University Laboratory-Scale Carbon Footprint and Cost Comparison of Atomized and Short-Chip-Milled Aluminum Powders for TPU–Al Composite Specimens

This study compares the cradle-to-gate carbon footprint and production cost of TPU–Al composite specimens manufactured by fused filament fabrication (FFF) using two aluminum-powder sourcing routes: commercial gas-atomized powder imported from the United Kingdom and powder produced by low-energy grinding of 7075 machining chips under laboratory conditions (TRL 3–4). Stage-resolved inventories were compiled for both systems, and an attributional life cycle assessment (LCA) focused on climate change (CO 2 -eq) was performed. The results show that Scenario 1 is dominated by the electricity demand of extrusion and printing, whereas Scenario 2 is overwhelmingly dominated by the high-energy intensity of chip grinding. Recycling–allocation rules strongly affect the comparative outcome: under a 100:0 recycled-content perspective, the recycled-powder route appears favorable, but under 50:50 or 0:100 allocation, it becomes substantially more carbon-intensive. Cost analysis indicates that chip-derived powder is economically competitive due to avoided atomization and importation costs. Limitations include laboratory-scale inefficiencies and the absence of comparative mechanical testing.