Region-based path planning method with all horizontal welding position for robotic curved layer wire and arc additive manufacturing

For the curved layer deposition with wire and arc additive manufacturing on complex surface, the molten pool behavior and bead geometry are variant at different welding positions for the dragging effect of gravity, which lead to inconsistent layer appearance. A region-based path planning method for robotic curved layer wire and arc additive manufacturing (CL-WAAM) is developed, with which all horizontal welding position can be maintained at arbitrary region of the complex surface. The adverse effect of gravity is minimized and uniform bead appearance can be guaranteed. Firstly, with a two-stage clustering method, the complex surface was divided into a certain number of simple subregions. Then, the contour line across cluster centroid of each subregion was employed as initial path, and an adaptive bead overlapping model changed with local inclined angle was used to generate the offset curved path covering the subregion. Therefore, the overall welding paths were approximate to the contour line on the surface, and the horizontal welding position and consistent forming appearance can be achieved. Finally, three surface parts were designed to validate feasibility of the method, and the forming appearance was compared with traditional iso-parametric method and flat layer WAAM (FL-WAAM). The results suggested that the surface waviness and thickness were relatively consistent at arbitrary region of complex surface with the region-based method, and the stair-step effect appeared in FL-WAAM was significantly alleviated with the CL-WAAM. The proposed method helps achieve the uniform layer appearance deposited on complex surface, which could be widely used in the manufacturing or repairing of wear-resistant surface parts, such as the hot forging die and hydraulic turbine blade.

Automated summary

A region-based path planning method is developed for robotic curved layer wire and arc additive manufacturing, which minimizes the adverse effect of gravity and ensures uniform bead appearance on complex surfaces. The proposed method helps achieve uniform layer appearance and reduces the stair-step effect in flat layer WAAM.