You would have to inspect a board right after it comes out of the placement machine to see if paste is pushed out or there is any smearing. Much of the small variances are gone after reflow. A second inspection after reflow would establish whether there is a problem or not. However if the setup of the bottom supports is not being done exactly the same way from one setup to another you could be looking at a marginal problem that was occurring that day but could be worse on other runs. A good process must be repeatable and that starts with setup. In general the bottom supports should have been in place to prevent deflection and board bounce that can effect the alignment of other parts that were placed earlier in the placement sequence, especially MELF (round bodied parts), tall narrow SMT connectors. John Goulet Process/MFG Engineer ----- Original Message ----- From: "Dale L CTR USAF AFMC AFRL/RXSA Hart" <[log in to unmask]> To: [log in to unmask] Sent: Monday, October 4, 2010 2:26:04 PM Subject: [TN] pick and place /board deflection I was on the shop floor and noticed deflection in the 8x8 inch panel that was being populated. Would the deflection in the middle of the panel cause components to sit higher on the paste and thus have a slightly higher solder joint height than components on boards along the rails? Thanks in advance Dale L. Hart Universal Technology Corporation (UTC) Failure Analysis 1270 North Fairfield Road Dayton, Ohio 45432-2600 (937) 656-9165 Fax (937) 656-4600 Email: <mailto:[log in to unmask]> [log in to unmask] --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 15.0 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 ----------------------------------------------------- ______________________________________________________________________ This email has been scanned by the MessageLabs Email Security System. For more information please contact helpdesk at x2960 or [log in to unmask] ______________________________________________________________________ --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 15.0 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 -----------------------------------------------------