Electrochemical micromachining process is one among the successful micromachining technique, which uses the electrochemical energy and is recognized for machining difficult-to-cut materials. One such material is Nimonic 75 alloy, which is used to make gas turbine components. In this study, an effort has been made to machine micro-hole profiles in Nimonic 75 with a thickness of 500 μm using two different electrolytes. A combination of sodium bromide, hydrofluoric acid and ethylene glycol has been chosen as the first electrolyte, while the second is a combination of sodium chloride and sodium nitrate. Solid tungsten carbide of diameter 500 μm is used as the tool in each case. For layout of experiments, Taguchi orthogonal array was chosen with following input parameters namely voltage, micro-tool feed rate and duty cycle. Performance characteristics such as material removal rate, overcut and conicity have been assessed for each electrolyte. Experimental results have shown that the first electrolyte yields lower values of overcut (OC) and conicity, whereas the second electrolyte gives higher material removal rate (MRR). Further, the optimal combinations of process parameters have been found by implementing the TOPSIS procedure and the results were found to be in good agreement with the experimental outcomes.
Study and evaluation of process parameter on Nimonic 75 alloy by Electrochemical micromachining
