It's neccessary to dry PCBs?

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Hello. I don't know if is neccesary to dry all pcbs before ... - Nov 24, 2006 by Jose Luis

Almost all boards are hydroscopic. In this, the epoxy holdi... - Nov 28, 2006 by davef

Jose Luis

#45535

It's neccessary to dry PCBs? | 24 November, 2006

Hello. I don't know if is neccesary to dry all pcbs before gegin the proccess, or depend of the type of pcbs. It's neccessary to bake the pcbs and components?, only components?.... What proccess do you recomend?. I read that is convenient bake the pcbs at 125�C during 12 hours. It's correct?.

All this is because I detected some solder problems in the circuits (with components), and I think, that the problem was in the storage of the pcbs, and, perhaps, the components too.....I don't know...

Thank you in advance..

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davef

#45734

It's neccessary to dry PCBs? | 28 November, 2006

Almost all boards are hydroscopic. In this, the epoxy holding the board together absorbs moisture.

Almost all components are hydroscopic. In this, the epoxy encapsulating the component together absorbs moisture.

So, as you heat the board / component towards the boiling point of water, the moisture becomes more active and moves toward coming a vapor. Is the moisture moves towards becoming a vapor, it increases in volume. You get the picture ...

Your bake recipe is typical for bare boards. J-STD-033 suggests bake recipes for components. Search the fine SMTnet Archives for bake recipes. For more, look here: * http://www.smtinfo.net/Db/_Moisture%20Sensitivity.html

* http://www.google.com/search?sourceid=navclient&ie=UTF-8&rls=GGLC,GGLC:1969-53,GGLC:en&q=moisture+sensitive+components

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