Cause Analysis And Control Measures Of End Breaking In Air Spinning

This paper mainly introduces the main reasons for the breakage of rotor spinning, and analyzes the causes from the different forms of broken ends, such as general broken ends, repeated breakage, partial breakage, large area breaking operation, equipment, process, temperature and humidity, raw materials and so on, and takes corresponding measures to reduce the broken ends effectively.

The breaking of rotor spinning is one of the common phenomena in the production of rotor spinning. After breaking, the yield, quality and rate of cotton yarn must be affected. The higher the breakage rate, the greater the harm. The breakage rate increases and the number of joints increases, which will inevitably cause the joint thickness and screw head to affect the yarn quality. At the same time, the broken ends are the concrete embodiment of the management level in spinning production. Therefore, minimizing breakage in production is an important way to achieve high yield, high efficiency and high quality.

01. Reasons for broken ends of rotor spinning

The main reason for the breakage of the spun yarn is the weak strength of the yarn in the process of condensation and coalescence. The spinning speed of the rotor spinning machine is very high, the centrifugal force is large, and the negative pressure in the spinning cup is very high. Therefore, the air resistance in the spinning process of the spinning cup is larger. When the fiber bundle is stripped away from the condensate tank at the cotton sliver stage, its ability to resist scratching is very poor at this time because of its little twisting. If the strength of the fiber bundle is less than the tension formed by the frictional resistance, air resistance and centrifugal force in the spinning cup, the yarn will produce a broken end.

Practice has proved that most of the broken ends of the spun yarn yarns occur in the sliver section between the stripping point and the false twist head. It can be divided into two kinds: twist before break and twist after break. The main reason for the breakage before twisting is that during the process of condensing and merging, the fiber arrangement is damaged by different forces, leading to advanced or delayed motion. The emphasis is on impurities, dust, dead cotton bundles and instability of operation and negative pressure in cotton sliver. After twisting, the breakage is mainly caused by the loss of twist, the twist and the twist of the yarn.

02. Analysis of the influence of rotor spinning on broken ends

2.1 temperature and humidity reasons

The relative temperature and humidity are large, and the cotton sliver is not easy to loose and remove impurities, which leads to breakage. The moisture regain of the sliver is controlled between 6.1%~7.2%, which facilitates the carding and fiber transfer of the carding roller to the sliver, and is conducive to twisting of the spinning cup. The moisture regain is large, which increases the difficulty of carding roller to carding and transferring cotton fibers. It is easy to hang up the ends of the carding roller to form a fiber bundle and produce a broken end.

2.2 reasons for operation

Flying flowers are attached to cotton sliver, spun and mixed with dust, excessive dust and false twist around the flowers are all factors that cause breakage. The working state of the spinning cup condensing tank has an important influence on the evenness and broken ends of the yarn. If there are many impurities and small dust clusters in the condensing tank, the distribution of fibers in the condensing tank is uneven, and the transmission of twist can also be affected. Another situation is that the spalling surface of the condensing tank is spalling due to improper use or improper use of the spinning cup, resulting in the difficulty of stripping the fibers and breaking ends. Empty cylinder, touch the top and other reasons, will also cause a certain amount of broken ends.

Reasons for equipment 2.3

The ring of the carding roller should be clean and sharp, which is conducive to the combing, miscellaneous and transfer of fibers. But in the production process, the carding roller is unavoidable to produce the phenomenon of inverted teeth and bending teeth. These curved teeth are very unfavorable to the transfer of cotton fibers, and they will gather cotton fibers to form cotton bundles, which will lead to broken ends. The false twist plays a false twist in the process of spinning and twisting. It requires that the circular surface of the contact between the false twister and the yarn and Kong Dou should be very bright and clean, so as to facilitate the formation and transmission of the twist back, and reduce the frictional resistance to the yarn and reduce the generation of the broken ends.

2.4 technological reasons

The design of the spinning speed and the yarn feeding speed will cause the breakage when the design is unreasonable. If the pressure of the cots is too large and too small, improper selection of the tension coefficient will result in a broken end. It is also a major factor to break the fiber by twisting too little and making the fibers less cohesive.

2.5 raw material factors

The raw materials used for rotor spinning are low grade cotton and part of cotton, which contain more impurities, more dust and short staple. The length of the main body is short and the strength is low. This increases the difficulty of spinning and increases the probability of broken yarn. Therefore, when other conditions remain unchanged, increasing the cotton grading can significantly reduce the yarn breakage.

03. Control measures for broken ends of rotor spinning

The breakage of rotor spinning is divided into general breakage, repeated breakage, partial breakage and large area breakage.

(3.1) control measures for general broken ends

The reason of general broken ends is accidental. It has little to do with technology, temperature and humidity. Most of them are caused by random factors. Pay special attention to control of operation equipment. Operational control measures: attention to the quality of local cleanliness, yarn flying, broken bar, empty cylinder change not timely, sliver defect and other factors caused the broken ends. Equipment control measures: mainly due to accidental factors such as vibration of the machine cause fiber condensation and timeliness of the weak ring, control when focusing on its contingency, such as cotton rollers to produce flower broken ends.

