Publication

Abstract : The influence of process parameters on surface roughness (SR), material removal rate (MRR) and tool wear rate (TWR) in electric discharge machining (EDM) of aluminium-fly ash-graphite hybrid metal matrix composites was investigated. The design of experiments approach using Taguchi method was employed to optimise the parameters like peak current, flushing pressure and pulse on time (T on) in EDM of hybrid composites for minimum SR and TWR, and maximum MRR. An Electronica-Small die sinking electric discharge machine was used to drill holes in the hybrid composite workpiece. Experiments were conducted based on the Taguchi parameter design by varying the peak current, flushing pressure of dielectric fluid and T on). Signal-to-noise ratio and analysis of variance were used to investigate the influence of parameters on the SR, MRR and TWR. It was determined that peak current was the most significant parameter influencing the responses, followed by T on) and flushing pressure. There was an increase in the SR of hybrid composites with increases in peak current and T on) due to the generation of much larger and deeper craters on the drilled surface. SR also increases with an increase in flushing pressure. It was determined that the MRR increases almost linearly with increases of peak current, flushing pressure and T on). There was an increase in TWR with increases in peak current and flushing pressure. However, when T on) was increased, there was a marginal decrease in the TWR due to formation of carbon deposits on the electrode. Multiple linear regression models were developed to predict the SR, MRR and TWR. © EuroJournals Publishing, Inc. 2011.