Processing Stages.ppt

Processing Stages Preliminary processing Opening, cleaning blending Carding Combing Drawing Roving Spinning Downstream processing Opening - “open” large mass of fibers into tufts Cleaning – remove impurities Blending – mix required proportions of fibers Carding – disentangle fiber tufts into individual fibers; clean; and intimately blend Combing – remove short fibers; clean; and straighten fibers Drawing – reduce count; blend slivers; and straighten fibers Spinning Roving – draft to required count; insert required twist or other technique for imparting strength to yarn Post-Processing - winding, doubling twisting Status of Fiber Assembly Web – sheet of fibers delivered from a card also used for multiple sheets of fibers in nonwovens ; Lap – continuous batt of fibers which can be rolled and transported; Batt – a random arrangement of fibers held together by friction and entanglement Sliver -- a rope-liked coherent assembly of fibers, normally without twist, and typically in the count range 2.5 - 25 ktex. Fiber orientation depends on the stage in processing and usually the sliver may be further described by its previous process e.g. card sliver, breaker sliver, combed sliver, and finisher sliver . Roving -- A lightweight fibrous assembly, produced in the latter stages of yarn manufacture, used as a feed material to the ring spinning frame. Rovings normally have a small amount of twist and are wound onto a bobbin. Yarn Spinning Routes Spinning systems Short staple system - Cotton system carded, combed and “waste” cotton systems Long staple system worsted system, woolen system, semi-worsted system Opening, cleaning, blending Carding Spinning drawing combing woolen roving drawing spinning roving spinning carded cotton combed co worsted Carding * The proportion of fibers collected by a worker is called the collecting power, and is usually expressed as a percentage. Given the same settings between a swift and each of its workers, the collecting p