Tool wear, economic costs, and CO2 emissions analysis in cryogenic assisted hard-turning process of AISI 52100 steel

Toward green manufacturing, the use of eco-friendly fluids such as cryogenic coolants is necessary for machining processes, instead of the use of conventional cutting fluids. The cryogenic spray method is most popular and, it can have high efficient for cooling cutting temperature and improving tool-life during machining operations. However, few studies have reported the benefits in terms of environment, cost for the cryogenic assisted hard turning processes. This study examines the economic and environmental impact of cryogenic cooling conditions on hard-turning machining. Liquid nitrogen was used as the cryogenic coolant. We examined the spray efficiency via computational fluid dynamics and experimental validation. The optimal nozzle for cryogenic spraying was found to have an internal angle of 45°. The nozzle of internal angle 45o has the highest distance and narrow width of spray shape in the results of computational fluid dynamics analysis and the experimental observation. Flank wear lengths were monitored under dry, wet, and cryogenic cooling conditions during the machining of AISI 52100 steel (62 HRC). The cryogenic assisted process improved ceramic cutting tool-life by 3–6 times compared to dry and wet conditions. The economic effects were also evaluated based on the tool-life data obtained. The improved tool life of the ceramic cutting tool by the cryogenic process reduced the total machine operation time; it thus reduced the electricity, carbon dioxide emissions of machine operations. The implementation of cryogenic cooling can be suitable for the green manufacturing process with the improvement of the environmental impact.