Re: [CAD_CAM_EDM_DRO] Re: need some gear boxes for twin screws

carlcnc@... wrote:

> Hi Doug
> Guess I better explain more,
> This is a big machine,I will be spinning nuts on 11/2"dia
> screws, Plenty of load/inertia to overcome. I was thinking of using
> the servos I have on hand hand. Seems that trying to run two servos
> from one set of pins is asking for trouble.
> I could go back to the BIG steppers [2300oz in] but will lose
> performance.
> If anyone has a "trick' to keep two servos from playing tug of war
> when run with Geckos I would love to hear it!

In commercial CNC machines, this is called a "tandem axis". It is
generally set up with 2 encoders, 2 servo amps, 2 motors and 2
sets of limit and home switches. The gantry or whatever is rigged
with bearings and links so it will not bind if a little off square. When
you home that axis, each side of the tandem homes separately, but
simultaneously, to the home position. From there, the CNC control
keeps them in sync. Unfortunately, our smaller CNC controls don't
support this feature.

Jon