TECHNET Archives

March 2004

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:
Brian Ellis <[log in to unmask]>
Reply To:
TechNet E-Mail Forum.
Date:
Wed, 17 Mar 2004 14:11:04 +0200
Content-Type:
text/plain
Parts/Attachments:
text/plain (54 lines)
Sorry to be patronising, but have you thought that a "no-clean" flux is
designed not to be cleaned? You don't say why and how you have attempted
the cleaning. It is not very clever to try and clean just one side.
Usually, all you do is partially clean it by removing the inactive
components and smearing the dangerous, active components all over the
place, probably reducing the reliability of your assembly. Changing the
mask to matt may give a cosmetically better result, but it will be still
just as bad, even if you can't see the residues as much: they will still
be there.

If you tell us the how and the why, we may be able to advise you better.

Brian

Yordan Venev wrote:
> Hi TechNetters!
>
> We face a problem with flux residues on the bottom (solder) side of the PCB
> after wave-soldering. We have tried to clean only the bottom side since
> (usually) we do not clean the PCB after assembling, but it is very hard and
> nearly impossible task! The PWB is FR4 substrate and the flux we use is
> alcohol based no-clean for foam. I cannot specify the solder mask as type,
> but what is obvious is the shining smooth surface. I have a strong feeling
> that for better performance in solder wave process the mask should have math
> surface. What should I specify to the PWB manufacturer as solder mask type?
> And yet could we optimize the process in some way to reduce or even avoid
> such problems? We try to follow the flux manufacturer's instruction about
> application, preheat and etc.
>
> Best regards,
> Yordan Venev
>
> ---------------------------------------------------
> 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 847-509-9700 ext.5315
> -----------------------------------------------------
>
>

---------------------------------------------------
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 847-509-9700 ext.5315
-----------------------------------------------------

ATOM RSS1 RSS2