On The State Of Filling Movement During Weft-insertion On Air-jet Looms

After rapid development of the last several decades, weft-insertion system of domestic air-jet looms has been obviously improved, However, there is a big gap between domestic and foreign air-jet looms in some fields such as weaving speed and weaving efficiency, one of the foundations to narrow the gap is to make the filling movement rule of the weft yarn more clearly during weft inserting, and the relationship among weft yarn's speed, headend wave state and weft inserting parameters. It has an important theoretical significance and practical value to carry out the studying of this area as for improving weaving efficiency and optimizing the weft- insertion system of domestic air-jet looms.Regularities of filling movement state distribution on Dornier AWV8/S and TaiTan TT-800 air-jet looms were tested and analysed through segmentation-splicing method with high speed camera system. Meanwhile, combining with the partial tracking and overall evaluation method, the weft yarn's headend wave state were described and symbolized.Later, the influence of weft- insertion process parameters on filling movement state of air-jet looms was researched and analysed.Finally,the optimal combination of weft inserting was explored by using five factors five levels orthogonal experiment.The main conclusions are as follows:(1)Weft yarn's speed of TaiTan TT-800 air-jet loom was keeping increasing during the whole process of weft-insertion and when up to the maximum, the speed began to appear sharply declining till the weft inserting end. Besides, the weft yarn's velocity distribution of Dornier AWV8/S air-jet loom can be divided into four stages: the initial stage of rapid acceleration, the front middle stage of smooth acceleration, the later middle stage of smooth deceleration and the late stage of rapid deceleration.(2)The local tracking method is helpful to understand the weft yarn's headend floating condition, and the whole evaluation method can be used to characterize the weft yarn's headend volatility. Moreover, the fluctuation in different fineness of cotton yarn on Dornier air-jet loom was tested and analysed so that the weft yarn's headend volatility in the reed decreases with the increase of weft yarn count and the filling movement of weft yarn is more stable.(3)Weft yarn gains a high speed and a good headend floating condition when its count is 41~S and 80~S; The air pressure of main nozzle should be choosed at 0.35 MPa when the fluctuation requirement of air-jet loom is not demanding. Therefore, it can meet the demand of weaving efficiency and air consumption; The weft yarn headend motion is more stable and the weaving cost is lower when the distance between main nozzle and the first assistant nozzle is set at 25mm; Principle of assistant nozzles'installation height is selected under the condition of which the weft yarn fluctuation can meet the actual opening requirement, and assistant nozzles'installation height should be choosed as high as possible. When installation angle of assistant nozzle is below 4°, it can be improved in the reed groove between assistant nozzles'airflow and the weft- insertion airflow by increasing installation angle. On the contrary, when the angle is above 4°, increasing the angle will worsen the effect of airflow synthetic, which is unhelpful to high speed and efficiency of air-jet loom.(4)The primary and secondary sequence of the 5 factors of weft-insertion is: the main nozzle's air pressure E>weft yarn count A>assistant nozzles'installation height B>assistant nozzles'installation angle C>the distance between main nozzle and the first assistant nozzle D. The best combination of weft insertion factors is as follows: main nozzle air pressure is 0.45 MPa, weft yarn counts is 80 S, assistant nozzles'installation height is the 4th line, assistant nozzles'installation angle is 5°, the distance between main nozzle and the first assistant nozzle is 25mm.The research and conclusions in this paper have an important referential value to air-jet loom in making the filling movement rule of weft yarn clearly during weft-insertion, optimizing weft-insertion parameters and improving weaving efficiency of air-jet looms.