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.

[m_c]

Perhaps microstepping should only be considered to reduce vibration by cloer approaching a sine/cos waveform.

Primarily, the main function of microstepping is to help motors turn smoothly at low speeds.
If you want to read about various aspects of stepper drivers, and have several hours to spare, search out the many posts by Mariss Freimanis over on CNC Zone, particuarily in the Gecko Drive and Stepper Motor forums. Mariss is the brains behind Gecko Drives, so knows quite a bit about them!


Forgot to mention, keep us updated about the build/conversion!
I'm considering a SX2 once funds allow, as it's about the ideal size for some parts I'm thinking about making/selling.