Comparative study of viscose yarn properties spun with a softening device and pressure plate

The multi-principle drafting device is investigated to improve the comprehensive properties of ring spun yarns. In this study, the front gathering area on the multi-principle drafting device was mathematically modeled to analyze the effects of inlet width, outlet width and path length of the grooved collector on friction forces. The numerical analysis results demonstrate that the outlet width and path length play important roles in frictional forces, while the variation of the inlet widths has little effect on the friction forces. The experiment results also reveal that for 18.4 tex yarns, different outlet widths of the grooved collector have considerable influence on yarn tenacity and hairiness, whereas they show an insignificant effect on yarn evenness and imperfections. Moreover, the effects of process parameters (different roller gauges and break draft ratios) on the novel drafting device with an optimized grooved collector to spin 18.4 tex yarns were investigated by response surface methodology. The results indicate that although the break draft ratio and front roller gauge create significant effects on yarn unevenness, the back roller gauge has no apparent influence on it. In addition, response surface methodology predicted the minimum yarn unevenness of 10.71% under optimal conditions of 1.2 break draft ratio, 32.5 mm back roller gauge and 17.5 mm front roller gauge, which is very close to the experimental result of 10.57%, reaching an advanced level compared to Uster Statistics 2018 of 5%.

mentioning

confidence: 99%

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confidence: 99%

Numerical analysis and experimental investigation of a multi-principle drafting system in ring spinning

Quan

Cheng

et al. 2022

“…In addition, the fiber stiffness with soft spinning can be considerably reduced by high-temperature treatment to enhance the fiber transfer rate. 12,13 Simultaneously, exposed fibers with low rigidity will be rewrapped on or into the yarn through synergism with the gripping force. However, in addition to the extra energy consumption, the safety risks involved with thermal treatment cannot be ignored.…”

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confidence: 99%

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

Gao

Fan

et al. 2022

Self Cite

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.

“…Chen et al 22 developed a new drafting system where the top apron extends into the back zone, which gives improved fiber guidance for short fibers and an improvement in the yarn evenness. Liu et al 23 introduced a collaborative control method to improve yarn performance by contacting the spinning strand with both a softening device and pressure plate, which reduces the rigidity of fibers and leads to a reduction in yarn hairiness. Cheng et al 24 presented a new drafting device, replacing double aprons with a lattice apron and adding an air suction slot, which aims to solve the problems of double apron draft device.…”

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confidence: 99%

“…Liu et al. 23 introduced a collaborative control method to improve yarn performance by contacting the spinning strand with both a softening device and pressure plate, which reduces the rigidity of fibers and leads to a reduction in yarn hairiness. Cheng et al.…”

mentioning

confidence: 99%

Numerical simulation of dynamic pressures on a novel drafting system and experimental study on yarn properties based on friction fields

Quan

Cheng

et al. 2021

The friction fields of a novel drafting device based on the ring spinning frame are investigated in terms of numerical simulation and experimental studies. In numerical simulation, the results demonstrate that the dynamic pressure distribution in the drafting zone is presented in the form of wave undulation in the main drafting zone. Besides this, the pressure peak greatly increases close to the front nip. The effect of different spacers and middle roller speeds on the pressure distribution was also simulated, which indicates that the dynamic pressure decreases strictly with increasing spacer size, while at middle roller speeds of 0.18 rad/s and 0.26 rad/s the pressure distributions only show a significant difference at the pins nip and not throughout the drafting zone. For experimental studies, the friction fields of the novel drafting device were tested with different spacers. The peaks of the friction field decrease with the increasing spacing in the main drafting zone. The friction force shows a wavy undulation in the direction of the middle roller nip to the front roller nip, and there is also a great increase in the peak of the friction force near the front roller nip. Analysis of the properties of the three yarns spun by the novel draft device under different spacers shows that changing the spacer affects the friction forces of the drafting zone and has a significant effect on the yarn evenness, imperfections, and strength, but not on the hairiness.