Hi Ronan, Voids can,temporarily, retard crack propagation in their vicinity. The best work on this subject was done by Charles Schmidt at SRI. However, the effect is small enough and too localized to have a measurable efect on cyclic life. Voids can however reduce the heat transfer function in solder joints placed for thermal reasons. Werner Engelmaier Engelmaier Associates, L.C. Electronic Packaging, Interconnection and Reliability Consulting 23 Gunther Street In December: Jasmine Run Mendham, NJ 07945 Ormond Beach, FL 32174 USA Phone & Fax: 973-543-2747 Phone: 904-437-8747, Fax: 904-437-8737 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 ##############################################################