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 Apr 09 12:52:00 EDT 2018 | slthomas
We are about to do a second iteration of something we struggled mightily with last time and I'm hoping to at least make a step in the right direction. There are 12 of these parts on the board and virtually all of them required removal and replacemen
Electronics Forum | Sat Mar 18 07:33:34 EST 2000 | Dave F
Jack: Two concerns with column devices: 1 Coplaniarity of the device and the board. 2 Adequate solder that you mentioned, becuase the columns will not be reflowing and you need to cloatthem with solder. You didn't describe your aperture, but even
Electronics Forum | Fri Dec 06 13:00:29 EST 2002 | daanterstegge
I wouldn't recommend a metal squeegee, because if you can't wipe the step-etched area completely clean (that's the problem with metal) you'll have problems with the definition of the fine-pitch (it may stick in the holes). Best is a 70 Shore polyuret
Electronics Forum | Tue Feb 12 14:00:53 EST 2013 | dyoungquist
We have a board with a 1.0mm pitch BGA. The stencil apertures are 0.0177 inch diameter. We used an electroform stencil with good results.
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 | Thu Sep 12 10:45:29 EDT 2002 | pbarton
We have used a laser cut stencil 0.15mm (0.006") thick with 0.3mm (0.012") square apertures radiused in the corners 0.06mm (0.0025") to aid paste release. This approach with the (type 3) paste we use has proven successful on thousands of devices plac
Electronics Forum | Thu Feb 08 08:28:11 EST 2007 | mzaboogie
Good Morning Everyone, We have an application coming up with several BGA's on a RoHS assembly. One is a 25 mil ball on a 40 mil pitch, another is a 15 mil ball on a 40 mil pitch. In the past for leaded assemblies, we have used square apertures for 1
Electronics Forum | Wed Mar 16 09:06:07 EST 2005 | russ
This is what I might do, I would purchase either a solder volume (preferred) or at the least a paste height measurement piece of equipmment, The most important parameters with pronting are volume and registration. You need one of these inspection
Electronics Forum | Fri Dec 17 15:26:48 EST 1999 | Victor Salazar
We use a homeplate design with 80% coverage on the tab, and 100% coverage on the leads 6mil stencil. All of our stencils are laser cut electropolished. We have had good success with this.
