Laser turns off for some areas

I’m using lightburn 1.2.0 and need some help please with two issues:

  1. For some reason, the laser keeps turning off on certain sections. What’s even more odd is that I tried the same design with two different sizes 4" and 4.7" wide and the results are totally different. I watched the laser run and it turned off at different sections based on the size of design. I ran the design twice and the laser turned off at the same sections.
  2. For the larger size design (4.7"), the laser is burning squiggly lines sometimes, see photo with red circle highlighting it. Also the results mirror the design for the small size 4", but for the large size the results are off.
    Would appreciate it if someone had some insight into this. Thanks in advance.

    5 with glue tabs.lbrn2 (29.6 KB)

What photo(s)?


sorry, new to forum, I have uploaded photos

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Might want to let us know what kind of machine you have, that helps.

If you can ‘drop’ the .lbrn2 file for us to examine, it might help also.

However you created it, it doesn’t look right.

Is this a new machine.?

Generally when this happens, it’s a lose connector… at least for the laser turning off and on.

The squiggly lines are probably not related to the laser issue, but again that usually is related to belts or something being lose.

Double check connectors and it’s mechanically correct.

Good luck


Thanks for the response Jack. I’m using a Ortur LM pro S2 and I had uploaded the lbrn2 file.
This is not a new machine, I’ve had it for 8 months, I’ve mostly been engraving stuff with no issues, haven’t really cut much stuff until now.

Thanks, I will check the connector and belts. If these things were the issue, would it burn/cut the design with the same issues every time? I’ve ran the laser 5 times now and it turns out the same every time with exact problematic areas.

This looks like something mechanical. Check that the pinion on the stepper motors are proper secured. There are likely two grub screws on each pinion. Make sure one is secured to the flat portion of the stepper shaft.

Also recheck belt tension.

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Thanks for the insight. Solved the problem of the squiggly lines by tightening the y axis belts.

After so more testing, the issue with the laser turning off on some areas is because the lines are not joined together. I tried auto join selected shapes, it joins some but not all of the lines together. It’s very mundane and time-consuming to manually join each line together, still trying to figure out a more efficient way to do it.

Have you tried “Edit → Autojoin selected shapes” ?

Even when the lines are close, I don’t think I could distinguish that the laser is off for that moment?

What brings up this conclusion ?

Might want to post the .lbrn2 file if possible for others to examine.

We can make a better suggestion if we can see the problem and mess with it locally.