I recently made a couple of coolant units based on eBay mister heads
like this one
<https://www.ebay.com/itm/Mist-Coolant-Lubrication-System-Spray-for-8mm-Air-Pipe-CNC-Lathe-Milling-Machine/172271983174?>.
These ones with the straight end on the nozzle seem to be better quality
than the ones with a nozzle that just tapers down to a blunt point. The
problem with all of these eBay misters is that they generate a fine
mist, which gets everywhere. I made some modifications on mine to work
around the problem. The air jet in the model I linked above is just over
2mm diameter. I extended the oil jet using 2mm stainless tube so it now
sticks out about 1.5" past the end of the brass nozzle. This leaves a
thin annular gap for the air to get out. As the area of the air jet is
now very small you can run quite high pressure (60 - 100 psi) with very
low flow. By the time the air reaches the end of the oil jet it has
slowed down a lot and no longer has the energy to break the oil into a
fine mist. You end up with a column of air carrying a stream of droplets
in the middle. On alu oil consumption is minimal. I use a neat cutting
oil and my previous tank was the filter bowl on an air regulator. That
was enough for several days of machining.
One down side of this setup is that it won't suck the coolant up from
the tank. I used a filter canister as my reservoir. Shop air is supplied
at full pressure to the nozzle through a solenoid valve. There is a tee
in the line which feeds a regulator to drop the pressure to ~10 psi for
the reservoir. Theoretically those filter canisters can take 100psi but
that sort of pressure in a plastic tank scares me.
By the way Gene, if you are buying a solenoid valve from eBay, get an
Airtac valve. They are available in a wide range of voltages and
configurations. They are reasonably well made and can handle 100% duty
cycle.
Les
On 13/02/2019 01:31, Phillip Carter wrote:
I use a water filter canister similar to this:
https://www.cnczone.com/forums/uncategorised-metalworking-machines/102934-built-fog-less-coolant-mister.html
<https://www.cnczone.com/forums/uncategorised-metalworking-machines/102934-built-fog-less-coolant-mister.html>
Cheers, Phill
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