On Mechanism And Technology Of Spinning Segment Colored Yarns With Uniform Linear Density

The segment color yarn with uniform linear density, as a kind of fancy yarn, can achieve not only a variety of colors within the same cross-section of a yarn, but in the length of the yarn can also be achieved with irregular distribution segment changing combination. Due to its unique yam structure and segment color changing effects, it is widely used in woven fabrics, suits, jackets, shirts, and its knitted production can be widely used in knitted sweaters. Besides, it’s also heavily used to the production of hats, scarves and home textile products. Therefore it could be widely used. The yarn is produced by the three with axis four roller spinning production, which is designed by our team. According to test spinning of practical experience, the segment color yarn produced by the device could be designed and diversified production. But the quality of its yarn is unstable and easily broken.Therefore; the paper will study it in two aspects:one is the spinning mechanism and process optimization.The line density segment color yarn’s quasi-static model, which based on theoretical study of siro-spun, is established. The model is used to study the relationship between the stability of convergence point and spinning tension, roving torque and roving ratio, which are closely with yarn twist, the draw ratio, spinning speed and the composition ratio of the yarn. Based on quasi-static model, the concept of quality control body is introduced. The assumption is that the amount of inflow and outflow in quality control body is equal and the yarn always maintains the circular cross-section. Under this assumption, the kinetic equation is listed by the law of conservation of momentum of fluid dynamics. The convergence angle formula is derived through equations. By experimental verification, the theory can be partly correct.The next is the process improvements and optimization. Based on experience and theoretical analysis, the single factor experiment is made. Through this experiment, the key factors affecting its quality of yarn could be obtained.It is twist, spindle speed and in the composition ratio of two roving in the yarn. The optimal range of these key factors is drawn by the experiment. According to the optimal range, three rotary combination experiments is designed in order to get the optimal process parameters. The optimal process parameters are that yarn composition ratio’s28.901%, yarn twist is804, and spindle speed is4671r/min.Due to inconspicuous segment color effect and inconsistent quality of yarn,the spinning device is successfully reformed in order to produce good quality yarn.The difference is that there are two middle rollers which is corresponding to two back rollers and a stacking device at the front roller. These changes are beneficial to improve the yarn evenness and to control the roving at the front roller. The segment color yarn produced by transformed device has a clearer segment effect and better yarn quality.