Printing PA-CF on a Bambu Lab printer without clogging

To print PA-CF (carbon-fiber nylon) on a Bambu Lab printer without clogging, fit a hardened steel nozzle (0.6 mm by preference, never 0.2 mm) and dry the spool at 80 °C for 8 to 12 hours. Keep it sealed below 20% humidity while it prints, stay at Bambu Studio’s 8 mm³/s flow limit, and clear carbon fiber out of the nozzle with a cold pull at least once a month. If the nozzle is already blocked, the unclog steps start with it heated to 280 °C.

Figures come from Bambu Lab’s wiki, filament data sheets and Bambu Studio presets as published on October 24, 2026.

Why does PA-CF clog on Bambu Lab printers?

PA-CF clogs when carbon fibers collect inside the nozzle. Bambu Lab says fiber filaments such as PAHT-CF tend to leave this residue. A 0.2 mm or worn nozzle, wet filament, printing faster than the filament melts and frequent short jobs make it worse. A hot chamber can also soften filament above the nozzle (heat creep).

Rows follow the filament’s path, from the spool to the nozzle tip.

Nozzle. Bambu Lab’s filament guide rates a 0.6 mm hardened steel nozzle “Recommended” for PA-CF, PA6-CF and PAHT-CF, 0.4 and 0.8 mm “Compatible” and 0.2 mm “Not Compatible”. Nozzles above 0.4 mm “tend to clog a lot less”, Bambu says, because larger particles pass through. Bambu Studio’s nylon CF presets ask for 40 HRC (Rockwell C hardness); the software rates stainless steel at 20 and hardened steel at 55. In Bambu’s P1S upgrade guide, 10 hours of PETG-CF visibly enlarged a stainless nozzle’s orifice, and signs of nozzle wear shows how to check yours.

Heat creep. Bambu Lab’s advice to open the door or lid applies to filaments that soften below 80 °C, such as PLA and PETG. For PA-CF its tables answer “NO” to removing the glass lid, and it wants chamber heat for these materials “to suppress warping and layer separation”. The table’s 60 and 58 °C chamber ceilings sit 10 degrees below each filament’s glass transition temperature, the point where it starts to soften: 70 °C for PAHT-CF and 68 °C for PA6-CF on Bambu’s data sheets.

The P1S and X1 Carbon have no chamber heater, so their chamber warms only from the bed. On the X1E, Bambu Studio’s PAHT-CF and PA6-CF presets set the chamber to 60 °C, 2 °C above the PA6-CF ceiling.

How do you print PA-CF on a Bambu Lab printer without clogging?

Fit a 0.6 or 0.4 mm hardened steel nozzle, dry the spool at 80 °C for 8 to 12 hours and feed it from a sealed box. Clean the nozzle at 280 °C first, then slice with Bambu Studio’s preset and keep its 8 mm³/s limit. Shut the door and lid, and cold pull monthly.

How to print PA-CF on a Bambu Lab printer without clogging

1. Fit a hardened steel nozzle. Use 0.6 mm first, 0.4 mm for detail, never 0.2 mm. On a P1S, add hardened extruder gears. Then set the nozzle type and size on the printer’s screen. Fitting a hardened steel nozzle covers the swap.
2. Dry the spool. Use 80 °C for 8 to 12 hours in a forced-air oven, or 12 hours on a 90 to 100 °C bed. Methods are in drying filament for Bambu Lab printers.
3. Feed it dry. Print from a sealed box with desiccant, below 20% relative humidity (RH). Bambu says dried filament in a room at about 55% RH can absorb enough moisture to hurt print quality within 2 to 12 hours. Bambu PAHT-CF can run from an AMS (Bambu’s Automatic Material System), AMS 2 Pro or AMS HT, not an AMS lite; other PA-CF goes on the external spool holder. See AMS-compatible filaments.
4. Clean the nozzle. Before fiber-filled prints, Bambu’s filament guide says to heat the nozzle to 280 °C and clear residue inside it with “an Allen key and a needle”.
5. Use the system preset. Bambu Studio’s P1S and X1 Carbon presets print PAHT-CF at 290 °C and PA6-CF at 275 °C, capped at 8 mm³/s on the standard hotend for every nozzle size. Keep the cap and stay under 100 mm/s; on a 0.4 mm nozzle, use 0.15 to 0.3 mm layers. Leave retraction at the printer preset: 0.8 mm on a P1S 0.4 mm nozzle and 1.4 mm on 0.6 mm, at 30 mm/s. Both sit within the data sheets’ 0.8 to 1.4 mm at 20 to 40 mm/s. Full settings are in nylon settings for Bambu Lab printers.
6. Close the printer. Shut the door and keep the glass lid on. In a cold room, Bambu suggests heating the bed to its maximum for 15 minutes before a P1S or X1 Carbon print. Crack the door open only if the extruder jams.
7. Combine short jobs. Fewer heat-up and cool-down cycles leave less residue in the nozzle.
8. Cold pull monthly. Bambu recommends a cold pull (pulling filament from a cooled nozzle to drag residue out) at least once a month and when changing filament type. Before switching to a cooler filament, unload at 250 to 300 °C, load the new one and keep extruding as the nozzle cools to 220 to 240 °C.

