Electronics Forum | Thu Jul 31 15:41:23 EDT 2003 | davef
Q: Could any of you guys tell me what exactly is this greenish thing ? A: No, but is not copper oxide. Copper oxide is brown, the color of a penny [here in the US] or an untreated copper laminated trace on a board. Many copper salts are greenish in
Electronics Forum | Wed Jul 29 10:46:04 EDT 2009 | babe7362000
I was wondering if anyone knows the best way to clean oxides off of fine pitch components? Apparently the paste we use does not have strong enough flux to remove the oxides off of the leads of the components. I have validated the profile and that i
Electronics Forum | Wed Aug 19 03:33:45 EDT 2009 | rocko
Pay attention that sometimes the ultrasonic energy may damage ICs.
Electronics Forum | Thu Jul 30 03:34:52 EDT 2009 | babe7362000
The parts are from 2000-2004. The temperature at the leads are between 215-220. When the part is removed from the board, some of the leads are nice and shiny and some have dewetting, so I dont think it is a temperature issue.
Electronics Forum | Wed Jul 29 19:59:46 EDT 2009 | davef
What temperatures did you read on the QFP component leads during reflow soldering?
Electronics Forum | Thu Jul 30 13:52:34 EDT 2009 | davef
Thoughts are: * 215-220 temperature at the leads is not real hot for leaded assembly. * It's peculiar for component leads to dewet. Sometimes non-wetting occurs along the edge of the lead where the lead is not plated. * How do the leads of a removed
Electronics Forum | Wed Jul 29 12:48:25 EDT 2009 | mikesewell
Kester R562 is listed as an ORH0, a high activity flux, not sure switching pastes would gain much. What is the finish on the leads? How old are the parts? You could have the parts reconditioned (SixSigma, Corfin, ...others) but this can get costly
Electronics Forum | Thu Aug 06 19:20:09 EDT 2009 | boloxis
easy, just dip the ICs on a very weak solution of Nitric Acid, by very weak I mean like drops of Fuming Nitric acid in a half full DI water beaker. Place the beaker on a Ultrasonic bath and dip/shake the ICs in the solution in 5~ 10 seconds only. You
Electronics Forum | Wed Jan 09 12:53:55 EST 2013 | scais
Hello, We are having issues to solder components. We investigate the issue and found that the pads were having extra gold on the sides. Is it normal? Can we remove this gold 'bleeding from our PCB?' Thanks
Electronics Forum | Thu Jan 10 11:22:48 EST 2013 | pbarton
Looks to me like under etching of the underlying copper and the gold is just plated to all of the exposed copper surface. Is this characteristic the same on all solderable pads? You will not be able to remove this gold.
