Re: [CAD_CAM_EDM_DRO] Is this a silly idea

Chris Cain wrote:

>I am thinking of building a small CNC mill and looking at X-Y tables
>construction is difficult and good ones are expensive.
>One though I had was that rather than have an X-Y table as the base of
>the mill what about a X - theta table.
>i.e. a rotary table on a cross slide, no Y movement at all.
>
>As far as I can see this would be a lot simpler to make as small rotary
>tables can be purchased relatively cheaply.
>With CNC control it should be possible to duplicate any cutting move
>that could be done on an X-Y table as well
>As a number that would be difficult to do on a straight X-Y table.
>
>About the only down side I can see is that I would probably have to
>write the software myself to control it ?
>
>

No, you should be able to write a simple kinematics routine for
EMC, and use the rest as is. The only thing you have to worry
about is the "gimbal lock" problem. If you ever drive the machine
through the 0 - 0 point, the results are unpredictable at the center
of rotation of the rotary axis.

Jon