Printed Circuit Board Assembly & PCB Design SMT Electronics Assembly Manufacturing Forum

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SMT electronics assembly manufacturing forum.


Water in TH cap sleeves

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#73168

Water in TH cap sleeves | 26 November, 2014

We have a lot of large through hole caps and we run everything through a wash process. Unfortunately water makes it's way inside the sleeves that the caps are shrink wrapped in. Has anyone found a way to prevent this from happening? We are running at 125 psi and 140 degrees water temp

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#73172

Water in TH cap sleeves | 26 November, 2014

While I can't directly answer your question, we've had the same problem here occasionally. Our wash parameters are roughly the same as yours. It seems to be correlated to the diameter of the cap (larger caps will balloon while most smaller caps are unaffected). We work around that here by installing the problematic caps after wash.

You might try some latex mask on the top of the cap to help seal the sleeve. Or possibly a baking cycle after wash to drive the water out? I haven't personally tried either of these, just a thought.

Hope that helps!

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#73181

Water in TH cap sleeves | 1 December, 2014

We had the same problem too. Water would remain under the caps even after a bake out. We saw this numerous times when the caps were removed after the wash and bake. The only fix was to hand solder the large electrolytics.

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