Investigating the role of biodegradable dielectric fluids in micro-EDM precision for Inconel 718 alloy

Abstract

Electric discharge machining (EDM) finds diverse applications in industries such as aerospace, medical equipment manufacturing, dies and molds production, nuclear technology, and the automobile industry. Inconel 718 is a nickel-based superalloy with unique features, such as high strength and stability in hostile environments. The inherent problem of radial overcut in conventional EDM restricts its use in the machining of nickel-based alloys. Furthermore, the use of traditional dielectric oil in EDM emits harmful gases and fumes that endanger the environment and the operator’s health. As a result, this study has examined the possibility of four distinct biodegradable dielectric oils handling the geometrical overcut, which has not yet been fully assessed. Using a full factorial design, the effectiveness of biodegradable oils (sunflower, polanga, canola and coconut) has assessed with three different machining tool materials (copper, brass and graphite) in EDM of Inconel 718 superalloy. Results are examined using mathematical analysis and scanning electron microscopy (SEM). The experimental findings showed that the overcut measurement value is minimum during canola as a dielectric fluid. The combination of sunflower oil and a copper tool was the second most effective method for reducing overcut. Compared to normal kerosene dielectric oil, canola biodegradable dielectric has a 71% reduction in overcut.