I’m trying to mark a degree scale around the edge of a flat disc using a fiber laser with a LMCV4-FIBER-M controller and a rotary chuck attachment.
Setup:
Disc diameter: 180 mm
Lens: F163, working field 110×110 mm
Scale: major ticks every 5° (7 mm long), minor ticks every 1° (4 mm long), numeric labels every 10° (tangential, counting 0 / 1 / 2 / … / 35)
Note: labels are section numbers 0–35, not degrees
Since the disc is larger than the working field, I need to mark it in segments, rotating the chuck between passes.
I previously tried EZCad’s Power Ruler plugin, but it causes EZCad to freeze or crash.
My questions:
Am I correct that the right approach in LightBurn is to use Repeat Marking together with Variable Text — one pass per tick group, rotating the chuck between passes?
In EZCad’s Power Ruler, you had to enter the workpiece diameter so it could calculate the arc length per degree. Where is that configured in LightBurn when using the rotary setup?
Any help or documentation pointers would be greatly appreciated. Thanks!
The reason is that I need deep engraving — a shorter lens produces a much higher energy density at the focal point, which is essential for cutting deep into metal. A longer lens simply can’t deliver the same power concentration. On top of that, a shorter lens saves time, as fewer passes are needed to reach the required depth.
As for the circle distortion — even with a longer lens and perfect calibration, there will always be some minor deformation of the circle due to the way the X/Y axes interpolate the shape.
Using a rotary axis eliminates this problem entirely. Instead of the laser head drawing the circle through two-axis movement, the workpiece rotates on its own axis while the laser moves along a single linear axis. The circle is formed by the rotation itself — so the result is a perfect circle with zero distortion.
Given my limitations on such a broad subject, I can only point out options such as drawing a scale in degrees based on the face of a clock.
I’ll start with one created by @thelmuth and others that I used when I was drawing some clocks.
Another way to do this would be to just draw a straight ruler and use rotary marking. If the ruler is 360mm long and the bottle circumference is set to 360mm the marks will be the same as degrees when it’s run on a turntable. Select all the ruler marks and run them with a small split size so each one is done individually with a move in between. Then select all the numbers and run those separately with a wider split size.
More then one way to skin a cat. No matter what the cat ain’t happy.
The nice thing about the way I suggest is it is not so dependent on getting a hyper accurate measurement. It will always turn 360 degrees and always print 36 scales so the accuracy is self correcting instead of compounding.
