Abstract
This paper describes a new method of surface modification by EDM to create a hard surface on a workpiece. When a metallic material that makes a hard carbide is used as an electrode in EDM, a hard layer can be made under certain conditions. The process begins with electrode wear by heat of EDM. Then the worn electrode material becomes a hard carbide. The carbide piles up on the workpiece and becomes a layer. A layer formed by two or more electrical discharges has the problem that the performance of the layer, its roughness and hardness, is not enough. In this paper, the relation between the gap width and layer performance is discussed in order to improve the layer performance. First, the results of experiments on single electrical discharge are shown. Then the results of this surface modification (EDC) is shown.
