Feasibility of used cooking oil-based biodiesel (UCOB) as a dielectric for electrical discharge machining

This study is centered on the practicality of used cooking oil-based biodiesel (UCOB) as the dielectric for electrical discharge machining (EDM). To establish the usefulness of used cooking oil-based biodiesel as a dielectric for EDM, the essential properties of UCOB were determined and compared with ST EDM oil. Used cooking oil is an important source that can be employed for biodiesel production. Biodiesel was extracted by the process of transesterification. EDM performance was evaluated by applying a “one factor at a time” approach while machining Inconel-625 using EDM oil and bio-dielectric fluids. For both dielectric fluids, the material removal rate was observed to increase with discharge current. The lowest value of TWR was observed at 50 µs while the highest value was observed at 1000 µs. Thus, the performance trend for both fluids was similar. However, the performance of UCOB was slightly better than that of EDM oil. This variation is due to the difference in chemical composition of both dielectric fluids. The highest material removal rate 20.333 mm3/min was observed for UCOB operation at a discharge current of 12.48 A and the lowest material removal rate (0.123 mm3/min) was obtained with a discharge current of 1.56 A for EDM oil. It has been established that UCOB can be suitably utilized as dielectric fluid to increase the sustainability of the EDM process.