Helix gash of hob cutter manufactured by milling

Hob cutters with a helix gash are frequently used in worm-type and straight-sided hob cutters with large lead angles. A milling cutter is the main tool in the manufacture of gashes of hob cutters. However, if a hob cutter has helix gashes, the actual cutting faces may deviate from the theoretical form due to generation motion. Sharpening errors can also contribute to both profile and lead errors if the work piece is exposed to the cutting edge in a different plane. In this paper, the mathematical models of the theoretical and the actual gashes manufactured by milling cutters are developed. A numerical example is also given to demonstrate the significance of profile deviation of the cutting faces. The models can be used to predict actual cutting profiles and assist in the design and manufacture of high precision hob cutters.