Electronics Forum | Mon Mar 03 11:07:40 EST 2003 | MA/NY DDave
Hi In addition to what DaveF gave you which you should look at first Search the archives for warp bow twist warpage etc. A Lot of treads exist. Many of the larger OEM's and even the Mil have historically created their own documents for acceptable
Electronics Forum | Mon Feb 02 16:42:03 EST 2004 | davef
Bow & twist for bare boards and panels: IPC-A-610 1.5% for PTH only and 0.75% for SMT. So, what are you doing to these poor boards to make them warp?
Electronics Forum | Thu Oct 14 20:42:07 EDT 1999 | Jeff Ferry
Grace, As deifned in IPC 7721 Procedure 3.2 Bow and Twist Repair "Bow and twist after soldering shall not exceed 1.5% for through hole PC boards and .75% for surface mount PC boards. The bow and twist shall not be sufficient to cause difficulties d
Electronics Forum | Thu Aug 09 07:53:16 EDT 2012 | davef
Allowable bow & twist: Together, both IPC-A-600G and IPC-6012B represent the core IPC documents for describing the acceptable and nonconforming conditions that are either externally or internally visible on finished printed boards. IPC-A-600G relies
Electronics Forum | Thu Dec 12 15:34:59 EST 2002 | msimkin
Has anyone had any expereince with FR4 boards under the std 0.5% warpage for Bow & twist with CSP & uBGA devices on them that have caused failures. Are there any revised percentages for boards loaded with these devices that anyone knows of, istead of
Electronics Forum | Tue Aug 10 09:01:18 EDT 2010 | davef
No, warpage tells you that design and/or fabrication process and/or assembly process need[s] to be corrected. Here's a link to a recent thread on SMTnet that seems to answer some of your questions: http://www.smtnet.com/Forums/Index.cfm?CFApp=1&Mess
Electronics Forum | Tue Feb 14 09:10:43 EST 2017 | davef
Assuming the traces run parallel and perpendicular to each other, I'd choose one direction the traces run as "x" and the other direction for "y." Then I'd pick a unique identifier on the board to insure proper orientation. Next, I'd measure warp and
Electronics Forum | Mon Mar 03 10:31:57 EST 2003 | Tim Nicholson
Is there any standards for board warpage for surface mount boards?
Electronics Forum | Mon Mar 03 10:49:12 EST 2003 | davef
Look here: http://www.smtnet.com/Forums/index.cfm?fuseaction=view_thread&CFApp=1&Thread_ID=5943&mc=2
Electronics Forum | Mon Feb 02 11:51:23 EST 2004 | prs
Hello, I'm working with Nelco 4000-13 material .031 thk and am experiencing some warping. the board is roughly 1" by 3" and the warping is in the long dimension. The grain on the panel is also in the long dimension. Any pointers or advice on contr
