Nozzles screw into the hot end of a 3D printer extruder, acting as the exit point for the melted thermoplastic filament.
3D printer nozzles are made from solid metal, featuring a tiny nozzle opening. The nozzle opening size (bore size) defines the thickness of the melted filament on exit, with typical nozzle sizes ranging from 0.1-0.4mm.
All 3D printer nozzles are made from metal, and they can be single-piece (common) or assembled (uncommon). Today, most 3D printers ship with a brass nozzle. You can upgrade the nozzle at any time, providing it is user-replaceable.
The most common 3D printer nozzle material is brass, chosen because it operates across a wide temperature gamut with solid longevity. Brass is cheap, readily available and suitable for printing ABS and PLA, the two most common filaments.
However, brass is relatively soft as far as metals go, so it isn’t suitable for abrasive filaments like composites and metals.
For abrasive materials and composites, stainless steel nozzles are preferred. Stainless steel lasts at least five times longer than brass because it is harder.
The downside to stainless steel is poor thermal conductivity, so it has inconsistent performance at low temperatures and is best-suited to high temperatures. Typically, these nozzles happily print at temperatures up to 500°C.
Hardened steel nozzles last even longer than stainless steel nozzles. Stainless steel cannot be hardened through heat treatment, but regular steel can, so hardened steel is harder and more durable for printing metals and abrasives.
Hardened steel has the lowest thermal conductivity, so it takes longer to heat up and is very inconsistent at lower temperatures, so it is only suited to high-temp materials.
Assembled nozzles are more expensive but address the concerns of hardened nozzles by combining the materials with softer materials with better thermal conductivity. They are made by combining a screw section with a nozzle end section.
An assembled nozzle might have a hardened steel tip and a brass bulk material, thus creating a nozzle with good heat transfer and high-temp capabilities.
The bore diameter of a 3D printer nozzle defines the thickness of the melted extruded thermoplastic. Today’s standard nozzle is the 0.4mm nozzle, but larger and smaller bore sizes are available for different applications.
Larger bores mean more material is extruded, speeding up print time, but sacrificing detail in the process. What one hand giveth, the other takes away.
Higher precision is available with smaller bore sizes. Most people benefit from having a few nozzles to increase 3D printer use cases.