Investigation of surface roughness in wire electrical discharge machining of stainless steel

Abstract

In obtaining the best quality of engineering components, the quality of machined parts surface plays an important role. It is a fact that it improves fatigue strength, wear resistance, and corrosion of workpiece. Optimal machining parameters can only be determined by significant parameters that are affecting the properties of the machining performance. The aim of this study is to investigate effects of wire electrical discharge machining (WEDM) parameters towards the surface roughness and kerf width of stainless steel. The parameters selected are voltage open (Vo), off time (OFF), wire speed (WS), wire tension (WT) and voltage gap (VG). This research uses stainless steel 304 as a workpiece, 0.2 mm brass wire as a tool, and for dielectric fluid distilled water is used. Taguch is L16 orthogonal array has been used for experimental design and the optimum machining parameter was determined through signal-to-noise ratio analysis. Surface roughness and kerf width was determined by using Mitutoyo Surftest SV-514 and Jeol JSM-5600. The analysis of variance show that the off time had major influenced on the surface roughness and voltage gap on kerfs. The optimum machining parameter for the kerf and surface roughness was obtained at 12.65 V voltage open (Level 1), 4s off time (level 4), 12 m/min wire speed (level 4), 6 N wire tension (level 1), 51.21 voltage gap (level 3). The average of kerf width and surface roughness from the three experiments was 0.273 mm and 2.23 m respectively and from that, the error margin for kerf width was 8.79% and surface roughness was 8.07%.