Essential Tips: How To Avoid Broach Breakage?

Explore key strategies for ensuring broach tool longevity and minimizing breakage. This guide emphasizes the importance of proper tool storage, routine inspections, and corrective actions to maintain tool integrity.

What Is Broach Breakage Reason？

The reasons for broach damage mainly include the following aspects:

Broach’S Own Factors

1. Broach material is inappropriate
   • The selected broach material’s hardness, toughness and other properties cannot meet the requirements of the processed material.
   • For example, when machining high-hardness materials, a broach material with insufficient hardness is used.
2. Broach manufacturing defects
   • During the manufacturing process of broaches, there are problems such as uneven edge grinding and inaccurate tooth geometry.
   • For example, the tooth pitch deviation of the broach is too large, resulting in uneven distribution of cutting force.
3. Excessive broach wear
   • If it is not sharpened in time after long-term use, the blade wears seriously and the cutting ability decreases.

Processing Technology Factors

1. Broaching allowance is too large
   • The single broaching allowance exceeds the bearing capacity of the broach, making the broach overloaded.
   • For example, an excessively large broaching allowance may be set incorrectly without sufficient evaluation.
2. Improper broaching speed and feed
   • If the speed is too fast or the feed amount is too large, the cutting force will increase sharply and the broach will be easily damaged.
   • For example, higher broaching speeds and feeds are still used when machining harder materials.
3. Insufficient cooling and lubrication
   • There is a lack of effective cooling and lubrication during the cutting process, and the broach generates excessive heat, resulting in increased wear and even damage.
   • For example, the supply of cutting fluid is poor or the type of cutting fluid selected is inappropriate.

Equipment Factors

1. Broaching accuracy decreases
   • The guide rails, screws and other parts of the broaching machine are worn, resulting in unstable movement during the broaching process and uneven force on the broach.
   • For example, after long-term use of a broaching machine, obvious wear and gaps appear on the guide rails.
2. Insufficient pulling force of broaching machine
   • Insufficient pulling force is not provided to complete the broaching process, placing the broach under additional stress during the cutting process.

Workpiece Factors

1. Workpiece material is uneven
   • There are hard points, inclusions or uneven materials inside, causing excessive local cutting resistance.
   • For example, there are defects such as blisters and pores in casting workpieces.
2. Improper workpiece clamping
   • Insecure clamping causes the workpiece to move or vibrate during the broaching process, affecting the normal cutting of the broach.

Operation Factors

1. operator error
   • Violation of operating procedures, such as forced broaching, incorrect installation of broaches, etc.
2. Lack of experience and skills
   • The process parameters cannot be adjusted in time according to the actual situation or abnormal situations are discovered.

To sum up, broach breakage is usually caused by a combination of factors such as the broach itself, processing technology, equipment, workpieces, and operations. Through in-depth analysis and effective control of these factors, the occurrence of broach breakage can be reduced.

How Do I Determine If I Can Mend a Broken Broach?

To determine whether a broach breakage is repairable, the following aspects need to be considered:

1.Degree Of Breakage

• Observe the extent and size of the breakage. If there is only a slight wear of the edge, a small chip or a small amount of chipping, it is usually repairable. However, if the broach has a large area of breakage, severe twisting or deformation, repair is less likely.
• For example, edge wear of only a few millimeters can usually be repaired by sharpening; whereas a break in the broach body of more than half its length may be difficult to repair.

2.Location Of Breakage

• Breakage occurs in the key parts of the broach, such as cutting edge, chip groove, etc., repair is more difficult. If the damage occurs in non-critical areas, such as the shank, toolholder, etc., the feasibility of repair is relatively high.
• For example, serious damage to the cutting edge may affect the broaching accuracy and effect, and it is difficult to guarantee the quality after repair; while minor damage at the shank is usually easier to deal with.

3. Broach Material

• Understand the material characteristics of broaches. For some high hardness, high strength and difficult to process the material, the repair is more difficult; while the common material broach may be easier to repair.
• For example, carbide broaches require a high level of repair work after breakage, while ordinary high-speed steel broaches are relatively easy to repair.

4. Economic Feasibility

• Evaluate the cost of repairing a broach versus the cost of purchasing a new broach. If the repair cost is too high, close to or exceeding the price of a new broach, and the quality and service life of the repair is difficult to guarantee, it may not be worth repairing.
• For example, if the repair requires special equipment and processes that are costly, and the price of a new broach is relatively low, it may be more cost-effective to replace the broach with a new one.

