Re: [CAD_CAM_EDM_DRO] Re: Stepper motor speeds

Dave,
Thanks for the information, and the reference to Mariss's message. I
can understand most of it, but his reference to "push" has me a little
confused. The formula for "push" is clear enough, but how do you figure out
how many inches/minute or pounds are required? Don't both factors vary with
the material being milled? If that's the case, it would be helpful if
someone posted a chart with the speed & lbs. for various materials. It might
help me to make an intelligent decision.

Marv Frankel
Los Angeles

----- Original Message -----
From: "turbulatordude" <davemucha@...>
To: <CAD_CAM_EDM_DRO@yahoogroups.com>
Sent: Sunday, November 03, 2002 8:26 AM
Subject: [CAD_CAM_EDM_DRO] Re: Stepper motor speeds


> Hi MArv,
>
> check post 45509. I think that covers it pretty well.
>
> The small section that may be direct is :
>
> quote :
> (2) Steppers have lots of torque at low speeds and very little torque
> at high speeds. This is a good thing. Work is done at low speeds
> where you need a lot of torque; high speeds are usually "rapids"
> where little torque is needed.
>
> As a rule of thumb, steppers are pretty much out of torque (rapids)
> at:
>
> Size 42, 300 to 600 RPM, 800 in-oz or more low-speed torque.
> Size 34, 600 to 1,200 RPM, 150 to 450 in-oz low-speed torque.
> Size 23, 1,200 to 2,400 RPM, 50 to 150 in-oz low-speed torque.
> Size 17, 2,400 to 4,800 RPM, less than 50 in-oz torque.
> end quote
>
> There is more on gearing and stuff.
>
>
>
> Dave
>
>
> --- In CAD_CAM_EDM_DRO@y..., "Marv Frankel" <dcdziner@p...> wrote:
> > Guys,
> > I have a pretty good handle on sizing stepper motors with
> respect
> > to required torque, but I haven't heard any discussions about speed
> > ranges and how they're controlled. I'm in the preliminary stages of
> > designing a CNC retrofit for my Enco full size mill, and would like
> > to use the smallest motor possible, to motorize the fine feed on
> the
> > quill. My down feed requires almost no torque, but retracting
> > requires about 120 to 150 oz/ins. I have enough room to gear the
> > motor to feed at 1:1, 2:1, or 3:1, but I don't know the RPM range I
> > can expect from the motor. Help please!!
> >
> > Marv Frankel
> > Los Angeles
>
>
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