Causes And Preventive Measures Of Yarn Faults In Yarn Dyed Knitted Fabrics

With the continuous maturation of the market of colored knitted fabrics, the requirement for the quality of colored spun yarn is getting higher and higher. Therefore, it is particularly important to prevent and control various yarn defects.

The cross section (also known as cross road) is one of the most important defects in knitted fabric. It can be divided into two types: woven defect pverse and defective yarn.

According to our experience in production for many years, we will pay more attention to it.

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First, cause analysis

The problem of color spun knitted fabric caused by colored spinning is divided into two parts: one is the regular cross, the length is longer, the cloth surface is affected by several meters or even to several pieces; and the two is the short section irregular or no obvious regular local cross.

Colored spun yarn is made from the mixture of different colored fibers and natural fibers or two or more colored fibers blended according to the depth and depth of yarn.

Because of its maturity, fineness, short lint content and origin, the color of raw cotton can not be completely identical after dyeing.

There is also a certain difference in chromatic light between different vats and batches.

Therefore, different batches of raw materials spun yarn will have a certain color difference.

When using colored spun yarns in knitting mills, if there is no strict distinction between batches, a striped piece of pverse defect will appear.

Weight deviation and irregularity of 1.2 colour spinning yarn

Yarn weight deviation and irregularity are important indexes to control yarn quality. The weight deviation is too large, and the yarn number and yarn number deviated from the design number are large.

And the weight unevenness is large, which means that the internal thickness of the yarn is quite different, and the horizontal and single cross sections will also appear.

Evenness reflects the evenness of yarn thickness in a certain length.

When the yarn evenness of the entire batch is poor, the surface of the cloth is striped and uneven. When there are individual yarns in the whole batch of yarn, the evenness of the yarn is uniform and regular, which reflects that the cloth is a single cross. At the same time, when the individual yarn is coarse and thin, the cloth will appear dense or sparse cross section when the backlight is visually measured.

The twist and color of colored spun yarn are very important.

Because the twist of colored spun yarn affects the tightness of yarn structure, the twist is too small, which makes the yarn color lighter and vice versa.

When weak twisting and tight twisting appear, the cloth is a single cross.

1.5 oil and wax unevenness.

It is colored in itself. When it is stained with oil, it will cause the color of the yarn to be deep, and a single cross will be formed on the cloth.

In order to reduce the influence of hairiness on the back process and to make the hairiness neatly attached to the surface of the yarn, the color knitted yarn on the market is basically waxing. The main component of the wax block is grease, and many oils are insoluble in water.

In Wax Waxing process, if the wax block is too soft, it will cause too much grease to be attached to the yarn, so that the yarn's color will be deep, and a single cross will appear on the cloth.

1.6 wrong yarn

The characteristics of colored spun yarn are many varieties and small batches. When the yarn with similar color is mixed with different yarn numbers and different batch numbers, especially Z twist and S twist yarn, a single cross will appear.

Two, prevention and control measures

To control the difference of color and light of raw materials, each color cotton must have a relative standard sample, requiring color difference and batch difference to be no less than 4 standard sample.

The batch of color cotton with large color difference can not be mixed directly, and the amount of flower back must be strictly controlled.

2.2 uniform mixing

The color spun variety is made up of a mixture of various color fibers, which can be mixed directly in the cotton cleaning disc. It can not ensure that the raw materials are fully mixed, and the color difference between the cotton rolls is easy to cause.

Therefore, it is necessary to pre mix and mix the raw materials with different properties and colors before mixing them.

In order to ensure uniform mixing, the principle of "more loose, less beating and full mixing" is adopted to reduce the color difference between the front and rear rolls and the rolls.

At the same time, in order to ensure the uniform color of the sliver, we should adopt the principle of "horizontal paving, taking first and using first".

Different machine processes should be unified so as to reduce the difference of the color of the machine due to the difference between falling and falling.

In order to ensure the consistency of the color of the cylinder and the barrel, the strip adopts cross mixing.

