Heck, now I look up and see this is SMTdotNET. Do I get banned for asking a TH question?
So here's my first real TH issue after living so long in the SMT world.
We are having a sudden issue in what has been a stable process for quite some time. It appears to be confined to a particular lot of PCBs. Finish is ENIG. Solder is good old SN63/Pb37, flux is DI water washable. PCBs are baked for 24 hours before SMT processes, and all soldering processes are completed within 48 hours.
After the selective soldering process we are suddenly experiencing what I would call a de-wetting issue in the barrels of a particular high pin count connector. Same connector location, but random barrels.
We are required to inspect the barrels by X-Ray for correct fill, and we see 100% fill for a year now, and then suddenly this random lack of fill, although the solder is reaching the topside of the PCB, which we can visually observe.
Again, a mature process, all maintenance on the machine is up to date, and the solder maintenance is up to date and within spec as well. I am thinking some kind of contamination.
Can some folks from this enlightened group share some thoughts on where or what I might be looking for? I am not strong on PTH technology.
Thanks all.
`hege
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