Effect of Process Parameters and Postprocessing on Mechanical Properties of Additive Manufacturing Polylactic Acid Obtained by Fused Deposition Modeling

The aim of this article is to study the influence of some printing parameters and postprocessing on mechanical properties of polylactic acid samples manufactured by fused deposition modeling with a 3D printer. The effects of different building orientations, concentric infill, and postprocessing by annealing were analyzed. In this sense, uniaxial tensile and three-point bending tests were performed to determine the ultimate strength, modulus of elasticity, and elongation at break. Among all printing parameters of interest, the print orientation can be considered one of the most important, being fundamental in the mechanical behavior. Once samples were fabricated, annealing processes were also considered, close to the T-g, in order to study the effects on mechanical properties. In the modified print orientation, the average values for the E and the sigma(TS) are 3337.15-3337.92 and 36.42-37.62 MPa, compared with default printing with the E and the sigma(TS) that are 2541.63-2692.34 and 28.81-28.89 MPa, respectively. In the annealed samples, the values for the E-f and the sigma(f) are 2337.73 and 63.96 MPa, compared with the reference samples with the E-f and the sigma(f) values of 2164.40 and 59.66 MPa, respectively. Hence, the print orientation and postprocessing must be taken into account as important factors for the final properties of the desired product.