Co-optimization for 3D Printing Porous Structures and Paths under Manufacturing Constraint

Porous structures are widely used in engineering due to their superior comprehensive properties. Compared with traditional equal-material and subtractive manufacturing, 3D printing, as a process of additive manufacturing technology, exhibits significant advantages in manufacturing flexibility and efficiency for porous structures. However, the complicated topological form results in discontinuity and uneven filling of printing paths, thus decreasing the fabrication quality and mechanical performance. A co-optimization of structure and path based on Voronoi skeletons is developed to improve this situation. To generate porous structures suitable for 3D printing, path optimization is synergistically considered by applying a manufacturing constraint in the structural design. Periodic or graded Voronoi cells are constructed according to the mechanical condition, aiming to optimize the material layout. Discontinuous paths, which are generated via offsetting Voronoi skeletons, are connected to fulfill global continuity by introducing a depth-first search method. The calculation result indicates that the porous structures generated by the proposed co-optimization method are evenly fabricated by a path without any intersection and solved the issue of the integral multiple of path width. Additionally, printing defects caused by path breakpoints and null nozzle travel are eliminated. The feasibility of the proposed method is validated by the material extrusion additive manufacturing technology. The mechanical test demonstrates that the mechanical performance of porous structures optimized by the proposed method are higher than that of models fabricated by the conventional method due to better printing quality of the former. This research plays a significant role in fulfilling high performance, thus promoting the integrated design and fabrication of material-structure-performance for 3D printing porous structures. © 2024 Chinese Mechanical Engineering Society. All rights reserved.