Electric discharge machining of Al–10%SiCP as-cast metal matrix composites

The use of unconventional machining techniques in shaping aluminium metal matrix composites (Al-MMC) has generated considerable interest as the manufacturing of complicated die contours in these hard materials to a high degree of accuracy and surface finish is difficult. Electrical discharge machining (EDM) is an important process for machining difficult-to-machine materials like metal matrix composites. Among the many unconventional processing techniques, EDM has proved itself to be one among the effective tool in shaping such difficult-to-machine materials. The objective of this work is to investigate the effect of current (C), Pulse ON-time (P) and flushing pressure (F) on metal removal rate (MRR), tool wear rate (TWR), taper (T), radial overcut (ROC), and surface roughness (SR) on machining as-cast Al-MMC with 10% SiCP reinforcement. ELEKTRAPULS spark erosion machine was used for the purpose and jet flushing of the dielectric fluid, kerosene, was employed. Brass tool of ∅ 2.7mm was chosen to drill the specimens. An L27 orthogonal array (OA), for the three machining parameters at three levels each, was opted to conduct the experiments. The experiments were performed in a random order with three successive trials. Analysis of variance (ANOVA) was performed and the optimal levels for maximizing the responses were established. Scanning electron microscope (SEM) analysis was done to study the surface characteristics.