Optimization of the parameters for the surfactant-added edm of a Ti-6Al-4V alloy using the Gra-Taguchi method

Abstract

In this research, the Taguchi technique was applied to determine the optimum process parameters for the electrical discharge machining (EDM) of a titanium alloy with an added surfactant. The surfactant added to the dielectric fluid played an important role in the discharge gap, increasing the conductivity and suspending debris particles in the dielectric fluid, reducing abnormal discharge conditions of the machine and improving the overall machining efficiency. The performance characteristics were the material-removal rate (MRR) and the surface roughness (SR), which were experimentally explored for various input parameters such as the discharge current, the pulse-on time, the pulse-offtime and the surfactant concentration in the dielectric fluid. The optimum setting of the parameters was verified through planned and conducted experiments and analysed using the Taguchi technique. Further, a multi-response optimisation was carried out, maximising the MRR and minimising the SR, using the Grey relational analysis (GRA). It was observed that the pulse-on time, the discharge current, the pulse-offtime and the surfactant concentration contribute significantly to the multi-response optimisation. Conformation test results showed an improvement in the MRR by 20.69 % and in the SR by 11.09 %. A scanning-electron-microscope (SEM) analysis was conducted to study the recast layer that evolved during the electrical discharge machining process and the topography of surfaces was also observed.