Here's my two cents worth.
     It doesn't matter if the case is not coated. 
     Conformal coating isn't a true vapor barrier anyway.
     It's purpose is to protect exposed, conductive features from contact 
     with liquids and conductive particles. 
     If you are certain that all your circuit is protected, and your 
     customer can be educated to the true purpose of cc, then go for it.
     By the way, does your cc have a Uv trace material added for coating 
     verification? If it does, it could help prove that the critical 
     elements (traces and leads) of the circuit are protected.
     
     The views stated above are not necessarily those of my employer.
     
     Lyn R. Lynch
     [log in to unmask]


______________________________ Reply Separator _________________________________
Subject: FWD: pwb-cca : conformal coating
Author:  [log in to unmask] at internet
Date:    10/23/96 4:49 AM


Technet,
     
I'm forwarding this from a colleague.
     
Cindy Kemp
Lockheed Martin
Orlando, FL
*******************************************************************************
     
From: [log in to unmask]
Date: Tue, 22 Oct 96 16:35:22 EDT
Message-Id: <[log in to unmask]> 
To: [log in to unmask]
Subject: pwb-cca : conformal coating 
Sender: [log in to unmask]
Precedence: bulk
     
hi group;
     
We are finding that in designs using conformal coating (UR) over plastic parts 
that the cc is dewetting on the parts.
     
Question - is this seen as a problem ?
     
I am proposing that a note should be added to our designs as follows:
     
 CONFORMAL COAT DEWETTING ON PLASTIC ENCAPSULATED MICROCIRCUIT 
 COMPONENT BODY IS ACCEPTABLE.
     
If there is a better way please let me here from you.
     
What is the real would doing ?
     
     
   thanx; Skip Greb
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