A survey of servo-drive control schemes for electric discharge machining (EDM)

The electric discharge machining process is a very useful, economic and reliable process to machine extremely hard and brittle materials which cannot be machined by any of the conventional processes. It is based on the principle of erosion of metals by an interrupted electric spark. To ensure stable and effective machining, the spark-gap between the two electrodes (the tool and the work-piece) must be maintained at the desired level by servo-controlled electrode feed mechanism. The present paper reviews the various schemes for controlling the servo-drive mechanism for achieving better performance of the machining process.