Dynamic analysis of spinning triangle geometry part 1: validation of methodology

The physical shape or geometry of the spinning triangle directly affects the quality of ring spun yarns. This study developed a technique to measure the geometrical parameters of the spinning triangle during ring spinning using a combination of a clear rubber roller and digital image processing. The clear roller exposed the spinning triangle zone during the yarn spinning process in a non-invasive manner, and yarn properties were not affected. A digital camera recorded images of the spinning triangle. An image processing algorithm was then developed to process the images to measure the dynamic geometry of the spinning triangle. The method was able to effectively measure the width, height and skew of the spinning triangle along with changes in these parameters over time. This technique will be applied in a follow-up study to investigate the effects of the shape of the spinning triangle on yarn quality.     

基于ANSYS的加捻三角区内纤维变形数值模拟

根据纤维力学性质建立加捻三角区有限元模型,利用ANSYS13.0软件对加捻三角区纤维变形进行模拟,结合纺纱实验分析了纤维变形对纱线性能的影响。以JC14.6tex环锭纱和赛络纱为例,得到了相同条件下,环锭纱和赛络纱纺制过程中加捻三角区内纤维的变形规律和实际纺制的两种纱线的性能指标,结果表明：加捻三角区内纤维变形沿着三角区中心线呈对称分布;纤维变形与加捻三角区的形状有密切关系;与环锭纺相比,赛络纺加捻三角区内纤维变形明显较小且变形一致性好;纤维变形对纱线的毛羽和强力有着重要影响。     

Research on flow field in a modified ring spinning system with the air nozzle

Twisting is one of the most important steps in the yarn spinning, which influences the geometry of spinning triangle and determines the properties of spun yarns. Airflow is one of the most important measures on improving yarn spinning. In this paper, a kind of air nozzle with vortex guiding channel was designed and used on the modification of ring spinning system, and the spun yarn qualities was studied by analyzing the airflow field in the nozzle. Firstly, the three-dimensional physical model of nozzle was given using CAD software according to the geometrical size of the practical nozzle model. Then, the numerical simulations of the three-dimensional flow field in the nozzle were given using Fluent software. Finally, two different kinds of yarns 10Ne and 20Ne were spun in the modified ring spinning system with the nozzle installed. The airflow pressure 0.01 Mpa and two different swirling directions, anticlockwise and clockwise, were chosen. The qualities of spun yarns, hairiness, strength, evenness, and number of snarling were measured and analyzed. It is shown that the high vortex airflow can be produced in the nozzle, and then corresponding twist can be produced. For the Z(S) twisting spun yarn, under the effects of the clockwise (anticlockwise) vortex airflow, the pre-twisting would be produced and the yarn twist can be strengthened, while under the effects of the anticlockwise (clockwise) vortex airflow, the untwisting effect would be produced, and the yarn twist can be decreased.     

凹槽形状对气流槽聚纺纱集聚区流场及成纱性能的影响

针对气流槽聚纺纱不同集聚凹槽形状对成纱性能的影响,建立集聚区域三维模型,利用Fluent软件模拟不同凹槽结构的气流槽聚装置集聚区域的流场分布,比较其气流流场的特点。模拟结果表明：在相同负压条件下,非对称凹槽气流槽聚装置的气流利用率高,负压气流方向和集聚方向的速度分别为48.3、24.5 m/s,可有效握持和集聚纤维束,使得输出的须条能够最大程度地集聚,纤维也尽可能多地集中成为主体纤维束,有利于减少毛羽。通过测试所纺27.78 tex苎麻纱的成纱性能,验证非对称凹槽的集聚性能以及集聚气流对成纱性的影响。实验结果表明：采用非对称凹槽集聚装置纺制的纱线毛羽比环锭纺减少了77.58%,成纱强力比环锭纺提高了14.32%,成纱性能显著提高。     

Real-time yarn evenness investigation via evaluating spinning triangle area changes

This paper examines the relationship between changes in the spinning triangle dimensions and evenness of the finally produced yarn. Three kinds of yarn (in different twist levels) were produced and during the spinning process a digital camera was used to record the production process and the triangle behaviour in front of delivery rollers. Using image-processing techniques, three parameters of the triangle (width, length and area) were measured. Then, the correlation between yarn irregularity and changes in the triangle dimensions (with regard to wavelength changes) were evaluated. The acceptable correlation between yarn irregularity and dimension changes indicated that this novel image-processing approach can be implemented in measuring yarn irregularities during the spinning process.     

