Ballscrews v. acme screws

[russell]

1. Backlash nearly always comes down to price. Only you can decide if you want to spend the extra time and money to reduce it.

Agreed

2. Are you basing your calculations on the effiency corrected torque?

I'm basing it on the torque required to transmit a given force to the table for the linear motion taking account of the efficiency of the screws.

2/3. Plus I've seen it mentioned that you shouldn't rely on microstepping for positioning and you should only expect accuracy to the nearest full step.

Good point and another argument against direct driving a ballscrew. Perhaps microstepping should only be considered to reduce vibration by cloer approaching a sine/cos waveform.

If you're unsure, then go cnc with the standard acme screws, and see how you get on. You can always convert to ball screws at a later date.