Re: Opinions on .9 degree steppers

Hello,

The smallest step size I've seen "normally" is .45°/step

Since the rotation angle is smaller, there "should" be
less "ringing", (all else being equal), when compared to a 1.8°
motor. This might allow the .9 motor to accelerate more quickly than
the 1.8°.

However, some considerations for a sherline. The typical sherline
setup is direct drive to 20tpi leadscrews, and driven half or full
step; which gives 4K or 8k steps per inch. This is far greater
precision than the machine itself is capable of. These motors will
need 8K or 16K per inch! I'd call this "empty" resolution... But you
could run them in full step mode and probably get a little better
performance than 1/2 steping 1.8's. If your controller can handle
the step rate necessary to use them at 16K/inch, they will do nicely,
as you are now getting "quad-stepping" performance, at the 1/2 step
price.

(side note to Mariss) Is this correct? I've often wondered how
the "smaller" degree motors used halfstep compared to a setup using
microstepping. If the two systems are equivalent accel/decel wise, it
would seem prudent to use as small a "manufactured" angle as
possible, and use cheap 1/2 step drives, since presumably the
positional ACCURACY of the mechanical step is better? than the
accuracy of a microstep... (assuming NON- matched motor/drives)

HTH and TIA,

Ballendo

> datac@l... wrote:
> > I just picked up (6)Brand new, 2 phase, Vexta Nema 23, 118 oz, .9
> > degree steppers (400 steps per rev - #PH268M-E1.5). They seem like
> > some nice motors. Anyone have any comments about their use

compared to

> > the 1.8's ?
> >
> > I am assuming they will be very smooth running compared to
> > 1.8's..... Probably even quieter.
> >
> > I can't say I ever came across .9's in the surplus market, usually
> > they are coarser step units. Does any one know if there are finer

step

> > motors than .9 out there?