3D Printing Glossary

3D printing, also called additive manufacturing, builds a physical object one thin layer at a time from a digital 3D model. The printer follows instructions from your slicer to lay down each layer until the part is finished.

Bed leveling means adjusting the build plate so the gap between nozzle and bed is even across the whole surface. A well-leveled bed is the most important factor in a good first layer. Many newer printers can do this automatically.

The build plate, or print bed, is the surface where your model is printed. It is often heated to help the first layer stick. Common surfaces include smooth PEI, textured PEI and glass.

FDM (Fused Deposition Modeling), sometimes called FFF, is the most common type of consumer 3D printing. A heated nozzle melts plastic filament and deposits it layer by layer. Most beginner printers are FDM printers.

Filament is the plastic material, sold on spools, that an FDM printer melts and extrudes. The most common size is 1.75 mm in diameter. Popular types include PLA, PETG, ABS and TPU.

G-code is the simple text language a 3D printer reads. Each line is a command, such as move to a position, heat the nozzle, or extrude a bit of filament. Your slicer creates it for you, so you rarely need to write it by hand.

Infill is the internal structure printed inside a part, set as a percentage. Higher infill makes a part stronger but uses more filament and time. Around 10 to 20 percent is plenty for most decorative prints.

Layer height is the thickness of each layer the printer lays down, usually measured in millimeters. 0.2 mm is a common balance of quality and speed. Lower values give smoother surfaces but increase print time.

The nozzle is the small heated tip of the hot end where molten filament exits. The most common size is 0.4 mm. Smaller nozzles give finer detail, and larger ones print faster.

PLA (polylactic acid) is a plant-based plastic and the usual first choice for beginners. It prints at relatively low temperatures, rarely warps, and comes in countless colors. It softens in high heat, so it is not ideal for parts left in a hot car.

Retraction is when the extruder briefly pulls filament backward as the nozzle travels between parts of a print. It reduces oozing and the thin “strings” that can appear between features. Tuning retraction settings is a common fix for stringing.

A slicer is the program that “slices” a 3D model into layers and generates the G-code your printer follows. It is also where you choose settings such as layer height, infill and print speed. Cura and PrusaSlicer are popular free examples.

STL is the standard file format for 3D models used in printing. It describes the surface of an object as a mesh of triangles. You load an STL file into your slicer to prepare it for printing.

Supports are temporary structures printed beneath overhangs so they do not droop in mid-air. They are removed after printing. Good model orientation can often reduce or avoid the need for them.