Doug, I had an experience once with failing crystals in this package, but not due to soldering. Failure analysis by the component vendor showed internal physical damage to the crystal. Our only conclusion was that a reel may have been dropped by the operator damaging some of the components. The problem has not occurred again since then. Components of this type are somewhat sensitive to physical damage. This is just another failure mode you may want to consider. ========================= Bob Barr Manufacturing Engineering Formation, Inc. ========================= > -----Original Message----- > From: McCall,Doug [mailto:[log in to unmask]] > Sent: Wednesday, July 16, 2003 11:10 AM > To: [log in to unmask] > Subject: [TN] HC49 SMT Crystals and Reflow Soldering > > > Hi All > > Does anyone have any experience of HC49 crystals failing test > following > Reflow Soldering with a standard 183 Deg-C Eutectic solder > paste (Sn62 Pb36 > Ag2). > > - The max temp found at crystal is 225 Deg-C; > - Over 200 Deg-C is approx. 53 Seconds; > - The crystal is over 200 Deg-C for 22 Secs longer than the component > datasheet; > - Pre-heat is ramping up at 1.8 Deg-C per second; > - Time to 140 Deg-C is to long by 47 Seconds; > > The profile may have to be changed slightly, but any experience of > failing SMT crystals and failure modes would be appreciated as the > crystal spec apears to be very close to our profile parameters. > > Thanks. > > Regards, > > Douglas I McCall, > PCB Manufacturing Engineer - Eastbourne, --------------------------------------------------- Technet Mail List provided as a free service by IPC using LISTSERV 1.8e To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/html/forum.htm for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 -----------------------------------------------------