Techneters, I need your help:

I'm  curious about the critical temperature and time
values  regarding BGAs.  Do the Component Manufactures
have one set of limits, and  do PCB Assembly Shops
have another set of limits.  Companies like ours are
many times removed from the component manufacturers.
The industry default profile slopes are generally
built on solder paste characteristics.  Is this a
sound practice?

As I travel and interface with other engineers I find
that generally the solder paste manufactures recommend
a maximum temperature of 230 degrees C.  While the
reflow oven profilers max.-out at about 220 degrees C.
 Then the BGA rework engineers tend to agree that 210
degrees C. is the maximum temperature.  And as for
times, well most discussions have them varying between
45 seconds to 90 plus seconds.

Therefore:

1.  Are there any general rules for the maximum
temperature that BGAs can tolerate,?

2.  Are there any general rules for the maximum time
that BGAs can tolerate elevated temperatures?

I thank you for sharing your thoughts and wisdom.

thanx

Bill Butman
Circuit Technology Center
[log in to unmask]

=====
Bill Butman
Circuit Technology Center
45 Research Drive
Haverhill, MA 01832

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