Yarns are continuous strands of fibers that can be woven or knitted into fabrics. Natural staple fibers usually requires processes such as spinning to make yarns. Silk yarn, extracted from silk cocoon are continuous filament yarns. Most of the synthetic yarns also does not require the additional processes of spinning.
Yarn making from Staple Fibers
Yarn making from staple fibers involves picking (opening, sorting, cleaning, blending), carding and combing (separating and aligning), drawing (re-blending), drafting (drawing into a long strand) and spinning (further drawing and twisting). Silk and synthetic filaments are produced by a less extensive procedure. Current high-production yarn-making operations are performed on integrated machines that perform this entire sequence as one combined operation.
Spinning Synthetic Fibers
The term "spinning" is also used to refer to the extrusion process of making synthetic fibers by forcing a liquid or semi-liquid polymer (or modified polymer, e.g., rayon) through small holes in an extrusion die, called a spinneret, and then cooling, drying or coagulating the resulting filaments. The fibers are then drawn to a greater length to align the molecules. This increases their strength. The monofilament fibers may be used directly as-is, or may be cut into shorter lengths, crimped into irregular shapes and spun with methods similar to those used with natural fibers. These steps are taken to give the synthetic yarns the same feel and appearance as natural yarns when they are made into thread, garments and other textile products.