Assessment of sustainability of machining Ti-6Al-4V under cryogenic condition using energy map approach

Sustainability of a manufacturing system is of significant importance to its overall efficiency and output. The issue becomes more pertinent during the machining of hard to cut titanium alloys which draws excessive amount of energy. Process map are effective tools that readily provides machinability information of materials of manufacturing importance to process planners. Titanium alloys, owing to their usage in high volumes, are well-mapped but only under dry conditions. The current research focuses on the development of energy consumption map of titanium alloy Ti-6Al-4V employing single point turning under cryogenic conditions. Cryogenic cooling is known for its convenience for green manufacturing as opposed to conventional coolant. Cutting speed and feed rate are used as variable machining parameters over a wide spectrum using full factorial design of experimentation. Energy consumption is represented by specific cutting energy due to its machine-tool independent nature. The map region was demarcated into low, moderate and high energy zones. Analysis of the developed novel map revealed underlying mechanics of machining and provided deeper insight into the factors effecting energy consumption. Energy consumption was found to be more dependent on cutting speed than feed rate. Tool chip contact length was found to decrease due to the reduction of slip region under cryogenic conditions. Analysis of chip morphology revealed that chip shear angle and compression ratio decreased with increase in cutting speed resulting in higher energy consumption. The significance of cryogenic map is also underscored in its utility on the shop floor for selection of optimum machining parameters for higher productivity in addition to its sustainable and environmental friendly nature. In comparison with dry energy map, a reduction in energy up to 16% is observed which highlights the sustainability of cryogenic energy map. The utility of cryogenic energy map can also be ascertained from the fact that productivity can be increased by 156% in terms of material removal rate by careful selection of appropriate machining parameters. Overall, the developed cryogenic map is a vital asset of manufacturing systems as it collectively serves the purpose of sustainability and cleaner production.