What does it mean that a fibre is 1K, 3K, 6K, 12K...?

The carbon fibre, es uno de los materiales más ligeros a la par que resistentes que existen en la actualidad, y se compone por filamentos de diámetros mucho menores incluso que el cabello humano (entre 5 y 10 micrones). El principal precursor de la fibra de carbono es una fibra polimérica dominada PAN (poliacrilonitrilo), aunque también hay otras fibras de carbono llamadas fibras pitch, que derivan del alquillán de ulla o de las breas.

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.