Electronics Forum | Thu Feb 24 06:09:26 EST 2000 | Robert Hutton-Squire
Hi, - any suggestions welcome... I have a 484 pin ALTERA fineline BGA - ball pitch 1mm (40) - ball size 0.48mm (18.9) What would you recommend for... 1. Surface pad size for the balls of this BGA device? 2. Stencil thickness/type and hole a
Electronics Forum | Tue Jun 27 11:16:33 EDT 2000 | Christopher Lampron
Hello Bill, Ioan's idea's are good. One more thing that you may want to consider is using a "Home Plate" aperture on your stencil for the aforementioned caps. The idea is to put a smaller amount of solder paste directly underneath the component. This
Electronics Forum | Thu Feb 24 06:09:26 EST 2000 | Robert Hutton-Squire
Hi, - any suggestions welcome... I have a 484 pin ALTERA fineline BGA - ball pitch 1mm (40) - ball size 0.48mm (18.9) What would you recommend for... 1. Surface pad size for the balls of this BGA device? 2. Stencil thickness/type and hole a
Electronics Forum | Thu May 10 15:48:12 EDT 2001 | kp
Good morning, We are presently using a couple surface mount parts on our circuit boards. We send the boards out of house to have the SMD parts placed. I have been told that the apertures for the stencil for each SMD are not to be 1:1 with
Electronics Forum | Thu Jul 19 09:56:52 EDT 2001 | Damian Holzmann
The obvious difference between 2D and 3D is that an accurate volumetric measurement can only be obtained with a 3D measuring system. Laser line measurement in 2D does not allow accurate volumetric measurement. If you modify the aperture in a stencil
Electronics Forum | Tue Jan 04 07:22:12 EST 2000 | Michael Selva
One of the boards has a via designed right in the middle of a pad for a 1206 cap, one side only. This causes the solder paste to run into the via during reflow. We run No-Clean paste. One alternative is to increase the aperture on the stencil for tha
Electronics Forum | Thu Sep 02 14:26:22 EDT 2004 | frankracine
Thanks Russ, very interesting. Are you working with a printer, PNP, reflow and wave? Did you change apertures in your stencils with lead free ? Concerning reflow, do you have a 5 zones, 7 zones ... ? Are you using the same alloys for solder paste
Electronics Forum | Fri Jul 15 13:16:08 EDT 2005 | Brian
We have seen this problem in the past and had to deal with similar customer constraints. It's not the flux causing the wetting, but the placement and pad geometries as some have mentioned. To reduce or eliminate the problem, we have changed the ape
Electronics Forum | Thu Nov 03 10:49:11 EST 2005 | russ
This is what I would propose, Place and reflow the board without the BGA with your lead process, remove the solder from the BGA pads if you cannot mask off the apertures in your stencil. Then place the BGA and reflow to SAC requirements with a rewo
Electronics Forum | Thu May 29 17:19:51 EDT 2008 | dyoungquist
On 0402s we use 20x25 mil pads with a 15 mil gap between the pads on the pcb with ENIG finish, 5 mil stencil with a 1:1 aperture (20x25 mil) and SAC305 lead free solder paste. We very rarely see any tombstoning on 0402s using this setup.
