3D Printing Glossary: Terms Explained Simply

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Lisa Ernst · 22.11.2025 · Technology · 9 min

We know this situation well: Your 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. Suddenly, dozens of sliders blink in the menu, from Retract Speed to Z-Offset. In the workshop at 33d.ch, we repeatedly see confused faces at exactly this point – and a pile of half-finished failed prints.

If you understand the language of 3D printing, you can solve problems much more effectively: Instead of 'just fiddling with something', you know which adjustment screw is responsible for what. This glossary summarizes the most important practical terms – with typical error patterns, concrete guideline values, and honest anecdotes from our everyday life.

How FDM 3D Printing Works (So 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 part is created from thousands of these thin layers.

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

A small recommendation from the workshop: When you start with a new printer or material, take 10-15 minutes and go through this glossary once side-by-side with your slicer. You'll immediately recognize which sliders are responsible for what – this will save 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 workshop at 33d.ch, we often see: The geometry is correct, the slicer settings are halfway okay – but the material doesn't suit the application. For example, a PLA phone holder in a hot car will not last nearly as long as 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 of 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, we at 33d.ch 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 in Comparison (Guideline Values)

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

Material Nozzle Temperature* Bed Temperature* Typical Properties & Use
PLA ca. 190–220 °C 20–60 °C easy to print, hardly any warping, ideal for decoration, prototypes, indoor enclosures
PETG ca. 220–250 °C 70–90 °C tougher than PLA, more temperature-resistant, slightly "sticky", good for brackets, outdoor applications
ABS ca. 230–250 °C 90–110 °C heat-resistant, impact-resistant, prone to warping, prints best in an enclosed case

*Guideline values that vary slightly depending on the manufacturer and printer. When in doubt, the information on the filament spool takes precedence.

Exactly this classic happened to us at the beginning: We used standard profiles from the slicer, but the finished PLA parts were placed directly next to the heater in the hot storage room. Within a few weeks at the latest, brackets were bent and clips were brittle. Since then, we print functional parts that are exposed to heat and UV light almost exclusively from PETG or ABS – PLA is reserved for prototypes, models, and decorative projects.

Slicer Settings Explained: Infill, Layer Height & Co.

Initially, slicers seem like a cockpit with too many switches. However, in practice, there are a few core terms that you really need to master. You can fine-tune the rest gradually later.

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

Quelle: 3dnatives.com

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

Infill – the interior of your part

Infill is, simply put, the interior 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 holders, 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 use 30-50% and 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 detailed figures at 0.12–0.16 mm. If you're unsure, start with 0.2 mm and test in both directions.

Perimeter / Walls

Perimeters are the outer walls of your part. More walls significantly increase stability without needing to increase the infill. A mechanically stressed hook with 3 perimeters and 25% infill often holds 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, that increases the contact area. A raft is a multi-layer, standalone surface under the model. We use brims almost daily, rafts only in special cases – they significantly increase material consumption and post-processing, but are worthwhile for extremely difficult geometries.

Bed Leveling

During 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".

Whether using the paper method or an automatic sensor: We always run a simple leveling test after major modifications or transport. If even the first layer is uneven, it's hardly worth letting the entire print run to completion.

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 is brutally squashed; if it's too large, the lines remain apart 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 cleanly 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 toolpaths layer by layer. When we're looking for a "mysterious" error in support, we almost always first look at the G-code preview: it mercilessly shows, for example, if support is landing in the wrong place or if perimeters are missing.

Retraction pulls the filament back a bit during travel moves to prevent plastic from dripping from the nozzle and creating fine threads ("Stringing") between model areas. Too little retraction leads to cobwebs, too much can damage the filament or cause air bubbles.

Retraction

Retraction pulls the filament back a bit during travel moves to prevent plastic from dripping from the nozzle and creating fine threads ("Stringing") between model areas. Too little retraction leads to cobwebs, too much can damage the filament or cause air bubbles.

As rough starting values, we often use 4–6 mm retraction at 25–40 mm/s in Bowden systems, and 1–2 mm at similar speeds in Direct Drive systems. 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"

Typical Errors: Warping, Overhang, Stringing & Support

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

Test prints like these squares help with calibration and optimization of printer settings.

Quelle: threedom.de

Test prints like these squares help with calibration and optimization of printer settings.

Warping – when the corners lift

Warping describes the bending of edges upwards when the material shrinks during cooling and partially detaches from the print bed. ABS and larger parts are particularly susceptible to this. The result is warped housings, distorted surfaces, and in the worst case, broken prints.

Overhang & Bridging

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

Support

Support are temporary 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 your evening with pliers and a cutter.

In practice, it has proven effective for us: activate support only where the geometry really needs it (set "Support from build plate only", slightly increase the Support Z distance at contact, 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 while traveling. This looks messy, but it can usually be quickly controlled 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 real projects.

Recommended video on Stringing and Retraction: Stop the stringing with Retraction! (3D Printing 101)

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

Many terms in 3D printing simply describe specific printer components. Knowing what goes where makes troubleshooting much easier.

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

Quelle: fast-part.de

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

Bowden Extruder

In a 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, allowing 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, we reserve one or two machines with Direct Drive for such cases, rather than "forcefully" converting every printer into a TPU specialist.

Direct-Drive Extruder

With 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 responsive to retraction commands and able 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

Simply put, the extruder is the printer's "muscle pack": gears or knurled wheels grip the filament and push it towards the hotend. If the extruder is only chewing on the filament and scraping deep grooves into it, the clamping force is often incorrect – or the nozzle is partially clogged, preventing the material from flowing properly.

Hotend

In the hotend, the filament is brought to its melting temperature. It consists of a heating element, heater block, heat break, 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 molten 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 text, small holes, and miniatures – but the printing time increases noticeably.

In practice, it's worthwhile to deliberately change the nozzle for certain projects instead of trying to solve everything with the standard setup. A 0.8 mm nozzle is a blessing 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 curiosities – they are direct adjustment screws for your print quality. When something goes wrong in our workshop, we practically always resort to the same steps:

This is exactly 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 first, but saves enormous amounts of material, nerves, and failed prints in the long run.

Fits well – possible next topics

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

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

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