German engineers have developed an advanced industrial X-ray system for checking the dimensions of machined components.
The system — designed at the Fraunhofer Development Centre for X-ray technology near Nuremberg — uses a computed tomography (CT) scanner developed by German company ProCon X-Ray, which is marketing the device in mainland Europe.
Specially-designed software by Fraunhofer engineers builds up highly accurate 3D X-ray images of a scanned component.
Manufacturers traditionally use either destructive methods or optical or surface scanning techniques to check components, which as well as taking several hours also makes it difficult to inspect complex contours.
The new device scans an object by registering the transition from solid body to air. This enables it to determine the contours of the component and therefore its actual measurements. The software then converts these measurements into a 3D cloud of measuring points, and a specially developed algorithm identifies geometrical forms such as planes and cylinders.
The 3D X-ray image, said to be accurate to within 10 micrometers, can then be compared with the original CAD model of the object to check that the finished component matches the original design.
Randolf Hanke, head of Fraunhofer’s X-ray centre, said: ‘The test design has for the first time enabled us to complete the process chain from a CAD model to the production of a sample and back to a CAD model again.’
Joachim Gudat, managing director of ProCon X-Ray, said that one of the technology’s chief advantages is the introduction of a new detector system that enables the device to scan far larger specimens than previously possible. This, he claimed, makes it competitive with larger, more expensive industrial X-ray machines.
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In the UK, the system is being marketed by West Sussex-based testing specialist Systegration. Managing director Alastair Sharp said that he is currently discussing applications for the system in fields from paleantology through to fuel injection. He claimed that the technology represents one of the only non-destructive methods of looking inside components.
Sharp explained that the problem with conventional X-ray systems is that, because they rely on a 2D shadowing technique, much of the important 3D information is invisible to the operator. The beauty of the new system, he said, is that information is taken from up to 800 different directions around the sample.
The reconstruction algorithm then enables the user to view the relevant section of the component. German automotive supplier ITW Deltar is already using the system for sampling injection-moulded cogwheels used in seatbelt systems. Quality manager Ralf Wulf said it should halve the time spent on measurement.