Carding is a mechanical process that disentangles, cleans and intermixes fibers to produce a continuous web or sliver suitable for subsequent processing. This is achieved by passing the fibers between differentially moving surfaces covered with card clothing. It breaks up locks and unorganised clumps of fibre and then aligns the individual fibres to be parallel with each other.
The word is derived from the Latin carduus meaning teasel, as dried vegetable teasels were first used to comb the raw wool. These ordered fibres can then be passed on to other processes that are specific to the desired end use of the fibre: Cotton, batting, felt, woollen or worsted yarn, etc. Carding can also be used to create blends of different fibres or different colors. When blending, the carding process combines the different fibres into a homogeneous mix. Commercial cards also have rollers and systems designed to remove some vegetable matter contaminants from the wool.
Common to all carders is card clothing. Card clothing made from a sturdy flexible backing in which closely spaced wire pins are embedded. The shape, length, diameter, and spacing of these wire pins is dictated by the card designer and the particular requirements of the application where the card cloth will be used. A later version of the card clothing product developed during the latter half of the nineteenth century and found only on commercial carding machines, whereby a single piece of serrated wire was wrapped around a roller, became known as metallic card clothing.
Carding machines are known as cards. Fibre may be carded by hand for hand spinning.