Chinese high speed spindle for metal milling

Hello everyone. I'm doing some research on spindles for a small mill.

Mostly for aluminium work, but has to be able to do steel as well.

So. Looking at aliexpress to see what is available there I've found two 18000rpm spindles with ER32.

One with square housing which the seller say is for woodworking and light metals, but not for steel.
The other is round and the seller says it is for metal.

As far as I can see there are little difference. The bearings ie. is the same in both. The metal spindle is heavier.


Wood:
https://www.aliexpress.com/item/3283...chweb201603_53
Metal:
https://www.aliexpress.com/item/1810...chweb201603_53


What do you think. Will either of these spindles survive light milling in steel (using smaller end mill is ok). Low speed power is not that good so it has be light either way.

I guess both is fine for aluminium and ligher metal work and the top speed is nice for high speed milling.

Quote:

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Originally Posted by Buoyen

Hello everyone. I'm doing some research on spindles for a small mill.

Mostly for aluminium work, but has to be able to do steel as well.

So. Looking at aliexpress to see what is available there I've found two 18000rpm spindles with ER32.

One with square housing which the seller say is for woodworking and light metals, but not for steel.
The other is round and the seller says it is for metal.

As far as I can see there are little difference. The bearings ie. is the same in both. The metal spindle is heavier.


Wood:
https://www.aliexpress.com/item/3283...chweb201603_53
Metal:
https://www.aliexpress.com/item/1810...chweb201603_53


What do you think. Will either of these spindles survive light milling in steel (using smaller end mill is ok). Low speed power is not that good so it has be light either way.

I guess both is fine for aluminium and ligher metal work and the top speed is nice for high speed milling.

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I don't think either of these 2 would be suitable for cutting steel, it would depend on how the Bearings are arranged in the nose of the spindle

Most are preloaded by the Top Bearings in the spindle which makes them unsuitable for milling steel, engraving steel is not normally a problem,for any of them but machining steel is a different story, light machining with small cutters you most likely can do but don't expect anything great

With this Bearing arrangement the front 2 bearings have the cup of the AC bearing facing outward, so load up on the spindle is ok, but a cutter like a End mill try to pull down which can take the preload off the front bearings and cause a bad finish on your work and over time damage the Bearings

Also you have to watch the Kw rating, always more is better, but do you have the Power supply to run it

Very nice mactec, thank you!
Haven't really thought about the preload and possible differences.

But I think maybe it will be sufficient for my application. Yes I will try to find the smallest motor power rating I can.

Do you think these BT30 cartridges are better? But the total setup will be quite expencive also for a high speed type:
US $1,090 | high speed ATC BT30 automaitc spindle for cnc machine / cutting machine 12000rpm
https://s.click.aliexpress.com/e/3rnpXgss

+1 for everything mactec54 said.

Can you be more specific about what type of metal cutting you want to do, what is the smallest and largest cutters you want to use in steel?

I was looking for a spindle recently, and settled on this:
https://www.aliexpress.com/item/3287...27424c4d5mbtqP

only because I couldn't afford this:
https://www.aliexpress.com/item/2047...c00jAwLrI&mp=1

It would be nice to run a 40-50mm face mill or fly cutter on aluminium. Also facing with a 12-16mm end mill will on steel.

If I can use 6-8mm end mills on steel I think I'll be satisfied. They are stiff enough so I can have stickout for pockets etc.

That er16 looks nice but maybe a bit low speed rating.. but I'm used to small cutters and high rpm when doing aluminium on my router :)

Quote:

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Originally Posted by Buoyen

Very nice mactec, thank you!
Haven't really thought about the preload and possible differences.

But I think maybe it will be sufficient for my application. Yes I will try to find the smallest motor power rating I can.

Do you think these BT30 cartridges are better? But the total setup will be quite expencive also for a high speed type:
US $1,090 | high speed ATC BT30 automaitc spindle for cnc machine / cutting machine 12000rpm
https://s.click.aliexpress.com/e/3rnpXgss

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Yes any cartridge like this has a Bearing arrangement that is suitable for normal milling of anything you want to mill, it then becomes a problem as to what are you going to run that spindle cartridge with how you can mount it rigidity of your mounting added weight to your Z axes Etc.

I doubt you'd be even close to those rpm's for steel.
There's 1.8kw 6nm and above servos for that kind of stuff on a mill.

For this sort of a machine; when you are doing your CAM, I would suggest tending to favor "high-speed-machining" strategies; as these tend to result in lower spindle torque loads (obviously, however, don't use the same feed & DOC that you'd use on a big VMC - your machine won't have the same HP at the RPMs required; nor will it have the same rigidity). Also probably obvious, but you will want carbide tooling; not HSS, due to the RPMs involved. Coolant, of course, is a must; either a fog-buster spray style or if your machine is fully enclosed flood coolant might be an option.

Also note that those spindle cartridges do not have a motor integrated into them; so be sure to plan for that. There also does not appear to be a way to actuate the drawbar; it may include the belleville washers or some other spring to hold the tool in the spindle; but I think you will need to add an air cylinder or some other mechanism to get the tool to release.

:)

Thanks everyone. I'm using F360 adapttive clearing when I can which should be HSM toolpath and G-wizard for feeds and speeds on my router (have entered dimensions, weight, spindle power etc into GW to get numbers for my machine). Works really good.

Discovered this guy has built a setup with a lever to compress the springs in the BT30 unit for tool change:
https://youtu.be/cK8GqIieLMY

That could make the BT30 setup a little bit cheaper at first and make it possible to change to pneumatic later.

Also looked into Hertz brand spindles (ER collets). Hertz Spindle Motors – Ultimate Spindle Motors
Looks promising and for me in europe at least they can compete with the chinese ones on price.

However I discovered they do not recommend steel bearings for radial load aplications. They offer a setup with cermaic bearings but at twice the price. Is that necessary?

I thought the primary advantage of ceramic over steel was higher rotational speed for the bearing size. But maybe the ceramic bearings can have more preload?

Quote:

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Originally Posted by Buoyen

Discovered this guy has built a setup with a lever to compress the springs in the BT30 unit for tool change:
https://youtu.be/cK8GqIieLMY

That could make the BT30 setup a little bit cheaper at first and make it possible to change to pneumatic later.

Also looked into Hertz brand spindles (ER collets). Hertz Spindle Motors – Ultimate Spindle Motors
Looks promising and for me in europe at least they can compete with the chinese ones on price.

However I discovered they do not recommend steel bearings for radial load aplications. They offer a setup with cermaic bearings but at twice the price. Is that necessary?

I thought the primary advantage of ceramic over steel was higher rotational speed for the bearing size. But maybe the ceramic bearings can have more preload?

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Ceramic Bearing have very little to do with just a speed advantage, if they are just using Ceramic Ball they are superior over steel balls in every way, unless they are building the Bearing arrangement in the Spindle different to the steel Bearing Spindle I think they are talking Bs, Ceramic are better but if they are built the same, ( assembled the same ) then the steel Bearing Spindle will work just as well but they won't last as long

Okey, cool. Thank you!