Food for thought: IF a board supplier can make an entire board the same size as your panel, and it meets the warp and twist spec for SMT, then why do they have difficulty with a board that has multiple images of a smaller board? I would hazard to think (and it IS a hazard) that the warp and twist spec would apply to the entire board, whether 1-up or multiple ups. Ask your board vendor, if they don't want to deliver a panelized board within spec, how could you trust them to deliver a single board, the same size, within spec? And don't accept an argument of "routing between the panels relieves stress so they warp easily." What if the single large board had multiple routes/cutouts? Either the board design needs to be examined for balance of design, or your vendor. Sounds like they may have lost control of their process somewhere. Sincerely, Roger M. Stoops, CID [log in to unmask] -----Original Message----- From: Marsico, James [mailto:[log in to unmask]] Sent: Thursday, March 14, 2002 7:49 AM To: [log in to unmask] Subject: [TN] Board Bow and Twist I think this is a no-brainer, but here goes... We were delivered boards in panel form from one of our suppliers. At Incoming Inspection, the panel was rejected for excessive bow (>75% for SMT) and returned the supplier. The supplier called me and said that even though the panel exceeded the bow requirement, the individual boards were acceptable. When I quoted the bow and twist requirement from IPC-6012, "Panels which contain multiple printed boards which are assembled on the panel and later separated shall be assessed in panel form." , he said yes, you measure the individual boards in the panel. I need clarification. Thanks, Jim Marsico Senior Engineer Production Engineering EDO Electronics Systems Group [log in to unmask] <mailto:[log in to unmask]> 631-595-5879 ---------------------------------------------------------------------------- ----- Technet Mail List provided as a free service by IPC using LISTSERV 1.8d 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 delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail 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 ---------------------------------------------------------------------------- ----- --------------------------------------------------------------------------------- Technet Mail List provided as a free service by IPC using LISTSERV 1.8d 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 delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail 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 ---------------------------------------------------------------------------------