Re: gEDA-user: Universal Turin^H^H^H^H^Hmilling machine

[Karel Kulhavy <clock@twibright.com>]

On Sun, Nov 07, 2004 at 08:57:18AM -0500, Bob Paddock wrote:
> 
> > > http://freeandeasy.sourceforge.net/
> > >
> > > The "FreeAndEasy" project is interesting in that it is a round/rotating
> > > version, not X/Y, using polar co-ordinates.  Working with rotating discs
> > > removes all problems associated with backlash in linear slides.
> >
> > I saw a XY table in the videos and on the pag they also write it's an XY
> > machine.
> 
> Yes they discuss the problems with the X/Y approach which lead to the polar 
> machine.  Look at the other links:
> 
> http://freeandeasy.sourceforge.net/rotsim.php
> http://freeandeasy.sourceforge.net/rotary.php
> http://freeandeasy.sourceforge.net/rotproto.php
> http://freeandeasy.sourceforge.net/zaxis.php

I think the motors and belts could be thrown out, the turntable wheels made
from thick copper and induction coils added so that an asynchronous motor
would be formed.

You could pump nearly any desired current into them provided they wouldn't
overheat (and water cooling is trivial too ;-) ). This way you might get brutal
acceleration for a NTN cost :) The motors and belts will slip.

Then the mechanics shit would be completely away. Driving a bunch of coils
and high currents is not a problem for electronics. We all know how to
design it :)

For examples roller coasters are being accelerated an braked this way.

And a Gray-code readout strip (graycode is simple - take a normal binary code
and derivate it from left), use it in feedback loop and you get unprecedented
performance - or not? :)

The ball bearings are OK. They are cheap and very tight precision by
default. I have redesigne a bike alternator using double ball bearing
and it runs just fine, even when buried under mud :)

> 
> Move the blue dots to see how it works, simulation is very cool.

The 3rd axis doesn't work for me, but I determined it partially from
the pictures.
> 
Cl<