Electronics Forum | Wed Jun 26 08:53:32 EDT 2002 | davef
We have not done a DOE on board warping. Consider: * How close the board gets to its Tg during the reflow cycle * Amount of copper on each side and the balance between the two * Thickness of the board * Overall length x width * Time at temperature
Electronics Forum | Wed Dec 27 21:12:30 EST 2000 | Dave F
From a process perspective, I don�t know if you should be concerned ... You've told us nothing about your process. THE BOOK JEDEC MO-51 allows 6 thou warp in smaller [1mm pitch] BGA and 8 thou in larger [ 1.27mm and 1.5mm pitch] BGA. The increase
Electronics Forum | Mon Mar 13 22:29:50 EST 2006 | davef
Warp depends on: * How close the board gets to its Tg during the reflow cycle (the closer you get to the Tg the worse the warp gets) * Amount of copper on each side and the balance between the two * Thickness of the board * Overall length x width * T
Electronics Forum | Mon Oct 03 22:12:53 EDT 2005 | davef
When we see warp and twist, we usually jump the fabricator for: * MLB construction (not homogeneous or unbalanced - too resin rich or poor) * Supplier process capabilities (lamination cycles) * Material selection (usually cheap and dirty), etc. War
Electronics Forum | Tue Aug 08 20:43:41 EDT 2000 | Dave F
Tom: So is warp or is it twist? They�re different problems, possibly with different sources!!! And possibly different solutions!!! Consultants to talk to are: Earl Moon (pod@vcn.com), Werner Engelmeyer (engelmaier@aol.com), Les Hymes (les.hymes@w
Electronics Forum | Fri Oct 15 11:05:50 EDT 1999 | Mark Phinney
Earliar we had problems with board warpage, Much of our problem was due to imbalances in the copper on oppisite layers in brief on a 8 layer board the copper on layer 1 should = the copper on layer 8, 2=7, 3=6, 4 = 5. We added copper to some layers t
Electronics Forum | Mon Dec 31 08:51:58 EST 2001 | davef
Warp depends on: * How close the board gets to its Tg during the solder cycle (the closer you get to the Tg the worse the warp gets) * Amount of copper on each side and the balance between the two * Thickness of the board * Overall length x width * T
Electronics Forum | Mon Oct 31 19:37:16 EDT 2022 | emeto
Just because you can't add copper to the board, doesn't mean you can't add copper to the panel. Redesign panel, where board house can add copper to the panel to balance the board a little better. I would advise against low melting solder alloys on cu
Electronics Forum | Thu Oct 13 15:38:18 EDT 2022 | proceng1
Do you have the ability to add copper thieving or otherwise balance the design? We had a customer making LED boards with a terible inbalance. Some of the boards would "smile" so badly in the oven that the leading edge touched the top. They switche
Electronics Forum | Fri Feb 27 10:54:38 EST 1998 | Earl Moon
REVISITING MULTILAYER DIMENSIONAL STABILITY AND LAMINATE INTEGRITY It has been said we must learn it all over again and again about every four years. I know Lee Ritchey said that to me about high speed digital circuit design. The same seems true for
