My chuck creates gaps

LightBurn Software Questions
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1

Hello!

I’ve recently purchased an Omni X UV laser and am having loads of fun with it!
Flat images come out amazing:)
Now I’ve been struggling for hours with the rotary and can’t get it to work properly.
The main problem is that the end result has gaps in it.
A big clue as to where the problem originates seems to be that instead of rotating smoothly it jitters back and forth to do a few lines here and there.
I’ve set up a simple test with a standard box 1mm wide, going around a ring.
Can anyone help point me in the right direction? This is my first experience with a chuck, so I hope it’s a rookie mistake.

Some info that might help:
-The same things happen with an image
-Split size can go as low as 0.023mm, this shows the same behaviour but smaller (harder to see on video)
-Optimization settings Cut in Direction Order/Reduce Travel Moves/Reduce Direction CHanges don’t seem to do anything

Any input is welcome!
Cheers
Erik

Chuck Settings
Chuck Settings683×733 36 KB

Picture Endresult
Picture Endresult960×1280 136 KB

Rotary Settings
Rotary Settings502×610 20.7 KB

2

What happens when you hit the “Test” button?

3

It makes a perfectly smooth circle,
it feels software/settings related

4

Most likely, the maximum acceleration and speed config settings for the rotary axis (Y? A? U?) are too high by at least a factor of ten.

Cut them down dramatically, see if the situation changes, then tune for best results.

5

Thank you for your idea, I divided these 4 parameters by a factor 10:
Min/Max speed, Acceleration Time, Return Speed.

There is one huge gap and loads of small ones.
It also overshot by a few degrees/centimeters, so it kept going when it went round once already.
The diameter is 22mm, I drew a line of (22*3.14=)69mm, that checks out..right?

Picture divided by factor ten
Picture divided by factor ten960×1280 104 KB

6

The Acceleration Time seems like the inverse of the acceleration value used in other controllers, so:

  • Reset all the values back the way they were
  • Multiply the Acceleration Time by a factor of ten

If the rotary is not moving smoothly, then it’s not maintaining the correct position, so that’s not surprising.

7

Happy New Year Ed!
Doing both things you said made a closed circle with no gaps!

Min speed = 50
Max speed = 500
Acceleration time is 10.000 (!)
This made it painfully slow, and the individual lines are still showing, but this is something I can fix with trial and error optimization

Thanks a bunch :green_heart:
I hope your start of 2026 was a good as you made mine :rainbow:

8

Yay! :grin:

For Fill areas, those can be the same value, because the controller uses the Overscan area to get up to the Max speed.

I was referring to the speeds & accelerations in the Machine Settings for each axis. Those will let you maintain the overall speed for the X axis while limiting the rotary speed / acceleration (which is less critical, because the laser beam is off during those motions). Although you can save / restore those settings in lbset files, you must (remember to) load the appropriate file for each setup.

That could be a matter of getting the Line Interval closer to the width of the focused spot or, more accurately, the burned area it creates.

Now you can tune for best picture! :grin:

9

That’s interesting, I didn’t know that!

I’ll go on a fiddling-with-settings adventure now, thanks again!