Impact of 3D printing parameters on static and fatigue properties of polylactic acid (PLA) bone scaffolds

In the present study, polylactic acid (PLA) scaffolds with a 60 % porosity and gyroid pore structure were 3D printed using the extrusion-based method and employing various printing parameters. The specimens were loaded under quasit-static and cyclic conditions and their mechanical behaviour were evaluated. The Taguchi method was utilized to design experiments and investigate the impact of printing parameters on the compressive properties of the scaffolds. Moreover, thermography analysis was used to examine the influence of cyclic heating during fatigue experiments. The results indicated that extrusion width was the sole variable significantly affecting the quasi-static properties of scaffolds. The largest extrusion width (0.65 mm) resulted in the highest compressive properties (6–7 MPa), plateau stress (8–9 MPa), and compressive modulus (200–215 MPa). However, fatigue experiments revealed that nozzle temperature was the sole influencing factor on the fatigue performance of scaffolds, with specimens printed at low nozzle temperature (190 °C) demonstrating the highest fatigue resistance. Thermography analysis exhibited a negative correlation between scaffold temperature and stiffness. However, the impact of temperature on the structural integrity of the scaffolds was insignificant, given that the highest temperature recorded during fatigue cycles (i.e., 39 °C) was below the glass transition temperature of the scaffolds’ material.