Link: https://amgta.org/wp-content/uploads/2021/01/State-of-Knowledge-on-the-Environmental-Impacts-of-Metal-Additive-Manufacturing.pdf

Introduction:

Metal additive manufacturing(AM)is a large and growing market, estimated at$1 billion in 2020, and predicted to grow over 27% per year for the next several years(Grand View Research, 2020).  Compared to conventional manufacturing (CM), it can enable the production of new complex shapes, can consolidate assemblies into single parts, and can enable lighter or functionally optimized designs.  For example, GE notably used AM to reduce a turboprop engine from an 855-part assembly to the only 12-part Catalyst™ engine with improved power and fuel efficiency over its predecessors, shown in Figure 1 (Dusen, 2017). Metal AM also enables manufacturing with advanced materials, such as the cobalt chromium ceramic alloy used to print a jet engine nozzle which could not be produced by conventional methods (Beyer, 2014). AM shows clear functional and economic advantages over CM for some circumstances; does it also show environmental advantages? And if so, are these advantages in the same circumstances with economic or functional advantages? How can organizations plan responsible strategies for AM in a world increasingly affected by climate change and resource scarcity?  What research is still needed to ensure a sustainable future for metal AM?

This report synthesizes existing academic literature comparing the environmental impacts of metal AM with conventional manufacturing methods and provides context with impacts of common metals and processing methods found in a materials database.  Its goal is to summarize current knowledge and identify areas where information is sparse, unclear, and much needed. Life-cycle assessments were especially sought, as they can provide a comprehensive picture of the impacts of manufacturing technologies, measuring multiple types of environmental impacts from cradle to grave.  The report’s structure is as follows: The Methods section describes how the literature review and material database knowledge was gathered and analyzed.  The Results and Discussion section discusses the data from the database and literature, comparing AM and conventional manufacturing by life cycle stage, including embodied material impacts,processing impacts,the change in product usage impacts due to light-weighted AM designs, and other considerations.It also compares AM to conventional manufacturing by industry sector, including aerospace, automotive, and medical devices.  Finally, the Conclusion summarizes key takeaways for decision-makers considering what technologies, assessment tools,and research areas to pursue.