[mactec54]

They list the PC at 3 1/4 hp. You can hear the rpm drop a bit when cutting so probably getting less then full hp? I had heard the spindles maintain rpm better, more torque, so more hp when cutting, is that true? If so then it sounds like the 2.2kw would be a close replacement unless I'm missing something? Or would the 3.5kw give a machine more ability? I know it's hard to make specific recommendations when you don't know my machine.

Yes bigger is always better the big question though, is the machine going to be able to make use of the extra power, if you are only using 1/4" cutters then the 2.2Kw is enough if bigger cutters are used then go with the 3.5Kw

Be careful with the VFD Drive selection all are not created equal, so some of the package VFD Drive deals are not ideal

[planebuilder]

Mactec54, Thanks for your advice and time! I will narrow the search next week and if you don't mind, get your opinion on the drive I select.

[planebuilder]

I'm finally back and ready to buy a spindle. I am looking at a G-Penny 3.2kw spindle & inverter kit.
https://www.aliexpress.com/item/3294...000416871118.4
It said it's for wood work, but you can select ceramic bearings, does that make it ok for aluminum?
You had said some inverters in the package kits are not best, is this one ok? Or should I order a different inverter separately.
Do I understand correctly that 800hz will have more torque than 400hz? The 800hz ones I found needed 3ph input, I only have 1ph 220V.

Any opinions appreciated.

[servtech]

I'm finally back and ready to buy a spindle. I am looking at a G-Penny 3.2kw spindle & inverter kit.
https://www.aliexpress.com/item/3294...000416871118.4
It said it's for wood work, but you can select ceramic bearings, does that make it ok for aluminum?
You had said some inverters in the package kits are not best, is this one ok? Or should I order a different inverter separately.
Do I understand correctly that 800hz will have more torque than 400hz? The 800hz ones I found needed 3ph input, I only have 1ph 220V.

Any opinions appreciated.

For the same motor, ie 1400rpm at 50hz
400hz is 8 X 1400 = 12,000rpm spindle
800hx is 16x 1400 = 24,000rpm spindle

Ceramic balls are more suited to 24000
And 12,000 steel with fibre cage.

Higher rpm's normally means lower torque power curve. 12,000 more suited to aluminium.

[planebuilder]

12,000 sounds slow, I normally cut aluminum at 20,000 RPM, 100 imp, .063" thick, 6061T6.

[joeavaerage]

Hi,

12,000 sounds slow, I normally cut aluminum at 20,000 RPM, 100 imp, .063" thick, 6061T6.

The actual spindle speed is less relevant than the surface speed of the tool in the material.

Uncoatded carbide tools in med tensile aluminum like 6061 the recommendation is 200m/min up to 500m/min, so a big range. If you want to use the highest surface speed then you'll almost
certainly want cooling.

6mm at 20,000rpm=377m/min
10mm at 12000rpm=377m/min
so both are equivalent surface speed. Now you have to decide on chip thickness and that will largely determine the torque and power.

I run 6mm tools in aluminum at 12000 to 15000, mainly to avoid heat build up. My spindle is only 800W so I have to take it fairly carefully, although you can go too slow and just 'rub the aluminum',
a sure way to stuff it up.

Craig

[mactec54]

Ceramic balls are more suited to 24000
And 12,000 steel with fibre cage.

Ceramic Bearings are suitable for any RPM range, they just cost a little more, have a higher loading and smoother running, than any steel Ball Bearing, and they last 3 to 4 times as long.

[planebuilder]

mactec54, I was hoping you would respond, I have a few questions for you if you don't mind.

copied from previous post so you don't have to go find it,

I'm finally back and ready to buy a spindle. I am looking at a G-Penny 3.2kw spindle & inverter kit.
https://www.aliexpress.com/item/3294...000416871118.4
It said it's for wood work, but you can select ceramic bearings, does that make it ok for aluminum?
You had said some inverters in the package kits are not best, is this one ok? Or should I order a different inverter separately.
Do I understand correctly that 800hz will have more torque than 400hz? The 800hz ones I found needed 3ph input, I only have 1ph 220V.

