An Environmental Sustainability Assessment of a Milling Process using Life Cycle Assessment

Abstract

The growing demand to reduce the environmental burden has encouraged manufacturers as well as users to pursue various green machining strategies and technologies that enable increasingly efficient use of limited resources. Assessment and quantification of the environmental impacts caused by machining processes serves as the foundation towards the visualization and mitigation of environmental emissions. The research community has addressed the life cycle analysis of machine tools to quantify their environmental emissions during their life cycle, but the environmental impacts of the actual machining process have not been addressed effectively. This study presents the life cycle analysis of a milling process to evaluate and quantify its environmental impacts during raw material extraction, manufacturing, transportation and end of life phases for the manufacturing a sample product. The environmental impacts were assessed in both endpoint and midpoint impact assessment categories using the ReCiPe method. Raw material production, electricity consumption, cutting fluid production and disposal, chip processing and compressed air production are identified as major factors causing environmental impacts. It is evident from the analysis that energy consumption plays a major role in environmental impacts using the milling process directly (for material removal) and indirectly (compressed air production and the heating, ventilation and air conditioning system). Therefore, reduction in energy consumption plays a major role in reducing the environmental impacts of the milling process. Sensitivity analysis has been carried out to assess the robustness of the results obtained from the machining life cycle assessment study. This analysis can be used as a foundation for the formulation of key plans for the improvement of environmental sustainability in machining processes.