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Broaching is a machining technique used to remove unwanted metal from a workpiece. Flat, round, and contoured surfaces can all be machined using this kind of manufacturing process, as well as internal and external surfaces.
The cutting tool used in the broaching process is aptly named a "broach." It works by being pushed or pulled across the piece being machined to remove small amounts of material with its teeth. Each tooth on a broach is progressively longer which creates chips that vary in size to ensures a smooth-finished product. Cutting may be accomplished either on a vertical or horizontal plane.
Broaching is most frequently used by manufacturers for producing internal shapes. Keyseats are the most common example of this. A keyseat, or keyway, is a rectangular groove that is axially located in a shaft or hub. Keyseats are used for a variety of purposes such as preventing rotation.
An arbor press can be used to broach keyseats in hubs of gears and sprockets by pushing the broach through a workpiece. Without the press, the final product may not be precise enough to ensure a good quality fit.
Broaching has many advantages. Not only does it allow for high production levels, but it creates close tolerances, as well. The best broaches today are fabricated using Computer Numerically Controlled (CNC) grinders which help keep broach teeth tolerances very low.
Broaching also allows for high quality surface finishes while offering lower manufacturing costs in the long run because lower-skilled workers can operate the automated equipment. Moreover, since broaching only removes minute quantities of material, the broach generally will last longer than other tools.
Broaching lowers costs to manufacturers while offering the fastest way to remove metal and providing quality workmanship without the need for specialized training.