Yarn Structure :
THe following three main characteristics of a yarn:
1. It is a linear assembly of fibers. The assembly can be of any thickness
2. Fibers are usually held together by twisting. However, some other means of inter-fiber coordination can be used.
3. Yarn fibers tend to lie parallel along the twist spiral (helix). The most important aspect of yarn formation is its visual appearance, which is determined by the peripheral layer of yarn fibers. The second aspect of yarn is its internal structure. The texture of yarn is usually very variable. The differences are partly intentional, caused by the purpose of the yarn, but for the most part they are predetermined by the methods of yarn production available. The way in which the fibers are packed together in the cross section of the yarn is important for the effect of frictional contact between the fibers on the properties of the yarn. If the fibers are loosely packed so that they can move in the interstitial space, the yarn will see fibers with larger and larger diameters if they are more closely packed. Hence two types of packing have been hypothesized and proposed: close packing is packing which gives a hexagonal arrangement of fibers in the cross section of the yarn and open packing is packing type where the fibers are assumed to be arranged in concentric circles. increasing radius. The basic helix model assumes an open packing configuration.
For example, it is difficult to produce yarns with characteristics similar to ring-spun yarns through new spinning processes, and ring-spun yarns still represent the standard reference for comparison with other types of yarns (Table 1.2) (Lord, 2003).
Yarn structure is primarily determined by raw material properties, spinning process and parameters, spinning unit conditions, machine parameters and settings, and twist level, etc. Yarn structure can be open or closed; heavy or compact; smooth, rough or hairy; soft or hard; round or flat; Thin or thick, and so on. In addition to appearance, yarn structure also affects the following yarn and therefore fabric properties: handle; Energy diffusion insulating capacity; Covering capacity; Ability to resist wear, damage, strain, and so on; Abrasion resistance; Pigmentation; Tendency of fibers to bunch longitudinally; and wearing comfort, and so on (Lawrence, 2003).
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