Hello,technetters! We perform double reflow on boards populated with SM LEDs on one side and on the other side SMCs and PTH connectors. In order to prevent the LEDs to go twice through hgh temperature profiles -the second one being even loger-we tried to use a solder paste with a lower melting point:Sn43Pb43Bi14 which is not eutectic. The cross section of the pin in hole showed some solder voids-which were present also when using Sn63 paste and are accptable from our point of view-but also cracks which originated from them along the pin or along the hole wall.Our boards are 0,1microns gold plated. Could anyone explain why it happed and give us some advice? Gaby P.S.Thanks to CONDOR and DAVE HILLMAN for their former replies! *************************************************************************** * 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. * *************************************************************************** * 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] * ***************************************************************************