Technology | Analysis and Control of Yarn Caused by Spinning Equipment Factors
1 The types and characteristics of yarn defects caused by spinning process equipment factors The yarn defects produced in the spun yarn process are usually two types of yarn defects, sporadic and sporadic. Permanent gauze is generally dry CV, kilometer-thick, kilometer-detailed and kilogram-needled; sporadic gauze is mainly 100,000 meters of harmful gauze, with emphasis on long thick and long details, as well as being able to clear Qualitative yarn defect. The yarn defects caused by equipment factors are in between the two. They are often characterized by sporadic incidents. They are mainly yarn defects caused by mechanical operations. They are common and sudden, and they are difficult to detect and control. Harmful, affecting yield and quality. The specific types are: no aprons, spinning, uneven mechanical waves, thick sections, misfiring caused by mechanical variation, hairy yarn defects, etc. 2 Causes and analysis of common yarn defects in spun yarn 2.1 Without apron spinning yarn 2.1.2 Mechanism Analysis 2.1.3 Causes and Prevention (1) The lower apron pin is inflexible and misaligned, causing the apron to run off or fall off; (2) The inner wall structure layer and support layer of the apron are abraded, resulting in fracture deformation and damage to the apron; (3) The temperature and humidity are too large. The apron is tangled, hung, and wound so that the apron is damaged and fractured. Aprons. Prevention methods: (1) Strengthen overhaul, regularly check the quality of the leather collar, and find that it is not replaced in time; (2) Strengthen basic management to ensure the temperature and humidity during operation, and reduce the phenomenon of entanglement, hanging, and winding; (3) Strengthen the responsibility education for the operator and find that the damage is promptly replaced. 2.2.3 Causes and Prevention of Yarn Breaks (1) Incorrect dismantling method, twisting and tearing when disassembling the top roller; (2) The cradle pressure is too large; (3) The spring is deformed and the assembly position is not correct, so that the upper roller shaft and the circlip shaft are strongly compressed. Prevention methods: (1) Using the correct method of dismantling and dismantling by hand, pressurize the elasticity point of the spring to remove the pressure, and naturally remove the upper roller, instead of using a stiff pull twisting method; (2) When the spring adjusts the cradle pressure, it is adjusted by the standard positioning gauge to prevent the non-standard trial adjustment by experience; (3) Master the correct assembly method during assembly and prevent the spring from being damaged. 2.3 Spinning Machine 6~8cm thick yarn 2.3.2 Mechanism Analysis 2.3.3 Causes and Prevention (1) The machinery is in disrepair, the standard of the flat car is not high, and the requirements are not strict. Resulting in keyway wear; (2) bearing damage, excessive gear mesh, causing abnormal wear; (3) The suction cleaner does not adjust the position, and does not adjust according to the regulations when changing. Prevention methods: (1) Strengthen mechanical overhaul to ensure that the amount of gear mesh meets the standard; (2) The flat car shall timely repair the key slot and the key screw; correctly adjust the blowing and suction position of the installation twist zone. 2.4 Wire loops cause hairy yarn defects 2.4.3 Causes and Prevention of Yarn Breaks (1) The wire ring has astringent hair and the quality is not good; (2) The surface of the ring is rough, which increases the wear of the traveler and forms hairiness. (3) The distance between the traveler and the cleaner is too large or does not work, causing the cleaner to malfunction and form hairiness; (4) The relative humidity in the workshop is too low and too much fly. It is easy to attach to the traveler with the traveler to form the traveler. Prevention methods: (1) Different wire types use different wire cleaner distances. It has been proved that yarns under 14.6 tex have a distance of 1.45 mm between the traveler and the cleaner, 1.6 mm at 18.2 to 22.4 tex, and 1.7 mm at 27.85 tex, which can be effectively prevented. The hairy yarn yam caused by the wire looper hangs at the same time, and the function of the wire loop cleaner must be good. Cleaner-free wire rings will be re-hanged after 2 h. (2) Strengthen the operation and operation management, clean up the hanging flower once every doffing; (3) Control plant fly and relative humidity. 2.5 Fineness variation due to breakage of draft shaft after drafting 2.5.2 Analysis of Yarn Formation Mechanism 2.5.3 Causes and Prevention of Yarn Breaks (1) After the rear roller breaks, the front roller is normally driven, and the roller is driven by the roving sliver to continue the transmission, but the draft multiple is not controlled, resulting in variation in yarn fineness; (2) The equipment is in disrepair, the overhaul period is too long, the drive shaft is not replaced in time, and fatigue is running; (3) The position of the front wall panel is skewed; (4) The test period is too long. Precaution: (1) When flat equipment is installed, the vertical and horizontal gauges of the front wall panel and the pagoda tower must be strictly calibrated, and the longitudinal requirement is 11±0.50 mm. The horizontal tool is calibrated with a special tool, and the 0.10 mm micrometer specimen is used as the standard; the wall panel centerline Must be controlled within a tolerance of 0.30 mm; Printed Fabric Online,Cotton Printed Fabric,3D Printed Fabric,Digitally Printed Fabric Shaoxing City Laiteng Imp.&Exp Co.,Ltd , https://www.laiteng-tex.com
2.1.1 Comparison of patterns
Without under-apron spinning is caused by out-of-control equipment overhaul and operation management in the production process, which produces a regular 7-8 cm mechanical wave, which has a great influence on the fabric surface and is not easy to find in actual production. Specific quality indicators are shown in Table 1. (CJ28.5 tex varieties).
