Optimum Selection of Machining Parameters in Electrochemical Machining using Response Surface Methodology

Response Surface Methodology (RSM) was applied to the Electrochemical Machining (ECM) of AISI 1035 medium carbon steel specimens. Three independent parameters: voltages, feed rate and Inter Electrode Gap (IEG) were chosen as the process variables, whilst the Metal Removal Rate (MRR) and surface roughness of the finished specimens were the response variables. A first-order experiment was performed to determine the magnitudes of the relative changes to the process variables that would result in a better MRR and surface roughness. A second-order central composite design was used subsequently to locate the optimum conditions for achieving the best MRR and surface roughness. A maximum value of MRR of 266 mm(3)/min and a minimum value of surface roughness Ra of 1.5 mu m were predicted at an ECM applied voltage of 12 V, tool feed rate of 0.24 mm/min and IEG of 0.05 mm. Confirmatory tests showed that the actual performance at the optimum conditions were 251 mm(3)/min and 1.59 mu m, a deviation from the predicted performance of only 6 %.