A New Method for the Determination of Yarn Hairiness by Digital Fibrograph

Compact spinning, as a new kind of spinning technology, has gained wide attention because of its great reduction in spinning triangle and yarn hairiness. In order to meet the demand of high-grade clothing, research on further improving the performance of compact spun yarn is the emphasis. Of all the existing compact spinning systems, the four-roller compact spinning with lattice apron is most widely used at present because of its low cost. Therefore, this paper aims to put forward a new kind of device to improve yarn performance for four-roller compact spinning systems. Related experiments have been done to verify the efficiency of the device, and the mechanism is analyzed by computational fluid dynamics. The numerical simulation shows that the device can change the direction of airflow and increase the velocity in the directions of transverse condensing and thickness. It is shown that the air damper is convenient to use and has potential applications in spinning compact yarns with better performance.

mentioning

confidence: 99%

Investigation into four-roller compact spinning with air damper for improving yarn performance

Yang

Sun

et al. 2021

“…This is because the actual amount of hairiness as well as hair length can be digitally detected by the photoelectric method at any desired level away from the yarn axis or yarn surface. 11 In this situation, many hairiness measurement instruments have been developed using the photoelectric principle, such as Zweigle G565 meter, Uster hairiness detectors, Shirley SDL098/98 yarn hairiness meter and Changling YG172A hairiness meter. More attempts have also been tried to improve the accuracy of the yarn hairiness measurement.…”

mentioning

confidence: 99%

A novel analysis of spun yarn hairiness inside limited two-dimensional space

Xia

Liu

Wang³

et al. 2019

Surface hairiness of spun yarns is critical to the yarn post-processing deficiency and resultant fabric quality. Several test methods are available for measuring yarn hairiness but they cannot detect the accurate hair amount and precise hair length. This paper provides a novel method to perform accurate hairiness tests on the spun yarn. A new test apparatus was devised by installing a blowing pipe outside of the hairiness testing area comprising a projection receiver and a corresponding laser. The rectangle end plane of the blowing pipe air inlet is vertical to the laser plane and tangent to the edge line of the projection receiver surface. Pressure generated through this inlet stretches yarn wild hairiness straightly in one direction, and fully maps accurate hairiness amount and length configuration on the projection receiver surface. The subsequent measurement showed that this novel test apparatus detected more hairiness with improved accuracy in both number and length of hairiness. Approximately real gravimetric hairiness weight can be obtained by this method which is impracticable for other conventional photoelectric apparatus.

“…1,2 Since the yarn hairiness has a great impact on end-use products, methods for measuring yarn hairiness have been widely studied and developed. [3][4][5][6] Of these methods, optical measurements are the most common for evaluation of yarn hairiness, which can be grouped into two categories: number-based and length-based statistics. For number-based statistics, the numbers of hair fibers in lengths of 1-9 mm, that is, the distribution of hairiness lengths, are used to measure yarn hairiness; the length-based statistics counts the total length of protruding fibers over 10 mm, that is, the H index of hairiness.…”

mentioning

confidence: 99%

Analysis of detectable angles of yarn hairiness in optical measurements

Sun

Pan

Zhou

et al. 2016

Obstructed by the yarn core, the detectable length and the detection rate of a hairy fiber are mainly determined by the geometry of the yarn and the location of the fiber in an optical system. This paper presents a new theoretical method of analyzing detectable angles of yarn hairiness in optical measurements. Firstly, a cylindrical model of the yarn core is constructed by using the yarn diameter, and spiral lines on the cylinder are drawn using the twist angle of the yarn. Secondly, hairy fibers are simulated by short-line segments passing a spiral line and the Z-axis of the model. The yarn model is projected onto a plane under the assumption of a collimated light source, which is the condition similar to that of optical measurements. The yarn model is cut by a plane parallel to the axes of the Cartesian coordinate system ( XOY) at the emergence points of hairy fibers. Finally, the relationship between the hairiness length and other factors, such as the test length, yarn diameter and detectable angle (i.e. the angle at which hairy fiber can be detected) is established. It has been demonstrated that the detection angle dictates not only the length of each hairiness but also the rate of detectable hairiness in the scene. Given a detectable angle, the upper and lower limits of detectable hairiness lengths can be predicted. The verification results of the detection rate by three measurement methods indicate that the detection rates of optical measurements have a certain guidance function for correcting the hairiness results of optical measurements.