3D Printing Glossary: Terms Explained Simply

Lisa Ernst · 22.11.2025 · Technology · 9 min

We know it well: The first own 3D printer is on the table, PLA is loaded, the Benchy is loaded – and then you stumble over terms like Infill, Flow, Brim or Bowden in the slicer. In the menu, dozens of sliders suddenly flash, from Retract Speed to Z-Offset. In the 33d.ch workshop, we repeatedly see bewildered faces at this point – and a pile of half-finished failed prints.

Anyone who understands the language of 3D printing can solve problems much more effectively: Instead of "just adjust something", you know which adjustment screw is responsible for what. This glossary summarizes the most important practical terms – with typical error patterns, concrete guidelines, and honest anecdotes from our daily life.

Source: Own representation

How FDM 3D printing roughly works (so that the terms make sense)

Most home, school, and office printers work with FFF/FDM. A thermoplastic filament is pulled from a spool into the extruder, heated in the hotend, and laid layer by layer onto the print bed. Your component is created from thousands of these thin layers.

• Filament: the plastic thread on the spool, usually 1.75 mm in diameter.
• Extruder: puts the filament under pressure and pushes it towards the hotend.
• Hotend & Nozzle: here the material is melted and deposited as a thin strand.
• Print bed & motion system: ensure that each layer lands in the correct position.

Before printing starts, a slicer translates your 3D model (STL or 3MF) into G-code – i.e., concrete travel paths, temperatures, and fan speeds for the printer. Many manufacturers offer their own glossaries and knowledge bases; we focus here on the terms that repeatedly cause questions in practice for hobby makers, schools, and SMEs.

A small tip from the workshop: When you start with a new printer or material, take 10-15 minutes and go through this glossary side-by-side with your slicer. You'll immediately recognize which sliders are responsible for what – saving many hours of trial and error later.

Material Terms: Filament, PLA, PETG & ABS

Material choice is one of the biggest levers for stable, everyday-usable parts. In the 33d.ch workshop, we often see: the geometry is correct, the slicer settings are more or less okay – but the material doesn't suit the intended use. For example, a phone holder made of PLA in a hot car will last significantly less time than the same geometry made of PETG.

Filament

Filament is the thin plastic thread on the spool from which FDM printers build their parts. Common diameters are 1.75 mm, and spools are usually 750 g or 1 kg. There are countless variations such as PLA, PLA-Plus, PETG, ABS, ASA, Nylon, or special mixtures filled with glass and carbon fibers.

In practice, at 33d.ch, we first pay attention to three things: diameter tolerance, winding on the spool, and moisture. Poorly wound or highly fluctuating filaments lead to uneven flow; moist material causes bubbles and rough surfaces. A short test print (calibration cube, thin wall) is always worthwhile here.

PLA, PETG, and ABS Comparison (Guidelines)

Manufacturers specify their own temperature ranges, but for beginners, typical ranges have proven effective in practice:

*Guidelines that may vary slightly depending on the manufacturer and printer. When in doubt, the specifications on the filament spool take precedence.

Exactly the classic happened to us at the beginning: We adopted standard profiles from the slicer, but the finished PLA parts were placed right next to the heater in the hot warehouse. After a few weeks at the latest, brackets were crooked and clips were brittle. Since then, we only print functional parts that are exposed to heat and UV light almost exclusively from PETG or ABS – PLA remains for prototypes, models, and decorative projects.

Slicer Settings Explained: Infill, Layer Height & Co.

Slicers initially seem like a cockpit with too many switches. In practice, however, there are a few core terms that you really need to master. You can fine-tune the rest gradually later.

Source: 3dnatives.com

The typical 3D printing workflow: From digital modeling to the finished physical object.

Infill – the inside of your component

Infill is, put simply, the inside of your part: a grid or honeycomb structure inside that supports the outer walls. Together with the perimeters, it determines how stable, heavy, and material-intensive your print will be in the end.

For decorative objects and simple brackets, we at 33d.ch often choose 10-20% infill with a simple grid pattern. For functional parts – such as clamping jaws, tool holders, or machine parts – we tend to be at 30-50% and use more stable patterns like Gyroid or Cubic, depending on the load. We only use 100% infill when it's absolutely necessary; otherwise, it costs unnecessary time and filament.

