Search results

In Parts 1 and 2 of this series of papers, we have investigated the important mechanical and physical properties of fabrics which determine their performance during tailoring especially fabric tensile, shear, bending and dimensional properties. The conditions for structural balance of seams has been quantitatively evaluated as well as the relationship between the degree of fabric overfeed during sewing and the natural curvature or curling couple of the seamed fabric assembly. Fabric forming and draping behaviour is strongly dependent on fabric bending and the fabric membrane properties of extension, longitudinal compression and shearing in the fabric plane. In this paper, the influence of these basic fabric mechanical properties on subjectively assessed garment appearance is also studied. These mechanical properties can be used to distinguish between fabrics which make up into suits of good and poor appearance. The investigation of the bending properties of overfed fabrics has established an empirical relationship between the level of fabric overfeed and the natural curvature of the overfed seamed fabric composite for three different fabric configurations.

In Part 1 of this series of papers, we investigated the importance of fabric overfeed in the sewing operations during tailoring. It was also shown how fabric bending rigidity, formability, shear and hygral expansion are important in clothing manufacture. The present paper is concerned with the measurement and experimental study of seam balance, breaking elongation and bending properties of seams. The aim is to evaluate quantitatively the consumption of sewing thread and the relationship between the degree of fabric overfeed during sewing and the curvature of the seam in the garment. Balanced seams have much higher breaking elongation and more symmetrical bending properties than unbalanced seam structures. A natural curvature and curling couple result from fabric overfeed during sewing. The value of the curvature is time‐dependent because of fabric viscoelastic effect and also depends on the level of fabric overfeed, the tensile and longitudinal compressive module of the component fabrics and the structure of the seamed composite. The natural curvature of the seam may be derived quantitatively from the relative lengths of overfeed fabrics using a modified theory for a bimetallic themostatic strip.

The viscoelastic properties of the sewing thread before and after loading in the sewing process were investigated. Sewing threads are subjected to dynamic tension and friction in the sewing process. In order to compare polyester, cotton and silk sewing threads, the fineness of the threads were selected to be almost equal. There are some differences between the stress extension curves of the parent thread and the sewn thread except for the polyester sewing thread. The phenomenon of inverse relaxation occurs for high levels of retraction. The stress‐inverse relaxation index for the polyester sewing thread is larger than for other threads and the inverse relaxation for silk thread is small. From the creep curves, the sewn threads show higher secondary creep and lower instantaneous recovery than the parent threads.

Knitted fabrics have been widely used in a wide range of applications such as apparel industry. Since these fabrics are continuously subjected to the long-term tensile stresses or tensile creep in real conditions, investigation of viscoelastic behavior of sewn knitted fabrics would be important especially at the seamed area. The paper aims to discuss this issue.

A lockstitch machine was used to produce sewn samples by knitted fabric. Factors such as stitch per inch (SPI), thread tension and thread type were variables of the model. Tensile creep tests under constant load of 200 N were conducted, and creep compliance parameter D(t) of samples was obtained as a response variable. A successive residual method (SRM) was also used to characterize viscoelastic properties of sewn-seamed fabrics.

The instantaneous elastic responses of the seamed samples were less than those of the neat fabric (fabric with no seam). An increase in sewing thread strength increases the instantaneous elastic response of the sample. SPI and thread tension have an optimum value to increase E₀. High tenacity polyester thread, due to its higher elastic modulus, caused a larger E₀ than polyester/cotton thread in sewn knitted fabric. Characteristics of seam including sewing thread type, SPI and sewing tension have significant influence on T₀. Sewn-seamed fabric by high modulus thread shows less viscous strain T₀ than the neat fabric (fabric with no seam). Viscous strain T₀ decreases as SPI changes from 8 to 4 and/or 12. SPI and thread tension have an optimum value to increase the viscous strain T₀. E1 is the same for optimum seamed fabric and fabric sample but T1 is about two times greater for seamed fabric. Retarded time for creep recovery increases by sewing process but characteristics of seam have significant influence on E1 and T1. All sewn knitted fabric samples used in this study could be described by Burger’s model, which is a Maxwell model paralleled with a Kelvin one.

This paper is going to use a different method named successive residuals to model the creep behavior of seamed knitted fabric. On the whole, this paper paved a way to obtain viscoelastic constants of sewn-seamed knitted fabrics based on different sewing parameters such as the modulus of elasticity of the sewing thread, SPI and sewing thread tension.

