Electronics Forum | Fri Dec 27 16:26:30 EST 2013 | davef
I expect to find the specification and measurement method for the bow & twist of an assembly to be on the assembly drawing. Comments are: * Expecting that an industry committee to write a bow & twist spec for an assembly they know nothing about is n
Electronics Forum | Thu Dec 26 12:12:55 EST 2013 | igorfo
Dear Friends, I need your help to understand requirements and measurement methods for bow and twist of assembled PCB (PCBA have and SMT and TH components). I already check all posts on the site but didn't found any related to my question answers.
Electronics Forum | Mon Apr 23 11:44:55 EDT 2001 | CAL
650 Standards are also located in the back of IPC JSTD-001. I am currently looking at 4 pages on bow and twist. Percent bow = R1-R2/L x 100 (R1= Highest point; R2=lowest or resting point; l= length) Percent twist=(R1-R2)/(2xL)x 100 Sorry if this is
Electronics Forum | Mon Apr 23 07:56:20 EDT 2001 | dougie
Hi Kris, DISCO!!!! Cheers, Dougie.
Electronics Forum | Mon Apr 23 14:36:16 EDT 2001 | CAL
Ah Yes.............My 600 A version has it in the back as well Cal
Electronics Forum | Fri Apr 20 07:12:22 EDT 2001 | wbu
Dougie, oh yes, it�s a bit short that chapter. I have the Revision e in front of me and this one contains in the appendix the needed IPC-TM-650 Test method for bow and twist. Can�t think that they don�t have that in the new revision. Hope you find
Electronics Forum | Mon Apr 23 14:03:18 EDT 2001 | Ryan Jennens
Dougie- We,too, have the IPC-A-600F, and the spec. refers to IPC-TM-650 test method in the back of the book. Look on page Number 2.4.22 of the test methods appendix. This outlines the procedure for determining the percentage of bow and twist,
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
