Electronics Forum | Wed Jul 01 13:17:39 EDT 2015 | davef
Cheryl Tulkoff and Randy Schueller do a good job summarizing the thinks on pad cratering here: http://www.smta.org/chapters/files/uppermidwest_padcratering.pdf Potential Mitigations to Pad Cratering * Board Redesign * Solder mask defined vs. non-s
Electronics Forum | Mon Dec 18 11:17:52 EST 2006 | mashmo
I am always looking for ways to make my boards more reliable and easier to fabricate and assemble. I have been baselining my footprints off of IPC-7351 and with the latest revision of the calculator they have started a new feature. Normally on say
Electronics Forum | Mon May 14 14:51:36 EDT 2001 | Brian W.
Personally, I prefer the OSP. I get a flat surface to deposit paste on, resulting in more consistent solder paste volumes. With HASL, the amount of plating and the mounding affect the paste deposition. I have even had it affect the placement. The
Electronics Forum | Sat May 12 00:04:36 EDT 2001 | zam_bri
The product I'm running currently consist a mix of 20 mil pitch QFP, 50 mil pitch, 0402, BGA and variable size of connectors from small to big, on OSP finished PCB. Running intrusive reflow with a mix packages is a real headache, esplly when you hav
Electronics Forum | Mon May 14 17:12:20 EDT 2001 | davef
Continuing along the path that Brian took ... IPC-7525 gives design guideline for stepped stencils. It goes something like: * Stepped area SB GT 25 thou from pads located on the greatest thickness of the stencil * Pads in stepped area SB GT 35 tho
Electronics Forum | Fri Dec 27 14:27:40 EST 2019 | slthomas
We switched to a REL0 T3 paste, Amtech LF-4300. It wets the castellations more consistently. I believe that in our case it was more of a plating wetting issue with the parts, but yours sounds more like a pcb finish or thermal issue. That larger pad
Electronics Forum | Wed Mar 20 19:10:43 EST 2002 | rmerk
I would like to know if there are any detailed studies or sources of information regarding the use of round pads vs square pads with chip components (0402 and greater).Thank you.
Electronics Forum | Tue May 09 18:30:35 EDT 2006 | muse95
I can understand the theory behind fewer tombstones with SAC. If people were having tombstone problems with SnPb eutectic solder, often switching to Sn62Pb36Ag2 would improve it, because with the addition of some silver, a small plastic zone in the
Electronics Forum | Wed May 10 08:41:19 EDT 2006 | russ
Yes, we added some soak, we also use a 5 zone oven. We utilize a .020" x .020" pad with center to center at .042". We only get tombstones on misplacement or bad paste release now. Registration of component is key with pbfree, the parts just don't s
Electronics Forum | Tue Sep 12 10:55:29 EDT 2006 | slthomas
I found this searching the archives. Unfortunately Bob doesn't seem to have an active site anymore, just references by people he works for. It's a shame, because there was a load of good stuff there. Haven't looked at Phil's site for a while but it's
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