Comparative analysis of the rotary tool performances for Bio-dielectrics over conventional dielectric at optimum condition in EDM

Electro-discharge machining (EDM) is a widely used non-traditional machining process for shaping hard, electrically conductive materials with the help of a conductive tool and a dielectric fluid. Bio-dielectric fluids are increasingly adopted, in line with United Nations sustainability guidelines. Bio-dielectrics offer advantages such as higher flash points, superior biodegradability, lower toxicity, and reduced carbon emissions. However, their relatively higher density and viscosity can reduce pumping efficiency, flushing performance, and cooling capability during EDM operations. Rotational tool in EDM has been widely used to improve the machining characteristics. In the present work, EDM was carried out at optimum values of parameters and compared the performances of machining with rotation of tool over stationary tool using EDM oil, Jatropha biodiesel and Rice bran biodiesel as dielectrics. In this context, the experimental results revealed that the tool rotation has remarkably improved the MRR and average surface finish. Maximum MRR has been improved by Rice bran BD followed by Jatropha BD and minimum by EDM oil. In parallel, maximum SR has been improved for EDM oil followed by Rice bran BD, and minimum for Jatropha BD. At last, from the FESEM results it has been concluded that Micro-holes, Micro-cracks and RLT have been reduced significantly with tool rotation in EDM.