Thanks Werner,
it's really 'grams' in the IPC spec, I take my red pencil and make a correction. Guessed it was 6-10 g's which is a very handsome and kind level, far below what we test, so I understand it works good as screening. Thanks also for superBGA-warning, warpage is exactly what I see on some of these creeps.

Ingemar


-----Original Message-----
From: [log in to unmask] [mailto:[log in to unmask]]
Sent: den 28 september 2000 16:06
To: [log in to unmask]; [log in to unmask]
Subject: Re: [TN] Q for Werner E?


Hi Ingemar,
I sure hpe it says 6-10 grms, not grams. If it says grams than the document
got over-edited by staff thinking this is a typo. grms stands for 'g', the
Earth gravitational acceleration constant and rms stands for
root-mean-square, and is standard vibration terminology.
This is an effective ESS procedure for finding solder joints with latent
defects, and comes from some of the old military vibrational requirements.
The full details you would have to get from one of the vibration gurus, I am
not one of them.
In addition, be careful with superBGAs, they warp at high power dissipation
and can cause tension induced SJ failures.

Werner Engelmaier

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