Gear hobbing machines provide gear manufacturers a fast and accurate method for cutting parts. This is because of the generating nature of this cutting process. Gear hobbing is not a form cutting process, such as milling where the cutter is a conjugate form of the gear tooth. The hob generates a gear tooth profile by cutting several facets of each gear tooth profile through a synchronized rotation and feed of the work piece and cutter.
As the hob feeds across the face of the work piece at a fixed depth, gear teeth will gradually be generated by a series of cutting edges, each at a slightly different position. The number of cuts made to generate the gear tooth profile will correspond to the number of gashes of the hob. Simply put, more gashes produce a more accurate profile of the gear tooth.
The hobs several cutting edges will be working simultaneously, which provide significant potential for fast cutting speeds and/or short cycle times. With this realization, one can see the hobbing process’s advantage over other cutting processes.