Re: Smaller machine stepper motor speeds and resolution

--- In CAD_CAM_EDM_DRO@y..., Mark Taft <mark.taft@m...> wrote:

> HI everyone,
>
> I am converting a small mill to CNC and have been considering
>stepper motor
> speed and resolution of the z feed.
>
> Its obviously a compromise using steppers, so you need to gear the
>feed at a
> rate which is practical ( fast as possible) while not loosing
>accuracy
> resolution or losing steps ( being under powered).
>
> I have studied the stepper motor specs for the smaller 34 and 23
>sized
> motors.
> They seem to get most torque at about 900 - 1000 Hz..
>
> With a 200 step motor this works out at about 4-5 Rps (revs per
>second) ,
>
> using a lead screw of 60 tpi and a 4 inch travel ( maximum) it
>takes about
> 60 seconds.
>
> I am picking a 60 tpi screw for increased torque.
>

Don't bother.
You are wasting your time with a screw this fine. A micrometer is 40
tpi. Imagine driving that up and down all day with a motor and
expecting it to last and be accurate.
If you are worried about torque just pick the next size up motor.

John S.