Do You Know How to Prevent Edge Chipping in End Mills

Chipping refers to the phenomenon that the cutting edge is damaged or chipped due to excessive force or wear during the machining process of the end mill. This situation will directly affect the processing quality and increase the roughness of the workpiece surface. At the same time, edge chipping will significantly shorten the service life of the cutting tool and may even cause unexpected shutdowns during the machining process. This not only increases production costs, but may also cause workpieces to be scrapped, bringing unnecessary trouble and losses to the entire production process.

Milling Cutter Selection and Materials

Selecting Cutting Tool Materials with High Wear Resistance

When machining hard and difficult-to-machine materials, such as hardened steel, high-temperature alloys or composite materials, or when cutting for a long time, at high speed and at high temperature, the performance of the milling cutter faces great challenges. These materials and processing conditions place extremely high demands on the wear resistance and thermal stability of the cutting tool.

These materials can easily cause tool wear and chipping under high temperature and high stress conditions. To cope with this situation, it becomes crucial to select tool materials with high wear resistance. These highly wear-resistant materials not only significantly extend the service life of the tool, they also maintain the sharpness of the cutting edge. In this way, not only the processing efficiency is improved, but also the surface quality of the workpiece is improved.

Carbide, ceramic or CBN milling cutter tool materials can be used to meet these challenges. Carbide tools are ideal for high-speed cutting processes and maintain excellent performance at high cutting speeds. Ceramic cutting tools perform particularly well under high temperature conditions and can maintain stable cutting capabilities at extremely high processing temperatures. CBN (cubic boron nitride) cutting tools are particularly suitable for processing high-hardness materials such as quenched steel, which can significantly extend tool life and reduce wear.

Use Coated Cutting Tools

During the machining process, tools are prone to rapid wear and chipping due to the effects of high temperature and high friction. This is especially true under high-speed or dry cutting conditions, as the tools are subjected to greater thermal stress and friction in these harsh machining environments. These factors work together to cause the cutting performance of the tool to decline rapidly, affecting the processing quality and efficiency.

Coated tools form a hard protective layer on the cutting tool surface, effectively reducing friction and wear. This protective layer not only improves the heat resistance of the tool, enabling it to maintain stable performance in high temperature environments, but also significantly extends the service life of the tool. By reducing tool wear, coated tools maintain their cutting performance longer.

Coated cutting tools such as TiAlN (titanium aluminum nitride) and TiCN (titanium carbide nitride) can be used. TiAlN coated cutting tools are very suitable for high-speed cutting. Their excellent heat resistance and oxidation resistance enable them to maintain good cutting performance under high temperature conditions. On the other hand, TiCN-coated tools have higher hardness and wear resistance, and are particularly suitable for use at lower cutting speeds. The selection of these coated tools can improve machining efficiency and tool life based on specific machining needs and conditions.

Using Super-hard Materials to Make Cutting Tools

Cutting tool selection and processing conditions are particularly important when machining high-hardness workpiece materials, such as hardened steel, carbide, ceramics and composite materials, or when extremely high surface finish and machining accuracy are required. These high-hardness materials place strict requirements on tool performance. Choosing appropriate tool materials and coatings can significantly improve processing efficiency and ensure that the surface finish and processing accuracy of the workpiece meet expected standards.

Superhard material cutting tools, such as PCD (polycrystalline diamond), are particularly suitable for cutting high-hardness materials due to their extremely high hardness and wear resistance. PCD cutting tools can keep the tool sharp during the cutting process, significantly reduce tool wear, improve processing efficiency, and ensure excellent surface quality of the workpiece. This enables better machining results when processing high-hardness workpieces such as hardened steel, carbide, ceramics and composite materials.

PCD (polycrystalline diamond) tools are particularly suitable when machining hard and highly abrasive materials. PCD cutting tools have extremely high hardness and wear resistance, and can maintain excellent sharpness during the cutting process, thereby significantly improving the surface finish and dimensional accuracy of the workpiece.

Milling Cutter Cutting Tool Design and Installation

Optimizing End Mill Tool Geometry

When tool wear increases, cutting forces are excessive, or workpiece surface quality is poor during cutting, these problems can be improved by optimizing tool geometry. Optimizing tool geometry can help reduce cutting forces, reduce tool wear, and improve workpiece surface finish and machining accuracy.

