Large gears generally refer to gears with gear modulus > 16 mm, which are widely used in heavy machinery such as engineering machinery, mining, metallurgy and so on. There are many kinds of large gears, such as spur gear, arc gear, bevel gear, etc. At present, there are two main machining processes of large gears: forming method and generating method. The principles, advantages and disadvantages of the two processes are shown in the table.
| Project | Forming process | Development process |
| Principle | The forming tool is used to cut the tooth profile directly on the tooth blank to be machined | Using the meshing principle of tooth profile to cut gears |
| Advantage | It is processed on ordinary milling machine and has strong universality | High efficiency, high precision, suitable for mass production |
| Disadvantage | Each tooth needs to be processed one by one, which has low efficiency and is easy to cause machining errors such as tooth shape and size | Environmental restrictions, can only be carried out on professional CNC machine tools, and the processing price is high |
| Processing method | Gear milling and gear grinding | Gear hobbing, gear shaping and gear grinding |
The above large gear forming method is studied. NC machining process flow based on forming method. Based on the basic technological process, the machining technological process of large gear is analyzed in detail.