Help choosing acme rod

[Spiral_72]

I’d like a little advice choosing an acme rod. I plan to use a delrin or similar nut.

I use these steppers: 103H7126-0110 - 1A, 1.27Nm (179.8oz/in) holding torque

I measured the top speed of the stepper, before it started chattering, at 135rpm. The stepper is installed on my current CNC, so it was under a minor load driving the screw.

I’d like to design a new CNC capable of 200 inches per minute. A little calculating gives me 1.47 inches per revolution. Is this reasonable? Is ½” acme rod a good choice at 130 rpm or should I go bigger? What pitch? Single start? Multi-start?

I can do the single start math, but I don’t understand the multi-start stuff.

Also, 130rpm seems awful slow. Should I suspect a problem with my stepper driver? Or is this reasonable?

[ger21]

The right motor - drive - power supply combination should get you around 1000 rpm. You probably don't want to try to achieve your goal speed at 135 rpm.

[Spiral_72]

Can you get 1000rpm out of a stepper!?

Based on that, either I've got the wrong steppers, or I'm driving them wrong?

[Spiral_72]

I attached the torque curve for my stepper. It registers 1000rpm but it looks like it develops very little torque at that speed.

I suppose this is a bad thing for my plans eh?

[ger21]

Originally Posted by Spiral_72 Can you get 1000rpm out of a stepper!? Based on that, either I've got the wrong steppers, or I'm driving them wrong?

You'll need a higher current motor with low inductance. Gecko says they're G540 can get 1200-1300 rpm put of similarly sized motors, but they must have low inductance. Power supply voltage plays a large part in top speed, as well.

You didn't say what drives you're using, but I think most people here are getting 500-800 rpm out of their motors.

[ger21]

This Vexta still has 30% of it's torque at 2000 rpm, as an example. It's a 6A motor with very low inductance, and the torque curve is running it at 60V.