Electronics Forum | Thu Mar 22 15:44:50 EST 2001 | pteerink
I have a board with QFP240 plastic package exhibiting the same characteristics. Minimum heel fillet that doesn't change with stencil mods, paste change, profile change etc ( I am working to class 2, though, so my pass spec, although they are not pret
Electronics Forum | Thu Mar 22 15:45:20 EST 2001 | pteerink
I have a board with QFP240 plastic package exhibiting the same characteristics. Minimum heel fillet that doesn't change with stencil mods, paste change, profile change etc ( I am working to class 2, though, so mine pass spec, although they are not pr
Electronics Forum | Thu Mar 22 08:07:41 EST 2001 | CAL
Selective Laser Soldering? Beamworks and Speedline Electrovert Both demo'd units at APEX. I am partial to the Beamwork machine cause it was able to do BGAs. Are the QFPs acceptable? You mention cleaning the pads, Stencil aperture enlargement could t
Electronics Forum | Thu Mar 22 08:54:06 EST 2001 | dblsixes
I'm not familiar with Laser Soldering. I don't believe it to be a problem with the QFP themselves, since the two plastic parts are from different vendors in the same package. We also are having similar problems with other plastic parts on other boa
Electronics Forum | Thu Mar 22 13:41:41 EST 2001 | mparker
What's the reality of the situation? Are you creating a specmanship issue here just to satisfy Class 3? Can you demonstrate that the paste volume applied to the plastic QFP's give sufficient overall fillets for mechanical and electrical properties? W
Electronics Forum | Wed Mar 21 20:40:28 EST 2001 | dblsixes
We are building a monster ... Dimensions are 10" x 7" ... 12 layers ... A Logic Assembly with a Power Supply all rolled into one ... The Power Supply is in one section of the board, the logic in the other section ... The Power Supply obviously has a
Electronics Forum | Sat Feb 17 14:21:54 EST 2007 | Muhammad Haris
Hi All, I am using YV100Xg YAMAHA Pick and Place Mounter Machine and I am facing a tilting problem of PLCC 84 and QFP 240 pins ICs. I deeply checked about their vision files and place them on the double sided tape and found them ACCURATE on their pad
Electronics Forum | Fri Mar 23 18:55:30 EST 2001 | davef
Consider posting actual measurements of your pads, component leads, and apertures.
Electronics Forum | Thu Mar 22 16:06:22 EST 2001 | dblsixes
Our next plan of attack is to dog-bone the solder aperature. By reducing the width of the solder paste at the heel, we hope to slow the flow up the leg of the pin while the temperature of the pad catches up. We have boards that were HASL ...
Electronics Forum | Thu Mar 22 21:53:49 EST 2001 | davef
Don't mess with the doggie stuff until you get longer pads [and then you won't have to mess with it] because you'll just ruin your lead definition with more paste and still not have the heel fillet you desire.
