Re: [CAD_CAM_EDM_DRO] run two geckos from same pins

Doug Fortune wrote:

>
> Back to your XXYZ cnc router, it would be great to
> to run a timing belt across both X axes (even though
> you have 2 motors with 1 or 2 controllers), just to
> keep them both honest (because steppers are <usually>
> open loop systems).
>

I want to elaborate on the above comment: normally if
a stepper system looses a step (or multiple steps), then
your position is off - thus wrecking the part. This is
unfortunate, but not a disaster.

But in an XXYZ gantry, if the two X axes are not moving
in unison (because of lost steps), there is enough power
(through the screws leverage) to pull the gantry itself
apart - thus wrecking your machine - a disaster indeed!

Thats why I like tying two X axes together with a timing
belt even though there are two X axes motors. As for
servos, theoretically the two motors can't differ by more
than a few steps if everything is working properly. If
they do get too far apart, the system should stop with a
a following error fault. But it is nice insurance anyway
to have the two axes tied together.

Doug Fortune
http://www.cncKITS.com