Forming optimization for WAAM with weaving deposition on curved surfaces

•A novel weaving deposition strategy for WAAM was developed to overcome the difficulty in formability due to the disturbance of the molten pool by gravity on curved surfaces.•The relationship between the response parameters of the woven weld bead and the forming process parameters (the surface inclined angles, welding parameters and weaving parameters) were modeled by mathematical functions and the effects of process parameters were analyzed systematically.•Multi-objective optimization based on the established model was performed to acquire a stable and consistent weld bead at any angle and any deposition direction on the curved surface. The formability and accuracy of the deposition were validated through the optimal process parameters on complex curved surfaces. A stable and consistent dimension of the weld bead is crucial and fundamental in manufacturing and remanufacturing components on the complex curved surface by the wire arc additive manufacturing (WAAM) method. In this work, a novel weaving deposition strategy for WAAM was developed to overcome the difficulty in formability caused by the gravity effect at various welding positions on complex surfaces. The relationship between process parameters and response parameters of the woven weld bead was statistically modeled through response surface methodology, and the effects of the forming process parameters and their interaction on the geometric dimensions and the formability of the woven weld bead were investigated systematically. Multi-objective optimization based on the established models was carried out to acquire a stable and consistent weld bead at any angle and any deposition direction on the curved surfaces. The experiments of WAAM with weaving deposition strategy on two curved surfaces were conducted to verify the formability of the optimal forming process parameters. Results indicated that the effects of forming process parameters on the geometric dimension and formability of the woven weld bead are quite complicated, with various influential trends and amplitudes, and strong nonlinear interaction effects. Deposited by the optimal parameter, a stable and consistent weld bead with the dimensional deviation and unevenness index of bead surface being less than 1.55% and 0.035 can be obtained on a curved surface. The overall thickness of multi-bead deposition on curved surfaces is evenly distributed between 2.4 mm and 2.9 mm, with a maximum variation of 0.5 mm between the peak height and valley h