Yarn Count PDF

Count Yarns come in different sizes. They can be quite thick, or they can be very thin. Since by nature textile yarns are soft and bulky, the ‘thickness’ of a yarn can not be easily measured by yarn diameter. But textile yarns are often sold on a weight basis, so it is natural to express the size...

Count Yarns come in different sizes. They can be quite thick, or they can be very thin. Since by nature textile yarns are soft and bulky, the ‘thickness’ of a yarn can not be easily measured by yarn diameter. But textile yarns are often sold on a weight basis, so it is natural to express the size of a yarn in terms of its weight or mass. Hence, it is expressed in linear density. 1  Count Count or yarn count is a numerical expression which indicates the coarseness or fineness of a yarn. In other words, yarn count is a number indicating the mass per unit length or the length per unit mass of the yarn. There are mainly two systems or ways of yarn count measurement, these are : Indirect System / Fixed weight system ( length per unit mass ) Direct system / Fixed length system ( mass per unit length ) 2 ASTM D1907–01 :Standard Test Method for Linear Density of Yarn (Yarn Number) by the Skein Method  Direct system of yarn count measurement The direct system or fixed length system is the yarn count system where the count of a yarn is calculated by measuring the mass of a fixed / definite length. In this system, the count of yarn is the number of weight units per length unit. Here, the count number indicates the mass per unit length. So, higher the count, coarser the yarn. In direct count system, the length of yarn is fixed and the mass of yarn varies according to its fineness. This system is commonly used for polyester, nylon, silk, acrylic & jute yarn. The following formula is used to calculate yarn count in direct system : N = ( l × W) / L Where, N = yarn count L = the length of the sample W = the weight of the sample l = ” unit of length ” of the system Some of the most commonly used direct systems include : 3 Tex, Denier, DeciTex (dtex) MilliTex (mtex) KilloTex (ktex) Direct system of yarn count measurement 4 Direct system of yarn count measurement Tex : The yarn number or count in Tex system is the weight in grams of 1000 m of yarn. For example, yarn count 30 Tex means that there are 30 grams of yarn per 1000 m or 1 km of that yarn (mass per length). In other words, yarn count 30 Tex means 1000 m of that yarn will weigh 30 gm. Denier : The yarn number or count in Denier system is the weight in grams of 9000 m of yarn. For example, yarn count 30 Denier means that there are 30 grams of yarn per 9000 m or 9 km of that yarn. In other words, yarn count 30 Denier means that 9000 m of that yarn will weigh 30 gm. 5  Direct system of yarn count measurement deciTex (dTex) : The yarn number or count in deciTex system is the weight in grams of 10,000 m of yarn. For example, yarn count 30 deciTex means that there are 30 grams of yarn per 10,000 m or 10 km of that yarn (mass per length). In other words, yarn count 30 dTex means 10,000 m of that yarn will weigh 30 gm. 6  Direct system of yarn count measurement miliTex (mTex) : The yarn number or count in miliTex system is the weight in milligrams of 1000 m of yarn. kiloTex (kTex) : The yarn number or count in kiloTex system is the weight in kilograms of 1000 m of yarn. Count System Name Unit of length Unit of mass Tex 1000 m No. of grams Denier 9000 m No. of grams DeciTex (dTex) 10,000 m / 10 km No. of grams miliTex (mTex) 1000 m No. of miligrams KiloTex (kTex) 1000 m No. of kilograms 7  Indirect System of Yarn Count Measurement The indirect system or fixed weight system is the yarn count system where the count of a yarn is calculated by measuring the length of a fixed / definite mass. In this system, the count of yarn is the number of length units in one weight unit. So, the count number indicates the length per unit mass of the yarn. That is why, higher the count, finer the yarn. In indirect count system, the mass of yarn is fixed and the length of yarn varies according to its fineness. This system is widely used for measuring count of cotton yarns. The following formula is used to calculate yarn count in indirect system : N = (L × w) / ( l × W) Where, N = yarn count L = the length of the sample w = ” unit of weight ” of the system W = the weight of the sample 8 l = ” unit of length ” of the system Indirect System of Yarn Count Measurement 9  Indirect System Some of the most commonly used indirect systems include : English cotton count (Ne) system Metric count (Nm) system Worsted count (NeK) system Woollen count system. 