DC Servo for Mach3 spindle

[zvizdic]

Hi
I have Kollmorgen U12M4 Servo Disc DC Motor and I am hoping to use as a spindle motor for my milling machine.
I am going to add a Mach encoder to the spindle and drive 2/1 ratio mining running a motor faster then a spindle.
Motor has a torque 1316 oz-in or 9.3 Nm and max rpm at 6000 rpm.
Any suggestion for driver or integration whit Mach3
My plan is to ad encoder to spindle top and use Mach3 Pwm output to driver and encoder to read speed (closed loop).
Integration is most of my concern would I be able to do taping (rigid taping or close to it) forward to reverse do I need some braking for spindle?
I build from scratch machine steel tubing frame, linear rails, ball screws and closed loop steppers 2.2 Nm from scratch spindle using car wheel bearings (modified) .
So happy how it turned out how powerful it is and precise considering (all coming from China ) such small motors.
I guess Mach3 can do M3 and M4 (did not check) Pwm and encoder do good job on a lathe could not find mill videos .

Motor spec link https://www.kollmorgen.com/en-us/pro...sc-catalog-en/

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[joeavaerage]

Hi,
I doubt you'll be able to do rigid tapping even if you do put an encoder on it.

Rigid tapping REQUIRES that the spindle be exactly helically synchronised with the Z axis (a mill) or X axis (a lathe), so the spindle
is in effect a C axis, that is it needs to be position capable.

I have an AC servo which I use as a spindle in my mill, and when I want to do rigid tapping I configure it as a C axis. It works fine, although I don't use it as much
as I thought I would, but do use thread milling much more than I thought I would.

An encoder would allow Mach3 to read the speed, but to my knowledge Mach3 does not change the PWM to effect a closed loop speed control. I use Mach4, and have done
so for seven years, and Mach3 prior to that. Mach4 cannot in itself do closed loop spindle speed control either. My motion controller, an ESS, has some months ago added
closed loop spindle speed control (by varying the PMW duty cycle) on its Mach4 plugin only. It cannot do closed loop with Mach3. It can and does read the speed, and can
use the index signal to correctly 'phase' a single point lathe threading cycle, but not control the speed.

Do you actually need speed control that tight anyway?

Remember all those years we use manual mills and lathes and none of them had closed loop anything! Most of then didn't even have continuously variable spindle speed either,it was all set by gears,
you got as close as you could and carried on. Do you actually need speed control like that?

Craig

[zvizdic]

Thanks for a quick reply!
You are right I don’t really need rigid taping it is more of a learning process.
I do work in the field and use cnc professional mill and lathe .
And often skip taping on cnc mill unless many parts are needed (manual drill press is just as quick).
Since Mach3 support G84 I assumed it would .
Now that I think little deeper that is why Mach3 has set rpm and actual rpm.
Probably just divide set max rpm in spindle setting to percentage of pulses on time so loosing torque as a result.
If that is the case only way would be closing the loop to Dc servo driver and matching rpm as close as possible to Mach3 and use spring loaded taping holder.

[mactec54]

Hi
I have Kollmorgen U12M4 Servo Disc DC Motor and I am hoping to use as a spindle motor for my milling machine.
I am going to add a Mach encoder to the spindle and drive 2/1 ratio mining running a motor faster then a spindle.
Motor has a torque 1316 oz-in or 9.3 Nm and max rpm at 6000 rpm.
Any suggestion for driver or integration whit Mach3
My plan is to ad encoder to spindle top and use Mach3 Pwm output to driver and encoder to read speed (closed loop).
Integration is most of my concern would I be able to do taping (rigid taping or close to it) forward to reverse do I need some braking for spindle?
I build from scratch machine steel tubing frame, linear rails, ball screws and closed loop steppers 2.2 Nm from scratch spindle using car wheel bearings (modified) .
So happy how it turned out how powerful it is and precise considering (all coming from China ) such small motors.
I guess Mach3 can do M3 and M4 (did not check) Pwm and encoder do good job on a lathe could not find mill videos .

Motor spec link https://www.kollmorgen.com/en-us/pro...sc-catalog-en/

If you want to have spindle control, then you would be best you use Acorn cnc control, which can control the spindle speeds with an encoder (closed loop control) and do rigid tapping.

[samco]

Or linuxcnc. There are very few controls that do rigid tapping..

Mach4 with the right motion control hardware?
Acorn
Linuxcnc

sam

[Al_The_Man]

There is also DynoMotion as a true closed loop CNC system.
Reasonably priced contender also.
See forum here.

