Development of strip EDM

Electrical discharge machining (EDM) is a widespread machining method for the die and mold industry. This method can machine all conductive materials, including hard-to-cut metals, because the machining process uses electro-thermal energy without a cutting force. During EDM, discharge sparks remove not only the material of a workpiece but also the material of an electrode. This machining mechanism thereby causes electrode wear, which creates serious problems, including make-shape errors and low productivity. In order to overcome such problems, a new EDM method using a strip electrode (strip EDM) was developed in this study. Strip EDM uses a continuously applied strip electrode similar to the wire electrode in wire EDM. In the suggested strip-electrode method, a conductive strip moves on the electrode guide. The worn strip is removed, and a new one is supplied continuously. Therefore, the tool electrode acquires no wear during the machining process. This method uses a conductive strip that is made of brass. In the practical machining process, the strip EDM method was applied to EDM milling and EDM turning and their machining characteristics were compared with general EDM methods.