Multi-objective optimisation of electrochemical micro drilling of titanium alloy

Pulsed electrochemical micro machining is a specific technique developed for high accuracy in hard to machine conductive materials. This paper aims to determine the parametric combination that achieves the optimal geometric and working characteristics of the drilled holes, namely circularity, conicity, overcut and material removal rate (MRR) in drilling titanium. Taguchi orthogonal array was chosen for the layout of experiments and the grey relational technique was chosen as the optimisation tool. The input parameters considered are electrical and the response parameters are circularity, conicity, overcut and MRR of the drilled holes. Scanning electron microscope images were observed to find differences in wall thickness arising due to variations in current, voltage and frequency levels used for the experiment. The grey relational analysis revealed that combination of higher levels of current and voltage, central level of frequency produced the hole satisfying the output parameters, MRR and Overcut.