A yarn is characterized by its count, defining its fineness. This can be expressed by different quantities : in metric number Nm (Km/Kg), in Dtex (g/10000m) or in Deniers Dn (g/9000m). It is also characterized by its regularity and its homogeneity, which represent the variation of the count along the longitudinal axis measured in cN/Tex (centi Newton / Tex) as well as its direction and coefficent of torsion.See the different units of measurement
Types of spinning
- Fibers preparation : Remove impurities from natural fibers.
- Homogeneization : Organize the flock (cluster of fibers) to obtain a regular batt.
- Carding : Remove the last impurities, untangle and align the fibers to obtain a web or a silver.
- Combing : To increase the quality of the product by eliminating the short fibers and paralleling the remaining fibers. This step is not mandatory.
- Gills : Refine and homogenize, also used for fiber mix. Step to be repeated several times. Allows to obtain a ribbon.
- Flyer frame or rubbing frame : Obtain a twisted roving with the flyer frame, and a flat roving ith a false twist in the case of rubbing frame.
- Ring spinning : Obtaining the yarn by drawing, twisting roving and drafting (winding the yarn obtained on coil).
- Open-end : The fibers of the roving are released and then twisted directly. It is the speed of rotation that induces a centrifugal force, which allows to form the yarn. This technique allows a higher yield anda lower production cost, for a breaking resistance reduced by about 30%.
- Self-twisting : Two roving passed between rubbers that will alternately create right to left movements. This system makes it possible to form S.twists and Z-twists.
- Air jet spinning : A silver is subjected to a jet of compressed air that will cause silver to become thinner and more twisted. It is a technique that allows a high yield and low cost for a less solid yarn and more limited in the choice of the count.
Once the yarns have been obtained, they can be wound together in different ways in order to provide new technical or aesthetic properties.
- Multifilament : Yarn composed of several filaments with or without twist.
- Plied yarn : Two yarns twisted together (S or Z).
- Cabled yarn : Twisting of several yarns with at least one plied yarn.
- Assembled yarn : Apposition of single, plied or cabled cord yarns without twisting.
- Textured yarn : Crimp or corrugated filaments assembled.
- Fancy yarn : Creation of a yarn with a different esthetic by varying the spinning process, for example by different yarn tensions or thicknesses.
- Covered yarn : Composed by a core yarn on which another yarn is wound to cover it. This technique is used in particular for elastane yarns to preserve their elastic properties, but also in the case of the use of fragile ceramic or carbon yarns for example.