Hello, I am having a problem with HASL PCB's after it comes back from the stuffer. To me it looks like oxidation and it causes poor wetting. This leads to a bunch of problems all of which have different symptoms but the cause is this oxidation problem.
I spent considerable effort in trying to find the cause and I have eliminated the PCBA stuffer as the cause. I suspect this is a PCB vendor issue. I asked around my building and someone commented that it could be the quality of the copper trace. I'm thinking it might be the quality of the solder used in the HASL process.... but I do not know.
What do you guys think? I'm about to contact the PCB maker but I am oblivious as to what they may be doing wrong. Note that this problem is a recent problem. We never had this problem before. The PCBA stuffer did not change their process and we tested older boards from the PCB maker and it doesnt have this problem, only the latest boards from them do this....
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