3.2. Control measures for repeated breakage.

Repeated breakage refers to two consecutive or repeated breakage of the same single spindle. The impact of this break is the most dangerous. Control focuses on process factors and equipment causes. The reasons for operation, temperature and humidity, raw material factors and cleaning effect of the spinning cup are considered when large area repeats the broken ends.

3.2.1 operation reasons control measures

In order to catch the regular defects in cotton sliver, the cleaning effect of the spinner is good, and the combing chamber is free from impurities and dust.

3.2.2 equipment causes control measures

Emphasis should be placed on cotton plate, cotton roller, carding roller, fiber channel deformation and damage, and timely maintenance.

3.2.3 raw material control measures

When the repeated breakage occurs, the dust accumulated in the spinning cup will continue to increase after cleaning. Attention should be paid to the impurity content of the raw cotton, and the proportion of mixed use of cotton should be adjusted.

3.2.4 process control measures

Too small winding tension is liable to cause repeated breakage. The negative pressure of the spinning cup keeps stable, and the pressure of the rubber roller and the leno roller is unified. The speed of the spinning cup must match with the diameter of the spinning cup, otherwise it will cause insufficient negative pressure to cause a large area of repeated breakage.

Control measures for partial 3.3 broken ends

The local breakage increased obviously, while the different varieties considered the comprehensive factors, while the local machine was mainly controlled by mechanical factors and technological factors. Raw material factors: the control of local breakage of different varieties focuses on raw material factors and reasonable selection of process. The adjustment of raw materials should be based on the number of yarns. Control of operational reasons: reasonably grasp the time of collecting impurities in the spinning cups, and clean them according to the different varieties and the rotor spinner.

The partial machine breakage is mainly focused on process control. Attention should be paid to whether the negative pressure of the negative pressure and the negative pressure of the process are reasonable, the winding tension, the roller pressure and the speed of the spinning cup meet the requirements of the process. According to the number of spinning yarns, the condition of cotton blending, the running state of the equipment and the quality of the fittings, the reasonable spinning speed and speed of the spinning cup should be selected. The yarn number is smaller and the cotton blending is relatively good. The important parts such as spinning cups, carding rollers, false twists and so on are in good working condition. At this time, the spinning speed of the spinning cup can be selected higher and the yarn speed can be higher. Equipment focus on maintenance cycle, mechanical status and effect.

3.4 control measures for large area broken ends

Large decapitation is the phenomenon of the decapitation of some varieties of machines. The main reasons for this phenomenon are the negative pressure of process, the temperature and humidity and the equipment of raw materials.

Temperature and humidity control measures for 3.4.1

The relative humidity is too high, the fibers are not easy to loose, impurities are difficult to rule out, and fiber bundles and fiber bundles are easily broken. When the relative humidity is too low, the fiber is loose and the fiber holding force is poor. During the twisting process, it is likely to cause strong weak rings, resulting in a large area of broken ends. Selection range: summer temperature is 32 ~ 33 C, relative humidity is 67% ~ 70%, winter temperature is 26 ~ 28 C, relative humidity is 63% ~ 65%, at the same time, the temperature and humidity of pre spinning are controlled reasonably, and the phenomenon of entanglement and winding in production is reduced.

3.4.2 negative pressure process control measures

Negative pressure is one of the important factors affecting the broken ends, and it is also an important factor affecting yarn quality. The influence of technological negative pressure on large area breakage is mainly related to the operation of machine exhaust and dust removal units. In actual production, impurity boxes should be cleaned up in time to prevent small wind and exhaust ventilation.

3.4.3 raw material control measures

Under other conditions, increasing the cotton grading can significantly reduce the yarn breakage.

3.4.5 process control measures

As far as possible, the cotton grabbing machine reduces the depth of cotton grip and ensures uniform mixing. Combing cotton reduces fiber damage and controls the growth of short staple. It takes into account the effect of sorting out impurities, unified noil, uniform spacing and reduced platform difference.

3.4.6 operation reasons control measures

More efforts should be made to clean up, reduce the attachment of flying flowers, and increase the catch strength of sliver defects. The truck drivers should do the cleaning work according to the prescribed time and requirements so as to keep the air outlets and passageways of the spinning machines smooth. When changing cotton sliver bucket, the sliver can not press too much to prevent sticking. On the other hand, cotton sliver should not be placed too long.

3.4.7 equipment causes control measures

The machine parts that must be contacted with cotton fibers must be clean and bright. It is necessary to ensure the sharpness of the gear ring of the carding roller and not to have the phenomenon of falling teeth. Repair and replace the spinning cup, carding roller, false twist head and cotton conveying channel according to the cycle. Regular refueling and replacement for spinning cups and carding rollers.

04. epilogue

The breakage of rotor spinning is a comprehensive reflection of various factors such as process, equipment, operation, raw material and temperature and humidity in the spinning process. Different control measures are adopted to reduce broken ends, broken ends, partial breakage and large area breakage.