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
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
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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