Electrical Discharge Machining (EDM) is one of the popular processes for producing electrically hard to machine conductive parts. In this technique, the tool has no mechanical contact with the workpiece therefore, the hardness of workpiece has no effect on the machining pace. Hence, this technique could be used for machining such materials such as hot worked steels and super alloys. Inconel 718 super alloy is a nickel based alloy that is frequently used in various applications, especially in aerospace, oil and gas industries and power stations. In EDM, like other machining processes, the machining cost and the surface quality of final product are affected by the proper selection of parameters levels. Therefore, the main objectives of this research are, to assess the effects of process parameters and to determine their optimal machining levels of Inconel 718 super alloy. Gap voltage, current, time of machining and duty factor are tuning parameters considered to be studied as process input parameters. Furthermore, two important process output characteristic have been evaluated in this research are material removal rate and surface roughness. Determination of a combination of process parameters to minimize surface roughness and maximize material removal rate is the objective of this study. In order to gather required experimental data, D-optimal based design of experiments (DOE) technique has been used. Then, statistical analyses and validation experiments have been carried out to select the best and the most fitted regression models. In the last section of this research, simulated annealing (SA) algorithm has been employed for optimization of performance characteristics of EDM process. A set of verification tests is also performed to confirm the accuracy of the proposed optimization procedure in determining the optimal levels of machining parameters. The results indicate that the proposed modeling technique and SA algorithm are quite efficient in modeling and optimization of EDM process parameters.

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