[zvizdic]

Thanks all for replying !
As I stated it is a learning process primly. I have Low budget Mach3 machine no planed upgrades other then to learn integration like this.
So far what I learned is Mach3 sends simple Pwm pulse +-0- 5 v I would need to use PID motor driver to get close to true rpm (by lot of fiddling around) no god for rigid taping.
But good enough to fly cut at low rpm and high torque. To me is important to haw this high torque at all speeds.
So I am going to try to learn Arduino uno with Pid control and dc driver then lop encoder to Arduino possibly match rpm as close as possible to Mach3.All components on hand.

[dazp1976]

You mention the motor but what driver are you going to be using?.
Looking at the power output of motor (rated watts-284) I'm not convinced it's good for a spindle. More of an axis unit.

[joeavaerage]

Hi,

Looking at the power output of motor (rated watts-284) I'm not convinced it's good for a spindle. More of an axis unit.

Where di your 284W come from.?

9.3Nm, 6000 rpm
Power = 9.3 x (6000/60) x 2PI
=5843 W
5.8kW which should make quite a respectable spindle.

[zvizdic]

Hi
Just to clear some things out. Torque on this motor is higher then my single phase ac motor currently on the machine (7.2A at 115V and 3450rpm I am cutting speed to half by pulleys ).
At current setup I have enough power to do cutting of a steel but larger tools like 3/4 end mill is getting stopped at slower feeds.
This servo disc is going to be driven with same pulleys 2/1 so slower hence more torque.

[zvizdic]

I have to mention that I have to stay at low power consumption (in the shed on a single plug at 120V).
Just to give you the idea how much power is drown when I run the machine on current setup (450W all tougher laptop,machine with ac motor running a spindle).
I can easily swap spindle with router for wood machining and all power consumption is 250W average.
To answer Daz question I mentioned Arduino and dc motor driver.

[dazp1976]

Hi
Where di your 284W come from.?
9.3Nm, 6000 rpm
Power = 9.3 x (6000/60) x 2PI
=5843 W
5.8kW which should make quite a respectable spindle.

Says it in the bloody spec page on P16
https://www.kollmorgen.com/en-us/pro...sc-catalog-en/

The fact it's only 53mm long says enough.
rated:
Cont 3000rpm (max6k)
watts= 284
vdc= 43.4
Stall currerent cont= 8.1A
Weight= 3.6kg.


It's all in there.

My servo is 1.8kw and is 3 times as long and almost 3 times as heavy!!!?.

[zvizdic]

Says it in the bloody spec page on P16
https://www.kollmorgen.com/en-us/pro...sc-catalog-en/

The fact it's only 53mm long says enough.
rated:
Cont 3000rpm (max6k)
watts= 284
vdc= 43.4
Stall currerent cont= 8.1A
Weight= 3.6kg.


It's all in there.

My servo is 1.8kw and is 3 times as long and almost 3 times as heavy!!!?.

What is your motor torque in Nm ?
If am correct brushless ac is a bigger in size but less torque then brush dc servo motor.

[mactec54]

Hi,



Where di your 284W come from.?

9.3Nm, 6000 rpm
Power = 9.3 x (6000/60) x 2PI
=5843 W
5.8kW which should make quite a respectable spindle.

You are playing with meaningless numbers again, the motor specs are nothing like that,

The motor is 284watts with a stall torque of 122 oz-in the 2:1 gearing will help, not an ideal spindle motor though

[zvizdic]

You are playing with meaningless numbers again, the motor specs are nothing like that,

The motor is 284watts with a stall torque of 122 oz-in the 2:1 gearing will help, not an ideal spindle motor though

You are right not ideal motor but is one that I have on hand .
It’s in my opinion better then jacuzzi motor used know (also on hand)
And I can easily switch between them if needed.

[zvizdic]

Here is the video running on current setup in my shed.

[mactec54]

You are right not ideal motor but is one that I have on hand .
It’s in my opinion better then jacuzzi motor used know (also on hand)
And I can easily switch between them if needed.

I agree, you use what you have and adjust feeds and speeds to suit the power you have, I have done the same many times.

[joeavaerage]

Hi,
well apologies, I got those numbers from OPs first post, he said 9Nm at 6000rpm.

Craig

[zvizdic]

Exactly it is hobby machine/ learning process into electronic associated with it.
If it starts making money then yes investing in better hardware will be ok.
I like challenge of learning new things and coming up with simple and cheap solutions.
As you can see in the video I build my own spindle Cat/bt with spring holding pull stud that in the future I can add air or some other tool release.

[dazp1976]

What is your motor torque in Nm ?
If am correct brushless ac is a bigger in size but less torque then brush dc servo motor.

6nm or (600n-cm) constant. Peak of 18nm or (1800n-cm).
Or 850 / 2550 oz-in.
Voltage rated 220.