A comprehensive study of tensile properties of 3D-printed polylactic acid (PLA) parts based on statistical analysis and multi-response optimization of printing parameters

This study presents a comprehensive investigation of all the key tensile properties of 3D-printed polylactic acid (PLA) parts, including tensile strength, yield strength, modulus of elasticity, elongation at break, and energy at break. A three-factor, two-level (2 ³ ) full factorial design of experiments (DOE) was employed to analyze the main and interaction effects of layer thickness, printing angle, and printing speed. Statistical analysis reveals that layer thickness significantly affects all tensile properties except ductility, with increased layer thickness generally reducing strength, stiffness, ductility and toughness. Printing angle and speed show minimal influences on the tensile properties but with consistent trends. A significant interaction is observed between layer thickness and printing angle, specifically on ductility and toughness. Multi-response optimizations are conducted to identify optimal printing parameters for maximizing strength, ductility, and balanced strength and ductility, respectively. For maximizing strength and stiffness, the optimal settings are low layer thickness (0.25 mm), high printing angle (60°), and high printing speed (60 mm/s). To maximize ductility and toughness, the optimal settings are low layer thickness (0.25 mm), low printing angle (45°), and high printing speed (60 mm/s), which also provide the most balanced combination of strength and ductility for the 3D-printed PLA parts. The findings offer valuable guidance for tailoring FDM parameters to achieve desired mechanical behaviors in 3D-printed PLA components based on their applications.