Hotend vs nozzle: what's the difference?

A hotend is not a nozzle: the nozzle is one part of it. Prusa Research defines the hotend as the nozzle, heat break, heatsink, heater block, heater cartridge and thermistor cartridge, plus a collet clip and PTFE (Teflon) tube. Replace the nozzle when it is worn, clogged or the wrong size, and the heater or sensor when the hotend stops heating or reads the wrong temperature.

Is a hotend the same as a nozzle?

No. A hotend is the assembly that melts filament; the nozzle is only its tip, the part that sets line width and wears out. Around it sit a heater block, heater, temperature sensor, heat break and a heatsink with its fan. Bambu Lab uses both words for one part, because it sells nozzles only as whole hotends.

On E3D V6- and MK8-style hotends, the nozzle is a separate part that screws into the heater block and is sold on its own. E3D sells V6 nozzles apart from its V6 hotend kit, and Micro Swiss lists its M6x1.0 MK8 nozzle as fitting the Creality Ender 3 family.

Bambu Lab hotend vs nozzle

On Bambu Lab printers there is no loose nozzle tip to buy. Bambu Lab’s nozzle guide opens with “Nozzle, also called the hotend”. Its X1 guide says the hotends “are designed as a single unit, incorporating the heatsink, throat, heater block, and nozzle.” The smallest replacement part is that unit, listed in the box as “Hotend with Nozzle” or “Hotend”.

What are the parts of a 3D printer hotend?

A 3D printer hotend has a nozzle, a heater block that holds it, a heater and a temperature sensor (thermistor or PT1000) in that block, a heat break that stops heat climbing, and a heatsink cooled by its own fan. Many add a silicone sock. PTFE-lined designs also run a plastic tube down to the nozzle.

The table lists the parts from the tip up.

Designs bundle these differently. E3D’s V6 All-Metal HotEnd kit ships every part separately, while E3D’s Revo combines heater and thermistor in one “HeaterCore”. Choosing a hotend for engineering filaments covers all-metal vs PTFE-lined and how each part sets the temperature limit.

If a replacement heater or sensor differs from the original, such as another thermistor type or a PT1000, set the new type in the firmware before you heat the hotend. Thermal-runaway protection depends on a correct reading; Klipper heater verification explains how it works.

What is the difference between a hotend and a complete hotend?

On the Bambu Lab X1 Carbon, P1P and P1S, a hotend is the metal unit of nozzle, heater block, heat break and heatsink. A complete hotend is that unit with the ceramic heater, thermistor, hotend fan, silicone sock and retaining clip fitted. Buy the hotend for a worn nozzle, the complete hotend when the heater or thermistor has failed.

Both are options under Type on the “Bambu Hotend - X1C” and “Bambu Hotend - P1 Series” store listings. Per those listings and Bambu Lab’s wiki:

Bambu Lab calls the plain hotend “cheaper to replace, as the electronics can be re-used”. The complete hotend is “a bit more expensive” but fits in one step: unplug three connectors and remove two screws. Moving parts across means pulling the heater and thermistor out of old thermal grease. If it has hardened, Bambu Lab says not to force them: let alcohol soften the grease for about 5 minutes.

The complete hotends are series-specific. The X1 Series version fits the X1 and X1 Carbon, not the X1E, and the P1 Series version fits the P1P and P1S. Bambu Lab notes the heater and thermistor connectors may differ between the two.

Other makers use “complete” loosely. E3D’s High Flow ObXiDian 500 Complete HotEnd for Bambu Lab printers lists only “1 x Assembled” hotend in the box, so read the contents list, not the product name.

Which Bambu Lab part to buy for which fault

The A1, A2L, H2, P2S and X2D printers have no complete hotend. The heater and thermistor stay on the toolhead in a “hotend heating assembly” that the hotend latches into, a design Bambu Lab says enables “easy separation of the thermal and electronic components of the hotend.” Printers are listed alphabetically.

Bambu Lab’s reasons to replace a heating assembly: the hotend no longer heats or heats abnormally, the latch no longer holds the hotend, or the assembly is encased in plastic after a failed print. The H2D’s left and right assemblies “are not interchangeable”, and A1 and H2D assemblies are not compatible.

Check the repair before printing: Bambu Lab’s guides heat the hotend to 100 °C (A1) or 220 °C (H2D) and confirm the reading rises. If the new hotend is a different size or material, enter it on the printer’s screen: Bambu Studio’s nozzle field is display-only.

Which hotends have the nozzle and heat break in one part?

Bambu Lab hotends, the E3D Revo and Prusa Research’s Prusa Nozzle join the nozzle and heat break in one part, so the nozzle changes cold. On E3D V6- and MK8-style hotends they are separate: the nozzle screws into the heater block against the heat break and is tightened hot.

• Bambu Lab. On the X1 Carbon and P1 series, “the nozzle is integrated into the heatblock and connected to the heatsink via a thin metal tube”, and the hotend “can be installed when cold.”
• E3D Revo. The nozzle and HeatBreak “are integrated into a single unit”, unscrewed “with your fingers at room temperature.”
• Prusa Nozzle. On Prusa Research’s Nextruder printers (MK4, MK3.9, XL and CORE One families), it “integrates the heatbreak directly into the nozzle, eliminating the need to preheat the hotend for installation.”
• E3D V6 and MK8 style. For a brass V6 nozzle, E3D says to heat the hotend to 285 °C and tighten to 2 Nm.

The nozzles do not cross over. A Revo hot side is always “a HeaterCore and Revo Nozzle”, and Prusa Research offers a Nextruder V6 Nozzle Adapter so its printers can take E3D V6 nozzles.

What is the hot end vs the cold end?

“Cold end” has two meanings. The open-source RepRap project uses “cold end” for the extruder drive, which “forces the raw material … into the hot end”; the hot end “melts the filament.” E3D uses the terms inside the hotend: the heat break splits it into a heated “hot side” and a cooled “cold side” that is “normally attached to the printer.”

Bambu Lab uses the second meaning: its nozzle guide calls the fan-cooled top of the hotend the “Cold End”, which “keeps the filament solid until it enters the melting zone.” So check which one a parts listing means: an extruder drive and a heatsink are different purchases.

Where the drive sits depends on the printer. On the Original Prusa MINI the extruder motor is fixed to the frame and pushes filament through a PTFE tube to the print head. On a direct-drive printer it rides on the toolhead, which is what the Ender 3 direct drive conversion changes.

What is the difference between a hotend and a toolhead?

The toolhead is everything on the moving carriage; the hotend is one module in it. Prusa Research lists its i3 print head as “a hotend w/nozzle, hobbed pulley, idler, a nozzle fan (print fan), hotend fan, P.I.N.D.A.-probe, filament sensor, and extruder motor.” Bambu Lab calls the hotend “the toolhead module’s core component.”

Names vary by maker. Prusa Research calls the whole i3 print head the “extruder”, but on the MINI uses “extruder” for the drive motor alone. A worn nozzle or a failed heater never needs a new toolhead.