Hi Chris,
If you get the ITRI Report 'PWB Hole-To-Land Misregistration: Causes and
Reliability, Project Final Report", you may be a little careful in applying
the conclusions. I am not saying that the conclusions are wrong, but that
based on the test performed, the conclusions may be a stretch. From a
reliability point-of-view of the PTH barrel-to-land interconnect, the most
severe loading occurs during excursions to soldering temperatures not thermal
cycling, even from -65 to +125C. That is because the largest thermal
expansion of the epoxy that causes the radial barrel compression and land
rotations occurs only at temperatures above Tg.

Werner Engelmaier
Engelmaier Associates, Inc.
Electronic Packaging, Interconnection and Reliability Consulting
23 Gunther Street
Mendham, NJ  07945  USA
Phone & Fax: 973-543-2747
E-mail: [log in to unmask]