Layer Height

The layer height indicates how thick each printed layer is. Typical values with a 0.4 mm nozzle range from 0.1 mm (very fine) to 0.28 mm (fast, but visibly stepped). A common guideline: the layer height should be at most about 80% of the nozzle diameter – so about 0.32 mm for a 0.4 mm nozzle.

Our rule of thumb: We usually print prototypes and brackets at 0.2–0.24 mm, and highly detailed figures at 0.12–0.16 mm. If you're unsure, start with 0.2 mm and test your way in both directions.

Perimeter / Walls

Perimeters are the outer walls of your component. More walls significantly increase stability without having to increase the infill. A mechanically stressed hook with 3 perimeters and 25% infill will often hold better than a part with only 2 walls but 40% infill.

Brim & Raft for better adhesion

A brim is a single-layer "skirt" around your part, connected to the first layer, which increases the contact area. A raft is a multi-layer, self-standing surface beneath the model. We use brims almost daily, rafts only in special cases – they massively increase material consumption and post-processing, but are worthwhile for extremely difficult geometries.

Bed Leveling

With bed leveling, you ensure that the distance between the nozzle and the print bed is the same at all corners. Only then will the first layer adhere reliably – without the nozzle scratching the bed or the lines hanging "in the air".

Z-Offset

The Z-offset is the fine height correction between the mechanical zero point of the printer and the actual position of the nozzle above the bed. If the distance is too small, the first layer will be brutally squeezed; if it's too large, the lines will lie next to each other and adhere poorly.

A pragmatic approach: first roughly level the bed, then use a simple first-layer test to adjust the Z-offset in 0.02–0.05 mm steps until the lines lie neatly next to each other and are still recognizable.

G-code

G-code is the sequence of individual command lines that your printer understands – from "move the nozzle to X/Y/Z" to temperatures and fan speeds. In the slicer, you can view the path progressions layer by layer. When we're looking for a "mysterious" error in support, we almost always look at the G-code preview first: It mercilessly shows whether, e.g., support is landing in the wrong place or perimeters are missing.

Retraction

Retraction pulls the filament back a bit during travel moves, so that no plastic drips from the nozzle and fine threads ("stringing") form between model areas. Too little retraction leads to cobwebs, too much can damage the filament or cause air bubbles.

As rough starting values for Bowden systems, we often use 4-6 mm retraction at 25-40 mm/s, and for direct drive systems, rather 1-2 mm at a similar speed. It's important to test changes incrementally – ideally with a small stringing test model, before risking large prints.

Mini-Checklist: If the print looks "weird"

• Print hollow and unstable inside? → Increase infill percentage and perimeters.
• Steps on curves very visible? → Reduce layer height.
• Lots of threads between parts? → Check retraction and nozzle temperature.
• Parts breaking on the outer walls? → More perimeters instead of just more infill.

Typical errors: Warping, Overhang, Stringing & Support

When a new material or a new printer arrives in our workshop, we consciously invest a few hours in test prints: cubes, towers, bridges. This way, we provoke typical errors and quickly see which terms in the slicer we need to adjust.

Source: threedom.de

Test prints like these squares help with calibrating and optimizing printer settings.

Warping – when the corners lift up

Warping describes the lifting of edges when the material shrinks during cooling and partially detaches from the print bed. ABS and larger parts are particularly prone to this. The result is crooked enclosures, warped surfaces, and in the worst case, broken prints.

• Typical causes: print bed too cold or unsuitable, drafts, too rapid cooling, no brim.
• Quick levers: increase bed temperature, activate brim, use enclosure if necessary, print the first layer slower and a bit thicker.

Overhang & Bridging

Overhangs are areas printed diagonally "into the air"; bridges are horizontal spans between two points. The steeper the angle or the longer the bridge, the more likely strands will sag or break.

• Most printers manage overhangs up to about 45 degrees without support material.
• Longer bridges are more successful with lower speed and stronger part cooling.
• Where possible, a small design trick is worthwhile: round or chamfer edges instead of having them break off vertically.

