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 | 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 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 | 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 | Mon Nov 12 16:14:47 EST 2001 | davef
Yes!!! How can we assemble boards with 20 pitch when we allow 0.008� error to the master art? Excellent question!!! IPC-D-300G has nothing to do with assembler requirements. It is written by and for fabricators, so that they can be comfortable.
Electronics Forum | Mon Dec 19 12:21:09 EST 2005 | Amol Kane
from what i know, Tg is important from thermal stresses point of view. board warpage increases greately when Tg is exceed
Electronics Forum | Tue Jul 11 10:13:22 EDT 2006 | SWAG
Over time, you might see problems with delam., blistering and warpage if using FR4 carriers. Depending on volumes, you might consider using durostone or some robust material like that for the production runs. Keep in mind that switching materials w
Electronics Forum | Wed Aug 19 12:20:24 EDT 1998 | MARK J.
| 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 orde
Electronics Forum | Wed Aug 19 08:00:55 EDT 1998 | Earl Moon
| 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 orde
