Medical inspection technology brings industrial benefits

Incorporating technology that has been proven in medicine for over 40 years into the industrial arena, the new speed|scan atlineCT system comes from the Inspection Technologies business of GE Measurement & Control. High-speed CT is the only method currently available that allows internal structures of extremely complex components made of cast alloys, (such as wall thicknesses in cylinder heads), to be inspected on a non-destructive basis directly on or near the production line. The system uses Helix multi-line technology, where a gantry with an X-ray tube and corresponding multi-line X-ray detector rotates around the workpiece, which is being passed through the gantry on a conveyor belt. The workpieces are scanned at speeds of up to several millimetres per second and are automatically assessed with the aid of GE's own speed-optimised 3D Automatic Defect Recognition (ADR) algorithms. Although used in medicine for many years now, CT inspection has only developed into a reliable method for scientific and industrial inspection over the last few years. This technology makes it possible to carry out one hundred percent 3D inspections for a very wide range of industrial applications, even at high throughput rates. The typical throughput requirements for the foundry industry extend from 10 seconds for small pistons or chassis components to as much as 80-90 seconds for complex engine components, such as cylinder heads. A fully automatic inspection method, including the whole data acquisition and analysis process, is required to meet these cycle times. In addition to increased speed, there are benefits such as a reduction in reject rate by analysing position and form of defects that may be machined out by subsequent processes to prevent unnecessary failures occuring and by accurately checking workpiece geometry and dimensions, meaning that form and size deviations can be easily identified and corrected at an early stage of the production process. Finally, depending on their size and absorption behaviour, even foreign materials like inclusions or sand core remains may be detected, located and classified according to density and position. Moreover, to avoid waste, it is possible to check whether identified porous areas will be open on the final surface before processing begins. At the same time, the scanned workpiece geometry can be checked for anomalies using the nominal CAD data. While the concept for the fast industrial inline CT system is based on medical tomography systems from GE Healthcare, a number of adaptations have had to take place to transfer this technology from one arena to the other. For this reason, the scanners have been given appropriate transport facilities and automated 3D failure evaluation software modules for continuous operation in high-speed industrial inspection systems. In addition, a specially-developed, air-conditioned safety cabinet not only protects the surrounding area from the X-ray radiation, but also protects the tomograph from the dust and heat generated in harsh production environments.