Optimization of Input Parameters Used for Machining Heat-Treated 0.2%-C Steel Under the EDM Method

The present work deals with the optimization of input parameters involved in ‘electric discharge machining (EDM)’ of AISI 1020 steel with 0.2% carbon content. A total of five such samples, each consisting of a unique physical characteristic, were selected in the work. The first sample was in the original or "as received" state, while the next two were hardened by quenching them into water and oil respectively. The normalizing heat treatment was followed for the fourth sample whereas the fifth was annealed. The hardness of the samples got significantly varied after heat treatment. Current, pulse-on-time, and pulse-off-time were the three distinct input characteristics taken into consideration as variables. The output parameters were determined by the surface finish of the cut and weight loss after machining. EDM tool of brass was chosen for investigation. Eight different sets of machining parameters were chosen to cut slots on every sample for the five plates. The ANOVA method was used to analyze the impact of inputs on the response and the experimental data were formulated using the Taguchi method. The purpose of this study is to find the effect of varying hardness, developed due to heat treatment, on the machining performance of the EDM. It was found that water and oil-quenched specimens, harder than other samples, could be machined at a relatively lower current. The difference noted in EDM parameters proves that the heat treatment process has successfully improved the material’s properties.