Hardinge Lathe CNC Retrofit/Conversion

[Muzzer]

If you don't plan to use ethercat, it looks to me as if the Acornsix would do the closed loop control of both the axes and the spindle. It's less expensive than the Hickory and that also applies to the associated software.upgrades.

If you prefer to use the motor encoders for axis position feedback, rather than use linear encoders, you can usually take an "encoder output" from the servo driver back to the system controller. This encoder signal can be a different resolution to the actual motor encoder itself - you can set the resolution in the driver setup

Most spindle VFDs are intended for speed control, rather than position control (which would be a servo's job) and they tend to be sensorless. This means you need to provide your own position encoder unless you have a fairly exotic VFD with position sensing. Furthermore, for cnc control, the spindle encoder needs to be directly geared to the spindle 1:1, which isn't usually the case if the encoder is mounted in spindle motor - unless the motor is part of the spindle itself.