1. What is the impact of the timing of weft insertion?
① Early weft insertion time leads to early weft arrival time and low air consumption. However, when it is too early, insufficient opening amount can cause the weft to hang and cause weft to stop;
② If the weft insertion time is delayed and the weft yarn arrival time is delayed, it is necessary to increase the airflow pressure of the main and auxiliary nozzles to reduce weaving defects such as right weft shrinkage, which will increase the air consumption;
③ When the warp conditions are good and the opening is clear, the weft insertion time can be advanced, otherwise the weft insertion time should be mastered slightly later.
2. What is the reason for the side weft shrinkage of the yarn supply?
① The pressure of the main nozzle and auxiliary nozzle is too low, and the weft conveying force is too weak;
② There are flying debris blocking the main nozzle, resulting in low actual air pressure and flow rate;
③ There is air leakage in the main nozzle or auxiliary main nozzle air pipe;
④ The weft yarn has many hairiness and high twist;
⑤ If the shear pressure is too low, the weft yarn rebounds;
⑥ The warp yarn on the supply side is loose.
3. What is the reason for the side weft shrinkage of waste edge yarn?
① The opening angle is too early, and the weft end cannot be straightened when the weaving mouth is closed;
② The air pressure of the main and auxiliary nozzles is too low, resulting in slow and unstable weft flight speed and low weft tension;
③ Improper height of the heald frame affects the flying speed of the weft yarn, resulting in weft shrinkage;
④ Improper timing of the main nozzle and auxiliary nozzle resulted in the weft yarn flying in a relaxed state;
⑤ There is leakage or blockage in the main and auxiliary nozzles and air ducts;
⑥ Excessive distance between several auxiliary nozzles at the end;
⑦ Left side scissors cut too early, resulting in poor cutting;
⑧ The right side twisted edge yarn has poor twisted edges, or the waste edge yarn is poorly woven and cannot hold the weft yarn, causing the weft yarn to rebound and cause weft shrinkage;
⑨ The twist of the weft yarn is large and unstable, and the twist back elasticity is too large; The moisture regain of the weft yarn is too low, the tension is low, and it is easy to pick up loops, causing weft shrinkage;
⑩ The weft yarn is unevenly wrapped on the weft storage device, and the timing of the pick and drop of the yarn blocking magnetic needle is not properly matched with the spraying time.