Yarn processing includes the following techniques:
Twisting refers to either turning a single yarn around its own axis, in order to enhance its strength or to prevent the single filaments in a yarn from falling apart. Twisting can also mean to twist two or multiple yarns together, with the result of one bigger yarn. Depending on the number of yarns that are twisted together (also called plying), the final yarn, colloquially sometimes referred to as cord, is either 2-plied (meaning two yarns have been twisted together), 3-plied (meaning three yarns have been twisted together) and so on.
Important with twisting are the direction of the twist (S or Z) as well as the number of turns per meter (tpm) the yarn is twisted (in the United States: turn per inches, abbreviated tpi). A single yarn with a twist of 120tpm therefore is turned around its own axis 120 times per meter.
- covering / winding
Covering yarn, or covered yarn, simply refers to a base yarn being covered with another yarn. Covering can be done by many different possibilities, like air blowing or entwining.
Winding on the other hand refers to the process when a yarn is wound onto a yarn carrier, such as a bobbin, a cops, etc.
Braiding is another kind of 3D-surface creation. Compared to twists, braids have a closed surface, which serves as an additional protection of abrasion or so. With braiding, a multiple of yarns are taken and braided together.
- chenille process
Chenille yarn is manufactured by placing short lengths of yarn, called the "pile", between two "core yarns" and then twisting the yarn together. The edges of these piles then stand at right angles to the yarn’s core, giving chenille both its softness and its characteristic look. Chenille will look different in one direction compared to another, as the fibers catch the light differently. Chenille can appear iridescent without actually using iridescent fibers. The yarn is commonly manufactured from cotton, but can also be made using acrylic, rayon and olefin.
- embroidery (Schiffli & multiple head)
Embroidery yarns need to combine fineness with strength in order to be processable as well as to not ruin the appearance of an embroidery dessin. Therefore, usually two single yarns are plied together with a high tpm, to grant the required properties. The yarn can then be used in embroidery - on a Schiffli embroidery machine or on a multiple head embroidery machine.
- sewing thread
While sewing, stress is put on a yarn - even more than with embroidery. It is thus important to strengthen the single yarns by plying them together so that while sewing, the thread will not break. Conventionally, sewing yarns consist of an uneven number of yarns plied together, enabling the final yarn to be used in sewing.