Environmental assessment of wire arc additive manufacturing technology and consideration of the influence of process parameters on mechanical properties of manufactured parts

Wire arc additive manufacturing (WAAM) is an advanced technology that combines the principle of welding and additive manufacturing: metal is heated and melted by an electric arc then deposited layer by layer, which renders possible the building of large metal parts. As just-needed material is used, this technology has the potential to reduce material waste, and thus can be perceived as sustainable. However, WAAM presents environmental challenges, due to the feedstock preparation steps starting from raw material extraction, casting, forming to wire drawing. There are also safety precautions required to mitigate dangers due to emissions of harmful fumes and particles of this process (suction stations, ventilation, insulation, etc). An in-depth study would help to identify the environmental impact factors and thus provide more robust data about this process footprint on environment. The parameters of the WAAM process significantly influence mechanical properties of the manufactured parts, which are often engineered to have high-performance mechanical proprieties (particularly in industries such as aeronautics and automotive). When assessing the environmental impact of WAAM, it is essential to consider how process parameters affect both performances: mechanical and durability through the extension of lifetime of manufactured part. This technology seems to be a promising process with advantages of flexibility and obtaining parts with acceptable mechanical properties. Ongoing research is needed to clarify true added-value to reduce the environmental impact of this technology as well as its effect on the mechanical properties of manufactured parts. The present paper, first examines how previous studies have highlighted the environmental impacts of WAAM processes and evaluated their mechanical properties. It then presents a case study that incorporates a broader range of impact factors compared to those typically considered in the literature, demonstrating the importance of such approach in effecting the results of life cycle assessment (LCA). In fact results obtained at the end of this paper, show huge differences compared to those found in literature.