Experimental and Theoretical Analysis of Surface Roughness in Electrodischage Machining (EDM) Performance

Abstract

Non-traditional machining techniques are extensively utilized for manufacturing parts with intricate shapes or composed of materials that are difficult to machine using conventional methods. Among these techniques, Electrical Discharge Machining (EDM) stands out due to its ability to overcome the limitations faced by traditional machining approaches. EDM removes material through controlled electrical discharges occurring between the electrode and the work piece. This research investigates the influence of EDM process parameters on machining high-speed steel AISI M2, employing both copper and graphite electrodes. The study emphasizes the effect of various machining parameters on surface roughness (Ra). The key factors considered in the experiments include discharge current, pulse-on time, and pulse-off time. Experimental outcomes reveal that the minimum surface roughness was obtained with copper and graphite electrodes at a current of 10 A, pulse-on time of 100 µs, and pulse-off time of 25 µs, producing Ra values of 2.18 µm and 1.67 µm, respectively. In contrast, the maximum surface roughness occurred at a current of 42 A, pulse-on time of 200 µs, and pulse-off time of 4 µs, yielding Ra values of 6.37 µm for copper and 5.98 µm for graphite electrodes. The results further indicate that graphite electrodes consistently achieve smoother surfaces than copper electrodes under identical machining conditions.