Peter
I do not advise "dishwasher" type models for high-tech cleaning, as
their efficiency is not good, they are heavy consumers of water and
electricity per m2 of cleaned assemblies and they are bad at drying
because you have to dry the residual water in the machine as well as on
the assemblies. I know -- I made such machines from 1975 to 1978 and
stopped their manufacture exactly because of these reasons. They were
later replaced by much more efficient batch models, in every respect,
but there was a gap of several years when my company, of that time, did
not offer cleaners, while we sussed these problems out. Of course, the
later machines were more expensive in capital expenditure, but the lower
operating costs compensated in a reasonable amortisation period.
For small equipment, closed circuit operation is rarely worth-while. The
problem is that the wide range of contaminants require many treatments.
A typical sequence may be fine mechanical filtration, single stage
reverse osmosis, two stages of active carbon to remove residual
organics, resp. large and small molecule sizes, either double bed +
mixed bed or two large mixed bed DI column and UV treatment to kill
accumulated micro-organisms that proliferate in the DI columns. In the
smallest system, the cost of this (capital and operating) is more than
that of the machine!
It may interest you to know that I recently visited two factories in
China with three "dishwasher" type machines, between them for defluxing.
These were operating in closed circuit with just carbon and mixed-bed DI
columns. They were not satisfied with the results, the operating costs
were horrendous, they had to buy a separate drying oven and they paid an
arm and a leg for the equipment (I think, if I remember correctly, it
was about $80,000 each). They also had problems at a technical level in
that, in all three cases, the manufacturer had not fool-proofed the
system and the machines became unserviceable within the first few hours.
It took several months before the manufacturer (European) had sorted the
problem out.
If you want more info, please contact me off-line and I'll give you the
name of a Chinese company who may be able to help you, and some others.
Brian
[log in to unmask] wrote:
>
> I am looking for a basic board cleaner and ask for your recommendations -
> makes and models. I have in mind the old dish washer style of thing with a
> resin bed attached for treating incoming water, but you may have more up to
> date ideas than I.
>
> We use a CM for assembling boards, so all the flux removal and heavier duty
> cleaning is done by them. What I need is a cheap water wash machine that
> can dump to drain after filtering out any harmful chemicals and residues
> from rework/repair soldering, handling contamination and stripping of
> humiseal coating. If you consider closed-loop systems to be better, I'm
> open to suggestions, but low cost is the driving factor I have to live
> with.
>
> I have searched the net, but so far have only found fairly high-tech (ergo
> expesive) machinery that goes beyond my needs.
>
> Any and all help, as ever, is much appreciated.
>
> Peter
>
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