The purpose of this paper is to propose a rational and complete design scheme of seam type of outdoor clothing, so as to improve the seam efficiency and appearance of outdoor clothing, as well as to provide an optimal seam base for the subsequent pressure adhesive process.

Four types of common outdoor fabrics and four seam types were selected. Seam strength and thickness were measured. Seam efficiency and seam thickness strain were calculated to evaluate seam quality. Multiple linear regression analysis was adopted to analyze the influence of seam type essential factors on seam strength.

Among the component factors of seam type, based on two stitches, seam strength was significantly affected by stitch distance, followed by fabric layer on the seam side. The increase of stitch and the interaction among fabrics can effectively improve the seam efficiency. The methods are as follows: the increase of stitches, stitch distance shortening, the increase of fabric layers, etc. The change of seam type had no significant influence on seam thickness strain. A seam-type design scheme of outdoor clothing with good mechanical and appearance properties was designed by choosing the seam types FX₁, FX₂ and FX₄.

This paper designed a practical scheme of seam-type design of outdoor clothing, which has been applied in the industrial production process. It is important for guiding the improvement of seam quality and the production efficiency of outdoor clothing.

Observes that the formability of woven fabric has a major effect on the appearance of garments, in that seams sewn from fabrics with low formability are more likely to pucker than those sewn from fabric with high formability. Describes the concept of formability and illustrates the relationship between this parameter and seam pucker, the difficulty of a particular sewing operation and the appearance of structured jackets. Notes that the formability of wool fabrics is most appropriately controlled in finishing by modifying the extensibility of the fabric. Discusses the difficulties associated with engineering, the extensibility of woven fabrics and the implications for other fabric properties, such as relaxation shrinkage.

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

The paper aims to evaluate the influence of mechanical properties of sewing threads on the seam pucker.

The mechanical properties of sewing thread were obtained performing tensile testing research. The seam pucker of lightweight fabric was evaluated after sewing, then after 24 h, after 48 h as well as after washing and drying. To determine dimension changes of fabric, the relaxation shrinkage was calculated. The results of thread properties and seam pucker were compared.

In respect of seam pucker the best results were established sewing with polyester threads, the reversible strain of which were the least. After washing and drying, the highest pucker was typical of the specimens sewn with cotton sewing threads. It was noticed that increasing the amount of layers in sewing the influence of threads on seam pucker decreases. Washing and drying made considerably greater influence on the occurrence of pucker then time.

This study has practical implications in the clothing and other nearly related industries. In the paper recommendations involved with application of sewing thread and evaluation of seam pucker are presented.

In most cases the changes of sewn thread mechanical properties after sewing is analysed. This study is aimed to determine the influence of thread properties on seam pucker. Recommendations in the area of sewing thread and garment quality are based on the research.

The continuing development of the textile and clothing manufacturing industries depends in no small measure on the successful implementation of reliable objective methods for the specification, prediction and control of fabric quality and performance attributes. In the last decade, we have seen several notable examples of fabric design and development, and production and quality control in textile processing and clothing manufacture in terms of fabric objective measurement technology. The quality and performance characteristics of fabrics are related to their low stress mechanical, surface and dimensional properties. The experimental errors involved in the measurement of these properties are known to be much smaller than the errors involved in subjective assessment of fabric quality attributes, especially those made by individual judges. We may define the concept of fabric objective measurement as a necessary and sufficient set of instrumentally measurable parameters which are required to specify the fabric quality, tailorability and clothing performance. In this way, fabric objective measurement technology provides a “fingerprint” of the fabric quality, tailorability and performance implying that any two fabrics will generally differ at least to some extent in their objectively measurable characteristics. Fabric objective measurement technology therefore provides the key for scientific and engineering principles to be used for fabric specification and design as well as process control. The most important consequence of the introduction of fabric objective measurement technology will be the promotion of technological communication between various sectors of the textile and clothing industry, research and development workers and all other sectors of industry (e.g. fibre producers, retailing, merchandising, machinery manufacturers) concerned with fibres, textiles and clothing.

The mechanism of strength reduction of sewing threads has been discussed in Part I of this paper. The effect of fabric tightness and certain thread properties like its size, coefficient of yarn‐metal friction, twist direction, number of piles, type of fibre and fibre denier on strength reduction has been studied and found to influence the severity of strength reduction of the thread.