measuring Cotton Count using Wrap Reel

1. Introduction

Fiber

It is defined as one of the delicate, hair portions of the tissues of a plant or animal or other substances that are very small in diameter in relation to their length. A fiber is a material which is several hundred times as long as it's thick.

Textile fiber has some characteristics which differ between fibers to Textile fiber. Textile fiber can be spun into a yarn or made into a fabric by various methods including weaving, knitting and braiding, felting, and twisting. The essential requirements for fibers to be spun into yarn include a length of at least 5 millimeters, flexibility, cohesiveness, and sufficient strength. Other important properties include elasticity, fineness, uniformity, durability, and luster.                

Yarn

Yarn is a generatic term of continuous stand of textile fiber which is suitable for making fabric. Yarns play a vital role in the fabric manufacturing process. Yarn is a product of substantial length and relatively small cross-section consisting of fibers or filaments with or without twist. It is the long fine structures capable of being assembled or interlaced into such textile products as woven and knitted fabrics, braids, ropes, and cords.                                                                 

Count

Count is the numerical expression which expresses coarseness or fineness of yarn. It means that, the yarn count refers how much a yarn is fine or course. We also can say that the yarn count number indicates the length of yarn in relation to the weight.

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

But according to the Textile Institute, they define yarn count as "Count, a number indicating the mass per unit length or length per unit mass of a yarn".
Yarn count is also known as yarn number or linear density.                                                   

2. Objectives

1. To know about yarn count.
2. To know about wrap reel & analytical balance.
3. To know how to determine the count by wrap reel & analytical balance 

3. Apparatus

1. Yarn
2. Wrap reel
3. Analytical Balance

4. Description

Wrap Reel

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.

The lea or lay was a British unit of length.

The Oxford English Dictionary describes it as a measure "of varying quantity" and cites quotations from within various areas of the textile industry which define it as "80 yards". Each lay contains 200 yards. It had a fixed value of 360 feet.                                                  

The tension of the yarn as it was wound onto the reel was important because it would be elastic and so a standard tension was required to ensure uniformity. For a given reel, this would be determined by the friction of the setup and so the test hanks would be made and measured in other ways to calibrate the device.                                                                                   

Fig: Wrap Reel

Wrap reel are two types on the basis of driving method:

<![if !supportLists]>1.      <![endif]>Hand Drive

<![if !supportLists]>2.      <![endif]>Power Drive

Analytical Balance

An analytical balance is a class of balance designed to measure small mass in the sub-milligram range. The measuring pan of an analytical balance 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. Also, the sample must be at room temperature to prevent natural convection from forming air currents inside the enclosure from causing an error in reading. Single pan mechanical substitution balance maintains consistent response throughout the useful capacity is achieved by maintaining a constant load on the balance beam, thus the fulcrum, by subtracting mass on the same side of the beam to which the sample is added.

 

                                                            Fig: Analytical Balance

Electronic analytical scales measure the force needed to counter the mass being measured rather than using actual masses. As such they must have calibration adjustments made to compensate for gravitational differences. They use an electromagnet to generate a force to counter the sample being measured and outputs the result by measuring the force needed to achieve balance. Such measurement device is called electromagnetic force restoration sensor.                               

5. Working Procedure

• Make lea by Wrap reel.
• Weight the lee by analytic balance.
• Convert the weight gram to pound.
• Then the data are put in the count equation
• Then calculated the count by the equation.
• Finally average count are calculated which is cotton count of this sample

6. Experimental Data

Serial No	Length of Yarn	Measured Weight	Calculated Count
1	120 yd	0.0036 lb	39.68

7. Calculation

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

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

= 39.68

8. Result

 
The cotton count is 39.68