Solder contamination
The solder in the solder baths of wave soldering and selective soldering systems contaminates over time. When the liquid solder contacts the printed circuit board, metallization’s on the board dissolve and other contamination found on the board get washed off by the solder wave, ending up in the solder bath. In the worst case, these contaminations may change the characteristics of the solder and impact on the reliability of the solder joints.