Optimization of process parameters during WEDM of EN-42 spring steel

Abstract

The present work aimed to carry out the machining of EN-42 spring steel in wire electrical discharge machining with zinc-coated brass wire using distilled water as a dielectric medium. The effect of WS 2 powder added in a dielectric medium, on the metal removal rate and surface roughness has been evaluated. With the use of WS 2 , the conductivity of the dielectric is found to be constantly equal to 10 S/m, which is a very promising feature. WS 2 enhances dielectric life, metal removal rate, and surface roughness significantly. The effect of cryogenically treated wire on the metal removal rate and surface roughness during machining has been carried out. Taguchi method and genetic algorithm were used to optimize machining performance measures. Both methods provide optimum parameters and target value. The results of the Taguchi method show more error as compared to the genetic algorithm. The on time can be predicted as the most significant parameter according to the Taguchi method. From the results, it is observed that higher on time shows better metal removal rate and lower on time shows a better surface finish. Keywords Cryogenic treatment • Metal removal rate • Root mean square surface roughness • Taguchi • S-method • Genetic algorithm • EN-42 spring steel Abbreviations EDM Electrical discharge machining TWR Tool wear rate ASTM American society for testing and materials S/N Signal to noise ratio WEDM Wire electrical discharge machining Notations T on On time, µS T off Off time, µS F wf Wired feed, M/min F sf Servo feed, M/min MRR Material removal rate, m 3 /min