[KiwiEngineer]

Kia ora!

Ive been exploring this wonderful forum gathering information before i start my build.

I will be casting a gantry type cnc router with approximate build volume of 700mm x 500mm x 150mm out of cast iron from a local foundry.

I will be primarily cutting Aluminum, but of coarse i aim to try cut Steel. I am based in NZ and only have single phase electricity.

Can anyone help me choose the best spindle for this sort of application? I have found these 2 so far which i think will be good contenders as they are both 4 pole.

https://www.aliexpress.com/item/3298...archweb201603_

or

https://www.aliexpress.com/item/4001...archweb201603_

I have to admit im a little confused between the 2 as one is 800hz and one is 400hz. Which one would be better at low RPM?

I also noticed that the GDK80-12Z/2.2 spindle claims 1500 - 12000rpm in the link below. But doesnt claim it in the above link.

https://www.aliexpress.com/item/4000...%2315609%23235

Cheers,

Rohan

[GoodTimesDesign]

Looking for the same recommendation.

[Dean448]

I use a similar water cooled 220v spindle for wood and am sure it will cut certain types of aluminum. It runs up to 400hz.
Steel cutting requires far lower speeds and much higher torques. Spindle and machine stiffness are much higher when cutting steel.
So I don’t think this spindle will actually cut steel, other then fine finishing. If that’s not what you intend to do, I would try to find torque specifications on these spindles at lower speeds.


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[mactec54]

Kia ora!

Ive been exploring this wonderful forum gathering information before i start my build.

I will be casting a gantry type cnc router with approximate build volume of 700mm x 500mm x 150mm out of cast iron from a local foundry.

I will be primarily cutting Aluminum, but of coarse i aim to try cut Steel. I am based in NZ and only have single phase electricity.

Can anyone help me choose the best spindle for this sort of application? I have found these 2 so far which i think will be good contenders as they are both 4 pole.

https://www.aliexpress.com/item/3298...archweb201603_

or

https://www.aliexpress.com/item/4001...archweb201603_

I have to admit im a little confused between the 2 as one is 800hz and one is 400hz. Which one would be better at low RPM?

I also noticed that the GDK80-12Z/2.2 spindle claims 1500 - 12000rpm in the link below. But doesnt claim it in the above link.

https://www.aliexpress.com/item/4000...%2315609%23235

Cheers,

Rohan

The G-Penny is the best spindle you have picked 400Hz verse 800Hz

800Hz 4 pole would be able to go up to 24,000 RPM

400Hz 4 Pole would only be able to go up to 12,000 RPM 400Hz 2 Pole will go to 24,000 RPM

The VFD Drives offered are not a good choice of VFD Drives to use so would buy the spindle separate

None of these spindle are suitable to mill steel, anything up to aluminum will be fine, you can do steel engraving though

[KiwiEngineer]

Hi Mactec54,

Thanks for the info!

Would you have a VFD you would recommend?

Is the main reason these are not suitable because of the peak torque being such a high speed or the build quality and bearings are not suitable?

Rohan

[mactec54]

Hi Mactec54,

Thanks for the info!

Would you have a VFD you would recommend?

Is the main reason these are not suitable because of the peak torque being such a high speed or the build quality and bearings are not suitable?

Rohan

I think you are talking about the milling of steel =Bearings, the Bearing arrangement and spindle design is the main problem, not the Bearing quality, High speed spindles built as cheap as these are have the 2 front AC Bearings with the cup facing out, the 2 top bearings are facing the opposite direction which are spring loaded, so as the spindles loads get higher, the front Bearing come off there faces of the AC Bearings and will chatter like mad until a thrust loading is applied

If you look at the G-penny you get more torque than any of the other spindles with the same Kw rating, because of the rotor is longer and a larger diameter, there is more copper in the stator plus if you see the Amp specs is also higher

The minimum speed is also better because of there design 3000 RPM all other water cooled are 6,000 RPM minimum

There are other seller selling this same spindle, under a different name, but be careful as there are some that look the same but are not

VFD Drive would depend on what Hz you went with the are many good VFD Drives for the 400Hz spindles not so many for the 800Hz to choose from

For what you want to do I would go with there best one with the Steel core, ceramic Bearings, the regular spindle has aluminum core

[KiwiEngineer]

Cheers again for the info!

I guess this seems like what im after.

https://www.aliexpress.com/item/4000...archweb201603_

As im not too concerned about 24k rpm and i think 12k should be plenty. I think a good 400hz would do me just fine.

I notice these seem to be very popular. I guess it isnt because their so cheap.

https://www.aliexpress.com/item/1689...5a1c1e74KMlqZQ

Rohan

[mactec54]

Cheers again for the info!

I guess this seems like what im after.

https://www.aliexpress.com/item/4000...archweb201603_

As im not too concerned about 24k rpm and i think 12k should be plenty. I think a good 400hz would do me just fine.

I notice these seem to be very popular. I guess it isnt because their so cheap.

https://www.aliexpress.com/item/1689...5a1c1e74KMlqZQ

Rohan

Correct the 4 pole 400Hz is all that most need unless you are using very small diameter cutters then the extra spindle speed can be a good thing

With that VFD Drive yes it is one of the most popular in the 400Hz range, for single phase, go a little larger so like 3Kw you will want a 25A / 30A circuit for your machine power supply

[KiwiEngineer]

Thanks again for the fast response! As i have already made the purchase and they were trying to change my order. (which is nice they are thinking of me)

I had chosen the following.

https://www.aliexpress.com/item/1005...61b64c4druejlj

and

https://www.aliexpress.com/item/4000...61b64c4druejlj

Which from what i understand should work fine being. But would only run at 12k rpm max? Which i am more then happy with.

