Kevin gave you the number and the method but it is not a requirement. The requirement is form fit function. The standard says something like mounting the board in the assembly must not damage the assembly. You have a special case that the standard does not address. *** We are Moving - March 20, 2007 *** Guy Ramsey R&D Assembly 1660 East Race Street Allentown PA 18109-9580 (610) 264-1887 FAX (610) 264-1877 -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of McGlaughlin, Jeffrey A Sent: Thursday, March 08, 2007 7:05 AM To: [log in to unmask] Subject: [TN] Post Assembly Bow and Twist Technet and DesignersCouncil Gurus - I have been asked by our mechanical engineering group to find out if there is a standard or specification for post assembly flatness of printed circuit cards. This has never been an issue for functional failure but a new design requires that a row of LEDs mate to a display panel mask such that no light leaks from one LED cell to the next. Their concern is that post assembly bow and twist will over stress solder joints and board copper if they mechanically stress the cards by pressing/pulling them flat to an assembly frame. Can anyone direct me to a standard or advise me on the maximum allowable bow and twist for this type of situation? Jeffrey McGlaughlin, CID Engineering Designer Battelle 505 King Avenue Columbus Ohio 43201-2693 (614)424-7582 Phone (614)458-7582 Fax --------------------------------------------------- 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 ----------------------------------------------------- --------------------------------------------------- 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 -----------------------------------------------------