Electronics Forum | Thu Aug 05 09:09:01 EDT 2004 | Kris
is QFP lead co plnarity an issue ? If the QFPS are not sitting in the paste and that can be random if they are very close to the manufacturing tolerence Thx
Electronics Forum | Thu Jul 29 21:19:09 EDT 2004 | davef
You need: * Solder that is active enough to made those leads take solder * Reflow recipe that makes the most of the flux is the paste The flux in neither of your solder pastes is getting done.
Electronics Forum | Fri Jul 23 09:17:16 EDT 2004 | davef
The more we think about this, the more we think you should join the 20th century and upgrade from your good ol' WS609. We know this will be tough. We used the stuff for 10s of years.
Electronics Forum | Fri Jul 23 20:59:34 EDT 2004 | KEN
Ahmen bro. About 6 years ago I sent 12,000 dollars of this paste to the recycler because I calculated the cost of direct manufacturing defects would outweigh the cost of the paste!
Electronics Forum | Mon Jul 19 08:55:54 EDT 2004 | dwanzek
Thanks, good input. The joints do seem to wet well, they pass solderability test we have done. The defect is apparent right after reflow, before wave solder. No we do not profiled with the oven loaded..... good idea. We run an ovenrider each shift an
Electronics Forum | Mon Jul 19 19:39:06 EDT 2004 | KEN
I once had a forced convection oven (insert brand here)...and the top 220VAC heater (reflow zone) had shorted to the frame ground, blowing the branch line fuses. THe machine had no idea the heater was out because the lower heater was heating the upp
Electronics Forum | Tue Jul 27 11:32:20 EDT 2004 | dwanzek
Thanks for the input guys. One problem with this theory, we see the same failure using Omni 5000 solder paste. We also see this problem across 4 production lines, suggesting it is not oven related. The profile meets recomendations and we have tried
Electronics Forum | Thu Jul 15 22:03:07 EDT 2004 | KEN
In no particular order: Will the failed joints wet when touched with an iron + flux? Is there flux surrounding the joint (post reflow). If no, you may be baking it out premateurely. Is this assembly wave soldered? Where is defect discovered in yo
Electronics Forum | Thu Aug 05 05:23:13 EDT 2004 | Bryan
Hi All,per my understanding ,the fail mode is the heel fillet of QFP seems no good,right?If yes...I think..we should:1.increase the aperture length on stencil and make sure there's enough solder paste on pad before reflow. or you can increase your t
Electronics Forum | Thu Jul 15 18:07:04 EDT 2004 | dwanzek
This has been a tough one to date. Any ideas will help. Problem definition � random QFP144 part not soldering all leads. Percentage fallout is about 1-5% of boards. Usually leads, one or more, on trailing side to the direction of travel does not wet
