Effects of wire-Cut EDM process parameters on surface roughness of HSLA steel

Wire-cut EDM is used to produce complex-shaped and delicate parts; however, surface roughness (SR) is entirely dependent on optimal combination of input process parameters which is a difficult task. In this research, surface roughness model has been developed for high-strength low-alloy (HSLA) steel (30CrMnSiA, 38HRC). A series of experiments using factorial designs of experiments have been conducted to develop relationship between SR and WEDM process parameters namely, pulse-on time, pulse ratio, power (discharge current), wire speed and pulse (discharge gap). It has been found that pulse-on time has the highest impact on SR followed by wire speed, power and pulse. WEDMed surface was also examined by scanning electron microscope (SEM) to study the physical behavior of these process parameters. Results of ANOVA also indicated that interaction effects are important for surface roughness in addition to main effects. Accuracy of the proposed model has been confirmed through residual analysis and validation experiments.