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Automated 3D X-ray inspection of fine pitch PCB's

: Hanke, R.F.; Weiss, T.; Petsch, N.


Lau, J. ; Institute of Electrical and Electronics Engineers -IEEE-:
Integrated Manufacturing: the future is now. Thirteenth IEEE/CHMT International Electronics Manufacturing Technology Symposium
Piscataway, NJ: IEEE, 1992
ISBN: 0-7803-0755-0
ISBN: 0-7803-0756-9
ISBN: 0-7803-0757-7
International Electronics Manufacturing Technology Symposium (IEMT) <13, 1992, Baltimore/Md.>
Conference Paper
Fraunhofer IIS A ( IIS) ()
Qualitätssicherung; quality control; Röntgenbildverarbeitung; Röntgenprüfung; x-ray image processing system; x-ray inspection

The recently developed x-ray system 3D-DELTA (3-dim. Defect Localization and depht Analysis) for automatic PCB testing is presented. The system was developed for faster spatial data extraction by use of only two x-ray images of the PCBs. The result is the 3-dimensional classification of defects within solder joints and of the solder joints itself without the use of complex computer tomographic algorithms. First, the x-ray imaging system for data acquisition is shown. In order to achieve the required data for evaluation, two micro focus x-ray sources are used to produce a stereo image pair during one scan. The use of a line scanning x-ray detector allows the image acquisition line by line with contrast enhancement during object movement. Time loss by stop and go of the assembly line is avoided with this method. Second, the data preparation by matching and subsequent division of an adapted reference image form the x-ray data is described. Finally, the algorithm for testing the solder joi nts for completeness and faint flaws is outlined. A combination between absolute thickn ess measurement by evaluation of polychromatic intensity distribution of the solder pads and 3D-localization by stereoscopic technics is presented.