Mathematical modelling with experimental correlation for multiple craters dimension, material removal rate and surface roughness in electrical discharge machining

Electric discharge machining (EDM) is a non-conventional machining process, which has gained popularity in the manufacturing industries. In this study, analytical models have been presented to calculate the surface roughness and material removal rate based on multiple-craters geometry. To begin, the geometry of a single crater is calculated that was converted into multiple craters. Following on, the material removal rate (MRR) and average surface roughness were calculated. The model was able to estimate crater depth, width, average roughness and MRR with a deviation of 3–5%, 5–7%, 4–7% and 5–8%, respectively. It was found that as the pulse energy is 20 times greater as compared to the lower capacitance thereof, a deeper crater is realized. The pulse energy becomes quadruple as open voltage upsurges from 60 to 120 V, but the capacitance remains unchanged. The crater depth, on the other hand, does not increase as the open voltage is increased. The crater’s width expands linearly as the capacitance and open voltage increase. This is attributed to the expansion of plasma radius at higher magnitude of pulse energy, causing the crater to widen.