Polyester monofilament main production by one-step production process and two-step production process. By spinning at high speed and high speed tensile twisting technology, is a classic two-step route, is the production of polyester filament with most routes. Characterized by a short process flow, the production efficiency is high. 3000~600m/min high speed spinning spinning speed can make POY (POY). At high wind speeds, the orientation of the fibers have a certain structure is stable. Lashenjia-twist polyester filament production is essential operations, called the secondary forming. Stretching the fiber units access to stable and stable orientation, in order to improve the finished product physical-mechanical properties of fibers.