[johnnyt74]

Hi all,
I'm just in the process of building my cnc machine. I have bought a 3KW water cooled spindle and been hunting for a solution to cool it. I've seen lots of home-made solutions using PC fans/radiators etc.


I've found a pump on eBay -
80W Water Pump Spindle Motor Water-cooled Circle Pump for CNC Engraving Machine | eBay

I'm worried though because that advert mentions changing the filters etc regularly. I would prefer something with less maintenance.



I was thinking of rigging this up just to a bucket of water but wondered if anyone knows of any pre-built closed loops solutions out there. My cnc machine is going in my attic and I'm concerned about possible leaks and transporting new liquid up there and mess when it comes to cleaning etc.


Can someone point me to a closed loop system with very little maintenance needed. Either a commercially available one or a design for one that I can build myself (ideally something tried and tested).



Thanks for any advice/help on this :-)

[plcamp]

Do not use this pump....look for one that is refrigerated for proper temperature control during prolonged runs

[johnnyt74]

Do not use this pump....look for one that is refrigerated for proper temperature control during prolonged runs

Thanks for the advice plcamp. I've not seen refrigerated pumps? Do you have a link to a recommended one?

I was going to attach a radiator/fan combo to this pump in order to cool the water/glycol?

[ger21]

I've never seen anyone use a refrigerated cooling system. Most people just use a pump in a bucket.

[johnnyt74]

I've never seen anyone use a refrigerated cooling system. Most people just use a pump in a bucket.

Hi Gerry

Thanks for the help (again). So, does everyone just make home-made ones? Is there no simple commercial closed loop systems out there to just buy off the shelf that you know of?

If not, I'll just get a pump/radiator/fan/bucket etc and make something.

Thanks :-)

[R0bbie]

Hi,

I have a 1.5 Kw water cooled spindle and had already bought a small radiator with fans normally used for computer CPU water cooling.
I didn't have a pump jet so I went to gardening store and bought a small fountain pump.
I have put this pump in a 2 gallon plastic container filled with car coulant, no radiator, just circulating the fluid and there is no problem keeping the spindle cooled.
Unless you are routing for hours and hours continuously I do not think there will be a problem.
Just monitor the temperature of your spindle, if it goes to high just add more fluid volume or a radiator.

Just my experiance.

Regards,

Rob.

[johnnyt74]

Hi,

I have a 1.5 Kw water cooled spindle and had already bought a small radiator with fans normally used for computer CPU water cooling.
I didn't have a pump jet so I went to gardening store and bought a small fountain pump.
I have put this pump in a 2 gallon plastic container filled with car coulant, no radiator, just circulating the fluid and there is no problem keeping the spindle cooled.
Unless you are routing for hours and hours continuously I do not think there will be a problem.
Just monitor the temperature of your spindle, if it goes to high just add more fluid volume or a radiator.

Just my experiance.

Regards,

Rob.

Thanks for the advice Rob. I've just been looking at a few YouTube videos that seem to be similar setups and this looks like the way to go.

Cheers :-)

[JerryBurks]

I have a 2.2kW "water cooled" cylindrical Chinese spindle but do not use any liquid coolant. The spindle is installed within the dust collector shroud and the air flow of my 1hp dust collector is more than sufficient to keep it cool, even on very hot California summer days and full load. The stick-on thermometer never goes above 130-140 F. This has been working perfectly for some 5 years now.

For me, all that pump, reservoir, radiator, hose and anti-fouling crap is just redundant.

[johnnyt74]

I have a 2.2kW "water cooled" cylindrical Chinese spindle but do not use any liquid coolant. The spindle is installed within the dust collector shroud and the air flow of my 1hp dust collector is more than sufficient to keep it cool, even on very hot California summer days and full load. The stick-on thermometer never goes above 130-140 F. This has been working perfectly for some 5 years now.

For me, all that pump, reservoir, radiator, hose and anti-fouling crap is just redundant.

Wow! That's good to know.

Yesterday I ordered a small pump and radiator so I'll rig something up just in case but good to know that they don't need much cooling anyway.

I'm only going to be cutting wood so won't really be pushing the spindle.

Thanks again :-)

[plcamp]

I've never seen anyone use a refrigerated cooling system. Most people just use a pump in a bucket.

” Typical run in for spindles is a starting point of about 400 rpm,
up to max in 500 rpm increments, in steps of 30 - 45 minutes.
Check housings for excessive heat as you go.
Then reverse and do it over!
Watch temperature. If it gets hot, stop let cool and do over.

The ideal equilibrium operating temperature is 95 to 115 degrees F. Maximum temperatures should not exceed
170 degrees F.

If this can be maintained using a simple pump and water reservoir, great. Otherwise more elaborate methods may be required i.e. radiators or chilled coolers

[CNCMAN172]

johnnyt74,

I have a 3KW water cooled spindle that I have run for many years now. I use a pond pump and it works just fine. You just need flow through the spindle. JerryBurks, I have no idea how you managed to get your spindle to stay alive without using coolant, that is a miracle. Most people who have forgot to turn on their water had a disposable toaster in about 20 minutes. While there is a good deal of mass in the spindle housing they do heat up depending on the load on the spindle.

Johnny do yourself a huge favor and get a water pump. I also put on a little indicator that spins when water is moving so I can check on it during long runs. Some people put on temp indicators and actually tie it all back into their estop circuits to ensure if the temp starts to get hot it turns of the spindle and halts the machine. I have never gone to that extreme but if you leave the machine unattended for long periods of time that is not a bad approach give you some piece of mind.

