The carbon fibre, is one of the lightest and strongest materials, and is made up by filaments with diameters even smaller than a human hair (between 5 and 10 microns). The main carbon fibre precursor is a polymeric fibre also knowed as PAN (polyacrylonitrile), although there are also other carbon fibres called pitch fibres, which are derived from ulla alkylan or pitches.
The polyacrylonitrile filaments are subjected to a chemical/thermal treatments (oxidation/carbonisation) and stretching process, in which all the non-carbon atoms are eliminated by subjecting them to very high temperatures (between 1000 and 3000 ºC). The result and level of these treatments will determine the characteristics and, above all, the the fabrics resistance that will be made later.
Once these treatments have been completed, the fibres are arranged in groups called "tows".
The carbon fibre strands or tows are distinguished by the number of individual filaments that make them up.
These weaves are commonly defined as 1K, 3K, 6K, 12K, 24K and 50K.
To explain it more clearly, when we say that a twill weave is 3K, it mean that in each of these strands, there are 3000 individual fibre filaments with the same diameter.