Hi Roger,
There are some results on this in IPC-TR-579 "Round Robin Reliability
Evaluation of Small Diameter Plated Through Holes in Printed Wiring Boards."
There is indication, that the no-functional lands provide a very moderate
reliability improvement, but that any decrease in quality due to the more
difficult manufacturing processes might negate this benefit.
...and the MoonMan is absolutely correct when he writes:
>Your desire to save real estate is a good one. Just make sure the copper
>thickness is there and the ductility is high.
He is talking  abouit 1.5 mils, not 0.8 mils of copper in the PTV; if you get
thin pating, the thermal expansion of the resin during any soldering process
will plastically bulge the copper barrel walls inward and create a space
between the barrel walls and the resin hole after shrinking during cooling.

Werner Engelmaier
Engelmaier Associates, L.C.
Electronic Packaging, Interconnection and Reliability Consulting
7 Jasmine Run
Ormond Beach, FL  32174  USA
Phone: 386-437-8747, Fax: 386-437-8737
E-mail: [log in to unmask], Website: www.engelmaier.com

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