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Presents the influence of rheological properties of a sewing thread on its dynamical loads in a stitch formation process, or on change of thread strength as a consequence of dynamical loads in the sewing process, respectively. Research work shows the change in thread strength, as a result of the stitch formation process forming dynamic loads of a thread, as a function of rheological properties of a thread.

Reports on the importance of the mechanical properties of sewing thread and its interaction with the sewing process.

Denim fabrics of various weight ranges were sewn with three different compositions of sewing threads ‐ 100 per cent cotton, 100 per cent polyester and corespun thread ‐ with all possible ticket numbers, to examine the interaction of various fabric‐thread combinations. The sewing thread performance in terms of seam efficiency, pucker, slippage and needle cutting index was determined and the results were analysed in the light of the dimensional and mechanical properties of the fabric, thread and seam itself. Corespun threads were found to be most suitable from a seam efficiency point of view. However, other sewing parameters such as pucker, slippage and damage were adversely affected by sewing with corespun threads. Tensile properties of fabrics and threads were found to be the most important factors for sewability. Breaking strength and elongation of the fabric and sewing thread had an excellent correlation with seam efficiency. Cotton threads were found to be most suitable for sewing denim from a seam puckering point of view. On the other hand, polyester threads were more prone to develop seam pucker. Corespun thread was the greatest yarn damager compared to cotton and polyester threads. Fabric cover factor and sewing thread diameter were highly correlated with the needle cutting index.

The purpose of this paper is to define the relationships between the structure of multi-thread fancy yarns and the combination of the rotational speed of the hollow-spindle spinning system and thickness and stiffness of the effect component.

To do so, two groups of fancy yarns were made using stiff and soft effect threads and at six different machine settings.

It was found that the stiff effect thread was suitable to make fancy yarns at low rotational speeds, while the thickness of the effect threads was more important than its stiffness at low number of wraps. Additionally, even when using the same number of wraps and the overfeed ratio, a bouclé yarn, a gimp yarn, a wavy yarn or a loop yarn may results if the thickness and stiffness of the effect thread and the rotational speed were all controlled properly.

This study helps fancy yarn spinners to determine the type of final fancy yarns by controlling the spinning geometry in the first spinning zone.

A study of thread tensions on a lockstitch sewing machine was made, measuring simultaneously both the needle and bobbin thread tensions. Experiments were carried out under specified sewing conditions, whereby needle and bobbin thread tensioner adjustment, sewing speed, number of plies, fabric quality and sewing thread quality were varied in order to investigate the effect of these factors on the needle and bobbin thread tensions. The patterns of the thread tension traces obtained were analysed as well as the effect of these factors on the peak tensions detected on both thread tension traces. Four significant peak tensions on the needle thread tension trace and two significant peak tensions on the bobbin thread tension trace were detected, during a stitch cycle. It was found that no significant variations occurred as far as the timing and shape of the peak tensions were concerned. However, variations were detected in the peak tensions according to the sewing conditions, as expected. From the analysis of the data obtained, multiple regression equations were derived to predict, with a good degree of accuracy, the peak tensions generated, according to the sewing conditions.

In this paper, the contribution of dynamic loading, needle and fabric, and the bobbin thread interaction on the changes in the tensile properties of the needle thread are to be investigated.

Tensile properties of the needle thread have been studied at four sewing stages, namely before being subjected to any loading, after dynamic loading, before bobbin thread interaction and after sewing.

It is observed that bobbin thread interaction plays a dominant role in the reduction of tensile properties except breaking elongation in cotton threads. Dynamic loading is mainly responsible for reduction in the breaking elongation of cotton threads. During sewing, there is an increase in initial modulus due to the dynamic loading, which is more in the case of cotton threads than polyester threads. However, the impact of dynamic loading on tenacity, breaking elongation and breaking energy is greater for coarser cotton thread. The contribution of bobbin thread interaction is more for fine threads as compared to coarse threads.

Since seam strength is dependent on the thread strength, a reduction in thread strength during sewing will lead to lower seam strength than expected. Therefore, in order to minimize the thread strength reduction, it is important to understand the contribution of different machine elements or processes during sewing. During high‐speed sewing, the dynamic and thermal loading are found to be the major causes of strength reduction of needle thread, which can go up to 30‐40 per cent. However, the extent of strength loss at different sewing stages is unknown.

The study will help in engineering sewing threads, designing of sewing machines and selection of process parameters for controlling loss of useful properties of sewing threads.

The purpose of this paper is to analyse the advantages of a new interpretation of the geometric disposition of threads within woven fabric structures, and to develop a method of determining the parameters of threads, with reference to each order of their disposition.

Based on the analysis of the geometrical models proposed by Barker and Midgely, by Pierce and by Novikov, the substantiation of the advantages of a stricter model, offered by the authors, for determining the geometric disposition of threads within single layer woven fabric structures with the help of the tangent function is given. This model allows the substantial expansion of the actual bounds of the interval of the order of the geometric disposition of threads in woven fabric structures to 0.2‐9.8.

The tangent function can approximate the crimp height ratio of the warp threads within the woven fabric structure with accuracy within the limits of geometric disposition angle change from 1° to 89°.

The work has applications in the industrial production of woven fabrics.

This research will allow the design of a woven fabric with practically any ratio of crimp height for the warp and weft threads to effectively achieve the required performance characteristics of the cloth.

This paper extends the knowledge of the geometrical characteristics of woven fabric structure, and proposes intelligent methods of determining the parameters of thread cross‐sections in accordance with the orders of the geometric disposition of threads in woven fabric structure.

Develops a neural network based system for optimum assembly speeds using thread‐forming fasteners.

Uses a three layer neural network to optimise thread forming speeds based on thread diameter and pitch and the total number of thread coils.

The method demonstrates savings in energy and reduction in torque values of 20‐30 per cent.

Provides a method that works even when less experimental data are available.

The method should provide a higher quality and reliability and allow thread‐forming fasteners to be used in new application areas.

Provides an efficient and less labour intensive method for insertion speed optimisation.

The aim of the present study is to consider the influence of the tensile behavior of fabric and sewing thread on the seam appearance.

In this study, the formation of seam puckering on two elastic and normal woven fabrics was explored. In order to prepare samples, various sewing threads were applied. Test specimens were sewn under five different thread tension levels. Then the appearance of samples was evaluated subjectively to determine their seam puckering grade before and after the laundering process.

The obtained outcomes of this study present that although sewing thread tension increment decreases the seam pucker ranking in the similar sewing condition, elastic fabrics have a greater seam pucker grade compared to the normal fabric due to the fabric extension and contraction during sewing and after sewing process, respectively. In addition, the elastic strain of the sewing thread is the key factor that determined sewing thread's tendency to make seam puckering. Moreover, the laundry process due to the relaxation of the sewing thread decreases the seam pucker grade.

The consistency of the tensile property of fabric and sewing thread is a crucial parameter in improving the seam appearance and obtaining a smooth seam.

A prototype system for detecting sewing defects through analysis of thread motion has been developed. A piezo‐electric transducer provides information on the time of motion of the top thread in a lockstitch sewing process. The ratio of this time of motion to the total single sewing cycle time is a measure termed the thread motion ratio. This measure offers consistency over variations in sewing machine speed. Research results are that the system yields reliable indication of thread consumption‐related faults, such as broken top or bobbin threads, misfed fabric, and thread tension imbalance, for several stitch types.