Author:

Keywords:

Selective Laser Sintering (SLS), X-Ray Computed Tomography, Quality control, porosity measurement, Crystallinity, Mechanical Properties, Science & Technology, Technology, Engineering, Biomedical, Engineering, Manufacturing, Engineering, X-ray Computed Tomography, Laser Sintering, Porosity Analysis, Non-Destructive Testing, PA12, Differential Scanning Calorimetry, POLYAMIDES

Abstract:

Laser Sintering is an Additive Manufacturing technique increasingly used to produce functional parts, with polyamide-12 (PA12) being by far the most processed material. It is common practice in industry to process a mix of recycled and virgin PA12 powder; however it is not yet fully understood how the Laser Sintering process parameters influence the microstructural composition for this mixture, namely the degree of crystallinity, the porosity characteristics and the distribution of the pores within the sintered parts. In this work X-ray Computed Tomography (CT) is used to investigate the porosity of tensile bars printed flatwise with different Laser Sintering process energy densities. Analysis of the pores characteristics and image processing of the CT-slices parallel to the building platform provide insights into the link between Laser Sintering process parameters, pores formation and their arrangement into the sintered polymer for different energy density levels. This information combined with the crystallinity values measured by Differential Scanning Calorimetry, gives a complete picture of the microstructure of the sintered material and its link with the resulting tensile properties.