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In general, if a yarn is spun or twisted to a range of twist factors, it is found that the yarn strength increases with the twist factor up to a certain value of it, beyond which the strength begins to decrease, slowly at first, then more rapidly. The general shape of the twist-strength curve for continuous filament and spun yarns is shown in figure 2 below: The strength of continuousfilament yarns tends to increase slightly as the twist is increased from zero. The binding effect of twist enables the stronger filaments to support the weaker. This effect is small because there is normally little difference in tensile properties between filaments. The filaments in a continuous filament yarn make their maximum contribution to yarn strength when they are parallel to the axis of the yarns, that is when the twist is zero. Any finite twist, only part of the tension along the fiber axis contributes to the strength of the yarn, and so, as the angle of twist increases, the yarn streng...

computerized marker”. The objective of this research is to conduct a comparison in pattern and marker making between the CAD and manual methods as regards individual course steps and total time values, and to determine the effective of model complexity on these times. For this purpose, four models starting from the simplest to the most complex were designed, and the course steps of the traditional manual method and CAD were first established. Each course step was carried out repeatedly by an expert according to statistical norms. In order to determine in which steps and for which model CAD can be more productive, the data obtained for both methods was compared with respect to the individual time value of each course step and the total time values. Furthermore, the possible causes of the results obtained were discussed and suggestions were put forward. Introduction •        Devices performing high-tech services in the apparel industry are commonly ...

Present view of static charges in textiles textiles static charges is a variety of mechanisms may cause charge transfer to occur at surfaces in contact. Consequently, large charges will form on the surfaces, but these will leak away through the air, the material, or surface-dressings, and observed charges are much smaller. Leakage through the air occurs until the field near the charged surface is reduced to a value which the air can support. If the ratio of the conductance of the material to the speed of separation is high enough, current will flow the material and further reduce the charge.The leakage will take place from the material just beyond the point of separation, either across the gap to the other surface or to points on the material behind the point of separation. If other conductors are present in the neighbourhood, some current may flow to them. The limiting condition for high static charges, and hence the susceptibility to troubles in use, has been shown to depend o...

Types of Yarn twist different types of yarn twist S twist Z twist“S” TWIST: A single yarn has “S” twist if when it is held in the vertical direction , the fibers inclined to the conform in direction of slope of the contact portion of the letter “S”. axis of the yarn “Z” TWIST. A single has “Z” twist if when it is held in the vertical direction, the fibers inclined to the yarn axis conform in the direction of the slope to the central portion of the letter “Z”. DIRECTION OF TWIST: In the designation of yarns, it is essential to specify the direction of twist. Besides its importance in simplifying the trade, it is of great technical importance in designing fabrics. For example, in a twill fabric, the direction of twist in the yarn is of particular importance in determining the predominance of twill effect. For a   right-handed twill, the best contrasting effect will be obtained when a yarn with Z twist is used; on the other-hand a left-handed twist will produce a fabric ha...

Twist plays an important role in affecting the arrangement of fibers or filaments in the cross-section. In staple yarns , twist is essential to hold the fibers together and to impart some degree of cohesiveness to the structure. On the other hand, the filaments in a multifilament yarn would fray away if there were no cohesive forces holding them together. Furthermore, the formation of plied yarn or cabled yarns is also achieved by twisting single or plied yarns together to produce a coherent linear structure. In other words, twist is a means by which a bundle of fibers, filaments, or yarns in a plied yarn is held together so that the ultimate structure is made capable of withstanding the stresses and strains and the chafing action of many processes involved in the manufacture and use of textile fabrics. The role of twist is very profound in determining the properties of finished yarns, vis-à-vis fabrics. When a number of components ( fibers or filaments) in a continuous strand a...