The detection of imperfections (such as disconnections, chipping cracks, nonuniformity in thickness and short-circuit, etc.) on the traces of bare printed circuit board (PCB) using a new high-sensitive eddy-current testing (ECT) probe has been reported in this paper. The ECT technique is composed of planar meander type exciting coil and a new multiple solenoid sensing coil. The image processing method is used to analyze the results. This paper has discussed the structure of the new probe, the characteristics of the measurement technique to inspect high-density PCB with narrow conductor-width. And the possibility of detecting micro-metal ball has been explored.
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