Good raising requires that one end of the raised fluff is exposed and the other end is tightly buried in the fabric. The fibers are broken as little as possible, there is no shedding, there is a shading (the bottom cannot be exposed), and the hair head is dense, neat, fine and thick. The loss of force should be small. Therefore, you cannot expect to pull the hair once and it will be successful. You must gently pull the hair repeatedly, from the outside to the inside, and gradually deepen.
There are many factors that affect the raising effect, including equipment factors and process factors, such as the specifications of the card clothing, the grinding of the card clothing, the running status and operation of the raising machine, and fiber materials. Properties, yarn and fabric structure, fabric processing before fluffing, fluffing working conditions (temperature, humidity), etc. This article analyzes from the following aspects.
1 Card Clothing Specifications
The needle roller on the wire raising machine is a needle roller wrapped with wire needles Made of cloth. Card clothing is a long and narrow strip of cloth planted with steel needles. Steel wire stitches are planted on the base fabric in certain rows. The base fabric is made of rubber layer and cotton or linen bonded together. A good base fabric should have good elasticity, so that although the steel wire is deformed by force when fluffing, it will easily rebound and the angle of the stitches and needle insertion will remain unchanged. The base fabric should have good strength so that the card clothing can be firmly wrapped around the roller core and will not loosen even under force.
Steel needles are made of medium carbon steel and are divided into straight needles and curved needles. Its cross-sections are circular, triangular, and elliptical. Their morphological parameters include upper knee, lower knee, working angle and needle planting angle. Steel needles of different shapes and numbers make up different specifications of card clothing, which are selected according to the different types of gray cloth and raw materials when raising piles.
Generally, when raising knitted fabrics, the upper knee is required to be slightly smaller than the lower knee, and the angle between the upper and lower knees should be larger. In this way, the elasticity of the card clothing is greater, and the needle tip is easy to insert into the fabric. When raising the needle tip, it is easy to return to the original position after being raised and tilted back. The raising effect is soft, the raising is transparent and dense, there is a bottom pile, fine and thick, smooth and no floating hair. . In addition to the straight needle roller, the cleaning roller also uses straight needles, but the needle diameter is slightly thinner and the needle density is slightly thinner.
2 Grinding of card clothing
The sharpness of the card clothing and the shape of the needle tip will affect the fuzzing Speed and quality, so new card clothing and dull card clothing need to be sharpened.
The grinding of card clothing is divided into two steps: winding and grinding of card clothing. The card clothing needs to be carefully and smoothly wound onto the roller core as required. Before the new card clothing is officially wound, it is best to wind it once with right-hand and left-hand turns alternately to make the needle insertion angle correct and increase the deformation elasticity of the steel needle.
The winding of card clothing is done manually, and some also use specialized equipment. When winding, the edges of the card clothing should be close to each other in sequence, and the spiral line should maintain a certain angle with the axis core.
The winding tension should be appropriate and uniform. Excessive tension will cause the card clothing to stretch, the stitches will be weak, the needle tips will be far away from each other, and it will easily penetrate deep into the fabric when fluffing. The winding tension cannot be too small. If it is too small, it will easily cause the base fabric to bulge and fail to work properly.
The card clothing winding directions of each adjacent needle roller on the large drum are opposite to prevent the card clothing from loosening during fluffing. The outer diameter of the straight needle roller should be slightly higher than the curved needle roller (about 0.2cm), so that the former can play a carding role and support the fabric to avoid excessive penetration of the curved needle roller and damage the fabric. The outer diameter of the same type of straight roller must be strictly consistent.
The winding of the cleaning roller is also very important. The roller core must be straight and round, and the winding must be tight and flat. It must be ensured that it accurately aligns with the straight needle roller when installed on the frame ( About 0.08cm), otherwise the card clothing will be damaged or the needle tip arrangement will be disrupted, resulting in uneven cleaning and poor fluffing.
Copy grinding is the super needle and needle grinding of needle rollers, especially looper rollers. Old and dull card clothing should be ground to make it sharp and generate small hooks, which is conducive to fluffing. New card clothing also needs to be ground. In addition to its function as blunt card clothing, it can also correct the angle and pin position of the looper and smooth the roller surface.
The grinding is carried out on the grinding machine. Instead, two looper rollers are arranged parallel to each other on the bearings of the frame. The needle tips of the two rollers face each other by 0.08~0.16cm. They rotate in the opposite direction at a high speed of 1400r/min to copy needles.
