Hi Selim,

After vacuum baking did you add desiccant and seal the board?  If the board is left open to ambient conditions, it will most likely absorb back everything that you baked/vacuumed out. 

Best regards, 
Dave

David W. Bergman
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IPC - Association Connecting Electronics Industries
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-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Avni Selim Özçukurlu
Sent: Monday, July 01, 2013 6:36 AM
To: Technet
Subject: [TN] Moisture in PCB

Hello All,


 


After a wave solder process of a PCB with lots of through-hole components on it, I have seen that there are popcorn part near via on that PCB. The flatness of the first layer of the PCB is gone after that process. I think that moisture remaind inside PCB gets outsite during the wave solder process and cause this problem. I didn't put the PCB in a vacuum oven before wave solder. Is it possible that the problem is related of this. Is there any alternative solution about that problem?


 

Actually I applied the heat up and vacuum to empty PCB before all process of manufacturing. After that vacuum oven process, it has passed about 10 days to start the wave solder process. During that 10 days, did PCB get moisture inside?

 

Thank you advance.

 

Selim.


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