Electronics Forum | Thu Mar 15 18:15:28 EDT 2018 | maustin
The 740 has been a great machine for us. We've been able to reliably load components as small as 0603 (we've not tried 0402, but I believe with a special nozzle adaptor, you can get it to work) and place a 7x7 56 pin QFN with 0.4mm pin pitch with hi
Electronics Forum | Fri May 22 08:04:30 EDT 2009 | stevezeva
Have any of you ever worked with Actel's QFN 180? A three row I/O QFN? Actel has a published paper on design and assembly guidelines, but we're finding that they are pretty much generic, and don't really work as well as they lead you to believe. ht
Electronics Forum | Tue Jun 25 01:24:25 EDT 2019 | sssamw
That is possibley CTE mismatch between QFN and PCB material, the thicker PCB the higher fail rate.
Electronics Forum | Wed May 20 17:00:56 EDT 2009 | dyoungquist
We just placed a 56 pin QFN, 1 per board, on 10 boards and had zero defects. A good paste job, proper placement and a correct oven profile are the keys. If these are set up correctly, on larger runs your defects won't be zero but they should be le
Electronics Forum | Wed May 20 17:18:09 EDT 2009 | daxman
Just out of curiosity, how are you or anyone else determining a defect? Last I checked, IPC had no criteria yet for solder defects for QFN components. Has this changed? Biggest problems we see are voids which our x-ray shows a lot of. Our problems
Electronics Forum | Fri Apr 10 10:20:15 EDT 2020 | unisoft
Yes process engineers that work for contract manufacturers try to get the full CAD or XY rotation files from their clients unfortunately still many of their customers still give them only Gerber files for the PCB project. Unisoft has had a focus on
Electronics Forum | Tue May 12 10:03:12 EDT 2009 | daan_terstegge
Hi All, I see more and more components like QFN or LGA with bottom-only terminations,with landpatterns getting finer all the time. I have no ppm-figures of our process, but based on a benchmark study by Agilent I'd say that 500 ppm is a decent value
Electronics Forum | Wed May 20 17:56:51 EDT 2009 | dyoungquist
I have attached a pdf showing the dimensions for the QFN we placed. First, The pins on the part are not only on the bottom side but also wrap around to come up each of the 4 sides of the part as shown in the side view in the attached pdf. This i
Electronics Forum | Wed Jun 03 16:10:54 EDT 2009 | mattkehoe
Here is a little different spin on re-working/hand placing LGA's.. http://www.sipad.com/download/LGA%20Rework%20Document.pdf
Electronics Forum | Wed Apr 15 18:37:15 EDT 2020 | unisoft
The point here is if you can't get the full CAD files or the XY rotation files and all you get his Gerbers and a BOM. Most all contract manufacturers and some OEM's at some time or another have to deal with Gerber only files. If you find yourself i
