The Hollow Spindle Spinning Theoretical Research

Hollow spindle spinning is also called parallel spinning or wrap spinning. It is a kind of new spinning methods. With an untwisted parallel fiber strand as the core yarn, the filament package or yarn package which is fixed to the spindle rotates at a high speed, meanwhile the filament or yarn untwists from the package and wraps on the core yarn to form the hollow spindle spinning yarn which has a unique yarn structure. As the new material and technology is becoming plentiful, the hollow spindle spinning product is getting rich. Except for the traditional styles of filament wrapped staple yarn and filament wrapped filament yarn. We can get beautiful fancy yarn and spandex wrap yarn which has a great financial interest.During hollow spindle spinning, the yarn package rotates at a high speed, yarn untwists from the package and forms a balloon. The yarn balloon phenomenon exists commonly in spinning processes. The shape of yarn balloon is a general displacement of the forces acts on the balloon yarn. There is a close relationship between the yarn balloon shape and the forces acts on the balloon. The balloon shape is decided by the spinning force, on the contrary, we can find the value of the spinning force according to the yarn balloon shape. To a great extent, the spinning tension impacts the yarn structure and quality. It is difficult to measure the spinning force value directly. By observing the yarn balloon shape, we can evaluate the spinning tension.In this article, we chose balloon phenomenon of the hollow spindle spinning as research object. Take photos of the real yarn balloon with a developed digital camera, analysis the forces acts on the balloon yarn, and build yarn balloon model. We start from the plain balloon research, and further, we analyze the yarn balloon considering the Coriolis force and the Air drag force respectively in right-angled coordinate and cylinder coordinate system. We got differential equation sets according to second law of Newton. Put appropriate initial value gained from the digital photo samples into the equations. And with help of the Mathematic software, we can get the numerical value solution, also we can get the 3D simulated figure and the projection figures in three coordinate axis. As the spinning technological parameters are a little bit more, we can get relationship between the spinning force and the technological parameters qualitatively by analysis the balloon model, which can provide a direction for changing the parameters and improving the spinning machine.