PMEDM process parameter optimization for machining superalloy MONEL 400

Abstract

MONEL 400, widely used in industries such as high-temperature applications, chemical processing, automotive, and marine sectors, presents significant machining challenges due to its high strength and tendency for work-hardening. This research explores powder-mixed electrical discharge machining (PMEDM), a modern technique incorporating conductive metal powders, specifically graphite and silicon, combined with dielectric fluid to improve machining performance. The study investigates into how to machine MONEL 400 with copper as the cathode, focusing on important process parameters such as powder concentration, peak-current, and pulse on duration. This study also compared impact of PMEDM to conventional EDM, and results demonstrated improvements in material removal rate, tool wear rate, and surface roughness. Graphite powder significantly reduced tool wear, while silicon powder significantly enhanced surface finish. Using Buckingham’s theorem and regression analysis, this study presented semi-empirical models for the rate of material removal and looks at how the powder additives’ dielectric properties have changed to improve performance. The research aims to improve sustainable machining practices while providing environmental benefits.