RE: [CAD_CAM_EDM_DRO] FA, Bridgeport NEMA 42 stepper motor

> -----Original Message-----
> Tim,
>
> May I make a suggestion? Some time ago, Dan Mauch made the
> comment that the
> Gecko drives on a 500 line encoder divided by 2 (Gecko 340)
> ran quieter in
> idle because of the higher encoder resolution, (assuming you
> are designing
> around a 250 line encoder. You might consider the 340's over
> the 320's to
> keep your feed rates up there. I don't know if others would
> agree, but
> that's my 2 cents, and maybe others will comment. For the
> little difference
> in price, why not try the 340's?

I already have the 250 line encoders installed in the motors and I already
had the G320's on hand. Lots of trade offs in picking the encoder count and
if using a G340 the multiplication ratio. With a 500 line encoder and a 2X
multiplication you will likely get lower rapids if you are really pushing it
as allowed error is cut in half from a G320 and 250 line encoders. Not
necessarily a concern for many and maybe a problem is someone is actually
cutting at these extreme rates. I would agree that the servos are probably
quieter as they are held in a tighter range when dithering so they likely
can not bounce as fast. I will say that with Bridgett it is not the sound of
the servos you hear when she is running!

> Mariss's next run of G340's will exhibit reduced hunting
> while the motors
> are sitting still, but that design is a couple of months away, as I
> understand it.

Both G320 and G340. It is not that thy will hunt (dither) less, but that it
will be at a rate which makes it non-auditable.

> I hope my 2 cents is worth that much. I get so much help
> from this forum,
> that I want to help in any way I can.
>
> Can you please summarize your experience with microstepping
> the steppers on
> Bridgett and Gecko's? I think you did that at first, didn't you?

I ran the G210a on a 62 VDC power supply driven by DeskWinNC. Performance
was certainly acceptable. Got 90 ipm on the Y and 30 ipm or so (did not
spend time tuning the acceleration) on the Z. X was a bust as the motor
turned out to be partial demagnetized and just will not work for crap with
the micro stepper controller. If I didn't already have 3 G320's and the
stepper motor was not bad I would have likely set it up with the G210a's
while I saved my pennies to move to servos. After having used both steppers
and the G320 step and direction servos I am sold on the servos. This is my
second machine to have tried both steppers and servos on and the servos out
perform the steppers both times and not by just a little. Rapids improve
greatly and there is no sensitivity to pulse variation from the software.

Tim
[Denver, CO]

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