The function of the needle is to grind the needle tips sideways against each other. Copying needles is divided into opposite copying and sequential copying. When the two rollers turn in the same direction as the needle tip (that is, the needle tips rotate relative to each other), it is called “counter-copying”; when they point in opposite directions (that is, the needle tips rotate in opposite directions), it is called “sequential copying.”
Generally, copy in pairs first and then in sequence. The effect on copying is more severe than that on copying. Needle copying takes about 15~20 minutes. If the time is too short, it will not work. If the time is too long, the needle tip will be too sharp or even the needle angle will change, resulting in rough fluffing and increased hair loss. The time for copying new card clothing can be longer, and the time for copying old card clothing can be longer. For needle grinding, the emery grinding stone is refueled and placed on the contact line between the two needle rollers. When the needle roller rotates at high speed, the grinding stone repeatedly moves left and right along the roller width with uniform pressure and constant speed to smooth the needle tip. Polished and small hookbacks present. The needle grinding pressure should be uniform and of appropriate size (about 1kg), and it should take 30 minutes. Whether the needle roller grinding is sharp or appropriate can be observed with a special microscope or directly touched with fingernails. The ground card clothing should give people a “sticky” feeling when touching it.
3 Influence of cotton yarn and fabric specifications
Generally, the count of pile yarn is low. To facilitate fluffing. The pile yarn can be 97.2tex (6 inches count) or 58.3tex (10 inches count). The lower the twist of the yarn, the better it is to catch the fluff, but the twist is too low, which can easily cause lint and excessive loss of strength.
The twist of cotton yarn also depends on the quality of the raw cotton used.For example, fine-staple cotton has 2.6~3.0 twists/cm (6.5~7.5 twists/inch), while coarse-staple cotton has 2.8~3.0 twists/cm (7~7.5 twists/inch). The twist must be even, otherwise the pile will be uneven. The twist direction is also related to the raising effect. The raising effect of Z twist is better than that of S twist, because the direction of the latter’s force from the raising roller is the direction in which the twist increases, so that the fiber holding force in the yarn increases.
The loop density and loop length of the pile yarn and the ratio of the amount of pile yarn and upper thread also affect the pile effect. The greater the density of the pile yarn and the larger the dosage ratio, the easier it is to produce thicker pile; conversely, the lighter the pile, the lower the warmth retention properties.
If the coil length is too short, it will be detrimental to the pile. It is not easy to produce thick pile, it is not easy to lift, and it is easy to reveal the bottom. The above factors are related to fabric design and weaving technology. Therefore, to obtain good fleece products, all processes must be coordinated in a unified manner.
4 Influence of the processes before raising
The raising of cotton knitted fabrics includes gray fabrics fleece, bleached knitted fabric fleece, dyed knitted fabric fleece (including light and dark colors), etc. Due to the different processing treatments before raising, the difficulty of raising and the raising effect are also different.
Grey fabric is easier to fluff because the raw cotton contains wax, which can provide lubrication. Bleached or light-colored knitted fabrics require strict scouring and bleaching to remove the wax on the fibers. During fluffing, the fibers are easily broken and the fabric is damaged. Knitted fabrics that have been bleached or dyed should be waxed first and then fluffed. Most dark-colored fabrics are not scouring and bleaching, which is beneficial to pile-raising. However, dark-colored fabrics use larger amounts of dyes and other chemicals, which often increase the fiber friction coefficient and require increased raising force, which is detrimental to pile-raising. Again disadvantageous.
5 Fabric temperature and humidity
Increasing the fabric temperature is beneficial to fluffing, because the cloth temperature increases , the fabric will become puffy and the oil and wax will soften, making it easy to fluff. When the temperature in the workshop is low, or when raising knitted fabrics that are not easy to fluff, they must first be heated by the drying cylinder on the fluffing machine and then fluffed, but not overheated, otherwise it will cause the fiber to become brittle, increase the amount of waste, and reduce the fluff. becomes shorter and the strength of the fabric decreases.
Dry fabrics are prone to fluffing, because the increase in humidity will increase the deformation ability of cotton fibers and increase the friction coefficient, making it difficult for fibers to be pulled out from the inside of the yarn, and the fluff will be rough. It is easy to reveal the bottom and easily blunt the steel needle. The appropriate moisture content of cotton cloth is 6% to 8%. It should be noted that the drying cylinder on the raising machine is only for heating the fabric, not for drying. If the fabric does not contain much water and the fabric is dried very dry, it will make the raising difficult. </p
