using DI water and check the surface contact angle, if it is <30  
degree, you are more less OK (provide you did coating material  
compatibility study already), 40 degree you need to make sure your  
coating batch is fresh (not near the end of shelf life), 45 degree,  
you got yield problem... you might spot it or not are pure luck...  
IMHO....
On Aug 28, 2017, at 10:26 AM, Richard Kraszewski wrote:

> I seem to  recall numerous industry articles (Pauls, Keeping,  
> etc.)  referencing  that  ideally the surface energy of  a PCBA  
> should be >~ 40 dyne cm  prior to coating.
> I have searched my files but cannot seem to find any of  them now.  
> Only some referencing the need   to consider surface energy.
>
> Does someone have any  that reference " >~ 40 dyne cm  prior to  
> coating"  readily available  that they can forward to me?
>
> Thanks
>
> Rich  Kraszewski
> Senior Staff Process Engineer
> Plexus Engineering Solutions
>
>
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