Hey Steve,

Small nodules inside plated hole walls are not unusual, however in the case
of your boards it seems to be the termination of the glass-weave that is
found in the prepreg and laminate. This may suggest thin plating thickness.
What is the finish on these boards? This kind of finish is not usually
expected after HASL, but may be more visible with other finishes.
For the dirrerence in colour, is it possible that the difference comes from
the variation of the illumination angle?
Did you do a cross-section, microsection, of the board?

Just trying to help,

Alain Savard, B.Sc.
CAE Electronics Ltd.

-----Original Message-----
From: Stephen R. Gregory [mailto:[log in to unmask]]
Sent: September 11, 2000 12:52 PM
To: [log in to unmask]
Subject: [TN] Nodules in barrel plating...

Hi ya'll!!

Got another picture for ya to look at for me. We've got some PCB's in
receiving inspection that has these little nodules in plating inside all of
the barrels. Go to:

http://www.driveway.com/share?sid=e25a88c4.8e904&name=Pictures

and look at Barrelplate.jpg to see what I mean. These are microwave PCB's
and
have almost all of the surface area on both sides covered with with solid
metal planes, and no solder mask.

Is this a normal appearance? The plating inside the barrels look to be a
much
lighter color than the plating on the surface planes on the PCB...you can
see
that in the picture as well. I don't know what I'm looking at, maybe someone
could help me. I'm being asked if this is okay...I don't know if it is or
not. I'll try and take a better picture if I can...

Thanks!!

-Steve Gregory-

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