Electronics Forum | Mon Feb 02 11:51:23 EST 2004 | prs
Hello, I'm working with Nelco 4000-13 material .031 thk and am experiencing some warping. the board is roughly 1" by 3" and the warping is in the long dimension. The grain on the panel is also in the long dimension. Any pointers or advice on contr
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 | Mon Feb 13 23:05:02 EST 2017 | swestheimer
I have been asked a very good question but have not been able to find a good answer. IPC for both PCB and PCBA refer to the X & Y dimensions to measure warp and twist but how would you determine the warp and twist for a round PCB or PCBA?
Electronics Forum | Tue Feb 14 22:20:10 EST 2017 | swestheimer
Hi Dave, Thank you for your inputs as they were good suggestions. I however let out one important detail and that this is IMS material and not glass reinforced so I think that there is more bending going on during processing than warping and twistin
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 | Tue Oct 12 10:24:50 EDT 1999 | Jose RG
Hi, We are in the way to evaluate different solder pastes, improve our solder paste incoming inspection steps, re-define our stencil requirements and the following questions are open. Two questions, 1- Is anybody using/requiring 1000 Kcps or more
Electronics Forum | Tue Mar 01 10:31:26 EST 2005 | Greg
QC --> Touch-up --> QC --> Assembly After SMT all PWB goes to QC, QC Inspects and marks all that needs rework then PWB's goes to Touch-up to fix what QC marked for rework. After that All reworked boards goes to QC for another verification and stampi
Electronics Forum | Thu Jul 27 21:34:41 EDT 2000 | Dave F
Gary: That's curious. Tell us more about your process steps, temperature profiles, paste, warping of the board without the PIH processing, components, etc
Electronics Forum | Tue Mar 19 17:30:46 EST 2002 | rculpepp
Does anyone have or know of any published guidelines for BGA layout on PWB's so that they can be tested. Specifically using micro vias? If anyone has any input regarding other test considerations for BGA devices I'd like to hear from you as well. W
Electronics Forum | Fri Jul 28 14:34:13 EDT 2000 | Gary Simbulan
Belive it or not, these boards were run through a Centech batch mode Vapor Phase machine. Single stage top side IR preheat. Vapor temp 218 C. Solder paste is an SN62 RMA.The boards were FR4 8 layer w/ solder mask, fairly conventional as might be e
