Hi mates:
I'm planning to build a CNC foam cutter similate to this:

http://www.8linx.com/cnc/ (http://www.8linx.com/cnc/cnc.htm)

But i'm very confused with the torque of the stepper motors: I will use unipolar motors, and I'd like to know wich torque should i choose. 30 oz/in is enough, do i need a 100oz motor or higher??

Thanks.

I noticed that these guys are selling small 40oz/in motors for foam cutting. There must not be much force required to move the wire through the foam.

My only thought is that you can get 100 oz/in motors pretty cheap so why not get the extra power?

I noticed that these guys are selling small 40oz/in motors for foam cutting. There must not be much force required to move the wire through the foam.

My only thought is that you can get 100 oz/in motors pretty cheap so why not get the extra power?

Actually. the wire never touches the foam so zero cutting load. 30oz-in would be bare minimum. 100oz-in for heavier commercial production machines. 50-60oz-in for the lighter duty hobby type machines is fine.

Dave Rigotti
www.hobbycnc.com

I have read that with hot wire foam you want to use the slowest speed, and lowest temp for the wire. Just 2 cents.