Effect of fill pattern on flexural performance of FDM printed PLA

In most biomedical devices, such as fracture fixation devices and medical tools, the printed part is subjected to complex loadings that involve large deflections instead of large strains. Among various FDM tool path parameters, the fill pattern has a critical role in controlling voids and raster bonding. This work highlights the flexural performance of the PLA-printed part based on various fill patterns, such as concentric, linear, Hilbert, raster angle 45o, alternate pattern (0o/45o), and concentric pattern with holes resembling bone plate. Based on deposition paths, the dimensional changes and interlayer adhesion were analyzed before and after annealing. The flexural performance was evaluated using quasi-static three-point and four-point bend tests and dynamic flexural tests under temperature sweep. The annealed samples exhibit improved flexural strength regardless of infill pattern and loading conditions, with the concentric pattern showing better performance in both static and dynamic tests.