Optimal deposition orientation in fused deposition modeling for maximizing the strength of three-dimensional printed truss-like structures

Whether for producing prototypes or functional parts by additive manufacturing, the fused deposition modeling is the most commonly used technique. Nevertheless, not only the hobbyist but also the industrial three-dimensional printers produce parts that suffer from anisotropy in their mechanical properties imposing important limitations on the strength of the manufactured piece. The aim of this work is to propose a strategy for determining the optimal build surface orientation of three-dimensional truss-like structures manufactured using fused deposition modeling. This can be achieved by minimizing the norm of the dot products of the normal direction of the deposition plane (build surface plane) and the directions of the tensile forces. Since three-dimensional trusses are subjected to tensile forces in different directions, a multi-objective cost function was proposed. Moreover, these structures might present rotational symmetry, which should be considered as design constraints. In this work, two three-dimensional truss-like structures were investigated. The nature of the optimization is case dependent and solvers were selected accordingly. Experimental campaigns were carried out for evaluating the specimens manufactured using fused deposition modeling. It could be concluded that higher yield tensile strength could be achieved by adopting the optimal deposition plane. This result demonstrates the applicability of optimization techniques for improving additive manufacturing results.