Mapping-based Path Planning on Large-Curvature Surface for Multi-axis 3D Printing

Large-curvature surfaces made of lightweight plastic have been widely used to pursue the excellent aerodynamics and mechanical characteristics of vehicles. Robot-assisted 3D printing method has 6 degrees of freedom and offers potential to manufacture complex composites. However, one of the vital challenges is the printing path planning on large-curvature surfaces. To solve the challenge, this paper proposes a mapping-based path planning method. Based on topological optimized 2D graphs, the medial axis of graphs is extracted to manipulate printing paths to follow stress transmission directions. Then, a planar quadrilateral (PQ) mesh method has been applied to generate deformed quad grids on the topology graphs. The meridians and parallels of the PQ meshes have been separated and the one which follows the stress vectors has been transformed to Zigzag paths. By mapping the Zigzag path on a large-curvature surface, the in-plane printing paths can fit a complex free-form surface faithfully. Several study cases of the large-curvature geometries have been validated using a robot-assisted 3D printing technique. Compared with the traditional method of using triangular mesh and direct mapping method, this method can generate a smooth Hamiltonian path on large-curvature surfaces to achieve a curved slicing.