How to prevent conventional polyester yarn defects caused by equipment factors

Spinning machine 6 ～ 8cm slub conventional polyester yarn defect

 

a.Conventional polyester yarn defect shape

Spinning process 6 ～ 8 cm slub conventional polyester yarn defect is generally considered to be a yarn defect caused by the roving package joint or spun yarn joint, but it is found in production that it is actually a yarn defect caused by machinery and blowing air, and its shape is continuous 4 ～ 5 A slubby yarn defect, up to 40 cm long, with strong continuity and irregularity, with a fiber core in the yarn defect, hairy outer ends, and low twist, which seriously affects the production efficiency of the winding.

 

b.Mechanism analysis

Mechanical cause: The roller drive gear wears and loosens the keyway, leading to a lag in the transmission process, which causes the fiber aggregation in the roller drafting motion to form a stubby conventional polyester yarn defect; blowing and suction cleaner Reason: blowing the suction nozzle in the middle The twisting area causes a weak loop in the twisting area. The direct airflow affects the twisting of the yarn body, and the fibers are exposed outside the body to form thick yarn defects.

 

c.Causes and prevention

Mechanical reasons:

(1) The machine is in disrepair, and the standard of flat wipe is not high, and the requirements are not strict. Causing keyway wear;

(2) The bearing is damaged and the gear mesh is too large, causing abnormal wear;

(3) The adjustment position of the suction cleaner is not correct, and it is not adjusted according to the regulations.

 

d.Prevention methods:

(1) Strengthen mechanical maintenance to ensure that the meshing amount of gears meets the standards;

(2) Timely repair the key groove and key nails on the flat car; adjust the blowing and suction position of the twisting area correctly.

2. Hairpin yarn defects caused by hanging travellers

 

a.Yarn defect shape

Hairiness is one of the important yarn defects that affect the quality assessment, and is generally produced in the drafting and twisting triangle. In actual production, the hairiness caused by the hanging of the traveler not only affects the quality, but also is not easy to find during the inspection. Specific form: Hairy hair is concentrated and dense, hairy appearance, the binding layer of the winding layer in the bobbin is unclear, and the hairiness index of l-9 mm is increased to different degrees

 

b.Analysis of yarn defect formation mechanism

The speed of the traveller is proportional to the speed of the front roller. When the traveller hangs flowers or the cleaner accumulates, the friction of the ring and traveller increases, and the airflow pattern formed by the movement changes, resulting in the pulling movement between the fibers Form hairiness. At the same time, the increase in the temperature of the traveler and the steel ring, the flower restraint traveler is not easy to dissipate heat, and the viscosity of the air is large, which affects the polymerization of the fiber. After the traveler is hung again, the speed is unstable and the tension from the spinning section to the winding section is affected , Increase the diffusion of edge fibers. Easy to cause hairiness.

 

 c.Causes and prevention of yarn defects

Reasons for formation:

(1) The traveller has astringent hair and poor quality;

(2) The surface of the ring is rough, which increases the wear of the traveler and forms hairiness;

(3) The distance between the traveller and the cleaner is too large or does not work, causing the cleaner to function poorly and form hairiness;

(4) The relative humidity in the workshop is too low and there are too many flying flowers. It is easy to attach to the traveller with the traveler movement, forming a traveller hanging flower.

 

d.Prevention methods:

(1) Different yarn variety adopts different traveller gauges. Practice has proved that the yarn below 14.6 tex adopts the distance between the traveller and the cleaner to be 1.45 mm, 18.2 to 22.4 tex to 1.6 mm, and 27.85 tex to 1.7 mm, which can be effectively prevented. The hairiness yarn defect caused by the traveler hanging flower requires that the traveler cleaner function well. The wire ring without cleaner will be hung again after cleaning for 2 h;

(2) Strengthen the operation management, clear the hanging flowers every doffing;

(3) Control the flying flowers and relative humidity in the workshop.

 

Breaking of the draft drive shaft after spinning causes fineness variation

 

a.Yarn defect shape

The transmission shaft of the middle and rear rollers of the FA series spinning machine is long, and the transmission load is too large, which is easy to break, and it is not easy to find after the break. The yarn is severely deviated during the detection, and the serious one can be determined as degraded. In actual production, when producing 14.6 tex yarn, the variation is 17 tex, 18.2 tex variation is 19.5 tex, 22.4 tex variation is 24.6 tex, etc., flowing into the subsequent process will cause a large area of ​​cloth Problems such as horizontal movement and uneven dyeing.

 

b.Analysis of yarn defect formation mechanism

The rear roller drive is responsible for the buffering and decomposition of the spinning draft distribution. The rear roller drafting is an important supporting point for improving the drafting capacity of the front zone. The main function of the rear zone drafting is to prepare for the front zone, so that the sliver feeding the front zone has a uniform structure of tightness, and at the same time ensure the distribution of the friction zone in the front zone to form a stable draft zone in order to give full play to the apron control The function of fiber movement achieves the purpose of reducing thick spots and improving the appearance quality of cloth. When the rear zone roller loses the active control of the original draft multiple, it becomes the inertial force pulled by the collective feeding of the sliver, and the draft multiple is reduced at this time. The total draft is the product of each draft multiple. The change of the post draft causes the change of the total draft. The decrease of the post draft causes the decrease of the total draft and the quantitative increase of the yarn.

 

c.Causes and prevention of yarn defects

the reason:

(1) After the rear roller breaks, the front roller drives normally, and the rear roller continues to drive through the roving sliver, but the draft multiples are no longer controlled, resulting in variations in yarn fineness;

(2) The equipment is out of repair, the overhaul period is too long, the drive shaft is not replaced in time, and it runs fatigued;

(3) The position of the front wall panel is skewed;

(4) The test period is too long.

 

d.Precaution:

(1) When installing the equipment, the front and back spacing of the front wall panel and the pagoda seat must be strictly corrected. The longitudinal requirement is 11 ± 0.50 mm, and the horizontal direction is corrected with a special tool. The 0.10 mm micrometer is extracted as the standard; Must be controlled within a tolerance of 0.30 mm;

(2) Regardless of the size of the variety, ensure the quantitative deviation of the daily test;

(3) Strictly determine the supply of Taiwan to prevent expanding the tracking range and reducing losses after problems occur;

(4) Replace the drive shaft within 5 to 6 years to prevent fatigue operation;

(5) Color-code the back roller and check it regularly.

The main reason for yarn defects caused by spinning equipment factors is that the overhaul and maintenance are not timely. A strict maintenance system should be adopted to prevent yarn defects caused by equipment factors. The maintenance standards are based on the implementation of the process requirements of various departments. By taking measures, the yarn defects caused by equipment factors can be reduced within a certain range, and the quality of products can be continuously improved.

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