Electronics Forum | Tue Oct 20 18:53:13 EDT 2009 | fdbittner
Having some issues with 56 contact TQFN. This is low-run prototype situation so no second chances - unfortunately. Part is 5mm X 11mm with .30X .63 perimeter lands and 2.5 X 8.5 thermal pad in center. Issues noted are intermittency at test (basica
Electronics Forum | Mon Mar 01 10:36:55 EST 2010 | patrickbruneel
Loco, Since Dave didn't respond i will. We shouldn't forget that even when using tin/lead solder the boards and components are still lead free. Parts that are not completely wetted by the tin/lead solder still have the potential for tin whiskering a
Electronics Forum | Thu May 20 18:14:53 EDT 2010 | geocep
Process Flux is AIM 275. Tip tinning flux is Superior 75. We have gotten dual nozzles in the 6mm & 9mm sizes we run. We can get a nozzle to run about 8 hours. Every night we clean all used nozzles with a scouring pad, apply Superior 75 flux with
Electronics Forum | Mon Mar 29 11:48:43 EDT 2010 | davef
SAC BGA In A Sn/Pb Reflow Process Conclusion: Area array components (ball grid arrays, chip scale packages, flip chip packages) with Pbfree solder sphere alloys should not be reflowed using a tin/lead reflow profile due to the resulting non-uniform s
Electronics Forum | Mon Apr 19 11:04:21 EDT 2010 | baildl632
We have had some unusual reflow conditions with BGA's as well. We did not come to the conclusion that something was covering the lands though. It typically occured with only the BGA lands (not the decoupling caps on the back side). We found that the
Electronics Forum | Wed Jul 07 11:02:07 EDT 2010 | davef
Rob gave you very good analysis and suggestions for troubleshooting your non-wetting issue. We agree with his sequence of troubleshooting. The following comments are meant to be a line to supplement Rob's plan of attack. This adds to Rob's comment
Electronics Forum | Fri Sep 17 03:13:00 EDT 2010 | grahamcooper22
In HASL pcb coating you need to fully coat the pads with solder and then blow off any excess solder to leave a nice coating on each pad. Generally pcb manufacturers try to give you a flat pcb pad to make your solder paste printing more consistent. To
Electronics Forum | Thu Sep 30 16:28:51 EDT 2010 | 18424
Hello All, looking for some help from you guru's. I have several Enig boards with solderability problems. Components ranging from 0402's to ssop's. Using AIM W/S leaded solder paste, profile is beautiful and has been for years running the same produc
Electronics Forum | Wed Jun 08 13:49:48 EDT 2011 | sonofptolemy
Hello, I am having a problem with HASL PCB's after it comes back from the stuffer. To me it looks like oxidation and it causes poor wetting. This leads to a bunch of problems all of which have different symptoms but the cause is this oxidation proble
Electronics Forum | Tue Oct 04 04:47:04 EDT 2011 | grahamcooper22
Having a selective solder machine without a preheat sounds ODD. Preheats are pretty important to drive off flux volatiles and activate the flux so it cleans the parts ready for the solder to wet to them. If you have no preheat then you must be expec
