Common 3D Printing Terms Every Beginner Should Know

When you first dive into 3D printing, the jargon can feel overwhelming. Layer height, infill, retraction, bridging—it sounds like a foreign language. But understanding these terms makes a real difference when you're ordering prints or discussing your project with a print service.

Here's your no-nonsense guide to the terminology that actually matters.

The Basics: How FDM Printing Works

FDM (Fused Deposition Modeling) is the technology behind many desktop 3D printers. Plastic filament is fed through a heated nozzle, melted, and deposited layer by layer to build an object.

FFF (Fused Filament Fabrication) means the same thing as FDM. The terms are interchangeable—FDM is a trademark held by Stratasys, so the open-source community created FFF to describe the same process.

Materials: The Filaments

Filament is the raw material—a thin plastic thread wound on a spool. Most desktop printers use 1.75mm diameter filament, typically sold in 1kg spools. The type of filament determines your print's strength, flexibility, heat resistance, and appearance.

PLA (Polylactic Acid)

PLA is commonly made from plant-derived feedstocks and is relatively easy to print with low warping. It still produces emissions despite its often mild odor. The PLA guide covers its practical uses and heat limitations.

Best for: Decorative items, prototypes, cosplay pieces, gifts, anything that won't see high heat or heavy mechanical stress.

The catch: Not great above 50-60°C—it'll soften in a hot car. Less impact-resistant than PETG or ABS.

PETG (Polyethylene Terephthalate Glycol)

The middle ground between ease of PLA and strength of ABS. PETG is the same material family as water bottles—tough, slightly flexible, and more heat-resistant than PLA.

Best for: Functional parts, outdoor items, anything that needs some durability. Great for mechanical components that might see stress.

The catch: Slightly stringier to print than PLA, and the surface finish can be glossier (which some people don't prefer).

ABS (Acrylonitrile Butadiene Styrene)

The classic engineering plastic—it's what LEGO bricks are made of. Strong, heat-resistant, and can be smoothed with acetone vapor for a glossy finish.

Best for: Functional parts that need heat resistance or durability. Automotive applications, enclosures.

The catch: Requires higher temperatures, tends to warp without an enclosed printer, and produces fumes you shouldn't breathe.

TPU (Thermoplastic Polyurethane)

The flexible stuff. TPU produces rubber-like prints that bend, stretch, and absorb shock.

Best for: Phone cases, gaskets, vibration dampeners, anything that needs to flex.

The catch: Slower to print, requires specific printer configurations, not every service offers it.

Printer Components

Hotend is the business end of the printer where filament gets melted. Temperature here depends on material—typically 200°C for PLA, 240°C for PETG, higher for ABS.

Nozzle is the tiny opening at the end of the hotend where molten plastic comes out. The standard diameter is 0.4mm, which provides a good balance between detail and print speed. Smaller nozzles (0.2mm) can capture finer details; larger ones (0.6mm, 0.8mm) print faster but lose some precision.

Build plate (or print bed) is the surface where a print is built. Smooth and textured plates leave different finishes; adhesion requirements depend on the plate and material combination.

Build volume describes the available printing space along the X, Y, and Z axes. Check the target printer's usable dimensions and leave room for supports and adhesion aids.

Extruder is the mechanism that grips the filament and pushes it toward the hotend. "Direct drive" means the motor is mounted right on the printhead; "Bowden" means the motor is mounted on the frame and pushes filament through a tube. Direct drive handles flexible materials better.

Slicer Settings

A slicer is the software that converts your 3D model into instructions the printer understands. It "slices" your model into layers and generates G-code—the step-by-step commands that tell the printer exactly where to move and how much plastic to extrude.

Layer Height

How thick each horizontal slice of your print is. This is one of the most important settings because it directly affects print quality and time.

• 0.1mm (fine): Maximum detail, smoothest surfaces, but takes roughly twice as long as 0.2mm
• 0.2mm (standard): Good balance of quality and speed—this is where most prints land
• 0.28-0.32mm (draft): Faster prints, visible layer lines, fine for prototypes or hidden parts

The rule of thumb: layer height shouldn't exceed about 80% of your nozzle diameter. With a standard 0.4mm nozzle, that means 0.32mm is roughly the upper limit.

