Hi Jon.
We—the industry, is learning, more often than not the hard way.
Doing Pb-free with more complex assemblies is a different animal than all those throw-away consumer electronics.
I think in your "Lead Free Training" stuff, they simply copied some of what worked with good, old SnPb.
Any additional soldering operations will do some damage—the higher the T, the more the damage. This means, avoid additional solder-T excursions if at all possible. Do not do rework for purely cosmetic reasons—and remember, many of these documents are mostly cosmetic rather than really necessary for reliable functionality.
Also, if rework is REALLY necessary, preheat the assembly—and cool very slowly [=<1.5C/sec] from either reflow or rework soldering.
Werner
Upcoming workshops:
May 21, IPC Int. Conference on Reliability and Quality of Lead-Free Electronics, Frankfurt, Germany,
“Reliability Issues and Solution Options for Pb-Free Soldered Electronic Products”
May 26, FED Seminar, Stuttgart, Germany,
“Bleifreie Lötprozesse—Frühausfälle, Qualität, Zuverlässigkeit”
June 8, SMT/HYBRID/PACKAGING 2010, Nürnberg, Germany,
“Reliability Issues with Lead-Free Soldering”
-----Original Message-----
From: Roberts, Jon (SA-1) <[log in to unmask]>
To: [log in to unmask]
Sent: Thu, Mar 11, 2010 9:31 am
Subject: [TN] LEAD FREE REWORK QUESTION
Good morning to all, I recently purchased a Lead Free Training
materials. I was asked to provide lead free training to a very small
number of operators. During the presentation of that purchased training
material it stated in order to rework a solder connection, you remove
the solder and component. Then you reinstall and solder (called
remanufactured). Is that the best way and if so why? Maybe Werner
will know and any of you that are doing lead free soldering and have to
rework. Doing our design stage (IR&D) for new products we are going
toward lead free and engineering needs parts changed or add mod wires
prior to qual testing). Thanks, Jon
______________________________________________________________________
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
-----------------------------------------------------
|