10  Indirect System English cotton count (Ne) : In this system, yarn count is defined as the number of hanks of 840 yards per pound. For example, yarn count 30 Ne means that there are 30 hanks (each hank consisting of 840 yards of yarn) per 1 lb or 1 pound of that yarn (length per mass). In other words, if a yarn has a count of 30 Ne, it means that 30 hanks (of 840 yards) of that yarn will weigh 1 pound. Note : If (30×840) or, 25200 yards of a yarn weigh 1 pound then the yarn count will be 30 Ne 11 Ne count is also expressed with ’s. (e.g. 50’s cotton yarn)  Indirect System Metric Cotton Count (Nm): In Metric cotton count system, yarn count is defined as the number of hanks of 1000 m per 1 kilogram of that yarn. For example, yarn count 30 Nm means that there are 30 hanks of 1000 m per 1 kilogram (kg) of that yarn. In other words, yarn count 30 Nm means 30 hanks (each hank consisting of 1000m) of that yarn will weigh 1 kg. Worsted Count (NeK) : It is defined as the number of hanks of 560 yards per 1 pound of that yarn. For example, yarn count 30 NeK means that there are 30 hanks of 560 yards per one pound (1 lb) of that yarn. In other words, yarn count 30 NeK means 30 hanks (each hank consisting of 560 yards) of that yarn 12 will weigh 1lb.  Indirect System Woollen Count : In this system, yarn count is defined as the number of hanks of 256 yards per pound. For example, woollen yarn count 30 means that there are 30 hanks (of 256 yards) per 1 lb or 1 pound of that yarn. In other words, yarn count 30 Ne means 30 hanks (each hank consisting of 256 yards) of that yarn will weigh 1 pound. Count System Name Unit of length Unit of mass English Cotton Count (Ne) 840 yards 1 pound / 1 lb Metric Count (Nm) 1000 m / 1 km 1 kg Worsted Count (NeK) 560 yards 1 lb Woollen Count 256 yards 1 lb 13  Yarn Diameter The surface characteristics and appearance of a yarn influence the appearance of the product made out of it. For some specific application of a yarn the uniformity of its diameter is also desired for improved process efficiency and product performance. Diameter also affects the cover of woven fabric and stitch length and tightness of knitted fabric. Weft insertion rate of air jet weaving machines are affected by diameter. As yarn is not perfectly circular, diameter measurements have to be made in two perpendicular planes or, even better, at a number of places around circumference. 14  Yarn Conversion Table 15 Textile Testing UPTTI Kanpur Dr M Regar  SEWING THREAD NUMBERING SYSTEM  Sewing thread numbering system is slightly different from the regular yarn numbering systems.  The commonest system and the one used for synthetic and core spun threads is the metric ticket number system.  It depends on the number of plies used to make the sewing threads. 16  METRIC TICKET NUMBER In metric system, the sewing thread is called the metric ticket number. In metric count system, metric ticket number is the three times of the resultant count of the thread. This means 2, 3, 4 or whatever ply or single thread be in the thread, finding out its resultant count and then it is expressed at three times of it. As for example, a thread in Nm 90/2, its resultant count will be 45 and the metric ticket number will be 135 (45×3 = 135) that means the weight of 135 meters length of thread is 3 grams. In metric ticket number system, the number of meters of thread in 3 grams weight is the metric ticket number. The metric number of thread (Nm) The ticket number of thread The metric number of thread 80/2 The ticket number of thread 120 The metric number of thread 80/4 The ticket number of 17 thread 60 The metric number of thread 60/1 The ticket number of thread 180  COTTON TICKET NUMBER SYSTEM Generally, cotton ticket number system is used for cotton sewing thread. For example, cotton count means, the 3/60 Ne thread is 3 plied and each ply is 60 Ne. Cotton ticket number is the 3 times of the resultant count of the cotton thread. The count of cotton thread (Ne) Ticket number of cotton thread The count of cotton thread 2/40 Ticket number of cotton thread 60 The count of cotton thread 3/40 Ticket number of cotton thread 40 The count of cotton thread 4/40 Ticket number of cotton thread 30 The count of cotton thread 2/60 Ticket number of cotton thread 18 90 The count of cotton thread 3/60 Ticket number of cotton thread  Wrap Reel and Balance Method The wrap Reel is used to measure the length of yarn. The yarn is taken by a wheel where circumstance is 1.5 yds. Electric balance is used to determine the weight of cotton yarn. Bobbin carrier Yarn package Yarn tension Handle Wrap Reel Electric balance 19 Hank = (sample Length ÷ Length unit ) × (Weight unit ÷ sample weight)  YARN Staple yarn is a long continuous length of interlocked fibres. Yarn is a long continuous length of interlocked fibres, suitable for use in the production of textiles, sewing, knitting, weaving, embroidery, and rope making. Key elements for fibre to yarn conversion Raw material(Fibre ) Process 20 Textile Testing UPTTI Kanpur Dr M Regar  Function of Twist in Yarn Structure To increase the yarn strength in order to withstand the stress of preparation and fabric manufacture. The main function of twist is to give coherence to the yarn. If the twist is low, the fibres can be made to slide past one another, but if it is large, the increasing tension would break the fibres. 