Multi Objective Optimization of Process Parameters in WEDM during Machining of SS304

Abstract

Wire electrical discharge machining (WEDM) allowed success in the production of newer materials, especially for the aerospace and medical industries. Using WEDM technology, complicated cuts can be made through difficult-to-machine electrically conductive components. WEDM is valuable because of its fine surface finish and its high degree of accuracy. The process is so complex that using trial and error method it is very difficult to set the process parameters at the correct range. Hence there is a need to develop the method for finding the optimal process parameters or control variables, so that the desired surface finish and MRR can be attained. In general, the selection of machining parameters in any machining process significantly affects production rate, product quality and production cost of a finished component. WEDM is a complex process involved with more number of control variables or parameters that affect its performance. However, after conducting pilot experiments and the literature survey more influencing parameters are found out and five process variables, viz., pulse on time, pulse off time, wire tension, and water pressure are taken into consideration for the research. In the present work Response Surface Methodology (RSM) is used to develop the quantitative relationships between the input and the output responses for the experimental data collected as per the DOE. Also the effects of the input process parameters over the MRR and Ra were plotted and studied. Later it is formulated as a multi objective optimization problem and solved for pareto optimal set using NSGA algorithm.