Gear Cutting

the process of machining the teeth of gears and other parts with teeth on a gear-working machine by removing shavings with a gear-cutting tool. Gear cutting can be rough (preliminary) or finished. In rough gear cutting, much of the allowable material is removed, but the profile of the gear tooth does not receive its final shape. Finishing work can be the final process, or it can be followed by a hardening treatment of the gear teeth, a heat treatment followed by grinding or polishing. Rough cutting is done by generating or forming, and finishing work is usually done by generating. In forming, the tool used is a disk or finger cutter, which in the radial plane has a profile corresponding to the depression between the teeth of the gear being cut. Generating uses hob cutters, rack-type gear-planing cutters, slot-cutters, and gear-grinding cutters with a cutting part whose working sur-face is like the profile of the tooth of the gear rack (wheel) to which it is coupled. The profile of the tooth obtained after cutting by the generating method is close to the envelope line formed by consecutive positions of the cutting edge of the cutting tool.