Any company using advanced X-ray technologies to look inside components for, say, casting faults in cylinder heads and engine blocks is working at the leading edge of technology.
Now a team of engineers in Germany has taken magnetic resonance (MR) imagery - or computer tomography - a significant stage further. They have discovered how to adapt and use the equipment not only to see but also to measure the inner structures scanned components.

This breakthrough allows manufactured or prototype components to be directly compared with computer models and can be used in studies as new products are being developed . A competitive product, for example, can be scanned in precise detail - internally and externally - and given back to the research and development team as CAD data.
Engineers can also investigate internal workings of a component. And of course, it is the ultimate quality control tool, allowing actual components to be dimensionally compared, externally and internally, with the CEA models from which the tooling was made.

Behind the development is a team from Delphi's Customer Technology Centre in Wuppertal led by Peter Knauff, project manager of the Continuous Improvement Group.
Like so many good ideas, the new machine resulted from the engineer's insatiable desire for complete understanding , in this case when Knauff found himself needing an MR scan for medical reasons a few years ago. He questioned the radiologists about its capabilities and potential and then, with his Wuppertal team, set to work with the equipment manufacturers, Xylon International of Hamburg, on an industrial machine that would add that crucial third dimension - precision measurement. Now Delphi is working with Bergisch Gladbach University in Wuppertal to explore and investigate further opportunities for industrial applications.

Compared with equipment used in medical computer tomography, the substantial difference is that the machine remains motionless while the object being analysed is rotated. However, it is also built along the lines of a coordinate measurement machine (CMM) with a massive 6 tonne granite table - largely isolated from its environmental influencesand ensures the precision of movements between the individual system axes. The whole machine is encased in 8 to 12 mm thick lead weighing more than 10 tonnes with the access door on its own weighing 400 kg.

The computer tomograph has four basic elements: an X-ray source, the specimen stand, detector and manipulator. The component being examined is mounted on the stand and precisely positition between the X-ray source and detector. Source energy levels are set to provide the ideal level of penetration for the component's material. The stand is then rotated through 360° over +/- 20 min during which time 1440 images are taken of the part.

European Automotive Design, February 2007

1) Search the Internet for an explanation of MR. See for instonce http://en.wikipedia.org/wiki/Computed_tomography

2) What is computer tomography used for in health and accident diagnosis? Have you ever been in a tomograph?

3) What are the benefits of scanning mechanical structures?

4) Components made from many different materials can be examined simply by adjusting the X-ray source energy level. For practical purposes 6 mm steel is thought of as being the threshold.
Why?