Optimization of Pulsed Current Electrochemical Micro Machining of MONEL 400 Alloy in NaNO3 Electrolyte

Components having micro-holes find wide application in fields like aircraft, automobile, healthcare, power circuit boards and ink jet printing nozzles. Monel 400 alloy which is a mixture of nickel and copper is the prime material used for such components. Experiments were conducted by supplying pulsed atmospheric air to the electrolyte with a view to effectively remove the residual machined material. Micro holes were machined using (ECMM) and a single electrolyte. The machining factors namely the percentage of the electrolyte, applied voltage, duty cycle and frequency had been taken as dominant factors. Their optimal combination was arrived using standard optimization techniques, such as, Technique of Order Preference Similarity to the Ideal Solution (TOPSIS), VlseKriterijumskaOptimizacijaKompromisnoResenje (VIKOR) and Complex Proportional Assessment (COPRAS), using material removal rate (MRR) and overcut as response metrics. All the three methods indicated the same optimal parameter combinations. All three methods exposes the same optimal parameter combinations that 28 g/l, 13 V, 75 % and 90 Hz for the first position. Also, the ANOVA results revealed that electrolyte concentration and machining voltage contributes around 62 % and 41 % respectively on the ECMM performance. Further, the quality of micro-hole on work material with the use of pulsed air supply to electrolyte was studied by obtaining scanning electron microscopy (SEM) images and checking the finish of the hole circumference.