A solder joint inspection system for surface mounted pin grid arrays

Abstract

A solder joint visual inspection system for surface mounted pin grid arrays has been developed. An XYZ-robot controls the optical fiber scope (OFS), 0.9 mm in diameter, and obtains an OFS image of the inspected solder joints. A virtual data fuzzy clustering algorithm has also been developed for extracting, from the OFS image, the data regarding joint locations, and the data are then used in defect detection. In an experiment carried out on 7104 solder joints, of which 4 were defective, the system successfully detected all the 4 defects, while the number of "good joints" mistakenly identified as being defective was only 0.8% of the total.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>