Assessment of operational feasibility of waste vegetable oil based bio-dielectric fluid for sustainable electric discharge machining (EDM)

Abstract

Since the first application of electric sparks for the material removal was demonstrated, the electric discharge machining (EDM) process has gone through considerable changes in terms of technology and application. The process has surpassed the technological barriers by overcoming its then thought limitations like processing speed, material conductivity, dimensional and geometrical accuracies, and surface finish. However, environmental impact due to release of toxic emission products, operator health concerns due to release of toxic fumes, vapours and aerosols during the process, poor operational safety due to fire hazards and electromagnetic radiation, and toxic and non-biodegradable dielectric waste generated are some of the concerns still prevailing in EDM process. Authors, in this paper, have assessed the operational feasibility of waste vegetable oil (WVO) as possible alternative dielectric fluid and compared the response patterns of WVO with hydrocarbon oil, kerosene. Experiments were performed using spark current, gap voltage, pulse on time (pulse duration) and pulse off time (pulse interval) as control parameters to study the response behaviour for material removal rate (MRR), electrode wear rate (EWR) and tool wear ratio (TWR). The results obtained reveal that WVO-based bio-dielectric fluid can be used as an alternate to hydrocarbon-, water- and synthetic-based dielectric fluids for EDM. Besides the successful trials for operational feasibility assessment, application of bio-fluids offers a cleaner, greener and safer solution for dielectric to improve sustainability of EDM process by improving environmental friendliness, operational safety and personnel health issues of the process. Based on the experimental results and observations, the authors have suggested further scope of works to improve sustainability of the EDM process.