The Torsional Characterization of 3D-Printed Polylactic Acid Parts With Alternating Additive Manufacturing Parameters

Three-dimensional (3D) printed polymer parts can be subjected to torsional loads in accordance with the conditions of use. Understanding the torsional properties of 3D printed polymers depending on the printing parameters is a significant research topic in fused deposition modeling (FDM) additive manufacturing processes to be used as machine parts operating under torsional load, such as polymer parts manufactured by extrusion method. Some studies have shown that raster angle and printing speed affect the mechanical properties of 3D-printed polymers. However, tensile tests were used in most of those studies. In this study, the torsional behavior of 3D printed Polylactic acid (PLA) materials was investigated by static torsion tests, finite element analyses, and theoretical and failure analyses with respect to the printing speed and raster angle parameters. Torsion test specimens were manufactured at five different raster angles (0 degrees, 30 degrees, 45 degrees, 60 degrees, and 90 degrees) and two different printing speeds (20 and 80 mm/s) from PLA material using the FDM additive manufacturing method. The results showed that raster angle and printing speed parameters affected the torsional load-carrying capacity of FDM-3D printed PLA parts. The best load-carrying capacity was achieved at 30 degrees and 60 degrees raster angles, while the lowest was measured at 0 degrees raster angle. The torsional load-carrying capacity was significantly enhanced by 85% for specimens manufactured at the printing speed of 80 mm/s.