Thermal Model of the Build Environment for Polyamide Powder Selective Laser Sintering

Precise thermal control of selective laser sintering (SLS) is desirable for improving geometric accuracy, mechanical properties, and surface finish of nylon, or polyamide (PA) parts. A modeling and measurement system was set up to facilitate development of thermal control strategies to improve these characteristics. A SinterStation 2500 SLS machine was used as a test machine for studying builds of parts made of DuraformTM PM nylon powder. Internal temperature measurements of the process were made using resistance temperature detectors (RTDs) embedded in the part bed powder. Surface temperature was measured with an infra-red camera aimed through the front window. A macro-scale time-dependent thermal numerical model of the build chamber and powder bins was developed as a means of evaluating temperature control of the build process. By comparing the measured and predicted temperature profiles, various estimates of the thermal diffusivity of the nylon powder were evaluated.Mechanical Engineerin