Electronics Forum | Fri Dec 01 13:30:08 EST 2017 | kojotssss
Stencil thickness is 4 mil. Via's are plugging from bottom. Gas may be developed under the component? Take Reflow Ovens Thermal Profiling changes? In your opinion?
Electronics Forum | Thu Oct 01 06:44:44 EDT 1998 | PARK KYUNG SAM
Are there anyone who can give me the answer about solder ball problem? We have 12 layer PCB and double sided PCB. After one side reflow soldering We found lots of solder ball under the PCB. The solder ball was coming out from via hole. So when w
Electronics Forum | Thu Aug 10 07:29:43 EDT 2017 | stivais
How do you evaluate the soldering quality for those QFNs? X-Ray or AOI? For some QFNs (and other bottom termination components) it's not supposed to have solder fillets on toes. It's also noted in IPC-A-610 (Rev.F 8.3.13). Take a look at your QFN ch
Electronics Forum | Sat Jun 05 13:38:22 EDT 2021 | ppcbs
For Linear Tech LGA's we solder bump the LGA using a .30mm solder ball then reflow with a tacky flux. This will provide a void free solder joint and adds a little height to the solder joint in case you use a flux that you want to clean from under th
Electronics Forum | Thu Jun 24 11:54:36 EDT 2004 | rickw
many solder-ball issues can be resolved by reducing the aperture size, usually 10 to 15% reduction will work. If the aperture size is the same as the pad size paste tends to be squished out under the part, paste off pad under the part will liquify a
Electronics Forum | Fri Jun 17 23:31:12 EDT 2005 | kenscj
Hi all, currently, we are seeing BGA problem like solder ball misalign, void, solder short (all under BGA, tested with 5DX), after reflow. We examine the solder ball (raw material of BGA), and see that the ball surface is not smooth, will that affe
Electronics Forum | Thu Mar 30 08:38:58 EST 2006 | Dan
We have this panel that is Gold Flash. Am I correct in assuming this is technically a lead-free panel then? We are running a WS paste, and the QFN28 has balls of solder instead of a fillet. My Max temp is 216, and the TAL was between 52-57 secs with
Electronics Forum | Thu Aug 08 16:41:18 EDT 2002 | davef
On our last thing like that [5X5, 32, er 28?], we printed bumps on the QFN, but you can't do that, so there's no sense in tormenting you. Ideas that come to mind are: * Search around SMTnet for a paper by Chrys Shea on controlling dispense shots as
Electronics Forum | Thu Aug 23 16:28:14 EDT 2007 | grics
I want to get a collective opinion from the forum... I was always under the impression that Humidity at SMT can be a disaster and can cause solder balls... But what about at the Wave/Selective solder? If every board or almost every board has solder
Electronics Forum | Mon Mar 25 21:50:10 EST 2002 | davef
Some of this was copped from Fred. There are numerous package types that now fall under the rubric of land grid array [LGA]. Land grid devices [ie, Bumped Chip Carrier� [BCC], LGA, Quad Flat-pack No-lead [QFN], MicroLeadFrame�, etc] are essentially
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