Electronics Forum | Sun Oct 28 08:32:47 EDT 2007 | davef
With a 7 thou stencil, we'd go 1 to 1. So for a more typical 6 thou stencil, we'd bump the aperture area by 1.15, maybe 1.2. We make no distinctions between 'innies' and 'outies'. Are you talking about castellations on land grid devices [ie, BCC�, L
Electronics Forum | Mon May 20 15:58:55 EDT 2013 | sevenzero
Did you try a thinner stencil? More pressure and speed in the printer? What size is the QFN? Maybe the aperture needs to have a + in the center?
Electronics Forum | Wed Nov 15 12:52:21 EST 2017 | georgetruitt
IMO – Look into nano-coatings for your stencil and radius all square apertures This should help out with solder paste releasing from the stencil helping with insufficient solder QFN LGA aperture design, try a stencil cut with a few different apertur
Electronics Forum | Mon Nov 12 09:13:50 EST 2007 | russ
Chunks is right, reduce center pad by 50% print the signal pads at 1:1. this will ensure you solder QFNs fine regardless of the actual part. If you are not printing then it is process capability issue and has nothing to do with QFN but rathjer small
Electronics Forum | Mon Jul 09 18:11:20 EDT 2012 | rsikora
Your selection of pads to use as Fids will be critical. In your pictures of the QFN component, the pcb pads are primarily non-solder mask defined, but on 3 sides of the QFN the corner pads become solder mask defined due to the copper ground flood.
Electronics Forum | Sat Nov 10 23:46:36 EST 2007 | mika
BTW, The surrounded QFN fine pitch terminals should have the normal aperture reduction of 7 % in case of RoHS Senju solder paste. This works for our Telecom customer. The vias in the ground pad will be somewhat filled with solder and makes it diffi
Electronics Forum | Thu May 05 20:08:59 EDT 2005 | Gene
We have My12 machines. The precision is 25mic. There is no problem with the accuracy. I assembled components 0201, QFN 20mils pitch /12 mils aperture, 0402 flip chips. Even if you have troubles with the video codes definition, mechanical centering co
Electronics Forum | Mon Nov 12 09:22:41 EST 2007 | devajj
BTW, The surrounded QFN fine pitch terminals > should have the normal aperture reduction of 7 % > in case of RoHS Senju solder paste. This works > for our Telecom customer. > > The vias in the > ground pad will be somewhat filled with solder >
Electronics Forum | Wed Apr 11 09:04:06 EDT 2018 | emeto
Try one aperture 60x60mil
Electronics Forum | Mon Sep 23 01:28:13 EDT 2019 | sssamw
Cannot understood your problem very clearly, please check IPC standard on QFN and its mfg process, also check the QFN supplier's recommendation, so can minimize the bridge.
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