Third Circle Cut Always Goes Wrong

LightBurn Software Questions
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1

I’m running into a weird but reproducible issue with my laser (Omtech Polar) and I can’t tell if this is a LightBurn issue or an issue with the laser. Basically if I try and cut 3 or more circles on my laser at one time in a batch, the third cut will always go wrong in some way. If there are more than 3 circles it’ll do a weird little eye thing instead of a full circle. If there are only 3 then it’ll move slightly from the 2nd circle and then cut in the complete wrong place.

I’ve tried deleting and reimporting the device profile for my laser and disabling the optimization settings but neither has fixed the issue. If I only cut 2 circles then everything works fine. I’ve also tried creating the circles both inside of LightBurn itself and importing them as an SVG file. I run into the same issues in each case.

Below is an example. This cut went right to left and it only did the weird circle cut on the third one.

PXL_20250808_191030331
PXL_20250808_1910303311920×1446 354 KB

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2

Hmm, 100% repeatable sound like software.

Does it do the same if you rotate 90 degrees?

Howbout if you rotate 180 degrees?

Are circles/ellipses the only shape that does that?

Are you on networked connection to the laser? USB or ethernet or wifi?

Dose scale affect the issue? Run it at 50% scale = same result? Does the problem replicate if you run 6 circles at 50% size or 9 circles at 33% size

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3

It definitely does it when I rotate 90 degrees. I’ll try the scaling and more items to see if I get similar results.

I am running the jobs from a macbook connected via usb.

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4

Here’s the results with 6 half sized circles. It was the end of #4 and all of #5 when it went wrong

PXL_20250808_195143386
PXL_20250808_1951433861920×2550 558 KB

and 9 33% scaled circles. #4 and #5 are the wonky ones.

PXL_20250808_195157277
PXL_20250808_1951572771920×2550 553 KB

I also tried 2 circles with 2 passes each. The first circle was fine, but when it started the second circle, pass 3 it went wonky again

PXL_20250808_194416226
PXL_20250808_1944162261920×2550 390 KB

5

When I see this, I wonder if it’s a legitimate copy of Lightburn.

Did you make all of these the same way?

:smiley_cat:

6

I purchased the license with the laser, directly from Omtech. I’m pretty sure it’s legit. It’s activated for sure and on 2.0.2.

Screenshot 2025-08-08 at 4.03.00 PM
Screenshot 2025-08-08 at 4.03.00 PM489×600 79.5 KB

For the latest test I did make them all the same way. I made one circle and then used the distribute command to make the extra copies in a grid.

7

Did this work?

:smiley_cat:

8

No, that was what my latest pictures were from.

9

I went ahead and downgraded back down to 1.7.8. Issue went away. It must be something with one of the newer 2.x versions

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10

Please keep the problem project file (.lbrn2) and send an explanation of the issue along with a link to this thread so they can determine if there is a problem or not.

You should not have to downgrade to a previous version.

Maybe @gilaraujo can speed things up.

:smiley_cat:

11

Hi @TheDeadDreamer. Welcome and thank you for drawing our attention. :slight_smile:

Agree with @jkwilborn’s recommendation. Send an email with the “problem project file (.lbrn2)” to support@lightburnsoftware.com with a link to this post for context, and we will take a closer look.

2 Likes
12

I believe this was corrected on 2.0.03 RC2

Could you try this version - it installs on a different folder so 1.7.08 would still work.

13

Had a similar problem with circles and ovals. Tech help polite but didn’t solve. I installed an archived version, earlier version of Lightburn and the problem went away. My issue was on and after the fifth pass, it went Spirograph on me.