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Glossary · Filament

3D printing

Fibre-reinforced filaments (CF, GF)

Printing materials with carbon or glass fibres mixed in. Parts become stiffer and look matt, but standard nozzles wear out quickly with them.

Explained in more detail

Short carbon (CF) or glass fibres (GF), usually 10 to 25% content, in PLA, PETG, PA or PC. Higher stiffness, less warping, a matte surface; toughness often decreases. The fibres are abrasive and quickly wear down brass nozzles and drive gears, so use hardened steel or carbide nozzles. Often hygroscopic, especially PA-CF.

Where does the term come from?

CF stands for "carbon fiber", GF for "glass fiber". The abbreviations are appended to the base material, for example PLA-CF or PA-GF.

In practice

  • If your printer's data sheet lists only brass or stainless steel as the nozzle material, the nozzle is not intended for CF and GF.
  • A 0.6 mm nozzle clogs less often than a 0.4 mm one; 0.2 mm nozzles are unsuitable.
  • Glass fibre comes in many colours and gives way before breaking, while carbon is stiffer, lighter and almost only dark.
  • You can often gain more strength more easily with more walls than with fibres.
  • When sanding, work wet, wear at least an FFP2 mask and wipe up dust with a damp cloth.

Not to be confused

The chopped short fibres have little in common with continuous carbon, as in a bicycle frame. CF filament is stiffer, but not automatically stronger than the base material.

Frequently asked questions

Is carbon filament stronger than normal filament?

Stiffer yes, stronger not necessarily. Tests show that tensile strength often drops, especially between layers, and that parts break more brittlely.

Which nozzle do I need for CF filament?

A hardened nozzle, for example made of hardened steel or tungsten carbide, or with a ruby tip. As a size, 0.6 mm is often the better choice than 0.4 mm.

Printers that can process Fibre-reinforced filaments

According to manufacturer specifications, from the 15 printers in the wiki: