Before you dig too deep in your pocket, you should have someone try an
FTIR scan. Take a quick look at:

http://www.ipc.org/4.0_Knowledge/4.1_Standards/test/2.3.39C.pdf

Nice thing about this technique is the solvent it recommends.
Acetonitrile will dissolve about any organic residue out there and it's
easy to evaporate for analysis.  A good FTIR data base should at least
get you close to the general class of chemical you're dealing with and
at minimum provide you with a direction. 

A complicating issue with any analysis might be that:

#1 - you are dealing with multiple chemical compounds in the residue.

#2- this is not a residue at all, but an attack/discoloration of the
surface.


Rich K / GTS
847-621-7310
 

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Blair Hogg
Sent: Thursday, February 21, 2008 3:53 PM
To: [log in to unmask]
Subject: [TN] Residues

We are having an issues with printed circuit boards showing residues, 
that become more prevalent after heating cycles. It leaves a shiny /
oily 
looking film that is somewhat splotchy. Sorry for all these technical 
terms. 

I'm suspecting undercured epoxy, and I am currently looking to send 
some out for chemical analysis. I have one lab quoting IC, and another's

website also recommends FT-IR. The supplier performed a ROSE test 
and says there is no ionic contamination. The biggest problem we are 
having is with conformal coating adherance. Due to certain components 
on the one board that gives us trouble we aren't able to run it trhough 
our aqueous wash cycle. 

Is Ion Chromatography the right test? Any other suggestions?

Thanks,

Blair

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