Low cost Servo/Stepper/CNC controllers? HELP! Questions too!

[Ralph Seguin <rpseguin-at-yahoo.com>]

I'm on a very limited budget, and I am looking for
inexpensive (??) PC based (PCI) 4+ axis controllers (3
axis + rotary table + ...?) for use with EMC (or other
softare in Linux, DOS, ...) for:

-fixing/retrofitting my existing Bridgeport mill (has
an OLD Retrotek 8800 CNC controller that doesn't work
well).  The mill already has precision ballscrews, and
DC permanent magnet servo motors.  This is one of my
top priorities.  This current CNC control reads out
and moves in 0.0001" increments, and I'd like
something at least as good (but WAY better for the
computer hopefully :-)

-Controlling a 3 axis stage that (currently) has
stepper motors on it.

-Doing some experiments and making some motion tables
with servo motors (DC, AC, brushed, brushless, 3
phase, ...) and stepper motors.


I know that there are some nice boards out there for
$800+, but that is beyond my budget.  Anybody have any
suggestions?

If I can get a good deal on 3 to 5 PC based motion
controllers.

I know that I've got myself into an expensive hobby
here, but we have to save our money for the bills now
:-(

Questions:
-What board(s) should I be considering?  (especially
for the Bridgeport retrofit).

-Am I insane to expect to find something cheaper? (I
guess I already know the answer :-)

-What stepper motors (or servos) and controller would
be good to use for driving a 3 or 4 axis mill or stage
(say 20"x20"x8" travels)?  With Acme screws?  With
ballscrews?  Say with 50lbs of table + work.


-How is this project going?  What will the cost be for
boards?
http://www.unibell.co.za/servo.html

-Any other public servo/stepper/cnc controller
projects like that?


Thanks!
-Ralph
rpseguin-at-yahoo.com




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