Which nozzle do you need: size, brass or hardened steel?

First: does it fit your printer?

No nozzle fits every printer. Each brand, and sometimes each series, has its own system.

• Separate threaded nozzles, like Creality's nozzle kit and the E3D Nextruder nozzle for Prusa. You unscrew the old one and screw in the new one.
• Complete hotends, where you swap the nozzle together with the heater block. Bambu Lab works this way, with its own hotend per series, like the 0.4 mm hardened steel hotend for the A1 series. The hotends for the Snapmaker U1 and Flashforge's quick swap nozzles are made per printer too.

Check the product name for which printer or hotend a nozzle is meant for, and your printer's manual for which type it uses. Some nozzles are also made for a different filament size, like 2.85 mm instead of 1.75 mm.

The diameter: 0.2 to 0.8 mm

The diameter is the size of the hole. Almost every printer ships with 0.4 mm.

• 0.2 and 0.25 mm: thinner lines for small figures, fine text and small parts. Printing takes much longer. An example is the Micro Swiss 0.2 mm.
• 0.4 mm: the standard, a good balance between detail and speed.
• 0.6 mm: thicker lines, so faster printing and sturdier walls, with a little less detail. Handy for practical parts and for filled filament, like the E3D Diamondback 0.6 mm for the P1 series.
• 0.8 mm: faster still, for large objects where fine detail does not matter, like the Bambu Lab 0.8 mm hotend for the A1 series.

When you change nozzles, set the new diameter in your slicer. Programs like Bambu Studio and PrusaSlicer have separate profiles per nozzle size. With a larger nozzle you also choose a larger layer height.

The material: brass, hardened steel or diamond

Prusa writes that brass conducts heat very well and is tough enough for most common filaments. For PLA, PETG, ABS, ASA and TPU a brass nozzle is fine.

Filament with carbon fibre or glass fibre is abrasive. According to Prusa it wears a brass nozzle too quickly, which is why wear-resistant nozzles exist. A common kind is hardened steel, like the Elegoo hardened steel nozzle set and the Bambu Lab hotend for the P1 series. Other makers use a coating or a hard tip. Micro Swiss calls some of its nozzles coated and wear resistant, and E3D's Diamondback hotends have a polycrystalline diamond tip from the maker DiamondBack, like the Diamondback for the X1 Carbon.

If you print filled filament now and then and regular PLA the rest of the time, you can simply leave a wear-resistant nozzle in the printer. You notice a worn nozzle by thinner or uneven lines and prints that are no longer as clean.

Regular or high flow

A high flow nozzle or hotend can melt more filament per second. That helps on fast printers, which otherwise have to wait for the filament to heat up. Makers put it in the name, like the E3D Obxidian High Flow for the Bambu Lab X1 and P1 and the Micro Swiss FlowTech with CHT for the P1S. CHT is a Bondtech design that splits the filament into three streams inside the nozzle, so it heats up faster.

If you do not print at top speeds, you do not need high flow. A regular nozzle from the manufacturer works just as well then.

Changing nozzles and keeping spares

A nozzle wears out over time. It is handy to keep one or two spares, also to switch between sizes. A set with several sizes, like the Elegoo set with 0.4, 0.6 and 0.8 mm, makes that easy. Follow your printer's manual when you change it: with many systems the nozzle has to be hot to loosen it, and with a complete hotend you take care with the cables.

Read more about which filament suits which nozzle in our guide choosing filament.