[mactec54]

I'm finally back and ready to buy a spindle. I am looking at a G-Penny 3.2kw spindle & inverter kit.
https://www.aliexpress.com/item/3294...000416871118.4
It said it's for wood work, but you can select ceramic bearings, does that make it ok for aluminum?
You had said some inverters in the package kits are not best, is this one ok? Or should I order a different inverter separately.
Do I understand correctly that 800hz will have more torque than 400hz? The 800hz ones I found needed 3ph input, I only have 1ph 220V.

Any opinions appreciated.

You have 240v Single Phase not 220v.

You can only run these spindles with a VFD Drive which can use 1ph / 240v input and will give you 3ph output to drive these spindles.

No, it will not have more torque than a 400Hz spindle, it depends on the design, the 800Hz could have less torque, if the Base speed, for a 4Pole is 12000 / 400Hz, then at 800Hz for 24,000 the torque would be less.

Most use the 2 Pole 400Hz 24,000 RPM spindle for normal use, this will have half the torque at 12,000 RPM 200Hz.

[joeavaerage]

Hi,
ceramic bearings/steel bearings is a bit of a storm in a teacup. Good P4 grade bearings, be they steel or ceramic, will have low runout and work fine.
The extra cost of ceramic bearings is if you expect very long life. Some high speed, say 30,000, 36,000 and 42,000 rpm spindles really benefit from ceramic
bearings, and most are offered as standard in the higher rpm's.

If either the 2 pole OR the 4pole motor had any extra torque at say 12000 rpm that would be nice, but probably little or no difference. 800Hz VFD's are a little harder to find
whereas 400Hz and 600Hz VFD's are the norm.

Craig

[joeavaerage]

Hi,
a friend is an electrician in a large printing business. The multi-million dollar press was breaking down often because the steel bearings were failing in the servos.
This was a near new machine. Eventually the German engineers came out to have a look and found that there was some residual electrical current passing from the armature through
the steel bearings and causing accelerated wear. The Germans all went home and sent out a whole bunch of ceramic bearings that my friend had to fit. It took him months to get around
all of them, and send the bill to the German manufacturer. One of the few times a Kiwi can stick it to a German engineering company!

Craig

[planebuilder]

Thanks Mactec54, and Joeavaerage, one last (maybe) question.
You had said some inverters in the package kits are not best, is the one in this package ok? Or should I order a different inverter separately.

[joeavaerage]

Hi,
VFDs range in quality and in some cases capability. 'Sensorless Vector' capable VFDs are a more sophisticated design over the earlier V/F design. Most good VFD's will be able to do both.

I've always bought Delta VFDs, a Taiwanese brand made in China. They work well, have good support and documentation, and highly reliable....but they are not the
cheapest. Another brand that has a good reputation for quality at affordable prices is Hitachi. There are plenty of cheaper Chinese brands but I don't not have any recommendations
other than most people seem to get a good run out of them, then again some don't too.

One thing that kills more VFDs than anything else is hooking up your spindle and attempting to run it direct from the factory. The spindles you are interested in are at the very least 400Hz
and yet the VFDs are usually set up for 50Hz or 60Hz motors direct from the factory. You must program or at least confirm the programming of the VFD before you attempt to run it
or the smoke will leak out.

Craig

[peteeng]

Hi Craig - You say you run 6mm tools at 12k to 15k for aluminium. What feed rate do you use? for 100% width cut? or what chip thickness do you aim at? and 1F or 2F tools? Peter

[joeavaerage]

Hi peteeng,
the tools are three flute, nothing special, from a local merchant.

