Current development of the metal additive manufacturing sustainability – A systematic review

Metal additive manufacturing is getting interest across sectors like aerospace, automotive, and medicine. Driven by the growing stakeholders' awareness and the need to meet European Commission (EC) goals, studies evaluating the sustainability of Additive Manufacturing (AM) processes with metals are increasing. In this context, the present work aims to advance the existing knowledge on AM by systematically, and comprehensively reviewing the positive contributions of metal additive manufacturing to sustainability, and the existing sustainability evaluation methodologies applied to support AM developments, identifying current limitations and areas requiring further research. Based on the PRISMA approach, this study sought to identify the critical hotspots, available methodologies, and key achievements that may be found in the literature. The results showed that most studies focus on powder-based techniques utilising metals such as stainless steel, aluminium, and titanium alloys. The environmental assessments demonstrated that impacts may vary significantly depending on factors like part geometry, weight reduction potential, powder yield, and energy consumption. Metal additive manufacturing processes may be more expensive than conventional manufacturing, driven by material and labour costs. Finally, workers' health and safety assessments revealed potential nanoparticle exposure during manual tasks. Overall, the results showed that the sustainability of metal AM-based methods is not fully grasped, lacks standards, and relies on assumptions made by different authors, leading to variable results. Thus, further research is needed to support the stakeholders' decision-making process, namely, to develop standard approaches, and to make better comparative analyses among different studies, and frameworks assessing jointly the technical, and sustainability aspects of the metal AM parts. © 2024 Elsevier Inc.