Evaluation of Tensile Stress Relaxation of Selective Laser Sintering of PA2200 Material using the Maxwell-Wiechert Model

The use of 3D printing for the manufacture of functional components has led to a demand for research into the mechanical properties, including rheological properties, of additive manufactured models. In this article, the results of a study to evaluate the relaxation of tensile stress of samples made by selective laser sintering (SLS) of PA2200 material are presented. The evaluation of tensile stress relaxation was performed using the five-parameter Maxwell-Wiechert model. With the model used, elastic moduli and dynamic viscosity coefficients were calculated. The samples were made in three print orientations (0°, 45°, 90°) and two types of energy density (E_d = 0.056 J/mm², E_d = 0.076 J/mm²). The results indicate that increasing the applied energy density leads to higher values of elastic moduli and dynamic viscosity coefficients. A strong fit of the model to the experimental curves was obtained, as confirmed by the obtained coefficients Chi² and R². This research comprehensively addresses the evaluation of the applicability of selective laser sintering technology, which is increasingly used in various areas of industry, as well as the influence of the process on the relaxation of tensile stress.