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What is a Broach

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What is a broach?

The broach is a special tool that arranges the different functions and sizes of the cutter teeth in the order of rough cutting and finishing, and is mainly installed on the broaching machine.

What is a broach?

The broach is a multi-toothed tool with high productivity and high precision. It can broach the inner surface of various shapes (such as round holes, polygonal holes and various spline holes, etc.) and the outer surface direction (such as the groove of the root of the gas turbine blade, the external gear and the semicircular hole and the groove plane of the connecting rod, etc.)

The broach used to broach the internal surface is called inside broach, and the broach used to broach the external broach is called broach. The majority of the broaching forces are tensile forces, however some are compression forces. The broach under compression force is called broach, and the broach under thrust is called pushing broach. Considering the stability, pushing broach is relatively short.

The broach has many forms of movement during machining, some for linear motion, some for circular motion, some for broach movement, and some for workpiece movement, and some for both. In most cases, when the broach is working, the workpiece is fixed and the broach is used for linear cutting motion.

The feed motion of the broach is generally achieved by gradually increase the size of cutter tooth. For normal broach, the difference between the two consecutive cutter tooth or radius size is called rise per tooth, which is, generally, the broaching thickness. Generally, the rise per tooth of broach is small, only scores of micrometers.

The broach is a special tool and is expensive to manufacture, but it is economical to use in mass production. However, if the shape and size of the machine have been standardized, the broach can be mass produced by the tool factory. Good economic results can also be obtained in mass production. At present, most of the broaching broach with standard round holes and spline holes have been standardized.

The broaching speed of broach is generally slow, and 0.017-0.13m/s is commonly used. And the broaching thickness is very thin. Therefore, the surface finish is relatively high, normally, it can reach ▽5~▽7. The rate of wear of the cutter tooth is very slow, and the cutter tooth has very high durability and machining precision, which can reach 1T7~9 grade when broaching holes and even 1T6 and ▽8~▽9 grade if extrusion ring is equipped at the end of the broach. The production efficiency of the broach is very high, because the number of working teeth of the broaching process is large, and the roughing and finishing can be completed simultaneously in one working stroke.

Advantages of broaching

  • Short processing times and high efficiency.
  • High precision machining with small tolerances.
  • Good roughness of the machined surface (=125S)
  • If the axle of irregular shape and straightforward multi shapes are in the same axle, it can also be machined.
  • It will be just all right is the axle of irregular shape and straightforward multi shapes are in the same axle and direction.
  • The method of processing is simple, and the operator who is not skilled can also work.