Effect and Optimization of EDM Process Parameters on Surface Roughness for En41 Steel

Abstract

Unconventional machining is gaining more and more importance in today’s manufacturing methods because of its applications over conventional machining. Machining of Complex shapes, high dimensional accuracy and good surface finish can be achieved by unconventional machining processes. Surface Finish is an important quality characteristic for machined parts. In the present work, an investigation has been done to find the effect of EDM process parameters on Surface Roughness in machining of medium carbon steel EN41. For the experimentation, Pulse on time (PON) and Pulse off time (POFF), wire tension (WT) and wire speed or wire feed (WF) are selected as input parameters and Surface Roughness (Ra) is considered as a response. The experiments were performed on CNC- EDM machine as per Taguchi’s standard L27 (3level*4factors) Orthogonal array. Taguchi’s single objective optimization method is used to find the optimal combination of process parameters affecting the Surface Roughness. From the results, the optimal combination of process parameters is found at PON (level 2, value 123 μs), POFF (level 2, value 58 μs), WT (level 1, value 2 Kg-f) and WF (level 1, value 4 m/min). From Analysis of variance (ANOVA) results, Wire Feed rate has high influence (F = 61.94, P = 0.000) in effecting the Surface Roughness and Pulse ON time has the least influence (F = 1.99, P = 0.166) among all the process parameters. A Mathematical model was developed for Surface Roughness by using MINITAB-16 software. The model is a good fit and it can be used for the prediction of Surface Roughness as it has low variance (S = 0.608144) and high Coefficient of determination value (R-Sq = 82.4%). The model values are compared with experimental values and they found very close to each other.