A forum post inspired me to think about the possibility of connecting a turntable to a laser to possibly create a series production. This resulted in a small feasibility study, which I was able to implement in just under 30 minutes. The prerequisite is a mainboard that has a driver for the z-axis, unfortunately most current mainboards no longer have this. However, older boards usually still have this slot. Newer boards with automatic z-focusing should have it again.
Procedure
The trick is simply to use LightBurn’s automatic Z-feed to rotate the table further. You just have to calculate which values you need to be able to move the table in a targeted manner. In my case, I used a normal stepper motor with a step width of 1.8° and an A4988 driver with 16 microsteps. This results in a number of 3200 steps for one revolution (360/1.8 × 16). Since LightBurn does not work with steps, but with distances/millimeters, there is still a conversion by the firmware in the setting of the steps/mm for the z-axis. In the firmware, I have entered 80 steps per millimeter (the number can be chosen almost arbitrarily, I have taken 80 to reduce the number of steps somewhat). This now means that the plate makes exactly one revolution when I tell the axis to move by 40 mm (40 mm * 80 steps/mm). If you would like to have different values here, you can change the steps/mm accordingly. In my example, I wanted to place four objects on the table, i.e., always rotate them by 90°, which I achieve with an infeed of 10 mm for the z-axis for each pass.
You can then test this with the following command:
G91 G1 Z-10 F200Note: In my case, the movement must be negative, as the firmware assumes that the axis can only move downwards as seen from the limit switch. However, this is a question of configuration, if -10 does not work, then it should work with 10.
In LightBurn you now have to activate the z-axis, the easiest way is to activate the relative positioning of the axis, because no homing can be done in the simple setup. In the layer settings, you can now specify the number of rotations with the corresponding distance according to the settings made. In my case, four passes with a 10 mm z-adjustment results in 4 objects that are 90° apart.
Pictures
This is what my test setup ultimately looked like, I tested it on a Sculpfun S10.
Downloads
Here is the file I used for the turntable: Download. There is a hole in the center with a flattened side to sit exactly on the motor axle. This must be adapted to the motor.
