Foreign material contamination maybe, oily residue from manufacturing process?  Is it the same place on all boards that fail to wet?   

pat

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Steve Gregory
Sent: Tuesday, May 07, 2013 8:48 AM
To: [log in to unmask]
Subject: [TN] Irritating ENIG Non-wetting

Hi All,

 

We just were running some boards (ENIG finished) where we're seeing this sporadic non-wetting on some of the pads:

 

http://stevezeva.homestead.com/PKG2.jpg

 

http://stevezeva.homestead.com/PKG3.jpg

 

http://stevezeva.homestead.com/PKG4.jpg

 

Usually it's just a few pads and the rest of the board is fine. We get the boards in packs of 20, and it's only a couple or so out of the pack that exhibit the problem. It's just enough to be irritating.

 

When we touch the locations up with a soldering iron they wet fine.
We're using a 63/37 water soluble paste, and the problem doesn't confine itself to just certain pads or parts, it's random.

 

Like I said it's just enough to be irritating.....   /:o[

 

Steve Gregory

 


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