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  • Zhejiang Wanshifa Textile Machinery CO.,Ltd

Air Jet Loom Weaving Defects Causes And Solutions

Time:19 January 2017 Click:1096
Air jet loom weaving defects
(1)Electromagnetic needle time, the main nozzle spray yarn time and opening time do not match.
(2)The selvedge yarn on the left side or other side is loose.
(3)The main nozzle is installed incorrectly.

Elimination methods
(1) Delay the time of weft yarn left the electromagnetic needle  and advance opening time.
(2) Correct the twist yarn and the false side yarn tension, or correct the opening time.
(3) Use the main nozzle to adjust correctly.

Broken weft caused by twist of weft and warp.
Weft yarn and the warp yarn on the middle twist into S-shape. The warp yarn tension is uneven or warp yarn has defects will lead to the opening failure, so that the loom may stop or create double weft defects.

(1)Warp tension is too small or yarn tension is uneven.
(2)Warp yarn defects (feathers, knots, neps, cotton balls, fly attachment, etc.).
(3)The opening is too small.

(4) Left scissors cut yarn badly.

Elimination methods
(1)Measure and increase the warp tension, eliminate the tension unevenness and other factors.
(2)Remove yarn defects and tail yarn is not more than 3mm.
(3)Increase the opening height appropriately.
(4)Adjust the left scissors work time and blade content to sharp the scissors.

Air jet weaving looms--Uneven length of weft insertion
The length of the weft introduced to cloth-fell is different. Such situation mainly caused by the instability of weft storage and the insufficient weft insertion force.
(1)Weft preload is insufficient.
(2) The closing time of the electromagnetic needle is too early.
(3) The main nozzle is blocked by cotton yarn and the pressure is too low.
(4) Weft yarn winding shape is not good or winding hardness is not appropriate. Weft yarn quality is poor with yarn defects, joints, flying cotton velvet and other attachment.

Elimination methods

(1) Remove the fly and check the jet airflow.
(2) Re-correct winding.
(3) Adjust the pressure according to the specified methods and standards.
(4) Increase the weft pre-winding volume appropriately.
(5) Delay the closing time of the electromagnetic needle.
(6) Increase the main nozzle pressure.
(7) Remove the clogged lint of the parts.
(8) Replace the form of weft winding to improve the weft cylinder hardness, and improve the quality of weft yarn vigorously to reduce yarn defects.

Air jet Loom --Weft Tip Break Type
The jet pressure of weft is too high or it is caused by weft weak section.
(1) The main nozzle pressure is too large.
(2) The power of shear and blow is too strong.
(3) Weft yarn is uneven with many little sections.
Elimination methods
(1) Reduce the main nozzle pressure.
(2) Reduce the shear blowing pressure.
(3) Replace weft yarn and take measures to improve the quality of weft.

Air jet loom --weft yarn interrupted break type
The weft insertion force is too strong, the action time is too long or the weft strips is blown off in the width of the cloth so that the loom may stop or form double-thin defects.
(1) Weft release angle is too small.
(2) The main and auxiliary nozzle pressure is too high, opening (start and end time) is too large, auxiliary nozzle injection angle is too large.
(3) Weft yarn has weak yarn.

Elimination method

(1) Increase the release angle appropriately.
(2) Reduce the main and auxiliary nozzle pressure, check the weft flight curve, reduce the opening (start and end time), avoid excessive jet, and reduce the auxiliary nozzle injection angle.
(3) Exchange weft to improve the quality of weft.

Air jet Loom--weft yarn break at weft storage side
The weft insertion force is too strong or weft yarn has weak yarn in the weft release stop process.
Shearing fault broken type: The reason of shearing fault broken is that the weft on main nozzle side is not cut during the time of wefting and beating-up.
(1)Scissors blade are not sharp with poor meshing.
(2) Scissors installation location is not good, the shear time is not standard.
(3) Shear blowing pressure is too low.

(4) The weft reaches the opposite side later.

Elimination methods
(1) Grinding the blade by cycle, and adjust the meshing well.
(2) Correct the position and adjust the time according to the scissor installation specifications.
(3) Reduce the cut blowing pressure appropriately.
(4) Increase the pressure of the main and auxiliary nozzles and extend the time of auxiliary jet nozzle.

Air jet loom--stop by error
Weft yarn reaches normally, but the machine can’t get right signal because of the abnormal weft flight, twisted edge yarn, warp side yarn, electrical failure and other reasons, resulting in downtime.
(1) Weft yarn is not normal.
(2) The twisted yarn on the right side is loose.
(3) The shape or position of the weft reaches the probe is not correct.
(4) The cable of probe head has problem, or the probe's steel reflex surface is not clean.
(5) Poor sensitivity of the probe head, detection board is troublesome.
(6) The gap between probe head and reed is not appropriate.

(7) The dents of shaped reed vibrate.

Elimination methods
(1) Adjust the nozzle position, clear lint and solve the problem of weft relaxation.
(2) Adjust the side yarn tension, so that the edge yarn reed can meet the specifications.
(3) Adjust the angle of the last set of auxiliary nozzles and keep a distance of about 50mm from the weft head WWF1.
(4) Replace the defective weft in time, and often keep the probe head and reed cleaning.
(5) Check the sensitivity of the weft yarn detector, so that it is not empty. At the same time check and replace the weft plate.
(6) Adjust the gap between the weft head and the reed according to the installation specifications.

(7) Adhere black belt in the reed to reduce the vibration of dents teeth and prevent the reed jet airflow diffusion.

Bending broken weft of air jet loom

Weft is U-shaped bent due to insufficient weft insertion, poor openings and weft arrival delay. Thus the air jet loom stops or has double-thin weft defects.


(1) The main nozzle jet time and electromagnetic needle functioning time are improper.

(2) In the shear, weft runs out from the electromagnetic needle.

(3) The compressed air pipeline leaks.

(4) The auxiliary nozzle pressure is too low.

(5) Loom openings are faulty, there is warp hairiness, knot head, fly and other yarn defects.

(6) Opening is too small or opening time is not standard.

(7) The warp yarn hits the auxiliary nozzle tip.

(8) Warp tension is too small.

(9) The main nozzle position is wrong.

Elimination methods

(1) Advance or delay the opening time of the electromagnetic needle and the main nozzle jetting time.

(2) Adjust the left scissors, yarn guide action time, in order to reduce the cutting resistance; or appropriately improve the shear blowing pressure.

(3) Check the bending or leaking mechanical valves and trachea, to adjust or replace.

(4) Appropriately improve the auxiliary nozzle pressure.

(5) Strictly follow the provision that the warp joints should be less than 3mm, to remove the large joints, feather yarn and fly attached and other warp defects.

(6) Increase the amount of openings, check and adjust the opening time.

(7) Move the auxiliary nozzle by 0.1 ~ 0.2 unit, and check whether the auxiliary nozzle tip is smooth.

(8) Measure and increase warp tension.

(9) Correctly adjust the position with the main nozzle gauge.

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