Printhead moves beyond limits before printing

Bambu Lab A1 Series Troubleshooting
1

Hi, I’m having an intermittent issue with my Bambu Lab A1, which is running the latest firmware.

This has now happened twice: right after sending a model to print (before the usual auto-leveling and flow calibration), the printhead moves erratically and seems to exceed its motion limits — specifically colliding with the filament cutter bar on the right side.

The model was sliced in Bambu Studio and appears normal in the preview. In both cases, I had cut a large model into two separate parts and arranged them on two build plates. When sending only one of the plates to the printer (with the second one still present but inactive), the printhead moved beyond the printable area before any heating or calibration began.

I canceled the print immediately to avoid damage. When I re-sent the exact same model to print again, the issue didn’t happen — the machine proceeded normally.

To rule out hardware issues, I manually tested the movement of all six axes via the touchscreen, and the printer respected all endstops correctly.

This suggests the problem isn’t with the model or hardware, but possibly:

  • A bug in how Bambu Studio handles multi-plate slicing?
  • Some corrupted gcode generation?
  • Or a rare firmware hiccup on the A1?

I’ve attached the .3mf file for reference. I’d appreciate if someone from the Bambu team or the community could help clarify what might be happening. I’m also concerned whether this kind of event could damage the printhead or mechanical parts if not caught in time.

Thanks in advance! :+1:
A1-filament-hub-dust-cap-mirrored(2).3mf (800,1,KB)

2

Sorry, I don’t have access to an A1 printer to test your file.

  • Are you completely sure you’re selecting the correct Bambu printer and not, for example, the Mini or another version ?

  • Some files found online may contain flawed meshes, but you can sometimes repair them.

  • What happens if you slice a primitive cude ?

  • Have you tried performing a factory reset ?

  • Last attempt to downgrade the firmware, assuming the hardware is functioning properly.

.
I hope this helps you get back up and running.

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3

@3DTech Thank you for your reply!

  1. Yes, I made sure the correct printer (Bambu Lab A1) was selected when sending the file.
  2. The file used was downloaded directly from MakerWorld, and it is compatible and free of mesh issues.
  3. I haven’t tested slicing a primitive cube yet, but I’ve been printing many other models without issues — this problem doesn’t occur consistently.
  4. I’ll try doing a factory reset and will update here with the results.
  5. As a last resort, I’ll consider testing a firmware downgrade if the hardware continues to behave normally.

Thanks again for the support!

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4

You’re welcome!

If your other files are printing correctly, it might be a good idea to reach out to the creator on MakerWorld and ask them to inspect the mesh sometimes even a tiny hole can cause issues with 3D printing. Additionally, take a look at the travel moves in your slicer preview, as might help pinpoint the issue with that particular G-code file.

Let’s hope it’s just the file and not your printer.

Have a good one :v:

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5

I also have problems, but with the bed calibration. for some reason it fails.

I had started a print but it didn’t start, it was probably due to filament that got stuck on the nozzle.

I removed the filament and restarted the print job. The printer then started the calibration and also started printing the first layer. Then it went into the print bed and even damaged the heating bed. It only failed because it said in the app that it couldn’t cut the filament. No filament change was planned. This has now happened to me for the 2nd time. I now have over €100 in repair costs due to failed calibration. After I started the print job a 3rd time, the calibration was successful and it printed. I don’t know why this is happening. I suspect it is because if the printer had a calibration error and you restart the print job this happens.

1 Like