Calculation of Warp and Weft Count of a Fabric

Calculation of warp and weft count of a fabric Count is a numerical value, which express the coarseness or fineness (diameter) of the yarn and also indicate the relationship between length and weight (the mass per unit length or the length per unit mass) of that yarn. Therefore, the concept of yarn count has been introduced which specifies a certain ratio of length to weight. The fineness of the yarn is usually expressed in terms of its linear density or count. There are a number of systems and units for expressing yarn fineness. Types of Yarn Count: 1. Direct Count System 2. Indirect Count System 1. Direct Count System: The weight of a fixed length of yarn is determined. The weight per unit length is the yarn count! The common features of aII direct count systems are the length of yarn is fixed and the weight of yarn varies according to its fineness. The following formula is used to calculate the yarn count: N= (W×l) / L Where, N =Yarn count or numbering system W =Weight of the sample at the official regain in the unit of the system L=Length of the sample l=Unit of length of the sample 2. Indirect Count System: The length of a fixed weight of yarn is measured. The length per unit weight is the yarn count. The common features of all indirect count systems are the weight of yarn is fixed and the Length of yarn varies according to its fineness. The following formula is used to calculate they are count: N = (L×w) / W×l Where, N =Yarn count or numbering system W =Weight of the sample at the official regain in the unit of the system L=Length of the sample

l=Unit of length of the sample w = Unit of weight of the sample.

Beasley Balance It is used to directly read the count when the sample size is small. Irrespective of the system of count, two basic requirements for determining count are an accurate determination of sample length and an accurate determination of its weight. The method of determination of count depends to a large extent on the form in which the yarn is available for testing. When yarn is in the form of a bobbin a known sample length can be taken by forming a skein on a wrap reel and suspending it on the hook of a quadrant balance. The count is then read directly from the quadrant scale. When the warp and the weft count of yarn in from a small piece of fabric is required, it is cut into small length with a template. Yarns are then removed from the specimen and the total number of yarn lengths which are required to balance a standard weight on the beam directly gives the count of yarn. This measurement is carried out with the help of a Beasley Balance. Beesley Balance

Beasley Balance consists of a light weight beam pivoted on jewel bearings with a hook at one and a pointer at the other. The beam is initially leveled to bring the pointer against a datum line. A standard weight is suspended in a notch on the beam arm on the pointer side. A template is used to cut short lengths of yarn, the length depending upon the count system required. These short lengths are placed on the hook until the pointer comes against the datum line. The number of short lengths required to balance the beam gives the count of the yarn. A template is provided to give lengths of yarn in Metric, Cotton, Linen, Wool Skein, and

Worsted counts. The balance is housed in a sheet metal box having sliding transparent acrylic doors Scope: It works on the principle of fixed weight and fixed length system. When cotton yarn spun in short length or removed from the fabric, the count can be measured by a special type of balance is called beesleys balance. Principle: The instrument is consist of a simple beam with small hook in one end and a pointer in other end. The beam is initially leveled pointer. A standard weight is hanged on the notch of a beam arm on the pointer side. A template is used to cut short length of yarn. These short length yarns are added on the hook until the pointer is leveled. The yarn count is the number of length of the fiber required to balance the pointer.

Working principle: -

Selection of template, depending on availability of sample

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Yarn is cut by using template and blade

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Cut yarn is hung on the hook until balance of the pointer

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Count the number of yarns

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Repeat the whole process at least ten times and their mean gives the result.

Beesley Balance: Working