For example, if a spur gear is being produced, the spindle is held at the lead angle of the hob, whereas if a helical gear is being produced, the held at the lead angle of the hob plus the helix angle of the helical gear. The angle between the hob's spindle (axis) and the workpiece's spindle varies depending on the type part being manufactured.
One is mounted with a blank workpiece and the other holds the cutter (or “hob”). A hobbing machine uses two skew spindles. Hobbing can create gears that are straight, helical, straight bevel, faced, crowned, wormed, cylkro and chamfered. Process Spur gears on horizontal CNC gear hobbing machine Spur gears on horizontal CNC gear hobbing machine Ī type of skiving that is analogous to the hobbing of external gears can be applied to the cutting of internal gears, which are skived with a rotary cutter (rather than shaped or broached).
Hobbing is especially common for machining spur and helical gears. Hobbing is relatively fast and inexpensive compared to most other gear-forming processes and is used for a broad range of parts and quantities. The teeth or splines of the gear are progressively cut into the material (such as a flat, cylindrical piece of metal or thermoset plastic) by a series of cuts made by a cutting tool called a hob. Hobbing is a machining process for gear cutting, cutting splines, and cutting sprockets using a hobbing machine, a specialized milling machine.
