Re: [CAD_CAM_EDM_DRO] stepper - servo Holding tourque

Owen,
I've been following your scenario with interest, and I may have
missed the type of mill you're converting. I'm wrestling with the same kind
of decision.

Marv Frankel
Los Angeles

----- Original Message -----
From: "Owen Lloyd" <sbw@...>
To: <CAD_CAM_EDM_DRO@yahoogroups.com>
Sent: Saturday, November 09, 2002 10:46 PM
Subject: Re: [CAD_CAM_EDM_DRO] stepper - servo Holding tourque


> Jon,
> my decision to go direct drive was more out of convenience. Since I had to
> make new bearing blocks for my ball screw conversion, I decided to build
it
> so the Nema 34 motor could mount right on the end with a keyed female
> coupler. I was intending on using minimum 400 in/oz steppers, though I am
> likely going to purchase the Motion Group
> [http://www.motiongroup.com/cncpkg.htm%5d package with 750 on/in motors. My
> ball screw is a .200 pitch.
> Thanks for the informative link. I'll be sure to read it through several
> times.
> Owen
>
> > Well, with a direct drive, you get much higher speeds, and less torque.
> > With a 2:1 toothed belt
> > reduction, you double the torque but half the speed. Servo motors
> > usually have lots of speed,
> > so a belt reduction is a good move. Steppers are usually lacking on
> > high speed, so direct
> > drive may be a much better choice.
> >
> > If you give me specifics, (motor specs, lead screw TPI) I can crank some
> > numbers for you.
> > Or, see my page on this at http://www.timgoldstein.com/CAD_CAM/motor.htm
> >
> > Jon
>
>
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