RESEARCH OF OPERATIONAL PROPERTIES OF THREADED CONNECTIONS OF CLOTHING PARTS

ABSTRACT

This article presents the results of studies of the influence of various technological factors on the slippability in the seams of materials with movable structures. The research of influence of pattern cutting method relative to warp thread and direction of seams in garments on fabric thread slippage along seams in order to select rational design solutions is presented. The dependence between thread extensibility in the seams and plastic deformation of the fabric, allowing for reasonable selection of seam allowance values in the garment, is presented. Results of research into the influence of stitch length and design of joining seams on the value of seam extensibility in garments made of materials with high thread extensibility are also presented. The information obtained about the nature of thread extensibility in the seams will scientifically substantiate recommendations for improving the quality of thread connections in garments depending on the direction of seams and choose a rational design and technological solution. The article presents the results of research for Uzbek abr cloth adras.

АННОТАЦИЯ

В данной статье представлены результаты исследований влияния различных технологических факторов на раздвигаемость в швах из материалов подвижных структур. Представлены исследования влияния способа раскроя деталей относительно нити основы и направления швов в одежде на раздвигаемость нитей ткани вдоль швов с целью выбора рациональных конструктивных решений. Представлена зависимость между раздвижкой нитей в швах и пластической деформацией ткани, позволяющая обоснованно выбирать величины припусков в одежде. Также представлены результаты исследования влияния длины стежков и конструкции соединительных швов на величину раздвигаемости в швах изделий из материалов с высокой раздвигаемостью нитей. Полученная информация о характере раздвигаемости нитей в швах позволит научно обосновать рекомендации по повышению качества ниточных соединений в одежде в зависимости от направления швов и выбрать рациональное конструктивное и технологическое решение. В статье представлены результаты исследований для узбекской абровой ткани адрас. 

Keywords: seam extensibility, fabric density, relative elongation of sample, connecting seam, cutting direction, base, weft, stitch frequency, stitch length, stitch design, stitch strength, abr cloth.

Ключевые слова: растяжимость шва, плотность ткани, относительное удлинение образца, соединительный шов, направление резки, основание, уток, частота стежков, длина стежка, дизайн стежка, прочность стежка, абровая ткань.

In the manufacture of garments, knowledge of the properties of materials necessary for the right choice of product design, its features, means of shaping and shaping, technological techniques and methods of processing various parts and components of the garment, as well as to ensure the quality of products during operation. Properties of materials depend on the types of fibers, weave, raw materials, methods of production and finishing, so it is necessary to study the structure, chemical composition and properties of textile fibers [1].

Thread slippability in seams is one of the technological properties of materials. The aim of the study is to investigate the process of slippability in various textile materials, as well as to study the influence of various factors on slippability in seams. It is known that slippage occurs in low density fabrics of weakly fixed structure. Here, the nature of the fiber should also be considered. For example, viscose, silk, polyacrylonitrile fibers have a smooth surface and are easy to shift.

The fiber composition of the fabric affects sliding.  Sliding occurs in fabrics made from smooth yarns and in fabrics with different densities of warp and weft yarns. For example, in abr cloths, the weft yarns are several times thicker than the warp yarns. Thus, in cotton-silk abr cloths, the filling threads remain unbent, and the smooth warp threads bend around them. This increases the warp's slippage relative to the weft.

Studies carried out by scientists of materials science [2-6] have shown that slippability of threads in seams depends on the structural characteristics of fabrics: weave, surface density of fabric, linear density of threads, fabric density on warp and weft, fiber composition, the number of overlaps per 1cm². Minimum values of sliding ratio are characteristic of plain weave fabrics, and maximum values are typical of twill weave fabrics. Fabrics of equal density are less subject to thread slippage at the seams, compared to fabrics with different warp and weft densities. Increasing the density of the fabrics results in increased curvature of the yarns, making it more difficult for them to move in the warp or weft direction.

