Optimising the operational parameters and conditions to enhance the environmental sustainability of turning operation

Abstract

The manufacturing sector accounts for nearly 40% and 25% of global energy and resources consumption respectively. The die and mould manufacturing (DMM) sector, contributes largely to the energy and resource consumption in emerging economies. Turning is a popular and essential mode of machining within this sector. Furthermore, operational energy usage and metalworking fluid (MWF) consumption of turning have been identified as the key sources of environmental impacts in this process. However, there is a lack of evidence on analysing environmental impacts of lathe operations in the DMM sector compared to milling operation. Therefore, the purpose of this study is to identify and analyse the life cycle environmental impacts of the commercial turning operation. A series of case studies was conducted in DMM centres to explore the state-of-the-art industrial turning operation. Then, a set of experiments was designed using the Taguchi L 9 method, considering the mostly used workpiece material, cooling condition and cutting parameters. Experiments were performed to evaluate the energy consumption, metalworking fluid (MWF) consumption, surface roughness and material removal rate during turning of AISI P20 with both wet and dry machining. A life cycle assessment (LCA) was performed using SimaPro LCA software with Ecoinvent database version 8.5 to assess the environmental performance of turning. A multiresponse

optimisation was performed using Grey-based Taguchi method to identify the optimum operating conditions. The results show that turning with wet machining yields better machining and environmental performances compared to dry machining. The largest portion of the energy is consumed for non-productive operations. The LCA results reveals electrical energy as the highest contributor under most of the impact categories. The workpiece material, AISI P20 and cutting insert material show significant contributions to aquatic ecosystems and resource consumption. However, the contribution of MWF on the midpoint impact categories is negligible. Further, the research presents optimum turning parameters to obtain better machining performances while maintaining lower environmental footprint in the context of turning of AISI P20 with wet machining.