A textile yarn is a continuous strand of substantial length and relatively small cross-section composed of staple fibers or filaments suitable for weaving, knitting, or other form of fabric making process. In staple yarns the fibers are twisted while in filaments yarn the filaments may or may not be twisted. The fineness or thickness of a yarn is known as a count of yarn. It is also called the linear density of the yarn. The count of yarn is expressed in the form of numerical numbers. Different systems are used in the different regions of the world to express the count of the yarn (linear density of yarn). There are mainly two systems to measure yarn count. Indirect system and direct system. The indirect system measures the length per unit weight of yarn while the direct system measures weight per unit length of a yarn. The two systems are explained briefly as under.
1). Indirect System
Indirect system measures yarn count as length per unit weight of yarn. Where length is taken in hanks and weight is taken in lbs. 1hank = 840 yards. In this system the weight is fixed while length is vaiable. For example, A count of 40 Ne means that there are 40*840yards = 40hanks of yarn length in one lbs of yarn. Hank is a standard length unit and 1Hank is equal to 840yards. Likewise a 30Ne would have 30hanks or 30*840yards of length in one lbs weight. Thus higher the count, finer the yarn. The system is generally used for cotton, worsted, linen yarns etc.
For ease of calculation the indirect system uses following formula:
Ne = 0.54 * (L/W)
Where, N is the yarn count, 0.54 is a constant, L is the length of yarn in yards, W is the weight of yarn in grams. This system is also called English Count system or cotton count system and mostly used for cotton yarns and can also be written as (Ne).
Commonly used Indirect yarn count systems:
English system: It is defined as the number of hanks (840 yds) per pound. Metric system: It is defined as the number of hanks (1000m) per kg.
Worsted system: It is defined as the number of hanks (540yds) per pound.
2). Direct system
Direct system measures yarn count as weight per unit length of yarn. Where weight is taken in grams and length is taken in kilometers. So it is the number of grams per one kilometer of yarn and is written as “Tex”. For example, A count of 40Tex means that there are 40 grams of yarn weight in one kilometer length of yarn. Likewise a 30Tex would have 30 grams weight in one kilometer length. In this system higher the count, coarser is the yarn. This system is generally used for synthetic fibre, jute and silk, etc.
The direct system uses following formula:
Tex = (W/L)
Where, Tex is the yarn count, W is the weight of yarn in grams, L is the length of yarn in kilometers.
Commonly used Direct yarn count systems:
Tex system or Lea count: It is defined as the weight in grams of 1000 m.
Denier: The number or, count in the denier system is the weight in grams of 9000 m.
Pounds per spindle (Jute system): Count in the pound per spindle system is the weight in pounds of 14400 yards of yarn.