Straight skeleton filling methods for thin-walled parts

Wire and arc additive manufacturing (WAAM) has emerged as a promising technique for manufacturing parts with slender features and thin-walled structures. Nevertheless, the utilization of conventional contour-parallel tool paths, with constant offset intervals from the model boundary, leads to filling defects such as underfilling and overfilling. These defects detrimentally affect manufacturing speed, model accuracy, and the structural integrity of the final products. To address these challenges and enhance manufacturing speed, model accuracy, and defect reduction, this paper presented two path-planning methods specifically tailored for thin-walled features. Both proposed methods were built upon the concept of the polygon straight skeleton. The first method was specifically tailored for simple thin-walled parts with a uniform wall thickness, enabling the generation of both closed and open paths. This approach effectively reduced the path length and significantly enhanced printing efficiency compared to conventional contour-parallel tool paths. The second method, in combination with the level-set method, was designed to tackle thin-walled parts with non-constant wall thickness, enabling the generation of paths with variable deposition widths. This adaptive approach ensured precise and efficient material deposition. To verify the efficacy of the proposed path planning methods, a series of printing experiments were conducted for the first method, while comprehensive planning results were obtained for the second method. The proposed path planning methods demonstrate potential applicability across various geometries.