Parameter Optimization of the CNC Wire-Cut EDM Process for Machining Aluminium 6063-B4C Metal Matrix Composites

In the competitive manufacturing environment, conventional monolithic materials cannot compete with composite materials in the ever growing market because of their inherent limitations. Consequently, composite materials are preferred globally in major industries. CNC wire-cut electrical discharge machining is one of the non-traditional machining (NTM) processes, which are used to cut ferrous and non-ferrous metals with properties ranging from low hardness to high hardness and especially to cut high hardness materials and complicated profiles and shapes of all engineering and aerodynamic products. The process parameter setting is critical in the wire-cut electric discharge machining (WEDM) as it has a direct impact on performance characteristics. This paper addresses the preparation of aluminium metal matrix composites (AMMCs) and the optimization of the WEDM process parameters for machining AMMCs to improve the key performance characteristics, namely the metal removal rate (MRR), the surface roughness (SR), and the kerf width (KW). The optimization of the WEDM process parameters is multi-objective in nature. The prime objective of this study was to obtain optimal WEDM process parameters for machining AMMCs with the maximum MRR and the minimum SR and KW. The grey-based Taguchi method was applied to choose an optimal parameter combination to achieve the above said performance characteristics. AMMCs with the base metal Al6063 and the reinforcement of boron carbide (B4C) in three different percentages (3%, 6% and 9%) were obtained by using the stir casting method. WEDM experiments were conducted and the optimal process parameters were found to be as follows: servo voltage (SV)-26V, pulse on time (Ton)-122µs, pulse off time (Toff)-52 µs, B4C-6%, wire feed-3 m/min, and wire tension-49.05N. The key findings from this study reveal that the MRR was increased from 35.759 mm3/min to 42.229 mm3/min, the SR decreased from 4.500µm to 4.382µm and the KW decreased from 371 micron to 364 micron