Internal broaching machines and external broaching machines are the two main types of broaching machines. They differ in application fields, structural features, processing accuracy and efficiency. Understanding these differences can help you choose the right type of broaching machine for your specific machining needs.
Differences In Working Principles
Internal Broaching Machine
The internal broaching machine passes the broach through the inner hole of the workpiece under the action of tension. The cutting teeth cut off the metal in sequence, gradually enlarging the size of the inner hole and obtaining a high-precision inner surface.
External Broaching Machine
The broach of the external broaching machine makes circular or linear motion around the outer surface of the workpiece, and the cutting teeth remove the metal on the outer surface of the workpiece to achieve processing of the outer surface.
Differences Of Processing Objects
Internal Broaching Machine
The Internal Broaching Machine mainly used for processing internal shapes such as inner holes, spline holes, keyways, etc. of workpieces. For example, various inner holes of automobile engine blocks, cooling channels of molds, etc.
External Broaching Machine
The External Broaching Machine mainly used for Process the outer surface of the workpiece, such as plane, outer cylindrical surface, gear tooth profile and other external shapes. It is commonly used in the outer surface processing of large mechanical parts, such as ship propeller shafts, wind turbine main shafts, etc.
Different Of Structural Composition
Internal Broaching Machine
Main components: The bed provides stable support; the broach system includes a long rod-shaped broach, a broach chuck and a guide device to ensure the accuracy of the broach when processing the inner hole; the workbench is used to fix the workpiece.
Auxiliary devices: The cooling system usually uses coolant spray or cooling oil circulation to reduce the temperature of the inner hole processing; the chip removal system needs to effectively discharge the chips generated by the inner hole processing.
External Broaching Machine
Main components: The bed provides basic support for the external broaching machine. The broaching tool of the broaching system is generally flat or disc-shaped and is used to process the outer surface; the workbench and fixtures must firmly fix workpieces of different shapes; the transmission device drives the broaching tool Movement for external surface machining.
Auxiliary system: The cooling and lubrication system ensures the cooling and lubrication effects during outer surface processing; the chip removal system promptly handles the large amount of chips generated by outer surface processing
Comparison Of Processing Characteristics
Internal Broaching Machine
Processing accuracy: The inner hole processing space is relatively small, and the broach requires high dimensional accuracy. It can obtain an inner hole with high dimensional accuracy, shape accuracy and low surface roughness.
Production efficiency: Broaching can complete multiple machining processes of the inner hole at one time, which is highly efficient. However, due to the size of the inner hole, the efficiency may be limited when processing large inner holes.
Adaptation range: It is suitable for processing various internal hole shapes and workpieces of different materials, but for some special-shaped internal holes, a customized broach may be required.
External Broaching Machine
Processing accuracy: The shape accuracy of the external broach determines the external surface processing accuracy. High-precision external surface processing accuracy can also be achieved through high-precision tools and stable movement.
Production efficiency: For the outer surface processing of large workpieces, larger-sized broaches and efficient transmission devices can be used to achieve rapid processing, but for complex-shaped outer surfaces, more adjustment time may be required
Adaptation range: It can process the outer surface of workpieces of a variety of materials, and has certain advantages for large, complex-shaped workpieces. However, for small, high-precision outer surface processing, more sophisticated equipment may be required.
The Difference Between Operation And Maintenance
Internal Broaching Machine
Operation process: The workpiece installation needs to ensure the alignment accuracy of the inner hole and the broach; the broach selection should be based on the size and shape of the inner hole; the inner hole material and accuracy requirements must be considered when setting processing parameters. During the processing process, pay close attention to the processing status of the inner hole.
Maintenance: Routine maintenance includes cleaning chips generated by inner hole processing, lubricating the broach system, etc.; regular maintenance requires checking the wear of the broach and calibrating the accuracy of the equipment.
External Broaching Machine
Operation process: The preparation and installation of the workpiece must ensure that the relative position of the outer surface and the broach is accurate; the broach selection is based on the shape and size of the outer surface; the setting of processing parameters must take into account the workpiece material and outer surface processing requirements. Monitor the processing status of the outer surface during processing.
Maintenance: Routine maintenance includes cleaning chips from external surface processing, lubrication of broaches and transmission devices; regular maintenance includes replacing worn broaches and checking the operational stability of the equipment.
Focus On Application Fields
Internal Broaching Machine
Automobile manufacturing: used for processing key components such as engine blocks and transmission gear inner holes.
Aerospace: Processing of high-precision internal bore parts such as cooling holes for aero-engine turbine disks.
Mold manufacturing: Processing the inner hole of the mold, such as the cooling channel of the injection mold, etc.
External Broaching Machine
Large machinery manufacturing: processing the outer surface of large parts such as ship propeller shafts and wind turbine main shafts.
Construction machinery and mining machinery: processing the connecting surfaces of large structural parts, the outer cylindrical surfaces of shaft parts, etc
Aerospace: Processing of parts with high external surface precision requirements such as aircraft engine blades.
How to choose Internal Broaching Machine or External Broaching Machine ?
When choosing an internal or external broaching machine, you need to consider the following factors:
Processing requirements
- Determine whether the inner hole or the outer surface of the workpiece needs to be machined. If it is an inner hole, such as the shape, size, accuracy requirements of the inner hole, etc., then an internal broaching machine may be a more suitable choice; if it is an external surface, such as a flat surface, an outer cylindrical surface, a gear tooth profile, etc., external broaching should be considered. bed.
- Considering the material of the workpiece, different broaching machines may work better on certain materials.
Processing accuracy requirements
- Compare the capabilities of internal and external broaching machines in terms of machining accuracy. Generally speaking, both can provide higher accuracy, but the specific accuracy level will also be affected by factors such as machine tool model and tool quality.
- If there are very strict requirements for machining accuracy, the technical parameters and performance indicators of the machine tool need to be carefully studied.
Production efficiency
- Consider the batch size and production cycle of the workpieces. Internal broaching machines are usually more efficient when processing inner holes, and can complete multiple processes in one broaching; external broaching machines may have more advantages for processing the outer surface of large workpieces.
- Based on production needs, select machine tools that can meet production efficiency requirements.
Machine specifications and dimensions
- Make sure the machine tool is sized and sized to accommodate the size and shape of the workpiece. If the workpiece is large, you may need to choose a large external broaching machine; if the inner hole of the workpiece is small in size and complex in shape, you may need an internal broaching machine with higher precision.
- Consider the installation space and site requirements of the machine tool.
Budget
- The prices of internal and external broaching machines of different models and configurations may vary greatly. Choose the right machine tool based on your budget, while ensuring that your processing needs can be met within your budget.
Brand and after-sales service
- Choosing machine tools from well-known brands usually guarantees better quality and performance.
- Understand the quality of the manufacturer’s after-sales service, including repairs, maintenance, technical support, etc., to ensure that the machine tool can receive timely maintenance and support during use.
Conclusion
To sum up, choosing between internal broaching machine or external broaching machine requires comprehensive consideration of factors such as processing needs, accuracy requirements, production efficiency, machine tool specifications, budget, brand and after-sales service. Before making a decision, it is recommended to fully communicate with the machine tool manufacturer or supplier to understand their suggestions and recommendations, and if possible, conduct on-site inspections or trial processing to ensure that you choose the machine tool that best suits your needs.