Electronics Forum | Thu Jun 28 17:05:46 EDT 2012 | davef
Here’s what we seem to know: * There’s a problem with voiding in the solder connections of SMT capacitors * A void is an open area caused by air or process fluid that is trapped within a solder connection * Voids are an allowable condition as long as
Electronics Forum | Wed Aug 23 08:05:50 EDT 2000 | Eugene Smelik
Dr. Lee: I have read that fillet lifting can be exacerbated by certain types of Pb-free solder. Can you explain which alloys cause this and why? Thanks! Gene Smelik Cookson Performance Solutions
Electronics Forum | Tue Mar 08 02:28:03 EST 2011 | nagesh
I have an issue with PLCC Insufficient Heel solder joint fillet.The aperture dimension is : 30 x 100 mils on PCB & on stencil also(1:1 per gerber).Rohs Process. My stencil thickness is 5mils due to presence of Tssop & QFP package & i cannot increase
Electronics Forum | Fri Jul 19 13:02:01 EDT 2019 | davef
Double-check me on this, but I don't believe that A-610 [IPC-A-610] requires side fillets on QFN solder connections, because the sides of most terminations are not plated. Plating on the bottom of the termination is sufficient for a proper solder con
Electronics Forum | Wed Mar 09 16:55:02 EST 2011 | davef
We agree with the previous poster. Open-up your aperture to increase the amount of solder paste. If you don't have a heel fillet, go home.
Electronics Forum | Fri Jul 19 13:09:55 EDT 2019 | edhare
Hi, Are you referring to the condition illustrated here? ... https://www.semlab.com/qfn-solder-fillets In this case, the solder was wicked down an attached un-filled PTH via. Ed Hare SEM Lab, Inc.
Electronics Forum | Tue Mar 08 09:29:52 EST 2011 | thanh
i don't see why it was insufficient. if you want more paste, i would increase by 10-15% aperture,and maybe double prints for printer.
Electronics Forum | Fri Jul 19 01:58:30 EDT 2019 | dhanish
May I know what is the requirement for side fillet for QFN?Any information from IPC spec on QFN side fillet?We cant make the solder joint form at the side fillet.
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)
