Electronics Forum | Fri Nov 09 15:52:47 EST 2007 | kmakiya
We have been using Grid Loks on our MPM Accuflex machines and see an offset in the print every so often. Haven't been able to isolate the problem. How bad was the misprint and how was it related to the grid loks? Thanks
Electronics Forum | Thu Nov 08 08:56:51 EST 2007 | hussman
Sorry Matt, Just hate when people use this site as their engineering bed. I believe you can weigh your board before and after reflow. It would have to be a sensitive scale though. From there you can calculate weight to volume ratios.
Electronics Forum | Thu Nov 08 10:14:43 EST 2007 | slthomas
"Their third attempt was a report that Process Engineering was being resistive and skewing the tests." Thanks for the early a.m. laugh. I needed it.
Electronics Forum | Thu Nov 08 13:00:33 EST 2007 | russ
Just how accurate do you need to be Matt? you seem to already know the answer, calculate the volume deposit from stencil aperture and divide x 2? that will get you very close wouldn't it? Russ
Electronics Forum | Thu Nov 08 14:24:17 EST 2007 | cyber_wolf
We are looking onto a taping machine. High mix high change over. Does anyone out there aside from the sales reps have any preference ? Good/bad/indifferent ?
Electronics Forum | Fri Nov 09 15:13:04 EST 2007 | mmjm_1099
WOW GOOGLE DOES WONDERS...... http://www.vtekusa.com/ http://www.qcorporation.com/ http://www.allproducts.com/machine/wisdom/showroom1.html PLENTY MORE OUT THERE.....
Electronics Forum | Fri Nov 09 10:46:24 EST 2007 | hussman
What is the real problem? No-solder can mean a variety of things. No-solder due to lack of paste? No wetting to the part? Co-planer part? Please specify......
Electronics Forum | Sat Nov 10 23:10:13 EST 2007 | mika
Hi Real Chunks, Nice to meet you. Well, I certainly not agree with you. Sorry. Can You be a little more specific about your claims, about my statements? Do you know what you are talking about? I wish no polemic about this. Best Regards, Mika
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 | Thu Nov 15 09:29:03 EST 2007 | jaimebc
Just to add to the subject, we experienced insufficient solder on our QFN's at our prototype level. To correct it, we went to a 5 mil stencil, 20% reduction on QFN pertures and used QFN's with solder bumps on the pads. We had great results using thi
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