A comparative environmental assessment of an automotive component processed by laser powder bed fusion (LPBF) versus CNC machining, with steel powder reuse impact analysis

The study reported in this paper presents a comparative life cycle assessment (LCA) of a maraging steel automotive hub carrier manufactured through using Laser Powder Bed Fusion (LPBF) metal additive manufacturing (metal AM) versus conventional Computer Numerical Controlled (CNC) machining. The manufacturing processes are modelled with primary data collected from dedicated metal AM unit and machining experts. These primary data served as the foundation for creating trustworthy LCA database specific to our metal AM Unit activities, from powder storage, through part manufacturing, to diverse post-treatment operations stages. The study covers the full product life cycle from raw material extraction to end-of-life recycling. Results show that while LPBF offers substantial reductions in material consumption and mineral resources depletion, its environmental superiority over machining is conditional. LPBF with use of 83.7% recycled powder shows lower global warming potential (GWP) and fossil resources depletion than CNC machining. However, when exclusively new powder is used, LPBF becomes significantly more impactful, particularly due to energy-intensive powder production. A parametric analysis reveals that integrating at least 52% recycled powder charge into the LPBF 3D printer is critical for achieving a better environmental profile than CNC machining. This study underscores the importance of the powder recycling rate evaluation as one key parameter for sustainable adoption of metal AM, especially through PBF techniques in industry. • Crucial influence of powder recycling rate on the environmental impact of LPBF • Robust primary manufacturing data from LPBF highlighting the disparity in published data • LPBF cuts environmental impact versus CNC if powder is sufficiently recycled (>50%).