HI Wangyangzhong
according to my experiance, you need to search and download an autolisp file. By that you can enter number of teeth and module, then it will create a profile of gear teeth in AutoCAD. Than you can export it to dxf and use on that machine. Some machines has gear command in its own builtin CAD, for others this method works. If you dont find it on any mcad forum, please email me, I will try to search and email you.
I have an another method, I have a perametric file for Catia. We can make any number of teeth and module gear in 3D with it. Some times, we make its dwg then export it to dxf and use on wirecut. If you have access to Catia, I can give that file or I can give perticuler dxf if you need. Please tell me.
Anyone can email me regarding this gear.