An overview of technology and research in electrode design and manufacturing in sinking electrical discharge machining

Abstract

Electrical discharge machining (EDM) is one of the earliest non-traditional machining processes, based on thermoelectric energy between the workpiece and an electrode. In this process, the material is removed electro thermally by a series of successive discrete discharges between two electrically conductive objects, i.e., the electrode and the workpiece. The performance of the process, to a large extent, depends on the material, design and manufacturing method of the electrodes. Electrode design and method of its manufacturing also affect on the cost of electrode. Researchers have explored a number of ways to improve electrode design and devised various ways of manufacturing. The paper reports a review on the research relating to EDM electrode design and its manufacturing for improving and optimizing performance measures and reducing time and cost of manufacturing. The final part of the paper discusses these developments and outlines the trends for future research work.

EDM machinability and surface roughness analysis of INCONEL 600 using graphite electrodes

“…Nevertheless, one single electrode material does not exist for all cases. The general rule indicates that metallic electrodes should be applied for low temperature alloys and graphite electrodes for high ones, but some exceptions also exist [10]. Earlier experiences showed that some materials are more suitable than others, depending on the material of the part, the generator, and the desired results.…”

Effect of electrode material on electrical discharge machining of tool steel surface

“…Previous research has shown that the quality of the machined surface is determined primarily by the pulse current and the pulse-on duration time [5][6][7][8][9][10][11][12][13][14][15] but few literatures studied the effect of electrode material [16][17][18][19][20][21][22][23]. Accordingly, the current study is based upon these two parameters, and specifies pulse currents of 15, 30 and 50 A with pulse-on times of 20, 100, 180 ls.…”

Austenitic steel surface integrity after EDM in different dielectric liquids

“…The current intensity growth causes the surface quality deterioration [22,25]. The extended pulse duration reduces the energy density (which improves surface quality by reducing surface roughness) of the discharge spots by expanding the plasma channel and, as a consequence, the material removal rate decreases and the tool electrode wear is reduced [12,22,23]. Tool wear, which is determined by tool electrode material properties, has a significant influence on the EDM machining accuracy.…”

“…Tool wear, which is determined by tool electrode material properties, has a significant influence on the EDM machining accuracy. The tool electrode is removed during the EDM process simultaneously by generated sparks, causing a characteristic corner and end (radial and axial) working electrode wear [12,20]. It is also worth mentioning that the melted electrode material can diffuse to the workpiece surface layer.…”

“…In EDM-sinking, material removal takes place as a result of the occurrence of a plasma channel (erosion effect) between the tool electrode and the workpiece surface, separated by dielectric liquid [2,12]. In each pulse, the machining material is melted and evaporated during each discharge occurring at a single location [19].…”