Comparative analysis of die-sinking EDM and near dry EDM for machining difficult-to-cut materials: Stainless Steel 316 and Hastelloy C276

This paper explores the demand for precision machining of challenging materials and the limitations of traditional electro discharge machining (EDM). To overcome environmental impact and surface finish constraints, near dry EDM has emerged as a promising alternative. The study presents a comparative evaluation between die-sinking EDM and near dry EDM for machining Stainless Steel 316 and Hastelloy C276. Key performance parameters, including material removal rate (MRR), surface roughness (SR), and tool wear rate (TWR), are analysed to optimise the process. A novel dielectric mixture of glycerin and air is used in the experimental work. Results demonstrate that near dry EDM offers a superior surface finish and reduced tool wear; making it an environmentally friendly option. Near dry EDM achieved a 40% reduction in surface roughness for both alloys compared to die-sink EDM. Additionally, TWR showed a significant 40% decrease for SS316 and a notable 50% decrease for Hastelloy at high parameter settings in near dry EDM. Although a slight reduction in MRR is observed, the overall benefits position it as a promising technique for machining challenging materials. The findings provide valuable insights for selecting the most suitable EDM approach, enhancing modern manufacturing capabilities.