Investigating the Effect of Processing Parameters on Mechanical Behavior of 3D Fused Deposition Modeling Printed Polylactic Acid

Additive manufacturing by fused deposition modeling (FDM) is a simple and low-cost manufacturing technique for complex shapes and designs. The present study characterizes polylactic acid (PLA), printed by FDM, and analyzes the effect of processing parameters such as build orientation, infill density and infill pattern on the mechanical properties by uniaxial tensile and compression tests. The tensile and compression studies on different build orientations imply significant anisotropy of the printed parts. An increase in infill density (25, 50, and 75%), though increased printing time, resulting in a prominent enhancement of compressive properties. However, the compression test on different infill patterns has shown that these patterns have a small effect on mechanical properties. Among them, gyroid with 75% infill, printed along 90 degrees orientation imparted significantly higher compressive properties (strength, 27 MPa and modulus, 658 MPa). The pore morphology and homogeneity in pore distribution have been studied to develop porous PLA parts for tissue engineering applications. The SEM analysis of gyroid patterns at different infill densities revealed the uniform pore distribution and effective inter-layer bonding with fewer voids. Microstructural studies on gyroid and CS patterns by micro-CT imaging have shown the positive correlation of obtained porosity with the theoretical values. Overall, the present study provides a comparative analysis of different processing parameters by mechanical property evaluation.