Physics and technology of fully automated industrial 3D-CT inspection in production

Speaker:
Gondrom-Linke, Sven; Volume Graphics GmbH; Germany

Authors:
Gondrom-Linke, S.; Volume Graphics GmbH; Germany

ID: ECNDT-0373-2018
Download: PDF
Session: CT-Applications 4
Room: G3
Date: 2018-06-13
Time: 16:20 - 16:40

3D computed tomography has evolved so rapidly in recent years and made such progress in acceptance and distribution, that it is now considered to be a standard procedure not only in laboratories but as well in production environments.
The benefits of 3D-CT compared with long-established 2D X-ray methods are obvious. 3D-CT provides much more information than conventional 2D methods. It allows an easier detection of defects and internal structures than 2D methods and delivers as well information about their exact location, size, and shape. Furthermore, 3D-CT can determine the wall thickness of components and do nominal/actual comparisons using CAD data.
This wide range of application possibilities predestines 3D-CT as an universal, non-destructive inspection method whose advantages nowadays is transferred to production.
However, it has to be noted that boundary conditions in a production environment differ quite immensely from those in the lab. Very fast cycle times down to 15s to 30s lead to dramatically reduced numbers of detected X-ray photons, compared to a standard CT. This explains the necessity to recall and check again the basic physical relations between photon statistics, SNR, contrast, geometrical resolution, cycle time, and last not least facility costs, in order to optimize in-line 3D-CT setups. Specially adapted HW, as well as SW solutions are required to perform fast and meaningful analyses and measurements.
This paper describes the relevant physical parameters for CT measurement and the effect a short measurement time has on the measurement and feature extraction of the components being tested. We not only discuss this in theory, but will share the experience from several successful inline CT installations, e.g. in automotive industry.