Broaching: A Precision Machining Process with Diverse Applications

Broaching is a precision machining process that has been a cornerstone of manufacturing for decades. It involves removing material from a workpiece by using a specialized cutting tool called a broach. This tool, with its unique design, creates various shapes, profiles, and surface finishes on a wide range of materials, making broaching a versatile and indispensable technique in the world of manufacturing.


How Broaching is done: Broaching is a complex process that requires precision and expertise. Here's an overview of how broaching is done:

  1. Selection of the Broach:
    The first step is to choose the right broach for the job. Broaches come in various types, including keyway broaches, spline broaches, internal and external broaches, and surface broaches. The choice depends on the specific requirements of the workpiece.

  2. Fixturing:
    The workpiece is securely mounted in a fixture to prevent movement during the broaching process. This is crucial to ensure accuracy and consistency.

  3. Broach Setup:
    The broach tool is set up in a broaching machine. There are two primary types of broaching machines: vertical and horizontal. The choice depends on the geometry and size of the workpiece.

  4. Feeding and Cutting:
    During the broaching process, the broach is fed into the workpiece. The cutting edges of the broach gradually remove material as it advances. This is done in a single pass, and the rate of feed and speed of cutting are carefully controlled to achieve the desired results.

  5. Pull or Push Broaching:
    Broaching can be done by either pulling the broach through the workpiece (pull broaching) or pushing it (push broaching). Pull broaching is more common, as it typically generates better results with less stress on the machine.

  6. Coolant and Lubrication:
    To reduce heat and friction, coolant and lubrication are often used during the broaching process. This not only extends the life of the broach but also enhances the quality of the finished workpiece.

  7. Removal of Material:
    As the broach progresses through the workpiece, it removes material in a controlled manner. The design of the broach dictates the shape and dimensions of the cut, allowing for precision and repeatability.

  8. Finishing Pass:
    After the rough broaching pass, a finishing pass may be necessary to achieve the required surface finish and tight tolerances. This pass can be done using a separate broach or by adjusting the existing broach's settings.


Applications of Broaching: Broaching is used in various industries for a wide range of applications, thanks to its ability to produce intricate and precise features. Here are some common applications of broaching:

  1. Keyways and Splines:
    Broaching is frequently used to create keyways and splines in shafts, gears, and other components. These are essential in machinery to transmit torque and ensure proper alignment.

  2. Internal Shapes:
    Broaching is employed to create internal shapes in components, such as square or hexagonal holes in nuts and bolt heads.

  3. Surface Broaching:
    This process can be used to produce a specific surface finish or texture on parts, which is common in the automotive and aerospace industries.

  4. Turbine Blades:
    The aerospace industry often uses broaching for machining turbine blades. This requires extreme precision to ensure optimal aerodynamics and performance.

  5. Firearms Manufacturing:
    Broaching is integral to producing gun barrels, chambers, and other firearm components with high precision and accuracy.

  6. Medical Devices:
    In the medical industry, broaching is used for producing components like orthopaedic implants, surgical instruments, and dental tools.

  7. Automotive Components:
    Broaching is employed in the automotive sector for creating various components, including axles, transmission gears, and steering components.

  8. Hydraulic Cylinders:
    Broaching is crucial in manufacturing hydraulic cylinders for creating the internal grooves and contours necessary for sealing and fluid movement.


Broaching is a versatile machining process that is vital to various industries. Its ability to produce precise and intricate features on a wide range of materials makes it indispensable in the manufacturing world. Whether it's shaping keyways in gears or producing complex internal profiles in medical devices, broaching plays a critical role in meeting the demands of modern engineering and design.


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