This study investigated the electrical discharge machining characteristics of single crystal silicon carbide (SiC) using an inductor-capacitor (LC) pulse generator. It was found that the physical phenomena and machining performance differ significantly from those of metallic materials machined using conventional pulse generators. The short discharge current pulse generated by the LC pulse generator has a higher rising speed, resulting in a higher removal efficiency than that achieved using a conventional RC pulse generator, even when the discharge duration and peak discharge current are the same. Increasing the discharge energy caused the material removal mechanism of SiC to change from dissociation to spalling, leading to a material removal rate higher than that of steel. Using the LC pulse generator, the material removal rate was insensitive to the distance between the discharge locations and the ground. Based on these fundamental findings, a new machining system was developed that combines the twin-electrodes method, in which one tool electrode, the SiC workpiece, and the other tool electrode are connected in series, with the LC pulse generator. This enables dual discharges to be ignited simultaneously. Furthermore, a minimal and constant potential drop can be maintained in the SiC between the twin electrodes, regardless of the machining depth. Consequently, the material removal rate is significantly higher than with conventional EDM methods using a single tool electrode. • LC generator gives higher material removal rate (MRR) due to faster current rise and higher initial current density. • At high energy, SiC’s high resistivity causes strong heating and spalling, raising its MRR above steel. • At low energy, SiC melts instead of spalling, reducing its MRR compared with steel. • LC generator keeps MRR constant since induced electromotive force stabilizes current despite resistance changes. • Twin electrodes with the LC generator stabilize SiC slicing and increase its MRR at any machining depth
Jiang et al. (Fri,) studied this question.