Herminso Villarraga-Gómez, X-ray CT Metrology Specialist, Nikon Metrology Inc
Additive Manufacturing (AM)-based precision engineering devices and components that have complex shapes can be easily designed and manufactured at a relatively low cost. However, many questions about structural integrity, tolerance limits, and material characterization remain unanswered because such devices are in general three-dimensional, complex, hollow inside, and often made from soft viscoelastic materials. In this presentation, we will discusses methods for the assessment of structural integrity and dimensional measurements of the internal geometries produced by additive manufacturing (AM) processes. Computed Tomography (CT) shows promise as a non-destructive method for acquiring the dimensional characterization of both internal and external geometries of AM parts, and it might be the only available option to extract component dimensions of internal or hidden structures in an assembled product. This makes the CT technology particularly useful to study AM parts for inspection, material quality control, process studies, and dimensional metrology. Currently, from the measurements of actual to nominal comparison, typical variations in dimensional geometry of AM parts with respect to reference geometry (nominal data), are around ±50 m to ±100 m. In general, the X-Ray CT technique provided not only visual inspection, but also quantitative and qualitative control tools to assess completeness of AM terminated products.