Electronics Forum | Wed Jun 29 16:30:13 EDT 2005 | RICHM
.0025" under the part, all should be avoided
Electronics Forum | Thu Jun 23 11:56:51 EDT 2005 | wjxingggg
Hi, all. There is one 0.8mmX0.8mm QFN on almost of our PWBAs. But the quality report showed that we got bad solder quality for this component. My question is which elements are the root cause for this situation frequently? Thanks.
Electronics Forum | Thu Jun 23 17:59:02 EDT 2005 | davef
Jason: We'd like to help, but we don't know how to diagnose "bad solder quality". It's too broad of a complaint. Please be more descriptive, like: * Too much solder * Too little solder * Solder has too sharp of wetting angle
Electronics Forum | Thu Jun 23 22:30:31 EDT 2005 | wjxingggg
poor soldering of PCB. > unfit stencil hole of QFN > incoming problem for this component >...... What is your opinion? or what can I do for the next step? Thanks again.
Electronics Forum | Wed Jul 06 08:41:06 EDT 2005 | james
What I have seen too is that these parts normally come in a tube and from moving in the tube some of the copper starts to expose and solder will not adhere to these parts. Let me know if anyone else sees the same problem.
Electronics Forum | Wed Jul 06 12:25:55 EDT 2005 | HOSS
Bob, We have seen this same issue and haven't found a solution other than touching up to create a toe fillet. Luckily, it's a low volume product, for now. What have you done to combat this? Thanks.
Electronics Forum | Mon Jun 27 09:38:30 EDT 2005 | Bob R.
What problems are the quality people seeing? I hope they aren't expecting a toe fillet. QFNs are typically cut from an array after plating. This leaves exposed copper on the sides of the part. We'll often see smearing from the sawing process that
Electronics Forum | Wed Jul 06 12:04:39 EDT 2005 | sarag
Jason, If you have any pictures of this phenomena that might be helpful for the forum to see in helping diagnose your problem, you can send them to me and I can post them on my website to view. My email is sg_foresite@residues.com Sara Gorcos Fores
Electronics Forum | Fri Jul 15 13:58:32 EDT 2005 | seaK
Our production is putting QFN40 and QFN56 package on board. With 80% opening on terminal, 40% on thermal pad, we found QFN56 100% forming toe fillet, but it does not work out the same to QFN40. We suspect it's because of the weight of component.....
Electronics Forum | Fri Jun 24 07:02:35 EDT 2005 | davef
Problem 1: Solder shortage * Stencil aperatures [except the heat slug] should be 1:1 with the board. * Stencil should be 5 thou thick laser cut. * Board should be 1:1 with the component * Print should look good. Problem #2: Bad connection between p
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