Automated arc additive manufacturing: defect suppression, process research, and application

CMT+Pulse arc additive manufacturing encounters challenges, including poor dimensional accuracy, high defect susceptibility, and insufficient mechanical performance. To overcome these limitations, this study develops a novel automated CMT+P arc reciprocating additive manufacturing strategy with dynamic flexible control and short dwells at arc start/stop points to maintain low heat input. This method effectively suppresses weld bead protrusions and concave defects. Results show that the S2-step method improves forming quality, reducing height discrepancies at arc start/stop positions by 21.43% vs. the two-step method. Uniform hardness (max 201HV0.5), EL=61%, YS=324 MPa, UTS=679 MPa, high strength‑ductility synergy, anisotropic mechanical behavior, and ductile fracture are achieved. A large component (1000 mm height, 456 mm outer diameter, 55 mm wall thickness) with a smooth surface is successfully fabricated. This work provides a new approach for regulating microstructure and mechanical properties in robotic arc additive manufacturing, supporting efficient, low‑energy, high‑performance fabrication of large‑scale metal components.