Effect of selective enhancement on the bending performance of fused deposition methods 3D-printed PLA models

The top and bottom shells of fused deposition 3D-printed PLA models are exposed to the highest stresses. To improve the bending performance of PLA models under three-point bending conditions, the models were strengthened by a selective enhancement method. Several sets of PLA models were fabricated using FDM technology, and three-point bending experiments were conducted to compare the bending strength of PLA models when the layer height, top/bottom shell thickness, and extrusion rate were varied. The bending strength of the PLA models increased as the layer height of the top/bottom shell decreased, the thickness increased, and the extrusion rate increased. The average bending strength of the PLA models after selective enhancement was 84.4 MPa, and the average bending modulus of elasticity was 0.816 GPa, which were higher than the average bending strength of 68.6 MPa and the average bending modulus of elasticity of 0.736 GPa of the conventional groups. These results indicated that the selective enhancement method improved the bending performance of 3D-printed PLA models, and it also provided a reference for the improvement of the mechanical properties of the 3D-printed models with cellulose composite reinforced materials.