Rectangular Broaching: The Complete Guide

What is Rectangular Broaching?

Rectangular broaching utilizes the broach’s multiple cutting teeth to sequentially remove metal from a workpiece to create the desired rectangular shape. Under the action of tension, the broach moves along the axial direction of the workpiece, and the height of each cutting tooth gradually increases to achieve progressive cutting.

What is Rectangular Broaching?

Advantages Of Rectangular Broaching

High processing efficiency: Rectangular broaching can remove a large amount of material in one stroke, which greatly improves production efficiency and is especially suitable for mass production.

High processing accuracy: high dimensional accuracy and shape accuracy can be obtained. The rectangular surface roughness after broaching is low, and the dimensional tolerance can be controlled within a small range.

Suitable for a variety of materials: can process various metal materials, such as steel, cast iron, non-ferrous metals, etc.

Long tool life: Rectangular broaches are usually made of high-strength materials and have good wear resistance. With reasonable use and maintenance, the tool life is long.

Disadvantages Of Rectangular Broaching

High cost of broaches: The manufacturing process of rectangular broaches is complex and requires high-precision processing equipment and technology, so the manufacturing cost of broaches is high.

High equipment requirements: Special broaching equipment is required. The broaching machine is expensive and covers a large area. It also requires high accuracy, rigidity and stability of the machine tool.

Poor flexibility: The rectangular broach is a special tool that can only process rectangles of specific sizes and shapes. For workpieces with complex shapes or large changes in size, different broaches need to be replaced, resulting in poor flexibility.

Structure Of Rectangular Broach

Structure Of Rectangular Broach

The rectangular broach mainly consists of the following parts:

  • Handle: used to connect the broach and broaching machine to transmit pulling force.
  • Neck: Located between the handle and the transition cone, its main function is to clamp and transport the broach during the manufacturing process.
  • Transition cone: enables the broach to smoothly enter the pre-made hole in the workpiece.
  • Leading part: guides the broach to enter the workpiece correctly and prevents the broach from deflecting when entering the workpiece.
  • Cutting part: It consists of several cutter teeth and is the main working part of the broach, used to cut off the allowance on the workpiece.
  • Calibration Department: Perform final calibration and trimming of workpieces to ensure processing size and shape accuracy.
  • Rear guide part: guides the broach to withdraw from the workpiece correctly and prevents the broach from deflecting when withdrawing from the workpiece.

Process Of Rectangular Broaching

The steps for rectangular broaching are as follows:

1.Preparation stage

  • Design Planning
    • According to the requirements of the workpiece, parameters such as size, accuracy and surface quality of rectangular broaching are determined. Design the shape, size and tooth profile of the broach to meet processing needs.
    • Consider factors such as workpiece material, hardness, shape and size to select the appropriate broach material and manufacturing process.
  • Artifact Preparation:
    • Preprocess the workpiece, such as drilling, boring, etc., to process a prefabricated hole similar to the shape of the broach. The size and accuracy of the prefabricated hole should meet the requirements of broaching to ensure that the broach can enter the workpiece smoothly.
    • Clean oil, rust and other impurities on the surface of the workpiece to ensure cutting performance and surface quality during broaching.
  • Broach selection:
    • Select the appropriate rectangular broach according to the size, accuracy and material requirements of the workpiece. The size of the broach should match the pre-made hole of the workpiece to ensure stability and accuracy during the broaching process.
    • Check the quality and accuracy of the broaches to ensure that the teeth are sharp and free of wear and defects. If necessary, broaches can be sharpened and adjusted to improve broaching performance.

2.Installation and debugging stage

  • Broaching preparation:
    • Check the performance and accuracy of the broaching machine and ensure that components such as the table, guide rails and clamps of the broaching machine are in good condition. Adjust broaching machine parameters such as broaching speed, feed and depth of cut to suit different workpieces and broaches.
    • Install the broach fixture and guide device to ensure the stability and accuracy of the broach during the broaching process.
  • Artifact installation:
    • Mount the workpiece on the table of the broaching machine, positioning and clamping it using suitable clamps. Ensure that the workpiece does not move or deform during the broaching process to ensure processing accuracy and surface quality.
    • Adjust the position and angle of the workpiece so that the broach can smoothly enter the pre-made hole of the workpiece and remain perpendicular to the machined surface of the workpiece.
  • Broach installation:
    • Install the broach on the clamp of the broaching machine, making sure that the handle of the broach fits tightly with the clamp and will not loosen or shift. Adjust the position and angle of the broach so that the teeth of the broach remain parallel to the machined surface of the workpiece.
    • Install the guide device of the broach, such as guide sleeves, guide posts, etc., to ensure the stability and accuracy of the broach during the broaching process. The size and accuracy of the guide device should match the broaching tool to ensure smooth progress during the broaching process.

