Sooner or later every 3D printer needs a new nozzle. Maybe it clogged, maybe it wore out, or maybe you want a finer nozzle for small details. The good news: on most modern printers it takes well under an hour. This guide covers when to change it, which nozzle to choose, and the steps for two popular printers.
About this guide: the steps are summarized from the official manufacturer guides, checked in October 2026. Always keep the official guide open while you work, it has photos of every step: Prusa Core One, Bambu Lab A1 series.
When should you change the nozzle?
- It is clogged and a cold pull or cleaning does not help.
- It is worn. Prints get stringy or the walls look uneven even with good settings. Abrasive filaments like carbon fiber, glass fiber and glow-in-the-dark wear out brass nozzles quickly.
- It is damaged, for example after a crash into a print.
- You want a different size for finer detail or faster prints.
Which nozzle should you choose?
| Nozzle | Good for |
|---|---|
| 0.2 mm | Tiny parts and very fine detail, like miniatures. Slow. |
| 0.4 mm | The standard size. A good balance of detail and speed. |
| 0.6 mm | Faster, stronger functional parts with a little less detail. |
| 0.8 mm | Big, fast prints like planters and large parts. |
| Hardened steel | Abrasive filaments such as carbon fiber, glass fiber and glow-in-the-dark. |
Before you start
- Unload the filament first.
- Let the printer cool down and turn it off. Both Prusa and Bambu Lab do their nozzle swaps on a cold, powered-off printer.
- Have the new nozzle or hotend ready, plus the tools listed below for your printer.
- After the swap, tell the printer which nozzle you installed. Otherwise it prints with the wrong settings.
Prusa Core One and Core One+
On the Core One series you take the hotend out of the print head and unscrew the nozzle from it. Prusa rates the job as easy. You need a 2.5 mm Allen key, the 13–16 mm wrench and the universal wrench that come with the printer.
- Unload the filament, remove the spool and use Preheat → Cooldown to let the printer cool to room temperature.
- Move the bed down at least 100 mm (Control → Move Axis → Move Z), then turn the printer off and unplug it.
- Remove the top cover by pushing out the nylon rivets, and lay a cloth on the bed so you don’t scratch it.
- Remove the left side cover of the Nextruder (one M3 screw, 2.5 mm Allen key).
- Disconnect the hotend heater and thermistor cables. Press the latch on each connector first, or you can damage it.
- Hold the hotend with one hand, loosen the two thumb screws a few turns with the other, and slide the hotend out.
- Remove the silicone sock. Hold the heater block with the 13–16 mm wrench and loosen the nozzle with the 7 mm cutout in the universal wrench.
- Screw the new nozzle in by hand until it touches the heater block, then tighten it gently while you hold the heater block. Prusa specifies 1.5 Nm, so don’t use force.
- Push the hotend fully back into the heatsink and tighten the thumb screws. The copper ring on the nozzle should not be visible when it is fully seated.
- Route and reconnect the cables, put the covers back on, and turn the printer on.
- If you changed size or type, set it under Settings → Hardware → Printhead. Then heat the nozzle above 200 °C to check that the temperature rises normally.
Prusa also describes a faster method with a printed jig. The full guide with photos is in the Prusa Knowledge Base.
Bambu Lab A1 and A1 mini
On the A1 series you swap the whole hotend, nozzle and all, without tools. Bambu Lab says it takes just a few minutes. Hotends come in 0.2, 0.4, 0.6 and 0.8 mm, plus a high-flow version.
- Turn the printer off and make sure the nozzle is cold.
- Press the filament lever on the right side of the print head to release and cut the filament.
- Pull the front cover off from the bottom right corner, and remove the silicone sock.
- Unlock the hotend buckle: push it to the right, then swing the left side out.
- Hold the heatsink and pull the hotend straight out.
- Insert the new hotend at a slight angle toward the back. Magnets help it into place. Press it flat against the heating assembly.
- Close the buckle, left side first and then the right. If it won’t close, the hotend is not seated flat.
- Put the silicone sock back on and click the front cover into place.
- Update the nozzle size and type on the printer under Settings → Maintenance → Nozzle. In recent Bambu Studio versions you can no longer change this in the software.
If old filament makes the hotend stick, Bambu Lab suggests warming it slightly and wearing heat-resistant gloves. Full guide: Bambu Lab Wiki.
Other printers
Every hotend is a little different. Some older designs, such as classic E3D V6-style hotends, are tightened while hot to seal properly. Always follow the manual for your exact printer, and never touch a hot nozzle or heater block.
Common mistakes
- Forgetting to tell the printer about the new nozzle size.
- Overtightening the nozzle, which can strip the threads or crack parts.
- Not seating the nozzle or hotend fully, which can cause leaks and clogs.
- Pulling cables without releasing the connector latches.
Frequently asked questions
How do I clear a clogged nozzle, and why does it keep clogging?
If some filament still comes out, Prusa recommends a cold pull. Its steps for PLA on MK3-series printers: heat the nozzle to 270 °C, push PLA through by hand until it flows, let the nozzle cool to room temperature, then heat it to 85 °C and pull the filament out in one steady motion. A clean pull shows the shape of the nozzle on the tip with no dark specks; repeat until you get one. Check your own printer’s guide first, because temperatures differ and Prusa says not to cold pull its Nozzle X.
If PLA keeps clogging, heat creep is a likely cause. Polymaker describes it as heat travelling up the heat break and softening the filament before it reaches the nozzle, which forms a plug. Its fixes are a clean hotend fan that runs whenever the hotend is hot, venting a hot enclosure, and shorter retractions on direct-drive extruders. Prusa says an old, heavily used nozzle may be better replaced than cleaned; see how to change a 3D printer nozzle.
Sources: Prusa Knowledge Base, Polymaker Wiki.
When should I switch from a 0.4 mm to a 0.6 mm nozzle?
Switch when you print large or functional parts and care more about print time and strength than fine detail. In Prusa’s tests, a 0.6 mm nozzle cut almost 9 hours from one large print, and 0.6 mm test parts absorbed up to 25.6% more impact energy than 0.4 mm parts. The cost is lower resolution on small details and text. Keep layer height at or below about 80% of the nozzle width, so around 0.48 mm on a 0.6 mm nozzle.
A 0.6 mm nozzle also clogs less with filled filaments, and Prusa says wood-filled and other large-particle composites need at least 0.6 mm. Owners on the Bambu Lab forum report smaller time savings on fast printers, where the hotend’s melting rate already limits a 0.4 mm nozzle. Remember to change the nozzle size in your slicer profile after the swap.
Sources: Prusa blog, Prusa Knowledge Base, Bambu Lab forum.