was considerably improved by independently controlling the gain of the up-and-down motion based on the electrical discharge state of the high-resistance surface. Furthermore, to transmit rotation to the oscillation tool electrode, a magnetic non-contact transfer drive was utilized. Using this combination of controls, we effectively improved the removal rate in micro-hole machining.