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Date: | Fri, 12 Mar 2010 16:32:48 -0600 |
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Hi Inge - I recommend you use an underfill that you would use for BGAs. We
had a similar situation and the careful application of the underfill we
normally use for BGAs was a successful resolution.
Dave Hillman
Rockwell Collins
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Inge <[log in to unmask]>
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03/12/2010 12:47 PM
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[TN] Vibration issue
Hi all,
we are making a very vital part for a aircraft builder. Problem with
TQFPs, some 200 legs. There are resonance peaks that kill the package
legs.
Redesign is not to think of from the customer, so we must do something on
inside of the box. One solution (not popular) is to use a string of a
glue
along the leg rows in order to lock them. Another is to place a vibration
dampening mat on one side of the board. That one is more tricky , but
there
is a US company with lots of stuff for that purpose. Anyone with
experience from this area? I should add that not all legs are broken, just
one or two after 100 hs of random vibration, but that is of course not
acceptable. BGAs would solve the problem, but there is no time for
redesign.
I'm sorry for coming with a serious message at this holy time of the
week.
Thanks
/Inge
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