Development of strip EDM

Abstract

In this research, a strip-electrode system was developed to overcome the problem of electrode wear in electrical discharge machining (EDM). In general EDM, electrode wear causes shape errors to the workpiece. High production costs must be incurred to resolve such errors. Strip EDM makes efficient use of the electrode, eliminating the need for additional machining processes or methods to resolve shape errors. The strip electrode moves continuously along the electrode guide, creating the same conditions found in wire EDM, where the worn electrode is immediately replaced with a new one. The strip slides along the surface of an electrode guide in the strip EDM system. During the actual machining process, the entire guide system moves along the tool path. The electrode guide acts like a block electrode in general EDM and the strip acts like the surface of an electrode. This effectively eliminates concern about tool electrode wear during machining. Using the machining system developed, three major applications were tested in this study: milling, turning, and V-grooving. When the strip machining system was applied to ED-milling, grooves and curved structures were fabricated without having to compensate for electrode wear. Strip EDM was applied to turning and the results promise excellent accuracy at a high machining speed. V-grooving to make several types of cutting angles was also investigated and the strip-EDM method was successfully used to cut various shapes from a stainless steel workpiece.