By adjusting the rake angle, clearance angle, and lead angle of the tool, the distribution of cutting forces can be effectively optimized and heat and friction during cutting can be reduced. These adjustments help reduce tool wear, extend tool life, and improve workpiece surface quality.

• Rake angle: Increasing the rake angle can reduce cutting forces and friction, thereby reducing the burden on the tool and improving cutting performance and surface quality.
• Rake angle: Adjusting the rake angle can affect the strength and stability of the cutting edge. A reasonable rake angle design can help reduce tool wear during cutting.
• Lead angle: Optimizing the lead angle can help improve the distribution of cutting forces and reduce the contact pressure between the tool and the workpiece, thereby improving machining efficiency and the surface finish of the workpiece.

Adjust the rake angle, clearance angle, and lead angle of the tool to make it more suitable for specific machining conditions. For example, increasing the rake angle can reduce cutting force and improve chip evacuation; optimizing the back angle can improve tool wear resistance; and adjusting the main rake angle can improve cutting stability.

Improve Milling Cutter Tool Rigidity

• When the tool vibrates, deforms or the cutting accuracy is unstable during the cutting process.
• Improving the rigidity of the tool can reduce tool vibration and deformation, enhance cutting stability, and thus improve machining accuracy and tool life.
• Choose tool materials and designs with better rigidity, such as using carbide or overall structural design, to improve the rigidity and stability of the tool.

Adjust the Milling Cutter Installation Angle

During the cutting process, if the tool is unevenly stressed, unevenly worn, or the cutting efficiency is low, you need to consider adjusting the installation angle of the tool.

Ensuring the accuracy of the tool installation angle can optimize the distribution of cutting force and reduce uneven force and wear of the tool. This helps to improve cutting efficiency and extend the service life of the tool. The correct installation angle can ensure that the tool is evenly stressed during the cutting process and avoid local excessive wear, thereby improving the overall processing performance and tool stability.

When installing the tool, ensure the accuracy of the tool installation angle. Professional installation tools and methods can be used to accurately adjust the tool angle, such as tool aligners, angle gauges, etc. Check and calibrate the tool angle regularly to ensure that it is always in the best condition to avoid cutting problems caused by angle deviation. Through these measures, the force uniformity and wear of the tool can be effectively improved, and the cutting efficiency and tool life can be improved.

Processing Parameter Optimization

Reduce Tool Cutting Forces

During the cutting process, if the tool load is too large, tool wear increases, or edge chipping occurs, you need to consider reducing the cutting force.

Reducing cutting forces helps reduce mechanical and thermal stress on the tool, thereby extending tool life and reducing chipping and wear. This not only improves the stability of processing, but also improves the processing quality of the workpiece. Excessive cutting force will increase the wear of the tool and increase the risk of edge chipping. Therefore, reasonable control of cutting force is the key to ensuring the smooth progress of the machining process.

Cutting forces can be reduced through the following measures

• Reduce cutting speed: Reducing cutting speed can reduce the friction heat between the tool and the workpiece, thereby reducing the load on the tool.
• Reduce the feed amount: Reducing the feed amount each time can reduce the stress on the tool during the cutting process and reduce the cutting force.
• Reduce the depth of cut: Reducing the depth of cut can reduce the total load on each cut, thereby effectively controlling cutting forces.

By reasonably setting these parameters, controlling the force and heat during the cutting process, and ensuring that the tool works within a safe range, the use of the tool can be significantly improved, and the processing stability and workpiece quality can be improved.

Optimizing Cutting Parameters

Under different workpiece materials and cutting conditions, if there are problems such as low machining efficiency, poor surface quality or short tool life, you should consider optimizing cutting parameters.

Reasonable setting of cutting speed, feed rate and cutting depth according to specific machining conditions can achieve the best machining results. This optimization can balance machining efficiency, workpiece surface quality and tool life, thereby improving overall machining performance. Appropriate cutting parameters can reduce tool wear, improve machining stability, and ensure that the workpiece meets the expected quality standards.

Methods for optimizing cutting parameters include.

