Anyone with any sense keeps consumable materials (epoxies, pastes, fluxes
etc) contained as approved materials within process specs. With the  process
spec referenced on the assy drawing, any material change means only one
document requires alteration not every single BOM.

Regards
Ian Fox

-----Original Message-----
From: Bill Christoffel [mailto:[log in to unmask]]
Sent: 15 May 2003 19:52
To: [log in to unmask]
Subject: Re: [TN] Adhesive where no component is loaded...


Carrie,

Just some "Dereky" Comments that maybe make a point !

So if epoxy is not part of the BOM, how do you ship product with an
unspecified, unknown material on the final assembly?  I always thought a BOM
was all materials that are part of the product !  What if you, as a supplier
change epoxy, now this new epoxy causes some latent defect, how do you
implement damage control if the BOM doesn't even show the material being
there ?

Another scenario,  the epoxy dispense goes on the fritz, deposits epoxy all
over the board, board still works.  We just pretend the epoxy is not there
because its not on the BOM and ship the board without any non-conformance
notification ?

Something about a "foreign material" requirement comes to mind !  (Material
either improperly located or not part of the assembly by design is a
reject).

Bottom line , notify the customer and if need be place a note on the drawing
stating that epoxy dots may be present on unpopulated sites.

I'm with the inspector on this one !

Bill C.
Microelectronics Process Engineer


-----Original Message-----
From: Morse, Carrie [mailto:[log in to unmask]]
Sent: Wednesday, May 14, 2003 12:24 PM
To: [log in to unmask]
Subject: Re: [TN] Adhesive where no component is loaded...


Steve, Steve, Steve.
You know....there's always ONE in the crowd.  We had a saying in school ---
"There's a Derek in every Class".
This saying is not meant to offend anyone with the name Derek, but, first
semester freshman class we had
this guy named Derek who just would not let it go.  This poor guy is
probably dead from high blood pressure by now!

Anyway....In addition to letting your inspector know that epoxy is not part
of the BOM, let her know that
solder paste is not always part of the BOM.  Let her know that many times
solder paste is put down at
"No-Insert" locations.  Ask her why THAT is OK and not the epoxy?

Another piece of info that would be interesting is that quite often, board
assembly houses put EXTRA dots on the
board (typically on the rails, but, if no rails, then on the board) to show
that the nozzle did not clog during
glue deposition.  Usually there will be an extra two or more dots somewhere
on the board.

And what about Silk Screen bleeding?  Have you ever seen a perfectly Silk
Screened Letter?  Should we start
rejecting boards at incoming because there is just a bit too much ink on the
letter "U"?

But, with all that put aside, my approach would be that excess epoxy is NOT
identified in the IPC spec as a defect
under these conditions. I would of course let her know that her attention to
quality is quite exceptional, but, that in this case, section 12.1 does not
identify excess epoxy under these conditions as a defect.

Good luck and keep smiling (kill 'em with kindness!)
-Carrie

-----Original Message-----
From: Steve Gregory [mailto:[log in to unmask]]
Sent: Wednesday, May 14, 2003 12:28 PM
To: [log in to unmask]
Subject: [TN] Adhesive where no component is loaded...


Hi All!

The fun never ends...

I've been involved in a rather heated (albeit silly, I think...) debate with
an inspector here, about adhesive being deposited where there is no
component loaded.

As you may surmise from my posts over the past few days, I stencil epoxy,
not dispense. For some reason, the issue has come up with one of my
inspectors here, requesting that I get something in writing from our
customer saying that it's okay to have epoxy deposits at locations where
there is no component loaded. I told her that I wasn't going to do it
because I didn't want to look silly asking our customer if it was okay to
have a glue dot at a location that's not loaded.

Her reasoning is that we're putting something on the board that's not being
called out on the bill of material. My response is that the epoxy isn't
called out anyway, but we have to use it to be able to process this board
that has PTH and SMT on the bottom. "But there's no component there, so
there shouldn't be any glue there." was her response. "But it doesn't make
any difference, it's a non-issue" I calmly replied.

We've been debating this for 2-days now, and I'm about at my wits end.
There's nothing in the -610 or the J-STD-001 that says it's defect, or that
it's forbidden to deposit epoxy where a component isn't loaded, and there's
nothing in the documentation from our customer to keep the unused areas free
from epoxy. I've already spent much more time on this issue than I ever
thought I would. Why this issue has popped-up now, I don't have a clue. Me
thinks it's much ado about nothing.

What is your take on this issue?

-Steve Gregory- ---------------------------------------------------
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