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 | Thu Apr 23 07:34:15 EDT 2020 | stephendo
Stencil editing is something that you have to do to do well. And you have to look at the boards after the screen printer and after the oven. Reading white papers ain't gonna cut it. And then there will always be part pad combos that will introduce s
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 | 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 | Thu Nov 01 13:08:33 EST 2001 | dave231
I am just starting to get into sub 50mil pitch, but from what I can see you are correct. But I can help with solder stencil. I cut the width only half of what the pad is, but the keep the length the same. This has helped but does not fix always. Stil
Electronics Forum | Thu Mar 19 16:13:28 EDT 2020 | stephendo
I tend to go by extending it by a distance rather than a per centage. For example 10 thou over. Does anyone else give a distance rather than a per centage? For long pads on connectors where I need more solder, a per cent doesn't make sense to me.
Electronics Forum | Fri Oct 18 09:50:02 EDT 2002 | russ
Steve, I am not aware of any standards so to speak. But IPC 782 and 770 have some useful info regarding mounting and pad geometries for wave etc... Since I do not know what type of components you will be wave soldering I will just give you some
Electronics Forum | Tue Oct 30 08:48:01 EST 2001 | dougie
Hi, Our PCB designers are beginning to send up designs to manufacturing that have increasingly difficult footprints to work with. The footprints have been generated by the IPC-SM-782 calculator but just look wrong to me. The pitch of the devices in
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 16 09:58:55 EDT 2007 | davef
"Although some lead-free pastes performed adequately and newer pastes work better than earlier formulations, this detailed experiment confirmed that tin/lead solder pastes wet back to PCB pads better than lead-free solder pastes. Therefore, a more ac
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