The benefits of using a saw-tooth lint cleaning machine to the gin factory have been described before, but the damage to cotton quality caused by the traditional saw-tooth lint cleaning machine cannot be ignored. The lint cleaning process reduces the impact on cotton fibers. Damage has always been the most concerning issue for textile mills. Many technicians, especially many textile experts, believe that the emergence of lint cleaning machines has not only failed to improve cotton quality, but has had a negative impact on cotton quality.
(1) Side Effects of Lint Cleaning Machine
1. After being cleaned by a sawtooth lint cleaning machine, there will be an increase in defects that cannot be eliminated. Impurity removal and carding have always been completed by two processes: blowroom and carding in textile production. . According to different linear densities and different product qualities, cotton spinning enterprises achieve the purpose of controlling product quality by setting the number of openings and blowing methods in the process. In order to prevent impurities from breaking, they usually arrange loosening and free blowing first, and then arrange the holding blow. . The saw-tooth lint cleaning machine violates this principle of cleaning and carding. It mainly uses holding and blowing. Although the impurities in the raw cotton are partially removed, the coarse impurities are broken into many small impurities, small white stars and Neps, cords, etc., and impurities and defects such as stiff pieces, soft skin and neps, which are also difficult to remove in the carding machine, not only cannot be reduced, but increased after cleaning by the lint cleaning machine. As a result, after the lint cotton cleaning machine was cleaned, although the impurity content rate decreased, the total number of defects per 100 grams increased sharply, and neps and cords increased significantly, resulting in an increase in spinning neps and impurities.
2. The use of sawtooth lint cleaning machine is not conducive to the quality of ginning.
The use of lint cleaning machine can only cover up the shortcomings of the appearance of cotton and cannot improve the quality of ginning. In actual work, cotton processing companies will relax For the cleaning of lint, sometimes even some of the lint cleaning and impurity removal equipment is cancelled, the ginning speed is increased, and the heavy responsibility of covering up the poor quality of the ginning process is transferred to the lint cleaning machine. Although this can save ginning costs and improve economic benefits, it The quality of raw cotton has dropped significantly.
3. Damage various length indicators and specific strength of cotton
Saw-tooth lint cleaning is to fully comb and remove lint fibers through the cooperation of saw-tooth rollers and debris removal knives. In the process of picking up fibers, It is very easy to break the fibers. Tests have shown that compared with uncleaned lint, the main length of cleaned lint is reduced by 0.3 to 1 mm, the quality length is shortened by about 1.5 mm, and the short lint rate increases by more than 2%. In the cleaning process of the textile factory, short lint will become As the times increase, the breaking strength of the fiber also decreases. This is mainly because the lint is hit by the licker-in roller in the lint cleaning machine, and some fibers are damaged, and some are even broken. Some damaged fibers are broken when they are hit again during textile processing, especially in the carding process, forming Short velvet.
The loss of these indicators of lint has direct harm to the textile process. On the one hand, it will cause the yarn dryness to deteriorate, the hairiness to increase, and the single yarn strength to decrease; on the other hand, during the spinning process, the shedding will increase. The amount of cotton increases the cost of spinning. In the past, the main body length of most Xinjiang cotton was in the long range of 29mm. Now, after cleaning by the lint cotton cleaning machine, the main body length is in the short range of 29mm. This not only destroys cotton resources, but also affects the textile performance.
4. Increased foreign fibers and color defects
In the lint cleaning machine, some fibers will be broken after being hit by the licker-in roller, and foreign fibers will also be broken, because foreign fibers and colored fibers have fine and Due to their long and light characteristics, the fibers are more easily broken and broken than cotton fibers during the cleaning process, thus increasing the number of foreign fibers and color defects, making it more difficult to sort in textile factories.
Due to the above reasons, many textile factories in Xinjiang, my country are trying to use contracts to specify that lint cleaning is not required or only partial cleaning is required to reduce the short fiber rate.
The country has proposed that from January 1, 2004, the cotton quality requirements for the mandatory national standard “Cotton Fine Staple Cotton” will be added
to add two new indicators – short fiber rate and neps. Although it has not been implemented due to various reasons, the “Instrumented Inspection of Cotton”
(draft) puts forward requirements for neps and short fiber index, which shows that the ginning process must be strict during ginning and unreasonable lint cleaning must be controlled. It is a general trend to reduce the damage to fibers caused by lint cleaning.
With the increase in the cost of manual cotton picking and the improvement of machine cotton picking equipment, in the near future, our country will also fully promote machine cotton picking.
Since machine-picked cotton contains a lot of impurities, it must go through two or more lint cleanings. Therefore, it is impossible to cancel lint cleaning. Reducing the damage to fibers caused by lint cleaning is the direction of our research.
