Assessing the performance of air, argon, and oxygen as dielectric mediums during dry-micro-EDM of Ti6Al4V alloy: A comparative study

Abstract

ABSTRACT Due to sheer environmental risks associated with hydrocarbon-based dielectric media, their use is discouraged not only in manufacturing processes but also throughout all commercial operations to meet the Sustainable Development Goals. Therefore, continuous research efforts are being made to find an alternative to hydrocarbon-based EDM oil. The current work is an attempt in the same direction, wherein the use of alternate dielectric media during EDM of micro-grooves on Ti6Al4 V alloys has been investigated. The performance of three dielectric gases, air, argon, and oxygen, has been evaluated. To predict the parametric relationship, investigations have been performed by altering pulse current along with pulse-on/off times by utilizing the response-surface-methodology. The material removal mechanism for different gases is expounded using analysis of debris, single-discharge crater, and recast-layer. Using oxygen instead of air or argon yielded about 19% and 51% quicker material removal rate (MRR) for identical parameters. On the contrary, using argon instead of air and oxygen yielded roughly 17% and 34% less roughness and nearly 17% and 34% less width over-cut, respectively. Optimization results showed that oxygen rendered a maximum MRR of mm /min, which is almost three times that of argon. Splat-like surface features were observed on the machined surface for oxygen.