A-Axis (4th axis) to use a CNC router as a lathe

Hello all:

I am a newbie with a Probotix Comet CNC router and I added a 4th rotary A axis with the rotation aligned to the y axis of my table.

I have been using my comet for some months now with Vcarve pro and manually and it is going great!

But now I need to cut about 30 qty 3" O.D. 2.75" I.D. acrylic cylinders (make them shorter) and need a perfect cut.

I tried many times using a bench saw but the cut is not perfect and I don´t have a lathe.

I am sure it will be perfect with the CNC router as I have been doing perfect cuts on acrylic but with only X Y and Z movements.

I would like to be able to start rotating the A axis and then manually move the x, y, and z axis with my MPG pendant so my router cuts the acrylic as if it was a lathe.

Is there a way to put a button on the GUI screen to start turning the A axis and then adjust the rotation speed before moving the other axis?

Or is there a G10 code I can input on the command line to start the rotation and then I move my router?

Controlling my router as a lathe would allow me to do a lot of stuff

Also, I am using Vcarve pro and would like to be able to cut using the 4th axis to cut round parts. I also have meshcam but I have never used it.

Any help is much appreciated!

THANK YOU!

Rod

Halo,

if your rotary axis is aligned with the Y axis of your table, it should be an B axis!

But I would recommend to add the B axis as spinlde configuration, then you can start and stop it as required.

Or go to MDI mode and say something like G0 B100000000000

It will turn quiet a while, with additional MDI commands you can move your axis.

Norbert

thank you! I will try it. I hope this works at the same time I jog the other axis.

Hello again

Bad luck

I tried the MDI G0 A100000000 to turn my A axis but it gives me the error that it cannot move an axis that has not been homed, but as the A axis is a rotary axis it does not have any type of limit switch to be homed.

I am hoping there is a way to add a button to the GUI where just like I can start the flood motor or the spindle motor I could start the A axis and then by jogging, use the machine as a lathe.

THANKS
Rod

Have you looked here...

linuxcnc.org/docs/html/config/ini_homing.html

3.12. Immediate Homing

If an axis does not have home switches or does not have a logical home position like a rotary axis and you want that axis to home at the current position when the "Home All" button is pressed in Axis the following ini entries for that axis are needed.

SEARCH_VEL = 0

LATCH_VEL = 0

USE_INDEX = NO

HOME_SEQUENCE = 0

Rick G