3D Printing Glossary: Every Term Explained, A to Z
Slicer, retraction, warping, infill… 3D printing has its own vocabulary. This glossary explains, in plain English, the terms you will meet in manuals, software and forums.
The ten terms to know first
| Term | In short |
|---|---|
| FDM | The most common home technology: a melted plastic strand is laid down layer by layer. |
| Resin | A liquid that hardens under UV light, for very detailed parts. |
| Filament | The plastic strand, sold on spools, that feeds the printer. |
| Slicer | Software that cuts a model into layers and prepares the print. |
| G-code | The instructions the printer follows. |
| Nozzle | The heated tip the melted plastic comes out of. |
| Build plate | The surface the object is built on. |
| Calibration | Setting the distance between nozzle and build plate. |
| Layer height | The thickness of each layer: thinner means more detail and longer prints. |
| Supports | Temporary structures that hold up overhanging parts. |
All terms, A to Z
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3MF
A modern 3D file format that can store several parts, colors and print settings in one file, unlike STL. Used by most current slicers and by MakerWorld.
A
ABS
A heat- and impact-resistant plastic (the one LEGO bricks are made of). It shrinks as it cools and gives off fumes: it needs a hot bed, ideally an enclosure and good ventilation.
Adhesion
How well the first layer sticks to the build plate. Poor adhesion is the most common cause of failed prints. A clean plate, correct Z offset and sometimes a brim help.
ASA
A plastic similar to ABS but resistant to UV light, which makes it a good choice for outdoor parts. Same need for an enclosure and ventilation.
Auto bed leveling
A sensor measures the build plate at many points, and the printer compensates for unevenness automatically. The most useful feature on a beginner printer.
B
Bed slinger
Nickname for a printer whose build plate moves back and forth (the Y axis), like many classic and budget models. Simple and affordable, but slower than a CoreXY at high speeds.
Bowden
A setup where the extruder motor sits on the frame and pushes filament through a long tube to the hotend. Lighter print head, but harder with flexible filament. Opposite of direct drive.
Bridging
Printing a horizontal span between two points with nothing underneath. Short bridges work without supports; long ones sag.
Brim
A thin, flat border printed around the base of an object to increase contact with the plate and prevent warping. Peeled off after printing.
Build plate (print bed)
The surface the object is printed on. Usually heated, and often a removable flexible steel sheet with a PEI coating.
Build volume
The largest object a printer can make, given as width × depth × height, for example 256 × 256 × 256 mm (about 10 × 10 × 10 in).
C
Calibration
Adjusting the printer so it prints accurately: mainly the nozzle-to-plate distance (leveling and Z offset), but also flow rate, temperature and vibration compensation. Recent printers do most of it automatically.
Clog
A blockage in the nozzle or hotend that stops or reduces the flow of plastic. Often caused by dust, wet or low-quality filament, or heat creeping up the hotend.
CoreXY
A motion system where the print head moves in X and Y on two belts while the plate only moves down. Faster and more compact than a bed slinger; used by many recent printers.
Curing
For resin prints: exposing the washed part to UV light so it reaches its final hardness.
D
Direct drive
The extruder sits right on the print head, just above the hotend. Better control of the filament, especially flexible TPU. Opposite of Bowden.
DLP
A resin printing technology where a projector cures a whole layer at once. Less common in home printers than MSLA.
E
Enclosure
A closed box around the printer that keeps heat in and drafts out. Needed for ABS and ASA; also reduces noise and contains some fumes. Not required for PLA.
Extruder
The motor and gears that grip the filament and push it into the hotend. Sometimes used loosely for the whole print head.
F
FDM / FFF
Fused Deposition Modeling (or Fused Filament Fabrication): melting a plastic filament and laying it down layer by layer. The most common technology for home printers.
Filament
The plastic strand (PLA, PETG, ABS…) that FDM printers use, usually 1.75 mm in diameter and sold on 1 kg spools. It absorbs moisture and should be stored dry.
First layer
The layer printed directly on the plate. It decides whether a print sticks and succeeds: it should be slightly squished, even and continuous.
G
G-code
The text file of instructions (moves, temperatures, speeds) that the slicer creates and the printer executes line by line.