The strength in the different directions is not the same. When force is applied at an angle to the warp and weft yarns, the strength of the fabric is less than in the longitudinal and transverse directions. This is explained by the fact that when tensile samples cut at an angle to the warp and weft yarns, only part of the threads of the sample are clamped in the vise of the tensile machine. Moreover, the strength of even this part of the threads, fixed by both ends, is not fully used, since they are situated at a certain angle to the acting force [7].  

Textile materials of different purposes, fiber composition, weave, and surface density were selected for research. They were divided into six groups. They are abr, suit and coat, lining, jacquard, dress and shirt, and furniture and decorative fabrics. This article presents the results of research for adras-type abrasive materials [8].

The influence of cutting direction on the indicator of thread slippage in seams was investigated. Samples were prepared from selected materials, cut at different angles to the warp thread (15⁰, 30⁰, 45⁰, 60⁰, 75⁰ and 90⁰). These angles were chosen because they are characteristic of the direction of the seams in the garment. The slidability of the threads in the seams at these angles to the warp thread was studied according to the method of Kostroma State Technological University [9].

The sample in the chosen direction was subjected to stretching along the cylindrical surface and measured the slippage in the seams along the studied direction (1_α), as well as the change in linear dimensions of the sample (ε_α) between the control marks. The magnitude of the load is equal to operational (9 daN), loading time 30 min. Time of loading of samples of 30 min. was chosen experimentally and is sufficient for reaching the equilibrium state. Increase of test time from 30 to 60 min does not lead to increase of threads extendibility values in seams.

Table 1.

Influence of cutting direction on thread separation in seams (ℓ_α) and change in linear dimensions (ε_α) of abr cloths

The research assesses the amount of thread separation in the seams by the displacement of the threads in the seams. Fig. 1 shows the results of the study of the dependence of slippage in the seams of abr cloths on the direction of cutting relative to the warp thread.

а)

b)

Figure 1. Dependence of slippage l_α and relative elongation ε_α on angle α of fabric cutting, where (a) adras cotton with a surface density of 166 g/m²; (b) cotton-silk adras with a surface density of 137,8 g/m²

For adras fabrics, the lowest slippage is when cutting at an angle of 45° to the warp threads. At 15° and 30° cutting, the slippage rate is insignificant. For cotton-silk adras, the smallest spread occurs when cutting 15^o to the warp thread. Relative elongation is inversely proportional to slippability. The lower the extensibility, the higher the relative elongation.

 In the study, simultaneously with the value of extensibility of the threads in the seams, the presence of plastic deformation of the samples was observed. An inverse relationship was observed between the extensibility and the value of plastic deformation. For samples with minimal sliding, the greatest plastic deformation was observed compared to those with maximum sliding [8,10]. For all fabrics, the greatest plastic deformation is characteristic in the 45^O direction to the warp threads, the least plastic deformation is observed in the direction of warp and weft threads. Applying force along an oblique line changes the angles between warp and weft yarns in the fabric system, which causes a change in the linear dimensions of the fabric. With a change in net angles, warp and weft yarns are more densely arranged, making it more difficult for them to shift relative to each other [8,10]. 

Prediction of the ability of materials to extend at seams in different directions of cutting provides information about changes in linear dimensions of materials when extensibility at seams occurs, as well as the possibility to choose a rational number and arrangement of design lines in garments with minimal or no extensibility of threads at seams. Consequently, when cutting, it is necessary to take into account the ability of fabrics to move the threads in the seams, especially those subjected to repeated stretching, and strive to ensure that the moving threads are located at a certain angle to the cut [8,10].

Thus, evaluation of the values of seam extensibility has shown that the method of pattern cutting relative to the warp thread has a significant impact on the extensibility of threads in the seams. The results of research on the dependence of thread extensibility in seams on the angle of cutting allow us to scientifically substantiate recommendations for improving the quality of thread connections in garments depending on the direction of seams and select a rational design solution. On the basis of the above, we have developed rational variants of garment partitioning for fabrics with high slippage (Fig. 2) [8].

