Improving EDM Process Efficiency by Ultrasonic Vibrations

Among the newly developed non-conventional machining process, Electrical Discharge Machining (EDM) is the most popular because of its large industrial applications. EDM is a thermal machining process, which is capable of machining any electrical conductive material irrespective of its hardness and strength. In the last decade many attempts have been made to improve the performance of EDM. This paper deals with the improvement of EDM process by applying ultrasonic vibrations to the tool electrode. Studies have indicated that EDM operation with vibrating tool electrode allows deeper penetration and higher feed rates. This is especially useful during finishing operation, where machining time is reduced with the surface quality of workpiece unaffected. The modified EDM process is well adapted to the production of very intricately shape electrodes. Other major advantages of this process include the reduced recast layer, higher machining rate, low thermal residual stresses, and better metallurgical properties of workpiece. Analysis shows that improved dielectric fluid flushing is responsible for most of the advantages achieved. In ultrasonic assisted EDM process, what seems to be more important is the ability of working without instability, particularly when the gap is narrow.