Re: X-Y Table, Rotary Table for CNC INFO

Ray,

Good point.
But it would be repeatable, and therefore possible to correct in
software. Possibly even with EMC's leadscrew correction, though the
error is "squished at one end" of the travel.

Ballendo

--- In CAD_CAM_EDM_DRO@yahoogroups.com, Ray Henry <rehenry@u...>
wrote:

>
> >    From: "ballendo <ballendo@y...>" <ballendo@y...>
> > Subject: Re: X-Y Table, Rotary Table for CNC INFO
> <s>
> > Think scissor lift table. A couple of accurately placed pivots;

ONE

> > screw, lots of force. Problem: Stability in the direction perp. to
> > the scissor. Fix that with a vertical guidepost (or two. Note that
> > these DON'T need to be heavy duty linear motion component quality;
> > they are just keeping the structure stable in one axis(resisting

only

> > side loads).
>
> With a scissor you will need to be a bit careful where you place

the

> screw. The usual place is in the middle between pivot arms and
> perpendicular to the motion. Many car jacks are made this way.

With

> something like this, z motion would NOT be linearly related to

rotation

> of the screw.
>
> Ray