Machsupport Forum
Mach Discussion => General Mach Discussion => Topic started by: AllenJ on December 03, 2013, 05:28:02 PM

recently added a cnc rotary table to my mini mill. Having a problem with my settings. I've made most of the config. settings I've found here. When I move the table with a G01 code or code from a wizard, the table rotates beyond the desired stop point, and continues to rotate. I'll try and post the .xml file. Any help and suggestions will be appreciated.

Usualy the rotary table is configured in degrees.
Thus,
G01 A 360 F1 would have the table rotate 360 degree's at a feedrate of 1.
Not sure what motor is driving your roatary table,ie; you need to tune the A axis just like the other axis's calculating the appropriate number of steps per degree, enabling it, and tuning for acceleration and velocity.
All in the manual.....
RICH

Rich,
The rotary table has stepper motor. "A" axis is configured for angular not linear. I used mach 3 to set the steps per and when told to "go to zero", it does. I have the manual printed and I've read and had all the checks that I believe are applicable. What else could it possibly be?

Allen,
Your steps per unit for the A axis are 10000.
You would have a gear ratio of 1800:1 which dosen't seem correct.......
ie;
200 steps per rev for motor x 10 micro steps x 1/360 degrees per rev x 1800 gear ratio = 10000 steps per degree
What is your gear ratio for the rotary table?
I know my Sherline is 72:1 ( 400 steps per degree) and for my Klinger it's 180:1 ( 1000 steps per degree).
RICH

Rich,
Admittedly that whole calculation thing is confusing. Here's the data I got for the table.
36:1 worm wheel (gear, I guess)
max angular velocity 30 deg/sec
max angular accel. 250 deg/sec
rapids over 180 deg/sec
nema 23 stepper w/ 1.8 deg steps
7200 full steps per revolution
backlash within 15 arc minutes
1 amp winding current or .5 amp full winding current.
So, you're saying the answer is in here somewhere?

BTW,
Rotary Resolution is 1/ steps per degree.
Linear conversion:
1 second per inch of distance = 0.000004848"
1 minute per inch of distance = 0.00029888"
So the Klinger at 1000 steps per degree has a resolution 3.6 seconds and at 1 foot that equates to a linear change of 0.00021".
Just some stuff, ;)
RICH

So, you're saying the answer is in here somewhere?
Your steps per unit:
200x10 ( i assume your are microstepping )x (1/360) x 36= 200 steps per unit.
For tuning ( same as the yo tuned the other steppers...)
Start with a low velocity say 5 and accel of 1, then just double the velocity until it skips. Then reduce the velocity at skipping by 40%.
Now start increasing the accel until it skips .
That should get you in the ballpark quickly and you can refine later.
RICH

Rich,
Problem solved. Adjusted velocity and acceleration, now I'm in business. Thank you for your help.