The main function of the transmission element is to transmit speed and torque in the mechanical system. In the past few decades, the development of engineering plastics and high-tech polymers has made plastic spur gears not only have high mechanical strength, but also maintain the inherent advantages of plastic materials:-good corrosion resistance and chemical resistance;-High torsion resistance and tensile strength;-Reduce noise;-Small friction coefficient, can be used in application conditions where transmission components are difficult to lubricate or prohibit lubrication.