Spinning yarn breakage is the main hazard in spinning production: it affects the output of the spinning machine and reduces production efficiency; it increases the labor intensity of the car stopper; it easily causes an increase in fabric defects and causes large quality fluctuations; it increases flower return and yarn return. , machine material consumption; therefore, end-breaking is an obstacle to the development of high-yield, high-quality, low-consumption, and large-package production of spun yarn.
Spinning yarn breakage can be broadly divided into two categories: breakage before the yarn is formed and breakage after the yarn is formed.
1. Analysis of end breakage before yarn formation
Before the front roller spins yarn sliver The main reasons are as follows:
1. Roving breakage: If the roving always breaks near the upper reversal, it may be due to the small twist of the roving; if The roving always breaks near the lower reversal, which may be caused by the high position of the spun yarn guide rod; the details of the roving caused by the front spinning machinery will also lead to an increase in spun yarn breakage.
2. The lathe operator has a poor sense of responsibility, is not clean, and has accumulation of bell mouth and empty roving caused by infrequent patrols, as well as rubber winding rollers caused by poor temperature and humidity in the workshop. , apron winding, roller winding, etc. to form yarn breakage.
2. Analysis of yarn breakage
Refers to the past The yarn between the roller and the bobbin is broken during the twisting and winding process. The reasons are mainly related to the following points:
1. The influence of spindle speed
As the spindle speed increases, the yarn will Increased decapitation. The reason is that when the spindle speed increases, the centrifugal force generated by the rotation of the traveler increases, and the tension of the yarn also increases, resulting in an increase in end breaks. When the spindle rotates at a constant speed, the distribution of doffing ends is: most small yarns, less large yarns, and smallest medium yarns. The ratio is 5:2:3.
After eliminating factors such as poor air conditioning, mechanical operation and cleaning work, poor bobbins, and poor roving, the causes of spun yarn breakage can be reduced by using frequency converters for speed regulation. About 30 percentage points.
2. The influence of the weight of the wire ring
The weight of the traveler affects the spinning tension size. If the traveler is too heavy, the spinning tension will be high, which will increase the friction between the traveler and the yarn, and yarn breakage will increase; if the traveler is too light, the spinning tension will be low, and the balloon will be too large, causing the yarn to hit the yarn separation plate, causing the yarn to break. Two adjacent spindles interfere with each other, resulting in increased breakage. When selecting the weight of the traveler, the following factors should be considered:
1) Yarn type
The thicker the yarn, the easier it is to As the strength of the yarn increases, the weight of the traveler should be heavier; when spinning chemical fiber, because the chemical fiber has better elasticity and is easy to stretch, under the same weight of traveler, the friction coefficient between the chemical fiber yarn and the traveler is large, and the air The ring tension is small, so the air ring is formed large and easy to break; therefore, the weight of the traveler should be 2-3 Nos. heavier than cotton when spinning chemical fibers, and 6-8 Nos. when spinning medium-long fibers.
2) Spindle speed
When the spindle speed is high, the centrifugal force and yarn tension of the yarn increase, so they should be appropriately reduced. The weight of the traveler can reduce the breakage rate.
3) The influence of the service time of the steel ring
Under the same conditions, the number of the wire ring increases with the operating time of the steel ring. Different but not the same. When a new steel ring or a repaired steel ring is put on the car, the friction coefficient between the traveler and the steel ring is large, and the traveler must be handled lightly; as the use time of the steel ring increases, the friction coefficient between the traveler and the steel ring decreases, and the steel wire The ring should be appropriately weighted; when the steel ring declines to the later stage, the track will be worn and deformed, the head will be heavy, flying rings will appear, and the number of broken ends will increase dramatically. At this time, the weight of the wire ring should be appropriately reduced. The service life of the steel ring is related to the variety structure of the yarn and the level of the spindle speed. The smaller the yarn number, the longer the service life of the steel ring; as the spindle speed increases, the service life of the steel ring will be shortened. The service life of flat steel rings is 12 months, with repairs once every 6 months; the service life of tapered steel rings is 16 months; however, with the small batches, diversification of products, and the increase in number changes, the number of steel rings has also increased. The service life cycle is shortened to: the flat steel ring is repaired once every 4 months and scrapped after 8 months; the tapered steel ring is scrapped after 13 months; in this way, end breaks can be reduced and yarn quality can be ensured.
4) The diameter of the steel ring and the length of the bobbin
When the diameter of the steel ring increases, it is mainly when winding a small diameter , the tension increases more. If a heavier traveler is used, the shape of the balloon will be straighter in the part where the large yarn is wound with a small diameter, making it easier to cause the large yarn to break. Therefore, when the diameter of the steel ring increases, the weight of the traveler should be reduced; the increase in bobbin height will cause an increase in yarn tension and an increase in the maximum radius of the balloon, resulting in an increase in breakage, so the traveler should be heavier to solve the problem.
5) Steel ring model
In practice, it is found that the selection of the weight of the traveler also depends on the model of the steel ring. Under the same conditions, the use of tapered steel ring spinning uses a heavier traveler than the flat steel ring spinning, which can increase the package capacity, reduce the number of doffing, and reduce end breaks.
3. The influence of the selection and matching of ring and traveler models on breakage
The model of the steel ring and the traveler and their coordination affect the size of the traveler yarn channel and the balance state of the traveler operation, thereby affecting the yarn breakage. In practice, it is found that flat steel rings are suitable for a wide range of yarn sizes, but in the current situation of small batches, multi-variety production, and frequent number changes, the number of ends breaks increases; while tapered steel rings can adapt to frequent number changes, but in the current situation of small batches, multi-variety production, and frequent number changes When it is suitable for spinning medium and coarse yarns, there are particularly many ends breakage when spinning fine yarns. In actual production, the model of the steel ring is generally determined and needs to be selected.Choose the model of the traveler. When selecting the model of the traveler, factors such as suitable spinning varieties, yarn thickness and spindle speed must be considered.
4. Reasonably determine the service life of the wire ring
As the steel wire The high-speed operation of the ring will cause wear to a certain extent, the coordination between the wire ring and the steel ring will be poor, the running stability will be poor, and the yarn tension will fluctuate greatly, which will increase the number of breakages; therefore, the service life of the wire ring must be reasonably determined. The service life of the traveler is closely related to the raw material, yarn number, spindle speed and winding. Under normal circumstances, the thicker the yarn number, the higher the spindle speed, and the larger the package, the shorter the traveler replacement cycle will be. In practice, it has been found that when the tapered steel ring is newly spun for medium and fine yarns, the traveler must be replaced as soon as it is spun, otherwise large areas of end breakage will occur.
5. The influence of twist on end breakage
Yarn twist When increased within a certain range, the strength of the yarn increases, which is beneficial to reducing end breakage. When the quality of raw cotton is poor, there is a lot of short velvet, poor maturity, and fine fibers, increasing the twist by about 2% can effectively reduce end breaks, but it will increase the hairiness of the yarn. Spinning derivative and traveler matching range. </p
