减少纱线纱疵的方法探讨

介绍了纱线纱疵产生的原因、检测方法以及在纱线中的表现形式,分析了原料性能、加工工艺条件以及设备条件对纱线纱疵的影响,提出了减少纱线纱疵的方法并介绍了控制纱疵的方法.     

减少纱线纱疵的方法探讨

介绍了纱线纱疵产生的原因、检测方法以及在纱线中的表现形式,分析了原料性能、加工工艺条件以及设备条件对纱线纱疵的影响,提出了减少纱线纱疵的方法并介绍了控制纱疵的方法.     

减少纱线纱疵的方法探讨

介绍了纱线纱疵产生的原因、检测方法以及在纱线中的表现形式,分析了原料性能、加工工艺条件以及设备条件对纱线纱疵的影响,提出了减少纱线纱疵的方法并介绍了控制纱疵的方法。     

气流纱的弱点分析

当纺织工业中的产量增加时 ,生产过程中施加在纤维及纱线上的应力及应变也提高了。结果产生了高的断头率 ,这将导致机械及生产效率降低。然而 ,这个负面的效应可以通过对纱上的弱点进行特殊的分析而得到抑制。只知道纱有弱点不够 ,知道它们存在的原因更加重要 ,以便于在将来的生产中避免它。这篇文章阐述了 Uster Tenso-jet上的一个特殊的附加组件 ,它用来对气流纱的弱点进行分析。在与瑞士的 Zellweger Uster公司联合执行的一个发展项目中 ,在科学学习的范围内 ,为Uster Tensojet设计了一个特殊的组件。这个组件能在为弱点位置规定的极…     

利用先进的纱疵分级系统分析纱线

当今因为经济原因,为相应的织物选择正确的纱至关重要,连续的进料检验才能保证产品达到稳定满意的质量,清纱和纱疵分级系统在这方面扮演着重要的角色.清纱曲线的设置在电清刚开始问世时是很困难的,需要专家来解决.     

利用计算机进行纱条疵病诊断的体会

1　前言纺织厂是多工序、多工种、多品种的连续性生产,由于质量特性值多,影响产品质量的因素不仅范围广,而且错综复杂,加之频繁的品种、规格变动,设备的不断调整等原因,使得质量分析和经验的积累都比较困难,所以利用计算机,并配以适当的专用软件,组成纺织质量管理分析系统,已成为现代化生产及管理的技术特征。在公司领导的大力支持下,我们于1996年6月装配了由西北纺织工学院研制的“纱条条干专家诊断分析系统”软件(以下简称“专家系统”)。通过一年的使用,我们认为该软件快捷方便、诊断的疵病产生范围准确恰当,是一个很好的判疵工具。2　专…     

乌斯特纱疵分级仪应用的探讨

本文结合生产实践,探讨了乌斯特纱疵分级仪在纺纱生产质量控制中的应用。     

Evaluation of the dual-feed rotor spinning unit based on airflow dynamics and blended yarn properties

In fiber processing on a rotor spinning machine, the fiber orientation gained in pre-processing stages like carding and drawing is mainly lost as the fibers enter the rotor interior for further processing. To improve fiber orientation and facilitate fiber blending, a new dual-feed rotor spinning unit is proposed. We present a comprehensive numerical evaluation of the airflow dynamics in the original and the proposed rotor spinning unit based on finite volume methods. The velocity profiles, pressure distribution, vortices, streamlines, and drag force in the two prototypes are evaluated. Results reveal that the velocity magnitude and pressure in the dual-feed unit adopt an even pattern and the total drag force reduction of up to 60–80% is achieved. Comparison of the yarn quality properties of the two systems showed that the dual-feed spun yarns possess superior quality compared to the conventional yarns.     

拉瓦尔管结构对涤纶全拉伸丝吸丝枪流场的影响

为给提高吸丝枪性能提供技术支持,使用CFX 12.1软件对具有不同拉瓦尔管结构的吸丝枪内部流场进行模拟,分析了流场分布与吸丝性能之间的关系,阐明了拉瓦尔管结构对吸丝枪性能的影响机制。模拟结果和实验结果相吻合,合理的拉瓦尔参数为收缩角α= 90° 和扩大角β= 6°。合理的收缩角有利于气流在拉瓦尔管中平稳加速,减少返流与乱流,并避免产生强烈的正激波,减少动能损失,从而提高吸丝效率;合理的扩大角能使吸丝枪内气流速度周向分量和高速高密气流区域长度适中,增加空气对纱线的拖曳力,减小管壁对纱线的摩擦力,降低正激波产生的动能损失,提高吸丝效率。     

喷孔结构对FDY型吸丝枪流场影响的数值模拟分析

使用软件CFX 12.1对具有不同喷孔结构的吸丝枪内部流场进行模拟,分析了流场分布与吸丝性能之间的关系,阐明喷孔结构对吸丝枪性能的影响机制,得到合理的结构参数:喷孔数N为3,孔径d为2.0 mm,喷孔角度为75°。结果表明:增加喷孔数减少了喷出气流的自由扩散,增强其方向性,提高枪内管壁附近空气密度和空气周向速度分量,从而提高吸丝力;过大的喷孔数增加了喷出气流间的冲突,减小了吸丝力;合理的孔径有利于强烈涡流的形成,并避免正激波的产生,提高了吸丝力;喷孔角度主要控制空气周向速度分量的大小,引起涡流强度变化,从而改变吸丝力;吸丝效率和气流分布密切相关,尤其是空气周向速度分量影响最大;正激波的产生不利于吸丝力的提高,应尽量避免。     

