Thanks everyone for your input!  Some great questions have been raised,
most of which I can't answer at the moment, but it has given us some
good starting points to help us research this problem with our process
engineers and board vendors.  When the root cause is determined, I'll
post that information for the archives.

Thanks!

- Jon DeGenova


> ----- Original Message -----
> From: "DeGenova, Jon R." <[log in to unmask]>
> To: [log in to unmask]
> Subject: [LF] Lead free parts falling off boards
> Date:         Fri, 27 Oct 2006 14:19:01 -0400
> 
> 
> We have some PCB assemblies, measuring approximately 11x13 inches in 
> size, .062" thick, with very dense population on both sides.  They are

> mostly SMT, including about 3 BGAs.  These ran fine on as leaded 
> boards, but in our first runs using a lead-free process and an ENIG 
> board finish we're seeing a strange problem.  Reports are that parts 
> are 'falling off', not in large numbers, but enough to raise an 
> eyebrow.  Mostly these are passives that are coming off after a double

> reflow process (there was no wave soldering done on the boards at the 
> point that this was noticed).  And in some cases, the entire PAD was 
> coming up off the circuit board.  Has anyone seen similar issues? I'd 
> like to give our assembly personnel some advice on where to start
investigating.
> 
> Thanks,
> Jon DeGenova
> 
> 
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