Re: [CAD_CAM_EDM_DRO] Re: Vertex Rotary Table Backlash

----- Original Message -----
From: stevenson_engineers <john@...>
To: <CAD_CAM_EDM_DRO@yahoogroups.com>
Sent: Monday, May 26, 2003 4:19 PM
Subject: [CAD_CAM_EDM_DRO] Re: Vertex Rotary Table Backlash


> >--- In CAD_CAM_EDM_DRO@yahoogroups.com, "alex" <telecomt@t...> wrote:
> > In this case, why not to build rotary table driven by the belt/chain
> > directly from
> > stepper, with no worm gear involved?
> > Alex
>
> Because you need the high worm ratio to prevent cutting forces
> driving the table. Try turning a 10:1 gearbox the wrong way, it's not
> that hard and to get a high enough ratio that would prevent run back
> on chain or belt would be an enormous ratio and physically impossible
> to fit in.

Thank you for the explanation, but for this, brake can be invoked!

> This is one application where the worm and wheel is ideal.
> Backlash if not excessive shouldn't be a problem as you should always
> go one way and the commercial units such as the Vetex are very good
> in this respect. Far better than most of the home made gear we had to
> put up with before the advent of this small affordable equipment.
>
> John S.
Regards, Alex