OK - you convinced me - was "Automated "Manual CNC"

Thanks for the detailed response!

It sounds like a combination of heat build-up and lack of smooth
contours is what gets me.

This setup would probably be excellent for situations where cutting
does not take place while the table was moving - like drilling an
index plate - move to XY, drill down, drill up, move to XY, etc.

But for smooth continuous cuts, the advantages of full CNC are now
evident.

But my problem is now: can I achieve full CNC with plain linear
encoders, plain leadscrews, and a CNC program like one of those
listed below?

> P.S.
> There are a few s/w cnc controls which support closed loop

operation.

> Search previous posts for more info.
> 1.EMC (NIST)
> 2.DeskNCrt (Carken)
> 3.Microkinetics millmaster/lathemaster/Instep library
> 4.MaxNC-Servo (really a closed loop stepper)
> 5.SimpleStep (JRKerr??)
> 6.PCNC (Bestsoft)requires expensive motion card

A) I would like to use a plain DC motor coupled to the lead screw
through a gear reduction. They would be interfaced with the PC
through a driver where the speed could be varied, accelerated,
decelerated, etc. Is this do-able or do I have to buy full fledged
servo motors?

B)I would like to use linear encoders like that of digital readouts.
I know the update frequency is not quite up to speed, but if I adjust
my accel/decel & top speed to compensate for this, could I still use
them? I would have to build and interface between them and the PC. Is
this do-able or do I have to buy faster encoders?

C) What are your thoughts on not converting to ballscrews with table
feedback?

D) Would EMC be a likely contender with this setup?