Spline Broaching VS. Rectangular Broaching : How To Choose?

How To Choose Between Spline Broaching Or Rectangular Broaching Processes To Meet Specific Workpiece Needs?

When choosing a spline broaching or rectangular broaching process to meet specific workpiece needs, there are several aspects to consider:

Workpiece Shape And Size

Shape requirements

  • If the workpiece requires a splined shape, spline broaching is the only option. Spline broaching can accurately process various types of splines, such as rectangular splines, involute splines, etc.
  • If the workpiece needs to be machined into rectangular shapes, such as rectangular holes, rectangular slots, etc., then rectangular broaching is a more suitable process.

Dimensions

  • For larger size workpieces, rectangular broaching may be more advantageous. Rectangular broaching can use larger size broaches and can process larger rectangular shapes.
  • For smaller size workpieces, both spline broaching and rectangular broaching can be considered. However, it is important to note that smaller sized spline broaches may be fragile and require more careful use and maintenance.

Processing Accuracy Requirements

High accuracy requirements

  • If the workpiece requires very high machining accuracy, such as dimensional tolerance within a few microns and very low surface roughness, then both spline broaching and rectangular broaching can meet the requirements. Both processes provide high-precision machining results.
  • In this case, a more suitable process can be selected based on the shape and size of the workpiece. If it is a spline shape, select spline broaching; if it is a rectangular shape, select rectangular broaching.

General accuracy requirements

  • If the workpiece does not require particularly high processing accuracy, the process can be selected based on factors such as cost and efficiency.
  • Generally speaking, the rectangular broaching process is relatively simple and low-cost, and is suitable for processing rectangular shapes with general accuracy requirements. The spline broaching process is relatively complex and costly, but it can provide higher precision and better surface quality, and is suitable for occasions that require high spline shape accuracy.

3.Production Batch

Mass production

  • If high-volume production is required, both spline broaching and rectangular broaching can be considered. Both processes have high production efficiency and can meet the needs of mass production.
  • When choosing, you can consider the stability and reliability of the process. Both spline broaching and rectangular broaching require the use of specialized broaching machines and broaching tools. The stability and reliability of these equipment have a great impact on production efficiency and product quality.
  • Additionally, tool life and replacement costs can be considered. For high-volume production, tool life and replacement costs are an important consideration.

Small batch production or single piece production

  • If you are producing small batches or single pieces, then rectangular broaching may be more advantageous. The rectangular broaching process is relatively simple, and the cost of equipment and tools is low, which can reduce production costs.
  • For spline broaching, since it requires special spline broaching tools and broaching machines, the cost is high and it is not suitable for small batch production or single-piece production.

4.Material properties

Material hardness

  • If the workpiece material is harder, both spline broaching and rectangular broaching require the use of a harder broach. In this case, the appropriate broach material and process parameters can be selected according to the hardness of the material and processing requirements.
  • Generally speaking, carbide broaches are suitable for processing materials with higher hardness, but the cost is also relatively high. High-speed steel broaches are suitable for processing materials with lower hardness and have lower costs

Material toughness

  • If the workpiece material has good toughness, problems such as deformation may occur during processing. In this case, appropriate process parameters and tool design can be considered to reduce deformation.
  • For spline broaching, smaller cutting depths and feeds can be used to reduce cutting forces and deformation. For rectangular broaching, appropriate tool geometry and cutting parameters can be used to improve cutting efficiency and reduce deformation

5.Costs and benefits

Equipment cost

  • Both spline broaching and rectangular broaching require the use of specialized broaching equipment. The price of broaching machines is relatively high, and the impact of equipment costs on production efficiency needs to be considered.
  • If the company already has broaching equipment, it can choose a suitable process based on the type and performance of the equipment. If the company does not have broaching equipment, it needs to consider the cost and feasibility of purchasing the equipment.

Tool cost

  • The prices of spline broaches and rectangular broaches are also relatively high. The impact of tool costs on production efficiency needs to be considered.
  • Generally speaking, the price of spline broach is higher than that of rectangular broach because the manufacturing process of spline broach is more complicated. However, if the workpiece needs to be machined into a spline shape, then a spline broach is essential.

Processing efficiency

  • Both spline broaching and rectangular broaching have high processing efficiency. However, the specific processing efficiency also depends on the shape, size, material and other factors of the workpiece.
  • When selecting a process, the impact of processing efficiency on production efficiency needs to be considered. If the production task is urgent, you need to choose a process with higher processing efficiency.

6.Technical Difficulty And Operator Skills

Technical difficulty

  • Both spline broaching and rectangular broaching require a certain level of skill and experience. The technical difficulty of spline broaching is relatively high and requires operators to have high skills and experience.
  • If the company does not have the relevant technology and experience, it may need to train or hire professionals. When choosing a process, you need to consider the technical level and experience of the company and choose a process with lower technical difficulty.

