Electronics Forum | Mon Sep 06 19:59:59 EDT 1999 | armin
| | | We've noticed that there are many different recommendations for pad sizes for various SMT parts. This seems to vary wildly from manufacturer to manufacturer for the same case sizes. Is there any standards that can used used to specify these s
Electronics Forum | Thu Nov 30 16:10:05 EST 2006 | Hussman
Wow, why all the anger? This gap you guys are talking about is measured as "G" in IPC/EIA J-STD-001 (Chunks was there, but she failed to read the fine print). And almost all parts that measure G follow Note 3 which states "Properly wetted fillet s
Electronics Forum | Thu Aug 13 14:10:01 EDT 2015 | markhoch
Hi Sam, I have a feeling that what you're trying to communicate is that your DPAK's are skewing off the pad during reflow. This is caused by a thermal "mismatch" where the solder paste on one side of the DPAK becomes molten before the other, then th
Electronics Forum | Wed Apr 13 21:17:18 EDT 2022 | stephendo
If it was ROHS, I would say that the pads are definitely dissolved away. And it sounds like that is the case here. Your best bet is if it is class 2 and the barrels are at least 50% then push for them to be accepted. If you are trying for more barr
Electronics Forum | Fri Aug 02 12:07:50 EDT 2002 | johnw
Richard, your asking a multi million dollar question that in my own opinion no one can give you the right answer since no one really knows. hence I think the lack of answers to your question....thought there would be more people willing to propose a
Electronics Forum | Tue Apr 10 02:57:53 EDT 2018 | rob
Yes I would, most of our old Yamaha machines (before 2005) will do 30-35 microns @ 3 sigma with the fine camera option. Our Jukis with His res camera's will hit it too. You should be OK with most things after 1997 with the right camera choice (whic
Electronics Forum | Wed Oct 21 08:06:06 EDT 2009 | scottp
I agree with Dave. If the device has a lot of power we'll put thermal vias between the solder deposits with annular rings of soldermask to keep solder out of the holes. We've never had to mess with placement pressure. We've been using QFNs for yea
Electronics Forum | Thu May 06 19:21:24 EDT 2021 | markhoch
Verify your aperture reductions in the stencil. Are the solderballs always in the same location? Same size & shape? Is the solder leaching through plated thermal holes from the opposite side of the PCB? Are you using stencil apertures designed to min
Electronics Forum | Tue Sep 23 23:19:34 EDT 2003 | RLW
If you have a board that you've run several times, now you run it and like before all settings are the same, but now you have 0603's randomly skewed or an inch or so away from their intended pad (as if popped up in the air), or an occasional 7343 cap
Electronics Forum | Thu Sep 07 03:57:39 EDT 2000 | Steven Cheung
Does anyone know of a freely-available document which discusses the main considerations of BGA assembly and inspection (x-ray?). l need to know about pad sizes and inspection standards and when to underfill and when not to etc.. l am looking at ass
