Laser with rotary for tube cutting

[PMF]

Folks,

I hope that this is the right forum to ask this question. We cut tubing (2in to 1in SS) using a laser and a rotary fixture. The controller is an Anorad II. I am still new to using this type of setup. But when we cut the tubing the distance we specify to travel around the tubes circumference (spinning the collet) does not equal the true circumference of the tube. If I tell it to rotate the tube a distance of 6.28318 (circumference of 2" tube) it will rotate 360 plus 1/4" or so. I cannot figure how the machine is calculating the distance. The encoder has 100 lines of resolution, and is attached to a 90:1 gear box. Any ideas on why things are not adding up. I hope I have explained what is happening well enough.

Thank you very much for the help!!!

[kawazuki]

Maybe it needs internal circ. not external?

[PMF]

Kawazuki,

Thank you for your reply. Unfortunately using the internal circumference does not work out either. I am at a bit of a loss.

[youngjim]

6.28 is approximately 2*pi radians, is it working on that?

Jim

[PMF]

Hey Jim,

Thanks for the reply. I worked out the resolution of the rotary fixture in degrees and then converted to radians. It appears to be very close. So we are going to try it and see what happens. I agree with you that it is probably radians.

Thanks!

[youngjim]

Piece of cake. Heh.

Jim