Common defects in fabrics produced by air-jet looms are mainly weft shrinkage, hundreds of feet, double wefts, sparse wefts, etc. These common weaving defects are the main factors that affect the weaving efficiency of air-jet looms. Netizens analyzed the causes of these defects and proposed corresponding solutions, hoping to provide some inspiration to everyone.
01 Weft shrinkage
Causes
Improper release time of the yarn blocking needle, inaccurate opening and closing time of the nozzle solenoid valve, and too high or too low nozzle pressure will cause the weft yarn to be crowded before and after flying, and the weft yarn cannot fly straight through the shed. Weft shrinkage; the closing time of the right hem is too late, the weft yarn is not clamped in time, and the weft yarn retracts; the weft insertion time is too early, and the opening height is not enough, which increases the weft shrinkage; conversely, the weft insertion time is too late, the weft yarn reaches the angle late, and the opening height Relatively small, the head end of the weft yarn collides with the warp yarn, causing the weft yarn to be blocked and cause weft shrinkage. In addition, improper injection time can also cause shrinkage.
The temperature and humidity in the workshop are relatively low, the elasticity between fibers is relatively enhanced, and the friction is reduced, resulting in an increase in reverse twisting torque Form shrinkage.
Solutions
If the compressed air is impure, a double-layer filter can be installed at the air inlet. The net and filter should be cleaned and maintained regularly; if moisture appears on the cloth surface, check whether the drying system is operating normally; in daily maintenance, the solenoid valve should be carefully cleaned with an ultrasonic vibrator.
At the beginning of machine installation, the heald frame and shedding stroke must be adjusted according to the process requirements, and when adjusting the heald frame Pay attention to the consistency of the workmanship on both sides of the heald frame. On air-jet looms with pedal openings, the steel wire rope is a flexible carrier for lifting the healds and is easy to be stretched during movement. Generally, the height of the heald frame is checked once a week. This not only eliminates the impact of the stretched wire rope, but also eliminates the need to run the repair machine. The weft shrinkage caused by uneven heald frames or incorrect heights caused by workers and machine workers frequently working on machines, repairing broken machines, and improper adjustments.
The temperature and humidity in the workshop are unstable, which changes the performance of warp and weft yarns and affects the shedding clarity. It must be adjusted in time. Generally, the temperature of air-jet looms is 22℃~26℃, and the relative humidity Between 72% and 78%.
02 Double weft
Cause
Weft feeder yarn blocking needle The rebound spring fails, causing the opening and falling angle of the yarn blocking needle to be inaccurate and unstable, and the weft yarn easily falls out of the yarn blocking needle; the yarn blocking needle is worn out of center and hits the yarn storage drum, and the weft yarn slips out of the yarn storage drum; The distance between the weft feeder and the booster nozzle is too close. When the weft yarn is withdrawn from the weft feeder, the yarn loops swing violently and are easily thrown out from the yarn blocking needle; the booster nozzle fails to align with the center of the weft feeder, and the yarn loops are not Rules, and problems such as incorrect position and angle to the main nozzle will cause double weft defects.
Solutions
Replace the yarn blocking needle spring of the weft feeder; replace the yarn blocking needle; adjust the weft feeder to pressurized The distance between the nozzles or the installation of a balloon breaker; adjust the height and angle of the weft feeder to the appropriate position; replace and repair the left scissors, press the forward button to check, and there should be no weft nap when shearing.
03 Baijiao
Cause
Generally, the twist coefficient of weft yarn is relatively Smaller, the strength of the yarn is lower, the twist is increased by 5% to 9%, which can effectively reduce weft yarn breakage. Using rotor spinning can effectively reduce the details of the yarn; strengthen the maintenance of the weft detector and clean the weft detector in time. The flying flowers produced; reduce the normal pressure of the main nozzle, and control the nozzle pressure to a small value when the weft yarn can pass smoothly; strengthen technical training, improve the work responsibility of the stopper, and strictly implement the operating method.
Solutions
Reduce the frequency of shutdowns. Shutting down vehicles is the main cause of dense roads. Improving the quality of semi-finished products to reduce vehicle shutdowns is the most effective measure to reduce defects on dense roads. During production, workers should handle the stoppage in time to prevent the formation of dense road defects; or configure an automatic weft breakage processing device to shorten the weft stop time and eliminate dense roads. </p
