Im putting together my fist hot wire cnc will rack and pinion work or should it be lead screw? Any help or thoughts.

I have one built and I believe most that you find including commercial setups are leadscrew. I think with leadscrew your tolerances over the long span would be better. How big are you making this?
John

Right now its 12'x 3' I would like to extend it to 16' x 4' .I think the leadscrew is going to be big buck on the 12' or 16' run.
Mark

Mark,
For running that size you will probably need a full frame to support what ever you mount for motion. Mine is small for cutting wings and other items. Do a search for foamcutting and you will learn quite a bit. I did not bookmark some sites but they where cutting large blocks and one was for making sports car bodies and then glassing. I believe it was in the land of OZ.
Good luck, John

Man, I would hate to have the bill for a 16' ballscrew!

We have a dept. at work, that cuts those things, I've never seen them ship one out that long.

You would have some serious whip!


.

You'd be fine with belt. Check out Hotwire Direct machines.

I have done several with belt. No whip, low forces involved, low speeds.

I used direct drive pulley, with 1/16 microstepping. My pulley was about .5" OD.

Oh, and cheaper, easier, lower maintenance than leadscrews.

From directs website specs:

http://www.hotwiredirect.com/products/cnc-foam-cutting-machines/cnc-foam-cutting-machine-8700/

Cutting Capacity
106″ x 51″ x 105″ (269cm x 130cm x 266cm). Wire is 105″ long. Other sizes available.
Resolution
0.001″ (0.025mm)
Accuracy
±.002″/foot (0.0167mm/m)
Drive Motors
Five 160 ounce/inch (1.8kg/cm) AC servos, 4000 counts per revolution encoders
Drive System
X & Y axis timing belt drives, precision sealed bearings ride on hardened ground rods
Max. Cutting Speed
55″ (140cm) per minute
Max. Rapid Speed
1500″ (3,810cm) per minute
Cutting Wire
Up to 6 - .014 (.355mm) wires
Power Required
220v single phase 50-60hz, 20 Amp
Warranty
1 year on all electrical components, 3 years on all mechanical components
Tech Support
Unlimited support at no charg

Thanks Ill check it out.
Mark

I have been looking at Econobelt.What about belt size teeth pre inch pitch ect..Any help would be great.
Mark