Hi Carey, SOT-23's have leads made of Alloy 42 (42% nickel & iron). This material is more difficult to solder to than are Cu alloys; everything else being equal it needs to reach about 15C hotter during peak reflow or be at a lower temperature for a longer time. As Dave indicates, slowing down the conveyor in the reflow machine is a way of getting more heat to them; I prefer in most cases to raise the set point in the peak reflow zone. But it really depends on the mix of the components on the PWA which way to go or whether to raise the set point some and slow down the conveyor. You should really measure the reflow temperature profiles by instrumenting key locations on one assembly with thermocouples. 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. * *************************************************************************** * 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] * ***************************************************************************