Bill: Assuming poorly soldered terminations is the reason the components are falling
from the boards, your customer is correct.  Vibration testing is an excellent method
for identifying poorly soldered teminations.

As you say vibration testing can be over-done.  In assessing that, useful information
about the test [in addition to the duration] would be frequency and "amplitude" of
vibration.

Yano, if your customer is seeing field failures, it seems reasonable for them to take
steps to protect their customer from failing product and to work to correct the
problem.

So, why are you doing thermal screening, while your customers is using vibratory
screening?  Is there more than one failure mode?

Dave Fish


[log in to unmask] wrote:

> I am asking anyone for comments and help!!!  I have a customer who is using a
> vibration test of 10 minutes to determine any "workmanship" errors on SMT
> assemblies for RF applications.  He seems to be having problems with caps
> (1206, 0805, 1210) on assemblies because these chips are randomly failing
> either in the field or at pre-test.  We have run some thermal tests on
> various reels of components (samples of ten pcs. per reel) without finding
> any defects.  We have run some tests on assemblies after all SMT operations
> without finding any defects.  My question is can the vibration testing be
> affecting the reliability of the caps?  Is vibration testing a common
> practice?  What testing criteria should be used for vibration testing---if at
> all?
>
> Thank all for the help!!  Please send responses to Bill Black at
> [log in to unmask]
>
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