Hi Andrea, Why are you interested in solder joint strength? A solder joint is basically in one of three possible conditions: (1) the solder joint is properly formed and all soldering surfaces are properly wetted and have formed a metallurgical bond between one of the solder constituents (typically tin) and a constituent of the soldering surface base metal (typically copper or nickel)--this solder joint requires great force to separate it (other than in fatigue), because metal has to be ripped apart and this solder joint has significantly more than adequate strength for even the most abusive handling and transport conditions; (2) the solder joint does not have a metallurgical bond to the base metal of one or both soldering surfaces (even though the solder joint may give a wetted visual appearance), either because those surfaces are not solderable (wrong material or contamination) or the soldering process was inadequate in terms of temperature and/or time)--this solder joint is held together only by weak mechanical adhesion and normal manufacturing, handling or transport conditions are adequate to cause separation and typically cause early (in-house) catastrophic failure; (3) the solder joint is only partially properly wetted--this solder joint will have adequate strength for normal manufacturing, handling or transport conditions, however vibration and/or mechanical shock, particularly at cold temperatures may cause failures; however, the solder joint strength will be significantly above case (2), because metal still will have to be fractured, but stress concentrations exist at the boundaries between wetted and non-wetted areas. The differences in solder joint strength in cases (1) and (3) do however have no influence on long-term solder joint reliability for the most prevalent cause of solder joint failure, thermal cyclic expansion mismatch fatigue. That damage mechanism is driven only by the loading conditions causing the fatigue and solder joint strength is not an important consideration. Thus the question: Why are you interested in solder joint strength? Also, because of the wide differences in the metals and geometries involved, there can not be any standards-- all measurements of pull strength will have to be relative. 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 is provided as a service by IPC using SmartList v3.05 * *************************************************************************** * To subscribe/unsubscribe send a message <to: [log in to unmask]> * * with <subject: subscribe/unsubscribe> and no text in the body. * *************************************************************************** * If you are having a problem with the IPC TechNet forum please contact * * Dmitriy Sklyar at 847-509-9700 ext. 311 or email at [log in to unmask] * ***************************************************************************