Plcamp,
While "typical spindles start at 400 rpm" those are not Chinese water cooled spindles. They are designed to work between 6000 and 24000 RPM. They tend to get hot quick if you run them really slow and have almost no torque at low RPMs. The manufacturer warns the buyers to ensure they set their VFD parameters properly to avoid destroying their spindles.

Russ

[JerryBurks]

.....JerryBurks, I have no idea how you managed to get your spindle to stay alive without using coolant, that is a miracle. Most people who have forgot to turn on their water had a disposable toaster in about 20 minutes. While there is a good deal of mass in the spindle housing they do heat up depending on the load on the spindle.....

No miracle at all. The air flow of the dust extractor is routed along the spindle in an approx. 1" wider annular duct (makes routing of the dust hose easier as well). That said, my spindle is not held in place with bulky clamping plates that would obstruct air flow but with two strong steel straps that hold it in a shallow aluminum cradle. The 1hp blower of the DC creates probably 10 times the flow of the fan of an air cooled spindle which compensates for the lack of cooling fins and provides probably better cooling than the water trickle that can be forced through the spindle channels.

In any case, I will state under oath that my spindle does not get hot at all

[CNCMAN172]

Jerry,
Now I understand, yeah lots of air flow will remove the heat. I just figured you had a magic spindle.
The water cooled spindles have to way for the air to flow inside the spindle, so your airflow is on the outside and I guess the mass of the spindle staying cool addressed the heat build up. First I have heard of someone taking this approach.

Russ

[mactec54]

I have a 2.2kW "water cooled" cylindrical Chinese spindle but do not use any liquid coolant. The spindle is installed within the dust collector shroud and the air flow of my 1hp dust collector is more than sufficient to keep it cool, even on very hot California summer days and full load. The stick-on thermometer never goes above 130-140 F. This has been working perfectly for some 5 years now.

For me, all that pump, reservoir, radiator, hose and anti-fouling crap is just redundant.

You got lucky

130-140F is above what the temperature should be, 120F is normally around the max for reliability, the higher the temperature the grease will run from the bearing surfaces, Plus you have the motor coils that if to hot the insulation will break down

If you are measuring that temperature on the outside, on the inside the Bearings will be 10-20 degrees hotter

[johnnyt74]

johnnyt74,

I have a 3KW water cooled spindle that I have run for many years now. I use a pond pump and it works just fine. You just need flow through the spindle. JerryBurks, I have no idea how you managed to get your spindle to stay alive without using coolant, that is a miracle. Most people who have forgot to turn on their water had a disposable toaster in about 20 minutes. While there is a good deal of mass in the spindle housing they do heat up depending on the load on the spindle.

Johnny do yourself a huge favor and get a water pump. I also put on a little indicator that spins when water is moving so I can check on it during long runs. Some people put on temp indicators and actually tie it all back into their estop circuits to ensure if the temp starts to get hot it turns of the spindle and halts the machine. I have never gone to that extreme but if you leave the machine unattended for long periods of time that is not a bad approach give you some piece of mind.

Plcamp,
While "typical spindles start at 400 rpm" those are not Chinese water cooled spindles. They are designed to work between 6000 and 24000 RPM. They tend to get hot quick if you run them really slow and have almost no torque at low RPMs. The manufacturer warns the buyers to ensure they set their VFD parameters properly to avoid destroying their spindles.

Russ

Russ,

Really good info there. Thanks.

This is what I bought last night...
Aluminum 240mm Water Cooling cooled Row Heat Exchanger Radiator+Fan for CPU PC D | eBay
SC-300T 12V DC Wasserpumpe und Pumpentank für PC CPU Flüssigkühlung System Wsser | eBay

Along with some pipe. I think that should be fine.

I am going to tie in the Inverter Running signal to the pump so it starts at the same time automatically.

I like the idea of monitoring the temp though so I might do that too now you've given me the idea.

:-)

[CNCMAN172]

johnnyt74,
That setup should work fine. In my case I just run the water into a five gallon bucket that is sealed at the top and I keep the bucket about 2/3 full with a mix of antifreeze and distilled water. The mass in the bucket is large enough to keep the water cool all the time. After 12 hours of running cutting aluminum on my machine the water is only slightly warm.

Russ

[johnnyt74]

johnnyt74,
That setup should work fine. In my case I just run the water into a five gallon bucket that is sealed at the top and I keep the bucket about 2/3 full with a mix of antifreeze and distilled water. The mass in the bucket is large enough to keep the water cool all the time. After 12 hours of running cutting aluminum on my machine the water is only slightly warm.

Russ

What ratio of anti-freeze to distilled water do you use out of curiosity? Is it roughly the same mixture that you use in cars or less/more etc?

Thanks again :-)

[CNCMAN172]

I usually put one gallon of antifreeze in three gallons of water. This is really just to keep corrosion away and help prevent rust on the inside of the spindle water cavity. I have had no issues. DO NOT use tap water as there are many minerals in tap water and you can have them build up and plug the water ways cut to all the calcium.

Russ

[alan_3301]

I've had a dinky fountain pump slowly pumping a trickle through the spindle into a bucket for a few years now. That trickle stopped about 6 months ago, because of a small bacteria plug in the spindle outlet.
I just finally got around to blowing it out. These 2.2kw spindles are rated at 7 amps I believe, but I have never seen it go over 2 amps, and 99% of the time is sitting right around 1 amp. With no coolant flow at all, my spindle never warmed up enough that I could tell a difference between it and ambient. My jobs usually only have around 15 minutes of run time though.

Overkill is definitely not needed for most applications.

[CNCMAN172]

alan,
Cut some aluminum for 4-5 hours and you will notice they get much warmer when they have a heavier load. The amperage also climbs under load, depending on what you cut.

Russ