The short and medium-sized fragments produced in the spinning process will have an adverse impact on the production of subsequent processes, causing more breaks in the weaving process, making it difficult to improve production efficiency, and at the same time affecting the quality and style of the cloth surface. So minimizing detail is especially important.
01 The generation mechanism of details
(1) During the drafting process, the fiber is subjected to Due to the influence of various factors, the fibers do not change speed on the same interface, resulting in distance deviation. If in the drafting zone, there are more fibers on a certain section of the sliver that change speed in advance, there will be thick spots, and behind the thick spots there are details; conversely, if there are more fibers that change speed later, there will be Produce details, and behind the details are the thick spots. When the fiber speed change positions are more dispersed, the shift deviation value is larger and the coarse details are more.
(2) After the roving enters the drafting zone, the fibers are subjected to various forces. The ideal state is that these forces never change, and the equipment status remains consistent, so that the strength of each fiber The shifting points tend to be the same, but the actual situation is that there are more or less differences. Controlling and reducing this difference is the goal and direction we must work hard to achieve.
02 Factors that produce details
(1) Front drafting area, where fibers are The movement is the most intense, and the state of the rollers and rubber rollers directly affects the movement of the fibers. Factors such as roller bending, shaking, poor tooth shape, excessive clearance in the iron shell of the front rubber roller, grooves and roughness on the surface of the rubber roller, large or small cradle pressure, etc. will cause continuous changes in the control of the fiber. It is easy to generate 8 cm mechanical waves; the surface of the rubber roller is rough, and fibers are easy to adhere to the surface of the rubber roller, causing fibers to be lost and details to be produced.
(2) Mid-area drafting. If the fiber is not properly controlled in this area, the movement of the fiber between the upper and lower apron will be irregular and displacement will occur. For example, the floating area is too large, the upper and lower aprons are cracked, the upper and lower pins are deformed, the surface is not smooth, the surface of the middle iron shell is rusty, flowers are accumulated in the apron, the apron is off track, the lower apron tension frame spring fails, etc., these will cause the skin to fail. The rotation speed of the loop is uneven, causing the apron to buckle, so that the yarn conveyed from the rear roller jaws cannot be effectively stretched and is twisted; the deformation of the upper pin can easily cause the upper apron to arch, causing the fiber to move between the upper and lower apron. The loss of control will produce a 30-40 cm mechanical wave; an excessive floating area will increase the number of floating fibers, causing the fiber’s variable speed position to be disordered and produce details.
(3) The traverse device is defective (less than 5 mm) or the entire device fails and does not move left and right, causing the fibers to continuously stretch and rub at the same point without restoring elasticity. Over time, grooves will appear on the rubber rollers and rubber rings, which will affect the movement of fibers during the drafting process.
(4) The upper pin spring pressure is improper. If it is too small, the upper pin will float and become unreliable, and lose control of the fiber; if it is too large, the upper pin will lose its elasticity. The action of the jaws can easily produce hard heads.
(5) The deviation of the position of the yarn guide bell will cause uneven stress on the fibers in the whiskers, resulting in details.
(6) The front draft gear is in poor condition. The front, middle and rear rows of rollers are all driven by gears. The condition of the gears directly affects the stability of the roller rotation. The wear of gear teeth and loosening of keys will directly generate mechanical waves. The middle zone generates 30-40 cm mechanical waves, and the rear zone generates 1-2.5 m mechanical waves.
(7) During the handling and use process, the surface of the roving becomes fluffy, and the fibers are lost, resulting in thick details.
03 Improvement Measures
3.1 Process Aspects
(1) Under the premise of ensuring that no hard ends are produced, appropriately using a larger twist coefficient of roving and a smaller post-draft of fine yarn can enhance the internal friction field between fibers and stabilize the friction boundary of the draft. It is beneficial for the fiber to change speed when approaching the jaws; using a smaller jaw spacing can increase the friction boundary strength of the rubber ring drafting area, which is beneficial to the control of fiber movement and stabilizes the fiber speed change point.
(2) Appropriately shortening the length of the floating zone can reduce the number of uncontrolled short fibers in the floating zone. At the same time, the friction boundary of the apron jaws can be stretched forward correspondingly, increasing the friction length of the fiber in the apron part, thereby strengthening the control of floating fibers.
3.2 Rubber rollers and rubber rings
(1) According to Variety requirements, strengthen the reasonable selection and daily management of rubber rollers. For varieties with pure cotton or cotton as the main component, soft elastic rubber rollers should be used.
(2) Strictly set the rubber roller and strengthen the rounding and shaping of the rubber roller to eliminate the stress difference of the rubber roller and improve the inherent quality of the rubber roller; do a good job of fine grinding , reduce the deformation difference of the rubber roller’s eccentricity, concavity, and big and small heads, and the rubber roller surface is smooth; for the medium hardness rubber roller, on the premise of ensuring a certain winding resistance, the paint ratio should be larger, which will help reduce rough details. of production.
(3) The apron must be soft, with small elongation, uniform thickness, accurate specifications and dimensions, good elasticity on the outer surface, and smooth and wear-resistant inner surface. The matching method of “old on top and new on bottom or new on top and old on bottom” ensures that the friction and rotation of the upper and lower aprons are stable and there is no speed difference.
(4) In daily production management, the on-duty lathes and rubber roller maintenance workers should carefully check whether each rubber roller and rubber ring is damaged or cracked, and replace them promptly if any abnormalities are found. . Replace rubber rings regularly.
3.3 Equipment aspects
(1) Front roller dynamic bending control Below 0.03 mm, the roller surface is required to be smooth and without damage, and the teeth�No dust accumulation, use a copper wire brush to clean the three-row rollers every sweeping cycle.
(2) Correct and clean the upper and lower pins to ensure they are smooth and free of burrs. The upper pin should be elastic, solid, and free of deflection to form an effective jaw.
(3) Calibrate the cradle pressure regularly to ensure that the pressure is stable and the three rows of rubber rollers are parallel.
(4) Strengthen the use and management of the traversing device. The yarn guide stroke is required to be between 8-10 mm, and the edge clearance is not less than 2.5 mm, so that the fiber can be Continuously changing the drafting point and holding point during drafting will help extend the service life of rubber rollers and rubber rings.
(5) Ensure good gear meshing, strengthen the maintenance of the keyway and keys of the shaft, and check the wear of the gear surface.
(6) During the handling and use of rovings, avoid strong friction between the rovings and prevent them from directly holding or placing the roving surface with your hands.
04 Conclusion
The above measures can be taken in the spinning process to effectively Improve equipment status, stabilize and control the fiber speed change point position during the drafting process, and reduce the occurrence of details.
(1) Focus on the use and management of rubber rollers and aprons, reduce the differences between rubber rollers and aprons, and give full play to the best performance of rubber rollers and aprons. .
(2) Strengthen equipment maintenance, perform regular calibration, daily maintenance and maintenance of rollers, upper and lower pins, traverse devices and head gears, and strictly implement workmanship.
(3) It is necessary to continuously improve the technical quality of the on-duty lathes, requiring the on-duty lathes to recognize the status differences of various components in the drafting area and provide timely feedback. At the same time, strengthen the management of picking up and placing rovings to prevent rovings from fluffing. </p
