Parametric optimization of wire electrical discharge machining on aluminium based composites through grey relational analysis

Wire Electrical Discharge Machining (WEDM) is an advanced machining process, which is suitable for making complex shapes in conducting materials including metal matrix composites (MMCs). In the present work, an analysis has been made to optimize the process parameters such as peak current, pulse on time, wire feed rate and wt.% of Boron Carbide (B4C) that affect the output responses, namely, kerf width (K) and surface roughness (SR), through the Grey Relational Analysis (GRA). Aluminium (6351) alloy reinforced with 5 wt.% Silicon Carbide (SiC) and 0, 5, 10 wt.% of B4C prepared through the stir casting process was used for the evaluation. The experimental results show that the optimal combination of process parameters were peak current of 12 A, pulse on time of 100 μs, wire feed rate of 6 m/min and B4C content of 5 wt.%. The influence of the pulse on time is found to be more in affecting the combined objective with a contribution of 96.19%. The crater formation on the machined surface of the composite at optimum condition was also examined through the Scanning Electron Microscope (SEM).