VFD Spindle Opinions

[olf20]

For those of you who have a inverter spindle
what brand, size, and whether it's water cooled
or not.
Thanks for any information.
olf20 / Bob

[adze_cnc]

Many times a quick search can provide some useful information:

a search for "VFD spindle" produced these gems: here and here

[rscrawford]

I have had a few HSD air cooled spindles. My current one is a 12hp ATC. I would stay away from water cooled, as its a pain keeping the water clean and having a large enough reservoir that it doesn't overheat. Mine has a fan that runs constantly, as well as compressed air blowing through. Can run full power with 100% cycle duty.

[Mikehell]

I find water-cooled is not nearly as much of a hassle as I thought it would be. Spindles don't get so hot that you need a chiller and big tank, as you would with a laser.

Is your machine a production machine or a hobby machine? I have Hunyang Kit on my home machine (water cooled) with good success. Problem with air cooled on a hobby machine is they just don't fit, as most air cooled are square.

[martin54]

I think there are arguments for both air-cooled & water-cooled but a lot of what is said depends on your location as much as anything. I have read that on long runs people have had to pause halfway through a job with an air-cooled spindle because it started to overheat. Others say that they have done long runs without problems, when you look at the 2 posts the difference is where they are in the world & the temperatures associated with those places. I am in the UK where it never gets that hot so an air-cooled spindle would probably be OK but I can't say for sure because I have water-cooled spindles
I opted for water cooled because I was told they were a lot quieter not having the air cooling fan at the top. both my spindles are Chinese spindles because I took the chance to save some money They did both come from sellers who other people had bought from & not had problems.
I also don't think a water-cooled spindle is really a hassle to run & maintain & I guess it depends on what your idea of a large reservoir is when it comes to how much water you need. I have a 25-litre barrel that is half full, about 2 3/4 gallons in total. It is a mix of water & antifreeze, the barrel has a cover over the top to stop the water from getting dirty & as part of my CNC maintenance I change it every 6 months although I could probably do it as an annual maintenance item to be honest.

For me they work well but I have never used a router so can't compare, one reason I went down the route I did was because when I started looking for router bits some of the bits I wanted seemed to come in shank sizes that there wasn't a collet for with any of the routers that I already owned, having a spindle with an ER20 collet chuck means that shank size is never a problem when it comes to buying bits, I have full sets of metric collets & imperial collets for all the imperial size shanks that I have

[Leo]

I have a water cooled 4hp chinese spindle.

First one got plugged up. MY FAULT - I was not at all careful about keeping the water clean.
I fixed it, and it runns, but, My skills and tools for that sort of repair are limited, and it does have issues
It works as expected, but I don't trust it to last - so it is on the shelf as a backup.

SECOND one
I made a coolant tank based on the industrial machines I have worked with.
The tank has baffles that does not allow sediment or floating debris to be able to work through to pickup
I installed a flow meter and temperature gage to monitor during running
I use ONLY distilled water. Additives do not enhance the cooling capacity of water.
I clean it out in January and replace the water.
Been 2-3 years - no issue

[rig gap]

Just to add to the pile, I have been running a 2.2 kw air cooled spindle on my home built CNC router for about 6 years with no problems, and in my business of doing machine repairs I deal with both air and water cooled spindles on a variety of machines.
The biggest differences I see between air and water cooling, is water cooling is quieter due to not having a cooling fan, and the air cooled spindle has a limited "slowest " speed due to the need for air flow generated by the speed of the spindle.
Air cooled spindles are not limited to square housings and are available in round housings just like the water cooled models.
Coolant for water cooled spindles is usually a mixture of water and a non-toxic antifreeze (RV antifreeze is popular), and is circulated under low pressure, so if there happens to be a leak (I've never seen a spindle leak, but have seen coolant lines leak) it's not likely to flood the shop...it can make a mess but usually not serious, and changing the coolant depending on usage is just routine maintenance.
Bearings in high speed spindles are made to run for extended times, routers are not...think about how long you actually run a router when you use it by hand.
As far as choice...either one would be a good choice over a router. I would make the decision on your specific situation. Do you have a place to put a storage container for the coolant, and do you have sufficient source of power for the spindle (either air or water cooled). A 3 hp (2.2 kw) spindle would require a 220 volt service and can run ER-20 collets for 1/2" shank tools...a 2 hp spindle would need 110 volt service but you would be limited to ER-16 collets for tools with 1/4" shanks.

[scotttarnor]

Water cooled here, I have a closed loop using components found in a CPU cooler. So far no issues the spindle doesn’t even get warm.

[martin54]

I use ONLY distilled water. Additives do not enhance the cooling capacity of water.

You are quite right Leo they don't but my workshop in Scotland gets very cold in the winter & I am not up there every single day so there is a very good chance that it would freeze,

[tomgardiner]

Umm, "water cooled spindles are quieter..." not once they are cutting. Don't make your decision based upon the fan noise of an air cooled spindle - mine is below 48 db.
HSD 5kW.

[Burnside]

Not sure on the “quiet” argument once the spindle is doing its job of cutting. I have an HSD 2.2kw and Mitsubishi VFD. Love it. The fan isn’t too loud but does hum. Maybe a pump is quieter but I can’t hear the fan when it’s cutting LOL.

As far as temperatures go, it’s always cool to the touch l, but I don’t do a lot of long 3D carving

[rig gap]

I have to apologize and say I'll have to be more precise in what I say.

Water cooled spindles are quieter than air cooled spindles when they aren't cutting, and both are much quieter than a router when they aren't cutting.

Sorry for the mistake.

[Tailmaker]

Here is a weird one:
I have been using a round Chinese 2.2kW spindle for the last 10 years. It is technically water cooled but the water ports are plugged, and I use exclusively the dust collector air flow for cooling that is routed along the spindle through a plastic shroud. The stick-on thermometer never shows more than 20 deg C above ambient, even at full spindle load. Not really surprising, since several hundred cubic feet of air per minute have way more heat capacity than an aquarium pump water trickle and the spindle has a decent surface area for heat transfer. That said, my spindle is not held with horizontal plate clamps (would obstruct air flow) but is seated in an aluminum cradle with slim steel bands.

I posted my solution a few times on the CNC-Zone forum where it was kind of poo-poo'd but hey, has worked for me a long time...

[wb9tpg]

I put in a 800W water cooled spindle by G-Penny on my Shapeoko. Bought the kit from G-Penny on AliExpress that included the VFD.

Reasons I bought it
- wanted water cooled so it'd be quieter. It is quieter unless I use dull bits.
- only use 1/4" and smaller bits so I didn't need anything bigger than 800W
- it fit in the standard router mount using the Carbide3D supplied spacer.
- this spindle has 2 bearing on top and bottom.

Things I learned along the way (some expected)
- Had to make my own spindle cable as the connector was non-standard
- Using a CPU cooler as a pump isn't sufficient. I both a CW3000 and it's fantastic
- I had to replace my drag chains to handle the extra cables

I love it; it's more than enough power for the things I cut. And it'll cut aluminum too

[olf20]

Thanks for all the replies! I'm still not sure which
way I will go.
I do have the room for coolant tank.
I do use 1/2" shank bits for some projects but mostly
1/4".
Thanks again guys!
olf20 / Bob