Production Broaching
In the case of production broaching, many work-pieces are machined at once, a process that takes seconds to complete. Since broaching requires no secondary operations and the machining process is so short, producing high volumes of industrial products like pulleys, gears, sprockets and the threading on screws can be done very quickly. Broaching machines are considered special purpose machinery because they are confined to very limited capabilities; many can only produce one or two different holes or groove shapes. For this reason, facilities that use broaching machines usually specialize in a certain type of broaching, including
blind broaching,
internal broaching or
rotary broaching. These processes machine work-pieces, usually made out of softer metals like aluminum, copper and brass, that when finished are used within the automotive, machinery, aerospace, commercial and military industries. Broaching machines produce several different shapes in metal, which alter the surface or are drilled straight through. These include hexagonal, square, round, slots, splines and the most widely used, a hole with a keyhole-shaped profile called a keyway.
Broaching is accomplished several different ways, including pull broaching and push broaching. When a work-piece is pull broached, the broach tool, which is a long, thin tool with successively larger teeth, is pulled through the part in a single pass. It can also be pushed through. Rotary broaching is done on a lathe and the tool revolves at high speeds. Some broaching processes like
pot broaching reverse the motion and while the tool remains stationary, the work-piece is moved with high force through it inside of a hollow housing called a pot. Larger broaching job shops contain several of these machines, which are also able to stamp, cast and forge the work-pieces. While there are many different methods and styles of broaching, the main idea remains constant. Every broaching machine, whether vertical or horizontal, contains one or more broach tools that contain teeth that cut out pieces of metal on the interior or exterior of the metal work-piece. They are automated and sometimes even part of a conveyor line system.
