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:
Connie Korth <[log in to unmask]>
Reply To:
Date:
Mon, 22 Mar 2004 12:31:06 -0600
Content-Type:
text/plain
Parts/Attachments:
text/plain (134 lines)
Thank you for your response.  It was very helpful.  Our customers would not
accept this type of repair.  We repair per IPC-7721.  It is that I was
caught by surprise when this question came up and I didn't have a good in
depth answer for the group.

Thanks again for your time

Connie

-----Original Message-----
From:   Brooks,Bill [SMTP:[log in to unmask]]
Sent:   Monday, March 22, 2004 11:53 AM
To:     [log in to unmask]
Subject:        Re: [TN] Solder bridging

Interesting question Connie...

There are applications where a 'solder bridge' is a perfectly acceptable
practice... and there are applications where it would not be. Although I
cannot think of an example where it would not work exactly, perhaps a high
current application or a high vibration application might be susceptible to
out of the ordinary failure happening... but if so, you would expect the
same or even more severe stresses upon the surface mounted components.
Solder will loose its ductility or 'work harden' when stresses in tension
or
torsion by thermal expansion and contraction in repeated cycles are applied
to the joint.. All components are exposed to this stress by the environment
the board is subjected to.

The problem with using a solder bridge as a 'repair' is that it really has
no survive-ability through the soldering processes, it would have to be
applied after all the reflow or wave soldering processes were done. Any
re-exposure to those temps would cause the solder bridge to reflow and
disconnect the bridge. I assume that is why in most RF applications we used
a small square of thin silver plated copper as a 'shorting bar' and
soldered
it to the 'pads' to created the short when we needed an 'RF stub' on a
conductor to change it's impedance. I would suppose that if you used a
method like that for your repair, it would be more likely to survive
exposure to soldering process temps if needed.

Many commercial products use solder bridge 'jumpers' in their designs,
transistor radios, electronic toys, things like that with high volume low
cost manufacturing that is really not a repairable item and is expected to
be a throw away when it fails. These are usually made of CEM1 and are
single
sided boards that are 'stamped' out in very high volume.

I hope that information helps a bit... you will have to discuss the
application of the board with your vendor, but I expect that your customer
would see that sort of 'repair' as an unacceptable...

In fact, there may be a IPC spec on acceptable repair for printed circuit
boards... I know the military had guidelines printed up that were used by
military contractors. Perhaps they have published something along those
lines in the past, I'm just not sure if it exists.

Best Regards,

Bill Brooks
PCB Design Engineer , C.I.D., C.I.I.
Tel: (760)597-1500 Ext 3772 Fax: (760)597-1510

-----Original Message-----
From: Connie Korth [mailto:[log in to unmask]]
Sent: Monday, March 22, 2004 9:15 AM
To: [log in to unmask]
Subject: [TN] Solder bridging

        Scenario:

        We have a conductor that was cut with an exacto by accident.

        Question:

        Why can't we just scrape off the solder mask and bridge solder over
it?
        Would that be a legal fix?

        The person questioned wasn't  really sure what the true explanation
of  that should be, since solder is what holds everything together.

        I told him I would solicit help from all of you.  Any input will be
greatly     appreciated.

        Thanks

        Connie Korth
        Reptron Mfg. Services
        Hibbing, MN 55746
        Quality Specialist
        [log in to unmask]




---------------------------------------------------
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
-----------------------------------------------------

---------------------------------------------------
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