Hi folks,

with this issue we have a fling or a  big issue. This is what  I knew up to now, supported by other papers. Thank You very  much.

On the other hand there is existing a paper which  tells  exactly  the opposite:

"Vibration Testing and Analysis of Ball grid Array Package  Solder Joints" from  Shaw Fong Wong e.a.  Intel Technology 1-4244-0984-5/07/  2007 IEEE

It says in the conclusion:
The comparison of SnAgCu and SnPb fatigue curves clearly indicated the better performance of SAC solder system under  high cycle fatigue test.

 
I had not the time up to now to compare  all boundary conditions, but in the paper of INTEL are  Weibull curves drawn, which show that for cycles >  10**5  SAC survives SnPb. Vibration tests from about one hour ore more have more  than 10**5  cycles..

This  paper is  already quoted in other papers and You can imagine that there is temporary a  big uncertainity in the lead free society.

I would  be  happy if  we can discuss about  the big differences  in the boundary conditions  of these two worlds.

I started already comparing them, but I am interested in Your opinions. Is it the different annealing history or what?

Sincerely

Michael Jeremias   
Industrial Engineering (OPPI41) 
Electronics Production 
((( Defence Electronics 
EADS Deutschland GmbH 
89077 Ulm
Tel.: +49 (0) 7 31.3 92-5533
Fax:     +49 (0) 7 31.3 92-73 15
E-Fax: +49 (0) 7 31.3 92-20 5533
P Before printing, think about the environment ! 
 


-----Ursprüngliche Nachricht-----
Von: TechNet [mailto:[log in to unmask]] Im Auftrag von Joe Fjelstad
Gesendet: Montag, 8. Dezember 2008 21:45
An: [log in to unmask]
Betreff: [TN] vibration testing of tin-lead and lead-free solder joints


 
Greetings  folks
Found this  on the wires today... (Cut it earlier out but lost the link but I am  sure I am not the only one who read it. However I can go dig it up if  
there is interest)   
Why are we  still using lead-free solder again? So it goes.... 
Joe
"Davide de  Maio of National Physical Laboratory discussed the high frequency vibration  testing of tin-lead and lead-free solder joints, with reference to automotive  and aerospace electronics--a grim reminder that 80% of failures in airborne  electronics were attributable to vibration and shock. A test piece had been  designed representing a single solder joint between two copper components, which  was tested to failure at frequencies of 400Hz and 800Hz. A range of SAC  lead-free solders had been evaluated, with tin-lead as a comparison. 
The  tin-lead solder outperformed the lead-free examples, especially at the higher  frequency. In general, failure occurred at or near the intermetallic interface,  which would be expected to be the most stressed area. Of the SAC alloys,  performance at 400Hz was better the higher the silver content. Annealing of SAC  had a deleterious effect on performance at both 400Hz and 800Hz."
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