5. Technical Feasibility

• Consider whether the appropriate restoration techniques and equipment are available. Without mature repair techniques and specialized equipment, it is difficult to perform effective repair even if the degree of damage is small.
• For example, certain complex breakages require high-precision processing equipment and specialized welding techniques, which cannot be repaired without these conditions.

Combining the above factors, you can more accurately determine whether the broach breakage can be repaired, so as to make a reasonable decision.

How To Repair A Broken Broach?

After the broach is damaged, an appropriate repair method needs to be selected based on the degree and cause of the damage. Here are some common broach repair methods:

1. Sharpening: A worn blade can be sharpened to restore its sharpness. When sharpening, care must be taken to maintain the proper angle and amount of grinding to avoid excessive wear or damage to the blade.

2.Repair welding: If the broach cracks or breaks, repair welding can be used to repair it. Appropriate welding materials and processes need to be selected during repair welding to ensure welding strength and quality.

3.Adjustment: For some broach breakage caused by improper installation or use, it can be solved by adjusting the installation position and cutting parameters of the broach.

4.Replace parts: If some parts of the broach are seriously damaged and cannot be repaired, the corresponding parts need to be replaced.

5.Professional repair: For some complex broach breakage problems, professional repair tools and techniques may be required. You can contact a professional broach repair manufacturer or maintenance personnel for repair.

It should be noted that when repairing a broach, it is necessary to select the appropriate repair method according to the specific situation and strictly follow the repair process and operating procedures to ensure the repair quality and service life. At the same time, in order to avoid the occurrence of breakage of the broach, you need to pay attention to the correct installation, use and maintenance methods when using the broach.

How To Determine The Specific Location And Extent Of Broach Damage?

To determine the specific location and extent of broach damage, the following methods can be used:

visual Inspection

• Directly observe the overall appearance of the broach with the naked eye, including the blade, teeth, shank and other parts. Pay attention to look for obvious signs of damage, cracks, deformation, chipping, wear, etc.
• For example, a chip in the blade, a broken tooth, or a bend in the shank may be apparent.

Use A Magnifying Glass Or Microscope

• For minor damage, such as tiny cracks, minor wear on the cutting edge, etc., use a magnifying glass or microscope to observe carefully.
• For example, tiny chips or wear marks on the cutting edge can be clearly seen under a microscope.

Measuring Tool Inspection

• Use measuring tools such as calipers and micrometers to measure the key dimensions of the broach, such as the width of the blade, the height of the teeth, the diameter of the tool bar, etc., and compare them with the standard dimensions to determine whether there are dimensional changes and wear.
• For example, measuring the decrease in blade width can reflect the extent of wear.

Magnetic Flaw Detection

• For cracks and other imperceptible damages that may exist inside the broach, magnetic flaw detection can be used. Determine whether there are internal cracks by applying a magnetic field to the surface of the broach and observing the distribution of magnetic particles.
• For example, if there are internal cracks, magnetic particles will gather at the cracks and show up.

Cutting Test

• Observe the cutting effect of the broach during the actual cutting process. If the machined surface quality is poor, the size deviation is large, the cutting force is abnormal, etc., it may indicate that the broach is damaged.
• For example, if the surface roughness after processing increases significantly, it may be caused by the breakage of the broach blade.

Comparative Analysis

• Compare a damaged broach with an unused or intact broach of the same model to more intuitively discover the difference in location and degree of damage.

Through the comprehensive application of the above methods, the specific location and degree of broach damage can be determined more accurately, providing a basis for subsequent repair or replacement decisions.

6 Steps Avoid Broach Breakage

Here are some ways to avoid broach breakage:

1. Correctly Choose The Broach

• According to the hardness, strength, toughness and other characteristics of the processed material, the broach of appropriate material and geometry is selected.
  • For example, for materials with higher hardness, a broach with higher hardness and better wear resistance should be selected, such as a carbide broach.
• Ensure that the size and accuracy of the broach meet the processing requirements to avoid uneven stress on the broach due to size mismatch or insufficient accuracy.

2. Reasonably Arrange The Broaching Process

• Determine the appropriate broaching allowance to avoid excessive allowance that increases the load on the broaching tool.
  • Conduct sufficient process analysis to accurately calculate the broaching allowance, such as estimating the allowance through measurement before processing.
• Select the appropriate broaching speed and feed, taking into account material properties and broach durability.
  • For harder materials, reduce broaching speed and feed to prevent excessive wear of the broach.

