Rapid-Tooling of Bunched Electrode for EDM

A bunched electrode for Electrical Discharge Machining (EDM) is formed by bunching numerous cell electrodes as a whole and allows better flushing to facilitate removal of more heat and debris produced during machining. This paper proposes a rapid tooling method for preparing bunched electrodes with desired end-face. A specially designed apparatus, which sits on an XY worktable of a CNC machine tool, is employed to hold the pre-bunched with flat end-face. By using a protrusion pin which is fixed on Z-axis, the heights of each cell electrode are protruded one after another according to a CNC program, which is generated by CAD/CAM software. The end-face of the bunched electrode approximates the ideal end-face of the designed 3D model by adjusting the Z positions of each cell electrode. By using this method the cost and time for electrode preparation are dramatically reduced as compared to that made by traditional cutting method. An investigation on 3D cavity machining of bunched electrode was conducted. The result gives a solid verification of the feasibility of using bunched electrode into roughing process of EDM.