EXPERIMENTAL STUDY OF PROCESS PARAMETERS ON MACHINING PERFORMANCE IN ELECTRO-DISCHARGE MACHINING OF 6061Al/TiC/Gr COMPOSITES

This study employs Taguchi orthogonal design (L9) to optimize the machining parameters of electro-discharge machining (EDM). The aluminum matrix composite (AMC) with 16wt.% titanium carbide (TiC) and 4wt.% graphite (Gr) specimen was prepared by stir casting process. This study involves three control parameters with three levels, namely pulse current, voltage and fluid pressure to predict the process response, such as material removal rate (MRR) and surface roughness (SR) of the worn surface. Maximum MRR of 0.1661g/min was attained for 10A, 500V and 15kgf/cm2 fluid pressure with corresponding roughness of 11.43μm and the minimum value of 7.51μm was observed for 10A, 100V and fluid pressure of 5kgf/cm2. A regression model was developed and the effect of control parameters on process responses were determined by analysis of variance (ANOVA). According to ANOVA outcome, the machining parameters which control the process response MRR were determined as voltage (47.94%), pulse current (33.19%) and fluid pressure (17.58%). Similarly, the SR was affected by machining parameters voltage (55.17%), pulse current (22.41%) and flushing pressure (21.47%). The optimum machining parameters were predicted and confirmed by conducting experiments with reasonable error of 2.49% and 2.02% for MRR and SR, respectively. Surface characteristics of the machined AMC was analyzed by scanning electron microscope (SEM) to observe the defects like craters, voids, glued debris and recast layers.