A fiber made from a natural or synthetic high molecular material. Depending on the source of the raw materials, it can be divided into rayon fibers using natural polymer materials as raw materials and synthetic fibers using synthetic polymer materials as raw materials. Chemical fiber is usually prepared by making a natural or synthetic polymer material or inorganic material into a spinning melt or solution, and then filtering and metering, and extruding it into a liquid stream by a spinneret (plate), and then Solidified into fibers. The fiber at this time is called nascent fiber, and its mechanical properties are very poor. It must undergo a series of post-processing steps to meet the requirements of textile processing and use. Post-processing mainly involves stretching and heat setting the fibers to improve the mechanical properties and dimensional stability of the fibers. Stretching is the orientation of macromolecules or structural units in the nascent fibers along the fiber axis; heat setting is primarily to relax the internal stresses in the fibers. Post-processing of wet-spun fibers also includes processes such as water washing, oiling, and drying. When the filament is spun, it can be wound into a cylinder through the above steps; when spinning the short fiber, it is necessary to increase the steps of curling, cutting and packing.