3D Printer Filament Types: A Complete Overview

How to Make Sense of Filament Families

Picking a filament is not just about color or brand: every material family comes with its own machine requirements, its own printing difficulty, and its own best-fit uses. Per Prusa's documentation, that variety comes down to very different behavior around cooling, moisture, and mechanical stress once the part is done.

Three criteria show up again and again in manufacturer data sheets: the intended use for the finished part, machine requirements (enclosure, hardened nozzle, drying), and how forgiving the material is for a beginner. The table further down summarizes those three criteria for the most common families, with each one broken down afterward and a dedicated guide of its own. None of the families below is universally better than another; each one trades ease of printing for a specific mechanical or visual property, and the right pick depends on the part in front of you.

PLA and PETG: the Everyday Pair

PLA is the easiest material to work with according to Prusa's documentation: low bed temperature, no enclosure needed, and enough tolerance for imperfect settings to make it the default starting filament on nearly every FDM printer.

PETG is the common second filament: Prusa's documentation describes it as inexpensive to run, with higher toughness and heat resistance than PLA, at the cost of a slight stringing tendency that good retraction settings usually fix. PLA vs PETG breaks down the choice in more detail for a specific part. Between the two, PLA usually wins on ease and dimensional accuracy, while PETG wins as soon as the part sees any meaningful mechanical stress or outdoor humidity.

TPU: the Flexible Family

TPU spans a range of Shore A hardness that, per Prusa's documentation, runs from rubber-like materials to stiffer filaments, with most commercial spools sitting between 85A and 100A. The lower the number, the softer the material, and the more it needs its own speed and retraction settings.

A short filament path, ideally direct-drive, cuts down on the jamming that flexible materials are prone to. Prusa's documentation recommends slowing print speed noticeably compared with PLA or PETG to keep extrusion under control.

ABS and ASA: the Family That Wants an Enclosure

ABS and ASA stand apart because they shrink significantly as they cool, with a documented warping risk on open-frame printers per Prusa. A dedicated guide covers bed settings, ventilation, and which enclosed printers fit these two materials.

These filaments are mostly for functional parts or, in ASA's case, outdoor parts, rarely a first print, because of the enclosure-plus-ventilation-plus-drying combination they demand.

Nylon and PC: the Engineering Family

Nylon (PA) and polycarbonate (PC) target high mechanical or thermal stress parts: gears, hinges under repeated flex, components exposed to real heat. Prusa's enclosure guide groups both materials, alongside ABS, ASA, and PP, among the ones that need an enclosure to limit warping.

Nylon is also especially moisture-sensitive: Prusa's documentation recommends drying it for at least four hours below 90 °C (194 °F) before printing, since a wet spool causes bubbling and an uneven surface. Both materials are best suited to users already comfortable fine-tuning a printer.

PVA and BVOH: Soluble Supports

PVA and BVOH are not structural materials but temporary supports: per Prusa's documentation, they print alongside the main filament on a multi-material setup, then dissolve in water after printing, which clears overhangs that would otherwise be impossible to support without leaving marks.

Both filaments need to be stored in a sealed box since they absorb moisture fast. Prusa's documentation notes that BVOH prints better than standard PVA, at a higher cost, and that full dissolution can take several hours depending on water temperature.

Filament Diameter: Why 1.75 mm Became the Standard

The filament market really only uses two common diameters, 1.75 mm and 2.85 mm (sometimes rounded to "3 mm"). Per Prusa's glossary, the 1.75 mm size is the most common worldwide, and every Original Prusa FFF printer ships configured for it; 2.85 mm stays a minority format, mostly tied to older bowden-style extruders or some industrial machines.

Diameter is not just about hopper compatibility: a spool whose thickness drifts along its length throws off the flow rate the firmware expects, regardless of the material's chemistry, and can show up as inconsistent extrusion even when every other setting is correct. It is worth checking on a spool's data sheet before loading it onto a printer that is already dialed in for a specific print temperature profile, right alongside its recommended storage humidity and its rated diameter tolerance.

Dry Storage or an Oven: Two Different Answers to Moisture

Many makers blur two separate actions around moisture: keeping a spool dry in the first place, and drying one that has already absorbed water. Per Prusa's documentation on its sealed storage boxes (dryboxes), a drybox with desiccant slows moisture absorption during printing, but it does not dry an already-wet filament: a soaked spool needs a proper drying oven first, then goes back into the box.

That distinction applies to every family covered above, not just nylon or PVA: the same documentation flags highly hygroscopic engineering polymers such as PEEK, PEKK, and PSU, which need an even more sealed storage setup than a PLA or PETG spool sitting on a shelf. A dedicated filament dryer walks through oven settings and drying times material by material once a spool is already wet, rather than only slowing down future moisture pickup the way a drybox does.

Composites: Carbon Fiber, Wood, and Metal-Filled

Composite filaments add a filler to a PLA, PETG, nylon, or PC base: carbon fiber for stiffness, wood or metal particles mostly for looks. Polymaker's technical data sheet for its carbon-fiber-filled filaments calls for a hardened nozzle, since the filler is abrasive to standard brass.

The stiffness boost from carbon fiber does not automatically make a part stronger in every direction: base material, print orientation, and infill matter just as much. A realistic startup budget should also factor in more frequent nozzle replacement if you print abrasive composites regularly, since a worn brass nozzle degrades print quality well before it fails outright.

Sources and limits

• Prusa Knowledge Base — PETG
• Prusa Knowledge Base — Flexible materials (TPU)
• Prusa Knowledge Base — Polyamide (Nylon)
• Prusa Knowledge Base — Water-soluble (PVA/BVOH)
• Prusa Knowledge Base — Enclosure guidepost
• Polymaker Wiki — Fiberon PA6-CF20 technical data sheet
• Prusa Knowledge Base — Glossary: 1.75 mm
• Prusa Knowledge Base — Prusa USS Drybox

We organize manufacturer and community documentation; we have not measured these products ourselves. The manual for your exact model takes precedence over general guidance.