Performance parameters optimization (multi-characteristics) of powder mixed electric discharge machining (PMEDM) through Taguchi’s method and utility concept

Abstract

Electrical discharge machining (EDM) is widely used in the production of dies. This paper describes an investigation into the optimization of the EDM process when silicon powder is suspended into the dielectric fluid of EDM. Taguchi’s method with multiple performance characteristics has been adopted to obtain an overall utility value that represents the overall performance of powder mixed EDM (PMEDM). The four input process parameters, viz., concentration of silicon powder added into the dielectric fluid, peak current, pulse duration and duty cycle, are optimized with consideration of multiple performance characteristics including machining rate (MR), surface roughness (SR) and tool wear rate (TWR). A modified powder mixed dielectric circulation system has been developed. Experiments have been performed on the newly designed experimental set-up developed in the laboratory. The obtained experimental results indicate that the peak current and concentration of the silicon powder suspended into dielectric fluid are most significant parameters. Moreover, the performance of PMEDM has improved over EDM. The predicted optimal values for MR, SR and TWR obtained for PMEDM are 1.22 mm³/min, 0.51 μm and 0.005 mm³/min respectively. The results are further verified by conducting confirmation experiments.