21  TWIST Twist is the spiral arrangement of the fibres around the axis of the yarn. Single yarn is formed by twisting fibres or filaments in one direction. Ply yarn is made by twisting two or more single yarns together, usually by combining singles twisted in one direction with a ply twist in the opposite direction. The twist binds the fibres together and also contributes to the strength of the yarn. The amount of twist inserted in a yarn defines the appearance and the strength of the yarn. The number of twists is referred to as turns per inch. 22  IMPORTANCE OF TWIST The shape of yarn become round. Increase tensile properties of yarn due to twist. The inter-cohesion affinity of fibres increases due to twist and do not open the fibres easily. 23  Different Definitions of Yarn Twist Skinkle: Yarn twist is defined as the spiral deposition of the components of a twist is the measure of the spiral turns given to a yarn in order to hold the constituent fibres or threads together –. Morton (1957). When a strand is twisted the component fibres tend to take on a spiral formation, the geometric perfection of which depends on their original formation. Twist may be defined as the rotation about the yarn axis of any line drawn on the yarn which was originally, before twisting parallel to the yarn axis – Wool Res. Vol. 3. J Text Insti 38, 1947: Twist may also be defined as thread which is usually the result of 24 relative rotation of the two ends.  TYPES OF TWIST on Basis of Nature Real twist: False twist: To insert a real twist into a length of yarn, one When inserting false twist into a length of end of the yarn should be rotated relative to the yarn, both ends of the yarn are clamped, other end, Spun yarns usually have real twist, usually by rollers, and twist is inserted with a which holds the fibres together in the yarn. false twister between the clamping points. 25  TYPES OF TWIST ON BASIS OF TWIST DIRECTION The direction of the twist at each stage of manufacture is indicated by the use of letters S or Z. S-twist: Z-twist: A single yarn has S twist if, when it is held in the yarn has Z twist if the fibres inclined to the the vertical position, the fibres inclined to the axis of yarn conform in the direction of slope axis of the yarn conform in the direction of the to the central portion of the letter Z. slope to the central portion of the letter S. 26  S-TWIST When a twisted yarn is held vertically, the individual filaments are appearing in this case as the diagonal in the letter "S". The same can apply if several yarns have been twisted together: their combined twist can again appear as the diagonal of the letter "S". 27  Z-TWIST When a twisted yarn is held vertically, the individual filaments are appearing in this case as the diagonal in the letter "Z". The same can apply if several yarns have been twisted together: their combined twist can again appear as the diagonal of the letter "Z". 28  AMOUNT OF TWIST The amount of twist is an important factor in finished consumer goods. The Amount of Twist: In B.S. 946: 1952 it is stated that the amount of twist in a thread at each stage of manufacture is denoted by a figure giving the number of turns of twist per unit length at that stage. It affects the characteristics and properties of a yarn including appearance, behaviour and durability. Amount of twist expressed in Twist Per Inch(TPI) Twist Per Meter(TPM) Twist Per Centimeter(TPC) 29  AMOUNT OF TWIST The amount of twist also depends upon the type of the fabric to be woven: Soft twisted yarns: Yarns intended for soft surfaced fabric are given slack twist. Optimum Twist: Yarns intended for smooth surfaced fabrics are given optimum twists. Such twisted yarns contribute strength, smoothness and elasticity. High Twisted: Yarns intended for crepe fabrics are given maximum amount of twists. 30  FACTORS AFFECTING TWIST The twist introduced in the yarn during spinning depends upon a number of factors, such as follows: The count of yarn to be spun. (Fine yarns require more twist than coarser yarns) The fineness of the fibre being spun (quality of fibre) End Use of yarn (yarn meant to be used as warp yarn or weft yarn, knitting yarn, sewing thread or any other yarn.) The softness of the fabric into which the yarn is to be converted 31  TWIST In practice, yarn twist is described using three main parameters: Twist direction Twist factor or twist multiplier Twist level (turns/unit length). 32 Twist for various subsequent process 33