Where to begin? Retrofit a Stepper Control to a Mill-Drill?

[pfeist]

Help! I don't know where to begin!

What I want to do: Turn my Mill-Drill ( 7"x18" or thereabouts) into step-motor driven CNC.

What I DO know how to do: convert to Ballscrews (although I want to do that LAST.. I've lapped the acme screws and adjusted out almost all backlash.. it runs smooth, and I'm POOR).
I know how to mount stepper motors, etc.
I know the mechanicals.

It's the leads off the steppers... there's where I get clueless!

I've got a vocational degree in Machine Tool Technology... and I spent two years learning how to program a Bridgeport Boss 8 control... but that was 12 years ago, and I'm lucky to remember the difference between G00 and G01. I'm perfectly comfortable re-learning Gcoding for 90% of what I want to do. Yeah, CAM softare is great.. and I'll do it eventually, but to START, I just want to run some fairly simple cuts that I can code myself.

Somebody please check me here...
What I THINK I need is this;
A PC (of course) with a parallel port.
One of a large variety of software packages to send commands (from my Gcode) out the Parallel port to a controller (for example, DeskNC for Dos).

That said controller I know darn little about.. I've seen ads for the $3000+ setups from MicroKinetics and AhHa!, and then I've seen kits from LiniStepper and HobbyCNC, and finsihed units from StepperWorld for under $200 for all three Axes.

Somebody please throw me a bone here... How do I tell which kind of controller to use? (OTHER THAN it has to be capable of handling motors of sufficient amperage/Oz-in.. that part I got...).

Given a PC, and something like DeskNC or similar software, what needs to go between the parallel port and the Stepper motors?

I'm not afraid of solding things to boards... as long as I have good instructions on what goes where...

Any other gunsmith/machinists with very little electronic knowledge who can recommend some INEXPENSIVE parts to retrofit my Mill-Drill to 3 axis (or 2 and half axis, and I'll add the "other half" later) , I'd be grateful!

Paul F.

[marvinstov]

You might check out TurboCNC for software (shareware). And check out Xylotex for a driver depending on which motors you want to use. 3 Axis for about $125.00 and good for 2.5 amps per phase.

Marv

[RotarySMP]

Any PC above a 486 DX with a parallel port. Preferably any Pentium class machine.
Dos.
Running TurboCNC, Great program, great support, shareware, simple to install and use, good selection of canned cycles as you want to do manual programming.
http://www.dakeng.com/turbocnc.html

Probably Geckos G201 stepper drivers, as Xylotex might be a bit underpowered for this size machine.
Muscle power supply.
Two phase stepper motors.

TurboCNC converts your G code to step and direction signals, so each axis gets two pins on the printer port.

Say X axis is Step pin 3/direction pin 2. There is a menu in TurboCNC to instruct the program how many axis you have, what they are called, which Parallel port pins they attach to, and what is the linear/angular move for 1 step.

The X axis Gecko will be connected to these two pins. It also needs to be connected to a 5V DC source for it's logic circuits. You can tap this from the computors game port. The last thing it needs is muscle power, provided by a 20-70V power supply. Marris has a good white paper on the power supply here.
http://geckodrives.com/support.htbml?order_id=

The motor is connected to the Gecko with four wires.

You then set the geckos to the motors max current per the instructions.

The gecko gets mounted to a heat sink.

Easy as that. That will get an axis running.

You will then spend 1000 hours mucking around with housings, enclosures, wiring, limit switches, E-stop, spindle encoders, etc

[snoopy]

One of the more dfficult things to do is to build a z-axis. If you need a z-axis. please look at the stepper I have posted with a lead screw.

Thanks

http://cgi.ebay.com/ws/eBayISAPI.dll...ADME:L:DS:US:8

Item number: 3810437968

[snoopy]

PS also one of the more intersting forums I go to is. luberth.

http://www.luberth.com/cstep/

this helped me build mine.

[HomeCNC]

You have two choices for converting the Z axis.

1) use the existing Rack and pinion and place the servo/stepper on this. (could have to much backlash)

2) remove the Rack and pinion and power the spindle it's self. (this is what I did)

[pfeist]

Thanks to all who replied!
Particular thanks to RotarySMP... that clarified a few things greatly!
I've got a lot of thinking to do (and measuring things) before I start, but I'm getting on the right track!

Paul F.

[swarfmacdaddy]

gecko g 201s!! You can run a greater range of motor types at a wider speed range with these drives than anything around! And they just plain look way cool. (I dont know why people always mount them inside an enclosure, mine are on the outside where the can be seen.) And you cant beat the versatility for the price,

[snoopy]

Hey if anyone would like a model of what to use, this is my first unit, very simple but effective contruction.

http://cgi.ebay.com/ws/eBayISAPI.dll...ADME:L:DS:US:8

James

[snoopy]

I can post the cas models which I have in vrml
If that would help

James