On the importance of property-dependent environmental impact assessment for sustainable additive manufacturing

The assessment of the environmental impact of additively manufactured parts is difficult due to the hard-to-compare system boundaries. This study proposes a novel property-dependent option for the comparison of additively to conventionally produced parts based on the life cycle assessment (LCA) of two different designs of structural components for energy-absorption applications. While the optimized additive manufacturing (AM) lattice structure led to significant reduction of global warming potential (GWP), cumulative energy demand (CED), and material footprint (MF) (−45%, −51% and −56%, respectively), additively manufacturing the standard design led to an increase of those environmental indicators (+33.9%, +33.1% and +34.6%, respectively) as compared to the conventionally manufactured standard design. It is demonstrated that the environmental impact of metallic components is only reduced by AM if the freedom of design offered by these techniques is utilized to realize weight reduction and, more importantly, that this design must be based on critical part properties. Especially, argon consumption during atomization was found to drastically increase the environmental impact. Consequently, the material yield during powder atomization and AM, combined with minimized gas consumption, can pave the way towards more sustainable AM.