假捻集聚纺纱方法中基本工艺参数的作用分析

为提高棉纺环锭细纱的成纱质量,提出并介绍了假捻集聚纺纱方法.通过纺纱实验研究采用这种纺纱方法时假捻器转速比、转向以及牵伸形式对纱线条干CV值、毛羽指数、断裂强度和断裂伸长率的影响.结果表明:皮圈牵伸系统所纺纱线质量要好于简单罗拉牵伸系统;假捻器的转向要根据粗纱的捻向而定,如果粗纱为Z捻,则假捻器应为逆时针转动;假捻器转...     

应用给湿装置改善环锭纺成纱毛羽

为减少成纱毛羽,在环锭纺细纱机前钳口与导纱钩之间加装接触式给湿装置,对出三角区后的低捻段纤维须条给湿。借助高速摄影拍摄纱线与导纱轮接触所产生的水雾三角区长度发现,导纱轮直径越大,水雾三角区长度越长。通过测试一落纱平均耗水量,纱线细度相同条件下,随导纱轮直径增大,耗水量增多;同时,纱线细度增大也会增加纺纱耗水量。在上述条件下进行纺纱试验并测试成纱毛羽,14.6 tex 精梳棉管纱3 mm 及以上有害毛羽较普通环锭纺降低了35.9%,19.5 tex精梳棉纱有害毛羽降低了41.1%。14.6 tex 精梳棉管纱络筒后3 mm 及以上有害毛羽较普通环锭纺筒纱降低了41.6%。结果表明,对环锭纺须条给湿可大幅度减少成纱有害毛羽,从而提高纱线品质。     

导纱钩运动引起的纺纱三角区变化对成纱性能的影响

为探索导纱钩运动特征与环锭纺纱品质之间的关系,建立了整管纱线环锭纺制过程中的导纱钩运动模型,基于此运动模型,分析环锭纺纱成纱区内须条与前罗拉包围弧长度变化的特征,探索纺纱三角区几何面积变化规律,推测纺纱三角区变化对成纱性能的影响。理论分析结果表明：导纱钩周期性的升降运动使得纺纱三角区面积产生对应的减增变化,直接影响成纱毛羽。结果显示：同一卷装位置对应的纺纱三角区面积减小时,纤维受到的控制力更大,成纱毛羽相应降低;整管纱线的毛羽性能受三角区面积变化与气圈大小等多种因素共同影响。     

Effects of directed movement of fibres in a twist triangle on yarn quality

This work investigates the effect of directed flow of the fibres in a twist triangle on yarn properties. This is done using different clip‐on attachments positioned on the front rollers of a ring spinning frame. Seven sets of rollers (plain non‐grooved; 75°‐biased left‐to‐right grooved; 75°‐biased right‐to‐left grooved; 15°‐, 45°‐ and 75°‐biased grooved from both sides towards the centre and solo) are made and positioned immediately below and parallel to the top front draft rollers of the laboratory ring spinning frame (tester model 82 KA) so that they can interact with the emerging drafted fibre strand before twist insertion. Afterwards, a 0.495‐ktex (2.02 Nm) finisher worsted roving composed of 55% polyester and 45% wool is fed into each unit of the ring spinning frame to produce a yarn with a yarn count of 30 Nm and a twist factor of 125. The rollers affect the flow of the fibres in the triangle zone and, as a result, the quality of the yarns is affected. A comparison of the yarns produced shows that directing the fibres in the triangle zone could improve the yarn quality. The results indicate that the 75°‐biased grooved (from both sides towards the centre) rollers improve the yarn quality in terms of hairiness, elongation and imperfections.     

