The relevance of false-twist addition on ring spun yarns by means of rotary threaded surfaces

A novel concept of producing false-twist yarns by cyclical stress fluctuation was developed. The forming principle was introduced to analyze the formation process of false twists on rotary threaded contact surfaces. Geometric analysis indicates that cyclical stress variations produce extra rotations (false twists) on fiber strands in the yarn formation area, causing twist redistribution and fiber arrangement remodeling with the appearance of local fiber reversion. Theoretical analysis reveals that more false twists are produced when the spun yarn is in contact with surfaces of high traverse speeds. Then, a motion simulation model using different traverse speeds of the threaded contact surface was established to compare the yarn internal stress variation, verifying the false-twist efficiency at different traverse speeds. Finally, a systematic comparison was conducted between the yarns spun at different traverse speeds. It was shown that the yarn properties improved with higher traverse speeds of the threaded contact surface, achieving less hairiness, high yarn strength, and low residual torque.

Study on the influence of the cotton storage process on the quality indicators of fiber and yarn

This article defines fiber quality indicators that differ in laboratory conditions from the upper, middle and lower layers of Bukhara-6 breeding varieties of cotton, in the modern system HVI 1000 SA. Based on the results of the study, histograms of changes in the quality of cotton fiber in the layers of the harem are presented. As an alternative, the quality indicators of yarn obtained in the laboratory spinning device “Sherli” of small size from fiber were determined. As can be seen from the analysis of the test results, it was found that the comparative elongation strength of cotton obtained from the lower layer of the stack, the upper average length, elongation at break, the light output coefficient, decreased compared to other layers of the stack, on the contrary, the index of hip fibers, increased, decreased compared to other layers of the stack. In addition, according to the results of the tests obtained, the fiber viscosity index was obtained – the correlation between the properties of fibers and the properties of yarn, the thread viscosity index was estimated by the CSP (COUNT STRENGTH PRODUKT) coefficient, which was determined by the formula for carded yarn obtained in the laboratory spinning device “Sherli” from fiber stored in the refrigerator. The obtained results showed that the relationship between fiber properties and yarn properties due to the fact that the maturity index of a thread is at the top of the stack compared to the middle and lower part of the stack.

Development of Sustainable and Functional Fabrics from Recycled and Nanocomposite Polyester Fibers

Antimicrobial knitted and woven fabrics were developed from recycled polyester (PET) and silver nanocomposite (SNC) fibers. Two different fabrics were produced from two different blend proportions of the fibers. The antimicrobial properties of fabrics were tested against those of the S. aureus (Gram-positive) and E. coli (Gram-negative) bacterial natures, and their yarn properties and hand-related characteristics were investigated. The results show uneven fabrics properties such as irregularity in thickness and SNC-recycled PET fiber ratio increase, and the tensile strength decreases while the NEP number increases. This implies that fabrics made from a blend with higher SNC-recycled PET fiber ratios have higher surface roughness levels, higher bending rigidity, and harder texture. As a consequence, the antimicrobial efficiency of the fabrics was improved as the percentage of SNC increased. The recycled PET fiber within the blended yarn shows a good antimicrobial property (above 90%) observed in all fabrics. The reduction of bacterial colonies was constantly exceeding 90% for both E. coli and S. aureus in all fabric samples.

Determination of suitable traveller for definite yarn count: A comparative study

The traveller imparts twist to the yarn and enables winding of the yarn on the cop. Yarn quality parameters can be improved by proper traveller weight selection which results in reducing yarn breakage, mass variation, twist variation and hairiness. High contact pressure (up to 35N/mm) is generated between the ring travellers during winding, mainly due to centrifugal force the pressure includes strong frictional forces which in turn lead to significant generation of heat. This is the kernel of the ring/ traveller problem. The low mass of the traveller does not permit dissipation of the generated heat in the short time available. Uster Evenness Tester 5 was used to determine the yarn properties such as unevenness, percentage, imperfection index, hairiness, standard variation of hairiness. Traveller number 5/0 was the best for card 30 Ne compare between traveller number 4/0 Most preeminence fact is that, the traveller speed remained same both for 5/0 and 4/0.

Numerical and experimental approach towards an energy-efficient compact spinning system

Compact spinning with a lattice apron has recently become a very attractive approach for pneumatic compact yarn production spinning systems. One of the main challenges with use of this method is the high negative pressure that leads to high energy consumption. In response to this challenge, we present a numerical and experimental investigation of the effects of a three-dimensional (3D) printed guiding device on the airflow characteristics and yarn properties. Initially, the 3D numerical model of the compact spinning system was set up based on the real geometrical dimensions. Secondly, the 3D prototype was developed, simulated, and analyzed using Solidworks and Ansys. Ultimately, the design, which exhibited low negative pressure along the model domain, was adopted and then 3D printed to enable further experimental investigation. Airflow analysis results illustrated that when using the guiding device with low negative pressure, the active area of negative pressure was increased. This was due to the existence and the special design of the guiding device that prevented the decrease of the negative pressure with atmospheric pressure. This increased the transverse condensing force, which was beneficial for twisting the free-end fiber around the fiber bundle. Experimental results revealed that the three yarns spun with the guiding device achieved significant energy saving when the guiding device was used. Moreover, these yarns spun with the guiding device had better strength, hairiness, and evenness than those spun without a guiding device. The model developed can be further improved and utilized for commercial purposes, as it significantly reduces energy costs while improving yarn properties.

Comparison of the airflow characteristics and yarn properties between conventional and dual-feed-opening rotor spinning units

In order to explore the differences between conventional and dual-feed-opening rotor spinning units (RSUs), this work compares the airflow characteristics of two RSU models utilizing a computational fluid dynamics simulation model with the accuracy verified by airflow behavior observation and air pressure measurement. The effect of two different opening roller speeds on the airflow field distribution of a dual-feed-opening model is also investigated. In addition, the yarn properties of six pure and blended yarns corresponding to the two RSU models are evaluated. The results reveal that the distributions of airflow velocity vector and air pressure in the two RSU models show a strong similarity under the same boundary conditions. However, the dual-feed-opening model possesses a centrosymmetric and more balanced airflow field distribution compared to the conventional model. In addition, the dual-feed-opening yarns show a superior performance in comparison to the conventional yarns. Furthermore, for the dual-feed-opening model, there are equivalent contributions of two separated opening and fiber transmission systems to the airflow field distribution and yarn formation. Compared to the configuration with the same two opening roller speeds, the dual-feed-opening model configured with two different opening roller speeds obtains an improved blended yarn performance with having few effects on the airflow characteristics. This strength of the dual-feed-opening RSU could facilitate the production of blended and fancy yarns employing the fibers with diverse properties. This study could provide some guidelines for the manufacture of rotor-spun yarns and the future design of RSUs.