There are two common processing principles of gears, profiling and Fan Cheng (generating) processing.
1. Copy processing.The gear machining tool cuts out the tooth slot of the gear, and the "cross-sectional shape" of the tool is the shape of the tooth slot of the gear.When machining gears, there is no gear meshing movement, and the precision of the processed gears is low, generally below grade 11.
2. Fan Cheng processing.The gear machining tool itself is a "gear or rack", and the gear hob can "think" as a rack, which is a rack type tool.During machining, there is a "gear meshing" movement between the gear tool and the gear being machined.The tooth profile blade of the gear cutter, which moves to envelop the tooth profile (tooth surface) of the processed gear, is an ideal involute with high machining accuracy. .