Parametric Optimization of Micro-EDM Process during Micro-hole Machining on Ti-6Al-4V using WASPAS Method

Abstract

Micromachining of Ti-6Al-4V is extremely difficult using conventional machining processes, especially during machining of micro-cavities and micro- through holes as it exhibits poor machinability. Amongst various non-conventional machining processes, micro-electro discharge machining (micro-EDM) has been recognized to be most suitable machining method for micromachining of Ti-6Al-4V. However, micro-EDM is an extremely complicated micromachining process, influenced by several process parameters. In present research investigation, an attempt has been made to select the optimal combination of micro-EDM process parameters such as pulse on time (Ton), peak current (Ip), flushing pressure (Fp) and type of dielectric, which greatly influence the micro-EDM process during machining of Ti- 6Al-4V using WASPAS (Weighted Aggregated Sum Product ASsessment) method. In a series of planned experimental runs, micro-through hole machining has been carried out during experimental investigation and a model for multi-criteria decision making (MCDM) has been successfully developed in order to identify the optimum process parameters in micro-EDM process, which influence several machining criterion such as material removal rate (MRR), tool wear rate (TWR), overcut (OC) and taper. WASPAS method has been applied to obtain the optimal process parameters from the sets of various combinations of process parameters in order to achieve maximum MRR and minimum TWR, OC and taper during machining of Ti-6Al-4V. The obtained optimal process parametric combination has been experimentally validated and a significant improvement of 30.87% is observed.