2.3 accurate proofing

Before each spinning, each batch of colored spun yarn should be arranged according to the proportion of the previous batch production. Then the color contrast between the proofing and the original color spinning is made. If there is any deviation, according to the situation of the color cotton, a slight adjustment is made on the basis of the original proportion to ensure that the color difference between the actual production and the previous batch reaches 4 grade.

2.4 strictly control the quantitative deviation of each process product.

The weight unevenness of cotton coils reflects the internal unevenness, while the positive coiling rate reflects the unevenness between the rolls and the unevenness. The weight difference between the sliver and the yarn is caused by the unevenness, which directly affects the yarn density unevenness.

According to the technological requirements, the weight deviation of the raw and cooked strips is controlled well, especially the weight deviation of the cooked strips has great influence on the yarn quality, and must be strictly controlled.

Reasonable allocation of the technological parameters of each process to reduce accidental drafting; in the production process, there is no shortage of strips and roving without striping, so as to reduce long detail defects; with the uniform process of different machines, the weight difference caused by machine differences can be reduced; the weight difference between the inner and outer parts of roving will be reduced, and the roving tension can be controlled by using the thin prevention device and the control of the roving tension. The elongation of the large, medium and small yarns in the same spindle will be less than 1.5% at 1%, and the final weight of the spindle and spindle roving will be controlled at + 0.1 g/10 m.

Reduce the weight deviation and spindle deviation of different spinning machines, prevent the runaway of roving from spinning and prevent the yarn slid and pressure failure.

2.5 strictly control the evenness of each process product.

From one aspect, the evenness of the evenness can reflect the management level of an enterprise.

The mechanical performance and state, production management level, quality consciousness of the truck operators and operation technology level of each machine platform have great influence on the quality of WIP.

Therefore, only by strengthening process management, operation management and equipment management of online production can we ensure evenness and stable quality of yarn evenness.

Tight twist yarn and weak twist yarn are produced in the spinning process.

On the one hand, we need to strengthen the training and assessment of operators' operational skills; on the other hand, we should strengthen the periodic inspection of the mechanical states of the twisting parts, so as to eliminate the slipping of the spindle belt, the uneven tension of the spindle belts, and the breakage of the spindle belts.

It is important to ensure the stable twisting efficiency in the pipe.

2.7 oil pollution, waxing bad control.

All processes should be strictly observed in the maintenance of equipment such as wiping and refueling, so as to prevent oil spills during operation and to clean the passageways and reduce contact opportunities between yarn and oil.

Wax waxes should be used in different seasons and wax with high water solubility.

Strengthen the maintenance and inspection of the waxing device, make the waxing device in normal state, touch the wax block too soft, and deal with it in time, so as to prevent the yarn body from being embedded in the wax block.

2.8 wrong yarn control

It is necessary to strengthen the management of containers (spinning tube, paper tube head) and packing labels of on-line products, and strictly distinguish the containers with similar color.

The arrangement should be reasonable, the area should be divided before packing, and the packaging process should be standardized.

The two color light is close to each other, and its line density deviation is only about 10%, or the deviation of the line density of the same species is large.

Therefore, we must strictly control the offset channels, prevent long and coarse yarn defects from leakage, and require the winding process to set alarm for such a situation.

It is a common phenomenon to cause yarn defects on the cross section of knitted fabrics.

Yarn defects, identify causes and timely prevention is particularly important.

It is necessary to adopt reasonable cotton blending technology, ensure the full mixing of raw materials, and arrange the proofing before each spinning, ensure that the difference between the color and the first batch is up to the standard requirement; strictly control the weight deviation and evenness of each process product; pay attention to equipment maintenance and operation specifications to reduce the oil yarn; strengthen the maintenance, maintenance and maintenance of important parts, and reduce the prevention and control of such yarn defects such as tight twist yarn and weak twist yarn.

The quality management and production management level of the enterprise has been raised comprehensively, and the yarn that meets the quality requirement is finally produced, which effectively reduces the defect of the cross section of the knitted fabric.