Bambu Lab asks for a ventilated room or air filtration when printing these filaments, and cut-resistant gloves and goggles when handling them or sanding parts, because the filament can carry “hard, microscopic barbs”.

How do you unclog a Bambu Lab nozzle after printing PA-CF?

Heat the nozzle to 280 °C and clear the tip with the supplied pin. If that fails, purge with PLA and finish with a cold pull at 100 °C. A clog shows as thin, gappy walls or no extrusion, and partly clogged filament extruded from the screen curls instead of dropping straight. Bambu Lab’s procedure for the X1 and P1 series:

1. Heat the nozzle. Under Settings > Temperature/Axis, set the hotend to 280 °C, Bambu’s temperature for cleaning fiber-filled nozzles. Lower the bed halfway with the -10 button.
2. Pin the tip. Wearing heat-resistant gloves and keeping your face away, work the supplied pin in and out of the tip a few times without pushing it deep. Bambu warns that trapped pressure “can cause molten filament to spray out suddenly”. Skip this on a 0.2 mm nozzle.
3. Check the flow. Extrude from the screen. A straight strand means the tip is clear; if it still curls or nothing comes out, move to step 4.
4. Purge with PLA. Remove the toolhead cover, loosen the screws beside the PTFE support and pull the tube out. At 250 to 300 °C, unload the PA-CF and push PLA into the extruder until clean PLA comes out, then let the nozzle cool to 220 °C.
5. Cold pull. Set the hotend to 100 °C. When it gets there, retract and pull gently on the filament. Repeat until the end comes out clean.
6. Refit and test. Push the PTFE tube back into the filament sensor, raise its support fully, tighten it and refit the cover. Replace a nozzle that still will not clear.

For the A1 series, Bambu’s guide differs: take the hotend out at 100 °C wearing an oven glove and pull filament from its entrance with pliers. Then refit the hotend, load fresh filament at 220 °C and cold pull at 100 °C. The pin method there needs a nozzle of 0.4 mm or larger.

Which nylon CF filaments does Bambu Lab make?

Bambu Lab sells PAHT-CF (carbon fiber in PA12 and other long-chain nylons) and PA6-CF (carbon fiber in nylon 6). PAHT-CF replaced the discontinued Bambu PA-CF. For clogging, the differences are moisture and the AMS: PA6-CF absorbs more water and cannot feed through any AMS. Filaments are in alphabetical order.

Can the Bambu Lab P1S print PA6-CF?

Yes, with a hardened steel nozzle. Bambu Lab’s PA6-CF guide calls for an enclosed printer and excludes only the P1P and A1 series. The PA6-CF store page marks stainless steel nozzles (the P1S’s stock nozzle) “NOT Recommended” and 0.2 mm nozzles “NOT Compatible”. Bambu Lab also recommends hardened extruder gears on the P1S.

The P1S spec sheet describes the printer as shipped and rates PA “Capable” and carbon- or glass-fiber filament “Not Recommended”. Bambu Studio has Bambu PA6-CF presets for the P1S’s 0.4, 0.6 and 0.8 mm nozzles, printing at 275 °C on a 100 °C bed (the P1S maximum). The same nozzle and gear upgrade covers PAHT-CF.

Can the Bambu Lab A1 or X1 Carbon print nylon CF?

The Bambu Lab X1 Carbon prints nylon CF as delivered. It ships with a hardened steel nozzle and extruder gears, and its spec sheet rates PA and fiber-filled filament “Ideal”.

The Bambu Lab A1 is outside Bambu Lab’s guidance. Its spec sheet rates PA and carbon- or glass-fiber filament “Not Recommended”. The filament guide gives open-frame printers the same rating for PA-CF, PA6-CF and PAHT-CF, and the PAHT-CF store page calls the filament “unsuitable for use with open-frame printers”.

Bambu Studio still ships PAHT-CF and PA6-CF presets for the A1. Its extruder gears are hardened steel, but its stock nozzle is stainless, so an owner who tries nylon CF anyway needs Bambu Lab’s hardened steel hotend for the A1 first. Fitting a hardened steel nozzle covers the A1 swap.