The filament cutter gets stuck («The cutter is stuck») or fails to cut

Symptom

When unloading or changing colour, the printer stops with «The cutter is stuck» (for example 0300-800B, 0700-8002 with the AMS or 1200-8002 with the AMS lite) or with «Failed to cut the filament» (0700-8001). Sometimes the cutter lever stays pressed into the toolhead.

Likely causes, from most to least likely

1. The lever caught for a moment and sprang back on its own: it happens now and then with support or silk filaments.
2. False alarm from the Hall sensor that watches the lever: dirt on the magnet or sensor, a damaged sensor or cable, or a loose 10-pin connector (X1 and P1).
3. Clogged hotend: filament pressure between the extruder and the hotend traps the blade and stops it springing back.
4. Too much friction between the sides of the blade and the extruder, or the toolhead fan cable caught on the lever.
5. Dull or badly fitted blade: it cuts poorly and causes problems when the filament is pulled back to the AMS.

Checks to tell which one it is

• Check whether the lever is really stuck in the toolhead or back in place: the printer warns if it does not detect the lever returning within two minutes.
• Press «Retry» once: if the alert does not return, it was a one-off catch.
• Unload the filament and press the lever by hand with no filament: if it still sticks, the blade has too much friction.
• Look at the filament tip after unloading: if it is not cut straight and clean, the blade is worn.

Before you start

Before taking anything apart, cleaning or adjusting it, switch the printer off and unplug it, unless a step says otherwise, and do not touch the nozzle, the heater block or the bed until they have cooled down. If in any doubt about electricity, heat or moving parts, stop and ask a professional.

Step-by-step fix

1. If the lever is back in place

   Press «Retry». If it happens again, switch the printer off, clean the lever magnet area and the Hall sensor area and, on the X1 and P1, reseat the 10-pin connector (remove the silicone with tweezers first; it sometimes needs reseating several times).

   Check: The alert does not come back when cutting.

   If that does not fix it: If it continues, the extruder Hall sensor or its cable may be faulty: contact Bambu Lab support.

2. If the lever is really stuck

   Check whether the hotend is clogged and, if it is, clear it with the procedure for your model before going any further: it is the most common cause.

   Check: With a clean hotend, the lever springs back after cutting.

   If that does not fix it: Test the lever with no filament (next step).

3. Check friction and the fan cable

   With no filament, press the lever several times. If it sticks, remove the blade using the Bambu Lab guide: Bambu Lab says the sides can be trimmed slightly to reduce friction, but if you are unsure it is simpler to replace it. Route the toolhead fan cable so it cannot touch the lever.

   Check: The lever springs back when released.

   If that does not fix it: Replace the blade (next step).

4. Replace the blade (X1 and P1)

   Switch the printer off. Remove the toolhead front cover, keep the lever pressed while removing its screw with the flat end of the hex key, take out the old blade, fit the new one by aligning its tabs and tighten the screw; release the lever slowly. Careful: the blade is sharp.

   Check: After one load and one unload, the filament tip is cut straight and clean.

   If that does not fix it: If the screw is damaged, replace the whole lever, which comes with a new screw, or contact Bambu Lab support.

5. On the A1 and A1 mini

   If the cutter misbehaves, refit it following the A1 series cutter replacement guide and, if the blade is worn, replace it: spares come in the box. Do not overtighten the screw or you may damage the plastic thread.

   Check: The cut is clean and there are no layer shifts when the toolhead cuts.

   If that does not fix it: Contact Bambu Lab support.

Prevention

• On the X1 and P1, check the blade every 3-5 spools of PLA, PETG, ABS or PC and every 1-2 spools of abrasive filament.
• On the A1, Bambu Lab advises replacing the blade every 10-15 spools: after about 5,000-7,000 cuts it can be dull even if it does not look deformed.
• Avoid hotend clogs: they are what jams the blade most often.

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Printers it applies to

Bambu Lab X1 Carbon, X1, X1E, P1S, P1P, A1 and A1 mini.

Official sources

This guide summarises the official documentation linked here:

• The printer shows that the cutter is stuck · Bambu Lab
• Replace the Filament Cutter Replacement - X1 & P1 Series · Bambu Lab
• Filament Cutter Replacement Guide · Bambu Lab
• Bambu Lab X1 Maintenance Recommendation · Bambu Lab
• Error Code · Bambu Lab