• 23 parts
  • Checked September 2026

Parts of a 3D Printer

A desktop filament printer from spool to print surface, with its print head drawn larger.

Parts of a 3D Printer

Name Date

Tap any part to read, rename or leave it out

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23
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Write the name of each numbered part.Answer key

  1. Filament spool
  2. Filament
  3. Nozzle
  4. Heated bed
  5. Extruder
  6. Display
  7. Frame (base)
  8. Print surface
  9. Spool holder
  10. Gantry
  11. Hotend
  12. Print fan
  13. Control knob
  14. Memory card slot
  15. Power supply
  16. Filament sensor
  17. X-axis
  18. Y-axis
  19. Belt
  20. Lead screw (threaded rod)
  21. X-axis motor
  22. Z-axis motor
  23. Extruder motor

Drawn for this site by script, 2026-09-24. Licence: own work.

Each numbered ring is a button. Use the arrow keys to move between them and Enter to choose. Names are read out in Study, and once a part is answered.

Next step Next machine: a record player

All 23 parts on the diagram

Show the list

Start here: 8 main parts 8

  1. Filament spool Holds the plastic line, wound like thread on a reel.
  2. Filament The plastic the printer melts; many printers take 1.75 mm.
  3. Nozzle The melted plastic comes out of its tiny hole.
  4. Heated bed A warm plate under the print surface; it can pass 100 °C.
  5. Extruder Its gear pulls filament in and pushes it to the hotend.
  6. Display Shows temperatures and menus; you pick a file here.
  7. Frame (base) The rigid base everything else is bolted to.
  8. Print surface The print sticks to it, then pops off when it cools.

The whole printer 12

  1. Spool holder Lets the spool turn freely as filament is drawn off.
  2. Gantry Carries the X-axis and the print head above the bed.
  3. Control knob Turn it to move through the menu, press it to choose.
  4. Memory card slot Takes the card carrying the file to print.
  5. Power supply Turns mains power into the low voltage the printer runs on.
  6. Filament sensor Pauses the print if the filament runs out.
  7. X-axis Moves the print head left and right.
  8. Y-axis On this kind of printer it slides the bed back and forth.
  9. Belt A toothed belt pulls the head along its axis.
  10. Lead screw (threaded rod) Turns to raise the X-axis one layer at a time.
  11. X-axis motor A stepper motor that drives the X belt.
  12. Z-axis motor A stepper motor that turns the lead screw.

The print head, close up 3

  1. Hotend Melts the filament; the nozzle reaches about 210 to 300 °C.
  2. Print fan Cools the plastic as each new line is laid.
  3. Extruder motor A stepper motor that turns the extruder gear.

How this list was compiled: Read 2026-09-24. (1) Wikipedia, Fused filament fabrication, https://en.wikipedia.org/wiki/Fused_filament_fabrication : filament on a spool, the extruder with its cold end and hot end, the nozzle, stepper motors, a gantry over a flat bed, toothed belts for X and Y and a leadscrew for Z. (2) A kit printer maker's user handbook, https://www.prusa3d.com/downloads/manual/prusa3d_manual_mk3s_en.pdf : its printer description names the filament spool, spool holder, Z-axis, power supply, X-axis, Z stepper, heatbed with spring steel sheet, LCD knob, threaded rod, printer frame, extruder stepper, X stepper, Y-axis, LCD panel and SD card slot; also the print fan, hotend, nozzle, filament sensor, belts, 1.75 mm filament, a nozzle at 210 to 300 °C and a heatbed over 100 °C. (3) A bed-slinger maker's user manual, https://cdn.creality.com/ow/official/1e3cee7e-f5bd-46f8-945d-6144b2285385.pdf : base frame, gantry frame, spool, spool holder, display, knob, memory card slot, printing platform, heated bed, X-, Y- and Z-axis motors, extrusion motor, hotend, nozzle, front print fan, filament sensor, belt tension knobs, power supply switch. Licence: own work

The drawing: Drawn for this site by script, 2026-09-24. Licence: own work

How it works

A filament 3D printer melts a thin plastic line and lays it down one layer at a time. This one is the common kind whose bed slides back and forth under the head.

Read the full guide

From spool to nozzle

Filament comes off the spool, through the filament sensor, into the extruder. The extruder's motor turns a gear that pushes it down into the hotend, where it melts. It leaves through the nozzle, and the print fan cools each line as it lands.

Three axes

A belt pulls the head along the X-axis, side to side. The bed rides the Y-axis, front to back. After each layer the Z-axis motor turns the lead screw and lifts the whole X-axis a little higher.

  • The heated bed and nozzle stay hot after a print; let them cool before you touch them.

Questions and answers

What is the difference between the extruder and the hotend?

The extruder is the cold end: a motor and gear that grip the filament and push it. The hotend is the heated part below it that melts the plastic, with the nozzle at its tip.

What is the print surface on a 3D printer?

A thin sheet laid on the heated bed. The print is built on it, never straight on the bed. On some sheets the print comes off by itself once the sheet has cooled.

What does the lead screw do on a 3D printer?

It raises the X-axis, and with it the print head, one layer height at a time. A motor at its foot turns it, and the threads carry the beam up.

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