I'm an old dog, for sure, but may not be able to comfort you fatherly by
e-mail. I have been in the industry for decades, both commercial, MIL and
SPACE, and believe me, I have never seen any of our procucts 'smeared' with
silicon grease. The reason is obvious: you get a hell when you need repair.
Instead, you must make the construction in a way so that humidity is avoided
or removed or lead away or absorbed. The advantage with fairly unprotected
harnesses is that you can dry it. Can you place a shield that takes care of
droplets? Can you place absorbants somewhere? Do you use correct connectors
and sleeves? Etc. If you smear despite my advice, see that you leave no
spaces and voids that can act like water traps.
Brotherly
Inge
--------------------------------------------------
From: "Carl VanWormer" <[log in to unmask]>
Sent: den 23 August 2010 19:52
To: <[log in to unmask]>
Subject: [TN] humid environments and long term reliability
> We are considering conformal coating our boards that will go into a
> chassis that may be an occasional high humidity environment. I have
> been told that the humidity (and water) is "slowed down" by the
> conformal coating, and that good cleaning before the conformal coating
> is essential for reliability. Assuming we have done all we can do for
> the PC board assembly, my worry goes to the next level; the cables that
> connect between boards and also to the valves, relays, and sensors. Is
> it worth considering messing up the system with silicone grease smeared
> on all of the 2-pin, 5-pin, and 50 pin (IDC) plugs and sockets? I know
> some of the cute little phone-wire crimp-on IDC button connectors are
> filled with a dielectric grease, so it must have some value. And what
> about the IDC connector, with its pins just piercing the ribbon cable .
> . . Is there a long term reliability problem there, too?
>
>
>
> I'm looking for "fatherly guidance" on making a system that won't ever
> need a field service call.
>
>
>
> Thanks for tolerating my paranoia,
>
> Carl
>
>
>
>
>
>
>
> Carl Van Wormer, P.E., AE7GD
>
> Senior Hardware Engineer
>
> Cipher Systems
>
> 1800 NW 169th Place, Suite B-100
>
> Beaverton, OR 97006
>
> Cipher Systems (503) 617-7447 x 5163
>
> Direct Line (503) 425-5163
>
> [log in to unmask]
>
> This message may contain confidential and/or proprietary information,
> and is intended for the person/entity to whom it was originally
> addressed. Any use by others is strictly prohibited. If I sent this to
> you by mistake, please be nice and delete it, then tell me of my mistake
> so I can send it to the right person.
>
>
>
>
> ______________________________________________________________________
> 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
-----------------------------------------------------
|
