Hi Phil, If you are getting warping, those parts will crack occasionally. Can you add a mechanical stiffener after SMT and wave to help prevent the bowing of the board? Also, if the parts are resistors, can you respin the board and put less vaues in series? Kerry McMullen Principal New Product Mfg. Engineer LTX Corporation 50 Rosemont Road Westwood, MA 02090-2306 (T) 781-467-5468 Phil Nutting <[log in to unmask]> Sent by: TechNet <[log in to unmask]> 01/31/2006 11:31 AM Please respond to TechNet E-Mail Forum <[log in to unmask]>; Please respond to Phil Nutting <[log in to unmask]> To [log in to unmask] cc Subject [TN] Large SMT physical failure prevention Good morning, We have some designs that are calling for large, 1825 and 2225 components. We have seen some mechanical failures where the parts have cracked. If we need to use these monster components, how do we ensure we reduce or eliminate the mechanical failures. Our failures were seen on a 16 inch by 17 inch 0.062 thick board. On these we have changed our handling methods. On smaller 2 inch by 2 inch boards is this a don't care? I know that rapid temperature ramp up or down in the reflow process could be a killer. Something to work out with our CM. Phil --------------------------------------------------- Technet Mail List provided as a 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/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 ----------------------------------------------------- --------------------------------------------------- Technet Mail List provided as a 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/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 -----------------------------------------------------