William Maugans asked:

>I am experienceing a fine dusting of nodgles that show up anywhere on the
>circuits especially on ground plane areas. The nodgle is dome shaped, higher
>than the surrounding area and very spherical in shape. Bright acid copper,
>everything in spec.I have eliminated deburr, resist (as I see it on panel
>plate also only with much less frequency of occurance).Not a pit from air
>inpengment a dome. Suspect a fungus in the brightener ???

I'm not a circuit board fab person, but I know this:

Those nasty things are spelled "nodule".

You will see them in the PTH's sporadically, they are sites for entrapment
of plating liquid; when you do see nodular plating, the boards will have
lots of blow holes after the wavesolder process in assembly.

I would reject them if you shipped them to me.

The following is speculation:

You have some dust, glass fibers, or other drill imperfections which become
a copper spike after electroless Cu. The protrusion from the hole wall is a
high current site during first copper. This transforms into a spherical
hunk of copper.

If you do not have a very smooth, clean hole wall after drilling, you are
risking nodular plating. I would also guess you that your plating current
may be too high. Filter your bath for suspended solids.



cheers,


Jerry Cupples
Interphase Corporation
Dallas, TX USA

p.s. I am often wrong, but a better than average speller.


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