优选纺纱器材提高特细纱质量的体会

在细纱工序生产特细纱时,进行了各种纺纱器材的使用试验,其中包括高精度无机械波罗拉、抗绕低硬度铝衬不处理胶辊、新型下销、高耐磨导纱钩、高精密合金钢领等。通过试验表明合理选用纺纱器材可逐步改善成纱的条干值和毛羽值。     

绢丝/锦纶长丝sirofil复合纱成纱性能

 以锦纶低弹丝和绢粗纱为原料,纺制不同捻度、不同喂入间距的绢丝/锦纶长丝sirofil复合纱,测试了复合纱的强伸性能、条干不匀和毛羽。通过对实验结果进行方差分析发现,在实验范围内,复合纱成纱强度和断裂伸长率均随纺纱捻度的增加而增加,但纺纱两组分喂入间距对其影响不大;成纱捻度和两组分喂入间距对成纱的条干不匀CV值影响不显著;复合纱的毛羽指数随成纱捻度及两组分在前罗拉处喂入间距的增加均呈现下降趋势。由此得到实验范围内绢丝/锦纶长丝sirofil复合纱的优化纺纱工艺参数:捻度850捻/m,前罗拉喂入间距18 mm。     

压力棒隔距块在棉纺中的应用

为了探讨在棉纺生产中压力棒隔距块对成纱质量的影响,分析了压力棒隔距块的原理,并在FA506型环锭细纱机上加装不同型号的压力棒隔距块分别纺制出CJ9.7 tex、CJ7.3 tex纱线,测试纱线的毛羽、强力、条干等各项指标并进行对比分析。结果表明,在棉纺中使用压力棒隔距块后,成纱条干有所改善,成纱强力变化不大,成纱毛羽的变化也不明显。     

赛络纺棉/氨纶包芯纱工艺探讨

赛络纺棉/氨纶包芯纱既具有赛络纱条干好、毛羽少的优点,又能发挥氨纶高弹性的特点,是生产各类弹性织物的理想原料。对赛络纺棉/氨纶包芯纱的主要工艺参数(捻系数、须条间距、氨纶丝预牵伸倍数)与纱线质量(毛羽、强度、断裂伸长、条干均匀度)的关系进行了试验和优化分析,为纺制赛络纺棉/氨纶包芯纱提供了参考。     

Analysis of spinning process using the Taguchi method. Part V: Effect of spinning processvariables on physical properties of ring,rotor and air-jet yarns

Abstract

Effect of lap hank and drafts, of various spinning sequence of machines, was studied on physical properties of different yarns using Taguchi method and analysis of variance. The ring yarn is highly even and has the least number of thin places and neps but thick places are the least in rotor yarn. The air-jet yarn is the least even and has the highest number of thin places, thick places and neps. The total hairiness is the least on rotor yarn and number of hairs =3 mm (S3) the least in ring yarn. In air-jet yarn the total hairiness and S3 are the highest. The finer lap hank and higher card draft in preparatory process produces even ring and rotor yarns with lower hairiness. However, the higher speed frame draft improves the evenness of yarn produced from coarser lap hank and lower card draft. Lower ring frame, rotor and high air-jet draft improves the properties of the respective yarns. Increase in ring/air-jet draft increases S3.     

转轮集聚纺纱装置与工艺设计

针对目前负压式集聚纺能耗大的问题,设计了转轮集聚纺纱装置。选用粗纱定量为6.33 g/(10 m)的普梳棉粗纱为原料,采用转轮集聚纺纱装置与传统环锭纺,设计纺纱线密度分别为32.4、24.3、19.4 tex纺制纱线,并对其单纱线密度、断裂强度、毛羽、条干均匀度和捻度进行测试对比,客观评价该转轮集聚纺纱装置的应用效果。结果表明：与环锭纱相比,转轮集聚纱4 mm以上有害毛羽减少量达40%～80%,单纱断裂强度下降1%～3%,断裂强力不匀率下降25%～50%,24.3和19.4 tex的单纱条干均匀度有3%～6%的轻微恶化,捻度基本无影响,说明使用转轮集聚纺纱装置可显著减少纱线的有害毛羽;转轮集聚纺纱装置安装在前罗拉下方,可在环锭细纱机上快速安装与拆卸,实现传统环锭纺与集聚纺的便捷切换,同时该装置具有构造简单、能耗低等优点。     

