Tool Wear And Chipping in The Machine Tool：What Is The Root Cause?

In machining processes, the efficiency of tool usage directly affects production stability and workpiece quality. As workers in a machining factory or workshop, we are all familiar with the fact that tool wear and chipping problems can not only cause production downtime but also lead to expensive repair and replacement costs.

We often encounter tool wear and chipping during production, which could be caused by improper cutting parameters, inappropriate tool materials, or poor machine tool conditions. Regardless of the reason, these issues impact production progress and increase costs.

So, what are the underlying causes of tool wear and chipping? How can we reduce these issues and extend tool life? This article will take you through the causes of tool wear and chipping step by step, providing practical and effective strategies to help improve production efficiency and reduce unnecessary losses

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Ⅰ. Symptoms of Tool Breakage

When a tool breaks, production is often forced to stop, and the workpiece may even be damaged. In practice, tools that break typically show some obvious symptoms. As operators, knowing these symptoms can help you detect problems immediately and avoid further losses.

· Abnormal Sounds: If you hear a “pop” or “crack” sound during machining, it is likely that the tool is being subjected to excessive cutting forces and is on the verge of breaking.

· Increased Cutting Force: Normally, the cutting force required by the tool should remain stable. If you suddenly feel an increase in cutting force, it could mean that a part of the tool is damaged or even close to breaking.

· Surface Wear or Cracks on the Tool: If you carefully inspect the cutting edge of the tool and find cracks, nicks, or other signs of wear, it is a strong indication that the tool is experiencing significant damage, and the machine should be stopped for inspection.

· Part Size Deviation: After tool breakage, the tool may no longer maintain machining accuracy, causing part dimensions to deviate. At this point, product quality may be compromised, and immediate action is needed.

· Chip Formation Changes: Tool breakage may also result in abnormal chip formation, such as chips being too small, fragmented, or no chips being produced at all—this is another indicator of tool failure.

Ⅱ. Causes of Tool Wear

Tool wear is an inevitable process, but its rate and extent often depend on various factors.

· Excessive Cutting Speed and Feed Rate: If the cutting speed and feed rate are set too high during machining, it can lead to excessive tool surface temperature, accelerating tool wear. Particularly when machining hard materials, excessive cutting speed can dull the tool, reducing machining efficiency.

· Improper Tool Selection: The material and geometry of the tool need to be selected according to the properties of the material being machined. If the wrong tool is chosen, it will not only accelerate wear but may also lead to machining inaccuracies.

· Tool Material Degradation: When tools are exposed to high temperatures or high-stress environments for extended periods, especially during high-speed machining, the material of the tool gradually degrades.Materials such as High-Speed Steel (HSS) and Carbide lose hardness and cutting performance over time.

· Insufficient Lubrication and Cooling: If the coolant flow is insufficient during cutting, friction between the tool and workpiece increases, raising the tool surface temperature and further accelerating wear. Therefore, adequate cooling and lubrication are critical to reducing wear.

· Improper Tool Alignment: If the tool is not properly aligned with the workpiece or there is an inherent misalignment in the machine tool, the forces on the tool during machining become uneven, leading to localized wear or even breakage.

To prevent rapid tool wear, we can reduce the wear rate by adjusting cutting parameters, regularly inspecting tool conditions, and selecting appropriate tool materials.

Ⅲ. How to Prevent Tool Breakage

Tool breakage is not only a sign of equipment failure but also a potential hazard in production. To avoid such situations, we can address this issue from several aspects to ensure tool stability and reliability.

· Optimize Cutting Parameters: Reasonably selecting cutting speed, feed rate, and depth of cut can effectively reduce the forces on the tool, minimizing the risk of breakage. If you are unsure about the parameter range, it’s recommended to start with conservative values and gradually increase them, ensuring the tool works within an acceptable range.

· Regularly Inspect Tools: During machining, regularly inspect the condition of the tool, especially the cutting edges and body, to identify wear or cracks early and prevent sudden breakage.

· Choose Durable Tool Materials: Using more temperature- and shock-resistant tool materials such as coated carbide or ceramic tools can significantly improve the tool's ability to resist breakage.

· Precise Machine Alignment: Ensure that the machine tool alignment and calibration are precise to prevent tool breakage caused by equipment issues. High-rigidity tool clamping systems can effectively prevent tool misalignment during machining.

· Reduce Cutting Load: When processing harder materials or complex parts, appropriately reduce the depth of cut and feed rate to decrease the tool load and lower the likelihood of breakage.

Ⅳ. Causes and Countermeasures for Tool Chipping

Tool chipping is another common tool failure that typically occurs on the cutting edge of the tool. Chipping not only affects machining precision but also accelerates tool wear, ultimately shortening tool life.

· High Impact Forces: During the machining of hard materials or intermittent cutting, the tool may encounter sudden impact forces, leading to small cracks on the cutting edge and eventually causing chipping.

· Improper Tool Geometry: If the tool’s geometry is not well-designed or the cutting edge is too sharp, it can lead to chipping. This is especially common in high-speed cutting or under heavy loads when the tool is subjected to excessive pressure.

· Delayed Chip Removal: During machining, if chips are not cleared promptly, they may make secondary contact with the tool, causing the cutting edge to suffer additional impact forces, leading to chipping.

· Tool Overload: If the cutting force exceeds the design range of the tool or if the cutting conditions are improper, tool chipping is more likely to occur.

To address tool chipping, the following countermeasures can be implemented:

· Optimize Cutting Parameters: Appropriately reduce cutting speed and feed rate to prevent the tool from experiencing excessive impact, especially when machining hard materials. Maintain a stable cutting condition.

· Use More Impact-Resistant Tool Materials: Select tool materials with higher impact resistance, such as PCD (Polycrystalline Diamond) or CBN (Cubic Boron Nitride), which can effectively prevent chipping.

· Enhance Cooling and Lubrication: Adequate coolant flow can help maintain a low temperature for the tool, preventing brittle breakage due to overheating.

· Optimize Tool Geometry: Choose the appropriate tool geometry, particularly adjusting the sharpness and angles of the cutting edge according to the material properties to reduce the risk of chipping.

Ⅴ. How MINNUO Machine Tools Prevent These Problems

MINNUO machine tools not only improve tool material selection and geometric design but also provide efficient cooling and monitoring systems to help prevent excessive wear and chipping issues.

· High-Precision Tool Design: MINNUO tools optimize cutting edge angles and feature a smooth transition design in the cutting edge area, reducing sharp angles and minimizing the risk of breakage caused by cutting stress concentration.

· Premium Tool Materials: MINNUO uses coated carbide, enhancing the tool’s resistance to wear and extending its service life.

· Intelligent Monitoring System: Through real-time monitoring of tool conditions, potential issues are detected promptly, and appropriate adjustments to cutting parameters are made to prevent failure.

· Efficient Cooling: Equipped with high-precision temperature sensors, MINNUO machine tools automatically adjust the coolant flow and spray angles when temperatures exceed preset safety limits, ensuring the tool’s cutting area remains well-cooled.

Conclusion

Tool wear and chipping are often caused by improper cutting parameters, inappropriate tool material selection, and insufficient cooling, among other factors. We need to take measures such as adjusting processing parameters, choosing suitable tool materials, and performing regular maintenance to effectively prevent these issues.

If you encounter unresolved tool issues, feel free to contact MINNUO. We will provide professional, free consultation to address your concerns!