[joeavaerage]

Hi,
my calculation was for STEEL....not aluminum. And I based it on a target surface speed of 100m/min which is about right for uncoated carbide in steel and maybe 150m/min for coated carbide.
Plenty of people push that out to 200m/min trying to save time but being harder on tools.

With aluminum surface speeds can be anywhere from 250m/min to 500m/in, so about 2.5 to 5 times what I calculated for steel and if cycle time is more important than tool life you can push it more.


The problem that OP faces is that these spindles have low torque and that's not a good recipie for big diameter tools.

Craig

[mactec54]

Hi,
my calculation was for STEEL....not aluminum. And I based it on a target surface speed of 100m/min which is about right for uncoated carbide in steel and maybe 150m/min for coated carbide.
Plenty of people push that out to 200m/min trying to save time but being harder on tools.

With aluminum surface speeds can be anywhere from 250m/min to 500m/in, so about 2.5 to 5 times what I calculated for steel and if cycle time is more important than tool life you can push it more.


The problem that OP faces is that these spindles have low torque and that's not a good recipie for big diameter tools.

Craig

Even in steel with a modern tooling 2,800 RPM Plus is my speed for a 3" Lovejoy face mill.

The cutters I post are designed for these spindles and run at 8,000 RPM to 12,000RPM so are perfect for the 12,000RPM 400Hz spindle the 12,000RPM spindle has full torque at the listed 12,000RPM

[Waynekofuco]

That is a ridiculous RPM number you have posted, I run, and most machinists run 2" to 3" face milling cutters from 2,800 RPM to 4,000 RPM for aluminum machining.

These Amana Face Mills run from 8,000 RPM to 12,000 RPM which are suited for these spindles controlling cut depth is important, choosing the right Tooling is important too.

https://www.amanatool.com/products/i...-x-1-4-inch-sh

https://www.amanatool.com/rc-3400-cn...outer-bit.html

Ah perfect thanks for the links. I looked at similar bits but the were wood only for the 12000. Thanks great find

[crjohnson]

For what its worth: I run one of these BAP400R style face mills, 50mm diameter, 12mm shank (for ER20 collets) at approx. 9000RPM (300Hz) on my spindle. I could possibly go slower but haven't pushed my spindle into the lower RPM range yet.

I only do 0.1mm-0.15mm deep cuts and 25-50mm wide, 600mm/min feedrate. It initially cut very nice using carbide inserts then I changed to PCD inserts and its like mirror 99% of the time.

https://www.aliexpress.com/item/1005...26841993.pic_0

https://www.aliexpress.com/item/1005...59101802N2Yg65

[Waynekofuco]

For what its worth: I run one of these BAP400R style face mills, 50mm diameter, 12mm shank (for ER20 collets) at approx. 9000RPM (300Hz) on my spindle. I could possibly go slower but haven't pushed my spindle into the lower RPM range yet.

I only do 0.1mm-0.15mm deep cuts and 25-50mm wide, 600mm/min feedrate. It initially cut very nice using carbide inserts then I changed to PCD inserts and its like mirror 99% of the time.

https://www.aliexpress.com/item/1005...26841993.pic_0

https://www.aliexpress.com/item/1005...59101802N2Yg65

It just so happens I orderd this for my ISO20 spindle a couple days ago.
https://www.aliexpress.us/item/32568...andl_shipto=US

What spindle are you using?

[crjohnson]

Jianken JGH105/2.2kw, 400-800Hz, 4 pole, ER20

[Waynekofuco]

Ah yes, I checked right after I posted. Are you having noise issues w your spindle?
I got another update from Wafer and they now have the JGL100/2.5kw like Fox's in BT30...

[crjohnson]

No it all seems to be back to normal now. I think it needed some time to warm up that day. Otherwise I emailed Wafer (a while ago now!) about what grease to use if I was to strip, clean and regrease the spindle at some point.

