Air Jet Loom weaving common grey fabrics mainly has weft, hundred feet, double weft and thin dense roads. It is no problem to improve the weaving efficiency of air jet loom by analyzing the causes of weaving.
1, weft
Causes:
(1) The quality of the original yarn: the yarn twist is too large, the free end is seriously untwisted, and the weft yarn is unstable and the weft is generated; the yarn has a long hairiness and a large knot, and the weft yarn end is in a swimming state once the weft yarn is feathered. When it is rubbed against the warp, it is easy to form a entanglement, causing weft.
(2) Quality of semi-finished products: the quality of the weaving shaft is poor, the openings are unclear due to sticking, and twisting, and the weft movement is hindered, especially the loosening of the weft-inserting.
(3) Mechanical state: The compressed air is not pure, and it is easy to cause the air passage to be blocked, so that the supply air pressure is unstable, and the weft yarn is not straight and the weft is formed. Leakage of gas components such as gas pipes, joints, and regulating valves causes the air pressure to be unstable, which affects the normal flight of the weft yarn.
(4) Unclear opening: Even extremely slight yarn slack and interfiber adhesion can hinder the weft flight and form a weft.
(5) The weft insertion process is unreasonable: the yarn release needle release time is improper, the nozzle solenoid valve opening and closing time is not accurate, the nozzle pressure is too high or too low, causing the weft yarn to be squeezed before the flight, and the weft yarn cannot fly straight through the shed. The weft is caused; the right side of the hinge is closed late, the weft is not caught in time, and the weft is retracted. The weft shrinkage caused by the unreasonable weft insertion time: the weft insertion is too early, the opening height is not enough, and the weft shrinkage is likely to occur due to the poor weft flying due to the warp hairiness and other defects; otherwise, the weft insertion is too late and the weft yarn arrives. The angle is late, the opening height is relatively small, and the head end of the weft yarn collides with the warp yarn, causing the weft yarn to be blocked to form a weft. In addition, the injection time is improperly matched. When the weft yarn reaches a certain place, the auxiliary nozzle solenoid valve is not opened in time, causing the weft yarn to fly in a relaxed state to form a weft.
(6) Workshop temperature and humidity: The temperature and humidity of the workshop are low, the elasticity between the fibers is relatively enhanced, and the friction is reduced, which promotes the increase of the back-twisting torque.
solution:
(1) Generally, when the weft yarn strength meets the weaving requirements, the smaller the twist factor should be selected as much as possible, and the polyester-cotton fabric should be improved in the setting effect; the optimal twist is designed to reduce the unevenness of the twist; the knotless yarn is used; Appropriately delay the opening when the tightness is not large.
(2) The warp tension of warping should be 2~3 g, strictly control the sizing yarn side head, and correct the distance of the disc board opening to ensure the matching of the disc opening and the web.
(3) The compressed air is impure. Double-layer filter can be installed at the air inlet. The filter is cleaned and maintained regularly. If there is moisture on the cloth surface, check whether the drying system is running normally. In daily maintenance, carefully use the ultrasonic vibration meter. Clean the solenoid valve.
(4) The heald frame and opening stroke must be adjusted according to the process requirements at the beginning of the machine, and the consistency of the process on both sides of the heald frame should be paid attention to when adjusting the heald frame. On the air jet loom with the opening of the tread plate, the wire rope is a flexible carrier for lifting, which is easy to pull down in the moving state. Generally, the height of the heald frame is checked once a week, which can not only eliminate the influence of the elongation of the wire rope, but also eliminate the running repair machine. Due to frequent on-board, bad car repair, and improper adjustment, the workers and the mechanics are caused by the unevenness of the heald frame or the incorrect height.
(5) Make sure the yarn guide channel is clear. Check the steel shovel for severe scarring and bending.
(6) The process design should be reasonable, and the injection time of the last set of auxiliary nozzles should be appropriately extended, and the opening time of the right side hemming device should be appropriately advanced, and the head end of the weft yarn should be clamped in time.
(7) The temperature and humidity of the workshop are unstable, which makes the warp and weft yarn performance change, affecting the clarity of the shed. It should be adjusted in time. The general air jet loom temperature is 22-26 °C, and the relative humidity is between 72% and 78%.
2, hundred feet
Causes:
The original yarn is insufficiently strong, and the thickness of the yarn is not uniform; the blown yarn is not subjected to H2, that is, H2 does not receive the weft pulse signal, and the weft yarn has passed H1, so the weaving machine operates normally, generating a hundred feet; The weft is dirty, the sensitivity is reduced, and a hundred feet are generated; the main nozzle has a large atmospheric pressure, and the weft yarn is blown in the main nozzle. When the first weft is driven, a weft is formed on the right side of the cloth surface, and the main and auxiliary nozzles have a large pressure. The detail of the weft yarn was blown off; the operator did not perform the operation as required when handling the stoppage, for example, the broken weft that was extracted was not pulled out and caused a hundred feet.
solution:
Generally, the twist coefficient of the weft yarn is relatively small, the strength of the yarn is low, and the twist is increased by 5% to 9%, which can effectively reduce the break of the weft yarn. The use of the rotor spinning can effectively reduce the details of the yarn; and strengthen the repair of the weft insertion device. In time, clean the fly flowers generated by the H1 and H2 weft detectors; reduce the normal pressure of the main nozzle, and control the nozzle pressure to be small when the weft yarn can pass smoothly; strengthen technical training, improve the responsibility of the work of the vehicle operator, and strictly enforce the operation method.
