Holistic Life Cycle Assessment of Cryo-Assisted Drilling of Additively Manufactured Inconel 625

This study evaluates the machinability of Inconel 625 using solid carbide cutting tools under cryogenic LCO 2 conditions for both wrought and WAAM-produced workpieces, focusing on tool wear, power consumption, surface roughness, and environmental impact. Experiments conducted at 45 mm/min speed, 85 mm/min feed rate, and 3.5 mm hole depth revealed that TiAlN-coated drills (Drill 1 and Drill 2) outperformed TiN-coated drills (Drill 3). Drill 1 exhibited gradual wear over 18 holes, while Drill 3 experienced catastrophic failure after just three holes, wearing up to 11 times faster. Power consumption analysis showed that Drill 1 consumed 15.34% less power than Drill 3 for WAAM and 7.80% less for wrought specimens, with Drill 2 achieving even greater reductions of 23.40% and 16.91%, respectively. Surface roughness (R a ) measurements indicated consistent performance for Drill 1, with values ranging between 0.3–0.7 μm, compared to Drill 3’s higher and rapidly degrading values of 0.4–0.9 μm. Life Cycle Assessment (LCA) using the ReCiPe 2016 Midpoint (H) methodology revealed that WAAM processes had higher environmental impacts than wrought ones due to their energy-intensive nature. However, TiAlN-coated drills significantly mitigated these impacts, reducing energy consumption and environmental burdens. This study highlights the superior performance and sustainability of TiAlN-coated tools in machining hard-to-cut materials like Inconel 625, emphasizing the importance of tool selection and process optimization to enhance efficiency, reduce costs, and minimize environmental impacts in advanced manufacturing applications.