This series, presented by the Bidco International Spinning Industry website, aims to simplify the sciences and techniques of the spinning industry and provide valuable knowledge information in the field, but in a simplified manner so that everyone can benefit from it, especially with the weakness and severe deficiency in providing Arabic academic content, whether through printed paper education or e-learning.
This is due to our belief in the importance of the human role in the development process and in achieving success and progress. The desired development in the field of the spinning industry will not return to its glories except through a conscious and trained workforce, and this is what we will seek to contribute to during a long series that we will present successively in a simplified manner suitable for the worker, the student and the citizen. Also, so that there is some kind of public awareness, at least of some of the techniques of this industry, which is one of the second largest areas of industry in Egypt after the food industries.
Definition of spinning
At the beginning, before we explain how to examine and detect the quality of yarn, we must first present a simplified definition of the concept of spinning. Spinning in the world of the textile industry means (the process of arranging a number of fibers or short filaments in an almost parallel manner, wrapped together around a longitudinal axis to form a thin thread of a certain strength and density. A certain thickness and a certain degree of softness, ultimately forming the yarn or thread. This is the definition of yarn in a simplified way to clarify the meaning.
The effect of the spinning process on its quality
The yarn is characterized by a relatively constant quality, meaning that the quality of the yarn in all its parts is approximately the same. This occurs only when the yarn consists of fibers and filaments that are similar in length and similar in structure and properties to a large extent.The quality is also affected by the purity of the cotton used. The quality of the yarn also depends on the duration of the efficiency of the ginning, flocculation, and purification of the cotton from all its impurities, based on the intervention of gravity and the use of the centrifugal process to separate the impurities from the pure cotton.
Why do we need to test and measure yarn quality ?
Because basically the goal of the yarn industry is to make textiles, and because just as cotton, for example, is the primary raw material for the yarn industry, yarn is the secondary raw material for the textile industry. Just as the quality of cotton affects the quality of yarn, the quality of yarn also affects the quality of the fabric and its characteristics vary in a way. Large and noticeable. Hence the importance of testing the quality of yarn and yarn used in textiles such as type, shrinkage rate, softness, twist direction etc.
Indicator for judging yarn quality
There are important elements that must be focused on and measured accurately to judge the quality of the yarn, which are:
1- Fineness,Count,Density
- Yarn fineness refers to the degree of thickness of the yarn. Since it is difficult to measure the diameter and surface size of yarn in practice, we use the number of yarns, that is, the yarn density, to express the thickness of the yarn. Yarn density refers to the mass or weight of raw material per unit length.
- Yarn density affects the appearance, texture, weight and properties of the fabric, so it is necessary to choose a suitable yarn density according to different uses. For example, fabrics used in winter should be heavy, insulated, and made of yarns of medium thickness and mass or yarns of high thickness and mass. Also, clothing in summer requires that it be lightweight, relatively less dense, and made of low-mass yarns.
2 - Twist ( Direction of twist)
Yarn twisting means that in order to make the yarn have some properties such as strength, elasticity, elongation, luster, ductility, etc., it changes the structure of the yarn by making a relative displacement of the cross-section of the yarn so that the original parallel fibers tend to the central axis of the yarn.
This process of winding, twisting, or twisting the yarn is a prerequisite for us to be able to manufacture a spun yarn from short fibers and filaments. In addition, the twisting will lead to changing the density of the yarn, the strength of the yarn, and the shine of the yarn, which affects the structure of the fabric and its properties.
3 - Strength of yarn thread
Yarn strength, also known as yarn fastness, is a reflection of the quality of yarn. The yarn must have a certain strength to ensure the normal operation of the weaving and knitting process. Yarn strength can be measured by an individual yarn strength tester, and the yarn strength index can be divided into two categories: absolute strength and relative strength. Absolute force refers to the force needed by the thread when it is directly pulled to break or break by an external force, also known as breaking force, expressed as CN/tex.
4 - Quality appearance of yarn
The appearance quality of the yarn is tested visually by observing it wrapped on a black board, where the sample is examined in terms of the required requirements and standards, where thin areas in the yarn are visible, as well as defects such as knots and the percentage of hair in the yarn. The visual examination also shows the extent of regular variation in the yarn.
In any case, there is no absolute quality, but the issue is relative, and the meaning of measuring the quality of yarn is not to search for a thread of absolute quality, but rather to test and examine the availability of the requirements required to be met in the thread that is spun for a specific purpose and to manufacture a specific fabric with specific characteristics and a specific purpose of use. In general, there are no absolute good or bad yarns, but rather we look for yarn suitable for the required fabric, in order to achieve the best use, not to create a surplus of quality, but also to meet the basic needs of customers.
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