A finite element model of EDM based on the Joule effect

A thermal-electrical model was developed for sparks generated by electrical discharge in a liquid media. A cylindrical shape has been used for the discharge channel created between the electrodes. The discharge channel being an electrical conductor will dissipate heat, which can be explained by the Joule heating effect. The amount of heat dissipated varies with the thermal-physical properties of the conductor; as a result, the maximum temperature reached is different. In the present model, the radii value of the conductor is a function of the current intensity and pulse duration. The thermal-physical values used in the model are the average of both the ambient and melting value. Copper and iron are the materials used for anode and cathode, respectively. The Finite Element Analysis (FEA) results were compared with the experimental values of the table of AGIE SIT used by other researchers [D.D. DiBitonto, P.T. Eubank, M.R. Patel, M.A. Barrufet, Theoretical models of the electrical discharge machining process-I: a simple cathode erosion model, Journal of Applied Physics, 66(9) (1989) 4095-4103; M.R. Patel, M.A. Barrufet, P.T. Eubank, D.D. DiBitonto, Theoretical models of the electrical discharge machining process-II: the anode erosion model, Journal of Applied Physics, 66(9) (1989) 4104-4111; P.T. Eubank, M.R. Patel, M.A. Barrufet, B. Bozkurt, Theoretical models of the electrical discharge machining process-III: the variable mass, cylindrical plasma model, Journal of Applied Physics, 73(11) (1993) 7900-7909]. In order to show the universality of the model it was obtained results for all current intensity values of the table. The Toot Wear Ratio (TWR) and Material Removal Rate (MRR) as well as surface roughness results agree reasonably well with the researcher's values found for that table and itself. (C) 2005 Elsevier Ltd. All rights reserved.