Masoud Azadi Moghaddam - Student, Ferdowsi /Department of mechanical engineering;
Farhad Kolaham - Associate Prof, Ferdowsi / Department of mechanical engineering;
Morteza Andalib - Student, Ferdowsi / Department of mechanical engineering

In this paper Taguchi method has been employed to optimize Electrical Discharge Machining (EDM)process for 40CrMnMoS86 hot worked steel parts. The experimental data are gathered based on TaguchiL(36) design matrix. The tests are conducted under varying peak current (I), voltage (V), pulse on time(T(on)), pulse off time (T(off)) and duty factor (η). The effects of these input parameters are then determinedon three important process output responses, namely; Surface Roughness (SR), Tool Wear Rate (TWR) andMaterial Removal Rate (MRR). Using these data and signal-to-noise (S/N) ratio analysis, the processparameters can be set to achieve desired surface roughness, tool wear and material removal rates.Next, analysis of variance (ANOVA) and F–test have been used to evaluate the relative significance ofprocess variables affecting process outputs. A set of verification tests is also performed to verify theaccuracy of optimization procedure in determining the optimal levels of machining parameters. Theresults indicate that Taguchi technique is quite efficient in determining optimal process parameters.

Taguchi technique, Electrical DischargeMachining, Optimization, Analysis of variance,signal to noise