Typically the goal is to protect conductive surfaces, and board edges don't often have conductive surfaces (and if they do, they might need to stay exposed).

If you have seen the board edges coated it is probably a result of the method that was used to coat them (spraying or dipping), not because it was required.



On Thu, 1 Mar 2018 09:45:26 -0600, Caitlen Gahm <[log in to unmask]> wrote:

>Greetings,
>
>We are wondering what the general thought is regarding whether or not the edge of a CCA/PWB needs to be conformally coated?  We received CCA's from a supplier and noticed that the edges were not coated.  Our thinking thus far is that since our drawing does not state that coating on the edge is optional or not required, it would be required.  
>
>What we are curious to know is what the general consensus is regarding whether or not it is necessary to coat the edge of the CCA and instances when this would or would not be desired.
>
>Thank you,
>Caitlen Gahm
>Materials and Process Engineer
>Crane Aerospace & Electronics