Fundamentals of Yarn Spinning Technology: A Student Guide
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41 cards
Question: What is the basic principle of open-end (rotor) spinning for inserting twist into the yarn?
Answer: A free yarn end is introduced into the spinning box; as the spun end emerges into the rotor groove it receives twist from rotor rotation outside the n
Question: How does the draw-off nozzle contribute to twist in rotor-spun yarn?
Answer: The draw-off nozzle imports real twist (Z direction) from rotor rotation and contributes additional false-twist effects in Z and S directions, while a
Question: How is yarn removed and collected in rotor spinning?
Answer: The yarn is continuously taken off by the delivery shaft and pressure roller through the nozzle and draw-off tube, then wound onto a cross-wound packa
Question: List key differences in properties between rotor-spun yarn and ring-spun yarn.
Answer: Rotor-spun yarn has lower tenacity (≈10–20% less), lower tenacity variation, higher elongation, lower mass irregularity, far fewer imperfections, lowe
Question: What structural feature of rotor-spun yarn explains its lower hairiness and rougher surface?
Answer: Rotor-spun yarn has a convoluted structure: core fibres are more twisted while surface fibres are only partially twisted or randomly deposited; some s
Question: Why does rotor-spun yarn typically have lower mean relative tenacity than ring-spun yarn?
Answer: Because fibres in rotor-spun yarn are less straightened, leading to lower utilization of fibre strength in the yarn.
Question: Why does rotor-spun yarn show lower coefficient of variation (CV) of tenacity despite lower mean tenacity?
Answer: Rotor yarn has lower variance in tenacity; although minimum tenacity is similar to ring yarn, the overall variation is reduced, so lower CV is observe
Question: Which end-uses or products are typically made from rotor-spun yarn versus ring-spun yarn?
Answer: Ring-spun yarns: clothing, dresswear, bed linen. Rotor-spun yarns: denim, working clothes, terry towels.
Question: What yarn count range is possible with rotor spinning according to the content?
Answer: Yarn counts higher than 10 tex can be produced (implying coarse counts are feasible).
Question: What is air-jet spinning and what distinguishes it from ring and rotor spinning?
Answer: Air-jet spinning uses airstreams to twist staple fibers. It is intermediate: part of the fiber strand flows continuously (like ring spinning) and part