Path planning for curved layer fused deposition modeling of continuous fiber reinforced structures with iso-void depth

At present, additive manufacturing of continuous fiber-reinforced composites (CFRCs) mainly adopts planar fiber layout. The development of multi-axis additive manufacturing systems provides unprecedented opportunities for the fabrication of composite structures with non-planar fiber layouts. This paper explores a multi-axis curved layer fused deposition modeling (CLFDM) process for CFRCs. Based on the drum-shaped deposition cross-section, a curved layer theoretical deposition model with equal void depth that satisfies uniform overlap is constructed. A path planning method for continuous fiber curved layer is proposed based on the theoretical deposition model. The accurate equal error step size calculation is performed under the change of the surface normal curvature and the curve curvature, achieving interference-free and equal error printing path discretization. Using 6-axis robot integrated with a dual-nozzle printing system, continuous fiber CLFDM is realized through its multiple degrees of freedom. Verified by computer simulation and physical printing experiments, the algorithm in this paper has considerable feasibility for various surface shapes, effectively enabling the manufacturing of continuous fiber curved layers with high fiber volume fraction. Comparative results of mechanical experiments show that the failure loads of the uniformly overlapped continuous fiber curved layers increased by 39.8 % and 89.2 %, and the stiffness increased by 47.8 % and 73.2 %, respectively. This provides new insights for the exploration of composite materials with complex curved fiber layouts.