One possibility is the plating may be insufficiently ductile. The Z axis
expansion over the Tg during HASL or soldering will then cause the
barrel to pop as you describe.

Brian

Frank Davies wrote:

>  Just some advice if possible.  I have a board that shows a plating
> crack in the barrel and another with a plating crack at the knee
> (corner). The hole is a via .3mm with about 20 to 21 microns of
> plating (checked by micro section) This is a first this year and
> cannot find any cause. Could someone out there give me a starting
> point please. Thank you first.Frank

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