Analysis of Causes of 6-8cm Thick Yarn Defects in Spinning Machine

1. Yarn defect shape

When the top roller is in contact with the cradle, the control spring in the cradle device locks the top roller to maintain the elasticity and stability of the top roller during operation. After the upper pin spring breaks, the fiber movement in the drafting zone is unstable, causing serious uneven yarn defects, and the CVb between the tubes increases significantly. Table 2 shows the quality comparison between broken spring yarn and normal yarn on C14.6 tex.

2. Mechanism analysis

Spinning cradle is one of the key components of yarn formation, and it is also the point of application of the parallel force between the upper roller gauge and the lower roller gauge. After the upper roller circlip is broken, the position of the upper roller loses control and is affected by the vibration of the movement. The center distance moves forward or backward indefinitely, causing fluctuations in the running process and instability of fiber movement, which in turn affects the difference in yarn evenness.

3. Causes and prevention of yarn defects

Reasons for formation:

(1) Incorrect disassembly and assembly methods, twisting and tearing when disassembling the top roller;

(2) The cradle pressure is too large;

(3) The circlip is deformed and the assembly position is not correct, causing strong compression between the top roller shaft and the circlip shaft.

Prevention method:

(1) Use the correct method of disassembly and assembly, press the spring point of the circlip with your hand to relieve the pressure, and naturally take off the top roller, instead of pulling and twisting;

(2) When the spring adjusts the pressure of the cradle, use standard positioning gauges to prevent non-standard trial adjustments based on experience;

(3) Master the correct assembly method during assembly to prevent the circlip from being crushed.

Spinning machine 6～8cm thick yarn defect

1. Yarn defect shape

Spinning process 6～8 cm thick yarn defects are generally considered to be caused by roving package splicing or spun yarn splicing. However, it is found in production that they are actually caused by mechanical and suction. The shape is continuous 4 to 5 A thick yarn defect, up to 40 cm long, has strong continuity and irregularity. There is a fiber core in the yarn defect, the outer end is hairy, and the twist is small, which seriously affects the efficiency of winding production.

2. Mechanism analysis

Mechanical reasons: the sliding and abrasion of the roller transmission gear causes the keyway to become loose, leading and lagging during the transmission process, which causes the fiber assembly in the roller drafting movement to form thick yarn defects; the reason for the blowing and suction cleaner: the suction nozzle in the middle of the blowing and suction blowing directly The twisting area causes a weak ring in the twisting area. The direct air blowing affects the twisting of the yarn body, and the fiber is exposed to form a thick yarn defect.

3. Causes and prevention

Mechanical reasons:

(1) The machinery is in disrepair, and the standard of the flat car is not high and the requirements are not strict. Cause the keyway to wear;

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

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

Prevention method:

(1) Strengthen mechanical maintenance to ensure that the gear meshing quantity meets the standard;

(2) Repair the keyway and key nails in time on the flat wiping car; correctly adjust the blowing and suction position of the installation twisting area.

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