If the glue dots are properly sized and cured correctly there should be no
issues with flux entrapment during the wave soldering process.  It is very
common for manufacturers to glue bottom side components and solder the
bottom side components in the wave process (no paste necessary).  You will
have to be sure the components are such that some solder joints will not
be shadowed by the ones in front of it, and the finest pitch doesn't lead
to bridging.  Good luck.


----- Message from "Morse, Carrie" <[log in to unmask]> on Mon, 20 Oct
2003 18:15:55 -0400 -----
Subject:
Re: SMT Glue and Paste with Wavesolder
You may also want to try intrusive reflow.

But, to answer your question -- One of the inherent problems with this
process is getting glue into the paste and entrapping flux which will
cause reliability issues.

Another solution which may work is simply to mask off those open areas
using either a wave pallet, or, if the cost is prohibitive, mask with
Kapton (which is also expensive).

-Carrie

-----Original Message-----
From: Richard Lepa [mailto:[log in to unmask]]
Sent: Monday, October 20, 2003 5:35 PM
To: [log in to unmask]
Subject: [TN] SMT Glue and Paste with Wavesolder


Hello Technetters,

We have a very challenging board that has quite a high quantity of SMT
parts
on the bottom side, both Rs and Cs and SOICs.  The problem is that I
cannot
use the chipwave on the soldering machine because there are large open
areas
on the topside of the boards where the solder will flood through.  Since I
can't use the chipwave I get a lot of solder skips in addition to
bridging.


The question is:  Has anyone ever used the glue/paste/place/reflow process
and then used the wavesolder to re-solder the bottomside SMT parts and
solder the thru-hole parts?  Are there any inherent problems with using
this
process?  Would this process reduce reliability of the parts due to
increased stress levels and intermetallics.  Your help will be greatly
appreciated.

Thanks,

Richard Lepa
Manufacturing Engineer

Brian J. Toleno, Ph.D.
Sr. Applications Chemist
Loctite Electronics
15051 East Don Julian Rd
Industry, CA 91746
Ph: 626-968-6511 x304

---------------------------------------------------
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
-----------------------------------------------------
Cell: 626-215-0879