Rotary Setup on LaserBoard

If you have a Rotary from LightObject or HM Laser Accessories, it should work directly off the board with the built-in drivers. Plug it into the A motor port on LaserBoard, configure, enable and setup in LightBurn. Rotary types/settings will vary and need to be dialed in based on their specifications, but this guide can be used as a general starting point.

Determine Your Steps Per Millimeter

Check your rotary documentation for the needed data. Gather the following information to begin:

  1. Review the Stepper Motor Specs for the Step Angle and note the corresponding steps per revolution:
  2. All C3D drivers are set to use 1/16 microstepping. If you are using an alternate external driver for a custom setup, check the driver documentation.
  3. Determine the reduction ratio of any gear being used on the rotary. Divide the driven gear teeth on the motor by the drive gear teeth on the shaft.
    Example: 10 teeth on motor pulley / 20 teeth on shaft = 2:1 Reduction Ratio
  4. Plug in the previously gathered values:
    (Steps per Revolution × Microstep × Reduction) / 360 = Steps per Degree
    Example: (200 × 16 × 2) / 360 = 17.77 Steps per Degree

Setup the Config File:

  1. Power off the C3D Board, remove the SD card and access on your computer using an editor such as Sublime Text. Do not use Notepad++.
  2. Find the # A axis settings.
  3. Change the delta_steps_per_mm (Ex: 17.77 calculated previously as Steps per Degree).
  4. Reduce the delta_max_rate (Ex: 6000 mm/min)
  5. If needed, increase the delta_current to 0.8 or 1.0. The board’s per driver max is 1.2 amps. Do not exceed the stepper motor max. Ensure the motors are not overheating after increasing.
  6. Decrease the delta_acceleration to between 50-200. Lower values prevent your work from flying off of the rotary or spinning too fast initially.
  7. Save your changes, safely eject the SD card, then reinsert into the board and turn everything on.

Test the Rotary

  1. For roller type rotaries, refer to the rotary documentation or use a micrometer/calipers to measure the actual diameter of the drive wheels in mm.
  2. Adjust the Rotary settings in LightBurn under Tools > Rotary Setup.
  3. Select “Chuck” or “Roller” under “Rotary Type”.
  4. Check “Enable Rotary”.
  5. Under “Rotary Axis”, select the axis which your rotary is connected to.
  6. For roller type, enter the previously measured wheel number into the “Roller Diameter”. (Ex: 54.25 mm)
  7. Enter either the diameter of the object to be engraved or its circumference and the other value will be automatically calculated.
  8. Click “OK” to save the changes.
  9. In LightBurn, go to the “Console” tab next to the “Move” & “Cuts” tabs.
  10. Once the laser connects, type G0 A360 in the command field and hit enter.
  11. The rotary should now make one full revolution on the wheel. If needed, use a marker to mark the rotary drive gear on the motor and a corresponding mark on the motor bracket to gauge and tweak as necessary.

General information on rotary setup in LightBurn and usage:


Many thanks for posting this Starla Fox. Hopefully it will make my setting up of the rotary much easier.

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