Glossary
Plain-English definitions for 3D printing terms, A–Z.
B
Bed leveling
The process of making the print bed parallel to the nozzle's travel plane, ensuring a consistent first layer.
Manual leveling uses knobs and a paper feeler gauge; assisted leveling uses a probe to guide manual knobs; automatic leveling uses a probe and motorized z-screws to compensate without user action.
Bedslinger
An FDM printer where the build plate moves back and forth on the Y axis while the toolhead moves on X and Z.
A 'bedslinger' (or moving-bed Cartesian) printer moves the build plate rapidly in the Y direction to deposit each layer, while the toolhead travels left-right on X and the bed indexes down on Z. It is the classic, inexpensive desktop layout (e.g. the Ender 3). The moving bed limits top speed compared to CoreXY and can cause issues with tall prints, but the design is simple, cheap and well understood.
Bowden
An extruder configuration where the drive motor is fixed to the frame and filament is pushed through a long PTFE tube to the hotend.
A Bowden extruder mounts the stepper and drive gear on the printer frame rather than on the moving toolhead. Filament travels through a PTFE (Bowden) tube to the hotend. This keeps the moving mass low for speed, but the long, springy path makes retraction tuning harder and struggles with flexible filament. It is common on budget bedslinger printers.
Bowden
A filament feed where the extruder motor is mounted on the frame and pushes filament through a long PTFE tube to the hotend.
Bowden setups keep the extruder motor on the frame, reducing moving mass and enabling faster travel, but make retraction and flexible filaments harder to tune.
Build volume
The maximum part size (X × Y × Z, in mm) a printer can produce.
Build volume is the largest object a printer can create, given as X × Y × Z in millimetres (e.g. 256 × 256 × 256 mm). It is a hard mechanical limit set by the frame and axis travel. Larger volumes allow bigger single parts or more parts per batch, but large prints are more sensitive to warping and bed adhesion. Volume in litres is (X×Y×Z)/1,000,000.
Build volume
The maximum part size a printer can produce, defined by its X, Y and Z travel limits.
Build volume is usually given in mm as X × Y × Z and in liters (X×Y×Z / 1000). Larger volumes allow bigger single parts but cost more and demand a stiffer frame.
C
CoreXY
A motion system where two belts drive the print head along X and Y, keeping the motors stationary for fast, precise movement.
In a CoreXY kinematics, two belts and a set of pulleys transfer motor rotation into X and Y carriage movement. Both motors contribute to each axis, which keeps the moving mass low and allows high acceleration and speed. CoreXY is common on modern enclosed FDM printers.
CoreXY
A belt-driven motion architecture where two motors jointly control X and Y movement, keeping the mass low and fast.
CoreXY is a kinematic arrangement used in many modern desktop 3D printers. Two stepper motors drive a crossed belt system so that both motors contribute to X and Y movement; moving one motor moves the carriage diagonally. Because the motors stay stationary (mounted to the frame) and only the lightweight carriage moves, CoreXY can achieve high speeds and accelerations with low ringing. It is the basis of most fast prosumer FDM machines.
D
Direct drive
An extruder setup where the drive gear sits directly on the hotend, pushing filament straight into the nozzle.
Direct drive improves retraction and is all but required for flexible filaments like TPU, at the cost of a heavier, slower print head.
Direct drive
An extruder configuration where the filament pusher is mounted directly on the moving toolhead, right above the hotend.
In a direct-drive extruder the drive gear that pushes filament sits directly on the printhead, a few centimeters above the nozzle. The short filament path makes it excellent for flexible materials like TPU and gives responsive retraction. The trade-off is extra moving mass on the toolhead, which can limit top speed compared to a Bowden setup.
H
Hardened nozzle
A wear-resistant nozzle (hardened steel or ruby) required for abrasive filaments like carbon-fiber or glow-in-the-dark.
Standard brass nozzles erode quickly when printing abrasive filaments — carbon-fiber-filled, glass-filled, glow-in-the-dark and some metal-filled materials. A hardened steel (or ruby/tungsten) nozzle resists that abrasion and lasts indefinitely, at the cost of slightly lower thermal conductivity (so a higher temperature may be needed). Use one whenever a filament is marked abrasive.
Heated chamber
An enclosure that warms the air around the print to reduce warping and improve layer strength with high-temp materials.
A heated chamber prevents uneven cooling that causes warping, splitting and layer delamination, and is required for stable ABS, ASA and PC printing.
Heated chamber
An enclosed, actively warmed build volume that keeps the printed part warm to reduce warping and internal stress.
A heated chamber warms the air inside an enclosed printer (often to 40–70 °C) so that high-temperature engineering materials like ABS, ASA and PC cool slowly and evenly. This dramatically reduces warping, delamination and internal stress. It is essential for reliable ABS/PC printing and common on prosumer and professional FDM machines.
Hotend
The heated assembly that melts filament and extrudes it through a nozzle.
