Even with highly automated printers like the Bambu Lab series, failures can and do happen. The difference is that Bambu’s smart sensors, closed-loop control, and slicer integration often prevent small issues from turning into catastrophic failures. Still, every user eventually faces a spaghetti monster, layer shift, or adhesion problem.
This post breaks down the most common failure types on Bambu Lab printers, why they happen, and how to fix them.
1. First Layer Adhesion Failures
Symptoms: Warping corners, prints peeling off mid-job, “dragged” lines in the first layer.
Causes:
- Bed not clean (oils or dust).
- Incorrect Z-offset.
- Wrong bed temperature or surface for the filament.
Fixes:
- Clean bed with isopropyl alcohol (and mild soap occasionally).
- Use the built-in first-layer calibration in Bambu Studio.
- Match surface to filament: textured PEI for PLA/PETG, smooth sheet or glue stick for ABS/Nylon.
2. Stringing and Oozing
Symptoms: Hair-like strands between parts, blobs on travel moves.
Causes:
- Retraction settings not tuned.
- High printing temperature.
- Moist filament (especially PETG, TPU, Nylon).
Fixes:
- Run the retraction calibration in Bambu Studio.
- Lower nozzle temperature slightly.
- Dry filament in a dryer or airtight container.
3. Under-Extrusion
Symptoms: Gaps between lines, weak infill, missing layers.
Causes:
- Partial nozzle clog.
- Filament grinding in extruder.
- Incorrect flow rate calibration.
Fixes:
- Clean or replace nozzle.
- Check extruder gears for debris.
- Run flow calibration in Bambu Studio.
4. AMS Feeding Problems
Symptoms: Filament doesn’t load/unload properly, mid-print filament errors, AMS jams.
Causes:
- Brittle filaments breaking in PTFE tube.
- Flexible or abrasive filaments not AMS-compatible.
- Moist filament sticking in spool.
Fixes:
- Reserve AMS for PLA, PETG, and non-abrasive filaments.
- Use manual loading for flexibles and composites.
- Store filament dry and check spool winding.
5. Layer Shifts
Symptoms: Model suddenly misaligned partway up, “stepped” layers.
Causes:
- Loose belts or pulley screws.
- Print head obstruction (colliding with print).
- Unstable surface or external bump during printing.
Fixes:
- Check belt tension in maintenance menu.
- Inspect pulleys and tighten if needed.
- Ensure stable placement of printer.
6. Spaghetti Failures
Symptoms: Printer extruding in mid-air, tangled string mess.
Causes:
- Part detached from bed mid-print.
- Under-extrusion leading to weak layers.
- AMS load error mid-print.
Fixes:
- Improve first layer adhesion.
- Run filament flow checks.
- Enable spaghetti detection in printer settings (AI camera can pause the print when detected).
Proactive Maintenance to Reduce Failures
- Clean bed weekly with IPA.
- Inspect nozzle monthly, especially after abrasive filaments.
- Dry filament regularly, particularly hygroscopic materials like Nylon and PETG.
- Update firmware and slicer to ensure you benefit from Bambu’s ongoing tuning.
Final Thoughts
Failures are part of 3D printing, but with Bambu Lab machines, most issues come down to material handling, bed prep, or nozzle wear. With consistent maintenance and smart use of built-in calibration tools, failure rates drop dramatically—making Bambu printers a strong choice for both hobbyists and production farms.
Zeltar Design 
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