3D-Printed PLA Mechanical and Viscoelastic Behavior Dependence on the Nozzle Temperature and Printing Orientation

The present study focuses on the mechanical and viscoelastic characterization of 3D-printed PLA, fabricated in three different printing orientations (0°, 45°, and 90°) and four different nozzle temperatures (210, 220, 230, and 240 °C). By employing a combination of static and dynamic mechanical analysis (DMA) testing, as well as differential scanning calorimetry (DSC) analysis, this work aims to investigate the relationship between processing parameters and the resulting properties of PLA. DSC results showed that higher nozzle temperatures enhance the degree of crystallinity, which in turn affects the mechanical and viscoelastic behavior of PLA. Regardless of the nozzle temperature, the flexural strength decreased as the printing orientation degrees increased. However, it was found that the higher the nozzle temperature, the higher the flexural strength for the same orientation, and the smaller the strength deviations per specimen. DMA results indicated that as the printing orientation increased, glass transition temperature (T_g) values increased while storage modulus values decreased. At the same time, in both cases, by increasing nozzle temperature, an increase in T_g and a respective increase in storage modulus values is observed due to the increase in the degree of crystallinity.