3, double weft
Causes:
When alternate weft insertion, the first weft yarn on the other weft feeders is introduced into the weaving woven fabric, and a double weft point of about 30 cm is formed on the left side of the cloth surface. The analysis shows that there are mainly the following reasons: The decoupling of the weft yarn: the rebound spring of the weft feeder yarn is invalid, which causes the yarn opening needle to fall in an inaccurate and unstable angle. The weft yarn is easy to escape from the yarn retaining needle; the yarn retaining needle is not worn in the middle and encounters the yarn storage drum. Upper, the weft yarn slides out from the storage drum; the distance between the weft feeder and the pressure increasing nozzle is too close, and when the weft yarn is retracted from the weft feeder, the yarn loop is drastically shaken, and it is easy to be pulled out from the yarn retaining needle; Failure to align with the center of the weft feeder, the yarn loop is irregular, and the position angle to the main nozzle is not correct, causing the weft tension to be unstable when the scissors are shearing, and the weft rebound is ejected from the yarn feeder needle; the left scissors The blade is loose, the yarn cutting time is unstable, the cutting edge is not sharp, and the weft yarn is broken to cause the weft rebound to be intensified.
solution:
Replace the weft feeder yarn retaining spring, lightly wipe with lubricant; replace the yarn retaining needle; adjust the distance of the weft feeder to the boost nozzle or install the balloon rupture device; adjust the height and angle of the weft feeder to the appropriate position; Replace the repaired left scissors and press the forward button to check that the weft yarn is not pulled when the yarn is cut.
4, thin road
Causes:
(1) The displacement of the weaving mouth. When the loom is stopped, both the fabric surface and the warp yarn are subjected to a large upper machine tension, and at this time, the weaving opening is separated from the steel reed, and the weaving opening is deviated from its corresponding position during normal weaving due to creep and slack of the warp yarn. The amount of deviation varies with the length of the stoppage time. When the vehicle is re-driving, if the position of the weaving mouth is not handled properly, a dense road is formed on the cloth surface. In addition, there are many idle speeds of the idle train, and the tension of the sling ring and the winding tension of the take-up mechanism are insufficient, and the weaving mouth is also displaced.
(2) The device status is bad. As the loom continues to operate for a long period of time, some mechanical parts and components gradually wear out or even fail, and the motion accuracy is degraded, or the first wefting power of the first weft is insufficient after driving, and the first weft is not fully driven into the weaving mouth; Or the brakes are not timely when the yarn is broken, and there are vacancies in the weft yarn and the failure of the take-up and take-up.
solution:
(1) Reduce the frequency of parking. When the loom is stopped within 3 min, there is no thin road, and there is a dense road defect within 5 min. After 10 min, there is a clear and dense road defect. Therefore, stopping the car is the most important cause of the dense road. Improving the quality of semi-finished products to reduce the stoppage is the most effective measure to reduce the density of the roads; in the production, the blockers should handle the stoppages in time to prevent the formation of the dense roads; or arrange the weft break automatic processing device to shorten the weft stop Time, eliminate the thin road.
(2) Equipment maintenance. After the weaving shaft of the shaft head wears on the vehicle, the overall weaving of the weaving shaft during the production operation seriously damages the weaving shaft bearing, which is easy to cause the dense road weaving. The rough surface rubber skin of the take-up friction roller is used for a long time and wear, the surface roughness of the rubber skin is gradually reduced, and the friction coefficient with the cloth surface is reduced. During the rotation, the slippage between the cloth surface and the roller sometimes occurs, and the cloth surface is formed. The phenomenon that the two ends are normal and the middle is obviously densely woven, which affects the production quality. Therefore, the failed rubber skin must be replaced in time.
(3) Optimize process parameters. The symmetrical shed has a low warp tension when the shed is fully opened, which can reduce the dense road, but the fabric style is poor. The rearward position of the rear beam is rearward, and the rear warp of the shed, especially the upper warp yarn, the lower the tension peak at the time of opening, the smaller the tension change, the less dense the road, but the rear sill is increased. The height of the warp stop should be slightly lower than the warp position of the flat heald, and it can be appropriately lowered during the weft, and it can be raised appropriately when the road is closed. The front and rear positions of the warp stop determine the length of the rear warp of the shed. The rear stop frame also helps to reduce the warp tension peak at the time of opening and reduce the dense road. During the opening process, the opening stroke is small and it is not easy to produce a dense road. The opening time is set according to the density of different fabric tissues and warp yarns. The earlier the opening, the tighter the warp yarn during beating, which is advantageous for beating the general heavy fabric. In addition, if a dense road occurs, the amount of reversal of the weaving shaft before driving is reduced; if a thin road occurs, the amount of reversal of the weaving shaft before driving is increased. After setting the parameters according to the above method, the loom can enter the normal weaving operation program. The tension on the machine is not enough. After the beating is finished, the weaving mouth moves backwards, causing a thin road.
