Effect of Static False Twist on Rotor Spinning

Many practices of the rotor spinning show that the false twist effect of the navel is much more complicated than that of the one point based friction model. Both ends of the yarn＇s twist and torque changes were analyzed under the static effect of the navel, and then established yarn twist ratio on both ends. It verified its correctness through simulation experiment by designing the experimental device, and analyzed the effect of navers radius on twist ratio.

CALCULATIONS AND ANALYSIS OF THE SPINNING ROTOR BEARING SYSTEM BY USING FEM

In this paper the formulation of finite element analysis for frame casing problems of theharmonic type is described. Attention is paid to the OE spinning rotor bearing assembly (RBA)’ sdynamic model, whose harmonic parameters, such as natural frequencies and modal shapes, aresolved by means of structural analysis program using personal computer, i.e. SAP84 software. Ac-cording to orthogonal factorial design table (OFDT), the predominant sensitive influential factors(PSIF) of RBA are determined.

THE PRACTICE OF ROTOR SPINNING IN PRODUCING SILK NOIL YARN AND THE DEVELOPMENT IN WOVEN FABRICS AND KNITTED GOODS

At present, we have succeeded in producing silk noil yarn by rotor spinning, and obtained good economic benefits. In this paper, through combining with the recent producing practice, systematically discussing and analysing the technology in the process of producing silk noil yarn by rotor spinning, we develop the new technology which is suited to produce silk noil yarn by rotor spinning, and address several noticable problems. The conclusions have been put into practice and proved to be effective and reliable. It can be consulted by the textile mills.

THE INFLUENCE OF COMBING ROLLER SPEED ON PURE RAMIE NOIL ROTOR YARN QUALITY AND SPINNING PERFORMANCE

This paper reports the optimum design of combing roller speed with reference to yielding 6-13 Ne(98.4—45.4 tex) pure ramie noil rotor-spun yarns. The universal rotatable composite design is adopted to get the highly precise regression equations, in which the variables are combing roller speed and yarn linear density considered to be the main technological parameters of combing roller and, the responses are the evaluation indexes concerning spinning stability, fiber length distribution of fibre ring from rotor groove and yarn properties. Based on these regression equations, the contours are plotted to analyse the influences of the parameters on the evaluation indexes; the optimization multicriteria mathematical model is simultaneously established to obtain the optimum parameters with the aid of Object Programming Approach along with Constrained Random Ray Method. Finally, an experiment is carried out to further test the acceptance of the calculated optimum values. It is shown that, for any yarn linear density within 6—13 Ne (98.4—45.4 tex), combing roller speed varying from 5000 to 9150 r/min affects content of extra-long fibre in fibre ring from rotor groove and yarn properties but does not significantly influence spinning stability; 7075 r/min, at which the SAQ-12 type of saw-toothed combing roller runs, is recommended to be the optimum combing roller speed for producing 6—13 Ne (98.4—45.4 tex) pure ramie noil yarns, where a compromise is achieved among the lowest content of extra-long fibre in fibre ring, the best spinning stability and the best yarn properties.

FUZZY DECISION-MAKING OF COMBING ROLLER COVERING FOR SPINNING PURE RAMIE NOIL ROTOR-SPUN YARNS

This paper deals with the types and specifications of combing roller covering for spinning pureramie noil rotor-spun yarns.A handling mode combining Fuzzy Decision-making and FuzzyCluster Analysis has been used for analyzing the experimental results.It is shown that,with regard to the specifications of the sawtooth clothing of the combing rol-ler,large working angle,large tooth pitch,fine tooth shape,short tooth height,smooth finish andgood wearability are of benefit to improving the spinning stability and the spun yarn properties.The pinned combing roller,however,regardless of its complicated process of production,is sug-gested to be preferred for spinning the pure ramie noil rotor-spun yarns.The handling mode used in this work is efficient in improving the reliability and objectivity ofthe conclusions and can be used for solving the similar problems.

Theoretical Study of the Peripheral Twist Extent Length in Rotor Spinning

The mathematical model of peripheral twist extent(PTE) length was set up by studying the kinematics anddynamics of the yarn in rotor groove. The value of PTElength was calculated by using numerical method, andthe factors affecting the PTE length were also discussed.The results show that the theoretical predicted value ofPTE length seems to be consistent with the measured val-ue. The yarn linear density and rotor speed have re-markable effects on PTE length. The parameters includ-

Yarn Tension at Peeling Point in Rotor Spinning

Based on the work and energy principle as explained inprevious literatures,the yarn tension at peeling point inrotor spinning was analyzed and calculated numericallyin this paper.The results show how raw materials,rotorspeed,rotor diameter,yarn linear density and navel de-sign can have certain definite effects on the tension valueat the peeling point.

