An experimental investigation on effect of the graphite powder mixed dielectric fluid on electro discharge machining of Ti-6Al-4V alloy

Ti-6Al-4V alloy creates difficulties in electric discharge machining (EDM) - one of the non-conventional machining methods - as well as conventional machining methods. It is observed that material removal rate of the titanium alloys are very low besides their high electrode wear ratio in EDM. The goal of this study is to improve the EDM performance characteristics (namely, material removal rate, electrode wear ratio, relative wear and surface roughness) with the addition of graphite powder into the dielectric fluid. The conducted experiments in this study have shown that 5 g/l concentration of graphite powder increased the material removal rate between 24.3% and 103.6%, reduced the surface roughness between 1.2% and 17.03%, decreased the relative wear between 0.7% and 25% and increased the electrode wear ratio between 8.2% and 55%. Three dimensional topographic views of the machined surfaces were created for both experimental conditions. The surface topographies have shown that the addition of the graphite powder, decreased Rz(DIN) values between 5% and %16.Key Words : Electrical discharge machining, Ti-6Al-4V, powder mixed dielectric, surface roughness, material removal rate, electrode wear ratio, surface topography