(2) How to reduce the damage to fibers caused by lint cleaning
1. Use the lint cleaning machine flexibly
(1) It should be used flexibly according to the impurity content of the lint. When the cotton is relatively clean, lint cleaning does not need to be performed. For example, manual picking of cotton can avoid or eliminate the process of lint cleaning machine; pay close attention to the impurities in the lint. If the impurity content is high, the grade of the lint may be reduced. , the lint cleaning machine can be started.
(2) It should depend on the quality requirements of the textile mill for cotton. At this stage, the scale and product grades of textile enterprises are rapidly extending to both ends, and product varieties are also diversified. Different companies, different product grades and product varieties have different requirements for cotton. This requires the upstream enterprises of textile production – ginning mills to also diversify their products.
Generally speaking, the products produced by large enterprises are of higher grade and have complete testing and testing equipment. When purchasing cotton, they focus on the intrinsic quality of cotton. The products of small enterprises are of relatively low grade and have limited testing equipment and have higher quality requirements for cotton. Focus onAppearance quality and price; ring spinning has higher requirements on cotton grade, length, micronaire value, impurities, three filaments, and defects. Open-end spinning has higher requirements on various aspects of cotton due to the spinning principle and high linear density of spinning yarn. The requirements for this index are relatively low; combed yarn has higher requirements for neps and short staple ratio, and carded yarn has lower cotton quality requirements than combed yarn; the cotton used in blended yarn has lower requirements than pure cotton. Some; knitting yarns have higher requirements for cotton than woven yarns; bleaching yarns have strict requirements for “three silks” and oil-stained cotton when selecting cotton, printing yarns have the lowest requirements for cotton compared to other yarns, and dark-dyed yarns are mature for cotton. Degree requirements are very high. If the appearance quality of cotton yarn is required to be high, the lint cleaning machine can be used during fiber processing. If the intrinsic quality of cotton yarn is required to be high, the lint cleaning machine can be used less or not.
2. Strengthen the quality control and management of the entire cotton process
The technical content of the lint cleaning machine is relatively high, and its manufacturing accuracy and operation requirements are also strict. Therefore, the correct use and maintenance of lint cleaning machines is very important. Attention should be paid to the maintenance of processing equipment such as cotton cleaning machines and cotton gins, to reasonably control the output of the cotton gin, try to avoid the formation of harmful defects, and strengthen the quality control and management of the entire cotton process.
The three elements of raw cotton grade are maturity, color and ginning quality, which are the three conditions for evaluating raw cotton grade. Maturity and color are the intrinsic qualities of cotton, which are determined by cotton varieties and growing conditions. Lint cleaning The machine cannot change the maturity and color of cotton. It is incorrect to rely solely on the lint cleaning machine to change the appearance to ensure the quality of the ginning process and improve the grade of cotton.
3. Improve the structure of the cleaning machine to reduce damage to lint from the machine structure. Figure 10-4 is the SENTINEL sawtooth lint cleaning machine produced by Rams Company in the United States. The cotton enters the SENTINEL sawtooth lint cleaning machine from the airflow lint cleaning machine. Through the high-speed perforated airflow and the impurity separation roller, the single cotton is directly sent to the sawtooth, and is pulled and combed by the sawtooth roller. The cotton fibers and wool are pulled and combed. When the brush rollers meet, they are blown down by the bristles of the high-speed rotating brush roller, and are sent out through the lint outlet with the help of the wind force of the brush to complete the cleaning work.
Compared with traditional sawtooth lint cleaning machines, the biggest feature of SENTINEL sawtooth lint cleaning machine is that it uses high-speed perforated airflow and impurity separation rollers to send single cotton directly to the sawtooth instead of kneading the lint in a ball shape. On a low-speed running cotton collection drum, it removes the five rollers (cotton dialing roller, cotton pressing roller, drafting roller, drafting smooth roller, and cotton feeding roller) between the dust cage, the rack roller, and the brush roller. , the mechanical parts, cotton collecting and driving parts are reduced, the damage to lint is greatly reduced, and the feeding procedure is simplified, which also facilitates operation and maintenance.
Compared with the traditional sawtooth lint cleaning machine, another advantage of using this method of conveying airflow and dust is that impurities will not be squeezed into the cotton.
Ginning and cleaning are complementary to each other. Ginning is the basis for ensuring the quality of the ginning process, and cleaning is the supplement and perfection of ginning. If ginning is ignored, the quality of the ginning process will be difficult to guarantee, and if cleaning is lacking, the ginning production efficiency will be difficult to improve.
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