Promotion of Semiautomatic Piecing Quality in Rotor Spinning

Discussed in the article are the factors for the imperfect quality of piecing based on the principles and the key technologies of semiautomatic piecing. Furthermore, three measures including changing the shape of seed yarn tail, changing the feed speed and removing the damaged fibers are put forward. Experimental results prove that the former two, especial the second one, offers better piecing quality.

Effect of Spinning Parameters on Thick, Thin Places and Neps of Rotor Spun Yarn

Defect free yarn is a great demand for spinner, knitter, and weaver and also other textile personnel because numerous end products from knit apparels to woven fabrics, from towels to sheets and from carpets to industrial fabrics characteristics significantly depend on the physical properties of yarn. The qualities of rotor yarn are really directed by spinning parameters. The aim of this study is to observe the effect of spinning parameters such as rotor diameter and speed on thick, thin places and neps of yarn in rotor spinning process. 0.11 sliver hank of 100% cotton was used to produce 12 Ne yarn. 65% virgin cotton and 35% wastage cotton were mixed together. The positive impact of spinning parameters on yarn properties were accessed by thick places, thin places and neps. Results indicate that the yarn qualities were improved with increasing of rotor speed and rotor diameter. The rotor diameter was settled to 43 mm while rotor speed fluctuated from 35,000 to 45,000 rpm and rotor speed was fixed to 35,000 rpm while rotor diameter across contrasts from 43 mm to 66 mm.

MODEL MEASUREMENT AND ANALYSIS OF ROTOR BEARING SYSTEM OF OE-SPINNING

This paper describes a CAD compatible software which can conduct model measurementand analysis on a dedicated computer system.This system which can provide modal testing andanalysis capability is also demonstrated briefly.It addresses four main tasks:(1)modal testingand data acquisition,(2)data analysis and correlation,(3)output of modal analysis results,(4)predictions of modal parameters using Structural Dynamic Modification (SDM)software.

The Yarn Curve and Tension in Rotor Spinning

The effective way of finding the yarn curve shape and tension of OE(open end) yarn inside the rotor is carried out and treated by dividing the yarn curve into two parts, from which the trajectory of the yarn sliding on the navel surface is also obtained. It is pointed out that the yarn curve shape and tension will both fluctuate with the trajectory's revolving cycle inside the rotor. However, the fluctuation is not too great, so the motion can still be regarded as approximately steady for dynamic analysis.

Study on the Rotor Spinning Processing of Spun Silk/Cashmere Blended Yarn

This paper studies rotor spinning blended yarn produced of spun silk and cashmere.Nine samples were spun,from three different opening rollers and different navels.According to the Uster test results of yarn quality properties,optimum selection is done by using analysis method of combining fuzzy decision-making and fuzzy pattern classification.Experimental plan is designed based on universal rotated experimental design,and the method of confined optimization is used to optimize the speed of opening roller,the speed of rotor and twist factor,according to the results of yarn quality test by Uster.

Study of Rotor Spun Basofil/Cotton Blended Yarn Quality Characteristics during Optimisation of Processing Parameters

Yarn quality characteristics are affected by processing parameters. A 36 tex rotor spun yarn of 50/50 Basofil/cotton (B/C) blended yarn was spun, and the spinning process optimised for rotor speed, opening roller speed and twist factor. Selected yarn characteristics were studied during the optimization process. During the optimizations process yarn elongation and hairiness reduced with increase in rotor speed. Tenacity increased with increase of rotor speed. The increase in TF caused tenacity and CV of count to increase up to a peak and then started to decrease with further increase of TF. While TF caused an increase in yarn hairiness, elongation decreased to a minimum level and then started to increase with further increase of TF. CV of count and hairiness increased with increase in opening roller speed, but tenacity and elongation decreased with increase in opening roller speed. The optimization process yielded the optimum levels for rotor speed, opening roller speed and twist factor (TF) as 45,000 rpm, 6,500 rpm and 450 respectively. As per uster Standards the optimum yarn showed good results for CV of count, CV of tenacity and thin places/km.

TENSILE BEHAVIOUR OF ROTOR SPUN YARNS

This paper deals with the tensile behaviour of rotor spun yarns. Having regard to the spe-cial construction of rotor spun yarn, some modifications for Hearle’s theory have been made inorder to apply Hearle’ s theory to rotor spun yarn. The paper then goes into calculating thetensile curve and investigating the effect of main parameters and spinning conditions on thetensile behaviour of rotor spun yarn. It was found that the following facts are noteworthy forimproving the mechanical properties of rotor spun yarn: (1) Selecting suitable navel so as tocontrol the P. T. E. length within a reasonable range. (2) Improving the design of single fibresupply device to decrease the amount of spoiled fibre and hence increase the effective fibrelength. (3) Increasing spinning yarn tension without yarn break to enhance the fibre migrationratio. (4) For the rotor spun yarn of industrial use, it is the way to increase the yarn strengththat the rotor groove should be designed with the groove angle beneficial to decrease the yarnspecific volume.

