PREDICTING THE STRENGTH CHARACTERISTICS OF COTTON YARN

ABSTRACT

This article describes a computer program for the rapid determination of the R_km index of combed and carded yarns using the HVI values of each type of fiber included in the lot. Using this program makes it possible to easily and quickly select the optimal ratio of raw materials from different grades.

АННОТАЦИЯ

В данной статье приводится описание компьютерной программы для экспрессного определения показателя Rкм гребенной и кардной пряжи с использованием показателей HVI каждого вида волокна входящего в состав сортировки. Использование данной программы дает возможность легко и быстро подобрать оптимальное соотношение сырья из разных сортировок.

Keywords: cotton fiber, yarn, strength, unevenness, spinning, linear density, sorting, lot, quality.

Ключевые слова: хлопковое волокно, пряжа, прочность, неровнота, прядение, линейная плотность, сортировка, лот, качество.

Introduction. High requirements for consumer properties and quality of products of the textile and light industry determine its competitiveness both in the domestic and foreign markets.  The growing demand for the quality of textile products in the world takes into account important factors affecting the processes of technological process in the production of finished products, in connection with which scientific research is carried out. Therefore, more and more attention is being paid to the correct selection of raw materials in the manufacture of finished textiles, while preserving the properties of fibers, as well as the introduction of complex, innovative technologies for the production of high-quality and competitive products [1]. The quality of the products is formed in the process of its production. Rational use of raw materials is one of the most important ways to improve the efficiency of textile enterprises. The cost of raw materials has a significant effect on the cost of yarn, therefore, it is important to determine the share of each component in the mixture, which ensures the minimum cost of raw materials and the required properties of the yarn [2]. Spinning enterprises produce yarn according to market demand, and therefore, the question often arises of the selection of raw materials that meet the requirements of the consumer. Yarn meeting the requirements of the standard was usually produced from several lots. In order to improve the quality and expand the range of textile products, it is necessary to choose the right initial parameters and conditions for processing raw materials, depending on their purpose. The indicators characterizing the quality of the resulting yarn include breaking load and breaking elongation of the yarn, work of breaking, yarn unevenness and a number of other indicators [3].

Theoretical part. Product quality management requires knowledge of properties, the ability to correctly measure and objectively evaluate the most important quality indicators, as well as to reliably predict the quantitative characteristics of product properties. Of the whole variety of properties of textile materials (structural features, geometric, mechanical, physical, chemical, aesthetic, etc.), mechanical properties are of particular importance, since they have a significant impact on the course of technological processes in the processing of textile materials. In addition, the mechanical properties of raw materials largely determine the operational properties of finished products. The most important indicator characterizing the properties of a yarn is breaking load. When predicting the strength of cotton yarn, the R_km – breaking length is used. This indicator is included in the international standard USTER STATISTICS 2018. There is a relationship between the breaking tenacity and the R_km indicator, i.e.

R = R_km · 0.9807 cN / tex. On the recommendation of the South Indian Center for Textile Research (SITRA), Rkm is calculated using the empirical formula:

For a carded spinning system:

 , gf / tex                                (1)

For a combed spinning system

 , gf / tex                 (2)

L - average fiber length, mm;

R - breaking tenacity of the fiber, cN/tex;

M - fiber micronaire index;

N_e - english yarn number;

Y - percentage of the combed noil, %

Despite a significant number of regulatory and technical conditions governing test methods, the existing methods require significant material and time costs and do not allow predicting yarn quality indicators under conditions of their further processing and operation in a product.

Experimental part. To solve this problem, a program was developed for calculating Rkm of carded and combed yarns in the modern object-oriented DELPHI language, which allows you to reduce time and material costs during testing while increasing their information content. The program has a windowed application interface and is easy to use. Using the program, you can easily select the optimal ratio of raw materials from different grades, that is, to calculate R_km, the user must enter the HVI indicators of each type of fiber included in the lot and their quantity, as well as the yarn number to be obtained. The program then calculates the percentage of each type of fiber based on the total volume of used bales and the average values of the parameters of the raw materials (Mic., Length.,STR.) (Tab. 1).

Table 1.

Fiber indicators of the lot

After the program calculates the average values of the raw material parameters, these values are substituted into the formulas for calculating R_km for carded and combed yarns. The obtained values can be compared with the standard values of USTER STATISTICS 2018 [4], given in table 2.

Table 2.

Physical and mechanical indicators of USTER STATISTICS 2018 by quality classes of carded and combed yarns

When entering the English yarn number, the above table appears on the screen. If the obtained values of R_km do not satisfy, a new percentage of different types of raw materials is introduced and R_km is recalculated. Thus, you can find the right combination to create a working lot. The results of calculating R_km of yarn KСM 30 and KCD 30 are shown in Table 3.

Table 3.

The results of calculating R_km of yarn KСM 30 and KCD 30

Conclusion. Thus, a program was developed and tested to select the best content of components in the lot. It can also be used in the selection of raw materials for the production of yarn with specific quality characteristics of a given assortment. This program provides a quick calculation of the strength of yarns made from a fiber mixture of various components and helps to determine the R_km value - the strength of yarns produced by carded and combed spinning systems.

It is important to note that this program is widely recommended for the production of inexpensive, competitive yarns. The developed software product is designed to quickly determine the value of the R_km indicator, which is the main indicator for assessing the quality class of yarn at spinning enterprises when making a lot of cotton fiber.

References:

1. Yusupalieva U.N. Sovershenstvovanie metodov sostavleniya sortirovok iz xlopkovogo volokna dlya virabotki kachestvennoy pryaji, Avtoreferat dissertatsii doktora filosofii (PhD) po texnicheskim naukam. Tashkent, 2020 g. - S. 21.
2. Solovyev A.N., Kryuxin S.M. Otsenka i prognozirovanie kachestva tekstilnix materialov. -M.: Legkaya i pishevaya promishlennost, 1984. - S. 215.
3. Sevostyanov A.G. i dr. Mexanicheskaya texnologiya tekstilnix materialov. Legprombitizdat, 1989. – S. 8.
4. SITRA Norms for Spinning mills, (SITRA, Coimbatore), 2018.