Safety issue after LightBurn update

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Hello LightBurn Team and community,

I would like to report a serious safety-related issue I encountered after updating LightBurn, which I believe deserves attention due to its potential fire risk.

Machine: Creality Falcon Laser 10W (diode)
Controller: GRBL
Operation mode: Offline (SD card)
LightBurn version: 1.7.0.4
OS: macOS (older version, cannot update further)

Description of the issue

After updating LightBurn, my machine began exhibiting dangerous behavior specifically during image engraving and filled operations. When running a job from an SD card, the laser head suddenly moved rapidly toward the side of the machine and repeatedly hit the physical end of travel while the laser remained ON.

Summary

This did not occur with simple vector cuts, only with raster/image operations.

Fortunately, I was present and noticed the abnormal noise immediately. However, the laser remained active at that position long enough to severely char the sacrificial wood, which could easily have resulted in ignition if unattended.

Root cause (identified after investigation)

The issue was ultimately caused by the fact that my old device profile was NOT GRBL, even though the machine itself is GRBL-based.

Earlier versions of LightBurn appeared to tolerate or silently compensate for this mismatch.
In LightBurn 1.7.x, the software now generates stricter G-code, and this legacy profile resulted in incorrect raster motion and overscan behavior, producing movements outside the physical workspace.

Once I created a new, correct GRBL device profile, the problem disappeared immediately.

Safety concern

From a safety perspective, this behavior is concerning because:

  • The software allowed generation of G-code that moved beyond the known workspace

  • The laser was not disabled when motion became invalid or stalled

  • No warning was presented when using a legacy / incompatible device profile

  • Offline (SD card) operation removes real-time supervision and makes this especially dangerous

This exact scenario (laser stalled or stuck while still firing) is a well-known cause of fires in diode laser systems.

Suggestion

I strongly suggest considering one or more of the following safeguards:

  • Clear warnings when opening or using legacy device profiles after major version changes

  • Validation that the selected device type matches the controller used (especially for raster jobs)

  • Explicit warnings for offline raster engraving

  • Optional automatic laser shutdown when abnormal motion or boundary violations occur

I am sharing this report not as a complaint, but because I believe similar situations may have contributed to reported fire incidents in the community.

Please let me know if logs, configuration files, or additional details would be useful.

Best regards,
Carlos Silva

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Hi Carlos, sorry to hear you had an incident - your post reads as AI-generated, and we don’t do that here, so I’ve hidden it for readability.

Given that you were running the gcode off a SD card, can you access the SD card and upload the .gcode file for us to review?

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All of these are impossible to implement.

  1. There are no legacy profiles. Profiles haven’t changed. If your laser profile has been wrong before, it stays wrong.
  2. It’s impossible to get the laser type from the laser. There are thousands of different boards, using hundreds of variants from 3-4 original CNC firmware projects. It’s not possible to detect the firmware type and version correctly.
  3. How would you detect if someone is doing an offline engraving or not? Also impossible.
  4. LB can’t detect any abnormal laser behavior, especially for gcode machines. The protocol is a one-way stream and there is no notice of abnormal behavior that LB could detect. If the laser stalls and fires, it just does so, there is no message to LB. You would need an intelligent camera to detect this.

So, bottom line in my opinion: none of those options would release the user to

  1. configure the laser correctly
  2. use the correct project configuration
  3. observe the laser constantly while in operation

I understand your points, but I don’t think LB can do anything about it. The user has to do it.

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realmente foi gerada por IA, pois meu inglês é ruim e o assunto era complexo para relatar sem este autíxlio.
solucionei o problema justamente com o auxílio desta IA e queria relatar aos participantes um problema que enfrentei e a solução.
Oblrigado pela atenção.

It was actually generated by AI, as my English is poor and the subject was too complex to explain without this assistance. I solved the problem precisely with the help of this AI and wanted to share with the participants a problem I faced and the solution. Thank you for your attention.

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o que eu fiz de errado (somente eu, não o LB), foi criar um perfil errado, que funcionava nas versões anteriores e passou a dar erro violento depois de atualizado para a versão 1.7.
Para auxiliar outros, não tão espertos como a maioria deste forum, é que fiz a postagem.

What I did wrong (only me, not LB) was create the wrong profile, which worked in previous versions but started giving serious errors after updating to version 1.7. I made this post to help others, not as clever as most of this forum.

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