So i should reply back to the support and ignore there suggestion and carry on with my order?

Rohan

[mactec54]

Thanks again for the fast response! As i have already made the purchase and they were trying to change my order. (which is nice they are thinking of me)

I had chosen the following.

https://www.aliexpress.com/item/1005...61b64c4druejlj

and

https://www.aliexpress.com/item/4000...61b64c4druejlj

Which from what i understand should work fine being. But would only run at 12k rpm max? Which i am more then happy with.

So i should reply back to the support and ignore there suggestion and carry on with my order?

Rohan

The spindle you have the link to is 800Hz this will not run with the 400Hz VFD Drive

[KiwiEngineer]

ahh right. I guess i didnt understand correctly..

Would it be easier to find a better VFD or to find a 4 pole 400hz spindle?

Rohan

[mactec54]

ahh right. I guess i didnt understand correctly..

Would it be easier to find a better VFD or to find a 4 pole 400hz spindle?

Rohan

There are not a lot of choices in the cheaper VFD Drives, that do 800Hz, the one they offer Fuling is border line but will do the job, for the 800Hz spindle, it is a little low in power rating for single phase use, the best VFD Drives are expensive Yaskawa Delta Etc. the next up Fuling is 3.7Kw this would be better but make sure it has 800Hz or more in the spec's if you buy this one

I thought the spindle you had found was 400Hz 4 Pole

[KiwiEngineer]

I dont mind spending more to get a better VFD. But i cant find any any delta,yaskawa or hitachi VFD's that will output 800hz. Do know any of the better models that will do this?

The fuling VFD's seem a little miss leading in there title as they claim 10A output for the 2.2kw and 15A output for the 3.7kw in their descriptions.

What is the physical difference between and 4 pole 400hz spindle and a 4 pole 800hz one?

Rohan

[mactec54]

I dont mind spending more to get a better VFD. But i cant find any any delta,yaskawa or hitachi VFD's that will output 800hz. Do know any of the better models that will do this?

The fuling VFD's seem a little miss leading in there title as they claim 10A output for the 2.2kw and 15A output for the 3.7kw in their descriptions.

What is the physical difference between and 4 pole 400hz spindle and a 4 pole 800hz one?

Rohan

There would not be any physical difference between the 2 spindles inside will be different, there is always conflicting numbers in there description's

This is a Delta VFD11AMS21ANSHA High speed Model and Yaskawa the best of all but a high cost V1000 High speed model

Yes you have to put in High speed when you try and find these VFD Drives, then you will get the spec's for that VFD Drive the Delta High speed goes up to 1500Hz

The Delta will be better priced of these 2 VFD Drives

[joeavaerage]

Hi,
I've found that high speed low torque spindles are very poor choices for milling steel.

You can engrave, light finish cut with small diameter (3mm or less) endmills but that's it.

I made a second spindle especially for steel. I used a 1.8kW Allen Bradley servo (3500rpm/6.2Nm cont) and
cylindrical ER25 toolholder and P4 angular contact bearings. Just the 'bees knees' in steel.

The majority of time (90%) I use my highspeed spindle and only swap over to the 'grunter' when I need it.

Where-abouts in NZ? I'm just out of Christchurch.

Craig

[mactec54]

Hi,
I've found that high speed low torque spindles are very poor choices for milling steel.

You can engrave, light finish cut with small diameter (3mm or less) endmills but that's it.

I made a second spindle especially for steel. I used a 1.8kW Allen Bradley servo (3500rpm/6.2Nm cont) and
cylindrical ER25 toolholder and P4 angular contact bearings. Just the 'bees knees' in steel.

The majority of time (90%) I use my highspeed spindle and only swap over to the 'grunter' when I need it.

Where-abouts in NZ? I'm just out of Christchurch.

Craig

He has a 4 pole not a 2 pole motor, the 4 pole motor is much better so has some ability to mill steel still not the greatest, what he has is not the normal 6,000 to 24,000 spindle

[KiwiEngineer]

He has a 4 pole not a 2 pole motor, the 4 pole motor is much better so has some ability to mill steel still not the greatest, what he has is not the normal 6,000 to 24,000 spindle

Another dumb question incoming haha.

I cant seem to find the physical difference inside between a 800hz spindle and 400hz one. I thought i could possibly get G-Penny to modify my one? Would this this benefit me how? Or would it have the same torque curve at the same rpm as the 800hz spindle but with a lower top speed?

Rohan

[KiwiEngineer]

Hi,
I've found that high speed low torque spindles are very poor choices for milling steel.

You can engrave, light finish cut with small diameter (3mm or less) endmills but that's it.

I made a second spindle especially for steel. I used a 1.8kW Allen Bradley servo (3500rpm/6.2Nm cont) and
cylindrical ER25 toolholder and P4 angular contact bearings. Just the 'bees knees' in steel.

The majority of time (90%) I use my highspeed spindle and only swap over to the 'grunter' when I need it.

Where-abouts in NZ? I'm just out of Christchurch.

Craig

Hi Craig,
As Mactec54 said ive brought a 4 pole spindle which from what i understand is "double" the torque. So giving it a go anyway, will at least be good for cutting plastic and light cuts of aluminium.

Do you have anymore information about your custom spindle? Might have to go down the route in the end haha.

Im based in Tauranga.

Rohan