Using X-ray computed tomography to improve the porosity level of polyamide-12 laser sintered parts

Porosity is a key parameter determining the functional application limits of polymeric parts produced by laser sintering (LS). In this paper, X-ray computed tomography (CT) is used to investigate the influence of the LS scanning parameters (laser power, hatch spacing, and scan speed) and part or feature size on the distribution and size of pores within polyamide-12 (PA12) laser sintered parts. CT model slices are created parallel to the original LS manufacturing layers in order to determine the porosity distribution and variation within each layer as well as along subsequent layers. Mapping the porosity distribution within these slices onto the laser scanning trajectory moreover allows investigating the influence of LS scanning parameters. Correlation of these porosity data with results from mechanical testing allows identifying optimal LS scanning parameters.