Tehnički Vjesnik (Jan 2020)
Rheological Properties of Polyamide PA 2200 in SLS Technology
Abstract
Mechanical properties, accuracy and tribological properties of additively manufactured models depend on the technological parameters. In the presented work, models made in selective laser sintering technology with modified technological parameters were analyzed.Therefore, the presented research attempts to determine the influence of two technological parameters (layer thickness in the 0.1 - 0.4 mm range and the printing direction (0° and 90°)) on stress relaxation determined during the uniaxial compression test (testing machine-Inspekt 3 kN) and on the mass of models (density of model material) manufactured by SLS technology with PA 2200 polyamide powder. Using the Origin software and the five-parameter rheological model of the so-called "Maxwell-Wiechert model", the rheological models of the samples were approximated, which allowed for the assessment of the possibility of adapting this rheological model for further investigations of additively produced models using SLS technology. The test results showed a clear effect of the layer thickness, both on the stress relaxation and on the mass of the produced models. In addition, it has been shown that the printing direction affects stress relaxation, however, it has no direct effect on the mass (density of the material) of the models. The variant PD = 0° is the most favourable for enabling the production of models with the highest strength, and for the production of reduced weight models.
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