H
Hotend
The heated part of the print head: heater, temperature sensor, heat break and nozzle. An all-metal hotend can reach higher temperatures for technical materials.
I
Infill
The internal pattern that fills a print, given as a percentage. 15–20 % is enough for most objects; higher values make parts stronger, heavier and slower to print.
Input shaping
A firmware feature that measures and cancels the printer’s vibrations, allowing higher speeds without ripples (“ringing”) on the surface.
IPA (isopropyl alcohol)
Used to clean the build plate and, for resin printing, to wash uncured resin off parts.
K
Klipper
An open-source printer firmware known for speed features like input shaping. Used on many fast printers and popular with tinkerers.
L
Layer height
The thickness of each printed layer, typically 0.1 to 0.3 mm on FDM printers. 0.2 mm is a good default; thinner layers look smoother but take longer.
Lithophane
A thin print whose varying thickness reveals a photo when light shines through it. A popular gift project.
M
MSLA
Masked stereolithography: an LCD screen masks a UV light source to cure a whole resin layer at once. Almost all home resin printers use it.
Multicolor unit
An add-on that holds several spools and switches between them automatically during a print (for example Bambu Lab’s AMS or Creality’s CFS). Each switch wastes some filament (purge).
N
Nozzle
The metal tip the melted plastic comes out of, usually 0.4 mm wide. Brass is standard; hardened steel is needed for abrasive filaments such as carbon-fiber blends.
Nylon (PA)
A very tough, slightly flexible engineering plastic. It absorbs moisture quickly and needs drying, high temperatures and usually an enclosure.
O
Overhang
A part of a model that sticks out over empty space. Up to about 45° prints fine; steeper overhangs need supports.
P
PEI
A coating on many build plates that holds prints well when hot and releases them when cool or when the flexible plate is bent.
Perimeters (walls)
The outer outlines of each layer. More walls make a part stronger, often more than extra infill.
PETG
A tough, slightly flexible plastic, related to water-bottle plastic. More heat- and impact-resistant than PLA, a bit more prone to stringing. A good second material.
PLA
The standard beginner filament: prints at low temperature, needs no enclosure, smells little and is stiff. It softens at around 55–60 °C (130–140 °F), so it doesn’t suit a hot car.
Purge
Plastic pushed out and discarded when changing filament or color, to clear the old material from the nozzle. Multicolor prints can waste a lot of filament this way.
R
Raft
A thick base of several layers printed under the object to improve adhesion on difficult shapes. Uses more material than a brim and leaves a rougher bottom.
Resin
A liquid photopolymer that hardens under UV light, used by MSLA, SLA and DLP printers. Very detailed results, but irritating to skin: wear gloves and ventilate.
Retraction
Pulling the filament back slightly before a travel move so plastic doesn’t ooze out. Too little causes stringing; too much can cause clogs.
S
Skirt
A line printed around the object, without touching it, to prime the nozzle and check the first layer before the real print starts.
SLA
Stereolithography: a laser traces each resin layer point by point. Often used loosely for all resin printing.
Slicer
Software that turns a 3D model into layers and G-code. Popular free slicers: Bambu Studio, PrusaSlicer, OrcaSlicer and UltiMaker Cura.
SLS
Selective Laser Sintering: a laser fuses plastic powder (usually nylon). Strong parts without supports; mostly used by professional services.
Spaghetti
The tangled mess you get when a print comes loose and the printer keeps extruding into the air. Some printers detect it with a camera and pause.
STL
The most common 3D model file format. It stores only the shape, not colors or settings. See also 3MF.
Stringing
Thin hairs of plastic between separate parts of a print. Usually fixed by lowering the temperature, adjusting retraction or drying the filament.
Supports
Temporary structures the slicer adds under overhangs. Removed after printing; they can leave marks on the surface.
T
TPU
A flexible, rubber-like filament for phone cases, gaskets and bumpers. Prints slowly and works best with a direct drive extruder.
W
Z
Z offset
The fine adjustment of the nozzle height above the plate after leveling. Too high and the first layer won’t stick; too low and the nozzle scrapes the plate.