Lecture 4. Yarns PDF

YARNS www.knust.edu.gh  YARNS Yarn Making The conversion of fibres into yarn is called spinning. Spinning holds the fibres together. Fibers are converted by twisting them together. Twisting is done in a clockwise or anti-clockwise direction....

YARNS www.knust.edu.gh  YARNS Yarn Making The conversion of fibres into yarn is called spinning. Spinning holds the fibres together. Fibers are converted by twisting them together. Twisting is done in a clockwise or anti-clockwise direction. i.e. The “S” or “Y” twist. www.knust.edu.gh YARNS CONT’D www.knust.edu.gh Yarn Wicks Wicks for Diya www.knust.edu.gh  Types of Yarns Single yarn: a group of fibres twisted together Ply yarns: two or more single yarns twisted together Cord: two or more ply yarns twisted together Novelty yarns: produced by twisting or folding www.knust.edu.gh Types of Novelty Yarns www.knust.edu.gh  TYPES OF NOVELTY YARNS CONT’D Nub yarns: the effect yarn is wound over the core yarn in such a way that thick and thin areas are created on the yarn. Boucle’ yarns: they have large loops projecting from their surface at regular or irregular intervals. Chenille yarns: these yarns resemble caterpillar, as tuffs of fibers are inserted uniformly in the yarn twist perpendicular to the yarn. Flock yarns : yarns to which small tuffs of fibers are added at regular intervals and held in placed by the twist. www.knust.edu.gh  TYPES OF NOVELTY YARNS CONT’D Crepe yarns: yarns which have been giving very high twist and they exhibit a grainy feel. Spiral yarns: tow yarns of different colours and twist are plied together in such a manner that the loosely twisted effect yarn is wound on the core yarn which has high twist Sewing threads: sewing thread are special kind yarns. While yarn is bunch of fibers twisted together, a thread is a yarn with high twist; smooth surface and high strength. www.knust.edu.gh TYPES OF NOVELTY YARNS CONT’D Crepe Yarns Highly twisted yarns and a grainy feel. www.knust.edu.gh  Tow Yarns The tow yarns are an untwisted bundle of continuous filaments. www.knust.edu.gh  TYPES OF NOVELTY YARNS CONT’D Ratine yarns : is similar to the boucle yarn , but the loops projecting are held in place by the binder. www.knust.edu.gh  Weaknesses of novelty yarns Novelty yarns are often weak and have poor abrasion resistance. Novelty bulky yarns may make the fabric hard to handle. Fabrics made from novelty yarns are generally not durable as they are susceptible to wear from abrasion. The parts of a novelty yarn exposed beyond the surface of the ground ply are particularly vulnerable to abrasion. These yarns should be avoided for manufacturing those fabrics where durability and long wear is required. www.knust.edu.gh  YARNS CONT’D Topic for next lecture; Fabric Structures www.knust.edu.gh