Dry electrical discharge machining for deburring drilled holes in CFRP composite

Abstract

Dry electric discharge machining (EDM) is an evolving technology that uses gas as a dielectric instead of liquids like oil or deionized water. Dry EDM reduces machining costs and environmental hazards. Most studies on dry EDM deal with steel as the workpiece. Hence, this study investigates a dry EDM technique for the removal of burrs in drilled holes in CFRP composites. Oxygen and air was used as the dielectric medium, and the results were compared with a previous study on oil EDM. The material removal rate increased significantly with the capacitance, voltage, and gas pressure in both dry EDM and oil EDM. Positive tool polarity produced a higher material removal rate (MRR) than negative polarity in both cases. Compared to conventional oil EDM, using oxygen as a dielectric showed nearly three times better MRR, and that with air was two times better. Moreover, in dry EDM using oxygen as dielectric exhibited better performance than using air as dielectric. This study revealed that the dry EDM is more effective than that of oil EDM as a deburring technology.