Expansion on previous E-Mail given the E-Mail from gfranck: Previously: You certainly will not get the concave solder fillet without surface pads, but through-hole connections have significant redundancies as compared to SMT solder joints and that should not adversely impact reliability. This of course assumes that the design is otherwise properly designed. Since you still have pads on the side from which repairs are done, repair operations should also not be impacted. Added: Z-axis expansion of a .093", 14 layer board is always a concern. Normally the loading of the PTH is in the middle of the PCB (this is where failures occur with the exception of failures due to land rotation at the surface). My assumption is that you use high Tg (180oC) resin and E-3 HTE copper foils, control maximum possible temperatures during all soldering processes, and plate at least 1 mil (1.2 to 1.4 mils is better) of copper. Plating good uniform copper into a .035" (?) drilled hole should not be a problem with an aspect ratio of ~3. CTE of the PWB in the z-axis is 50+ppm/oC below Tg and 300+ ppm/oC above Tg more than the copper. Having said all that you certainly will have a shift of the location of maximum loading towards the padless PWB side, but my initial guess is that the maximum load will not significantly increase, particularly when all layers have lands, both functional and non-functional. Nevertheless, only an FEA analysis or testing can give a definitive answer. Werner Engelmaier Engelmaier Associates, Inc. Electronic Packaging, Interconnection and Reliability Consulting 23 Gunther Street Mendham, NJ 07945 USA Phone & Fax: 201-543-2747 E-Mail: [log in to unmask] *************************************************************************** * TechNet mail list is provided as a service by IPC using SmartList v3.05 * *************************************************************************** * To unsubscribe from this list at any time, send a message to: * * [log in to unmask] with <subject: unsubscribe> and no text. * ***************************************************************************