Yarns
Yarn is a long continuous length of interlocked fibres, suitable for use in the production of textiles, sewing, crocheting, knitting, weaving, embroidery, and rope making.
Thread is a type of yarn intended for sewing by hand or machine. Modern manufactured sewing threads may be finished with wax or other lubricants to withstand the stresses involved in sewing. Embroidery threads are yarns specifically designed for hand or machine embroidery.
“A yarn is an assemblage of fibres or filaments having asubstantial length and relatively small cross section, with orwithout twist, being the end product of a spinning andwinding process”

Yarn may be any of the following-

• Number of fibers twisted together
• Number of filaments without twist
• Number of filaments twisted with more/less twist
•Single filament
•One or more strips cut by length of a sheet of material of natural/ synthetic or any polymer

Classification of Yarns

TERMS
Spun yarn is made by twisting or otherwise bonding staple fibres together to make a cohesive thread, or single. Spun yarns may contain a single type of fibre, or be a blend of various types. Combining synthetic fibres (which can have high strength, lustre, and fire retardant qualities) with natural fibres (which have good water absorbency and skin comforting qualities) is very common.
Filament yarn consists of filament fibres (very long continuous fibres) either twisted together or only grouped together. Silk is a natural filament, and synthetic filament yarns are used to produce silk-like effects.
Texturized yarns are made by a process of air texturizing, which combines multiple filament yarns into a yarn with some of the characteristics of spun yarns.
Multifilament Yarn is a filament yarn made from multiple filaments, assembled with or without twist.
Monofilament Yarn consists of only a single continuous filament from man-made source.
Assembled Yarns two or more yarns which are wound side by side on to same package, but without twisting around each other.
Folded or Plied Yarns are yarns made by twisting together. Two or more single (and/or folded) yarns of the same or different types. Ex: 2 Ply (two singles)
Cords or Cabled Yarns are yarns made by twisting together. Two or more ply or folded yarns of the same or different types. Ex: 2,3 Ply Cord

Properties of Spun, Filament and Combination Yarns
100%Spun Yarns: Warmth, Softness, Light Weight Ideal for T-Shirts, Sweaters and Blankets
100%Filament Yarns: Smoother, Finer and Lustrous. Ideal for linings
Combination of spun and filament Yarns: Durable, Easy care, Comfortable, Suitable for more applications.

Structure and Twists of Yarns
S- and Z-twist yarn
Yarns are made up of a number of singles, which are known as plies when grouped together. These singles of yarn are twisted together (plied) in the opposite direction to make a thicker yarn. Depending on the direction of this final twist, the yarn will be known as stwist or ztwist. S-Twist: Spirals run upwardto the left (clock wise) Z-Twist: Spirals run upwardto the right (anti clock wise) Combination of S and Z twist: to produce crepe fabrics.
The purpose of twist is to hold the staple fibers together.
The twist could be used in different ways toembed different qualities to the yarn.
A yarn that is twist balanced will not tend to curl.
The direction of twist is also important for further designing as this can be used well by designers.

Yarn twists parameters:
Amount of twist is designated as TPI –turns per inch, which Affects appearance and durability of the yarns.

Twist factor
The angle of twist is the factor that determines how the yarn will behave. Yarns with a low twist level have a lower angle of twist, and will be relatively soft, bulky yarns. Yarns with higher twist angles will be strong, lean and hard yarns. Over twisted yarns will have very high twist angles; they will be very hard, weaker and snarl easily.

Typical twist factors:
Short staple end use Tex twist factor
Doubling weft 2900-3200
Ring weft 3200-3500
Ring warp 3800-4300
Voile 4900-5300
Crepe 5700-7700
Rotor 3700-4700

Twist Factor
Tan ө = Пd l l= 1/turns per unit length d= /¯yarn tex
Therefore, tan ө = turns per unit length X /¯yarn tex
Turns per unit length = K/ /¯tex
Twist factor = turns per inch / /¯cotton count

Fancy yarns

* Fancy yarns are explorations of the prior said attributes such as * Twist * Bulkiness * Color * Material * Blends and Mixes * Material(conventional/non-conventional)

Varieties

* Boucle * Loop * Gimp * Nep * Chenille * Corkscrew * Core spun

Types and characteristics of yarns

1. Single yarns 2. Ply or folded yarns 3. Doubled yarns or compound yarns 4. Cabled yarns or cords 5. Textured yarns: Stretch yarns, Bulk yarns 6. Novelty yarns: * Slub yarns * Flake yarns * Spiral yarns * Ratine yarns * Boucle, Loop or Curl yarns * Nub, Knop, Knot or Spot yarns * Chinelle yarns

Physical properties and performance characteristics of different yarn types:

Yarn type General yarn properties

Continuous filament yarns Excellent uniformity Excellent strength
Natural Can be very fine
Non-synthetic Fair handle
Synthetic Poor covering power

High bulk yarns Light weight Staple Good covering power
Continuous filament Good loftiness and fulln

Stretch yarns High stetchability
Continuous filament Good handle Covering power
Special end use: * Tyre cord Purely functional * Rubber Designed to satisfy a specific- * Core yarn set of conditions * Cabled * Split film yarn

Novelty yarns: Excellent decorative features * Fancy yarns * Metallic

Colour
Yarn comes in many colors. Yarn may be used undyed, or may be coloured with natural or artificial dyes. Most yarns have a single uniform hue, but there is also a wide selection of variegated yarns: * Heathered or tweed: yarn with flecks of different coloured fiber * Ombre: variegated yarn with light and dark shades of a single hue * Multicolored: variegated yarn with two or more distinct hues (a "parrot colourway" might have green, yellow and red) * Self-striping: yarn dyed with lengths of color that will automatically create stripes in a knitted or crocheted object * Marled: yarn made from strands of different-colored yarn twisted together, sometimes in closely related hues

Measurement
A comparison of yarn weights (thicknesses): the top skein is aran weight, suitable for knitting a thick sweater or hat. The manufacturer's recommended knitting gauge appears on the label: 8 to 10 stitches per inch using size 4.5 to 5.1 mm needles. The bottom skein is sock weight, specifically for knitting socks. Recommended gauge: 5 to 7 stitches per inch, using size 3.6 to 4.2 mm needles. These yarns are manufactured in Japan and have variegated colours in a random-dyed pattern.

