Help - Laser cutting shakey wobbly lines

Hey laser people, maybe someone can point me in the right direction.
I don’t know how long its been doing it but the other day while setting up my camera I noticed that I am getting wobbly lines on opposite sides of 1" circles. The machine is about a year old, not a lot of hours, 100w 6090.

-Checked for binding on my X Axis (left <> right) and it seemed smooth.

-I thought maybe it was the belts stretched, so I checked and adjusted them all. Its my understanding that they should be tight but not so tight that they sing when plucked. and just enough to twist them 90 deg.

-I thought maybe its a loose focus lens, so I took it out cleaned and put back. my machine didn’t come with a rubber for the lens. I would like to get one, any suggestions/links? its a 2.5" lens and the head is a 25mm slide type.

-Thought maybe it was a loose mirror, so I checked them all, made sure nothing was slack and did a re-alignment just to be safe.

After all that its still doing exactly the same. Any ideas?

How fast was this? The 900mm axis is long, so if these were run relatively quickly, you could get that same “strumming” on the axis itself. I would check your Y rails for any debris, and check the Y axis bearings to make sure they aren’t binding anywhere.

Thanks Oz, That pic was of one I did at a high speed (I think it was 200mm/s) to see if it got better or worse, but it does it the same at 65mm/s which is a normal cutting speed for me.

I checked out the belt gears & spider coupler for Y Axis (front-back) and everything there is tight. I guess I can try removing the small drive belt on Y and see if the axis is smooth.

Gremlins Suck! I really want to start playing with the camera but the boring adult in me says I need to fix this first.

The facts:

  • It is always the same spots on the 1" circle (upper and lower hemi) cut. Only changes I seen are if the circle is run clockwise or counter and even then it looks the same but mirrored left-right.
  • Does not matter where I place the cut on the (600x900) bed.
  • Speed does not make any real difference in the outcome.

The above rules out electrical interference, its got to be mechanical or maybe settings, right? I would think an electrical interference issue would be on all the circles/lines.

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Progress Maybe, If you are having this issue, try loosening your belts.

Well the way my machine is put together removing the Y Axis motor/small belt would have been a pain. I didn’t want to remove the Y belts, but decided it would be easier then the motor.

I did it in steps, One full turn of all 4 screws at a time and run a test cut. After 2.5 full turns the wobble is much less noticeable. The belts seem a lot looser then I would expect them to be compared to my 3d printers. I haven’t tried running any full projects yet so we shall see if this was the issue all along.

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I had similar wobble issues to yours that seemed elusive for a long time. I tried adjusting belt tension and even changed the x-axis rail but the wobble remained. What ultimately did the trick was removing the x-axis belt and blowing all the dust and debris off the belt and the gear. I re-installed the belt and tensioned correctly and haven’t had an issue since. No guarantees this will be the fix for your machine but it worked for me.


Hello there,

I had the same problem cutting small objects. The setting that worked fine for me was the attached signed values.Adsız

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Another potential cause of wobbly lines is a loose focus lens getting blown around by an air assist. Had that happen once, cause all kinds of frustration.

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Hi Metin! Where’d id you find these settings? / Andreas

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You can find those in LightBurn in Edit > Machine Settings.

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I had this happen to me. I hope that you have fixed it, with mine it was a mirror locking/round clamp screw that squeezes behind the mirror that had come loose (second mirror). The wobbles were from the mirror vibrating


Thank you very much for this advice.
After I changed the stepper motor driver, I have had the same problems.
By setting these three parameters, the machine became absolutely perfect.

I dont know what I just changed or why but who cares it worked! Thank you so much