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Improve the drafting conditions to make the yarn even and smooth

Update:29-07-2020
Summary:

We know that the function of the spinning process apron […]

We know that the function of the spinning process apron is to generate a certain friction force through the direct contact between the working surface of the upper and lower aprons and the yarn sliver, which can effectively prevent the premature speed change of the fiber and stabilize the control of the fiber, so that the distribution of the speed change point is concentrated towards the jaws. Reduce the floating area and improve the drafting conditions to make the yarn even and smooth

In the matching of aprons, it is better to use the upper flat/lower inner inner group (in the matching aprons, we use a new set of used ones, and it is forbidden to use new aprons at the same time for all upper and lower rings of the same variety). According to the above data analysis, the inner surface of the upper apron is rubbed against the small iron roller, and the upper apron and the spinning are moving forward with the rotation of the lower roller apron. When the upper rubber ring runs under normal conditions, the upper part is tight and the lower part is loose. Those who have experience in using rubber rings think that when using flat rubber rings, air cannot enter between the iron roller and the rod. If the running time is long, it will cause the rubber ring to stick to the small iron roller or the rubber ring and the upper rod to rotate. Inflexibility, resulting in poor yarn evenness. We found that the upper pin was easily "gnawed" by the apron when using the inner pattern to top the ring. According to the analysis, the upper pin has a small curvature radius at the front mouth, and the friction coefficient is large when the inner pattern apron is used. This will cause the above phenomenon to occur on the upper jaw, especially at a point at the jaws, where the jaws receive greater resistance, which will make the tight edges of the upper rubber ring tighter and looser edges. If the jaws receive large resistance and resistance changes during operation The big influence is that the surrounding arc of the jaw rubber ring is at the end of the range of friction force. The fiber leaves here and enters the floating zone. The friction force boundary fluctuates greatly, which has a greater impact on the quality of the yarn. The above phenomenon is not easy to occur with the inner flat apron, and the yarn quality is relatively stable. When the inner pattern apron of the lower apron is in knurled contact with the surface of the middle roller, the inner pattern apron is in contact with the flat apron. Due to the uneven pattern on the inner surface of the lower ring, the inner pattern apron meshes with the knurled groove on the surface of the middle roller. The running slip rate between the middle roller and the middle roller is significantly reduced, which greatly enhances the uniformity and stability of the synchronous operation of the lower ring and the roller. Thereby, the uniformity of the running linear speed can be improved, and the lower apron can run smoothly and evenly with the lower roller according to the process design to a greater extent, and the yarn quality can be improved.

 

The influence of apron jaw technology on yarn quality

The apron jaw process affects the friction force boundary, distribution strength and stability of the apron jaw part, and is sensitive to the characteristics of fiber movement. The size of the jaws of the rubber ring should be determined according to different varieties and different numbers. The spacer should be small rather than large, and the size should be moderate. The size of the apron pliers is particularly important for strengthening the frictional force in the apron drafting. Strengthening the pressure in the middle of the rubber roller plays an important role in the grip of the fiber and the control of the fiber in the floating zone. The speed change of the fiber movement in the floating zone mainly depends on the control force and drafting force. In order to prevent the fiber in the floating zone from changing speed earlier, the control force must be strengthened. The size of the rubber ring jaw determines the control force. Spacers of different specifications Decide the length of the apron jaws. If the spacer size is small and the jaw length is short (low opening height), the gripping force of the apron jaws will be strengthened; the spacer size is large, the apron jaw length is long, and the apron jaws Poor ability to hold fibers. Therefore, the ability of the apron jaws to control the fibers changes proportionally with the size of the spacer block. The length of the upper and lower aprons to the fiber holding surface is also very important in controlling the fiber. The gap between the apron jaws is too large, the gripping surface fiber is short, the length of the floating area is increased, and some fibers are out of control, which is not good for the yarn evenness. The apron jaws are small but moderate. If it is too small, the control will be strengthened. , But in the case of temperature and humidity changes, roving twist and roving quantitative changes, changes in the drafting force of the front cot, slubs and hard ends are prone to appear, so a small floating zone length and small aprons should be used in the spinning process. The two small processes of the jaws are one of the important measures to improve the quality of the yarn.

Use management of rubber ring

There are three main elements in the application of aprons: one is to select the type and to select good varieties that meet the requirements of spinning quality; the other is to improve the quality of maintenance and to ensure the needs of use; the third is to use management to reduce the incidence and occurrence of differences through scientific management The best performance of the rubber ring. There are three main aspects to the operation management of aprons: improving the consistency of the stable aprons in the use process, reducing the impact on uneven yarn quality; ensuring the consistency of the relevant drafting components, and reducing the impact on the normal operation of the aprons; reasonable Carry out cost management and improve the technical value of equipment. The quality of the apron use management plays a vital role in the quality of the yarn. We must pay attention to the management of the apron. The apron is a fine rubber product. Whether its performance can be used and played consistently is affected by the state of use. If the uniformity of the aprons is poor when spinning the same batch of yarn, it will not only cause the deterioration of the yarn quality, but also seriously affect the uniformity of the yarn quality between the spindles and stations, causing the spindle and table differences to fluctuate greatly. The purpose of the use and management of aprons is to control the degree of influence of the aprons in poor conditions, pay attention to the influencing factors of the consistency of the aprons in use on the uneven quality of the yarn, and take measures to minimize this problem according to the environmental conditions in use. The degree of influence of the factors must be achieved in the use process; different models, different structures, different specifications, different degrees of new and old, different surface treatments, and different hardness of aprons must not be mixed.

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