3.Broaching stage

  • Start broaching machine:
    • Start the broaching machine so that the broach gradually enters the prefabricated hole of the workpiece under the action of pulling force. During the broaching process, pay attention to the cutting conditions of the broach and the machined surface quality of the workpiece. If there are any abnormalities, stop the machine for inspection in time.
    • Control the broaching speed and feed, and select the appropriate broaching speed and feed based on factors such as the material, hardness, and size of the workpiece. Broaching speed that is too fast will lead to increased wear of the broach and a decrease in the quality of the machined surface; broaching speed that is too slow will affect production efficiency. Excessive feed rate will also lead to increased broach wear and reduced processing surface quality; too small feed rate will affect production efficiency.
  • Cutting process
    • The teeth of the broach gradually remove the excess on the workpiece during the broaching process, forming a rectangular hole or groove. During the cutting process, attention should be paid to controlling the cutting force and cutting temperature to avoid overheating of the broach and increased wear. The cutting temperature can be reduced by using cutting fluid and the wear of the broach can be reduced.
    • Observe the cutting conditions of the broach and the machined surface quality of the workpiece. If there are any abnormalities, stop the machine for inspection in time. If problems such as serious wear of the broach, excessive cutting force, or reduced quality of the machined surface are found, the broaching parameters should be adjusted in time or the broach should be replaced.
  • Complete broaching
    • The broaching process ends when the broach has completely passed through the workpiece. Close the broaching machine, take out the workpiece and broach, clean and inspect.

4.Follow-up processing stage

  • Cleanup check
    • Clean the chips and oil stains on the workpiece and broach, and check whether the processing size, accuracy and surface quality of the workpiece meet the requirements. If necessary, subsequent finishing or processing, such as grinding, honing, etc., can be performed to improve processing accuracy and surface quality.
    • Check the broach for wear and sharpen or replace it if necessary.
  • Quality control
    • Conduct quality inspections on processed workpieces, such as dimensional measurement, surface roughness testing, hardness testing, etc., to ensure that the quality of the workpieces meets requirements. If there are unqualified workpieces, they should be reworked or scrapped in time.
    • Record parameters and quality data during processing for quality analysis and improvement.

The above are the general steps for rectangular broaching. The specific operation process may vary depending on factors such as the requirements of the workpiece, the type of broaching machine, and the characteristics of the broaching tool. When performing rectangular broaching, the operating procedures should be strictly followed to ensure processing quality and safety.

What Are The Common Problems And Solutions For Rectangular Broaching?

Broaching Rough Surface

  • Reasons: broach wear, unreasonable cutting parameters, poor cooling and lubrication, excessive hardness of workpiece material, etc.
  • Solution: promptly replace worn broaches, adjust cutting parameters, improve cooling and lubrication conditions, pretreat workpieces to reduce hardness, etc.

Dimensional Deviation

  • Reasons: Inaccurate broach size, inaccurate workpiece installation, uneven broaching force, etc.
  • Solution: Check and correct the size of the broach, ensure the correct installation of the workpiece, optimize the broaching process to evenly distribute the broaching force, etc.

Broach Breaks

  • Reasons: excessive broaching force, defective broach, improper operation, etc.
  • Solution: Adjust cutting parameters to reduce broaching force, check broach quality, standardize operations to avoid collision between broach and workpiece, etc.

Rectangular Shape Error

  • Reasons: The tooth shape of the broach is inaccurate, the workpiece is deformed during the broaching process, the broaching accuracy is insufficient, etc.
  • Solution: Check and correct broach tooth profile, control cutting force and clamping force to reduce workpiece deformation, maintain broaching accuracy, etc.

