Effect of infill direction on the mechanical and fracture characteristics of 3D printed materials

Fused Deposition Modeling (FDM) is a widely adopted additive manufacturing method, favored in both industrial and academic fields due to its affordability, ease of operation, and compatibility with a variety of thermoplastic materials. Despite its advantages, components produced via FDM often exhibit anisotropic mechanical behavior influenced by printing parameters. This study experimentally examines how print orientation affects the fracture behavior of PLA (Polylactic Acid) specimens fabricated using FDM. Samples were printed at various orientation angles (0°, 15°, 30°, 45°, 60°, 75°, and 90°) and tested under uniaxial tensile, flexural, and Single Edge Notched Beam (SENB) loading to observe fracture modes. The findings show that print orientation has a significant impact on tensile strength, flexural strength, and fracture toughness. Specimens printed parallel to the load direction demonstrated enhanced mechanical performance, whereas those printed perpendicular to it experienced brittle failure due to weak interlayer adhesion.