Abstract
There is a need to replace non-sustainable conventional coolant (emulsion) with eco benign high-performance cutting fluids such as biodegradable nanofluids that exhibit sufficient lubrication and cooling properties. Also, the sustainability performance of titanium-based alloys can be improved with the geometric alteration on the tool rake zone and by the proper cooling-lubrication mechanism. In the present study, the holistic sustainability of external turning of titanium (Ti-6Al-4V) alloy under two different cutting environments (Al-GnP nanoparticle-based minimum quantity lubrication (MQL) with textured carbide tools and conventional emulsion) is investigated. Novel empirical models for cycle time, machining power, embodied and electrical energy consumption carbon emission, and production cost were developed. For both environments, machining experiments were performed until the cutting tool reaches its life. All sustainable indicators were measured and compared with the conventional process. Results showed that textured carbide cutting tools in the presence of Al-GnP nanoparticle-based MQL-assisted machining (hybrid process) are sustainable environmentally and economically. At the very-high (130 m/min) cutting speed, the sustainable hybrid machining process consumed 1.50% less specific cumulative energy (S_CEC), emitted 5.96% less specific CO2, and incurred 4.33% less specific production cost (S_PC) compared with flood-assisted machining. Finally, it is concluded that the presence of hybrid Al-GnP nanofluids in line texture has the potential to act as lubricant/coolant in turning processes.