Electronics Forum | Mon Feb 13 23:05:02 EST 2017 | swestheimer
I have been asked a very good question but have not been able to find a good answer. IPC for both PCB and PCBA refer to the X & Y dimensions to measure warp and twist but how would you determine the warp and twist for a round PCB or PCBA?
Electronics Forum | Tue Feb 14 22:20:10 EST 2017 | swestheimer
Hi Dave, Thank you for your inputs as they were good suggestions. I however let out one important detail and that this is IMS material and not glass reinforced so I think that there is more bending going on during processing than warping and twistin
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 | 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 | 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 | 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