Don't know where those unwanted question marks come from that are supposed
to be either quotation marks or commas, except as indended as question
marks. Is it the copy from MSWord and paste to this window doing it? How to
not let this happen?

Also, concerning the question at hand, a point about plating high aspect
ratio holes. If memory serves, acid copper "throws" much better than pyro.
Hence, it is used mostly and no problem with this but for my concerns about
plated copper ductility.

As in 3.2.6.2 in 6012, I believe, the minimum ductility shall be 6%. I don't
know how his low number is not a problem in high ratio holes expanding in
the z axis at 50 ppm or so. In the good old days, a couple of years ago
using pyro, I saw numbers as high as 30% coming out of some plating tanks.
My concern is at the ppm rate indicated, z axis hole elongation could easily
exceed the ability for low ductility copper, at over 10%, and see the hole
come apart even if minimum plating thicknesses are assured.

What's wrong with my thinking here?

Earl Moon

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