Surface Modification by EDM with Carbon Powder Mixed Fluid using Titanium Electrode

Abstract

Recently, it was reported that a hard TiC layer could be made on the machined surface by EDM using a titanium electrode in kerosene and this technique was applicable to cutting tool such as throwaway tip or endmill. However, the layer is relatively thin and the surface roughness is not so small. Then, it is difficult to apply this method to a metal mold which needs glossy surface. In this study, a new method to form TiC layer by EDM for smaller surface roughness and thick layer is proposed, and the effects of machining conditions on characteristics of the layer are experimentally investigated. Furthermore, the wear resistance of EDMed surface was evaluated.Experimental analysis made it clear that a thick and smooth TiC layer could be generated on the machined surface by EDM using a titanium electrode in carbon powder mixed fluid. It was also pointed out that the hardness of modified surface became higher with increases of discharge duration or carbon powder concentration in the kerosene type machining fluid, and that the wear resistance of the layer was much larger than that of base material.