Layout and geometry optimization design for 3D printing of self-supporting structures

As the demand for high-performance structures in various scenarios continues to rise, the complexity of engineering structures also increases, necessitating the development of advanced design methods and the additive manufacturing (AM) of sophisticated structures. While the layout optimization method based on the ground structure technique can produce optimized designs, the gravity-induced overhang effect during the printing process often requires additional support materials. The use of additional support materials during the printing process can result in higher material costs or the need for post-processing to remove the support structures, significantly hindering the adoption of AM in practice. This paper presents an optimization framework to obtain self-support optimization designs and provides a practical validation for the effectiveness of the proposed framework. Firstly, a self-support point-line structure is obtained via the layout and geometry optimization, considering overhang constraints. Secondly, the point-line structure is transformed into a physical model with nodal expansion considered (i.e., taking into account the overlapping of members at nodes). Finally, the physical models are sliced and printed using both a plastic Fused Deposition Modeling (FDM) printer and a metal Wire Arc Additive Manufacturing (WAAM) printer. The results confirm that the proposed process is effective for both plastic and metal printing, demonstrating its exceptional versatility.