Climb Hobbing And Coventional Hobbing

Climb Hobbing And Coventional Hobbing

Climb Hobbing And Coventional Hobbing - In climb hobbing the direction of rotation of the hob coincides with the direction of work feed. In conventional hobbing the hob rotates in a direction opposite to that in which the gear blank is fed (refer Fig.).

Climb hobbing is more efficient than the conventional kind because it provides for more favourable conditions of chip formation, less variation in the cutting forces and less vibration in hobbing. These features lengthen hob life and improve the finish of the machined surfaces.

Climb Hobbing	Conventional Hobbing

For cutting helical gears on the hobbing machine, the hob is set at an angle with respect to tbe end face of the gear equal to the sum of the helix angles of the thread on the hob and teeth on the gear (if the hands of the hob thread and gear teeth are the opposites and equal to the difference of these helix angles if the hands are the same.

As regards advantages and applications of gear hobbing, it is the most used method of making gears. It is fairly quick to set up; therefore, it is economical for short or long runs. The smooth cutting action makes it possible to generate quite accurate gears, and one hob can be used to cut spur and helical gears of different angles.

Hobbing can also be used to make worm gears, sprockets, splines etc.As regards its limitations, hobbing cannot be used to cut internal gears or where flanges etc., might interfere with the hob.