Recent research progress on various cooling and lubrication techniques used in sustainable hard machining: A comprehensive review

In recent research, hard machining is an essential manufacturing technology to meet the demand for various industrial product quality and precision. Several key issues like higher heat generation, higher tool wear, higher cutting force and inappropriate surface quality were found in hard machining. Researchers have examined several hard machining-related issues and developed their own suggestions for solutions. It was attempted to research the effects of tool geometry, tool materials and coatings, cutting parameters, and different cooling strategies (coolant and its delivery techniques) on various machinability responses, such as tool wear, tool life, cutting forces, surface roughness, chip morphology etc. In this review article, the different methodologies of cooling and lubrication utilized during hard machining processes have been analysed and their potential application towards sustainable machining is explored. This paper addressed the needs, challenges, and trends towards achieving sustainable hard machining of hard-to-cut materials through the application of dry, minimum quantity lubrication, cryogenic and nanofluids-assisted minimum quantity lubrication cooling strategies. It will be helpful to achieve environmental, economical, ecological and societal benefits to justify sustainable machining. Minimum quantity lubrication hard machining and nano-cutting fluid-assisted minimum quantity lubrication hard machining for sustainability will be immensely beneficial for the replacement of traditional cooling strategies for machining hard-to-cut hardened steel. Furthermore, different computational methods adopted in hard machining for optimization and modelling were also explored to get the optimal solution for industrial applications.