[mactec54]

No it all seems to be back to normal now. I think it needed some time to warm up that day. Otherwise I emailed Wafer (a while ago now!) about what grease to use if I was to strip, clean and regrease the spindle at some point.

The best type of Grease to use for Spindle Bearings Kluber IsoFlex NBU15, when Greasing a High-Speed Bearings like this, it needs to be a measured amount per Bearing.

I doubt that you would be striping the spindle down to clean the Bearings and regrease, by the time you need to do this the Bearings will be done and need replacing, you can calculate the Bearings life, using specs from any major Bearing Manufacture, plus find the measured Grease quantity required.

The Bearing used in your Spindle are most likely Sealed as most of these Spindles from Chinese manufacturers are, so are factory Grease filled by the Bearing Manufacture, not Greased by the Spindle Manufacture, so if they are sealed Bearings then Jianken would have no clue as to what Grease is used for the Spindle Bearings.

[crjohnson]

Thanks Mactec, they have the following listing but don't tell you what size is inside each spindle. I may order a spare set just in case they're ever needed.

https://www.alibaba.com/product-deta...41a63b975AWh1I

[Waynekofuco]

Thanks Mactec, they have the following listing but don't tell you what size is inside each spindle. I may order a spare set just in case they're ever needed.

https://www.alibaba.com/product-deta...41a63b975AWh1I

Keep us posted if you do source replacement bearings. If I order another Jainken Ill ask for a ceramic set as well. Though I don't know if I would have the skills/tools to replace them by myself...

Im thinking the JGL100/2.5-BT30 is the way to go, but still not sure about the 2/4pole setup.

[Waynekofuco]

I settled on the JGL100/2.5-BT30 4 pole, Thanks for all the input.

[Waynekofuco]

I rec'd the new spindle, pretty crazy the size difference of the spindle and the tooling. I won't be able the test the new spindle until I get the head stock sorted.
JGL-80 2.2kw 400hz ISO20 vs
JGL-100 2.5kw 800hz ISO30

[crjohnson]

Looks good! The more machining I do lately the more I wish I had ATC. Even just setting up the probe to locate features is slow with the ER20. The probe always needs adjusting..

[joeavaerage]

Hi,
second that.

I do a lot of very small parts and even more circuit boards using isolation routing. I'd dearly love an ATC spindle. It does not need to be powerful, my 24000rpm 800W spindle is fine as is, but
life would be so much better with a twenty tool carousel.

Of course ideally I go faster than 24000rpm and that would sort of indicate an HSK tool interface....all of which is possible just increasingly expensive.

Craig

[joeavaerage]

Hi,
that new spindle does not look that much bigger....but surprise, surprise very nearly double the weight. Sort of makes you think you've got the 'real deal' now.

Craig

[fpbfpb]

Hi,

G-Penny on aliexpress is selling two (different ?) 2.2kw 4 poles spindle for metal.
one is 4p, 400hz, 6000-12000rpm, 1.75Nm other is 4p, 800hz, 9000-24000rpm, 0.88Nm.
same size same power same weight.

is there real mechanical / electrical differences or just the way to drive them ?

fuling (folinn) H1 vfd seems to be vector control up to 1000hz with custom V/f curve even in vector control mode.
witch G-Penny spindle do you think is the best one to be normally drive up to 400hz and then in constant power mode up to 800hz ?
why not full power from 0hz to get maximum torque all over the frequency range ?
is the over heat a problem on a water cooled spindle ?

thanks a lot

[joeavaerage]

Hi,

is there real mechanical / electrical differences or just the way to drive them ?

Like almost all electrical motors the torque output is dependent on current.

In the case of 4P motor, with lets say 1A in each of the coils and it produces 4Nm. The same motor but with 8P (the same number of turns etc) and the same 1A in each coil
the you'd get 8Nm. That's great, more torque, so why not add more coils....but to add extra coils means that you have to use thinner wire to make the coils smaller and thereby fit more in. The smaller coils
can take less current without overheating, lets say or 8P motor from above can only take 0.5A per coil, then it would produce 4Nm torque.

