Wow Steve, you really have huge nodules in there. You also seem to have some
separation near the edge of the barrel.

But before "I" put my feet in my mouth, a few questions need to be answered:

1- What is the finish of the board? Solder? Tin? Other?

2- What is the base material used in the board? FR4? Teflon (as suggested by
Edward Szpruch)? Other?

3- What is the hole diameter? (This may sound silly but it does have an
effect on plating)

4- Is your hole diameter reduced below minimum requirements when measuring
from nodule to nodule? (This is cause for rejection by the IPC guidelines.)

5- What is the copper plating like? (Need the microsection on that one)

Little note: Solder can have different appearance and still be perfectly
solderable. Shiny, almost silvery is a common situation for some vendors.

Hope this helps a bit. Have a great day,

Alain Savard, B.Sc.
Chemical Process Analyst
CAE Electronics Ltd.
e-mail: [log in to unmask]

-----Original Message-----
Subject: Re: [TN] Nodules in barrel plating...better picture now

Hi Alain!

I've got one more new picture up of some bigger nodules I found. Go to the
same URL: http://www.driveway.com/share?sid=e25a88c4.8e904&name=Pictures

Look at Barrelnodules.jpg...this picture is a worst case picture. But you
are
right about seeing the glass weave pattern in the hole walls in a lot of the
barrels.

The different metal color is not the illumination...it definitely is lighter
in color...almost silver in color. In the picture I've arrowed to where some
of the same plating that is on the board surface has coated a portion of
some
of the nodules near the top of the hole...the rest of the barrel is light
colored and dull looking...

I don't have a cross-section, but I think I will definitely get one done.
Going to call the fab vendor too...I was just trying to understand what this
is before I call. Don't want to put my foot in my mouth.

Still scratching my head though...

-Steve Gregory-

> 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?
>
>  Alain Savard, B.Sc.
>  CAE Electronics Ltd.

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