Hi again,

thought you got rid of me?

Thanks for all the answers, very pertinent comments. However, I would like to clarify a little bit more what I actually wanted.

Please note that the original question is exactly what it implies, what would be the reliability of a solder joint. The scope does not extend to components falling off the board or not, this is taken care of. And we do double sided BGA boards for almost 11 years now, with no returns from the field. The fact that the doubly reflowed BGA would have elongated joints can only improve compliance, therefore the reliability.

To rephrase my question: how will a second reflow affect a properly formed solder joint, if the second reflow is not as hot and with smaller dwell time with respect to the parameters required to properly form the joint.   So the optimal IMC is already formed. The crystalization mechanism of the joint after the second reflow is the only difference that I see, but this should be taken care of in time by the creep.

I would tend to say that a lower temp and dwell secondary reflow is of no concern, but is it so? Are this kind of things computable, is there any theory that can clarify this? I want to get beyond the common sense.

Thanks again,

Ioan

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