Abstract
Fused deposition modeling (FDM) is increasingly used to manufacture functional polymer components, but the mechanical performance of printed parts is strongly influenced by process parameters. This study examines the effects of build orientation, infill density, infill pattern, and printing speed on the tensile behavior of polylactic acid (PLA) specimens. Dog-bone samples with ISO 527-2 type 1A geometry were printed using three build orientations (A—horizontal, B—vertical, C—lateral), two infill densities (40% and 70%), two infill patterns (triangle and tri-hexagon), and two printing speeds (40 and 60 mm/s). Tensile tests were performed to determine Young’s modulus, yield stress, ultimate tensile strength, and elongation at break. The lateral (C) orientation provided the highest mechanical performance, with an average ultimate tensile strength of 47 MPa and a Young’s modulus of 2.9 GPa, compared to 33 MPa (E ≈ 2.4 GPa) for the horizontal (A) orientation and 16 MPa (E ≈ 2.0 GPa) for the vertical (B) orientation. For horizontally printed specimens, a 70% infill consistently increased tensile strength relative to 40% infill. The combination of 70% infill, triangular pattern, and 40 mm/s printing speed (A70T40) achieved the highest ultimate tensile strength among the infill configurations. These findings highlight the importance of selecting appropriate printing parameters when PLA components are intended for load-bearing applications.
Keywords: Additive manufacturing; PLA; tensile testing; mechanical properties; infill pattern; infill percentage; build orientation