Operator skills

  • The skill level of the operator also affects the choice of process. If the operator has a higher skill level, a more technically difficult process can be selected. If the operator’s skill level is low, then a less technically difficult process needs to be selected.

In short, when choosing a spline broaching or rectangular broaching process to meet specific workpiece needs, factors such as workpiece shape and size, machining accuracy requirements, production batch size, material characteristics, cost and benefits, technical difficulty, and operator skills need to be comprehensively considered. . Only by choosing the most suitable process can the processing quality and production efficiency of the workpiece be guaranteed.

What Are The Key Points In The Design Of Spline Broach?

1.Determine spline parameters

  • First of all, it is necessary to clarify the type of spline to be processed (such as rectangular spline, involute spline, etc.), size (including module, number of teeth, pressure angle, etc.), accuracy requirements and other parameters. These parameters will directly affect the design of the broach.
  • For example, for rectangular splines, the key width, keyway depth, minor diameter and other dimensions need to be determined; for involute splines, the module, pressure angle, number of teeth, etc. need to be determined.

2.Tool material selection

  • Spline broaches are usually made of materials such as high-speed steel or carbide. High-speed steel has good toughness and machinability, and is suitable for spline processing with general precision requirements; carbide has higher hardness and wear resistance, and is suitable for processing materials with higher hardness or high-precision splines.
  • For example, when processing alloy steel splines with higher hardness, you can choose a carbide spline broach.

3.Blade tooth design

  • The teeth of spline broaches are divided into rough cutting teeth, fine cutting teeth and calibration teeth. Rough cutting teeth are mainly responsible for removing most of the allowance, and their tooth lift is large; fine cutting teeth further improve the processing accuracy, and their tooth lift is small; calibration teeth are used to ensure the dimensional accuracy and surface quality of the splines.
  • The shape and angle of the cutter teeth also need to be designed according to the type of spline and processing requirements. For example, the teeth of a rectangular spline broach are usually rectangular in shape, while the teeth of an involute spline broach are in an involute shape.

4.Chip flute design

  • The shape and size of the chip flute should ensure that chips can be discharged smoothly without affecting the strength and stiffness of the tool. Common chip flute shapes include linear, arc, etc.
  • The size of the chip flute should be calculated and determined based on factors such as the processing material and cutting parameters. For example, when machining ductile materials, the chip flutes should be relatively large to accommodate larger chips.

5.Strength and stiffness check of broaches

  • When designing a spline broach, the strength and stiffness of the broach need to be checked to ensure that the broach will not deform or break during the processing.
  • It can be checked by calculating the bending strength, torsional strength and other parameters of the broach and comparing them with the allowable stress.

What Are The Key Points In The Design Of Rectangular Broach?

1.Clarify Processing Requirements

  • Determine the dimensions (length, width, depth, etc.), accuracy requirements, surface roughness requirements, etc. of the rectangle. These parameters will determine the broach design.
  • For example, for high-precision rectangular hole processing, it is necessary to design a broach with higher precision.

2.Tool Material Selection

  • Similar to spline broaches, rectangular broaches can also be made of materials such as high-speed steel or carbide. When selecting materials, factors such as the hardness of the material to be processed and the processing batch size should be considered.
  • If the hardness of the processed material is high or the batch size is large, you can choose a carbide rectangular broach to improve the wear resistance and life of the tool.

3.Blade Tooth Design

  • The teeth of rectangular broaches are generally divided into rough cutting teeth, fine cutting teeth and calibration teeth. Rough cutting teeth remove most of the margin, fine cutting teeth improve accuracy, and calibrated teeth ensure size and surface quality.
  • The shape of the cutter teeth is usually rectangular, and its size and angle should be designed according to the processing requirements. For example, the width of the cutter teeth should match the width of the rectangle, and the height of the cutter teeth should be determined according to the processing depth.

4.Chip Flute Design

  • The chip flute design of the rectangular broach should consider the shape and discharge of the chips. Generally speaking, the shape of the chip flute can be linear, spiral, etc.
  • The size of the chip flute must be calculated and determined based on the processing material, cutting parameters and other factors to ensure that the chips can be discharged smoothly without affecting the strength of the tool.

5.Broach Guide Design

  • In order to ensure the stability and accuracy of the rectangular broach during processing, a reasonably designed guide device is required. The guide device can take the form of guide sleeves, guide posts, etc.
  • The size and accuracy of the guide device must match the broach to ensure that the broach can accurately cut along the predetermined trajectory during the machining process.

6.Strength And Stiffness Check

  • The strength and stiffness of rectangular broaches must also be checked during the design process to ensure that the tool will not deform or break during processing.
  • It can be checked by calculating the bending strength, torsional strength and other parameters of the broach and comparing them with the allowable stress. At the same time, finite element analysis and other methods can also be used to simulate and analyze the strength and stiffness of the broach to optimize the design plan.

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