3D printing glossary

Plain-English definitions for the terms you'll encounter weekly in the 3D printing world — from "ABS" to "Z-offset". Where beginners commonly get tripped up, we've added a brief note. Use Ctrl/Cmd+F to jump to a term.

A

ABS

Acrylonitrile Butadiene Styrene. Strong, heat-resistant FDM filament that prints around 240 °C and warps badly without an enclosure. Emits styrene fumes — ventilate.

Acceleration

How quickly the toolhead changes speed, in mm/s². Higher = faster prints; lower = smoother. Limited by your printer's rigidity and mass.

AMS (Automatic Material System)

Bambu Lab's multi-spool feeder unit that holds 4 spools and feeds them to the printer for multi-colour or auto-refill prints. Equivalent to Prusa MMU.

Annealing

Heating a printed part (typically 60–120 °C in an oven for 1–6 hours) to relieve internal stress and improve strength. Causes some shrinkage.

ASA

Acrylonitrile Styrene Acrylate. Like ABS but UV-resistant. Used for outdoor parts. Similar print settings to ABS.

B

Bed

The flat heated surface a print is built on. Usually a removable flex plate over a heated aluminum or glass bed.

Bed leveling

Setting the bed to be parallel to the X/Y motion plane. "Auto bed leveling" probes the bed and compensates in software (mesh leveling).

Belt

The toothed rubber belt that connects the stepper motor to the moving axis. GT2 (2 mm pitch) is standard.

Benchy

The "3DBenchy" boat — a standard test print designed to stress every aspect of FDM (overhangs, small features, bridges). If your Benchy prints well, most things will.

Bowden

A type of extruder where the motor is mounted on the frame and pushes filament through a PTFE tube to a remote hotend. Lighter toolhead = faster acceleration, but worse for TPU.

Bridge / Bridging

Printing across a gap with no support underneath. Most printers bridge cleanly up to 20 mm; some up to 50.

Brim

A flat single-layer ring of plastic around the base of a print, helping adhesion and preventing warping. Snap off after.

C

Cartesian

Printer kinematics where each axis (X, Y, Z) is moved by its own motor in a linear direction. Includes "bedslinger" (Ender 3-style, where the bed moves in Y) and "i3" designs.

Cold pull

Cleaning the nozzle by inserting filament, letting it partially cool, then pulling it out forcefully — pulling out any contamination stuck inside the nozzle.

CoreXY

Printer kinematics where both X and Y motion is driven by two motors working together. Allows a moving toolhead while the bed stays stationary (no Y inertia). Used by Voron, Bambu X1, Prusa CORE One.

D

Direct drive

An extruder where the motor is mounted directly on the toolhead, with very short distance to the hotend. Required for TPU; helps with retraction performance.

Dual extruder

A printer with two hotends, allowing two materials/colours in one print (with potential cross-contamination from oozing).

E

E-steps

Extruder steps per millimetre — the firmware value that converts requested filament length to motor pulses. Calibrate it so 100 mm requested = 100 mm actually extruded.

Enclosure

A box around the printer that retains heat (essential for ABS/PC/nylon) and contains fumes.

Extruder

The motor and gear assembly that pushes filament into the hotend.

F

FDM / FFF

Fused Deposition Modeling / Fused Filament Fabrication. The technology of building a part by melting and depositing thermoplastic filament layer by layer. The two terms mean the same thing — "FDM" is a Stratasys trademark, "FFF" is the open-source equivalent name.

Filament

The thermoplastic wire that feeds into the printer. Standard diameters: 1.75 mm (most consumer printers) and 2.85 mm (some Ultimaker/older printers).

First layer

The bottom-most layer of a print. Critical for bed adhesion; most print failures happen here.

Flex plate

The removable spring steel sheet with a PEI or textured coating that prints stick to. Pop off the printer, flex it, and prints release cleanly.

Flow rate

The volume of plastic extruded per second (mm³/s). Hardware-limited by the hotend's melting capacity.