3. Optimize Cooling And Lubrication During Broaching

• Use appropriate cutting fluid to ensure good cooling and lubrication effects.
  • For example, when machining high-hardness materials, use cutting fluids containing extreme pressure additives.
• Ensure adequate supply and correct injection direction of cutting fluid so that it can effectively cool and lubricate the contact area between the broach and the workpiece.

4. Keep The Broaching Machine In Good Condition

• Regularly inspect and maintain the broaching machine to ensure its accuracy and stable performance.
  • For example, check the wear of moving parts such as guide rails and screws of the broaching machine, and replace worn parts in time.
• Adjust various parameters of the broaching machine, such as pulling force, stroke, etc., to match the broaching tool and processing technology.

5. Correctly Clamp The Workpiece And Broach

• The workpiece should be clamped firmly to ensure that it does not move or vibrate during the broaching process.
  • Use appropriate clamps and ensure that the clamp’s clamping force is evenly distributed.
• The broach should be installed accurately to ensure that it is consistent with the movement direction of the broaching machine and that it is installed firmly without looseness.

6. Operator Training

• Provide professional training to operators to familiarize them with the broaching process and equipment operation.
  • Regularly organize training courses to update the knowledge and skills of operators.
• Cultivate the operator’s sense of responsibility and attentiveness, and strictly follow the operating procedures.

Through the above various measures, we can effectively avoid broach breakage, extend the service life of the broach, and improve the quality and efficiency of broaching.

How To Choose The Right Broach For A Specific Machining Task?

Selecting a broach suitable for a specific machining task requires considering the following key factors:

Characteristics Of Machined Parts

1. Shape and size: Select the corresponding shape and specification of the broach according to the shape (such as round hole, square hole, spline hole, etc.), diameter, depth and other geometric characteristics of the hole to be processed.
   • For example, processing large-diameter round holes requires a large round hole broach, while processing rectangular spline holes requires a specially designed spline broach.
2. Precision requirements: If the part requires high processing accuracy, such as a small tolerance range and low surface roughness, you need to choose a broach with high manufacturing precision, sharp edge and good grinding quality.
3. Material: Consider the material properties of the parts being processed, such as hardness, toughness, thermal conductivity, etc. For materials with high hardness, you need to choose a broach material with higher hardness and better wear resistance.

Read More: How To Broaches Design?

Processing Conditions

1. Broaching allowance: Determine a reasonable broaching allowance based on the size difference between the initial state of the part and the final required size. The size of the margin will affect the tooth lift and number of teeth design of the broach.
2. Broaching speed and feed: Select the appropriate broaching speed and feed according to the processing material, accuracy requirements and equipment performance. This will affect the stress and wear of the broach, thus affecting the choice of broach.
3. Cooling and lubrication: If good cooling and lubrication conditions can be provided during processing, you can choose a broach with higher cutting performance; otherwise, you need to choose a broach that is more wear-resistant and high-temperature resistant.

Production Volume And Economy

1. Mass production: For mass production, durable and efficient broaches should be selected, and special broaches may need to be customized to improve production efficiency and reduce costs.
2. Small batch production: In the small batch production or trial production stage, you can choose a standard broach with greater versatility and lower cost, or consider leasing a broach.
3. Cost consideration: Not only the purchase cost of the broach must be considered, but also its service life, maintenance costs and impact on production efficiency and other comprehensive costs.

Broach Material And Coating

1. Material: Common broach materials include high-speed steel, carbide, etc. High-speed steel has good toughness and is suitable for general processing; cemented carbide has higher hardness and wear resistance and is suitable for processing high-hardness materials.
2. Coating: Some broaches may have coatings, such as TiN, TiAlN, etc., which can improve the wear resistance, high temperature resistance and cutting performance of the tool.

Device Compatibility

Make sure that the selected broach matches the model and specifications of the broaching machine used and can be installed and operated correctly.

Suppliers And Brands

1. Choose a supplier or brand with good reputation, rich experience and technical strength. They can usually provide broach products with reliable quality and complete technical support, and can provide professional selection suggestions based on your needs.

Taking the above factors into consideration, the broach suitable for specific processing tasks can be selected more accurately to meet the requirements of processing quality, efficiency and cost.