Simulation on the fiber arrangement and distribution in the drafting zone

Roller drafting is an indispensable and fundamental procedure in attenuating the sliver to an adequate linear density during the spinning process. In this study, the drafting dynamic process was reflected in the arrangement containing hooked fibers and straight fibers, and the fiber straightness in the drafting zone in real-time. The drafting process was implemented from the initiation of the sliver head moving into the drafting zone to the achievement of the straightening process for all fibers in the sliver. The developed model demonstrated that the simulated weight distributions of various fibers, including the total fibers, back fibers, front fibers and floating fibers, were more in line with the actual results than the simulative ones based on the previous drafting model with the simulation of the straight fiber arrangement in the sliver. In conclusion, the drafting model with the application of the hooked fiber arrangement was effective and precise in quantizing the drafting process of a sliver with many hooked fibers, such as a cotton card sliver. Moreover, the drafting model can offer the theoretical foundation for setting the drafting parameters from the perspective of the distributions of slow-floating fibers and fast-floating fibers.

Observation of Damage of Cotton Fiber in the Processes of Blowing, Cleaning and Carding

The quality of the produced yarn mainly depends on the properties of the raw material, its preparation for spinning, the condition of the equipment, and the preservation of the natural quality of cotton fiber during processing. The question of the number of defects in cotton fiber and their total content is a very important issue for cotton spinning. The non-standardized number of defects in the raw material reduces the quality indicators and yarn yield, which requires additional technological processes; therefore, on the part of production, the requirements for reducing the share of cotton fiber defects are constantly increasing. During processing in blowing and cleaning units and on carding machines, the cotton fiber is mechanically damaged. To observation the damaged fibers, we used the Congo-Roth red paint according to the method of Ch. Dore. Despite the carding is considered the last stage in the process of cleaning the fibers from impurities and defects in the spinning system, 30% of impurities and fiber defects still remain on the card sliver. Besides, it should be noted the carding machine is also considered an additional occurrence of defects, in particular (neps), which reduce the quality indicators of the card sliver and the finished product.

Effect of Humidity on Nep Movement in Electrostatic Field

In order to study the effect of humidity on nep movement in electrostatic field, a self-made experiment instrument was made. By this instrument, under the several kinds of different humidity, fiber neps and SCNs (seed coat neps) gotten randomly from card sliver or raw cotton were laid on down-pole-plate and then the up-pole-plate voltage was increased gradually. The voltages when the neps leaving the down-pole-plate were recorded. With statistical method, the take-off voltage averages of different kinds of nep under different humidity were calculated. It can be concluded that charging time of neps decreases largely and the take-off voltages of neps also reduce with the increase of air humidity in certain range.

Research of Relation between Card Sliver Quality and Yarn Quality

To research relation of card sliver quality and yarn quality, influence degree of card sliver parameters on yarn quality was analyzed through gray incidence analyses method and least square method, the concrete formula was got, it is feasible for production to adjust carding processing in time, enhance yarn quality stably.

Test Reliability of Impurity Parameters of Uster AFIS

This paper presents test reliablity of Uster AFIS for impurity test by calculating the Reliable Test Time (hereinafter referred to as RTT) and CV% of test results. The CV% value of test results of impurity-related parameters in card sliver obtained in 8 experiments totally with 313 different plans were calculated. By statistical analysis method, the reliable test time of AFIS for some impurity-related parameters was estimated. It is concluded that the impurity result obtained by 10-time tests with AFIS was inaccurate. The reasons for this are that the sample weight is too small, the impurity is unevenly distributed and the impurity in card sliver may have some loss in the manually-sampling process.

Effect of Electrostatic Web-Cleaner on Card Sliver Quality

To find out the effect of the electrostatic web-cleaner installed on the front plate of carding machine on card sliver quality, the sliver produced under different voltages and gauges of electrostatic plate was tested with Uster AFIS. The results show that card sliver quality can be improved when the gauge and voltage are appropriate. When the gauge is 1 mm, parameters of short fiber content, nep content, impurity content are better at a voltage of 1500 V than those of other voltages; when the gauge is 2 mm, a voltage of 500 V or 3500 V is advantageous to improve the comprehensive quality of card sliver (except for impurity content parameter); when the gauge is adjusted to 3 mm, the impurity content is decreased at 1000 V and the nep content is decreased at 2500 V, but the improvement on card sliver quality is not perfect.

Study on Front Web Cleaner Suction Form of Carding Machine

Effect of web cleaner on front plate suction form of carding machine on the quality of card sliver was studied. The card slivers processed by carding machine with web cleaner installed on the front plate using single and double sides suction forms were tested by Premier aQura. The results show that, when the suction volume is between 120~240m3/h, the range of short fiber content in card sliver is 12.03~14.0% in the single side suction and is 15.6~16.8% in the double sides suction; 5% length of fiber in card sliver is between 34.03~34.04mm in the single side suction and is between 33.64~33.83mm in the double sides suction; effective length of fiber in card sliver is from 29.71mm to 29.80mm in the single side suction and is from 29.52mm to 29.55mm in the double sides suction; total neps in card sliver is between 51~55cnt/g in the single side suction and is between 57~59cnt/g in the double sides suction. Thus it can be seen that under the same suction volume, the front web cleaner with single side suction is more beneficial to improving the quality of card sliver, so it is better for the front web cleaner to use single side suction form.