G

Gantry

The frame structure that holds the moving toolhead. CoreXY printers have a "gantry" that moves in X&Y.

Gcode

The plain-text instruction file the printer reads, generated by the slicer. Lines like G1 X100 Y100 F3000 tell the printer to move.

Ghosting

Ripples on vertical walls caused by mechanical vibration. Reduce acceleration or run input shaping.

Gyroid

An infill pattern based on a continuous 3D curved surface. Strong in all directions, prints fast.

H

Heat creep

When heat travels up the hotend's thermal break to the cold zone, melting filament where it shouldn't be melted. Causes mid-print clogs.

Heat break

The thin tube between the hot zone and the cold zone of a hotend, designed to limit heat transfer upward.

Heated bed

The temperature-controlled build platform. Helps adhesion and reduces warping.

HMS

Bambu Lab's "Health Management System" — their error code system.

Hotend

The complete assembly of heater block, nozzle, heat break, and cooling fins that melts the filament.

HTPLA

High-Temperature PLA. After printing, annealed (heated) to crystallise the plastic and improve heat resistance up to ~120 °C. Shrinks during annealing.

I

IDEX

Independent Dual Extruders. Two separate toolheads, each with its own motion. Allows simultaneous printing of two copies and clean dual-material prints.

Infill

The internal structure of a print — not solid plastic but a pattern (gyroid, grid, etc.) at a percentage density.

Input shaping

Firmware feature that pre-compensates for mechanical resonances, letting you print faster without ringing. Aka "resonance compensation".

J

Jerk

The instantaneous speed change allowed at corners. Higher = faster but rougher. Modern firmware mostly replaces it with junction deviation.

Junction deviation

A geometry-aware replacement for jerk that smoothly handles corners.

K

Klipper

An open-source 3D printer firmware that runs on a Raspberry Pi (or similar) connected to the printer's mainboard. Enables input shaping, pressure advance, and high-speed printing on hardware that wouldn't otherwise support it.

L

Layer height

The Z-distance between layers, typically 0.08–0.32 mm. Smaller = smoother but slower.

Layer shifting

A failure where the print suddenly shifts in X or Y partway up. Caused by skipped motor steps or belt slipping.

Lightning infill

An infill pattern that only exists where it's needed to support the top layers. Saves time and material.

Linear advance

Marlin's name for pressure advance.

M

Magic numbers

Layer heights that are exact multiples of the Z-axis step size (0.04 mm for most printers), avoiding rounding artifacts. 0.08, 0.12, 0.16, 0.20, 0.24 are all "magic".

Marlin

Open-source 3D printer firmware that ships on most consumer printers. Stable, widely supported.

Mesh leveling

Auto-bed-leveling that probes a grid of points across the bed and compensates Z in software for any unevenness.

MMU

Multi-Material Unit. Prusa's spool selector for multi-colour / multi-material prints.

N

Nozzle

The brass (or hardened steel) tip with a small hole (typically 0.4 mm) through which melted plastic flows. Hardened steel required for carbon/glass-fibre filaments.

NTC

Negative Temperature Coefficient. The most common thermistor type in 3D printers.

O

OctoPrint

Open-source web interface for controlling 3D printers from a phone or laptop. Runs on a Raspberry Pi connected via USB.

Overhang

Any part of the print that extends out without direct support below. Manageable up to about 50° from vertical without support.

P

PA-CF / PA-GF

Polyamide (nylon) reinforced with chopped carbon (CF) or glass (GF) fibres. Stiff, abrasion-resistant. Requires hardened nozzle.

PEEK

Polyether Ether Ketone. Engineering thermoplastic requiring 400+ °C hotend. Industrial-grade only.

PEI

Polyetherimide. The textured or smooth surface coating on most modern flex plates. Excellent adhesion; long-lasting.

Perimeter

A loop of plastic at the outside (or inside, on hollow features) of a layer. Same as "wall". Usually 3–5.

