Hi Rich, First you should look at the work reported in IPC-TR-484, "Round Robin Reliability Evaluation of Small Diameter Plated Through Holes in Printed Wiring Boards," then you should examine Appendix B of IPC-D-279, "Design Guidelines for Reliable Surface Mount Technology Printed Board Assemblies," and the quickest way to get on board of current thinking on this subject matter you may want to take the workshop "Design, Manufacturing and Reliability Issues of Small-Diameter/High-Aspect-Ratio Plated-Through-Holes and Vias" given this coming Sunday at IPCWorks'97. 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] ############################################################## TechNet Mail List provided as a free service by IPC using LISTSERV 1.8c ############################################################## To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body: To subscribe: SUBSCRIBE TECHNET <your full name> To unsubscribe: SIGNOFF TECHNET ############################################################## Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information. For the technical support contact Dmitriy Sklyar at [log in to unmask] or 847-509-9700 ext.311 ##############################################################