Electronics Forum | Tue Apr 10 10:21:06 EDT 2018 | slthomas
Dave, that's a cool idea and sounds like something that would actually work. I'd be tempted to go with oversized pads to increase the holding force. Unfortunately as an EMS we would have to work that through the customer approval system and as usual
Electronics Forum | Tue Apr 10 10:33:08 EDT 2018 | davef
Oh, I just remembered the other thing that I wanted to mention ... Do the pads match the component leads?
Electronics Forum | Mon Apr 16 16:24:20 EDT 2018 | slthomas
Amazingly enough, every one of these held fast where we placed them with a paste brick sized 1:1 with the thermal pad, no sectioning. Yes, there were voids, but we can live with that in this application.
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 | Wed Jul 18 17:09:45 EDT 2018 | slthomas
Update - next run started out horribly so went to another stencil design. Reduced thermal pad coverage by about 40% with 4 panes, with cutouts to avoid the vias. Worked like a charm for 10 boards (90 parts). I think we're finally on to something.
Electronics Forum | Mon Mar 20 10:54:36 EST 2000 | Glenn Robertson
Jack - The last time I checked IBM was specifying a minimum of 4800 cubic mils of paste for each pad. This is required for acceptable reliability, not just to make the connection. There is no way you are getting that volume with a 5 mil stencil
Electronics Forum | Tue Feb 04 09:03:45 EST 2003 | Russ Roberts
Greetings, I am pretty new to SMT production, and have learned much from this forum. I am getting ready to build a CCA with many 0402 parts that are really close together. I consider these fine pitch. The board also has two QFPS, so my stencil design
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 | 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 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
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