Electronics Forum | Wed Aug 23 15:10:24 EDT 2000 | Dr. Ning-Cheng Lee
Fillet lifting is a phenomenon mostly observed at wave soldering. It is caused by mismatch in thermal expansion coefficient (TCE) between solder and parts, and aggravated by the pasty range of solder alloys. Upon cooling, the mismatch in TCE will cau
Electronics Forum | Mon Jul 22 02:13:31 EDT 2019 | jandon
some PQFN package configurations have no toe exposed or do not have a continous solderable surface on the exposed toe and a toe fillet will not form. (IPC-A-610F 8.3.13)
Electronics Forum | Tue Oct 02 12:56:41 EDT 2001 | Scott B
We have come across this where the operator was using thin gauge solder wire (more suited to fine pitch SMT soldering) to form large solder fillets (power connections or sheild cans). We found that the operator was feeding large amounts of solder wir
Electronics Forum | Fri Sep 20 17:43:03 EDT 2019 | deanm
Looks like poor wetting/solderability to me. I don’t see heel fillets on the leads where the solder balls up. The solder has to go somewhere. It won’t flow where it won’t wet. Try printing a bare board and run through reflow. If the solder balls up o
Electronics Forum | Mon Jul 16 09:04:00 EDT 2001 | Hussman
No argument here. But I've don't think I've ever seen solder balls on 0402s. Even when they're placed on narrow G dimension pads, where there is little toe fillet, I've never seen a solder ball. But your idea of reversed homeplates would work grea
Electronics Forum | Fri Jun 12 11:15:50 EDT 1998 | Ryan Jennens
Hey all! The wave solder warrior is back. I have found a flux which leave almost no residue (the least yet), but because of its super low solids content I absolutely cannot get topside fillets. The multi-layer, two sided board is on a pallet w
Electronics Forum | Tue Jul 17 15:13:53 EDT 2001 | mparker
Dave - I agree that the U shape for QFP's sounds a bit whacked, for the reasons you state. It may work OK for larger pitchs but then again there are a myriad of fixes that work before resorting to U shapes. With the U shape removing paste from under
Electronics Forum | Wed Jan 15 21:55:41 EST 2014 | padawanlinuxero
we do that and there's a variation on the solder temp. sometimes around 10 degrees, we have 2 solder pallets that are run in intervals of roughly 3 1/2 minutes a part (the time that take the operator to put all 3 terminals in a 42 pcbs per board, and
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