High-resolution microfocus X-ray computed tomography for 3D surface roughness measurements of additive manufactured porous materials

Since commercially available profiling systems fail when determining the surface roughness of porous materials, we propose a novel protocol for surface roughness quantification of 3D additive manufactured porous structures based on high-resolution microfocus X-ray computed tomography (micro-CT) images. It allows to non-destructively assess the roughness of these porous materials at the outer surface as well as inside the structure. The noise in the images and the spatial image resolution both have a significant effect on the accuracy of the micro-CT-based roughness measurements. Comparing the roughness parameters of flat substrates determined both with commercially available (optical and contact) profiling systems and the micro-CT-based roughness measurement protocol shows that micro-CT can be applied accurately and in a robust manner for surface roughness quantification of 3D additive manufactured porous materials with a micro-scale roughness. Depending on the dimensions of the roughness, the micro-CT acquisition parameters, i.e., frame averaging and spatial image resolution, need to be fine-tuned. Submicron-scale roughness can currently not be quantified.