Bill

As you do not mention your end product type and therefore the required quality, it is
almost impossible to give you a valid answer. Perhaps you would e-mail me off net with
some further details? In the meanwhile, I will send you privately a forwarded copy of
this message with web site details of some semi-tech, semi-commercial info (castigation
avoided!).

My general recommendations for machinery are:
wash: solid jets with high volume water at medium-to-low pressure (say, 2-5 bars)
angled to assist in under water-penetration. The pump power, as a rule of thumb, should
be ca. 1 kW/metre of wash bars. Machine design should be such that, preferably, washing
occurs over a minimum of 2 minutes with a ratio of any given point receiving water from
the jets for at least 50-75% of this time. Temperature should be ca. 50 deg C. At 60
deg C or more, some OA flux residues will become less soluble (comparable to runny egg
yolk residues on a plate requiring cold washing before hot).
rinse: this is more critical than the wash. It requires a particle (droplet) diameter
smaller than the smallest gap under components in order to replace the wash water held
there by surface tension (capillary action) and these droplets must have sufficient
velocity to creep into the space and displace an equal volume of dirty water from
t'other side. You must then have the process last so many times that the total volume
of retained water is displaced once and this will reduce the residual contamination to
about 20-30% of the original. This is then repeated n times until the residual
contamination is acceptable. In my experience, for superb cleaning quality, n must be
typically 8-10, but, depending on the machine, this can happen in a very short time,
maybe less than 30 seconds. So we are talking about a metered volume of DI water, low
pressure, small droplet size but directed to under the components.
drying: this is the most critical stage. Good mechanical drying (centrifuging or
***adequate*** air knifing) will remove 90% of the residual water, including an
equivalent quantity of residual contamination and, at the same time, will save you
80-90% of the energy costs, compared with evaporative hot-air drying for the same
volume of water. Of course, the latter is still required for the remaining 10%.

There are very few machines which will do all this well.

Hope this helps.

Brian

"Kasprzak, Bill (esd) USX" wrote:

> 'netters:
>
> I've recently completed a study to replace our old, vintage mid 80's,
> wavesolder machine and in-line cleaner with new equipment. I've made a
> selection but I'd like to get a cross section snap shot from you folks that
> answers the question...
>
> If given a low to medium volume, high mix, mixed technology, printed circuit
> board assemly line that will use water soluble flux... (Assume for the
> moment that money is no object.)
>
> What wavesolder and in-line cleaning system would you recommend?
>
> Not looking for dissertations here but rather a selection and a sentence or
> two.
>
> My intent here is to make sure I haven't overlooked something.
>
> Disclaimer: Answers given will not be construed as advertisement subject to
> severe castigation from anyone on this forum.
>
> Thanks to all who can respond.
>
> Bill Kasprzak
> Moog Inc.
>
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