Figure 2. Recommended cutting direction for garment parts made of fabrics with high slidability in the seams

Further, the influence of stitch frequency on slippability of threads in seams of researched materials was investigated. Thus, in the manufacture of products of the upper range of products recommended stitch length for static seams 2,5 cm, for finishing 3-3,5 cm. If the seam falls on a heavy load, it is recommended to increase the frequency of stitching of 1 cm, i.e., use a stitch length of 1,5-2,0 cm. In this regard, to determine the effect of stitch frequency on the extensibility of the threads in the seam, samples were sewn with stitches of length 1,5; 2,5 and 3,5 mm. Tests were carried out on a cylindrical crossbar, covered with leather at a static load of 9 daN according to the methodology.

The results of the study of the effect of stitch frequency on the slippage of the threads in the seams (Fig. 3), showed that for all tested materials, reducing the stitch length of the thread stitch reduces the slippage of the threads in the seams. If the stitch length is increased from 1,5 mm to 2,5 mm, the slippage is increased by 30% on average, and if the stitch length is increased to 3,5 mm, the slippage is increased to 70%. That is, the higher the stitch frequency in 1 cm, the lower the extensibility of the stitches. Seam extensibility with a stitch length of 3,5 mm is 1,5 to 2 times higher than seam extensibility with a stitch length of 1,5 mm. Consequently, for fabrics with high slidability it is necessary to increase the stitch frequency of 1 cm. 

Figure 3. Dependence of fabric threads slippage lα on stitch length (frequency) for abr cloth

In the manufacture of garments, stitches of various designs are used. These are join stitches, edge stitches and finishing stitches. The load falls mainly on the connection stitches that connect the side, shoulder, middle sections and relief sections of products. These seams can be stitched in a blow-out or blow-in, sewn, stretching [12, 13].

In order to determine whether the stitch design affects slackness in thread seams, research was conducted. For selected samples of materials, studies were conducted to determine the effect of thread joint design on the slidability of the threads in the seams. Reinforced lavsan sewing threads №33ll were used as a binding element. The studies were conducted on a cylindrical crossbar with a radius of 4 cm, covered with leather. Presents the types and design of joints used in the research on the effect of joint design on extensibility in joints (Table 2).

Table 2.

Design of thread connection sutures for the studied samples

Figure 4. Diagram of dependence of thread slippage in seams l_α on the design of the seams for abrasive fabrics

As shown by the results of the sample study, the slippage of the threads in the seams also depends on the seam design (Fig. 4). Thus, the greatest resistance to sliding in all fabrics is observed when using a split seam, where seam allowances are fixed with additional stitches at a distance of 2 mm. In this case, the strength of the seam to sliding is due to the fact that in this variation of the design provides for fixing the structure of the fabric on both sides by additional stitches.

The greatest sliding of fabric threads in the seams are observed in samples where a seam is applied in a seam with overstitching and backstitching. This is due to the fact that the seam and the fabric structure are not fixed. In the case of the adjustable stitches, the sliding motion is greatly reduced, but on the unstitched side it occurs. A complex linen lockstitch construction slightly reduces sliding. It also occurs on the loose side.

Consequently, for fabrics with high slippage, it is more acceptable to use a split seam. For example, for abr cloths, the slippage is reduced by a factor of 17. However, for fabrics of the upper range of fabrics a double seam or a tie stitch is used more often, depending on the model, also tie stitches, i.e. stitches with the highest degree of expansion are used. Consequently, when making garments from fabrics of sparse structures, it is necessary to fix the fabric along the seams to prevent sliding [14, 15].

