Electronics Forum | Thu Dec 29 14:06:38 EST 2005 | elias67
James, The problem is probably the result of a low quality thin walled frame. The company that originally came up with this design uses a 1/8 " wall frame. This frame does not bow at the standard 40 Ncm tension. There are thinner walled "knock off
Electronics Forum | Wed Apr 19 20:33:14 EDT 2006 | davef
I just flew in from (insert city) and boy are my arms tired. pr: Likely, you're correct. The "pound-inch" units should have been the give-away, for us. Good catch. If this is the case, the frame fabricator would be the best source for tensioning
Electronics Forum | Sat Nov 18 21:20:58 EST 2006 | Fer
Dave, May I ask where did you find the 1.5%, or the goal of .005" (or .007") per inch? The IPC-A-600 bow and twist standard calls for a .75% based on the calculation of the test method TM-650, method 2.4.22, which calculates the percentage based on
Electronics Forum | Thu Feb 27 12:27:10 EST 2003 | stevel
Hi all, We got some bare pwb in our incoming inspecion looked really wrapped. The maximum twist of the pwb we messured is 0.056inch by following the method in IPC-TM-650 2.4.22 C. (The diagonal size of our pwb is 7.5inch) According to the IPC standa
Electronics Forum | Fri Feb 28 09:08:03 EST 2003 | davef
Without drilling through the numbers, they're probably correct. Recognize that standard warp / twist specs [IPC-A-610 1.5% for PTH only and 0.75% for SMT] are not going to make it on tech boards. You need to define specific requirements. This warp
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 | Thu Aug 09 07:53:16 EDT 2012 | davef
Allowable bow & twist: Together, both IPC-A-600G and IPC-6012B represent the core IPC documents for describing the acceptable and nonconforming conditions that are either externally or internally visible on finished printed boards. IPC-A-600G relies
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 | Wed Aug 19 05:00:56 EDT 1998 | Tom Blum
Hi there, I'm actually facing a lot of trouble with PCB's presenting up to 3mm of bow /twist at reception i.e. before assembly. The PCB size is 220 by 230mm. The boards are to be assembeled SMD double sides with 05.mm pitch on both sides. In order to
Electronics Forum | Sat Nov 18 08:42:11 EST 2006 | davef
Bow & twist: IPC-A-600. Acceptability of Printed Boards 1.5%; Goal 0.005" per inch; Practicle 0.007" per inch
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