[BallisticFab]

Since we have the new laser up and running I was planning on converting our PCNC machine to a 4th axis tube plasma, but they went out of business. I'm using all of their latest winCNC and ATHC stuff (which worked 1000X better that the old crap..), and would like to know how to retrofit a stepper driven rotarty spindle of sorts. Am I out of luck?

Jeff

[Torchhead]

Define "of sorts". You can do it manually by unplugging the cross axis Motor driver from the X motor and build a rotary axis that you plug the X side into. You then have to do some math and determine the circumference of the pipe (PI times the diameter) and recalculate the steps per inch current X setting and convert that to move the circumference of the round object the same distance. I don't think PCNC supported a 4th axis in there older controllers. The WINCNC can handle 4 (or more) but if it has nothing to talk to it is useless.

I think you are out of luck to have a totally independent 4th axis but you can do it the way described above. The challenge is to develop the artwork to the right size (imagine the circumference unwrapped and laid out flat) and then turn X into a rotary axis (and lock the actual X gantry axis over the centerline of your horz rotary axis.

Once you figure out all the ratios of the rotary head they become a constant in the steps per inch formula and you just have to know the pipe diameter.

Take a look at http://www.cncpartskit.com/tubecutting.html# for some ideas on tube cutting.

It's a lot easier to do with a fourth motor and driver but you can do it with 4 motors and just unplugging/plugging the X driver.

TOM CAUDLE
www.CandCNC.com

[BallisticFab]

I program my full 4 axis mills all day long, that's not a problem.

Where do you think that I could find a simple stepper driven rotary axis? I am not opposed to loosing my x or y axis since I won't ever use this table for anything else. Any ideas?

[BallisticFab]

Can anyone recommend a 4th axis here please?