[eBirdman]

Hello, I am converting PM-727v to CNC. Currently I am ordering parts to make a fogless mist cooling system . I am searching for the specs of the fogless mixer. If you have the Fogbuster mixer or you've made a similar mist mixer working as good, please share the following information:
the diameters of the air pathway and coolant pathway inside the mixer and also the OD and ID of the respective tubing lines.
Thanks in advance for any useful information.
Vlad

[Jim Dawson]

I did mine a bit different, in that I use a pressure tank fo feed the coolant. Can control the air and fluid independently. Constant fluid flow at any air flow. Puts out micro droplets, no fog.

Flow controls on both air and fluid lines, 1/4 inch air, and coolant feed lines.
1/8 tubing is normal nylon water line, available from any hardware store.
The 1/8 line goes right through the Tee and down the center of nozzle tube


I sized the 1/8 tube to stick out the end of the nozzle 1/8 inch or so


Harbor Freight 20 lb sandblaster pressure tank, about 4 gal. coolant capacity.
Normally pressurized to about 30 PSI.


and on my dirty mill.


At about 5% flow, about 1/2 cup / hr


At about 40% flow, almost never run it this high, 5% is more normal

[eBirdman]

Jim, thank you for sharing your experience ...
Does 1/8" Tee have the same 1/8" diameter pathways for both air and fluid? meaning that air hose gets narrowed to 1/8" as it enters the mixer? Also I don't see on those pictures how the black discharge hose from the sandblaster tank turns into the clear fluid delivery hose ?
I understand you regulate the cooling fluid pressure at the sandblaster tank and probably the air pressure at the dedicated air compressor , right? Then indeed any regulating valves at the mixer are redundant ... unless air compressor has more users with different pressure needs at the same time...
Thanks again
Vlad

[SCzEngrgGroup]

For a real FogBuster equivalent, you need a very long, small "nozzle". I used 1/16" ID copper tube bought from the hobby/model store. The whole idea is to have very high velocity at the nozzle outlet, and a large expansion, which vaporizes the coolant, dropping its temperature dramatically. The flow out of the nozzle will be VERY cold, and the "jet" should be completely invisible. When pointed at a metal target, you should see little or no liquid coolant, other than occasional tiny droplets leaving the area very quickly.

The original FogBuster patent is available on-line, and details all the critical dimensions of the real product.

Air pressure does NOT need to be very high - 15PSI or so is typical for FogBusters. A pressurized coolant tank will go a long way towards mitigating clogs, and maintaining a consistent flow of coolant. You need a PRECISION needle valve to control the VERY SMALL coolant flow. The coolant should be injected into the nozzle through a very small (0.040") radial hole, near the inlet end of the nozzle.

Use a coolant MADE for misting, NOT a normal flood coolant. KoolMist works very well, and a single gallon will last for years of hobby use.

Somewhere in this forum is a thread I created 10-12 years ago that detailed the FogBuster clones I built and used for years.

Regards,
Ray L.

[Jim Dawson]

The design has been changed a bit since those pictures were taken.

The tee is just a standard 1/8 pipe tee. The the black fluid hose (standard auto fuel line that I had on the shelf) has a 1/8 NPT/barb fitting on the end then that is connected to a short length of 1/4 vinyl clear tubing that way I can see the fluid is being supplied to the system. You could run any tubing from the tank to the flow control. Then to the 1/8 NPT to 1/8 tube fitting.

The air supply just comes from from the shop air, through a regulator to the tank, controlled by a solenoid valve that is controlled by the mill controller. Both the tank supply air and the nozzle supply air are controlled by the solenoid valve. The pressurized tank is simply to keep positive pressure on the fluid, the air and fluid flow control is done with the flow control valves on the tee.

[rcheli]

Thanks eBirdman. How convenient, I was just thinking about building one these myself.