BALANCING TORQUE OF SINGLES COTTON ROTOR YARNS

This paper reports a recent development of a yarn modification process to produce torque balanced singles spun yarns. Taking advantages of the core-sheath structure of unconventional spun yarns, we have developed a yarn modification process and applied it to singles yarns spun by rotor spinning. Torque free singles yarns have been produced from 100% cotton fibers. The spirality of resultant single jersey knit fabrics has been greatly reduced or, in some cases, completely eliminated. Properties and performance characteristics of both parent and modified yarns as well as their resultant fabrics have been evaluated including the yarn tensile properties, surface properties, handle, air permeability, burst strength, and pilling resistance of the fabrics.

Study of the Twist Distribution inside Rotor

In this paper, the kinematics and dynamics of the yarn on the navel were studied. A series of twist distribution curves were obtained by numerical calculation. The results show that the navel is essential to the false twist development on the yarn arm. The fiber surface properties, yarn linear density, rotor speed and diameter, navel design are all the parameters having remarkable effects on the false twist level inside rotor.

Experimental Investigations on Fiber Motion within Rotor Spinning Unit

An experimental platform is constructed to photograph fibers' motion within rotor spinning unit, which is mainly composed of a transparent rotor and a transport channel based on the similarity theory. The fibers will stretch and gather into a fiber bundle in the transport channel. The velocity of fibers is increasing along the inlet to the outlet of the transport channel, and the fibers' maximum velocity appears at the outlet of transport channel. The straightness of the fiber bundle is related to the convergence degree of the transport channel, and the greater the convergence degree is, the straighter the fiber bundle stretches. The results will provide a useful insight to the yarn-forming mechanism of rotor spinning.

转杯纺纱机的发展现状及趋势

转杯纺属于自由端纺纱,具有纺纱速度高、工艺流程短、原料适用性能广等优点,是较为成熟的新型纺纱技术代表之一。文章分析了转杯纺纱机的市场情况及发展现状,阐述了转杯纺纱技术的创新应用,并提出了转杯纺纱机发展需求及思路。具体体现为:我国转杯纺装机量具有全球优势地位,国产半自动转杯纺纱机进步明显,具有国际竞争力,但全自动转杯纺纱机与国外相比差距明显,未来随着转杯纺纱机在差异化结构、差别化原料、高支数转杯纱开发方面优势的凸显,以及用户友好智能化转杯纺纱机的成功研发,转杯纺纱技术的优势将不断凸显,推动棉纺行业高质量发展。

基于Ω漩涡识别方法探究转杯凝聚槽漩涡对纺纱质量的影响

为了更为准确地识别与分析转杯纺转杯内复杂多变流场中的涡流情况,提出了一种结合Ω漩涡识别方法和图像处理的漩涡识别技术。文章对Fluent仿真得到的转杯流场进行了分析,得到了凝聚槽平面的漩涡数量与面积,并进一步探究了凝聚槽内漩涡分布对纱线质量的影响。结果表明:Ω漩涡识别方法对凝聚槽漩涡有较好的捕捉效果,经过图像处理后可以定量化分析转杯内部气流流场的涡流情况;凝聚槽内漩涡主要分布在输纤通道出口处以及背后气流交汇处;随着转速的提升,转杯凝聚槽内细小漩涡面积增加,不利于纱线聚合;较大直径转杯凝聚槽部位漩涡面积更小,有利于纤维聚合。文章通过图像识别的方式探究转杯内流场的漩涡分布特征,为优化转杯纺结构提供了一定理论支持。

双分梳转杯纺花色牛仔纱设计及产品开发

为了解决传统牛仔纱颜色单调、织物风格单一,且存在染色污染的问题,从牛仔纱线花色设计出发,详述选用黑白粘胶纤维、通过改变不同颜色纤维组分比例,在双分梳转杯纺单头试验机上纺制5种双节花色变化牛仔纱的方案设计;选取颜色风格为灰黑的牛仔纱,以分梳辊转速、转杯转速及成纱捻度3因素设计正交试验,对比不同试验水平所纺的纱线性能,优选出最佳纺纱工艺组合及其织物织造工艺。指出:在分梳辊转速为7.5 kr/min、转杯转速为50 kr/min、纱线捻度为65捻/(10 cm)的条件下,纺制的牛仔纱质量较好,织物具有明显的灰黑牛仔风格;采用双分梳转杯纺技术、改变原料组分及交替比例的纺纱模式,能直接进行牛仔纱色彩设计,生产方便高效且过程环保;增加有色原料组分变化比例及变化次数,可纺制出多节渐变的花色牛仔纱。