Mechanical Behavior of <scp>PLA</scp> Based Composite Filaments Fabricated by <scp>FDM</scp> : Role of Build Orientation and Reinforcement Type

ABSTRACT This research highlights the necessity of concurrently evaluating filament type and printing orientation to optimize the balance between stiffness and ductility. Mechanical properties of polylactic acid (PLA) based composite filaments (neat, carbon fiber (CF), wood, ceramic, and foaming agent (FA)) manufactured via Fused deposition modeling (FDM) were experimentally investigated. Specimens were fabricated at 0°, 30°, 45°, 60°, and 90° build orientations and tested according to ASTM (D638 (Tensile), D790 (Three point bending), D6110 (Charpy), and D2240 (Shore D)) standards. Results demonstrated that mechanical performance is significantly influenced by material composition and build orientation. Tensile testing revealed that 60° oriented CF reinforced specimens exhibited the highest elastic modulus (4.31 GPa), whereas PLA FA at 60° yielded the lowest (0.87 GPa). In three point bending, 0° Neat PLA achieved the maximum flexural strength (74.48 MPa), while 60° PLA FA recorded the minimum (35.32 MPa). Charpy impact analyses indicated maximum toughness in 0° Wood specimens (19.18 kJ/m 2 ) and the lowest at 60° orientation (2.11 kJ/m 2 ). Furthermore, 45° Ceramic reinforced specimens attained a maximum surface hardness of 57 HD, contrasting with the minimum 15 HD in 0° PLA FA. The 90° build orientation significantly reduced mechanical strength across material groups due to poor interlayer adhesion.