In the process of synthetic fiber imitation of natural fiber, people use non-round spinneret to produce a variety of different cross-sectional shape of the fiber or hollow fiber, in order to improve the feel of the fiber, resilience, pilling, fluffiness, gloss and other properties. This kind of fiber is called shaped cross-section fiber, referred to as shaped fiber.Shaped fiber cross-section into a special shape, not like the general chemical fiber as round or nearly round. According to its cross-section shape, shaped fiber can be divided into triangular, trilobal, cruciform, polygonal, multilobal, hollow fiber and other types.