My
experience is with and Econopak but I think the solder pot and lambda are very
similar. It just has a smaller foot print, shorter rails and preheat.
The
lambda and chip wave settings are not actually rpm. The little things on the
bottom of the motors that look like they might be encoders are generators. The
setting number is a voltage reading from the generators. We ran ours around
1240.
The
top of the wave should be mirror like. Is your machine
equiped with an omega wave? Is it on? other wise it should be
smooth. If the wave is rough it suggests dross build-up in
the solder wave guide.
Wish I
could help more. We did not have the problem with RMA, we did with VOC
free no-clean. It was caused, as mentioned in previous posts by excess
preheat.
Good Luck.
Mike,
I appreciate your help on this, my answers to your
questions are below in parentheses...
Steve: We also run an
Electrovert Electra. We use Alpha's 871-25 OA flux,
similar to your 2331
which we have also used, applied by foam fluxing.
Looking at your photos
it's hard to tell but the "Dross Particles" appear
more like solder
webbing than dross and the "More Dross" does look like
dross. I'm
discounting a problem with the soldermask cure or board design because
you
say it's happening with all your boards. However you may want to verify
soldermask cure as a sanity check.
(you're right Mike, I did think
about it at first, but I know that's not the issue)
1. My first guess
is that you are drying out the flux on the board. The flux
no longer can
act as a lubricant/thermal insulator and the solder and dross
stick to the
board surface. Obviously insufficient flux deposition, excessive preheat, slow
conveyor speed can all contribute. Is it re-occurring in a given band or area
where there may be lack of flux or a hot spot in the preheaters?
(The
flux does kinda' look dry, so I've lowered the preheat, and I still am seeing
the dross. It's random too, not in the same place on the boards. I'm getting
good coverage, I see flux coming up on the topside around the fillets for the
PTH stuff)
If item 1 is not the case consider the following:
2. Are you running the chipwave? This can be a large generator of
dross. We
clean both the chip and Lambda wave pots of dross every two
hours.
(Yes I am, got SMT on the bottomside...and we see the problem
even when we start off with a clean pot)
3. Is the overflow on the
Lambda wave set correctly? If not you will not get
the proper overflow and
dross will build in the wave.
(We're not seeing that at all, the
lambda is not sitting static by any means)
4. How often do you remove
and clean the chipwave and Lambda nozzles? We
remove and clean every 80
hrs of operation. These have a tendency to build
up dross which comes up
thru the wave.
(We are doing that, because it so simple to take
out....)
5. How often do you teardown the entire solderpot and pull
everything out
for a complete cleaning? We do a complete teardown every
1000 hrs. You would
be amazed at how much dross and residue is built up
inside the pot and it's
internal components.
(We've only had the
machine a month now, so we haven't run it that much yet)
Mike, would you mind sharing what your typical belt speed, preheat
settings, and pump RPM setting are?
One other question, this machine
was set up with CoN2tour wave, but we're not using nitrogen, we're not using
compressed air either. Do you think that may have something to do with things?
The Lambda wave doesn't have a smooth appearance except at very low RPM's...is
that normal?
Thanks Mike!!
-Steve Gregory-
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