The hotend is the business end of an FDM printer. It comprises a heater block (with a cartridge heater and thermistor), a heatbreak that isolates the hot zone from the cold side, and a nozzle with a small orifice (commonly 0.4 mm). Filament is melted in the hotend and forced out by the extruder. Hotend max temperature (e.g. 300 °C) determines which materials a printer can run.
I
IDEX
Independent Dual Extruder — two separate print heads that can move independently on the X axis.
IDEX printers can print duplicate or mirror parts simultaneously, or combine two materials without cross-contamination. They are popular for soluble supports and multi-material work.
IDEX
Independent Dual Extruder — two separate toolheads, each with its own X carriage, on one printer.
IDEX (Independent Dual Extruder) places two complete printheads on separate X carriages that can move independently. This enables true multi-material printing without filament swaps, mirror and duplicate modes (printing two copies at once), and clean support material. Unlike a single-nozzle multi-material system, IDEX never needs to purge between colors, but the hardware is more complex and expensive.
K
Klipper
Open-source 3D-printer firmware that runs on a companion computer (often a Raspberry Pi) for high-speed, precise motion control.
Klipper offloads motion calculations to a host computer, enabling higher step rates, input shaping and pressure advance. Many modern printers run Klipper or a Klipper derivative.
Klipper
Open-source 3D printer firmware that offloads motion calculations to a host computer for higher speeds.
Klipper is a popular open-source firmware that runs the motion planner on a more powerful host (a Raspberry Pi or similar) rather than on the printer's 8-bit board. The host sends precise step timings to the microcontroller, enabling higher speeds, pressure advance, input shaping (resonance compensation) and easy multi-board configs. It is the firmware of choice for high-performance and modded FDM printers.
L
Layer height
The thickness of each printed layer in the Z axis; smaller layers mean smoother surfaces and longer print times.
Layer height is the vertical step between deposited layers, typically 0.05–0.30 mm on FDM and 0.01–0.05 mm on resin. Lower layer heights give smoother surfaces and finer detail but increase the number of layers and therefore print time. It is a slicer setting, not a fixed machine property, and is bounded by the nozzle diameter (FDM) or the resin's cure depth (resin).
M
MSLA
Masked Stereolithography — resin printing using an LCD mask over a UV LED array to cure a whole layer at once.
MSLA (Masked Stereolithography) is the dominant consumer resin technology. A UV LED array shines through an LCD screen that acts as a per-pixel mask, curing an entire layer of resin in one exposure. This is faster than laser-traced SLA and much cheaper to build, which is why nearly all desktop resin printers under $1,000 are MSLA. Resolution is set by the LCD pixel pitch (the XY resolution).
P
PEEK
A high-performance engineering thermoplastic with excellent heat and chemical resistance, printed on specialized high-temp FDM machines.
PEEK needs a heated chamber (often 80–120 °C) and a high-temp nozzle (400 °C+). It is used in aerospace, medical and industrial applications.
PEI
Polyetherimide — the coated spring-steel build surface that most modern FDM printers print on.
PEI (Polyetherimide) is a high-temperature polymer applied as a thin coating to a spring-steel or flexible sheet that forms the print bed. PLA, PETG and most filaments stick to a heated PEI surface without glue or tape and release cleanly once the bed cools. Textured PEI gives a matte, slightly rough bottom finish; smooth PEI gives a glossy bottom and is preferred for some materials. It is the de-facto standard build surface on consumer FDM printers.
PEI
Polyetherimide — a popular build-plate surface that grips filament when hot and releases it when cool.
PEI (polyetherimide) is a thermoplastic that grips hot filament without glue. Textured PEI gives a matte first-layer finish; smooth PEI gives a glossy finish. Prints release once the bed cools.
R
Resin
A photopolymer liquid cured by light to form a solid print, used in SLA, MSLA and DLP resin printers.
Resin printing cures liquid photopolymer layer by layer. It produces fine detail and smooth surfaces but requires washing, curing and careful handling of toxic resin.
S
SLA
Stereolithography — a resin 3D-printing process that cures liquid photopolymer with a UV laser, one layer at a time.
SLA produces extremely fine detail and smooth surfaces, used for jewelry, dental and engineering models. MSLA-LCD printers are a faster, cheaper variant using an LCD screen to mask a UV light source.
Slicer
Software that converts a 3D model into the toolpath and settings a printer understands (G-code).
A slicer takes a 3D model (usually an STL or 3MF file) and 'slices' it into horizontal layers, generating the G-code instructions (movements, speeds, temperatures, retractions) the printer follows. Common slicers include Cura, PrusaSlicer, OrcaSlicer and Bambu Studio. Settings like layer height, infill, supports and temperatures are chosen in the slicer, not on the printer.
X
XY resolution
The smallest feature size a resin printer can reproduce in the horizontal plane, set by the LCD pixel pitch.
On an MSLA resin printer, XY resolution equals the LCD pixel size — typically 25–50 µm. It determines the finest horizontal detail and surface smoothness the printer can produce (independent of layer height, which is the Z resolution). Smaller pixels mean crisper miniatures but slower prints, since each layer still needs a full exposure.