LIFE CYCLE ASSESSMENT TO ACHIEVE SUSTAINABILITY IN PRE- AND POST-PROCESSING: WAAM VS. WROUGHT TI-6AL-4V

The shift toward sustainable manufacturing has intensified the necessity for examining the ecological impact of different production methods. This article conducts a cradle-to-gate Life Cycle Assessment (LCA) of ‘conventional wrought processing’ and ‘Wire Arc Additive Manufacturing’ (WAAM) for Ti-6Al-4V alloy, followed by post-processing under cryogenic (LCO2) cutting conditions. The environmental impact assessment covers key indicators, including climate change potential, resource depletion, terrestrial ecotoxicity, and human toxicity. The results reveal that WAAM exhibits a significantly higher environmental burden, with 261% greater terrestrial ecotoxicity, 32% higher climate change impact, and 104% more metal resource depletion compared to wrought Ti-6Al-4V. Additionally, WAAM consumes 25% more fossil-based energy and 44% more water, highlighting its higher resource intensity. The human toxicity assessment indicates that WAAM results in 36% greater carcinogenic toxicity and 19% higher non-carcinogenic toxicity, largely attributed to increased emissions from titanium extraction and tungsten carbide tool production for post-processing. While WAAM offers a reduction in material waste through near-net-shape manufacturing, this benefit is offset by its excessive energy consumption and emissions. The power consumption during drilling is nearly identical for both processing routes, reinforcing that pre-machining (raw material) factors dominate environmental impact, while tool wear in WAAM is twice as high, leading to increased resource consumption. These findings emphasize the need for process optimization to further improve the sustainability of titanium alloy manufacturing.