Deposition path planning and stress control for gridding thin-walled titanium alloy parts fabricated by wire-arc additive manufacturing

Wire-arc additive manufacturing (WAMM) is an emerging manufacturing technology that employs metal wire as the raw material and arc as the heat source. It offers advantages in fabricating large and complex parts. Nevertheless, it still faces challenges, including prolonged fabrication cycles, intricate path planning, and substantial residual stress. In this study, we explore the optimization of the manufacturing path for wire-arc additive manufacturing when fabricating complex structural components, aiming to mitigate the significant residual stress and strain induced by suboptimal manufacturing paths. Finite element software is utilized to optimize the manufacturing path, and a unit body of a grid component with excellent forming quality has been successfully produced using the optimized path. Through finite element analysis, it can be revealed that for the unoptimized path, the equivalent residual stress at the thin-wall after cooling reaches 361 MPa, while that at the nodes after cooling is 666 MPa. In contrast, for the optimized path, the equivalent residual stress at the thin-wall after cooling is 206 MPa, and the equivalent residual stresses at two nodes after cooling are 260 MPa and 427 MPa, respectively. Compared to the unoptimized path, the optimized path leads to a 61% reduction in residual stress at the nodes and a 43% decrease in stress at the thin-wall. Moreover, the difference in residual stress between the nodes and the thin-wall is smaller than that of the unoptimized path, resulting in less deformation and fewer defects caused by residual stress. The grid component unit body fabricated using the optimized path exhibits well-combined melt tracks and superior forming quality, with no discernible residual stress deformation. This effectively validates the feasibility of the optimized path in controlling residual stress during the wire-arc additive manufacturing of grid components.