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 | Wed Jun 26 21:05:15 EDT 2002 | ianchan
Hi Dave F, customer calls it "warp", we can call it "twist/bow"..etc. the "warp" occurs on individual PCB cells of 28per each panel. the overall dimension of the panel is 139mm x 168mm, and each individual PCB cell is 2.4mm x 1.2mm. Thickness is 0.
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
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 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 07:30:14 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 | 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
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