The Optimization of the Electro-Discharge Machining Process using Response Surface Methodology and Genetic Algorithms

Abstract

Electric Discharge Machining (EDM) is a thermo-electric non-traditional machining process in which material removal takes place through the process of controlled spark generation between a pair of electrodes which are submerged in a dielectric medium. Due to the difficulty of EDM, it is very complicated to determine optimal cutting parameters for improving cutting performance. So, optimization of operating parameters is an important action in machining, particularly for unconventional electrical type machining procedures like EDM. A proper selection of machining parameters for the EDM process is heavily on the operator's technologies and experience because of their numerous and diverse range. Machining parameters provided by the machine tool builder cannot meet the operator's requirements. Since for an arbitrary desired machining time for a particular job, they do not provide the optimal conditions. To solve this task, multiple regression model and modified Genetic Algorithm model are developed as efficient approaches to determine the optimal machining parameters in electric discharge machine. In this paper, working current, working voltage, oil pressure, spark gap Pulse On Time and Pulse Off Time on Material Removal Rate (MRR) and Surface Finish (Ra) has been studied. Empirical models for MRR and Ra have been developed by conducting a designed experiment based on the Grey Relational Analysis. Genetic Algorithm (GA) based multi-objective optimization for maximization of MRR and minimization of Ra has been done by using the developed empirical models. Optimization results have been used for identifying the machining conditions. For verification of the empirical models and the optimization results, focused experiments have been conducted in the rough and finish machining regions.