TECHNET Archives

June 2006

TechNet@IPC.ORG

Options: Use Monospaced Font
Show Text Part by Default
Show All Mail Headers

Message: [<< First] [< Prev] [Next >] [Last >>]
Topic: [<< First] [< Prev] [Next >] [Last >>]
Author: [<< First] [< Prev] [Next >] [Last >>]

Print Reply
Subject:
From:
"Dehoyos, Ramon" <[log in to unmask]>
Reply To:
TechNet E-Mail Forum <[log in to unmask]>, Dehoyos, Ramon
Date:
Fri, 23 Jun 2006 08:31:55 -0400
Content-Type:
text/plain
Parts/Attachments:
text/plain (73 lines)
        Hi Kenny:
        Pardon me for not being explicit enough. I was just giving an
example of how coating can pull away and letting you know that perhaps
by doing  extra cleaning the probability of a chemical in the vias may
be eliminated.  Have you tried to scratch the surface that looks like
there is no coating. It just may be thin and the fluorescence additives
do not show reflection. Not all the surfaces hold the coating the same
way. Rougher surfaces hold it better than smooth. Flat, short surfaces
hold it better than sharp or tall..... I know of a group that atomizes
the dispensing of the coating to ensure even coating. The way that group
does it is by coating a thin layer of CC and letting it skin for 15
minutes and then recoat. Very slow process. Another way would be to
thicken the coating, increase viscosity.
        Regards,
        Ramon

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Bloomquist, Ken
Sent: Thursday, June 22, 2006 1:39 PM
To: [log in to unmask]
Subject: Re: [TN] Conformal Coat Voids

I've had Steve post a picture of the missing coating on the via's. I
hope this helps make things a little clearer. A picture's worth...

http://stevezeva.homestead.com/files/Via_Coating_Dewetting.JPG 

Thanks Steve for posting this picture.

KennyB

-----Original Message-----
From: Bloomquist, Ken [mailto:[log in to unmask]]
Sent: Thursday, June 22, 2006 9:44 AM
To: [log in to unmask]
Subject: Re: [TN] Conformal Coat Voids

Hi Ramon,

These voids have nothing to do with Kapton tape or silicone backed
adhesives. These are via's that are tiny and out in the middle of the
board. There is nothing else around them that is masked. The lack of
coating is only on the domed portion of the solder that is in the via
which protrudes slightly above the board surface. I'll try to get a
picture of the condition if the camera can pick up the black light.

Thanks,

KennyB

---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 1.8e 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
-----------------------------------------------------

---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 1.8e
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
-----------------------------------------------------

ATOM RSS1 RSS2