Study on the influence of micro-EDM process parameters during machining of Ti–6Al–4V superalloy

Ti–6Al–4V superalloy is an important engineering material having a wide range of applications in diverse fields of engineering due to its good machinability features and excellent physical and mechanical properties. These versatile properties of titanium alloy have caught the interest of researchers and industries personnel across the globe. Further, micromachining of Ti–6Al–4V has become the topic of interest for industrial production and engineering research in the precision manufacturing world due to its wide range of applications in various fields of engineering. However, the machining of Ti–6Al–4V requires in-depth knowledge of machining process as this involves various process variables which influence the machining criteria. Micro-electro discharge machining (micro-EDM) is one of the most successful micromachining processes, and the machined component is free from mechanical stresses as there involve no mechanical forces in the process because there is no direct contact between the tool and workpiece. Also, the specific energy requirement is very low in this process, and the accuracy is very good, i.e., in the order of 0.1 μm Rmax. Thus, in this research paper, an attempt has been made to study the influence of various process parameters on material removal rate (MRR), tool wear rate (TWR), overcut (OC), and taper of micro-EDM during machining of Ti–6Al–4V. To perform the experimentation, central composite design (CCD) has been used to design the experiment and response surface methodology (RSM) is utilized to map the relationship between the input process parameters with the resulting process response. It has been observed that RSM models have predicted the process criteria, namely, MRR, TWR, OC, and taper, satisfactorily and can be utilized to predict the response parameters within the range of the parameter selected in the present research investigation. Through multi-objective optimization, the optimal parametric setting for the micro-EDM process parameters during machining of Ti–6Al–4V has been obtained at pulse on time (Ton) of 1 μs, peak current (Ip) of 2.5 A, gap voltage (Vg) of 50 V, and flushing pressure (Fp) of 0.20 kg cm−2. The experimental values of MRR, TWR, OC, and taper at this optimal parametric setting have been obtained as 0.0777 mg/min, 0.0088 mg/min, 0.0765 mm, and 0.0013, respectively.