Effect of Higher Peak Current and Pulse Duration on EWR of Copper Electrode when Electrical Discharge Machining (EDM) of Inconel 718

In this work, the electrode wear rate (EWR) and electrode surface characteristic of copper electrode when EDM of Nickel Based Super Alloy, Inconel 718 at higher peak current and pulse duration were analyzed. Experiments were conducted using Inconel 718 as a work piece and copper as an electrode with a kerosene dielectric under different peak currents and pulse durations. Peak current, Ip within a range of 20A to 40A and pulse duration (or pulse on-time), ton within a range of 200μs to 400μs are selected as the main parameters. In this study, EWR were measured using digital weight balance (accuracy 0.01mg) and by using Scanning Electron Microscope (SEM), the surface texture of the electrode in order to evaluate the material deposited on the electrode surface. The results have shown that machining at a lowest peak current of 20A and highest pulse duration of 400μs yields the lowest electrode wear rate (EWR) of -0.01mm3/min. The pulse duration is significantly affecting the EWR. It also revealed that, the deposited of carbon and work piece material is occurred on the electrode surface for all machining conditions.