RE: [CAD_CAM_EDM_DRO] Gecko G340 Smoothness

First off while the G3X0 drives are servos because they are driven from
the computer in distinct increments (steps) the motion at very low feed
rates will look just like a stepper (meaning that if you signal a 1 step
move it will get there as fast as it can with no interpretation for
velocity). With that said if you decrease the distance moved in a single
step you can then get smoother motion by calling 5 small steps timed at
even intravals than by calling for 1 step that moves 5 times as far.

This is simplifying it some as Mariss had made the drive to spread the
generated steps over a certain window and once you get over some unknown
speed the steps will blur together and you will also likely be driving
with a continual error signal so the motor will not stop, start, stop,
start like it will at very slow feeds.

Tim
[Denver, CO]

> -----Original Message-----
>
>
> Have my mill moving again with the Gecko drives and as usual have a
> question.
>
> I have some motor noise at low speeds (5 ipm), more than at the
> rapids I am getting. (80 ipm) I can see the table screws pause as
> they turn (very short stop starts) so I may have some acme screw -
> bronze nut stop/start friction. I looks like a stepper motion.
>
> More info:
> The drives are in the 5x setting and about 4000 steps/in so the
> encoders are putting out about 20000 steps/inch.
>
> Any one (Tim? Mariss?) have an opinion on whether changing to the 1x
> mode would make the motion smoother, assuming I can coerce EMC into
> pushing out the steps fast enough?
>
> P.S. The burn table conversion ( EMC and Dan Mauch's G340 servo box )
> I have previously posted about is working well!
>
> Andy Olney
> andy@...
> Grizzly G1004 small knee mill conversion
>
>
>
>
> Addresses:
> FAQ: http://www.ktmarketing.com/faq.html
> FILES: http://groups.yahoo.com/group/CAD_CAM_EDM_DRO/files/