Determination the yarn count of a given cotton sample.

Experiment  Name: Determination the yarn count of a given cotton sample.

<![     1.0Intriduction:

Yarn is a long continuous length of interlocked fibers, 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.[1]

Yarn Count: 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. [3]

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. But they are classified as follows. 

Types of Yarn Count:

• Direct Count System 
• Indirect Count System

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

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. [3]

  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. 

2.0   Objectives:

   2.1 To know about yarn count.

2.2 To know about wrap reel & analytical balance.

2.3 To know how to determine the count by wrap reel & analytical balance.

3.0 Apparatus:

        3.1 Wrap reel

        3.2 Analytical balance

        3.3 Sample yarn

4.0 Description:

A wrap reel or skein winder is a device for measuring yarn and making it into hanks of a standard size.. The reel is of a standard size and its revolutions are counted as the yarn is wrapped around it. Typically, a set number of revolutions will be used so that the hank is of a standard size — a skein or lea. For example, a skein of cotton would be 80 turns on a reel of 54 inches circumference, making 120 yards, while the standard length for wool worsted would be 80 yards. [2]

An analytical balance (often called a "lab balance") is a class of balance designed to measure small mass in the sub-milligram range. The measuring pan of an analytical balance (0.1 mg or better) is inside a transparent enclosure with doors so that dust does not collect and so any air currents in the room do not affect the balance's operation. This enclosure is often called a draft shield. The use of a mechanically vented balance safety enclosure, which has uniquely designed acrylic airfoils, allows a smooth turbulence-free airflow that prevents balance fluctuation and the measure of mass down to 1 μg without fluctuations or loss of product. [4]

5.0 Working procedure:

• Make lea by Wrap reel.
• Weight the lee by analytic balance.
• Convert the weight gram to pound.
• Now the data are put equation (1)
• Now calculate the count by the equation.
• Now average count are calculating which is cotton count of this sample.

6.0Experimental Data:

Exp. No	Length (yds)	Weight (gm)	Weight (lbs)	Average
01	120	1.633	0.00360	0.0036
02	120	1.631	0.00359
03	120	1.635	0.00360

7.0Calculation:

       Length in yard × Weight Unit
Count = ..........................................................
                   840 Yard × Weight in pound 

           120×1 
=          ......................
            840×0.0036 

=          39.64

8.0 Result:

The cotton count is 39.64

9.0Conclusion:

It's very important to determine the count of a yarn. We have to know and ensure the count of a yarn to produce garments which contains required quality. First of all, yarn attached with wrap reel and wrap the yarn for 80 times which means 120 yards of yarn is collected and measure the weight of yarn. Calculation was completed by using this weight and length. Now we have the exact count of yarn.