Thread: New power for mini mill???

Hi All,
I'm wondering if anyone on here could suggest a motor and inverter combination, to replace the POC electrics on my mini mill. Have read an article somewhere that someone used a .37 KW inverter and a 3 phase Teco dual voltage 4 pole motor with a flange mount to run an X3 mini mill, I realise that this is probably too large for the X2, wondering if anything similar, could be done for it. I've spent enough on repairs to have bought another one +. Time to set it up, as a decent robust electronic machine.
Thanks
Kryn

Kryn,

You may need a 3 phase motor of about 0.55kW to give enough power at low speeds, and this could weigh more than 15 -20 kg, which could double the existing head weight.
You would need to replace the support spring mechanism with an air spring to support this extra weight.
The motor would also need to be mounted as centrally as possible to reduce side loads on the dovetail.
I haven't any advice on a suitable VSD.

Sounds like a good project (You can tell us what doesn't work so well so i can avoid these problems when I do it!).

Andrew.

The specs say this mill uses 3/4HP (0.55kW) motor?

If that is the case then a .37kW inverter would seem too light.

If you want torque at the low speed end then you will ned to double the power requirements.
I'd say you need a 1.5HP motor but if weight is a problem then maybe a 1HP would do.

If you used an Aluminium body motor you should be able to get one that weights around 10kg - maybe even that is too much.

If you can't increase the head weight then maybe a Vector drive VFD will suffice since it provides more torque at low revs than the non-vector drives

Originally Posted by KBs PensNmore

Hi All,
I'm wondering if anyone on here could suggest a motor and inverter combination, to replace the POC electrics on my mini mill. Have read an article somewhere that someone used a .37 KW inverter and a 3 phase Teco dual voltage 4 pole motor with a flange mount to run an X3 mini mill, I realise that this is probably too large for the X2, wondering if anything similar, could be done for it. I've spent enough on repairs to have bought another one +. Time to set it up, as a decent robust electronic machine.
Thanks
Kryn

That two part article was from me. Ask if you need to know more detail.
1/2 hp vector VFD is in my opinion plenty of power for the weight and rigidity of an X3.
I used a 3-speed Polybelt changegear. Whereas the original X3 motor was a 600W DC PM with only a 2-speed gearbox.

The way I did it is probably a bit heavy and overkill for an X2 (remember the X2 net weight is only 50kg, the X3 net weight is 165kg).

Thanks CBA, nice set up you did on that. You were lucky to find a small motor like that, every thing I look at has a shaft on it minimum of 16 mm. Will still keep looking, once I get all the bit I'll contact you for some details etc.
Regards
Kryn

Originally Posted by cba_melbourne

That two part article was from me. Ask if you need to know more detail.
1/2 hp vector VFD is in my opinion plenty of power for the weight and rigidity of an X3.
I used a 3-speed Polybelt changegear. Whereas the original X3 motor was a 600W DC PM with only a 2-speed gearbox.

The way I did it is probably a bit heavy and overkill for an X2 (remember the X2 net weight is only 50kg, the X3 net weight is 165kg).

Is there a link to the article, cheers Shane.

Originally Posted by Auskart

Is there a link to the article, cheers Shane.

http://www.homemodelenginemachinist....1_version2.pdf
http://www.homemodelenginemachinist....2_version2.pdf

Originally Posted by cba_melbourne

http://www.homemodelenginemachinist....1_version2.pdf
http://www.homemodelenginemachinist....2_version2.pdf

Thanks.

Originally Posted by cba_melbourne

That two part article was from me.

Just for the record, your primary lathe is a 165 kg Seig X3?

Originally Posted by cba_melbourne

The whole idea was to have three overlapping speed settings, with at least 1/4HP beingavailable at any speed.

Were you able to transmit the full 1/4 horsepower available through that rubber band?

Originally Posted by Machtool

Just for the record, your primary lathe is a 165 kg Seig X3?

The Sieg X3 is a mill. Yes, its my primary mill.

Originally Posted by Pete F

Were you able to transmit the full 1/4 horsepower available through that rubber band?

Its not rubber. It is a Gates Polyflex 5M Micro-V belt made of endlsess (not spliced) reinforced Polyurethane. Resistant to solvents etc, exactly the same that is probably used in your car and referred to as a serpentine belt. Only the latter are multiple strands to increase power transmission, whereas I use a single strand V belt designed for spindle drives. I choose it, because it is the same as used in my Emco lathe to drive the spindle, so I only need to stock one belt for both machines. Regarding the power rating, it depends on smallest pulley diameter, belt length, and how long it is expected to last. A single strand 5M690 is rated at 0.48HP for intermittant industrial use 5 hours daily for a total of 10,000 hours. I am still on the first belt on the mill after 6 years. On the lathe one belt lasts me about 10 years. The big advantages of using these small lightweight belts is that they do not transmit motor vibrations to the spindle, they do not waste as power with friction, they are endless with no (thumping) splice like rubber V belts, and they do not perish with light/Ozone/solvents like rubber V-belts do. The disadvantage is that they are unforgiving to misalignment. Here a link to the Gates design manual, see page 80ff:
http://www.gates.com/~/media/files/g...ion-manual.pdf

Looking through Google, I found where someone in the USA had used a Treadmill motor and control assembly. Anyone have an idea as to what weight and physical size they would be. Anyone have an assembly they'd like sell??

Kryn, Treadmills are a possibility and quite often found at clean ups or free in the classified adds. I have one for a lathe project which has a 1HP rating 240V DC permanent magnet. Keep in mind though that this size motor is quite large for the X2

What about using one of the 3PH spindles and Hyuanyang VFDs. The 1.5KW version is about the correct size for the X2 and come in ER11 or ER16 versions, 0.8Kw is ideal if you can get one. I recently fitted an air-cooled one to my CNC X2. I can replace the original head when needed. I got an 80mm body spindle with matching clamping bracket, fabricated a base plate to bolt onto the X2 Z-axis casting and fixed the spindle clamp to it.

You could also adapt one of these spindle motors to the existing X2 spindle drive if you want to retain the MT or R8 taper tooling. You might want to look at doing a belt drive conversion while you're at it if still using the plastic gears.

Originally Posted by Swarfmaker1

Kryn, Treadmills are a possibility and quite often found at clean ups or free in the classified adds. I have one for a lathe project which has a 1HP rating 240V DC permanent magnet. Keep in mind though that this size motor is quite large for the X2

What about using one of the 3PH spindles and Hyuanyang VFDs. The 1.5KW version is about the correct size for the X2 and come in ER11 or ER16 versions, 0.8Kw is ideal if you can get one. I recently fitted an air-cooled one to my CNC X2. I can replace the original head when needed. I got an 80mm body spindle with matching clamping bracket, fabricated a base plate to bolt onto the X2 Z-axis casting and fixed the spindle clamp to it.

You could also adapt one of these spindle motors to the existing X2 spindle drive if you want to retain the MT or R8 taper tooling. You might want to look at doing a belt drive conversion while you're at it if still using the plastic gears.

Thanks for the reply Swarfmaker, any chance of some picks or a link to your set up, please, as it sounds very interesting. What was the overall cost, approximately?
If I can keep it going long enough, it was my intention to do a 3 speed belt drive, after about 6 sets of plastic, I installed a set of metal gears, even chewed them up, and I only take light cuts 0.25 mm DOC and very slow on the X/Y 6 turns per minute.
Regards
Kryn