Applications Of Rectangular Broaching Process

The rectangular broaching process has the following wide applications in actual production:

1.Machinery manufacturing field

  • Gearbox processing
    • In the production of gear boxes, rectangular broaching is often used to process various mounting holes and positioning holes on the box body. The dimensional accuracy and positional accuracy of these holes require high requirements. Rectangular broaching can ensure the regular shape and accurate size of the holes, providing a reliable foundation for the installation and operation of gears.
    • For example, the bearing mounting hole on the automobile gearbox case can be obtained by rectangular broaching to obtain a high-precision rectangular shape, ensuring a tight fit between the bearing and the case, reducing vibration and noise, and improving the performance and life of the gearbox.
  • Engine block processing
    • The engine block is a key component of the automobile engine. Many of the oil passage holes, water passage holes and mounting holes on it are processed by rectangular broaching technology. Rectangular broaching can process multiple holes in one broaching process, improving production efficiency while ensuring the dimensional accuracy and surface quality of the holes.
    • For example, rectangular broaching can be used to process the piston cooling oil passage hole on the engine block to produce a precise rectangular cross-section, ensuring stable flow and pressure of the cooling oil and improving the heat dissipation performance of the engine
  • Machine tool parts processing
    • Rectangular holes and slots on machine tool worktables, columns, guide rails and other parts are usually processed by rectangular broaching. These holes and slots require high precision, which directly affects the processing accuracy and performance of the machine tool.
    • For example, the T-shaped slot on the machine tool table can be machined into a standard rectangular shape through rectangular broaching, providing a reliable basis for clamping and positioning the workpiece.

2.Aerospace field

  • Processing of aircraft structural parts
    • In aircraft manufacturing, rectangular broaching is used to process various connection holes and mounting holes on aircraft fuselages, wings and other structural parts. The accuracy of these holes is extremely high, and rectangular broaching can ensure the dimensional accuracy and positional accuracy of the holes, ensuring the safety and reliability of the aircraft structure.
    • For example, for the flap connection holes on the aircraft wings, rectangular broaching can be used to process high-precision rectangular holes to ensure that the flaps and wings are firmly connected and can withstand huge aerodynamic loads during flight.
  • Engine parts processing
    • Some rectangular holes and slots on key components such as turbine disks and blades of aeroengines are also processed using rectangular broaching processes. These parts work in harsh environments and require extremely high precision and quality. Rectangular broaching can meet their processing requirements.
    • For example, rectangular broaching can be used to process the cooling air passage holes on the turbine disk to produce a precise rectangular cross-section, ensuring stable cooling air flow and pressure, and improving the working efficiency and lifespan of the turbine disk.

3.Mold manufacturing field

  • Injection mold processing
    • Injection molds are key equipment for the production of plastic products. Many of the cooling water channel holes, ejector holes, and slider grooves on them are processed using rectangular broaching processes. Rectangular broaching can process high-precision rectangular shapes to ensure the cooling effect and demoulding performance of the mold.
    • For example, the cooling water channel hole on the injection mold can be processed into a regular rectangular cross-section through rectangular broaching, which improves the cooling efficiency and shortens the molding cycle of plastic products.
  • Stamping mold processing
    • Various guide column holes, guide bushing holes and discharge plate grooves on stamping dies are also often processed by rectangular broaching. These holes and grooves require high precision, which directly affects the quality of stamping parts and the service life of the mold.
    • For example, rectangular broaching can be used to process the guide pin hole on the stamping mold to produce a high-precision rectangular shape, ensuring the guiding accuracy of the mold and improving the dimensional accuracy and surface quality of the stamping parts.

4.Electronic equipment manufacturing field

  • Chassis shell processing:
    • Many of the various mounting holes and heat dissipation holes on the chassis of electronic equipment are processed by rectangular broaching. Rectangular broaching can produce a precise rectangular shape, ensuring the assembly accuracy and heat dissipation performance of the chassis.
    • For example, for the motherboard mounting holes on the computer chassis, rectangular broaching can be used to process standard rectangular holes to ensure a firm connection between the motherboard and the chassis and to facilitate the installation and ventilation of the cooling fan.
  • Connector processing:
    • For various connectors in electronic equipment, such as rectangular connectors, USB connectors, etc., the rectangular holes and slots on the shells are often processed by rectangular broaching. These holes and slots require high precision, which directly affects the plugging and unplugging performance and signal transmission quality of the connector.
    • For example, for the pin holes on rectangular connectors, rectangular broaching can be used to process a high-precision rectangular cross-section, ensuring a tight fit between the pins and the socket, and improving the stability and reliability of signal transmission.

Conclusion

The rectangular broaching process has unique advantages and can meet the processing needs of complex workpieces. Selecting an appropriate rectangular broach, such as a carbide broach based on materials with high hardness, can improve the processing effect. If you want to learn more, please feel free to contact us.

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