Spool of all-purpose sewing thread, close-up shows texture of 2ply, Ztwist, mercerized cotton with polyester core.

Yarn quantities are usually measured by weight in ounces or grams. In the United States, Canada and Europe, balls of yarn for handcrafts are sold by weight.
Common sizes include 25 g, 50 g, and 100 g skeins. Some companies also primarily measure in ounces with common sizes being three-ounce, four-ounce, six-ounce, and eight-ounce skeins. These measurements are taken at a standard temperature and humidity, because yarn can absorb moisture from the air. The actual length of the yarn contained in a ball or skein can vary due to the inherent heaviness of the fibre and the thickness of the strand; for instance, a 50 g skein of lace weight mohair may contain several hundred meters, while a 50 g skein of bulky wool may contain only 60 meters.
There are several thicknesses of yarn, also referred to as weight. This is not to be confused with the measurement and/or weight listed above. The Craft Yarn Council of America is making an effort to promote a standardized industry system for measuring this, numbering the weights from 1 (finest) to 6 (heaviest). Some of the names for the various weights of yarn from finest to thickest are called lace, fingering, sport, double-knit (or DK), worsted, aran (or heavy worsted), bulky, and super-bulky
A more precise measurement of yarn weight, often used by weavers, is wraps per inch (WPI). The yarn is wrapped snugly around a ruler and the number of wraps that fit in an inch are counted.
Labels on yarn for handicrafts often include information on gauge, known in the UK as tension, which is a measurement of how many stitches and rows are produced per inch or per cm on a specified size of knitting needle or crochet hook. The proposed standardization uses a four-by-four inch/ten-by-ten cm knitted or crocheted square, with the resultant number of stitches across and rows high made by the suggested tools on the label to determine the gauge.
Yarn Count
Textile yarns are measured in various units, such as: the denier and Tex (linear mass density of fibres), super S (fineness of wool fiber), worsted count, woolen count, cotton count (or Number English Ne), Number metric (Nm) and yield (the inverse of denier and tex). Yarn is spun thread used for knitting, weaving, or sewing. Thread is a long, thin strand of cotton, nylon, or other fibers used in sewing or weaving. Both yarn and thread are measured in terms of cotton count and yarn density.
Cotton count
Cotton count is another measure of linear density. It is the number of hanks (840 yd. or 770 m) of skein material that weigh 1 pound (0.45 kg). Under this system, the higher the number, the finer the yarn. In the United States cotton counts between 1 and 20 are referred to as coarse counts. A regular single-knit T-shirt can be between 20 and 40 count; fine bed sheets are usually in the range of 40 to 80 count. The number is now widely used in the staple fiber industry.
Yarn length
L/m = 1693 × lm/Nec × m/kg, where l/m is the yarn length in meters, lm/Nec is the English cotton count and m/kg is the yarn weight in kilograms.
English cotton count (Nec) is an indirect counting system, that is, the higher the number the finer the yarn.
Thread: a length of 54 inches (1.4 m) (the circumference of a warp beam)
Bundle: usually 10 pounds (4.5 kg)
Lea: a length of 80 threads or 120 yards (110 m)
Denier: this is an alternative method. It is defined as a number that is equivalent to the weight in grams of 9000 m of a single yarn. 15 denier is finer than 30 denier.
Tex: is the weight in grams of 1 km of yarn.
To convert denier to cotton count: lm/Nec = 5315ρ/den, where lm/Nec is the cotton count and ρ/den is the density in denier.
To convert tex to cotton count: lm/Nec = 590.5ρ/tex, where lm/Nec is the cotton count and ρ/tex is the density in tex.
1 Tex = 19 den
Thread
Thread is a cotton yarn measure, equal to 54 inches (1.4 m).

Yarn density conversion Approximate yarn measurement comparison | Denier | m/g | Tex | Worsted | Cotton | Woolen (run) | Linen (lea) | 50 | 180 | 5.6 | 160 | 106 | 56 | 298 | 75 | 120 | 8.3 | 106 | 72 | 37 | 198 | 100 | 90 | 11.1 | 80 | 53 | 28 | 149 | 150 | 60 | 16.6 | 53 | 35 | 19 | 99 | 200 | 45 | 22.2 | 40 | 27 | 14 | 74 | 300 | 30 | 33.4 | 27 | 18 | 9.3 | 50 | 400 | 22.5 | 44.4 | 20 | 13 | 7.0 | 37 | 500 | 18 | 55.5 | 16 | 11 | 5.6 | 30 | 700 | 12.9 | 77.7 | 11.4 | 7.6 | 4.0 | 2 | 1000 | 9 | 111 | 8.0 | 5.3 | 2.8 | 15 | 1500 | 6 | 166 | 5.3 | 3.5 | 1.9 | 10 | 2000 | 4.5 | 222 | 4.0 | 2.7 | 1.4 | 7 |