Innovative Approaches to Sustainable Machining of Inconel 718 — Exploring Green Metal Working Fluid Alternatives and Delivery Strategies

This study investigates machining of the Inconel 718 superalloy in high-speed regime, focusing on sustainable enhancements through eco-friendly metal working fluids (MWFs) and innovative delivery methods. Using coated carbide tools, machining was conducted under dry conditions and with cold air and water vapor MWFs. The impact of conventional external nozzle delivery versus innovative through-tool delivery of MWFs was also explored. Results show that using water vapor as an MWF improves surface integrity significantly, reducing surface roughness by up to 55.86% and residual stresses by 123.36% compared to dry machining. Furthermore, high-pressure cold air delivered through-tool achieved a 48.97% improvement in surface finish and reduced residual stresses by 87.73% relative to dry conditions. Across all tests, through-tool delivery methods resulted in smoother surfaces with fewer surface alterations, indicating improved cooling and lubrication effectiveness. The study highlights the superiority of water vapor MWF and through-tool delivery for optimizing productivity and sustainability in machining processes, offering valuable insights for industrial applications.