Re: new

[Ray Henry <rehenry-at-up.net>]

AJ

Hi and welcome to the EMC users list.  Yes a servo system can easily be 
positioned to 0.1 mm.  You will want to use encoders that are a bit more 
accurate than that.  Some suggest at least four times the accuracy that you 
wish to achieve.  The EMC software would have no major problem with that 
level of accuracy.  The biggest problem that you will face is how to drive 
the axes and mount an encoder.

Will you need a line follower like you have with the existing table or can 
your shapes all be done with cad or hand written g-code?  I have the rough 
makings of a shape selection script for EMC.  It works a bit like the Linde 
systems that are popular around here.  Select a shape, enter dimensions, 
orient, repeat and it creates the g-code to produce the parts.  Burn 
through can be handled with a dwell.  

There is a user that built one of these tables that needed instant on for 
his cutting device.  The EMC code was hacked to provide this signal through 
the parallel port.  If you do not need instant on, you can easily use the 
spindle on signal or one of the coolant signals.

Hope this helps

Ray   


On Sunday 14 April 2002 10:30 am, you wrote:
> hello,
>
> I have a question on building a cnc-controlled flame/plasma based cutting
> machine. We have a machine with plasma and flame torches which is driven
> by servo-motors. It also has an eye with which it can follow a black
> linedrawing on white paper. My dad knows a lot about electronics, and I
> am familiar in configuring computers (clusters, application-servers,
> etc.). I am also familiar with most CAD systems, both 2d and 3d.
>
> I think we can manage it to build such a machine with the documents we
> have on cnc, and the EMC-software (of course we need to feed it with
> nc-code, but that's not such a big problem). What we would like to know
> is, is it possible to build a EMC-machine that's controlling servomotors
> and has something like feedback from the X and Y axis about posistion. Or
> are servomotors accurate enough to reach a 0.1 mm accuracy??? We couldn't
> find a document which describe's the use of encoders to give the exact
> position of the X or Y axis.
>
> It might be a stupid question, but I had to ask it in order to narrow the
> search area and read area.
>
> thanks in advance
> AJ Hettema