Industrial X-ray computed tomography

Industrial computed tomography is considered the third revolution of dimensional measurements. The first revolution was the development of coordinate measuring machines and the second optical 3D measuring devices such as laser trackers. Industrial X-ray computed tomography (XCT) utilizes the same technology as hospital equipment. However, the method, the operating parameters and the analysis of the results are tuned for the needs of industrial workpiece measurements. The advantage of XCT measurements over probing coordinate measurements is that a single measurement, where the intensity passing through the sample is measured in several different positions of the sample, gives a volumetric image of the sample after reconstruction. After defining the surfaces, the dimensions and shapes can be measured from the 3D image using metrology software. The reliability of the results requires that the measurement is traceable. 
 

VTT MIKES offers traceable XCT measurements XCT1.jpg


Properties of XCT measurements compared to traditional coordinate measurements

advantages:

  • holistic image of the sample in a single measurement
  • distinguishes between internal structures and various components and materials 
  • programming of measurements is straightforward
  • total measurement time is short 

disadvantages:

  • the resolution is limited by the number of pixels in the cell,
    e.g. resolution = sample size / pixel size
  • X-ray permeability is only a few centimetres in dense substances

 
VTT MIKES has access to a modern industrial X-ray tomography device GE phoenix v|tome|x s 240.

Main properties of the XCT device.  

Property Spesification
ModelGE phoenix v|tome|x s 240
Sample size
    – diameter
    – height
 
0.1…240 mm 
420 mm
Detector: GE DXR250
    – size
    – pixels

410 mm × 410 mm
2048 × 2048
X-ray tube tube: Microfocus  xs|240d
    – ​accelerationg voltage / power
    – min. resolution
  
240kV / 320W 
5 µm
X-ray tube: Nanofocus  xs|180nf
    – accelerationg voltage / power
    – min. resolution
 
180kV / 20W
0.9 µm

 

The XCT measuring procedure is the following:

  1. planning the measurement
  2. creating traceability
  3. XCT measurement of the sample
  4. reconstructing a 3D model
  5. defining the sample surface
  6. dimensional analysis and uncertainty evaluation

xCT2.jpg    xCT3.jpg

​Cross-sectional XCT image of a fuel nozzle and a tip of a hypodermic needle.
 

Contact 

  • Antti Lassila, Research Team Leader, tel. +358 40 767 8584, email antti.lassila(at)vtt.fi
  • Ville Heikkinen, Research Scientist, tel. +358 50 415 5980, email ville.heikkinen(at)vtt.fi


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