Electronics Forum | Fri Apr 20 13:55:09 EDT 2001 | kawiederhold
Hey Dougie, If you go to IPC.ORG and click on the on-line resources and databases, then on the "free downloads" link, the second or third document "for free" is the IPC-TM-650 in its entirety. It does discuss the test you are looking for! Have fun
Electronics Forum | Fri Apr 20 05:32:39 EDT 2001 | dougie
Hi, I've just splashed out �60 on IPC-A-600F trying to find out the formula for measuring the bow and twist of raw PCB's. Much to my dismay there are 10 lines on the subject in the whole standard. Worse still is that it tells me nothing I don't alre
Electronics Forum | Fri Apr 20 07:30:14 EDT 2001 | wbu
In short: the measured deviation / the length this deviation occurs * 100% = % of deviation Actually we encounter mostly "twist" so we put the board on a flat surface, hold it down at the corners to see if any of the corners lifts, measure the heig
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 | 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 | 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 | 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 Apr 07 20:16:23 EDT 2005 | davef
Q1) Simple way to measure the PCB warpage A1) IPC-TM-650; Method 2.4.22 Bow & Twist Q2) What is the maximum warpage can the SMT machine allow the to accept and place the component without problem. A2) That depends. IPC-A-610 Acceptability of Elect
Electronics Forum | Thu Sep 26 11:06:45 EDT 2002 | slthomas
Maybe you're well ahead of me, but make sure you search the archives for "bow" and "twist" as well as warp.....
Electronics Forum | Wed Dec 19 09:23:47 EST 2001 | davef
Bow & twist for bare boards and panels: IPC-A-610 1.5% for PTH only and 0.75% for SMT