Support

Supports are temporary support structures that the printer builds under overhangs or free-floating areas. They are removed after printing. Too little support and your layers will sag; too much support and you'll spend the evening with pliers and a cutter.

In practice, we've found it best to: only enable support where the geometry really requires it (set "Support from build plate only", slightly increase contact Z distance, and keep the support density value moderate). This way, undersides remain acceptably clean without you having to dismantle the parts.

Stringing – fine threads between parts

Stringing is the fine threads that hang between two areas of your model when the nozzle continues to lose material during travel moves. This looks messy, but can usually be brought under control quickly with correct retraction settings, slightly lower nozzle temperature, and dry filament.

A practical approach: First, print a small stringing test model, then gradually adjust retraction distance and temperature. If the threads decrease, you can transfer the same settings to your actual projects.

Printer components: Extruder, Bowden, Direct-Drive, Hotend & Nozzle

Many terms in 3D printing simply describe specific printer components. If you know what goes where, troubleshooting becomes much easier.

Source: fast-part.de

The FDM printing process: Layer by layer to the finished object.

Bowden Extruder

In the Bowden setup, the extruder motor is located on the printer frame. The filament is pushed through a PTFE tube (Bowden tube) to the hotend. The moving mass on the print head is low, which allows for higher speeds. At the same time, the filament path is longer and more sensitive – especially with flexible materials.

Typically: A Bowden printer handles PLA and PETG without problems, but struggles with very soft TPU filaments. In our workshop, for such cases, we have one or two machines reserved with Direct Drive, instead of "forcing" every printer to become a TPU specialist.

Direct-Drive Extruder

In Direct Drive, the extruder motor is located directly on or very close to the hotend. The filament travels only a short distance to the nozzle. This makes the printer more sensitive to retraction commands and allows it to process flexible filaments much better. The downside: more weight on the print head, which means slightly lower maximum speeds depending on the device.

Extruder

The extruder is, simply put, the "muscle package" of the printer: gears or knurled shafts grip the filament and push it towards the hotend. If the extruder is only milling into the filament and scraping deep grooves into it, the contact pressure is often incorrect – or the nozzle is partially clogged, so the material can no longer flow properly.

Hotend

In the hotend, the filament is brought to its melting temperature. It consists of a heating element, heating block, heatbreak, heatsink, and nozzle. Too cold, and the filament adheres poorly; too hot, and you'll get stringing, threads, and in extreme cases, burnt residues that lead to clogs.

Nozzle

The nozzle is the small opening at the end of the hotend through which the melted filament reaches the print bed. The standard is 0.4 mm, but finer and coarser variants exist. Larger nozzles (0.6–0.8 mm) print large parts significantly faster but produce more visible layers; smaller nozzles (0.25–0.3 mm) are ideal for fine lettering, small holes, and miniatures – but the printing time increases noticeably.

In practice, it's worthwhile to consciously change the nozzle for specific projects instead of trying to solve everything with the standard setup. A 0.8 mm nozzle is a godsend for a large PETG planter – but not so much for detailed logos.

In Summary: How to Use This 3D Printing Glossary

Terms like Infill, Brim, Retraction, or Z-Offset are not theoretical gimmicks – they are direct adjustment screws for your print quality. When something goes wrong in our workshop, we practically always rely on the same steps:

• Change only one term or setting at a time and observe the result.
• Print small test objects instead of immediately risking the large final part.
• Take notes: material, temperature, infill, layer height – this way, you build up your own "best practice profiles" over time.
• For recurring problems (e.g., warping or stringing), specifically search for the corresponding term and adjust the relevant settings.
• Save and name profiles (e.g., "PLA-Standard", "PETG-Outdoor", "ABS-Enclosure") so that successful settings are not lost.

This is how we work at 33d.ch in everyday life: systematically rather than flying blind, with clear terms and clean test series. It costs a bit of time at the beginning, but saves a tremendous amount of material, nerves, and failed prints in the long run.

Recommended video for a quick all-round overview: 3D PRINTING 101: The ULTIMATE Beginner's Guide

If you are mainly struggling with bed leveling, this tutorial might help you: Bed levelling for beginners to achieve a perfect first layer