I try to run at about 600mm/min-900mm/min which results in chips of 1um to 4um. To run slower tends to just 'rub' the material which is no good at all, and running faster means I have to back off the depth
and/or width of the cut. Its very easy to overwhelm a 800W spindle, especially at half speed! The depth of cut and stepover I adjust to give a comfortable load on my spindle.

If I use a 1/8" tool, that I'l run at 24000rpm with coolant. With a sharp tool and plenty of coolant you can start removing good amounts of metal and the spindle is at its most powerful.

My spindle is only 800W and air cooled and I use it daily for making circuit boards and have been doing so for years. I just cannot afford to blow it up, it makes me a living! I treat it
carefully. If I have something that I really need to bore into I use my second spindle (1.8kW, 6.1Nm cont, 3500rpm) with bigger tools. I can really get in amongst it, and if I blow it
up it does not screw my income.

Craig

[mactec54]

Hi,
a friend is an electrician in a large printing business. The multi-million dollar press was breaking down often because the steel bearings were failing in the servos.
This was a near new machine. Eventually the German engineers came out to have a look and found that there was some residual electrical current passing from the armature through
the steel bearings and causing accelerated wear. The Germans all went home and sent out a whole bunch of ceramic bearings that my friend had to fit. It took him months to get around
all of them, and send the bill to the German manufacturer. One of the few times a Kiwi can stick it to a German engineering company!

Craig

This is very common in any Servo or VFD Driven AC motor, this is not something new, the Bearing are damaged by Rotor Voltage / current passing through the Bearings that is one of the reasons to use Ceramic Bearings if they are offered for these Spindles. this snip shows you what happens to all VFD Drive driven AC Motors, and it is even worse when you used an unbalanced Power supply single phase to 3phase.

[peteeng]

Cl=750/12000/3=0.021mm that's a small chip thickness for aluminium? nearly a rub. Most data says run at 0.08 to 0.12mm? even 0.15mm have you tried less edges and faster? Peter a 1% cut is 0.06mm and that's light for 6mm tool. Just looking at a guhring chart and for a 6mm 1F they quote a mm/z of 0.04mm at a surface speed of 300m/min....Peter

[planebuilder]

Mactec54, sorry to keep bugging you , but you seem to know a lot about these, and I don't. You said

"Be careful with the VFD Drive selection all are not created equal, so some of the package VFD Drive deals are not ideal"

Do you know if the Huanyang 220V 4.0kw drive is ok, or should I order a different drive seperatly from G-Penny?

It is with this package
https://www.aliexpress.com/item/32945024944.html?spm=a2g0o.store_pc_groupList.8148 356.1.5b3c4e59oy5Umm&pdp_npi=2@dis!USD!US%20$448.59!US%20$349.90!!!!!@2 108725416737610132197761eda7d!66292584640!sh&gatewayAdapt=4itemAdapt&spm=a2g0o.store_pc_home.hotSpots_6000416871118.4

[mactec54]

Mactec54, sorry to keep bugging you , but you seem to know a lot about these, and I don't. You said

"Be careful with the VFD Drive selection all are not created equal, so some of the package VFD Drive deals are not ideal"

Do you know if the Huanyang 220V 4.0kw drive is ok, or should I order a different drive seperatly from G-Penny?

It is with this package
https://www.aliexpress.com/item/32945024944.html?spm=a2g0o.store_pc_groupList.8148 356.1.5b3c4e59oy5Umm&pdp_npi=2@dis!USD!US%20$448.59!US%20$349.90!!!!!@2 108725416737610132197761eda7d!66292584640!sh&gatewayAdapt=4itemAdapt&spm=a2g0o.store_pc_home.hotSpots_6000416871118.4

Yes, that is the correct size for that spindle make sure you get the 220v model if your supply power is 240v, for once they have it right, they have sized that for single phase use.

You do have a 40A supply circuit for your whole machine, if not this Spindle will not work very well.

[planebuilder]

Thank you very much, and yes I have 40 amps available to the machine.