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1.
Structure-properties relations of the drawn poly(ethylene terephthalate) filament sewing thread
Andreja Rudolf, Majda Sfiligoj-Smole, 2008, original scientific article

Abstract: This article presents research into draw ratio influence on the structure-properties relationship of drawn PET filament threads. Structural modification influence due to the drawing conditions, i.e., the birefringence and filament crystallinity, on the mechanical properties was investigated, as well as the shrinkage and dynamic mechanical properties of the drawn threads. Increasing draw ratio causes a linear increase in the birefringence, degree of crystallinity, filament shrinkage, and a decrease in the loss modulus. In addition, loss tangent and glass transition temperature, determined at the loss modulus peak, were increased by drawing. The observed structural changes influence the thread's mechanical properties, i.e., the breaking tenacity, elasticity modulus, and tension at the yield point increase, while breaking extension decreases by a higher draw ratio.
Keywords: PET sewing thread, drawing, birefringence, DSC, DMA, mechanical properties
Published: 31.05.2012; Views: 1258; Downloads: 71
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2.
Thread gauge calibration for industrial applications
Tadeja Primožič Merkač, Bojan Ačko, 2010, original scientific article

Abstract: There are two most commonly used methods for calibration of thread rings, with different measuring uncertainty. The method of mechanical sensing with two balls is mostly used on one-axial measuring machines and on coordinate measuring machines. However, the method of calculating the core diameter of the thread ring combined with the technique of adaptation (in accordance with the method of the smallest squares) is used on the profile scanner. The required tolerances, which are very narrow for adjustable and laboratory thread ring, so the measuring uncertainty may be too high when using the method of mechanical sensing with two balls, and the low quality of some control rings, are the decisive factors for choosing an appropriate method in the industry. This also depends on the laboratoryćs capability of executing a specific method. The measurements of the core diameter of thread rings, which are the main topic of this article, were included into an international inter-comparison in which the main subject was the same thread ring as the one mentioned in this article.
Keywords: thread ring gauge, calibration, pitch diameter, measurement uncertainty, dimensional measurements
Published: 31.05.2012; Views: 1362; Downloads: 23
URL Link to full text

3.
Thread loadings in different measuring positions on the sewing machine
Darja Žunič-Lojen, Jelka Geršak, 2005, original scientific article

Abstract: The knowledge of sewing thread tension determined at different measuring locations on the sewing machine is the basis for the definition of the loading magnitudes acting during the stitch formation process and the locations at which they appear, concerning the stitch cycle or the main shaft turn of the sewing machine. During the stitch formation process the sewing thread is exposed to the highest tension in the region between the tension regulator and the thread take-up lever, following by tension in the region between the take-up lever and the needle and in the region in front of the tension regulator. Dynamic tension and tension force are also dependent on stitch velocity.
Keywords: textile industry, sewing, kinetics of sewing, thread, dynamic thread loadings
Published: 01.06.2012; Views: 1357; Downloads: 67
URL Link to full text

4.
Computer simulation of needle and take-up lever mechanism using the ADAMS software package
Darja Žunič-Lojen, Karl Gotlih, 2003, original scientific article

Abstract: A knowledge of the interactions between a sewing machinećs mechanisms and the sewing thread in the stitch formation process should help us to understand thread loadings in the sewing process. The aim of this work is to analyse the needle bar's kinematics with the thread take-up lever by using computer simulation. A cyclogram was drawn on the basis of modelling and kinematic simulation of a needle bar with a thread take-up lever, and measurements of the thread tension forces in the sewing process. This cyclogram enables analysis of the interactions between the thread and the elements of the sewing machine. The results of these simulations are curves that describe the movements at characteristic points on the mechanism. These give the possibility of pinpointing the exact positions of the mechanism's elements with respect to the main shaft rotation in the sewing machine.
Keywords: textiles, garment manufacturing, sewing, thread, stitch fomation, thread loading, cyclogram, computer simulation
Published: 01.06.2012; Views: 1407; Downloads: 19
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