Generation of Stepped Profiles on Ti6Al4V by Electrochemical Milling

Generation of accurate complex-shaped products on various high-strength temperature-resistant (HSTR) alloys such as titanium and nickel alloys is a key feature for many kinds of machine parts widely used in diverse industries starting from biomedical to defence industries. Being free of tool wear, thermal stresses and residual stresses, electrochemical machining has great potential of machining those HSTR metal structures. The process of EC milling is similar to conventional ECM, where the material is removed by a simple geometric tool following a predefined path in a layer-by-layer fashion. EC milling avoids complex electrode design which is often a burden in sinking ECM. In this paper, attempts have been made to investigate the influence of different process parameters on various performance characteristics of EC milling of Ti6Al4V by generating stepped profiles, and then, optimization of process parameters have been done using Taguchi and grey relation analysis (GRA). Experiments were conducted based on Taguchi’s L27 orthogonal array with five important process parameters, i.e. electrolyte concentration, milling layer depth, feed rate, frequency and duty ratio. From analysis of variance, it was observed that electrolyte concentration and milling layer depth are the significant process parameters that mostly affect the responses. The experimental results show that for successful machining of Ti6Al4V by EC milling process, the optimal parametric combinations are 0.5 M electrolyte concentration, 0.15 mm milling layer depth, 0.04 mm/s feed rate, 5 kHz frequency and 50% duty ratio; and milling layer depth has a major influence on all the responses of EC milling of Ti6Al4V.