Each coil will generate a voltage as the motor spins. It opposes the current supplied by the VFD. The faster the motor spins the more the BackEMF. Eventually the BackEMF is the same as the voltage
output of the VFD and the motor can go no faster. If you joined your 8P windings in series the it will have really good torque for a small amount of current, very desirable, but the BackEMF will be higher
so for a given voltage VFD it will go slower. Alternately if your wired your 8P windings in two groups of four in series with the two groups in parallel then for the same current you get half the torque,
but the BEMF is now half and so you can go twice as fast for the same VFD.

Really there is little difference between the two motors, just how the coils are wound and arranged. Some CNCers want best possible torque for a given size motor, while others want max rpm.
Some CNCers want max torque and max speed, and I suggest they write to the Tooth Fairy to get one. Last I heard he was flatting with the Easter Bunny, smoking a lot of weed and bonking
all the girls.

Craig

[fpbfpb]

Hi,

Thank you for the explanation.

I very would like to experiment if a G-Penny spindle is able to match The Mechatron HFPM-8022-24-ER20.
You said there is little differences on SAME SIZE / SPECS spindle so I doubted Chinese manufacturers are not able to match the Mechatron, maybe "made in china" it self.
The G-Penny is a bit longer (more space for coils), same diameter, same weight, same nb of poles, same voltage, same power.
Because of these similarities and my wish to match it, not to beat it, no need to ask the Tooth Fairy here is the place to ask :)

Which G-Penny spindle, 400hz 12K or 800hz 24K, would you choose to drive it (full power 2.2kw from 400hz to 800hz) like the Mechatron and try to match it ?

I did notice that the Mechatron torque up to 400hz is the same as the G-Penny 400hz 12K and the Mechatron torque at 800hz is the same as the G-Penny 800hz 24K.
Curves of the two G-Penny and the Mechatron in attachments.

Regards

PS: I very would like to know if it can be done, but not to the point to buy both.

[joeavaerage]

Hi,
which one depends really on the sort of work you want to do with it.

My choice would be for a spindle that has more torque at lower speeds, so that it could be used for steel, but retain as much high speed as possible for aluminum and engraving.
The Mechatron does that nicely, it as 1.6Nm of torque up to its 'rated speed' of 12000rpm and has constant power (ie reducing torque) from 12000rpm to 24000rpm. You might
say the best of both worlds.

The 12000pm GPenny has good torque (as good as the Mechatron), but is not characterized for speeds above 12000rpm. Its probably not recommended but I be prepared to bet that if you had a VFD
that could produce higher frequencies then you could push this spindle to 24000rpm.

Just because the Mechatron and the GPenny 12000rpm have better torque at lower speeds still does not really make them 'steel spindles'. Sure, they have more capability
to do steel but they are a long way from perfect for steel either.

The 24000rpm GPenny is rated for 24000rpm but naturally has lower torque (0.8Nm).

All three spindles are useful. The 24000rpm GPenny would be best for continuous high-speed work whereas the 12000rpm GPenny would be better for slower speeds, but could when pushed
do 24000rpm. The Mechatron can do both.

I like Mechatron....but they are so much more expensive. Are they truly worth that much extra? Depending on who you talk to some say yes and some say no. I personally have had an 800W Mechatron and
have used, and abused it for over ten years. Simply brilliant. Actually I have not really abused it, it has had it fair share of crashes but to be honest I treat it as well as I can. It is entirely possible that under the same
circumstances a Chinese spindle would do as well.

If I had the money I would buy a Mechatron. Otherwise, I would buy a GPenny 12000rpm, but use an 800Hz VFD so I could push it out to 24000rpm. The manufacturer does not claim that it can do that sort of service
but I feel sure it could without wrecking itself.

Craig