A new approach for measuring the wetting angles of lead-free solder alloys from digital images

Abstract

This study aims to detect quaternary lead-free solder alloys and measure their dynamic wetting angles with a new approach. The detection of the prepared alloy drop and measurement of its wetting angle are automatically performed by the developed application. A video obtained after experimental studies is filtered over its frames and enhanced a better form in the preprocessing stage. The peak of the half alloy drop is detected by obtaining lane histogram and its global minimum point is found in the segmentation stage. Left and right corner points in contact with the ground are detected by tracking pixel intensity values with the help of the global minimum point. The median point for both left half alloy drop and right half alloy drop is calculated. Thus, circles passing through three points for the left half and right half of the alloy drop are obtained to measure θleft,θrightandθmean wetting angles. In the postprocessing stage, these angles are measured at 0th, 5th, 10th, 15th, 30th, 60th, 90th, 120th, 150th, and 300th seconds after the alloy drop contacted the ground. Besides, measurement of these wetting angles is performed at each second. The obtained results showed that the graph of θmean versus time is an exponential decay graph. This result proves that the alloy drop spreads over the ground as time passes and the value of θmean decreases and is consistent with the observation made during the experiment.