Hi Ray,
A competent PCB shop should not have any problem producing a double-sided
FR-4 PCB with 28-mil vias in a 90-mil thick board. The reliability of these
PTVs will depend on, besides the obvious PCB quality issues, on how what kind
and numbers of solder temperature excursions this PCB will see as well as how
severe the operational environment will be.

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]

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