In the drafting movement of the fine yarn, the upper and lower aprons constitute a flexible jaw, which holds the fibers in an orderly speed, and shifts the focus toward the jaws. When there is no bottom apron spinning, only the top apron controls the fiber, the slip rate of the nitrile rubber and the steel roller increases, and the ability of the middle bottom lozenge diamond to hold the fiber is reduced and fluctuates, so that the yarn is affected by the output. The influence of mechanical periodic motion produces regularity and unevenness.
No reason why the lower apron is spinning:
2.2 The upper pin snap spring breaks to cause mechanical wave
2.2.1 Yarn Shape
When the upper roller is in contact with the cradle, the control spring in the cradle device plays a role in locking the upper roller and maintains the elasticity and stability of the upper roller during operation. After the upper pin spring was broken, the fiber movement in the draft zone was unstable, causing serious uneven yarn defects, and the CVb between the pipes increased significantly. Table 2 shows the comparison of the quality of the broken spring yarn and normal yarn on C14.6 tex.
2.2.2 Mechanism Analysis
The fine yarn cradle is one of the key components of the yarn, and it is also the force point of the parallel force between the top roller gauge and the bottom roller gauge. After the top roller roller spring breaks, the top roller position loses control and is affected by the movement vibration. The undetermined forward or backward movement of the center distance causes fluctuations in the running process and instability of the fiber movement, which in turn affects the difference in the resulting yarn.
Cause:
2.3.1 Yarn Shape
Spinning process 6-8 cm coarse yarn yam is generally considered to be yarn defect caused by roving package joints or spun yarn joints. However, it is found in the production that the yarn stencil caused by the mechanical and blowing suction is actually in the form of continuous 4-5 Slub yarns, up to 40 cm in length, have strong continuity and no regularity. There are fiber nuclei inside the yarns, hairs on the outer ends, and small twists, which seriously affect the winding efficiency.
Mechanical reasons: The swaying of the roller drive gear causes the keyway to be loosened, leading to hysteresis in the driving process, which causes the fiber assembly in the drafting movement of the roller to form a thick yarn defect. The reason for the blowing and suction cleaner is that the suction suction blows in the central suction nozzle. The twisting zone caused a weak ring in the twisting zone. The air blown directly affected the twisting of the yarn body, and the fibers were exposed to form a thick knot yarn.
Mechanical reasons:
2.4.1 Yarn Form
Hairiness is one of the important yarn defects affecting the quality assessment. It is usually produced in the drafting and twisting triangle area. In actual production, the hairiness caused by the wire looper not only affects the quality, but also cannot be detected when testing. The specific shape: hairiness is concentrated and the appearance is hairy. The bound layer of the winding layer in the bobbin is unclear. The hairiness index of l-9 mm is increased to varying degrees. The comparison between the normal hairiness index and the hairiness index of the looper is shown in Table 3. .
2.4.2 Analysis of Yarn Formation Mechanism
The speed of the traveler is proportional to the speed of the front roller. After the traveler or the cleaner deposits, the friction between the ring and the traveler increases, and the air flow formed by the movement changes, causing a pulling movement between the fibers. Form hairiness. At the same time, the temperature rise of the wire ring and ring increases, and the bounding of the flower coat is not easy to dissipate, and the viscosity of the air is large, which affects the polymerization of the fiber; the speed of the wire ring is unstable after being hung up again, and the tension from the spinning section to the winding section is affected. , increased the proliferation of edge fibers. May cause hairiness.
Cause:
2.5.1 Yarn Shape
The drive shaft length of the mid- and rear-back roller of the FA series spinning frame is too large for the transmission load, and it is prone to breakage. It is not easy to find after breaking. The yarn is severely displaced during testing and can be determined to be severe. In actual production, when producing 14.6 tex yarns, it is changed to 17 tex, 18.2 tex is mutated to 19.5 tex, 22.4 tex is mutated to 24.6 tex, and so on. After inflow, it will cause a large area of ​​cloth. From horizontal, uneven dyeing and other issues.
The rear roller drive bears the cushioning effect of the distribution of the spinning draft. Rear roller drafting is an important support point for improving the drafting ability of the front zone. The main role of the rear zone drafting is to prepare the front zone so that the sliver in the front zone is evenly packed, and at the same time, the distribution of frictional boundaries in the front zone is ensured to form a stable draft zone so that the apron control can be fully utilized. The role of fiber movement, to reduce the rough and improve the appearance of the quality of the cloth. When the rear zone roller loses its original draft multiple and actively controls, it becomes pulled by the inertia force generated by the collective feeding of the sliver, and the draft multiple at this time is reduced. The total draft is the product of the draft multiples. The change in the draft multiple causes a change in the total draft. The decrease in the draft multiple causes a reduction in the total draft and a quantitative increase in the yarn.
the reason: