Purpose, Principles, Requirements And Methods Of Cotton Blending In Cotton Spinning Process

1. The purpose of cotton blending:

1, in order to maintain the stability of production and yarn quality.

Quality and low consumption are required to maintain relatively stable production process and yarn quality. Maintaining relative stability of raw cotton is an important condition for production and quality stability. If a single mark spinning is used, when a batch of raw cotton is used up, the other batch of raw cotton must be replaced to replace the used batch. The frequent conversion of raw materials will cause fluctuations in the quality of production and yarn quality. If a variety of raw materials are used together, the quality of the blended cotton can be maintained relatively stable, so that the quality of the production process and yarn quality can be maintained. It has remained relatively stable.

Reasonable use of raw cotton, as far as possible to meet the requirements of yarn quality and yarn count, because the yarn quality and characteristics of the requirements are not the same, coupled with the characteristics of the spinning process, therefore, all kinds of yarn quality requirements for the use of raw cotton is also different. In addition, the quantity of raw cotton stored in cotton mills is small and the quality is high and low. If a raw cotton or a batch of raw cotton is used to spin a yarn, it is difficult to meet the requirements in quantity or quality. Therefore, blended cotton yarns should be used in order to make full use of the characteristics of all kinds of raw cotton and make good use of each other to meet the requirements of yarn quality.

2, in order to save cotton and reduce costs.

Raw cotton is priced according to quality. The price of raw cotton varies greatly with different fiber lengths and grades. Raw cotton investment accounts for 50%--85% in cotton yarn cost (depending on varieties). If the grade of raw cotton is higher, the yarn quality can be guaranteed, but the increase of production cost means that the profit of the yarn is reduced. Therefore, cotton blending should be controlled from the economic efficiency. Price, and the amount of cotton used per ton of yarn, and strive to save the cost of raw cotton. For example, in the cotton with shorter fiber length, proper mixing of a certain proportion of the lower grade raw cotton with a longer length will not only reduce the yarn quality, but increase the yarn strength. It can also be used in cotton blending at a certain proportion for raw cotton, feet, back flowers, combed noil, cotton and other ingredients. Low cost of cotton and saving cotton.

Two. Principle of cotton blending

The principle of cotton distribution should be quality first, comprehensive arrangement, overall consideration, and key points.

Quality first, overall planning and overall arrangement, ensuring the key point is to deal with the relationship between quality and saving cotton. On the basis of many varieties of production, according to the different quality requirements, we can ensure cotton production of key varieties and make overall arrangements.

Looking ahead and looking ahead is to fully consider the inventory of raw cotton, semi finished products, raw cotton procurement of various aspects of the situation, to ensure supply.

The best way is to extend the use period of each batch of raw cotton as far as possible, and strive to achieve multiple mark production, at least 6 to 8 marks. Through thorough analysis, the reasonable allocation is to find out the trend of cotton and the quality of raw cotton in time, and keep the feedback information of product quality at all times. Three, cotton matching requires cotton mills to produce more varieties, with different yarns, different yarn with different process and processing methods, and different yarns for different purposes, such as:

1, the number of yarns: high count yarn generally refers to more than 50 yarn, generally used in high-end products, requiring high yarn strength, less appearance defects, uniform evenness, high yarn diameter, small number of fibers contained in the cross section, easy to expose defects, and uneven distribution of fiber root number in the section, which has great influence on the yarn evenness. Therefore, cotton blending should be based. Raw cotton with different grades and qualities is selected from different branches.

2, combed yarn and combed yarn: combed yarn is generally high grade product, requiring good appearance, evenness and less neps. Combing process can eliminate short fibers and some impurity defects, and it is difficult to remove neps. Therefore, combed cotton requires raw cotton lint and neps as low as possible and low maturity, and high tax rate will easily produce neps and use as little as possible. Combed products are used for making high-grade fabrics and require higher dyeing effect. Therefore, raw cotton is selected with good color and good evenness, and sometimes it needs long staple cotton.

3, single yarn and strands: the general single yarn is backhand twist, the strand is used in the direction of twist, the angle between the strand and the spool is smaller, so the fiber utilization ratio is higher, the strength is also greatly enhanced, the evenness is improved, and the general bar level can be increased by 2 to 3%. The number of feathers and defects has also been greatly improved. The use of ply yarn is generally used with warp yarn, so the cotton grading and quality can be reduced.

4, warp and weft: the warp has many more chances of tension and friction in use, so the warp strength requirement is higher. When the cotton is used, it should be selected with a slender fiber, a single fiber with high strength, moderate maturity and good evenness. Therefore, the raw cotton is more suitable for the neps and impurities removal on the yarn in preparation and weaving process, and also through the sizing process. The color and impurity requirements are low, the weft yarn is not starched, the preparation process is simple, the chance to remove impurities is less, and the weft yarn is exposed on the surface of the fabric. Therefore, weft yarn has great influence on fabric's color, appearance, handle and other factors. However, the weft yarn is not strong enough for strength. Therefore, it can choose raw cotton with good color, less impurity, shorter thickness and less tension.

5, knitting yarn: knitwear is knitted by single or several yarns, which requires higher yarn breakage, defects, strength and dyeing effect. Knitted yarns are generally used for underwear production, requiring softness and comfort. Therefore, yarn twists are small, yarn evenness requirements for knitting yarns are very high, and yarn with uneven thickness is particularly evident on fabrics. The yarn strength, sliver, defect and breakage should be taken care of in all aspects. Therefore, we should select raw cotton with fine fiber length, good evenness, normal maturity, low short staple rate and few defects, and knitted yarn with good maturity, good elasticity and short length.

6. Dyed yarn: all cotton fabrics must be dyed and dyed after finishing. The color absorpting ability of the fabrics is closely related to the properties of the fibers. The light coloured cloth does not require high raw cotton, but the raw cotton with low maturity coefficient and large difference can not be used, otherwise it will cause uneven mixing of fibers and stain or streak will appear after dyeing, so light colored cloth requires less impurity. It has better color cotton. Dark cloth has a high demand for color absorbs and requires a good maturity of raw cotton and printed cloth to lower the requirements for raw cotton, because after printing, it can cover some yarn defects and crossbars on some cotton fabrics. For the yarn dyed yarn, the highest demand of one color fabric yarn is used. The one color cloth is also known as "Mi Tong bu", which is made of dyed yarns for high-grade decoration or clothing fabrics. Because the yarn needs to be processed and dyed by many processes in the process of dyeing, it requires yarn hairless, no yarn defects and no joint. At present, the yarn of top grade one color yarn is less.

7. Special yarn: there are many kinds of special yarns, such as tire cord, high-grade sewing thread, decorative fabric yarn, handkerchief yarn, etc. it is required that cotton should be selected according to the quality requirements, so that the phenomenon of universal cotton can not be produced.

In the yarn purchase contract, in addition to requiring spinning mills to order spinning according to yarn use, many orders also require specific quality and technical specifications of yarns, such as dry CV value, yarn nep defects, etc., in addition to production management, technological conditions, mechanical condition and operation level, the quality of cotton yarn is very reasonable. Therefore, mastering the different requirements of yarn quality to raw cotton, and the relationship between them, and giving full play to the technical performance of raw materials, will play an important role in improving yarn quality, stabilizing production and reducing production cost when the cost of cotton blending is relatively low.

Three. Cotton blending method

At present, cotton spinning enterprises generally use the method of assorting queuing, which is divided into one type according to the characteristics of raw cotton and the different requirements of yarns. The raw cotton is suitable for spinning a certain type of yarn, and the line is to place the same kind of raw cotton in the first place according to the origin, nature and color base. The advantage of the classified queuing method is that it is possible to arrange a yarn blending component at a certain stage and ensure the mixing effect. It is a scientific cotton blending method.

1. Classification of raw cotton

The following points should be considered when classifying raw cotton.

First, we can classify raw cotton according to the specifications of spinning products, for example, combing 32 - 40 knitted yarns, using the same kind of raw cotton.

Two, the composition of each cotton assorting is determined according to the specific technical specifications of raw cotton, but the difference of technical indexes of each batch of raw cotton should not be too large, for example, the control range is as follows: grade: 1 - 2 level: 2 - 4 mm impurity content: 1 - 2% moisture content within 1 - 2% package: tight package, tight package, loose bag, loose bag, close to stable place, etc.

Three, cotton spinning process is different, cotton classification should also be flexible, for example: when the same raw cotton has different yarn quality in different seasons, cotton classification should be adjusted as soon as possible.

2. Raw cotton queuing

On the basis of classification, the same type of raw cotton is arranged into several teams, and the raw cotton, which is relatively close to the technical indicators, is arranged in a team so that when the raw cotton of a batch number is used up, the cotton is replaced by another batch of cotton in the same team, so that the characteristics of the raw cotton are not changed significantly, so as to achieve stable production and guarantee the quality of the yarn. Cotton queuing should follow the following points:

Main ingredients:

In order to ensure the stability of the production process and the quality of yarn, a number of raw cotton, which is relatively close to the technical indicators, is generally consciously arranged in the cotton blending as the main component. The main component generally accounts for about 70% of the total cotton distribution, which avoids excessive mixing of raw cotton with good or bad quality. However, because the performance of raw cotton is very complex, in the specific production, if it is difficult to use a team of raw cotton as the main ingredient, we can consider using several batches of raw cotton, but pay attention to the use of Shuangfeng do not receive batch phenomenon.

Number of teams and percentage of mixed use

There is a direct relationship between the number of teams and the mixing ratio. The number of teams is large, the mixing ratio is small, the number of teams is small, and the mixing ratio is large. When the number of teams is too large, the production management is very difficult, and it is easy to cause uneven mixing. When the number of teams is too small, the mixing is relatively large. When the batches are too few, the performance of the raw cotton will be greatly different.

So when determining the number of teams, we first need to know the way of mixing cotton. If we use artificial small batch production, the number of teams is best to be less than 4 teams. When the cotton mixer is mixed with cotton, it can be increased to 6 to 9 teams.

Secondly, we should determine the number of teams, and consider the total amount of raw cotton. When cotton yarn belongs to small batch production, the number of teams is not too easy.

Furthermore, we should consider the origin, variety and quality index of the raw cotton, and we should consider the number of cotton ginning plants in the original cotton producing area, and the number of teams is more.

Finalize the number of teams and consider the variety and requirements of the product. If the color of the product is higher, the number of teams is much easier and the yarn quality fluctuates more.

When the number of teams is fixed, the percentage of mixed raw cotton can be determined according to the quality of raw cotton and the requirements of yarn quality. In order to reduce the fluctuation of yarn quality, the maximum mixing ratio is about 25%.

Process flow of raw materials for factories:

1, feed procedure: generally according to gross weight (local cotton) or net weight (import) or quasi weight (Xinjiang cotton) settlement.

2, workshop material: the General Factory is calculated according to gross weight, and the rate of production is based on the raw cotton situation: (1) air spinning: cotton assorting grade: 4----6 grade: 1.12 spinning one ton. (2) air spinning: cotton grade 4 - 6 plus foot: 1.15 - 1.2 spun ton, according to cotton distribution. (3) ring knitting: when the cotton grade is 3, 1.08 to 1.1 spun a ton. (4) ring spinning combing: when the cotton grade is 2, 1.34---1.38 spins one ton. (5) when the ring spinning combed long staple cotton high count yarn 1 - 2, 1.38---1.46 spun a ton, depending on the proportion of long staple.

3, the way of calculation:

Cotton collar in workshop -- gross weight -- total accumulated weight of monthly inventory

The workshop Stores cotton yarns --- the yarns according to the national standard -- accumulating total monthly storage volume.

The weight of semi-finished goods in the inventory workshop at the end of the month - the number of semi-finished products stored last month.

Example: in October, a factory used a total of 120 tons of raw cotton or available cotton to produce 80 tons of 10 tons, 40 tons of 40 tons, 40 tons of spinning yarn, 50 tons of cotton yarn, 100 tons of cotton yarn in all kinds of production, and 50 tons of semi finished products in the inventory workshop this month. The semi finished products were 60 tons last month. The October production rate of the workshop was [120- (60-50)]/100=1.1, and the rate of production in this workshop was 1.1 this month.

When the raw cotton can be used or borrowed from other factories, the raw material should be reduced.

In order to reduce the quality of cloth and cross gear, the difference of micron value of each batch of cotton blending fiber should be controlled within 0.4. The raw cotton trade in the international market usually takes the micron value as one of the price reference indicators, and price or discount for raw cotton which exceeds or can not reach the spinnable value of spinnability.

The strength of single fiber is also one of the main indexes to determine yarn strength. Cotton fiber must be constantly subjected to external forces during spinning. Fiber has certain strength. It is one of the essential conditions for spinning cotton fiber. Under normal conditions, cotton fiber is strong, and yarn strength is strong. Cotton fiber strength is not only related to fiber thickness, but also to cotton varieties. In order to achieve the required single yarn strength, we should pay special attention to the single fiber strength of cotton blending.

Raw cotton defects are harmful to spinning because of bad growth or poor rolling during cotton growing. Raw cotton defects are not easy to be removed in spinning process, or wrapped in yarn or attached to yarns, resulting in deterioration of the evenness, broken ends and poor appearance, which directly harm spinning production and final product quality.

The sugar content in cotton fiber refers to the general term of soluble sugar, including the physiological sugar and the exogenous substances attached to it. When the sugar content in raw cotton is too high, the phenomenon of adhesive fiber will obviously occur in carding, combing, drawing, roving, spinning and other processes, which will affect the normal production, especially the domestic new equipment gradually put into use, which is not suitable for raw cotton with high sugar content. Therefore, it is prudent to use raw cotton with high sugar content no matter how favorable the price is, especially for producing high-grade knitted fabrics.

To do well the trial spinning of raw cotton can avoid or eliminate the limitations and errors caused by sensory inspection and instrument testing. Therefore, the new batch spinning of raw cotton should be arranged before the raw cotton is put into production in large quantities, and then the new cotton blending will be arranged according to the spinning conditions and yarn quality.

In the process of new technology and new technology, small batch trial spinning should also be carried out to confirm the correct use of raw cotton, and to do well in trial spinning can reduce the fluctuation of yarn quality, correctly reflect the use value and economic value of fibers, predict yarn performance, and ensure that the quality of products will not fluctuate due to the span of time. Product quality can be recognized by the market.