Electronics Forum | Mon Feb 02 16:42:03 EST 2004 | davef
Bow & twist for bare boards and panels: IPC-A-610 1.5% for PTH only and 0.75% for SMT. So, what are you doing to these poor boards to make them warp?
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
Electronics Forum | Fri Jul 16 11:27:57 EDT 2010 | davef
Consider: * Bow & Twist IPC-TM-650; Method 2.4.22 * Previous threads on SMTnet, like: http://www.smtnet.com/Forums/Index.cfm?CFApp=1&Message_ID=54498
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 Feb 01 09:01:14 EST 2003 | davef
It sounds like your board is "dome shaped", some call it "cupped". If so, this is more of a twist than a bow. Before moving on, if we receive a board that is so torqued that we can't figure-out how to measure it, we reject it. Go back to your TM-
Electronics Forum | Wed Aug 11 18:35:17 EDT 2010 | julie1
Anyone work with or have knowledge about metal core/clad boards? The board I'm working with is approximately 2" X 3/4" aluminum core pcb, in a 56 up array. There are 3 LED placements per board. I'm having trouble getting a consistent screen print.
Electronics Forum | Thu Apr 07 10:58:01 EDT 2005 | Dhanish
Need help from the experts on 1)simple way to measure the PCB warpage 2)what is the maximum warpage can the SMT machine allow the to accept and place the component without problem. 3)I have seen some people are using 7mils/inch as a Warpage spec. a
Electronics Forum | Tue Jul 20 16:02:12 EDT 2010 | mikesewell
You may want to look at IPC 7721 Method 3.2 Bow and Twist Repair. In extreme cases you may need clamp or weight the pcb with bow in the other direction to yield a "flat" pcb in the unrestrained state. You will have to take the PCB up to or slightly
Electronics Forum | Mon Jun 14 14:30:42 EDT 1999 | Deon Nungaray
| | | | | Hello all! | | | | | Recently we got a problem about the Funtional test. Some boards passed tests by using the auto-fixture(vacuum), but failed by using manual test fixture(need to plug CPU, DIMM etc.). The error symptom is no picture. We d
Electronics Forum | Tue Nov 16 18:02:29 EST 1999 | John Holland
What are the main advantages of moving from a 140 degree C FR4 laminate to a higher Tg laminate 180 degree C ?. Would the higher Tg laminate be less susceptable to bow and twist ?. John Holland
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