We do IPC class 3 plus for aero & medical. You won't really find much if
anything formally written in IPC that I have been able to locate.  IPC
A610E will be about as good as it gets. There is quite a bit of AABUS
also provided in customer specifications. Some of that makes sense and
some that no longer does.  Typically if the rework looks good enough to
meet the requirements as if it was the original coating, you should be
good to go. 

Perhaps the most critical part of reworking an area is to insure that
any trace of the stripping compound (if used) is removed, as many of
those are caustic. Little bit of a "catch 22" here, in that most high
reliability applications use chemical resistant 2 part UR coatings.  The
more rugged those coating are the more caustic a solution they require
to remove, hence  more risk to the rework area.  Same as with any other
PCBA process area... be sure  that you really need to perform the
targeted rework. 

Perhaps, NASA has something.

Rich Kraszewski/PLEXUS

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Gregg Owens
Sent: Friday, April 16, 2010 11:54 AM
To: [log in to unmask]
Subject: [TN] Conformal Coating Rework

I am looking for specific guidance/standard for conformal coating
rework. When conformal coating is removed how much overlap should the
new conformal coating overlap the existing conformal coating? I have
looked at IPC-7711 and J-STD-001 but found no specific call out. Any
suggestions (and yes, I know it depends....)? We are using AR and UR
type conformal coatings. Your thoughts and opinions are most
appreciated.

Gregg Owens
Technical Writer - Avionics
Space Exploration Technologies Corporation
1 Rocket Road | Hawthorne | CA | 90250
310-363-6533 | [log in to unmask]


______________________________________________________________________
This email has been scanned by the MessageLabs Email Security System.
For more information please contact helpdesk at x2960 or
[log in to unmask] 
______________________________________________________________________

---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 15.0
To unsubscribe, send a message to [log in to unmask] with following text
in
the BODY (NOT the subject field): SIGNOFF Technet
To temporarily halt or (re-start) delivery of Technet send e-mail to
[log in to unmask]: SET Technet NOMAIL or (MAIL)
To receive ONE mailing per day of all the posts: send e-mail to
[log in to unmask]: SET Technet Digest
Search the archives of previous posts at:
http://listserv.ipc.org/archives
Please visit IPC web site
http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional
information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100
ext.2815
-----------------------------------------------------

______________________________________________________________________
This email has been scanned by the MessageLabs Email Security System.
For more information please contact helpdesk at x2960 or [log in to unmask] 
______________________________________________________________________

---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 15.0
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF Technet
To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL)
To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest
Search the archives of previous posts at: http://listserv.ipc.org/archives
Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815
-----------------------------------------------------