A theoretical model of surface roughness in ultrasonic vibration assisted electrical discharge machining in gas

A new machining method, named "Ultrasonic vibration assisted electrical discharge machining" (UEDM) in a gas environment is proposed in this paper. It is shown that ultrasonic assisted electrical discharge machining can be achieved well in a gas medium. The tool electrode is made of a thin-walled pipe, and the high pressure gas medium is supplied from inside. During machining, ultrasonic vibration of the workpiece can improve the machining process. A theoretical model to estimate the roughness of the finished surface has been developed. AISI 1045 steel and copper are selected as the workpiece material and electrode material respectively. Experiments have been carried out, and the results show that the roughness of finished surface increases with an increase in the discharge voltage (Ue), the discharge current (Ie) and the pulse duration (tS ).