Method for load-capable path planning in multi-axis fused deposition modeling

Additive Manufacturing (AM) technologies have evolved from a niche application for rapid prototyping into a crucial technological and economically significant industry for functional parts. However, many processes cannot guarantee the required component properties for industrial applications. Here, anisotropic strength properties introduced in Fused Deposition Modeling (FDM) are major constraints. These production-related strength properties originate in the weak bonds between plastic beads and thus between layers, which considerably affects the strength of the part in multi-axial stress conditions. Multi-axis FDM printing enables the diminishment of this effect by using Curved Layer Slicing. However, suitable path planning tools have not been developed to realize this approach on an industrial level. This paper describes a method for strength optimization under consideration of the manufacturing boundary conditions. This path planning method is based on a subdivision of the CAD part into sub-volumes, which comprise homogeneous sets of principal stress trajectories, as determined by the Finite Element Analysis. Subsequently, the sub-volumes are sliced individually using a Curved Layer Slicing approach and paths on the different layers are aligned with the principal stress trajectories. This method generates and uses strength-oriented meta data, which closes a crucial interface between CAD, CAM and AM processes.