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 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 | 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 | 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 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 | 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 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 | Wed Jun 26 08:53:32 EDT 2002 | davef
We have not done a DOE on board warping. Consider: * How close the board gets to its Tg during the reflow cycle * Amount of copper on each side and the balance between the two * Thickness of the board * Overall length x width * Time at temperature
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