Hi Evan,
I'm not directly familiar with the Nordson sprayer, but I may be able to
shed some
light on some of the other issues. We use an Electrovert SUPA-Spray
unit [(which
is actually built by Ultrasonic Systems, Inc.) This is not an
advertisment for the
equipment, just an identification for illustrative purposes]. It
consists of a tank for
the flux which is pressurized with nitrogen and this is also the
delivery propellant.
Compressed air is used to drive the reciprocating head that has the
nozzle. I also
use a fan pattern spray. I am also using a no-clean flux.
Some things to look at are:
- What is the conveyor speed. If the board is travelling too fast in
the system, you may get
shadowing and areas that are missed.
- If your system has a traversing head like mine, what is the speed of
the travel. Same shadowing
as above. This may need to be adjusted in concert with the conveyor
speed.
- Try adjusting the spray pressure.
- Try a different nozzle.
A higher speed on either the conveyor or traversing head will mean that
there is less time to apply
a specific quantity of flux.
Although we use primarily single sided boards, I just received a
prototype of a double sided board
and I am now investigating the same thing.
Hope this helps,
Jared Lang
Manufacturing Engineer
Minarik Corp.
901 E. Thompson Av.
Glendale, CA., 91201
818-637-7450
> ----------
> From: Evan D Jones[SMTP:[log in to unmask]]
> Reply To: TechNet E-Mail Forum.;[log in to unmask]
> Sent: Tuesday, June 30, 1998 9:49 PM
> To: [log in to unmask]
> Subject: [TN] spray fluxing
>
> We installed a spray fluxing system on our wave solder machine, based
> on a
> Nordson pulse sprayer, a couple of months or so back but have been
> having
> some problems getting good results. The system utilises a single spray
> nozzle with a fan pattern. The problems we have seen are poor barrel
> fill
> (presumably due to flux not penetrating PTH barrels), and shadowing
> effects
> on bottomside surface mount components.
> We are using a no clean flux. I tried using an active flux, with the
> same
> results, which suggests it is the sprayer setup which is the problem.
> If
> anyone has some experiences that they can share with me regarding
> successful implementation of airless spray fluxing systems I would be
> most
> appreciative. What factors influence penetration? spray pressure?
> extraction?
> Up until now we have been using a foaming fluxer with reasonably good
> results (except for difficulty controlling no-clean residue levels).
>
>
> Regards Evan
>
> Evan Jones
> Manufacturing Engineer
> Bluegum Technology Pty Ltd
> PO Box 609, Wangaratta, Australia, 3676
> Ph: 61 3 5720 2539 Fax: 61 3 5720 2412
> Internet: [log in to unmask]
>
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