John

[eBirdman]

Ray, the original patent has only dimensions of the nozzle tube. Mixer' coolant and air pathways sizes are not given. Your info about the injection hole for the coolant into the flow is indeed important info... this renders my search for a precise pathways sizing less important, or at least coolant path diameter is not that important as it's resulting (needed) pressure gets created only at this small injection point been adjusted. As for the air pathway I have Jim's recommendation - 1/8" diameter.
Currently I don't have air compressor but I settled my research to the California Air Tools 8010 Ultra Quiet & Oil-Free 1.0 hp Steel Tank Air Compressor, 8 gal . It is normally around $200 but I found it for $143.49
from https://www.amazon.com/gp/product/B0..._saved_title_1 I saw somebody's presentation and it's quiet running is impressive...

Good suggestions, thank y'all
Vlad

[maxspongebob]

Hi Vlad. I published my data on GrabCad. You can download them here. https://grabcad.com/library/mist-coolant-nozzle-1

[eBirdman]

Bob, thank you for sharing - meticulously done mist system... This system spills over from CNC machining into the Visual Art
I downloaded the model (not sure yet what file I'll be able to import in my SolidEdge... stp or stl)...
Can you reveal what solenoid are you using? Is it 24v powered from your CNC controller PS?
Also what air pressure regulator are you using and where did you buy them (looks like 4 of them in the picture)?

[maxspongebob]

I have 4 regulators on the board but I only use 2 for the mist system. If you look at the panel at the upper right is the input from the air compressor @ 150 PSI. The regulator on the upper right just regulates the pressure down to 50 PSI for distribution on the board via the manifold in the Upper Center. On the left is the regulator that goes to the dust off hose at the front of the mill. It gets the pressure down to 25/30 PSI so the chips don't wind up all the way across the room. Below the manifold is the solenoid that is controlled by MACH. The output of the solenoid goes to the inputs of the 2 center regulators and to a 60 PSI pressure relief valve. Of these 2 regulators, the top pressurizes the contents of the reservoir and the lower pressurizes the air line to the mist nozzle.

I usually keep the pressure in the reservoir about 2-3 PSI greater than the air. This gets the proportions of air to fluid just about right and the final adjustment of how much fluid is dispensed is done using the needle valve on the nozzle.

BTW, it is WD-40 in the reservoir.

In my experience, the key is to keep the velocity of the air low enough so the fluid is NOT atomized but the chips are still blown away. When atomization that happens you fill the room with the fluid fog and the wife tells you she smells something, (you also breath it in and can smell nothing else for days). Fog is BAD. Lower pressure = spittle. I can't think of a better term for how the fluid comes out of the nozzle. It makes small little droplets that blow across the work.


Regulators:
It's important to get the lower pressure regulator so you can have very fine adjustment. This is 0-30 PSI. If I did it over I would look for a 0-20 or 0-15. I have never used much pressure. Never more than 5-10 PSI on the air side.
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

Solenoid:
This is a 3 way valve. It runs off 12 volts but I am sure they have a 24 volt version. You need this so that when the solenoid is turned off the pressure from the output side is routed back out or dumped to the muffler. You don't want the system to continue to have pressure when it is turned off.
https://www.amazon.com/gp/product/B00VTX7Q6I/ref=ppx_yo_dt_b_asin_title_o01_s01?ie=UTF8&psc=1

24 volt version:
https://ussolid.com/1-4-dc-24-v-pneu...ition-npt.html


Reservoir:
This is meant for a water filter. I added a pickup tube to the output so it goes to the bottom of the reservoir where the fluid is.
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

Manifold:
Just to distribute air to future things.
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

Needle valve:
I used the guts from this in the brass nozzle.
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

Hose Barb fitting:
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

Pressure dump muffler:
This is to release the back pressure when the system is turned off without a POP.
https://www.amazon.com/gp/product/B01LXQY3BL/ref=ppx_yo_dt_b_asin_title_o06_s00?ie=UTF8&psc=1

Relief Valve:
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1


I need to make a schematic and post it also.

