(1) At normal component spacings, neighboring components should not significantly affect each others solder joint temperatures--the conductive heat transfer between component and PWB becomes good only after solder joint formation. However, for operating use, it is my understanding that Boeing places the components on the PWAs for commercial aircraft with uniform operating temperatures in mind. (2) Modern reflow ovens provide good temperature uniformity, and certainly experiments need not be done for uniformity. However, profiles need to be established for each code to assure that even the slowest heating solder joint on the most massive component will be about 20C above liquidus for 5 to 10 seconds. 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. * ***************************************************************************