[harryn]

Hi, I am looking into the possibility of using a VMC to do some high speed, finely spaced assembly work.

The main difference between what a VMC does and what this project needs is that the spindle drive would need to be replaced by a motor that can fairly accurately position the rotation (like a servo or stepper does) plus of course the control software.

While a VMC is in some ways over kill, it is also a known, off the shelf entity and easy to replicate. The movement speeds are also quite fast and accurate.

As an example of what is needed, consider the speed and movement of a Haas DM2, and then replace the spindle drive with a servo motor with similar capability as the other axis drives. It doesn't have to be Haas, that is just an example.

Has anyone found a VMC that has a servo already, or retrofitted a positioning servo into a VMC or similar?

Thanks

Harry

[charlieslasher]

Servo will give good positioning and low speed torque. An induction motor can be positioned with a closed loop vector vfd. Depends on what you need to do.

[louieatienza]

Hi, I am looking into the possibility of using a VMC to do some high speed, finely spaced assembly work.

The main difference between what a VMC does and what this project needs is that the spindle drive would need to be replaced by a motor that can fairly accurately position the rotation (like a servo or stepper does) plus of course the control software.

While a VMC is in some ways over kill, it is also a known, off the shelf entity and easy to replicate. The movement speeds are also quite fast and accurate.

As an example of what is needed, consider the speed and movement of a Haas DM2, and then replace the spindle drive with a servo motor with similar capability as the other axis drives. It doesn't have to be Haas, that is just an example.

Has anyone found a VMC that has a servo already, or retrofitted a positioning servo into a VMC or similar?

Thanks

Harry

There are many VMCs that can "clock" their spindle, for example for aggregate heads or larger tooling, as well as rigid tapping.

[hanermo]

Lots do already, but ... they are high end machines, mostly.
So, its 200k and up..

Since the controls are closed, You wont be able to just swap a VFD for a servo, unless its a manufacturer offered option.
And maybe You can, if the control is the same, +/- analogue or even step/dir.

But the totally different tuning parameters may not be "allowed" on the control as in out-of-range.
I think its technically perfectly doable, and would be easy, if the manufacturer supports you.

I use a servo spindle on my lathes C axis with positioning.
And will put a servo spindle on the mill.
Nothing to it, on an open control.

I use industrial ac servos, with step/dir.

[vegipete]

Do you need controlled rotation of the spindle or just rotate to and stop at a particular angle.

If the VMC has a tool changer then it can orient the spindle. At least some machines allow G-Code to set the angle of the spindle origin. By adjusting this origin angle, the spindle can be rotated and stopped at any desired angle, within the precision of the spindle encoder. Just don't forget to set the origin angle back to the correct value afterwards.

[SwampDonkey]

Do you need controlled rotation of the spindle or just rotate to and stop at a particular angle.

If the VMC has a tool changer then it can orient the spindle. At least some machines allow G-Code to set the angle of the spindle origin. By adjusting this origin angle, the spindle can be rotated and stopped at any desired angle, within the precision of the spindle encoder. Just don't forget to set the origin angle back to the correct value afterwards.

How big of a servo do you need? I have some large high-torque DC servos that would be ideal for a servo spindle conversion.