Electronics Forum | Wed Apr 05 23:56:02 EDT 2000 | angela
Recently we have serious problem of our 0.5mm pitch QFP solder bridge. I check the viscosity of the Litton Kester paster. It's roumd about 700 is it too low. And do you have god solution about it? thanks alot
Electronics Forum | Fri Feb 25 09:30:29 EST 2011 | kahrpr
Was the void on the same pad for the 5 failures or were they random
Electronics Forum | Mon Feb 28 23:07:04 EST 2011 | kemasta
It is random. By the way, this board pass thought wave process, (BGA is at the top), will that cause the older short issue?
Electronics Forum | Thu Apr 06 00:27:42 EDT 2000 | Dean
I would check their data sheet for the particular product. Thats the range I have for Some Kester products I use... Are you seeing any slumping prior to pick-and-place? Is the bridge in the same place every time? How is your pick-and-place mounting
Electronics Forum | Thu Apr 06 07:53:35 EDT 2000 | jacob lacourse
I have also come across this very same problem and found that our screen vendor made a mistake on our screen. Check the thickness of your screen it should be about six thousandths if it's eight thousandths then you are most likely depositing to much
Electronics Forum | Thu Feb 24 23:11:51 EST 2011 | kemasta
HI I have this BGA short issue, I took x-ray image, the solder ball having big void. We suspect the pad on BGA was oxidie. Reject percentage quite low, only 5 out of 6000. But after the BGA re-ball, is work fine. Anyone have any idea to trobleshoot
Electronics Forum | Thu Apr 06 08:31:13 EDT 2000 | D Scott
Angela Do you see this problem on other .5mm pitch devices or is it only on the QFP? Check placement height, too low or to high can cause you problems Pad co-planarity, are your boards HASL? Is your board sagging during placement(board supports) An
Electronics Forum | Thu Apr 06 02:23:50 EDT 2000 | Marcus
What about your printer and your stencil ? Do you have a problem with misalignment between pcb and stencil ? How often do you clean your stencil during production ? Maybe you have smearing under the stencil because there is a snapoff between stencil
Electronics Forum | Mon Dec 17 15:11:35 EST 2007 | chef
Blew chunks - thanx for thinking outside the box. Of course there's two sides to every story. Just last week I had a new operator "splash" a couple of boards. Top solder was great, it was all one big solder bridge. Come to find out, the operator forg
Electronics Forum | Mon Dec 17 21:11:13 EST 2007 | davef
Thanks bud. Merry Christmas and happy holidays to all.
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