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 | 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 | Fri Feb 18 11:25:14 EST 2005 | davef
It's weird that it would be just 0805. When we see this it relates to a single part number and it goes way after a time. We use a Humiseal 1B73. I've emailed you the contact for a person that is very knowledgeable on conformal coatings.
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 | Thu Nov 23 06:05:24 EST 2006 | 1B73
The solid content of 1B73 is too low, especiall when you add large amount of thinner, not easy to get enough coating thickness.
Electronics Forum | Thu Feb 17 15:01:23 EST 2005 | davef
We're not familiar with your DYMAX #984-LVUF. The problem is not with your conformal coating. The problem is with your 0805 [and not all of 0805, probably just those from a specific supplier]. This lack of coverage of components is called dewetting
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