As one of the carding elements of the combing machine, the cylinder is responsible for combing the front end of the fiber clumps, eliminating the front hooks of the fibers, improving the straightening and parallelism of the fibers, and taking away the short lint, neps and impurities in the fiber clumps ( This includes the short lint, neps and impurities trapped during the top combing process of combing the ends of the fiber clusters). It can be seen that the cylinder plays a decisive role in the entire carding process of the combing machine, and its condition, especially the intarsia problem, must be paid great attention to. Based on many years of experience in combing machines, netizens had a heated discussion about this,
Let us hear what are the causes of cylinder inlays, and what good suggestions for improvement netizens have.
cause
The first row of needles in the cylinder is broken or tilted. Accidental damage to the cylinder seriously destroys the sharpness of the cylinder’s tooth tips, making it difficult to remove the fibers and causing cylinder mosaic and congestion. For example, due to lack of oil in the front swing arm needle roller bearing and wear of the cylinder shaft, the nipper plate sinks, causing the clamp lip of the nipper plate to collide with the cylinder comb needle, causing damage to the needle teeth. Combing the fibrous beard clumps with the combing cylinder is a holding combing, that is, the upper and lower nippers hold the rear end of the fibrous beard clumps, and each row of needles of the cylinder pierce the fibrous beard clumps from the gripping part of the nipper lips in sequence, and proceed from back to front. Carding is divided, so the first row of needles experiences the greatest fiber resistance and is prone to wear and fatigue fracture first. When the tooth density of the front area of the used cylinder is too large, or the working angle of the front area needle teeth is too small, the needle teeth gripping ability is too strong, or the front area needle teeth are not partially quenched, and the tooth tip hardness is not enough, the first row will be accelerated. Fatigue fracture of needle teeth. When the small roll is too heavy in weight, the transverse uniformity is not good, or the fiber straightness in the small roll is poor, the wear and fatigue fracture of the first row of needles will also be accelerated. Foreign objects in the fiber whiskers will first damage the first row of cylinder needles, and may cause broken or crooked needles.
The density transition of the rack is unreasonable. Each rack of the embedded sawtooth cylinder has the same size and can be replaced with each other and freely combined, so the total carding points of the embedded sawtooth cylinder can be more or less. Embedded cylinders are more spinnable than bonded cylinders and are widely used by textile companies. However, the combination of racks with different densities is not arbitrary, and the matching needs to be careful. If the tooth density transition is unreasonable, it can easily lead to the first row of pins of an over-density rack becoming inlaid due to fibers filling the bottom of the teeth. For example, when spinning low-nep yarn, the rack density of a certain 90° embedded cylinder is designed to be 43T/cm2, 43T/cm2, 84T/cm2, 228T/cm2, and 266T/cm2. The total carding points are as high as 41,000. . Due to the huge difference in tooth density between the third rack and the fourth rack, soon after the combing machine was running, it was found that the first row of needles on the fourth rack was inlaid. If the fourth rack was changed to a density of 199T/ cm2 rack, the fourth rack inlay problem no longer exists.
Brush status. If the brush is in poor condition, it will not be able to effectively clean the cylinder, causing the cylinder to become embedded and stuffed, affecting the carding effect and causing damage to the cylinder comb needles. After the brush has been running for a period of time, especially after the brush has been running for 18,000 hours, the brown hairs of the brush begin to fall off. The tips of the brown hairs are sparse and uneven. Dirty cotton impurities form hard lumps and are deposited in the brush. The diameter of the brush gradually decreases. Small, its surface linear speed is reduced, and the above factors greatly reduce the working efficiency of the brush.
Sugar content of raw cotton. When processing raw cotton with high sugar content, the sugar in the raw cotton will liquefy and precipitate due to heat and moisture absorption, increasing the adhesion of the raw material. This is not conducive to the opening and carding of raw cotton, nor is it conducive to the removal of impurities, resulting in a large amount of adhesive large impurities entering the combed rolls. When the combing machine combs the small rolls, large adhesive impurities will get stuck in the tooth gaps in the front area of the cylinder, forming mosaics. A typical example of cylinder inlays caused by high sugar content in raw materials is American PIMA cotton. During production, we found that whether it is bonded Graf cylinder or embedded Schier cylinder, as long as it is spun with high sugar content With PIMA cotton, cylinder inlays will appear very quickly. When processing raw cotton with low sugar content, there will be no intarsia in Graf cylinder or Schier cylinder.
Elimination method
Cylinder front area rack is preferred. In order to avoid breakage and inversion of the first row of cylinder needles, the tooth tip hardness should be high (HV800 or above), the working angle of the needle teeth should not be too small (about 60°), and the tooth density should not be too large (25T/cm2~45T/ cm2) as the front rack of the cylinder.
When combining cylinder racks, the tooth density transitions reasonably. The combing of the front end of the fiber beard by the cylinder is a progressive combing, and its intensity is from strong to weak, so the density of the cylinder teeth should be arranged from thin to dense, with a reasonable transition. Otherwise, it is easy to cause cylinder inlay and aggravate fiber damage.
Choose a brush with good performance and check the condition of the brush regularly. At present, there are many good and bad brushes on the market. You must choose a brush with good elasticity, small fineness and stiffness. Regularly check the diameter of the brush, adjust or replace the speed in a timely manner to ensure the linear speed ratio between the brush and the cylinder; regularly check the depth of the brush penetrating into the cylinder to ensure the smoothness of the cylinder. Taking the FA261 combing machine as an example, after the brush has been running for 1500 hours (about 2 months), use the distance block to check and adjust the position of the brush shaft, and at the same time loosen the two nuts screwed on the brush sleeve. Remove the brush and turn it around. After switching, use a wrench to tighten the nut on the brush sleeve. After the test run, tighten it again 1 to 2 times. For dirty cotton stuck in the brush and forming a hard lump, a flat plate made of elastic card clothing can be used. Brush to clear. When the brush diameter is used to 95mm, the brush diameter should be appropriately increased.At high speed, brushes with sparse brown hair, severe hair shedding and brushes with a diameter less than 85mm must be scrapped.
Optimize the ration of the small rolls, improve the transverse uniformity of the small rolls, and increase the straightening and parallelism of the fibers in the small rolls to reduce the fiber resistance on the first row of needle teeth and delay their decline.
When processing raw cotton with high sugar content, the opening and carding intensity of the cotton blower and carding machine should be strengthened to separate impurities and fibers as much as possible; the negative pressure of vacuuming should be increased and the air flow should be fully utilized to separate and absorb For impurities, large impurities should fall off early and be less broken, and small impurities should be fully discharged to reduce the impurity content in the raw strips.
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