[eBirdman]

Bob, this answers a lot of questions ! including those I am yet to come up with Saved me and many others a lot of research time. I did not know about using solenoid reverse port to release the system pressure, indeed very important.
Some things I don't understand yet... What is relief valve for? If pressure of all the system outside of air compressor tank gets released by reverse solenoid port with muffler, then why manual relief valve?

P.S. I copied all your post to my CNC related notes.

[maxspongebob]

The automatic relief valve is a safety mechanism like an E-Stop switch or a GFI outlet. With 150 PSI as the line pressure, there is a possibility, if things go wrong, that the reservoir could get over pressurized and explode. The relief valve keeps this from being a possibility. The reservoir itself was designed to be a home water filter where the water pressure is usually around 80 PSI, so it is not designed for more.

[109jb]

i just used an air regulator and a lubricator like the one in this link https://www.northerntool.com/shop/to...EaAitrEALw_wcB

Air comes from the compressor to a shutoff valve, then the regulator, then to the lubricator and then into a 3/16" ID hose and finally into a 1/8" id brass tube. The lubricator has a needle valve built into it for adjusting the fluid flow. Works great. I can adjust down to an imperceptible mist where I basically have to put a piece of paper in front to determine that lubricant is coming out. I run about 20 PSI. I had always intended to make one, but I had everything except for the tubing already so just threw it together to try it and it worked well enough that I never made anything else.

For my new machine I'm putting together I did just order this: https://www.amazon.com/ChgImposs-Coo...29-spons&psc=1

[eBirdman]

Bob, it would be a big help for many DIYs if you can find time and make a dedicated post with mist system basic schematic (for simplicity skipping other side uses of the compressed air) showing included components, connections, sizes of the tubing lines and NPT threads and also including pictures and info you already generously shared here... this post would attract many visitors...
I, for one, already got lost choosing pipelines sizes and NPT threads... many choices, don;t know which go where ... but this could be clearly shown on the schematic.
With much appreciation,
Vlad

[eBirdman]

Hi 109jb, this regulator from northern is interesting idea but I don't know how much of oil you can get continuously from 0.68 oz (20 ml) bowl capacity ? How long can you cut steel with this? Also is 20 psi the smallest pressure you can get?

[109jb]

That isn't the exact lubricator I have. Mine is an old one of unknown brand, but it probably holds about 4 oz, and it can run for hours the way I set it. I'm sure you could run it lower than 20 psi, but 20 is what I've run my regulator set at. I should also mention that I use the 1/4 ball valve to throttle it as well because it is easy to do it that way so in reality i probably am less than 20

[RCaffin]

I use a constant air blast with a pulsed misting: MQL. All MYOG.
The air blast is through common LocLine hose with a pneumatic solenoid, under control from M8.
The misting is through a bit of hypodermic tubing at the LocLine nozzle: the lube is sucked out by venturi action. The lube reservoir is maybe 100 mm above the valves. It is controlled by another pneumatic valve and M7.
The lube itself is 3 parts kero to 1 part olive oil - the latter is skin-friendly and the kero cools the job and the cutter down with the air blast. The oil lubricates the cutter. So little is used that there is no fog and no smell (well, a faint kero maybe).

Cheers
Roger

[eBirdman]

Bob , what diameter tubing are you using for the air and for the coolant mix from reservoir ? Do you use the same tubing for both?

[maxspongebob]

The tubing for air and fluid is 1/8" ID Vinyl. All the tubing on the distribution board is 1/4" LDPE.

[eBirdman]

Are all your tubes approx. similar sizes 1/4" OD and 1/8" ID which can also be interchangeable with 6mm OD and 3.5mm-4mm ID in the same fittings ?
I am lost in such seemingly simple task as choosing fittings and proper tubes to fit
For ex. these 1/4 NPT fittings
https://www.amazon.com/gp/product/B0...sc_act_title_2
work for both 1/4" OD tubes and also for 6mm OD, are they?