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Automated Optical Inspection (AOI/AXI)
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Basic Principles of X-Ray Inspection - AXI

Basic principle of Automated X-Ray inspection

3D X-Ray Inspection

X-ray inspection (3D) - different projections of a double-sided assembled PCB
X-ray inspection (3D) - different projections of a double-sided assembled PCB

A PCB is selectively radiated from different angles. Enabling the reconstruction of single layer as required.

Operational Fields

  • In-line 3D X-ray inspection
  • Inspection of double-sided assembled PCBs
  • Qualitative inspection of all solder joints (e.g. BGA, QFN)
  • Check for presence, mismatch and shorts
  • Void measurement in various layers
  • Inspection of complex PCBs with overlaid solder levels and mounted cooling devices
  • Determination of capillary action in THT solder joints

Advantages of 3D X-Ray Inspection

  • Safe inspection of double-sided assembled PCBs
  • Reconstruction of any layers
  • Fast and user friendly test program generation by using a single unified library

Revolutionary Image Capturing Concept enables practical in-line 3D X-ray inspection.

At present, only a minority of 3D AXI systems are fast enough to enable a complete PCB inspection within the production cycle. As a matter of principle, a 3D reconstruction of a PCB requires a high number of angled radiations. Normally, the corresponding multitude of image capturing and large amounts of data, dramatically limits inspection speed. Not so when GOEPEL electronic’s X-ray inspection system OptiCon X-Line 3D is utilized. The revolution-ary GigaPixel technology enables a complete 3D x-ray inspection of the entire PCB at speeds of up to 40cm²/s.

What is behind the GigaPixel Technology?

This technology’s core element is a fast and highly sensitive detector module enabling a si-multaneous capture of images from various directions.

The 3D x-ray detector works based on an image intensifier, allowing image capturing from nine different directions at 12 bit grey value range and object resolution of maximum 6.3 µm per pixel. The detector hardware reaches a constant data rate of up to 40 GigaPixel per second. Time neutral image integration and pre-processing is implemented by integrated computational hardware. Allocated to the nine view directions, the resulting 360 MegaPixel per second data rate is made available for further processing in the PC after hardware based image integration and pre-processing. In a reconstruction procedure these image data streams are transferred to a theoretical 3D area giving performance of up to 48 MegaPixel per second. GOEPEL electronic is able to control this large amount of data by means of parallization and utilisation of the latest hardware technologies.

The result is very impressive: 100% in-line 3D X-ray inspection at up to 40 cm²/s.

3D X-Ray Inspection with OptiCon X-Line 3D offered by GÖPEL electronic.

2,5D X-Ray Inspection

X-ray inspection (2.5D) - Optically separated solder joints in off-axis view
X-ray inspection (2.5D) - Optically separated solder joints in off-axis view

Overlaid solder joints (e.g. on top and bottom side of PCB) are optically separated by off-axis view in the projections.

Disadvantages of 2,5D X-Ray Inspection

  • Very high programming effort for double-sided assembled PCBs by manual parameterisation of single image capturing
  • No unified library usable
  • Long test times

2D X-Ray Inspection

X-ray inspection (2D) - overlaid solder joint in orthogonal radiography
X-ray inspection (2D) - overlaid solder joint in orthogonal radiography

PCBs are radiated orthogonally

Disadvantages of 2D X-Ray Inspection

  • Overlaid solder joints (e.g. at double-sided assembly) cannot be inspected
  • Unsatisfactory statement about BGA solder joints
  • No spatial allocation of faults
Andreas  Tuerk - GOEPEL electronics

Andreas Tuerk

+49 3641 6896 895