cnc lathe with C axis

[whatisor]

Do you think if there are differences between nomal cnc lath's spindle motor and C-axis cnc lathe's spindle motor?
If there are, what is the diffrences?
I plan to use servo motor( which is often used for X,Y,X) instead of spindle motor.What do you thick about it?

[Al_The_Man]

If you use a Servo motor of sufficient size, it should be possible to achieve C axis control, on large machines, the lathe C axis was often performed by a separate C axis motor, that was disabled when the main spindle motor ran, this was to avoid the more expensive servo system on a large motor.
I am using a Converted Fanuc AC servo motor for a small lathe C axis application.
Al.

[whatisor]

ok,thank you for your exprimence.
So do you think what is better for C axis control between servo motor series and spindle motor series if I suppose their power(or Torque) is same?

[Al_The_Man]

In a DIY situation I would prefer using a Servo motor, you get the advantage of encoder feedback to the controller, the only thing is if the motor is through gearing to the spindle, you may have to put a Z pulse detector off the final shaft for homing the C axis, or use an encoder on the final spindle if the motor to spindle coupling has backlash or gear box.
Al.

[whatisor]

Nowaday, maybe there are not very much differences between Spindle motor series and Servo motor series. I think so because I have see this Spindle motor series
Fanuc AC spindle motor alpha series
or Fanuc AC spindle motor beta series
Fanuc introduces indetail C axis contour function like a optional funtion.
Of course, we need a feedback encoder. But more specially, this spindle motor series has built-in coder
You can review them in this:
http://www.docstoc.com/docs/28705103...-Descriptions/

So, I if you reviewed this, do you think built-in encoder(feedback directly from motor axis because built-in coder inside motor) is impossible to solve Belt or gear blackflash?

[arzoo105]

Hi

can anybody tell me can ac induction motor be use as C-axis , as i have to make groove , pockets and slots by using C-axis.

regards
arsalan