روشی برای افزایش سختی میکرو در ماشینکاری الکتریکی با افزودن پودر رسانایی به دی الکتریک

The present study deals with investigations on the effect of process variables on micro-hardness during electro-discharge machining (EDM) and powder mixed electro-discharge machining (PMEDM) of H-11 die steel. Taguchi’s L27 orthogonal array has been used to conduct the experiments using chromium powder mixed dielectric fluid with varying “powder concentration (Cp), peak current (Ip), pulse on time (Ton), duty cycle (DC) and gap voltage (Vg).” Analysis of variance (ANOVA) has been used to establish the optimal setting. Empirical model has been developed to predict micro-hardness. The optimum set of parameters for maximum micro-hardness was identified as Cp of 6 gm/l, Ip of 9Amp, Ton of 150μs, DC of 80% and Vg of 50 V. Confirmatory test reveals a relative error of 1.95% between predicted and experimental values of micro-hardness. Material migration from tool to the machined surface, conductive powder and dielectric fluid has been analysed using “Scanning Electron Microscope” (SEM) and “Energy Dispersive Spectroscopy” (EDS).