Stress-based tool-path planning methodology for fused filament fabrication

Abstract

Tool-path planning has a considerable impact on the quality of components printed by fused filament fabrication (FFF). This research proposes a path generation strategy based on the orientations of the maximum principal stresses. According to stress calculations from finite element analysis (FEA) of the components, tool-paths, which are programmed as parallel to the maximum principal stress directions, are constructed with the depth-first search (DFS) method and a connection criterion. The breakpoints in the tool-paths are then eliminated by connecting adjacent tool-paths. The Dijkstra algorithm is engaged to reduce the nozzle jump distance and shorten the production time. Stretching tests of different specimens printed with the developed path generation algorithms demonstrate that the model with the stress-based path has better mechanical performance. The digital image correlation (DIC) method and scanning electron microscopy (SEM) are employed to observe the fracture processes and fracture surfaces, respectively. Corresponding results of DIC and SEM reveal that different path filling forms exhibit variable failure patterns because of filament anisotropy. The filling fraction is calculated and indicates that the deposition quality of the advanced path is not compromised. This work provides a synthesis methodology for improving the mechanical performance of 3D printing products.