Carding technology is one of the key technologies in the cotton production process, fiber carding quality directly affects the removal of impurities, drafting and other processes to achieve results. Cotton knots are cotton fibers tightly wound together in the fiber knot, there is a part of the cotton knot contains non-fiber material, such as seed, leaf, stem and other impurities. The high content of cotton knots will directly affect the quality of the yarn at a later stage. How to effectively reduce the knot through the carding process? The following four points deserve your attention.
Stable and smooth airflow
Stable airflow is a prerequisite for reducing tufts.
Knot from its formation, can be divided into three categories. The first category is caused by raw materials, the second category is caused by the primary processing of raw cotton ginning, the third category is caused by the production process. In the carding machine before these three types of knots already exist, therefore, in the carding process to reduce the cotton knot task is more onerous. Fiber, cotton knot in the cover - Sillim carding area with the airflow attached to the surface layer running, under the action of centrifugal force from the Sillim needle teeth grip, be thrown to the cover tendency. Due to the large mass of the cotton knot, relative to the length of the single fiber is short, so it is easier to get out of the tin holding. The single fiber is lighter in mass and longer in length, so it is easier to be gripped by the needle. At the same time, due to the longer fibers being thrown to the cover, the spacing between the carding area of the sillim-cover is smaller, and therefore it is easy to be gripped again by the sillim needle teeth, while the probability of the cotton knot being gripped again is smaller. Through the effective cooperation between the sillim and the cover plate, the purpose of reducing the cotton knots is finally achieved. In this process, the fibers and knots of carding, transfer, separation, etc. are inseparable from the role of airflow, so the stable airflow is a prerequisite for the effective reduction of cotton knot.
The principle of card airflow control
The principle of card airflow control is: reasonable discharge of cotton, uniform and stable airflow control, to prevent the key parts (especially a few triangular area) with the thickness of the surface layer, make up for the flow direction of the airflow on the fiber movement and the structure of the cotton network has an impact.
Methods and means of controlling airflow mainly lies in the control of the amount of airflow generated. The surface layer generated by the high-speed rotation of the seline is the main cause of airflow, followed by the felting roller. Therefore, a reasonable speed of seline and prickle roller is crucial to stabilize the airflow. Reasonable distribution of airflow at various points (especially the triangle) methods are: the use of cover boards, leakage of the bottom of the process at the spacing, reasonable distribution of airflow; the use of low-pressure cover, web cleaner, dust removal and miscellaneous at the negative pressure suction mouth to guide and relieve the release of high-pressure area of the airflow; a reasonable airflow replenishment helps to stabilize the falling cotton, holding the cotton web. Card process spacing at various places should be considered as a whole, such as large leakage bottom exit spacing changes, it will directly affect the prick roller - Silliman triangle at the airflow and pressure, moving a point, may involve more than one change, so it must be a comprehensive consideration of these factors, and most importantly, according to the actual state of the equipment to optimize.
Maintain good mechanical condition
Tight spacing, strong combing is an important means to reduce the cotton knot
For the enterprise, reduce cotton knot is a simple and complex work. If the mechanical condition is poor, such as machine vibration, poor balance, tin, dowel and roller eccentricity, etc., will produce in the carding process of rubbing fibers, the formation of a large number of knots. Therefore, under the premise of ensuring airflow control, good mechanical control is also required. In the case of mechanical state allows, tight spacing, strong combing is an important means of carding to reduce the cotton knot. The spacing between the roller and the sillicon is too large, the sawtooth is not polished, easy to cause the sillicon - sillicon roller stripping between the bad, the sillicon roller back to the flower and make the cotton knot increased significantly; sillicon and the dorf spacing is too large, so that the sillicon around the flower, the cotton knot increased.
Focus on equipment configuration, improve combing degree, reasonable distribution of the efficiency of weed removal
When the silliman, cover and dorf needle teeth are blunt or burr, the fiber can not be repeatedly transferred between the two needle surface, easy to float between the two needle surfaces, by other fibers rubbing the formation of more knots, so should pay attention to the configuration of the equipment to improve the degree of combing to reduce rubbing fibers. In addition, the reasonable distribution of impurity efficiency, so that the poor adhesion rate and large impurities discharged by the roller parts, strong adhesion rate of small impurities discharged by the cover can also reduce the effect of cotton knot. Needle teeth on the fiber should have a good ability to penetrate into the cotton knot. Because only the needle teeth deep into the knot inside, it is possible in the carding force under the action of the cotton knot fully loosened. If the needle teeth are blunt, can not effectively puncture the cotton knot, just contact the surface of the cotton knot, the cotton knot rubbing will be more and more tight, at the same time, the needle teeth can not effectively hold the fibers, so that the original has been separated from the fibers through the rubbing into a new cotton knot.
Rational division of labor in each area
Carding machine parts in addition to a reasonable division of labor. Generally larger and easy to separate the impurities should be implemented early fall less broken principle, and the adhesion of impurities, especially with long fiber impurities, in it and fiber separation is not early fall, should be fully combed in the card to be removed. In addition, when the original cotton maturity is poor, with more fiber impurities, should be an appropriate increase in the card falling cotton and in addition to the burden.
Card sash roll part is the focus of the miscellaneous area, should make the broken seeds, stiff pieces and impurities with short fibers in the area of the discharge, so as to avoid impurities are broken or embedded tin Lin needle teeth and affect the combing effect. Therefore, in addition to a small amount of adhesive impurities, the roller part should fall early and fall more. Reasonable configuration of the roller speed and after the car process, to improve the roller part of the removal of impurities in addition to the efficiency, reduce the cotton knot has an obvious effect.
The specification of the needle cloth of silliman and cover plate and the spacing between the two needle surfaces, the position of the upper mouth of the front upper cover plate, the spacing between the front upper cover plate and silliman, and the speed of the cover plate, etc., all affect the number of cotton knot impurities in the sliver. Therefore, for poor maturity, containing harmful defects more raw cotton, should pay attention to the role of the cover plate work area to exclude knotted impurities.
Reasonable control of openness and temperature and humidity
Reasonable control of opening degree
Before the fiber into the card should have a good degree of openness. Through the knot research data analysis, confirmed that the knot type is different, the size is not the same. In general, only by the fiber material composed of knots contain at least 5 or more than 5 fibers, the average is close to 16 or more than 16. Therefore, before the fiber into the card should have a good degree of openness, in order to make the cotton knot more exposed, so that more contact with the needle teeth to the cotton knot, to lay the foundation for combing open cotton knot.
Reasonable control of temperature and humidity
Temperature and humidity on the cotton knot impurities also have a greater impact, to strengthen control, reasonable adjustment. Raw cotton and cotton roll moisture back rate is low, the impurity is easy to fall, cotton knot and bunch of silk is also more likely to reduce. Carding workshop should control the lower relative humidity, increase the rigidity and elasticity of the fiber, reduce the friction between the fiber and the needle teeth and tooth gap between the congestion, in order to reduce the cotton knot. However, when the relative humidity is too low, it is easy to produce static electricity, the cotton net is easy to break or break, but also reduce the raw bar back to the moisture rate, the latter process of drafting is unfavorable.