Measurement of Burr Removal Rate and Analysis of Machining Parameters in Ultrasonic Assisted Dry EDM (US-EDM) for Deburring Drilled Holes in CFRP Composite

Abstract An ultrasonic assisted dry electrical discharge machining (US-EDM) process in a gaseous fluid medium was proposed to remove the burrs formed on the exit region of a drilled hole. In preliminary experiment, three different electrode tools (copper, brass, and aluminum) were utilized. In secondary experiment, US-EDM and dry-EDM were compared and performed using the copper tool. US-EDM parameters, such as capacitance (C), pulse-on time (T ON ), and vibration amplitude (A p-p ) were considered as functions of the predicted burr removal rates (BRRs) model. Based on signal to noise (S/N) ratio analysis, machining parameters C = 10 −2  µF, T ON  = 150 µs, and A p-p  = 4.919 µm provided the optimal BRR. The BRR was affected the most by capacitance, followed by pulse-on time and ultrasonic vibration amplitude. The copper tool provided a higher BRR than other tools. US-EDM is considerably effective when T ON is low and the performance of US-EDM is better than that of Dry-EDM. Scanning electron microscopy (SEM) analysis showed that the US-EDM method created a heat-affected zone surrounding the machined surface of the deburred exit hole in range of 200 µm–500 µm.