Optimization of EDM Drilling Parameters for Aluminum 2024 Alloy Using Response Surface Methodology and Genetic Algorithm

Abstract

AA 2024 alloy is widely used as a structural material in aerospace applications. Its excellent strength to weight ratio makes it suitable for the subsequent application. The aerospace application required close tolerances and accuracy in the machined parts. Henceforth non-conventional machining processes are widely used for different machining operations such as drilling through holes. In the present study, Electrical Discharge Machining (EDM) process is used to drill through holes in 5mm thick AA 2024 alloy material. With the aim of reducing the difference between finished diameter of drilled hole and intended diameter, computational technologies were adopted for optimization. Mathematical models were developed using Response Surface methodology (RSM), and subsequently Genetic Algorithm (GA) was used to reach a set of input parameters in order to give minimum difference in diameter. Three input parameters such as current (I), Pulse on time (Ton) and Pulse off time (Toff) were selected. The ANOVA results indicated that developed models were adequate and robust. The GA based approach in conjugation with RSM was able to locate a single set of parameters which gave minimum difference in diameter. Confirmation test was again carried out and the difference between predicted and measured value was negligible.