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 | Sat May 27 11:13:27 EDT 2000 | Steve Thomas
Subject line pretty much says it all. We're going to try some stencil design changes to reduce midship solder balls. Anyone have some comments on pros or cons for either?
Electronics Forum | Sat May 27 12:50:21 EDT 2000 | Micah Newcomb
Steve, I use homebase apertures as a standard for all chip parts and have no complaints, no solder beading, no issues. I have had to replace almost all stencils ordered previous to my arrival as they all caused defects (7-9mil thickness and 1:1
Electronics Forum | Sun May 28 08:21:52 EDT 2000 | Sal
Can't agree more than moving over to Homebase apertures, But ensure that the cut back angle is correct,to acute of and angle will leave you with an inadequate contact area fot the terminations on the chip components and you will start seeing insuffic
Electronics Forum | Tue Oct 10 12:56:15 EDT 2000 | Ken Van ZIll
I agree that homplate is a good design, but also this could be caused by the stencil thickness and aperture size, if you are at 7-9 mils thick stencil and a 1:1 ratio on aperture size then 2 things i know of will happen, one a squishing out of past o
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
