I'm not sure who wrote this, but I would like to hear more.  How does
a direct connect via increase the incidence of pink ring?  Perhaps my
understanding of what creates pink ring is in error but I would think
the geometries and chemistries at the hole wall is the same either way.

Also, what do you TechNetters say about pink ring?  Is is a functional
defect or not?  How many board failures have you seen attributed to pink
ring (whether thru delamination, via failure, or whatever)?  Please note
the word failures - not rejections (although that might be interesting
to know as well).  As we all know, sometimes requirements are based on
"that's the way we've always done it" rather than on real data.

[log in to unmask]
Don Walker

>    By eliminating thermals at via locations you significantly increase
>    the probability of creating pink ring.  Depending on who you talk to
>    will determine if pink ring is a functional defect or not.  If your
>    finished specification for your board manufacturer states "No pink
>    ring allowed" you are setting him up for failure.  If pink ring is a
>    non issue with your company and this is reflected in your
>    specification this is a non issue.  The diameter of the center pad,
>    width of the spokes and diameter of the clearance around the center
>    pad are significant factors that contribute to the amount of pink ring
>    present.

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