Utilising Computed Tomography as NDT Technique in Additive Manufacturing

Alderton, Stephen,; GE Sensing & Inspection Technologies GmbH; Germany

Alderton, S.; GE Digital Solutions - Inspection Technologies; United Kingdom
Luebbehuesen, J.; GE Sensing & Inspection Technologies GmbH; Germany

ID: ECNDT-0417-2018
Session: Additive Manufacturing – radiographic methods
Room: H1
Date: 2018-06-11
Time: 13:50 - 14:10

Additive Manufacturing (AM) is presently revolutionising industrial production in many sectors (Aerospace, Automotive, PowerGen, Oil&Gas, Medical, etc.) and is expected to substantially substitute traditional moulding and casting processes within the next decade to come. For many workpieces made of plastic and metal based materials, AM tends to be the more convenient manufacturing technique due to their complexity and geometry.

Apart from other known non-destructive techniques to assure quality of AM products such as e.g. in-situ monitoring during the build process, computed tomography (CT) turns out to be one of the most efficient NDT methods. Not only does CT enable the three-dimensional volumetric visualization of indications and internal geometries that traditional NDT methods can scarcely or not access, it also allows to be used for metrology application tasks, such as dimensional measurement of interior and exterior features, variance analyses (CAD data, part-to-part) and pre-machining workpiece control.

Moreover, CT may help analyse the granulometry, topology and sphericity of AM powder particles (new/recycled) to assure quality of the incoming material prior to the printing process.

In view of new types of defects and flaws to be detected in AM parts, CT can meet requirements for increased resolution, higher penetrability and X-ray scatter-corrected volume data sets of workpieces made of dense materials (e.g. Inconel, CoCr, etc.) allowing for reliable and reproducible measurement results. Thanks to this and to improved automatic workflows, CT continues its move from being a traditional expert R&D device towards the use as an automatic measurement technique on or close to the production floor.

Computed tomography can help to set standards for quality assurance of AM parts. Hence, standardisation organisations such as ISO and ASTM rely on the recommendations and the expertise of CT system suppliers and CT users among the AM community members.