Feasibility assessment of some alternative dielectric mediums for sustainable electrical discharge machining: a review work

Low removal rate, high power consumption, and dependency on conventional fuels (kerosene as a dielectric) are some premier issues that keep the sustainability index of EDM low, though it has huge acceptability and popularity mostly in aviation sectors and biomedical instrumentation to machine some extensively hard ferrous and nonferrous metal/metal alloys. Besides these, the thermal agitation inside the fusion/machining zone partially burns the dielectrics and tool-workpiece-metal, which evolve some oxides/monoxides. These evolved gases promote an unhygienic breathing atmosphere, which is very much harmful to the operator's health. Sometimes because of inadequate flushing pressure and velocity, carbon particles deposited inside the crater makes the spark unstable and releases carbon monoxide when the temperature exceeds its melting point. According to ISO 14000, every manufacturing process must be comprised of the sustainability criteria, which maintains a compromised balance between the economic, environmental, and social aspects, including the issue of the operator's health. But in real practices, it is very tough to maintain a stoichiometric balance between all these constraints. The article intensely focuses on the issue of emergence of gases during machining and tries to promote the utility of some alternative vegetable oil-based dielectrics, which are experimentally justified as a potent alternative of conventional kerosene. Apart from these, it includes some comparative talks on dielectric nature and their impacts on the responses and surface properties. Finally, this article highlights some compromise solutions which are probably capable of mitigating the hurdles to some extent, so that the sustainable machining can be encouraged in real sense.