Effect of shallow cryogenic treated brass wire electrode on workpiece surface roughness in wire-EDM

Abstract

In this paper, the effect of shallow cryogenic treated (–110°C) brass wire electrodes on workpiece (EN-31) surface roughness (SR) in wire electrical discharge machining (wire-EDM) is investigated. Five process parameters, namely type of wire, pulse width, time between two pulses, wire tension and servo reference mean voltage have been considered. The outcome of the investigation will identify the significant parameters and their effect on SR with shallow cryogenic treated and untreated wire electrode. The study indicated that all the selected parameters except wire tension and servo reference mean voltage have a significant effect on the means and S/N ratio (of analysis of variance) for SR. Taguchi experimental design has been applied to investigate the optimal parameters for minimisation of SR. The analysis of variance (ANOVA) analysis indicates that the shallow cryogenic treated wire reduces the SR. The results of confirmation experiments for SR showed that the setting of pulse width at low level (0.4 μs), time between two pulses at high level (16 μs) and selecting shallow cryogenic treated wire, produced optimal surface roughness (SR) from EN-31 material surface.