chapter 7 yarns Flashcards
simply one fiber
monofilament yarn
A yarn made up of a number of filament fibers. All fivers for one yarn are extruded at one time. Usually the number of fivers in yarn ranges from 30 to several thousand.
multifilament yarn
short lengths of finer twisted together
spun yarn
spirals run upward to the left
s twist yarn
continuous strands of fibre many miles long
filament yarn
spirals run upward to the right
z twist yarn
fuzzy, bulkier yarn with uneven diameter and varied finer length
woolen yarn
two or more single yarns twisted together
ply yarn
smooth, twisted, firmer yarn with even diameter
worsted yarn
heated filaments are drawn over an edge, which flattens one side of the filaments and causes the yarn to curl.
knife-edge method
sawtooth crimp is created when yarn passes through the teeth of two heated gears
gear crimping
filament yarns are pushed into one end of a small heated box until they bend
stuffer box method
high velocity air or steam is used to distorted some fibers in a yarn so that they loop or curl
air-jet method
yarn is omitted into a thin tube, heat set, and unravelled
knit-deknit method
What are bulky yarns?
Bulky yarns are created from fibres that, because of their inherent characteristics, cannot be packed closely together. often used in swathers, carpet, upholstery and warm hosiery
What are crimped yarns?
Crimped yarns are usually made of thermoplastic fibres, most commonly by the false-twist method. these yarns may be used when stretch is needed.
What are the three types of textured yarns?
loopy, high bulk, stretch
What are the three types of bulk yarns?
Bulky, crimped, textured
yarns that have irregular spaced loops along their lengths
loopy yarns
What are high-bulk yarns?
yarns that are combinations of manufactured fibres. these yarns do not have much stretch
Yarns that have a high degree of elastic stretch
stretch yarns
The process of creating a cohesive yarn from short fibres
spinning
What are the three major spinning systems?
Cotton, Worsted, Woolen
Yarn formation system used for cotton, silk noil, and short manufactured fibres
Cotton system
Soft, bulky yarns with fibre ends on the surface that are carded but not combed.
Woolen yarns
Yarns that are twisted more tightly and are smoother and stronger than woolen yarns.
Worsted yarns
What is carding?
Many bent wires separate and partially align the fibres to form a thin web. Creates a fuzzier. bulkier surface.
What is combing?
the process of further aligning the fibres. A comblike device removes shorter fibres and makes the remaining fibres more parallel. These yarns are smoother and have fewer fibre ends than carded yarns.
A variation of ring spinning that creates a smoother, stronger yarn by condensing the roving before the final twisting
Compact spinning
Method of spinning yarn from staple fibres. The roving is twisted and wound onto a bobbin in one operation
Ring spinning
What us roving?
The intermediate stage between sliver and yarn. The roving is slightly more cohesive than the sliver.
Method of spinning yarn from staple fibres. Fibres are fed into a rotor, where centrifugal force deposits them in a V-shaped groove. as yarn is pulled out, more fibres are added.
rotor spinning
A variation of ring spinning that eliminates the roving. The sliver goes directly into the spinning frame. The resulting yarn is suitable for pile fabrics and carpet
Direct spinning
Two strands of roving are fed between two rollers that insert twist. Each yarn will have areas of Z twist and areas of S twist. When they are combined, the yarns twist over each other. This process is especially appropriate for combining staple strands, filament strands, or staple and filament strands.
Self twist
What is a simple yarn?
typically made into relatively flat, smooth fabrics
Most fabrics are made of this type of yarn because it is inexpensive to produce
Single yarns
What are ply yarns?
Two or more single yarns twisted together
Cord yarns
two or more plies twisted together
Novelty yarns that are ply yarns in which an effect yarn loops around the core yarn
Boucle yarns
Novelty yarns that are pieces of leno fabric that has been cut into strips
Chenille yarns
