Electronics Forum | Thu Jul 22 06:54:45 EDT 1999 | Earl Moon
| | | I have pcb's in which i am experiencing warping. | | | the boards are 12.8125" on a diagonal measurement. | | | they are out approximatley .010". | | | the boards are combination thru-hole,smt, they also have 3ounce copper.what is acceptable,an
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 | 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 | Wed Jul 12 05:04:01 EDT 2000 | JohnW
Hi Guy's.... Was thinkng about i more this moning..in the shower actually...sometimes think I do my best work there!. So far I'm looking at stuff like integrating the DFM study to show thing's that are going to present production / process issues e
Electronics Forum | Wed Jul 21 13:12:11 EDT 1999 | John Thorup
| I have pcb's in which i am experiencing warping. | the boards are 12.8125" on a diagonal measurement. | they are out approximatley .010". | the boards are combination thru-hole,smt, they also have 3ounce copper.what is acceptable,and what is the pr
Electronics Forum | Tue Feb 25 10:32:09 EST 2003 | davef
I don't know the precise scheme, but it goes something like this ... WHAT TO DO * Use the general work instruction that applies to all boards. It goes into dimension and hole checking processes. It talks to visual instection of solder mask, solder
Electronics Forum | Wed Jan 29 14:22:56 EST 2003 | russ
Most bowing I see is caused by an asymetrical layer stackup of the PCB. (different copper thicknesses throughout the stackup) e.g. for a 4 layer board - 2 oz. copper on layer 1, 1 oz. copper on layer 4, etc... I would doubt that is the V-score since
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
Electronics Forum | Wed Oct 11 16:05:16 EDT 2000 | NLykus
Does anyone have any experience with running a double sided/surface mount(bottom)board manufactured with CHEM 1 material? We are currently looking at cost cuts. My personal experience recently in running a D.O.E. against other materials and solder
Electronics Forum | Fri Apr 16 13:15:17 EDT 1999 | Justin Medernach
| Hi, | I just cheesed my previous attempt at this. I looked through IPC 600 and couldn't find anything relating to dimensional stability of a board with regard to stretch. I found bow and twist but nothing on size. I have a PCB that is .030" over