Blair

I suspect your contamination is the result of silicone that is  
impairing the coating adhesion.

My recommendation is to oven bake the boards (assemblies?) overnight  
at around 80DegC. If my suspicions are correct, your coating adhesion  
problem will disappear.

I am basing this on your comment that a ROSE test showed "no ionic  
contamination" - that I do not believe, low maybe but no.... Can you  
tell me what value was read?

Graham Naisbitt

Gen3 Systems Limted
Engineering Reliability in Electronics


On 21 Feb 2008, at 20:52, Blair Hogg wrote:

> 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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