PETG

Polyethylene Terephthalate Glycol-modified. Strong, slightly flexible, food-contact-tolerant, less brittle than PLA. Prints at 230–250 °C.

PID tuning

Calibrating the firmware's temperature control loop. Run after a hotend change. Prevents temperature oscillation.

PLA

Polylactic Acid. The easiest FDM filament — low warping, low fumes, prints at 200 °C, brittle at room temperature, softens around 60 °C.

Pressure advance

Firmware feature that pre-emptively adjusts extrusion at corners to compensate for melt-zone pressure lag. Reduces blobs and gaps.

PTFE

Polytetrafluoroethylene (Teflon). Used as a low-friction tube for Bowden feeding. Off-gases above 250 °C; replaced by all-metal hotends for high-temp materials.

Purge

Extruding filament that won't end up in the print, used to flush the nozzle (between colour changes, before printing).

Q

QR code (in slicing)

Some printers (Bambu, X1) use QR codes on filament spools for auto-identification.

R

Raft

A multi-layer base printed under the model to help adhesion and provide a flat starting surface. Uses more material than a brim; mostly obsolete with modern PEI flex plates.

Resin

Different 3D printing technology (SLA/MSLA) using UV-cured liquid resin. Higher detail than FDM; messier; smellier.

Retraction

Pulling filament backward briefly during a travel move to prevent oozing. Typical: 0.4–1.0 mm for direct drive, 2–5 mm for Bowden.

Ringing

Same as ghosting.

S

SCARA

Selective Compliance Articulated Robot Arm. A rare printer kinematics style with rotational joints.

Seam

The visible line where each layer starts and ends. Slicers can hide it on a corner or randomise it.

Skirt

A few loops of plastic around the print (not touching it) used to prime the nozzle and verify flow before the first layer.

Slicer

Software that converts a 3D model (STL/3MF) into the layer-by-layer gcode instructions the printer follows. Examples: Bambu Studio, OrcaSlicer, PrusaSlicer, Cura.

Spool

The plastic or cardboard reel that filament ships on.

SLA

Stereolithography. Resin 3D printing using a UV laser. Now mostly replaced by MSLA in consumer printers.

Stepper

Stepper motor. The kind of motor used for axis movement in 3D printers. Moves in discrete steps (e.g., 200 steps per revolution).

STL

Standard Tessellation Language. The classic 3D model file format — triangulated surface mesh. Slowly being replaced by 3MF (which carries metadata).

Stringing

Thin strings of plastic between separated parts of a print, caused by ooze during travel. Fixed with retraction and dry filament.

Support

Sacrificial scaffolding printed beneath overhangs, removed after printing.

T

Thermal runaway

Firmware safety check that triggers if the heater/thermistor feedback loop loses sync, indicating possible fire risk.

Thermistor

Temperature-sensitive resistor that measures hotend or bed temperature.

3MF

Modern 3D model file format that carries colour, materials, print settings, and metadata alongside geometry. Increasingly replacing STL.

TPU

Thermoplastic Polyurethane. Flexible rubber-like filament. Requires direct drive.

U

Underextrusion

Not enough plastic being laid down — visible as gaps, weak walls, or skipped lines.

V

Vase mode

A slicer mode that prints with a single spiralising wall, no infill, no top — producing thin-walled vase-shaped prints from a single continuous extrusion.

Volumetric flow

The volume of melt the hotend can push per second (mm³/s). Often the actual speed bottleneck on consumer printers.

Voron

An open-source DIY CoreXY 3D printer design with a passionate community. Known for speed and quality with significant build effort.

W

Wall

Same as perimeter.

Warping

Corners of a print lifting off the bed as the plastic cools and shrinks. Worst on ABS and large flat parts.

Z

Z-hop

Lifting the nozzle slightly during travel moves to avoid bumping the print. Useful but slows the print.

Z-offset

The Z height at which the firmware considers the nozzle to be touching the bed (usually slightly negative, ~−0.05 to −0.20 mm, to compress the first layer for adhesion).

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