One year or so ago i purchased stepper motor package, i have been using the three axis x y z to date with no problems or failures using V carve pro and Mach3.

Several weeks ago i got the bug to set up a 4th axis, made 4 jaw chuck and live center with tailstock, activated the 4th drive with full steps of 200. the jaw chuck is direct drive w/ a flex coupling and several things don't add up!

 1. Getting full rotations on diameter with Simple Cylindrical Wrap  when drawing on 50% or half of the diameter. as seen on mach toolpath.
 
2. Setting full step, half,1/4, 1/8  does effect the rotations but still have the rotational thing of multiple rotations.

3. Wrapping around x or y in post processor in V carve.

4. Using radius for feed rate and A rotations enabled in mach and rotation diameter of .0001.

After cycle start x or y z crawl to a stand still when A axis is activated during machining operations.

 I have visited both mach and vector forums and at this point i am totally confused.


thanks in advance

tenhrdaz

Sounds to me like your steps per on the 4th axis are set wrong.  What is it set at and how did you come up with the number of steps per rotation for it?

Brett

360 deg. * 1.8 = 200 physical steps, this seems logical to me sense i am using a direct drive from the stepper motor ?

But is your stepper drive full step? Also it is steps per degree so if you had 200 stepss per 360 degrees that would only be 0.55555 per degree
Hood

2. Setting full step, half,1/4, 1/8  does effect the rotations but still have the rotational thing of multiple rotations.

You NEVER change your microstepping to try to adjust distance traveled.

As Hood said, you need to set it to steps/degree. I'd set it to 1/8 stepping and 4.4444 steps/degree.

THANKS TO ALL

Stepper drive was set at full step,  re-set it to 1/8 stepping and 4.4444 steps/degree. issue with slow down  an full rotations is gone, why 1/8 stepping and how did you arrive at the answer?

I miss understood the whole step concept, I used stepper motor @200 =360 degrees of rotation.

Seems that the old dog can learn new tricks again many thanks to all who helped
Richard

why 1/8 stepping and how did you arrive at the answer?

1/8 stepping is usually much smoother running then full step.

1/8 stepping gives you 1600 steps per rev.
1600/360 = 4.44444