What is Yarn count | Types of Yarn counting system?

Yarn Count

Yarn count is a term used to express the thickness of  yarn. In spinning process, there is a relation between the weight of the original fibres and the length of yarn. This relation is indicated as thickness. Thickness of yarn is determined by the extent of drawing process (varying draft) and designated by number. The number is called count.

So, when we say what is yarn count? The answer will be, yarn count is the weight per unit length or length per unit weight which expresses the fineness or coarseness of yarn.

According to Textile Institute, “Count, a number indicating the mass per unit length or the length per unit mass of yarn.

Types of count system

Basically, two types of yarn counting system:

1. Direct system
2. Indirect system.

Another system is classified as third type of count and that is “Tex”. Tex is also called Universal count. International Organization for Standardization (ISO) fixed the relationship between weight and length for Tex. The greater the weight, the thicker the yarn and Tex will be greater number. We will discuss it under Direct system.

Direct System

In this system, the count of yarn expresses the no of weight units in one length unit. Higher the count, coarser the yarn. This system is generally used for Man made fibre, jute, silk etc.

Now, let’s see the how count is mathematically calculated.

Let,
N = The yarn number or count.
W = The weight of the sample.
w = The unit of weight of the system.
L = The length of the sample.
l = The unit of length of the system.
Now, Count, N = (W×l)/L

Indirect System

In this system, the count of yarn is expresses the no of length unit in one weight unit. Here, when count is higher, then yarn will be finer. The system is usually used for cotton, worsted, metric, french, linen (wet spun) etc.

Let,
N = The yarn number or count.
W = The weight of the sample.
w = The unit of weight of the system.
L = The length of the sample.
l = The unit of length of the system.
Now, Count, N = (L×w)/(l×W)