An investigation of yarn snarling and balloon flutter instabilities in ring spinning

Abstract

This article reports theoretical and experimental investigation on yarn snarling and balloon fluttering in ring spinning. Yarn snarling and balloon fluttering affect yarn breakage in ring spinning. The theoretical model has incorporated the tangential component of air drag on a ballooning yarn, which was ignored in previous models. The results show that yarn snarling happens in the balloon when the ratio of yarn length in the balloon to balloon height is greater than a specific value that depends on the yarn type and count. Yarn tension experiences an obvious change before and after yarn snarling. The balloon flutter appears between normal balloons while the balloon loops are changing. Fluttering balloon shapes that oscillate periodically between two and three loop configurations as yarn tension varies periodically have also been observed experimentally.     

喷气纺纱线结构特性的算法研究

喷气纺纱线的结构特性是AiF 14513 N喷气纺纱质量研究项目的一部分。介绍了一些研究喷气纺纱线结构特性的基本概念,有助于分析喷气纺纱线与标准纱线在结构、毛羽和直径等性能方面的差异。     

突发性纱疵产生原因的快速诊断

介绍了突发性纱疵的快速诊断方法。通过对工厂生产的常规品种的分析,提出优化牵伸比,使不同品种的生产工艺保持基本一致,这样在波谱图上出现的异常峰值的位置只与设备的状态相关,为快速诊断带来了便利。根据工厂生产的实际经验,总结出异常峰值的位置与其对应的设备机构缺陷的位置关系,查找出突发性纱疵产生的原因及排除设备缺陷的措施,快速诊断,及时调整设备与工艺,把纱疵消灭在萌芽之中,提高了纱条的质量。     

包芯花式线性能的研究

研究包芯纱的性能对结子花式线拉伸性能的影响得出以下结论：不同线密度纱线对断裂伸长影响很大,而对强度影响不大;就原材料的影响来看,发现在研究的纱线中,对聚酯纱线断裂强度的影响最大,对棉纱的断裂伸长影响最大。试验结果表明：一种组分性质的微小变化都有可能对最终的花式线性能产生很大的影响。     

Research on Sirospun yarn torque using airflow false twisting device

Yarn torque is one of the most important indexes of yarn quality, which is determined on the mechanical state of the constituent fibers and their configuration in the yarn. The fiber tension within a yarn was proposed to be the most influential factor governing the magnitude of yarn torque by Bennett and Postle. Therefore, the research on Sirospun yarn torque is investigated by analyzing the fiber tension at spinning triangle in this paper. Firstly, theoretical models of the fiber tension distributions at primary and final spinning triangles are presented, and corresponding residual torque within a yarn due to the fiber tension is given. The relationships between the yarn torque and the spinning triangle parameters are analyzed theoretically. Secondly, as an application of the proposed method, a modified Sirospun spinning system with an airflow false twisting device which can change spinning triangle parameters are investigated, and the properties of spun yarns produced by the modified system are evaluated and analyzed. It is shown that with the increasing airflow pressures, the Sirospun yarn shows a more and more uniform distribution of tensile and compressive stress within a yarn, and thus the yarn torque decreases correspondingly.     

Influence of fibre strength and yarn structural characteristics on tensile failure of blended spun yarns: a prediction model

The study reports on the static failure behaviour of P/V blended ring, rotor and air-jet spun yarns explained on the basis of fibre failure coefficient. Fibre failure coefficient is an index introduced to represent fibre break and slip in combination occurring during tensile failure. Fibre break/slip during tensile failure is found dependent on fibre strength, fibre cohesiveness and internal structural developments in yarns. Tensile failure behaviour of ring, rotor and air-jet yarns found to be different owing to their difference in fibre consolidation mechanism. The contribution of individual components towards fibre failure coefficient varies with the spinning technology. An attempt has been made to develop mathematical models to explain the spun yarn failure behaviour under static condition. The developed mathematical models have incorporated the fibre property (fibre strength) and few structural characteristics of yarns which are strategically selected to justify the essence of models to enhance the prediction capability. Individual models are developed for ring, rotor and air-jet yarns owing to their structural changes caused by their inherent fibre consolidation mechanism. The developed mathematical models are free from assumptions and based on pure applied mathematics and have very high potential for prediction of spun yarn failure behaviour.     

数码转杯纺成纱原理及其纱线特点

为开发新颖的纱线品种,提高纱线生产效率,提出数码转杯纺成纱方法并介绍其原理,对成纱色彩特点进行研究。数码转杯纺采用３ 组分异步喂入的方式,纤维通过分梳辊的梳理和混合,在转杯内离心力作用下再次混合并凝聚成须条,经加捻后成纱,再由引纱罗拉导出形成特种纱线。该工艺过程可随机调控转杯纺成纱的线密度及混纺比,生产多种混合均匀的混色纱和混纺纱品种。分别纺制了混色纱、变色纱、段彩纱、竹节纱、彩节纱和双变纱等典型数码纱,并对其色彩特点进行分析,总体来说数码转杯纱不同颜色的单纤维混合均匀,纱线颜色柔和。