--- "Stephen R. Gregory" <[log in to unmask]> wrote:
> In a message dated 7/27/00 6:58:54 PM EST,
> [log in to unmask] writes:
>
> << First of all the pictures you show look pretty
> bad and
>  I don't believe I would ever ship something like
>  these. However, I want to point out that these may
> not
>  be 'rejectable'. >>
>
> Hi Pete!
>
> It sounds like you've seen this problem before, but
> I do have to question
> your statement of it not being rejectable...
>
> What concerns me with this condition is that there
> are all these little
> bubble pockets that may, or may not, create little
> pockets for flux residues
> or any other sort of contamination to collect that
> can't be cleaned. This is
> aside the issue that you say everything is probably
> covered well with
> soldermask.

Steve,
From the pictures I can't see if there are pockets
that will collect flux residues so this might be a
fear. But a question back to you - Given the flux you
are using is there a fear that entrapped flux would
cause a problem in the future?  It seems to me that
with the use of low and no clean fluxes that the fear
of entrapped residue is much less important today than
it was when active fluxes were used.

>
> Let me ask you, if you were an assembler (these
> boards go into geophysical
> equipment...otherwise known as oil-well electronics,
> not downhole stuff
> though) would you accept these boards and build them
> for your customer?

If I could sell the product to my customer then the
answer is yes I would accept these boards.  The
problem is your customer.  I would not assemble the
boards until my customer saw the anomaly and agreed
that it is not a functional defect.

> the picture called "barreldefect.jpg" at my
> freedrive is also another defect
> that we've seen with these boards. That picture is
> of a PTH resistor network
> hole (albeit the worst one we've found), but there
> also has been some "less
> than desireable" barrels that I've seen.
>
> Problem is, we're stuck between a rock and a hard
> place. We've been
> inspecting every board as thoroughly as we can to
> try and get the pick of the
> litter, because we must meet a committed delivery
> schedule. During wave we've
> had pin-holes and blow holes that I think are
> because of the hole
> quality...we've spent many hours of extra touch-up
> because of this.


Your story is pretty common in the industry.(which is
a sad commentary)  The problem is that you are
visually inspecting for a problem that can't be
visually inspected.  The fact that you found a barrel
with a slug of something in it is interesting and
might be meaningful but it's probably not related to
your problem.  If the boards don't have any
contamination in them (which your visual inspection
should have seen) then you've probably got light
plating.  If your shop is in the area I would run down
with a couple boards and have them cross sectioned.
At the very minimum there should be .0008 to .001" of
copper in the hole. You'd like to see more but if you
didn't specify anything then this is what you should
receive without asking.
>
> When I see various issues (it's not just mask
> issues, or hole quality
> problems, there's also boards that have SMT pads on
> fine pitch locations that
> didn't wet with solder during HASL that were shipped
> to us), I just wanna
> pull my hair out!! We get crap and are expected to
> turn it into gold...such
> is the life at CEM's.
>

I realize its tough being in the middle, especially
when many times your customer is specifying a board
shop that you know puts out bad quality.

Good luck - most of the board houses I am familiar
with are more than willing to work out what amount to
straight forward problems.  Light plating, puddling
mask, debris in holes are all fixable problems.  Oh
yea one more thing to pass on to your purchasing
people.. The true cost of the board is rarely
reflected in the price of the board.

pete


> Didn't mean to dump on you, but this is what I deal
> with every single day. If
> it's not a board problem, it's a component issue, if
> it's not that, it's a
> B.O.M. problem, if it's not that, a machine is
> down...yada,yada,yada
>


> Anybody got any Prozac?
>
> -Steve Gregory-
>
>
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