Lessons Learned from Fabrication of a Large Ti6Al4V Component Using Wire-Arc Directed Energy Deposition

This study investigates the wire-arc directed energy deposition (DED) of a large Ti6Al4V component, with dimensions of approximately 972 mm × 398 mm × 135 mm, pushing the limits of machine capabilities in both size and weight. A modified inherent strain method, coupled with topology optimization, was employed to design a lightweight fixture capable of resisting the high residual stresses anticipated in the part. Validation of the final fixture design was conducted by performing a quasistatic finite element analysis. The printing process had to be stopped close to the halfway point due to a burnback arc error. After some surface grinding, the printing process was resumed and completed. Although the fixture successfully maintained the part’s integrity throughout the build process, cracking occurred at the part-substrate interface because of elevated residual stresses expected from this material but exacerbated by the deposition geometry. This cracking prompted additional repair operations using the same wire-arc DED process, underscoring the importance of detailed substrate stress analysis and real-time process monitoring. The paper presents key lessons learned that led to the successful production of a crack-free Ti6Al4V component.