Assistant Professor, Department of Automobile Engineering, Nehru Institute of Technology, Coimbatore
Wire Electrical discharge machining is a popular advanced machining method of cutting, shaping materials that conducts electricity. Since it involves thermo-electrical mechanism of material removal and the number of controlling process parameters are many, it is recognized as a stochastic process. WEDM is environmentally safe, user friendly and easy to automate. O2 steel, a cold worked, difficult to machine material due to its toughness, wear resistance and high strength at elevated temperatures is used in making mechanical press-tool, drawing dies and punches. In this work the machining performance of O2 steel is improved with multi-response criteria based on the desirability approach. Experimental tests were carried out through a L16 orthogonal array design, at four levels. The influence of input factors, spark duration, off time, wire speed and gap voltage were analyzed on the performances of surface roughness and material removal rate. The optimum cutting conditions are obtained by desirability function approach. Analysis of variance is applied to sort the effect from pooled data. A regression model was developed for surface roughness and material removal rate. Confirmation experiment was carried out for the recommended optimal machining parameters. Good improvements were obtained.