Hi Leland - It may come as a surprise to many engineers but many metal 
alloys actually have a "DNA" which can be traced back to original 
processes and/or original sources. Unfortunately, unless you can find an 
elemental signature difference in the solder alloy you use in your wave 
solder process versus your reflow process (which you will need something 
more sophisticated that standard SEM assessment) you will not be able to 
determine which process may have produced the solder ball. I don't believe 
that cross-sectional analysis will be beneficial unless you have some 
baseline for comparison.

Dave Hillman
Rockwell Collins
[log in to unmask]




Leland Woodall <[log in to unmask]> 
Sent by: TechNet <[log in to unmask]>
10/28/2009 06:54 AM
Please respond to
TechNet E-Mail Forum <[log in to unmask]>; Please respond to
Leland Woodall <[log in to unmask]>


To
[log in to unmask]
cc

Subject
[TN] Birth of a Solderball






TechNetters,

Is there any possible way to determine the origin of a solder ball?
We've had a failure because of one, and we're trying to determine
whether it came from our SMT or wave soldering process.

We use SAC305 at both, so using the SEM to determine alloy composition
is not really helping.

The ball itself is spherical with no "tails" and quite shiny in
appearance.

If we cross section the ball, will we see a difference in grain
structure due to the differences in cool down rates?  Is there anything
else we can use or do?

Thanks in advance for your help!

Leland

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


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