Evaluating the sustainability pillars of energy and environment considering carbon emissions under machining of Ti-3Al-2.5 V

This paper investigates the turning of Ti-3Al-2.5 V with coated carbide tools under different cooling/lubricating environments to identify the sustainable and improved cooling/lubrication technology. Five different cooling/lubrication conditions (dry, pressurized compressed air-assisted wet cooling, cooling with Ranque-Hilsch-vortextube (RHVT), conventional MQL, and wet oil cooling) were selected and turning performance was evaluated in terms of air quality of the worker's breathable/working zone, energy consumption, carbon emissions, tool wear, surface roughness, and chips analysis. From experimentation, it was found that under MQL the value of tool wear and surface roughness was lowest as compared to other cooling/lubricating conditions. But the generation of particulate matter of PM2.5 (150-305 mg/m(3)) under MQL was on alarming scale as compared to other cooling/ lubricating environments. Further, energy consumption and carbon emissions with MQL was found to be lowest followed by RHVT, which was mainly due to effective cooling/lubrication provided by the lubricant in MQL and chilled air under RHVT. The comparison of RHVT and MQL environments indicate just 1.6-1.4% increment in energy consumed with the use of RHVT under both tested speeds. Further, under RHVT state 45%-56% reduction in carbon emission (at both MRR) in contrast to dry turning was observed. The generation trend of average PM2.5 particles under RHVT was comparable with that achieved under dry conditions. Results of the study clearly indicates that RHVT can act as sustainable cooling/lubrication techniques in terms of environmental, economic and technological aspects for turning of Ti-3Al-2.5 V.