Life Cycle Assessment of Additively Manufactured Indexable Milling Tools with Adapted Cutting Fluid Supply

Abstract

High-pressure cutting fluid (CF) supply in milling allows higher productivities and results in extended tool life and higher process reliability. On the other hand, the use of CF results in high energy consumption of the CF supply units. By using the additive manufacturing (AM) technique Laser Powder Bed Fusion (PBF-LB), steel-based basic bodies for indexable cutting tools can be manufactured including complex internal structures with new geometrical possibilities. Thus, the internal CF supply can be redesigned, lowering fluid losses within the supply channels and focusing the fluid for a more efficient and effective cooling and lubrication of the contact zone. This study focuses on the ecological evaluation of PBF-LB manufactured indexable tangential milling tools with adapted CF supply for roughing of Ti-6Al-4V according to DIN EN ISO 14040/44. The ecological competitiveness of the newly developed tools against a conventionally manufactured reference tool was evaluated. Two system boundaries were analyzed, considering the cradle-to-gate as well as the cradle-to-grave life cycle. Even though the calculated environmental impact for the manufacturing of the AM tool exceeded the conventional tool, the improved functionality, increased tool life and reduced energy consumption during service life of the tool led to a reduction in the overall ecological costs.