Electronics Forum | Tue May 12 06:44:16 EDT 2009 | jhk71
We do a conformal coating for a customer with copper-nickel-gold pads on his board. The pads are masked prior to coating with a standard gel, containing ammonia. After thousands of boards, being processed like this, now the gold pads seem to be less
Electronics Forum | Tue May 12 22:54:46 EDT 2009 | davef
Did the board fabricator forget to apply the nickel undercoat?
Electronics Forum | Mon May 18 08:34:08 EDT 2009 | davef
It's happened perviously. If that happens, there is a widespread solderabily issue, not just on selected pads.
Electronics Forum | Fri May 15 19:08:25 EDT 2009 | jlawson
Ammonia based masks can create solderability issues after they are removed. You can get non-ammonia based latex mask material but down side is slower cure and cost a little more as they have higher levels of latex etc
Electronics Forum | Mon May 18 02:22:34 EDT 2009 | jhk71
Unfortunately I have no information about the metal layers and the processes. I only see the effect. Is it possible or common that the nickel undercoat could have been forgotten?
Electronics Forum | Mon Mar 21 09:23:34 EST 2005 | sforman1
Some UV cure coatings do not have the correct rheology for sticking to small sharp corners. 984 is one of them. MicroCoat Technologies, Allen, TX makes one that works every time.
Electronics Forum | Wed Feb 23 10:01:00 EST 2005 | frankracine
Dave, Few questions concerning your Umiseal 1B73. To cure your Acrylic coating do you respect specification ( 2Hrs-170degree F) or you go faster than that? What do you use to cure it? Do you have to clean your nozzles each day or each monday beca
Electronics Forum | Thu Feb 17 10:33:53 EST 2005 | Frank R.
I use conformal coating DYMAX #984-LVUF and I don't know if it's a problem of viscosity but 0805 components are not covered properly. We use a dispensor to applied it and we cured it by UV. Even if I apply a thicker layer, the coating seems to have
Electronics Forum | Sun Apr 10 03:25:35 EDT 2005 | Peter
Normally, some conformal coatings do not have very good wetting properties, that should be basic function of a good coating material (the same reqirement as avoid bubbles during coating process)! For UV curing conformal coatings, you can try Lackwe
Electronics Forum | Fri Feb 18 10:10:49 EST 2005 | Frank R.
Thanks Dave, The problem is on all 0805. Do you think it could be a reaction with the flux from the wave or the one in the paste. Do you think the problem is the viscosity of the coating. SPEC = Viscosity 150cP nominal ASTM D-1384. I ask you all
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