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Unformatted text preview: CHAPTER 14- MANUFACTURING YARNS- Spinning— used to describe formation of manufactured fibers by extruding them through spinneret ALSO used to describe formation of yarn from fibers- Drawn— 1) drawing of manufactured fibers to orient molecules within fiber ALSO 2) step in certain processes for creating yarns from staple fibers Making Filament Yarns- Spinnerets used that have exact # of holes ( from 30- several 1000) needed for particular type of yarn- Following extrusion, fibers drawn or alternatively, drawing may take place during subsequent texturing step o Such as with POY polyester- Drawn filament may be twisted together tightly or loosely- *manufactured filament yarns simpler & less expensive to produce*- Spun silk— short silk fibers made into staple yarns- Texturing Filament Yarns o Manufactured yarns treated with processes that use heat setting OR mechanical entangling of fibers to alter bulk, texture, & stretch o Textured to increase bulk for comfort, resiliency, & feel OR to provide stretch to yarn Done by fiber manufacture or @ some later step in manufacture of yarn Steps of drawing & texturing became continuous & now more commonly carried out in simultaneous operation using POY yarns *texturing filament yarns much less expensive than spinning staple yarns o w/ widespread use of POY, texture (who may also be fiber producer) simultaneously draws & textures yarns o Stretch-texturing methods— introduce crimp or curl in fibers that can be pulled out when yarn is stretched; yarn recovers crimp upon relaxation False-twist Stuffer-box Edge-crimping o Air-Jet texturing Textured for bulk & have very little recoverable stretch o Mechanical Methods Only mechanical action used to entangle fibers in yarn Produced primarily through air-jet texturing in which texture produced NOT by heat but by feeding yarns into system in which slack filaments formed into loops by jets of air Resultants have relatively lg. # of randomly spaced & sized loops along filaments or fibers & very little stretch (many fibers retain straight or slightly twisted conformation) ** air-jet texturing used for filament yarns of ANY fiber** o Thermo-mechanical Methods Fibers mechanically deformed under heat have not only increased bulk but greater stretch Fibers twisted, crimped, or curled—subjected to heat to set in modified conformation—then relaxed **only thermoplastic fibers can be durably textured this way** False-Twist Texturing— • Most common method used • Yarn twisted in heated zone & allowed to untwist as it cools—because yarn is moving rather...
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- Fall '08
- Yarn, yarns, plyblended yarns