Infill

The internal structure of your print. Instead of printing solid objects (which wastes material and time), printers create a pattern inside the walls.

Infill percentage determines how much of the interior is filled with plastic:

• 10-15%: Good for decorative items that won't bear loads
• 20-30%: Standard for most functional parts
• 40-60%: Heavy-duty applications, parts under stress
• 100%: Completely solid (rarely necessary)

Infill pattern is the geometric structure used inside. Gyroid is currently popular because it provides strength in all directions. Grid and honeycomb are simpler but effective. The pattern choice matters more for functional parts than decorative ones.

Walls and Shells

The outer perimeter of your print is called walls or shells. More walls mean stronger parts. For most applications, 3-4 walls provide good strength. For decorative items, 2 walls are often enough. Heavy-duty parts might go to 5-6.

Wall thickness contributes more to part strength than infill density in many cases.

Print Features

Supports

When your model has overhangs—parts that extend outward without anything beneath them—the printer needs temporary scaffolding. Supports are automatically generated structures that prop up these sections during printing, then get removed afterward.

An overhang around 45 degrees from vertical is a starting guideline, not a universal cutoff. Material, cooling, layer height, and geometry change the limit. The support-free design guide compares overhangs, bridges, and design alternatives.

Bridging

When the printer needs to span a gap between two points—like printing the top of a doorway—it's called bridging. The printer extrudes in midair, relying on the material to cool and solidify fast enough to hold its shape.

Short bridges work great. Long bridges may sag. Cooling and speed adjustments help, but some designs simply need supports for long spans.

Brim and Raft

Adhesion helpers for tricky prints:

• Brim: A single-layer "collar" around the base of your print that increases bed contact. Easy to remove, minimal material use.
• Raft: A full multi-layer platform under your print. Uses more material but provides maximum adhesion for problematic models.

Skirt is different—it's a few loops around (not touching) your print that primes the nozzle before the real printing starts.

Common Issues You'll Hear About

Warping happens when corners lift off the build plate as the print cools. Some materials (ABS especially) are prone to this. Heated beds, enclosures, and brims help prevent it.

Stringing refers to thin wisps of plastic stretched between parts of a print, like cobwebs. It's caused by material oozing from the nozzle during travel moves. Properly tuned retraction settings—which pull filament back when the nozzle moves—minimize stringing.

Layer adhesion (or lack thereof) determines whether your layers bond together into a solid part or separate under stress. Temperature, speed, and material all affect adhesion. Poor adhesion leads to delamination—layers separating from each other.

Elephant's foot is when the first layer squishes out wider than it should, creating a slight bulge at the base. Usually a sign that the nozzle is too close to the bed or first layer temperature is too high.

File Formats

STL (STereoLithography): The industry standard. Contains only geometry—no color, no material info, just the shape. Works everywhere.

3MF: The newer, better format. Includes geometry plus color, material, and other metadata. Use it if your software supports it.

OBJ: Common in 3D graphics. Supports textures and colors. Works for printing but STL or 3MF are usually better choices.

STEP/STP: Native CAD format that preserves design intent. Great for editing but needs to be converted to mesh format before printing.

Terms Worth Knowing When Ordering

Print orientation is which direction your model faces on the build plate. This affects strength (layers are weakest across their bond lines), surface quality, and support needs. A good print service will orient your model optimally.

Tolerance refers to dimensional accuracy—how close the final print is to your design dimensions. FDM printing typically achieves ±0.2mm on a well-tuned machine.

Post-processing covers anything done after printing: removing supports, sanding layer lines, painting, assembly. Some prints come off the bed ready to use; others need cleanup.

Why This Matters

Understanding these terms helps you communicate with your print service, make informed decisions about materials and settings, and set realistic expectations for your projects.

Try opening a model in a slicer and finding each setting in this glossary. The learning resources offer a starting point for exploring the tools and process.