Servo Drive with Magnetic Scale Feedback

[Toyhacker]

Hello all,
About a year ago I sent the worn leadscrews on my Prolight 2000 out to be rebuilt as they had considerable backlash. This cured the backlash, but the x-screw is worn unevenly so that it can be .005 out in an inch. Rather than buy a new lead screw, I'm thinking of adding a magnetic scale to the x-axis and converting the output to mimic the 8 bit grey code of the shaft encoder on the servo shaft. Does anyone know of a reason that this wouldn't work?

Regards

[PBr]

I think there are 2 things to be aware of:
1 - resolution/accurracy of the machine willl be the same as the scale - and the servos work with some +- counts around the setpoint position.
2 - any backlash which may come in in motor-screw-feedback system may result in unstable servo loop which is very hard to eliminate AFAIK.