The mechanical properties of aged PA-12 FS3300PA powder: influence of layer thickness, sintering orientations, and laser power

Abstract This research investigates the influence of layer thickness, laser power, and sintering orientation on the mechanical properties of aged Polyamide-12 (PA-12) FS3300PA using the Selective Laser Sintering (SLS) 3D printing method. Specimens were sintered with three different layer thicknesses, laser powers, and sintering orientations using SLS. The study also aimed to examine the resulting powder morphology, mechanical properties, and tensile fracture behaviors of the aged (more than eight continuously sintering cycles) and virgin FS3300PA powders. The specimens divided into ten groups: nine groups of aged powder and one group of virgin powder as a benchmark. The nine groups of aged powder were sintered with three different layer thicknesses (0.07 mm, 0.12 mm, and 0.15 mm), laser powers (65 W, 70 W, and 75 W), and orientations (YZY 0°, YZY 90°, and XYY 0°). The selections of these laser power and layer thickness values for the sintering setting are due to machine and material parameter limitation. The results from these parameters then compared with those of the virgin powder, which sintered using the parameters provided by the manufacturer, in terms of powder morphology, mechanical properties, and tensile fracture behaviours. Observation made using scanning electron microscope (SEM) revealed that there were not many changes in shape, size, and distribution between the virgin and aged powder, but slightly larger sizes and the presence of cracks found in the aged powder. The tensile strength, elongation at break value, and Young’s modulus all shared a similar trend, increasing with higher laser power but decreasing with increased layer thickness. Regarding the fracture morphologies, the number of pores and dimples decreased with increased laser power but increased with thicker layer thickness. There was also the occurrence of un-molten powder, especially in specimens sintered at the YZY 90° orientation with lower laser power and thicker layer thickness.