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Bubbling Barrels

#25766

Bubbling Barrels | 19 September, 2003

We have recently started building a new assembly that is exhibiting some strange behavior. We are seeing what look like blow holes in wave soldered joints. When the joints are touched up, the solder in the barrel will actually bubble up from the hole towards the lead tip. It looks like there may be moisture trying to escape during the reheating process.

Our wave recipe is fine and we aren't seeing the issue on other boards (that I know of). I've been trying to identify where moisture could be introduced in our process and have checked our fluxer air knive supply and changed out to fresh flux/thinner. I'm starting to think we may have a raw PCB issue.

Any ideas?

Thanks in advance.

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RDR

#25769

Bubbling Barrels | 19 September, 2003

You most likely have a raw fab problem, These PCBs need to be baked. We have this same thing now and then (only from one supplier) and baking has helped. I hope this is what your problem is.

Russ

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#25770

Bubbling Barrels | 19 September, 2003

Russ,

I feel a little better now.... Baking specs...... Can you give me a tip on where to look? It's a 4 layer, .062 and roughly 5 inches square.

Thanks.

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RDR

#25773

Bubbling Barrels | 19 September, 2003

Hoss, here is what we do, we start with a 12-24 hr. at 100C. and then test. Sometimes it takes longer and sometimes you could probably get away with 8 hours. You could increase the temp to shorten but I would not go above 375 deg. F however. Hope this helps

Russ

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#25774

Bubbling Barrels | 19 September, 2003

Russ,

I had arrived at basically the same specs here. Thanks for the effort.

Regards.

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