Based on obtained results on character of threads expansion in seams, recommendations on rational design solution for manufacturing products from fabrics with increased fabrics threads expansion in seams are given.   Thus, evaluation of seam slippability values has shown that the way of pattern cutting relative to warp threads has a significant impact on thread slippability at seams. The information obtained about the nature of thread extensibility at seams makes it possible to scientifically substantiate recommendations for improving the quality of thread connections in garments depending on the direction of seams and select a rational design solution.  For example, for fabrics with high slippability, vertical seams should be avoided if warp threads are moved apart relative to weft, and transverse seams should be avoided if weft threads are moved apart relative to warp. Dependences between sliding threads in seams and plastic deformation of fabric have been revealed, allowing for reasonable selection of seam allowance values in garments. When designing articles of sliding fabrics it is recommended to choose design lines with seam directions at angles of 30⁰, 45⁰ and 60⁰ to warp threads. When cutting, it is necessary to take into account the ability of fabrics to extend the threads in the seams, especially those subjected to repeated stretching, and strive to ensure that the extensible threads are located at a certain angle to the cut. To reduce thread slippage in the seams, the stitching frequency should be increased so that the friction between the fabric threads increases and their ability to shift is reduced.

References:

1. Shustov Y.S. Fundamentals of textile materials science. Textbook.-M.: Moscow State Technical University named after A.N. Kosygin, 2007 -302 p.
2. Smirnova N.A. New and improved methods of evaluating the manufacturability of materials for clothing [Text]: a textbook specialty 280800 and 280900. - Kostroma: Publishing house of KSTU, 2003. - 40 с.
3. Smirnova N.A. Material science in the production of garments from linen: monograph - Kostroma: publishing house of Kostroma State Technological University, 2005. - 151 с.
4. Smirnova N.A. Anisotropy properties of flax fabrics for clothing: a textbook - Kostroma: KSTU RIO, 2005. - 110 с.
5. Smirnova N.A., Panikarova N.B., Khokhlova E.E. Prediction of thread slippage in articles of linen fabrics // Izvestia Vuzov. Technology of textile industry. -2004 г.-№3. -С.128-129
6. Zamyshlyaeva V.V., Smirnova N.A. Prediction of thread slippage in products from flax-cotton fabrics. Technology and quality. 2017 г. № 1(37). С.17-20
7. Buzov BA, Alymenkova ND Materialology in the manufacture of products of light industry (clothing production): a textbook. - M.: "Academy", 2010. - 448 с.
8. Alimukhamedova BG, Tashpulatov SS, Cherunova IV, Kadirov TJ Ensuring strength properties of thread compounds in garments: monograph / - Kursk: Publishing house of JSC "University Book" - 2020 - 96 p.
9. Patent for the invention № 2310846RU G01H33/36. Method of thread wearability anisotropy estimation at seams / Smirnova N.A., Khokhlova E.E., Kolmogorova T.A.// patent holder - Kostroma State Technological University; application: December 29, 2005; publication: November 20, 2007.
10. Tashpulatov S.Sh., Alimukhamedova B.G., Lunina E.I., Cherunova I.V., Makhmudova G.I., Shin I.G. Research of influence of cutting angle on the slippage of abr cloth threads in the connective seams of clothes. // Journal "Izvestia Vuzov.  Technology of the textile industry", Ivanovo, Russia, ¹2 (386), 2020.- P.127-129 (Scopus).
11. Tashpulatov S.Sh., Cherunova I.V., Andreeva E.G., Alimukhamedova B.G., Ganieva G.A. Research and comprehensive assessment of the operational properties of thread connections in the system "adras + polymer composite" // Journal of "Proceedings of Vuzov.  Technology of textile industry", Ivanovo, Russia, № 6 (378), 2018.- C.150-153 (Scopus).
12. Koketkin PP Clothing: technology-technique, processes-quality: Handbook / Koketkin PP - M.: MSUDT, 2001. - 560 с.
13. B.G. Alimukhamedova, S.Sh. Tashpulatov, T.D. Kadirov. Development technology of manufacturing clothes from fabrics with rarefied structures. International Journal of European science review, ISSN 2310-5577, Vienna, Austria, Number 1-2 (2017), January-February, P.182-183.
14. Tashpulatov S.Sh., Andreeva E.G. Theoretical bases of the technology of sewing products. - Tashkent, 2017.
15. Alimukhamedova B.G. Development of ways to ensure the strength properties of thread joints of garments. Dissertation of Doctor of Philosophy (PhD) in technical sciences. 2021 TITLI.