集聚纺系统在绢纺细纱机中的应用

为进一步提高绢丝的成纱质量,降低生产成本,将集聚纺技术运用在绢纺中,通过分析几种形式集聚纺对绢纺的适应性,将环锭纱和集聚纱的成纱质量进行对比,并对绢丝进行烧毛。结果表明：四罗拉集聚纺应用在绢纺中最具优越性,采用新的四罗拉集聚纺装置能够将须条在集聚区内集束,从而消除加捻三角区;与环锭纺相比,集聚纺纱线的强力、毛羽、条干等指标均较好;集聚纺纱线的损耗率低于环锭纺纱线,并且能够减少工序、节约能源。     

喷气涡流纺工艺对粘胶/涤纶包芯纱性能的影响

为获得更高强力的喷气涡流纺纱线,通过引入涤纶长丝制备喷气涡流纺粘胶/涤纶包芯纱。采用统计分析等方法研究了芯丝线密度、纺纱速度对喷气涡流纺粘胶/涤纶包芯纱强伸性、条干不匀和毛羽的影响规律,同时对比分析了不同纺纱条件下包芯纱的结构外观。研究结果表明：芯丝线密度、纺纱速度对喷气涡流纺粘胶/涤纶包芯纱各性能响应值有不同程度的影响;纺纱速度过高或过低均不利于包芯纱成纱的强伸性提高和条干均匀性改善,纺纱速度的增加会使毛羽H值增大;在一定范围内,增加芯丝线密度有利于包芯纱强伸性的提高,随芯丝线密度的增加,包芯纱毛羽H值减小;此外,选用较大的芯丝线密度和较高的纺纱速度时,纺制的包芯纱芯丝外露现象越明显。     

一种新型窄槽式负压空心罗拉全聚纺系统

本文给出了一种新型窄槽式负压空心罗拉紧密纺系统-全聚纺,并对该系统的结构组成、成纱特性进行了全面分析,最后通过在三家不同纺纱企业进行纺纱实验对全聚纺与网格圈型紧密纺成纱质量进行对比,指出：与网格圈型紧密纺相比,全聚纺成纱条干有所改善,在有害毛羽减少效果基本相同的前提下可保留丰富的短毛羽,成纱强力稍有降低,即成纱综合质量较好。同时,全聚纺系统运行维护成本低、能耗小,具有良好的市场推广应用价值。     

环锭纺纱中加捻三角区内纤维受力分析

加捻三角区是成纱过程中的一个关键区域,其几何形态直接影响到三角区内纤维张力的分布进而决定纱线质量。在三角区的几何参数中,加捻点的水平偏移量越来越受到关注,并被认为是影响成纱质量的重要参数之一。针对此,本文利用纤维在三角区内的运动规律,给出具有任意偏移量的加捻三角区内纤维张力分布的理论模型。指出三角区加捻点处的纤维张力由纤维在前罗拉钳口处的速度、加捻点的输出速度、纤维在前罗拉钳口处的初始张力、纤维弹性模量、纤维横截面积和与中心纤维的夹角决定,为三角区优化设计提供理论参考。     

利用紧密纺技术加工半精纺纱线

根据生产实践经验,分析了半精纺纱线的主要特点,指出传统环锭纺纱过程中因纺纱三角区的存在,使半精纺纱线的毛羽多且长,条干水平不理想,影响织物质量。介绍了紧密纺纱技术以及运用紧密纺技术生产半精纺纱线的优点：强力高、纱疵少、毛羽少,条干均匀等,探讨了紧密纺生产半精纺纱线应注意的事项,及需探讨和摸索的若干问题。