Good Solder Joint Failures

2017/2/2 5:32:53

Hope some of you out there can help me with this one. I am getting feedback from our test department that they are showing opens on solder joints which have visually good wetting. The touch-up operators confirm that the joint looks good. All they do is go over the joint(s) with an iron and it passes test. The frequency of this issue is very low (though no ppm data is available at this time) but it is enough for concern. There seems to be no pattern to location, part type or board. We use primarily no-clean solder paste. I have asked for samples from future occurances. These will be viewed with higher power scopes and x-rayed. Any comments are appreciated.