Kathy,

We've looked at several of the items you mentioned in the course of testing. RH in both facilities is pretty similar at 30-40%. Handsoldering the components and then subjecting them to the same wash does not cause the failures. We have tried baking them prior to installation with no change in results. We've also done hot and cold shocking of the components in water baths to try and stress the seal. The vendor also states that we may see some fogging in some parts due to trapped moisture; unfortunately our medical customer wants to see none. 

Rick


-----Original Message-----
From: Kathy Kuhlow [mailto:[log in to unmask]]
Sent: Wednesday, June 04, 2003 1:58 PM
To: [log in to unmask]
Subject: Re: [TN] Wave Solder Advice?


It seems odd that with so many devices used that you all of a sudden have a problem.  With the move to a new building are the environment conditions the same?  What has the Rh been in the new building versus the old building?  Is it possible that the parts you have were exposed to humidity?  Do you have access to try and prebake a few parts and then wave/wash them?  Can you weigh a part prebake and then weigh it post bake to see the weight difference?  

Is it possible to wash a part without the inline washer and see if you get the same entrapment?  I have seen spray over spray washers actually drive moisture into devices because of the pressure.  Has the pressure been increased in anyway?  Does the part get pre-prepped prior to wave?  Is it possible that the lead prep actually cracked and exposed the internals?  

To me the topside temp sounds about right.  We typically try to target in about that same range.  Although 100 is the very high side.  

Kat

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