Department of Mechanical Engineering, K.N. Toosi University of Technology, Tehran, P.O. Box 19395-1999, Iran
This research proposes a unied scheme to mathematically model and multiobjectively optimize the EDM parameters on tungsten carbide cobalt alloy (WC-6%Co), applying response surface methodology and a desirability function technique. Discharge current, pulse on-time, duty cycle and average discharge voltage have been chosen to be correlated with material removal rate, tool wear rate and surface roughness (Ra) as performance measures. The required experimental data were obtained in accordance with the face-centered central composite design. Signicant parameters in the form of main, twoway interaction and pure quadratic eects were carefully identied conducting a complete analysis of variance at 1%, 5% and 7% signicance levels, and the adequacy of all tted second order regression models was conrmed. Parametric analysis was undertaken through direct and reciprocity eect plots to fully reveal the dierent facets of ED-machinability characteristics. Finally, the optimization issue has been formulated as multi-objective from which the optimal parametric setting, yielding the most enviable conditions simultaneously, was then obtained in a compromised manner employing the notion of a desirability concept. The predicted optimal results were also interpreted and veried experimentally. The values of relative validation errors are all quite satisfactory (below 11%), which prove the ecacy and reliability of the suggested approach.