Electronics Forum | Wed Feb 22 10:00:58 EST 2006 | dougs
We've just set up a couple of products with 0.5mm pitch uBGA devices on them, i went for 5thou thick, laser cut nickel (to aid paste release) square pads same size as the diameter of the uBGA pads. Or you could go to a 4 thou nickel stencil, better
Electronics Forum | Tue Feb 04 22:28:16 EST 2003 | davef
You could reduce the paste by about 70%. Solder balling and tombstoning will be the issues to fight. The drivers to these don't change with the component size. Use the fine SMTnet Archives for background. Aperture Size and Thickness of Solder Pas
Electronics Forum | Mon May 15 19:59:45 EDT 2000 | Dave F
Doug: If the metal content of your NC paste is about 50% (by weight) there is no difference netween stencils for NC and other flux type pastes. And those are in the SMTnet archives. Good luck and happy searching Dave F
Electronics Forum | Tue Oct 22 10:23:38 EDT 2002 | davef
ubga and stencil
Electronics Forum | Mon Oct 21 23:48:13 EDT 2002 | harris
Hi: If anyone have the experience with the PCB pad design and stencil design for the uBGA? We meet the problem for it. The component data is 0.3mm diameter and 0.5 pitch. Could anyone tell me the PCB pad dimension, the stencil type and aperture dimes
Electronics Forum | Wed Oct 11 05:58:13 EDT 2023 | kojotssss
Hello all, I know there are very skilled guys. Can anyone suggest a stencil design to avoid component displacement during reflow to improve tension of surface forces and selfalignment? There are cases where the inductors are shifted. All parameters
Electronics Forum | Wed Oct 11 13:26:59 EDT 2023 | cyber_wolf
Its highly doubtful that stencil design will fix this. The Inductor floats during reflow and ends up going where it wants to go. The only way you are going to keep it in place is to put a dot of chipbonder beneath it or change the size of the lands
Electronics Forum | Wed Oct 11 18:30:21 EDT 2023 | kojotssss
Thanks for the opinions! You're right, it can't be solved with a stencil. I have made investigation, the problems are related to the quality of the component land surface, one of the terminal is oxidized.
Electronics Forum | Wed Oct 11 18:12:55 EDT 2023 | alexv
I don't think it's a stencil issue. You have an identical inductor next to t=it, that's perfectly straight. You have a problem in that location. I've seen some inductors be affected by slight magnetic forces in the reflow oven. Try to rotate the boar
Electronics Forum | Mon Nov 01 10:29:13 EDT 2010 | scottp
I've searched the archives and maybe my search skills aren't up to snuff but I couldn't find much. I'm curious what people are doing for 0.4 mm pitch BGAs, assuming a type 4 paste. Pad diameter? SMD or NSMD? Stencil thickness? Aperture diameter? Us
