Bev,
In the spirit of generalities my answer would be "if you can detect it, it is too big!"
The end of the crack is a major stress concentration point and will propagate rapidly.
Of course if you wait a few more cycles the crack will get really big and then it is definitely "big
enough".
A better question would be how do you distinguish between a crack and a void?
David A. Douthit
Manager
LoCan LLC
Bev Christian wrote:
> Hopefully this will start off a nice discussion. I have kept it general for
> that purpose.
>
> Shades of voids in BGAs... How big of a crack in thermally cycled solder
> joints is too big of a crack?
>
> Bev Christian
> Research in Motion
>
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