Circuit board assembly inspection

摘要

Circuit board assemblies 6 consisting of printed circuit boards 7 to which surface mounted components 8 have been mounted are visually inspected by comparison with a reference circuit board assembly. A reference image is visually compared with a test image using the display of a personal computer. Image data is acquired in each case by use of an optical scanner 2 in the form of a flatbed scanner. The circuit board assemblies are positioned during scanning so as to locate a major surface of the circuit board and the surface mounted components within an imaging region 44 of the scanner. Alignment of images is automatically effected by the computer so as to display images using a common frame of reference defined relative to fiducial features of the circuit board assemblies. During scanning, the boards may be supported in an upwardly facing or inverted position within a light excluding enclosure. The method has application to small and medium scale production facilities of printed circuit board assemblies.