Experimental Investigation to Achieve Minimum Surface Roughness in Wire EDM Process

Abstract

This paper presents the behaviors and evaluation of Wire Electrical Discharge Machining (Wire EDM) manufacturing process. Wire EDM is also known as Wire-cut EDM, which uses a dielectric fluid submerged thin metallic wire to cut the conductive work piece material. Taguchi orthogonal array was used for planning the experiments to optimize the control variables for better surface roughness while machining AISI 420 modified metallic material. Pulse-on/off Time, Wire Feed, Spark Voltage and Peak Current were selected as the control variables. AISI 420 metal, also called as Stavax®ESR has a higher metal strength and is used for all types of moulds and moulding tools in the industry. The experiments were carried out by changing the aforesaid control variable parameters and TR200 handheld roughness tester was used to measure the surface roughness of metal cuts. Three surface roughness measurements were taken for each machined section and averaged. Plotting method and Analysis of Variance (ANOVA) were used for the analysis and interpretation of the results. Error variances were estimated by using Pooling-up strategy. The influences of each control parameter on surface roughness were estimated. Then, the results were used to develop a mathematical model. The developed mathematical model can be used to minimize surface roughness. Control variable parameter settings for the optimized surface roughness can be obtained by using the mathematical model.