How To Reduce The CV Value Of Spinning Yarn Strength? How To Solve The Problem Of Breaking Holes In Cotton Web?

How to reduce the CV value of spinning yarn strength?

　 Answer: To reduce spinning strength CV, we should start with the following aspects.

1) improve yarn evenness and reduce yarn defects. At present, adopting high elasticity and low hardness cots is an important way to improve yarn quality. Through experimental research, the high elasticity, low hardness, high pressure surface free (micro) processing aluminum lining rubber cots and heavy pressure technology are combined in the knitting yarn drafting process, and combined with the upper and middle cots and the new type lower pin technology can further improve the evenness and reduce the yarn defects.

2) reduce twist CV. Yarn strength CV is closely related to twist CV. Strong twist and weak twist will cause strong and weak rings. The above mentioned factors that cause the fluctuation of spinning tension will also cause the twist of yarn. The technical measures have been described in detail and will not be repeated here.

3) to reduce twisting and twisting. As the twist of the white ring travelled upward, the twist of the white ring travelled gradually decreased. The cotton yarn is transferred downward and twisting upward upward at the guide hook, and the twisting effect is caused by the frictional resistance of the guide yarn hook. The twist of the self guiding yarn hook upward to the front roller jaw is gradually reduced due to the twisting effect. The area near the front roller jaw section is also formed by the encircling arc of the yarn bar to form a weak twisting area. The twist at the front roller jaw tends to zero to form a twisting. The dynamic strength of the yarn is weakest in the weak area near the front roller, and the spinning strength is only about 1/4 of the strength of the single yarn. The most easily broken ends here are usually called upper breakers. In order to reduce the upper breakage, the twisting and twisting must be minimized. The first step is to raise the three center precision of spindle, collar and guide hook to increase the transmission efficiency of twisting upward. The two is to increase the forward displacement of the front rubber roller properly, so as to reduce the encircling arc of the yarn in the front roller, and the three is to use the small diameter small ring smooth wear resistant guide hook.

In addition, it is also necessary to prevent the rotary spinning of the roving hanger from being small and smooth, and the yarn guide bar is not polished and uneven. The surface of the horn is not smooth, resulting in unexpected drafting of the roving yarn. To prevent the yarn from accumulating the yarn, the roving is produced by unexpected drafting; the front, middle and rear three rollers are bent, the front, middle and rear cots are eccentricity, the bearing wears and the core is not clenched. The three row roller bearings are worn out, the gap between the bearing shell and the supporting seat is compressed, and the rollers rotate flexure. These defects will deteriorate the CV and increase the details. If the front roller parts defect can produce short details, the defects of the middle or rear roller parts will have longer details after drafting. Therefore, it is necessary to strengthen the periodic maintenance management of the roller and the top roller of the cots and maintain good condition. The spindle position of deteriorated CV and serious mechanical wave should be followed up for analysis and maintenance. For conventional tests, it is found that spindles with little twist or low strength should be repaired in time.

Question two: what happens when there is a hole in the cotton net?

　 Answer: Measures to control holes in cotton net are as follows.

1) the problem of eccentricity, bending, concave, surface crushing, shell core clearance, bearing damage and so on should be replaced in time. Rollers bend is not allowed to exceed 0.05 mm.

2) the grooming passages such as cylinder, top comb, brush, separating cots and triangular airflow plate should be clean and clean without any inlays; the gap between the triangular airflow plate and the brush should be appropriate; the nippers should be replaced in time.

3) the negative pressure of the main air duct should not be too large, so as to avoid disturbing airflow due to blocking flowers or brushing the flowers in the middle of the brush. The clearance of each suction damper is adjusted one by one, and from the rear of the vehicle to the front of the vehicle gradually increases, which ensures the consistency of the negative pressure of the carding units and the smooth flow of the air. To wipe the car is to use warm damp cloth to wipe the cotton wax in the washing bucket, and then polish it with chalk dust.

4) it is necessary to avoid the holes in the cylinder and the top comb to form a hole in the cotton net. The opening of the clamp plate should not be too small. When the noil spacing is adjusted, the change of the opening amount of the clamp plate should be detected in time, and the opening of the clamp plate can be controlled at 18 mm to 21 mm when the cotton is retreated.

5) according to experience, the imported non treatment separating rubber roller needs no regrinding as long as there are no scratches, cracks, bending and concave phenomena on the surface.