The term broaching may have been derived from an ancient roman word braccus, which meant an object having projecting teeth. The operation started in the year 1850 when broaching tools were called “drifts”. These drifts were being hammered in blacksmith shop through the work or pushed through with an arbor press.
Broaching is a method of removing metal by pushing or pulling a cutting tool called a broach. The tool may be pulled or pushed through the surface to be finished. Surface is finished by broaching flat or contoured and may be either internal or external. Broaching is generally limited to the removal of about 6 mm of stock or less. Different types of broaches are used for different types of work.
Broaching machines are probably the simplest of all machine tools. These consist of a work holding fixture, a broaching tool, a drive mechanism and a suitable supporting frame. Although the component is a few, several variations in design are possible. There are two principal types of machines, horizontal and vertical type. In addition to the standard types there are special and continuously operating machines. Both horizontal and vertical types have one or more rams depending on production requirement. Dual ram models are arranged so that when one ram is on cutting stroke, the other is on return stroke, and return stroke is performed quickly to gain time. This time can be used to unload and load the machine.
Broaching machine usually pulls or pushes the broach through, or passes a work piece that is held in a fixture. On some machines, however, the work piece is moved past to broach which is fixed in its position. Most broaching machines are hydraulically operated to secure a uniform cutting action.