The generative method uses tools and gears to form a generative motion to process gears. There are mainly gear hobbing and gear shaping. Gear hobbing is processed by simulating the meshing of worm gears. Gear shaping is processed by simulating the meshing of two gears. Rolling Tooth is used a lot, because the tooth profile of the hobbing cutter is a linear spindle, which is convenient for processing, and the gear shaping tool is a gear with a shovel back, and the tooth profile is involute, which is not as convenient for machining. But gear shaping. It can be used in some positions where hobbing cannot be processed, such as double or multi-connected gears with internal teeth and short retracting distance. In the finishing of gears, there are gear shaving and gear grinding. The same is the generative method, the gear shaving The advantage is high efficiency but cannot be used for hard tooth surfaces. Grinding is the opposite