How do you drive your gantry cnc

[nash]

1. Central drive with a fixed table and a fully closed gantry section (like a rectangle) , with screw and nut.
2. One drive on the side with screw and nut with a fully closed gantry.
3. One drive on the side with screw and nut with open gantry (like a C rotated clockwise by 90deg).
4. One drive with timing belt for two screws and nuts on each side of an open gantry.
5. Two drives (one on each side) with screws and nuts on each side of an open gantry.
6. Two drives with rack and pinion on each side of an open gantry.

[Jason Marsha]

Two drives with belts on each side of an open gantry.

Jason

[nash]

Jason, thanks for the input. Too late to add that item. Donno if this poll is editable. Additionally, I was trying to understand gantry drives, with screw/nuts... sorry for missing the option of belts, chains, and rack/pinion. Maybe we should run another poll for linear motion drivers (screw/nut, belts, chains, and rack/pinion).

N

[Halfnutz]

I have one built with a single ball-screw under the table, and I'm working on another that will have a belt on each side with seperate servo's and drivers.

[nash]

Halfnutz, there are certainly many more combinations than we can list in a simple poll. Whats the accuracy that you want to drive out of your machine with the belts+servos?

[Halfnutz]

Originally Posted by nash Halfnutz, there are certainly many more combinations than we can list in a simple poll. Whats the accuracy that you want to drive out of your machine with the belts+servos?

Since this will be used for plasma or Oxy-Fuel, I am not too concerned about the accuracy, although the Y axis and Z axis which are allready built have .0005 in. repeatability and resolution. I am unsure of the accuracy, I havent done any measurements that small. I know it is more accurate than I need though. With these 3000RPM AC servo motors I know I need to have the smallest possible drive pulley I can get on the motor shaft, from some crude calculations I did. I am going to try it without gear reduction, although a 2:1 reduction would be best. If it turns out to be too fast I will gear it down later.