27—fibre Motion in Roller Drafting

During the spinning process, the drafting process plays an important role because it is closely linked with yarn properties. In this study, two different bottom pins (N–A and N–B) based on a novel drafting device were designed. The simulation results of drafting forces between N–A and N–B demonstrate that N–B shows higher drafting force than N–A at the same draft ratio. Specifically, the drafting forces of both devices show an increasing trend as the front draft ratio increased. In experiments, 14.7 tex and 18.5 tex yarns were spun by N–A and N–B, respectively. The experimental results reveal that N–B produces yarns with better properties, including yarn evenness, imperfections and tenacity, compared to N–A. Notably, the evenness and imperfections of yarns spun by N–B achieve advanced levels and the characteristics of yarn tenacity are close to advanced levels. The experimental results verify that different drafting forces between N–A and N–B devices have an important impact on the yarn evenness, imperfections and tenacity, but not on the hairiness.

“…By replacing the contact area component in equation (2) with the corresponding JKR component, the friction force at the point of contact between with adhesion can be obtained:…”

Section: Design Of Bottom Pinsmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Investigation into novel drafting systems on ring spinning frame for improving yarn properties

Quan

Cheng

et al. 2022

“…The wavelength distributions of these disturbances usually have local maxima, and the local central tendencies are related to the length characteristics of the fiber and the draft involved. Classical theory [ 1,3,4,5] held that the fiber length was one of the most important determinants of the problem, and many writings have assumed that the length distribution of the fiber involved is constant. In fact it is quite variable [8,9] in many respects.…”

Section: Drafting Wavesmentioning

confidence: 99%

Problems and Possibilities in Sliver Monitoring

Lord

1987

Sliver monitoring permits the reporting of errors at the time the material goes out of tolerance during processing. This can greatly reduce the waste of material, time, and money, and it can also improve the quality of the product. Adequate monitoring is only possible if the requisite parameters are measured, but most measuring systems react to changes in several parameters and create ambiguity. Currently, none of the parameters such as fiber length, crimp, and silver bulk are measured continuously, even though better system control would be likely if variations in these data could be incorporated into the control devices. This paper discusses these problems in greater detail and suggests a number of possibilities of extending the range of data available for use in monitoring and control systems.Monitoring equipment draws attention to out-oftolerance material being produced at the time the errors are created by the machine in question. It also provides a managerial tool to keep track of the performance of machines, materials, and operators [2]. The parameters to be monitored depend on the interactions between the various machines in the operational flow line and the textile material flowing through. The question of which parameters need to be monitored is discussed in this paper.

“…For many years, the motion of floating fibers during drafting has been the subject of considerable theoretical work directed toward determining the effect of assumed fiber motions on the drafted sliver with the aim of controlling the floating fibers effectively and to improve the sliver regularity. 4,[7][8][9][10][11][12][13] Foster 14 suggested that a complete theory of fiber motion that would explain the forces acting between the fibers in terms of the arrangement and distribution of the fibers in the drafting zone, and the motion of the fibers in terms of the forces. Yan and coworkers 15 expressed the condition of the fiber acceleration in a probabilistic form regarding the condition in which the drafting forces are greater than the control forces and concluded that the distribution function principle could be used to give the overall variance of the accelerated points.…”

mentioning

confidence: 99%

Fiber motion and the accelerated point distribution in roller drafting

Mupfudze

Cao

Shen

et al. 2018

In this study, the tracer fiber method was used to determine the accelerated point distribution in both the break draft and main drafting zone of the drawing frame with varying different draft parameters. Viscose, cotton, and polyester slivers were used respectively. For the different parameters, the tracer fibers of known length were embedded in the single sliver strand, and measurements of their positions before and after drafting were taken. These measurements of the positions of tracer fibers before and after drafting were then used to deduce the nature of the fiber movement, thus determining the distribution of the accelerated points. The accelerated point distribution under different parameters was obtained. Gauss distribution was found to suitably describe the accelerated point distribution curve under different parameters used in this study. The pressure bar to some degree imparts a significant control of floating fibers within the drafting zone. The relationship between the sliver unevenness and the accelerated point variance (CV) was also discussed.