Pulsed ultrasonic assisted electrical discharge machining for finishing operations

• A Pulsed Ultrasonic assisted EDM process has been proposed for finishing operations.
• The US vibration in the electrode can improve the surface roughness and homogeneity.
• A process close to PMD-EDM was induced by not completely cleaning the gap.
• The effect of the US in the finishing EDM process rests on the transmitted vibration.

Electrical Discharge Machining (EDM) is a non-conventional machining process specially suitable for manufacturing hard-to-machine materials or geometrically complex parts. Many investigations have been presented combining EDM with ultrasonic (US) vibration of the electrode, but most of them have been intended to enhance the material removal rate of the process. In this paper US assisted EDM process has been used in order to improve the surface roughness in a finishing operation. For that purpose a copper rod tool electrode and a 1.2344 tempered alloy steel workpiece have been used. A pulsed US assisted EDM mode (PUEDM) has been developed and compared with the current EDM process and EDM assisted with continuous US vibration (UEDM). The results show that PUEDM process can improve the surface roughness and homogeneity of the machined surfaces in finishing EDM operations.