Stepper resolution

[dfwiii]

Please Help? I am building a machine and am stuck on one issue. I am using custom made nylon nuts and 3/8'' threaded rods. This is my first try at this so i am keeping it simple ... My question is how will the stepper motors know how many times to step or pulse for a given distance? Or how do I set the ratio's up for getting this done? For instance if i want to cut a 2'' square, how will the machine or steppers convert the G-code to translate this info into correct and accurate motion?

Thanks,
Bert Wilson

[jeffs555]

There will be a setting in the software you use to set the distance per step.

[scratch_6057]

Jeff is absolutely correct, but to give a little more detail,
the “motors” KNOW nothing except to step X degrees for each
pulse they receive, depending on how they are physically
made, 0.9 deg 400 SPR, 1.8 deg 200 SPR, 3.6 deg 100 SPR
etc. ½ step, ¼ step, micro-stepping, etc are setup in a
combination of places on the control electronics and software.

If you are looking for a way to determine how far a specific
leadscrew will drive a load for a given number of revolutions
or pulses then consider the following for a system with 1.8 deg
200 step per revolution motors and a direct coupled (or 1:1 belt or gearing)
and a 3/8 x 16 Threads Per Inch allthread.

1 inch divided by 16 (TPI) equals 0.0625 inches.
So for every single rotation of the leadscrew, a nut or load
threaded onto the leadscrew will travel 0.0625 inch.

0.0625 inches divided by 200 (steps) equals 0.0003125 inches
For each PULSE to the motor, the nut or load will travel 0.0003125 inches.

With this setup, if you intended to move the load ½ inch you would have to provide 1600 pulses to the motor

0.5 inches divided by 0.0003125 inches (for each pulse / step at 200 Steps Per Revolution)