• Adjusting cutting speed: According to the workpiece material and tool type, adjust the cutting speed to improve machining efficiency and ensure that the tool can work under reasonable conditions.
• Adjust feed rate: According to machining requirements and tool capabilities, set appropriate feed rate to optimize the force and heat distribution during cutting, thereby improving machining quality.
• Adjust cutting depth: By adjusting the cutting depth, the load of each cut is controlled to avoid excessive cutting force and heat, thereby improving machining results.

The best combination of cutting parameters can be found through experiments and data analysis. Record the machining results under different parameter settings and analyze the data to determine which parameter combinations can effectively improve the machining results.

Multiple Shallow Cuts

When the milling cutter is overloaded during a deep cutting process and is prone to edge chipping or workpiece deformation, multiple shallow cuts are an effective solution.

By using multiple shallow cuts, the load on each cut can be significantly reduced, reducing the stress on the tool and workpiece. This method helps avoid cutting tool chipping and workpiece deformation, increases process stability, and improves machining quality. Each shallow cut can reduce cutting force and heat, thereby effectively extending the service life of the tool and improving the machining accuracy of the workpiece.

In order to perform multiple shallow cuts, you can take the following steps.

• Layered cutting: Divide the entire cutting process into multiple shallower cutting layers. For example, the total cutting depth is divided into several layers, and each layer is shallowly cut to reduce the load of each cut.
• Adjust cutting parameters: According to the thickness and material properties of the cutting layer, adjust the cutting speed, feed amount and cutting depth to adapt to the requirements of multiple shallow cuts.
• Monitor the processing process: When performing multiple shallow cuts, continuously monitor the tool status and workpiece condition during the processing to ensure that each cutting is performed within a reasonable load range.

By decomposing the cutting process into multiple shallow cuts, the stress of each cut can be effectively reduced, tool wear can be reduced, and edge chipping and workpiece deformation can be avoided.

Processing Technology Optimization

Controlling Chip Shape

When long chips are generated during the cutting process, causing them to wrap around the tool or workpiece, thus affecting machining efficiency and quality, measures need to be taken to control the shape of the chips.

By controlling the shape of the chips, the chips can be effectively prevented from wrapping around the tool, which helps to improve the stability of the cutting process and improve the surface quality of the workpiece. Long chips are easy to wrap around the tool or workpiece, which may cause machining interruptions, surface defects or tool damage. Therefore, optimizing the chip shape can promote the smooth discharge of chips and reduce the occurrence of these problems.

In order to control the chip shape, the following measures can be taken.

• Use a chip controller: Use a special chip controller or chip crushing device. These tools can help cut long chips into shorter fragments to prevent wrapping.
• Adjust cutting parameters: According to material properties and cutting requirements, optimize cutting speed, feed rate and cutting depth. For example, appropriately increasing the cutting speed or adjusting the feed rate can change the shape and length of the chips, making them easier to discharge.
• Choose the right tool: Use tools designed with special chip grooves or chip crushing functions. These tools can effectively control the shape of the chips and reduce wrapping problems.

Optimizing Workpiece Material Selection

When the workpiece material is difficult to cut during the machining process, resulting in increased wear of the end mill tool or low machining efficiency, it is necessary to consider optimizing the selection of workpiece materials.

Selecting a workpiece material with better machinability can effectively reduce tool wear, thereby improving machining efficiency and quality. Materials with better machinability are usually easier to cut, which can reduce tool load and wear, and improve machining stability and efficiency.

On the premise of meeting the performance requirements of the workpiece, the following measures can be taken to optimize the selection of workpiece materials.

• Choose materials that are easy to process: For example, use low-carbon steel, aluminum alloy and other materials instead. These materials usually have good machinability, can reduce tool wear and improve cutting efficiency.
• Consider the cutting characteristics of the material: When selecting a material, its hardness, toughness and cutting characteristics should be considered. For example, choose a material with moderate hardness and avoid materials that are too hard or difficult to cut to reduce the difficulty of machining.
• Optimize material processing technology: For some difficult-to-process materials, the material processing technology can be adjusted, such as heat treatment or surface treatment, to improve its cutting performance.

Improve Workpiece Surface Quality

When the workpiece surface quality is poor and there is a large cutting resistance during the cutting process, measures need to be taken to improve the surface quality of the workpiece.

By pre-treating the workpiece, its surface quality can be improved, thereby reducing cutting resistance, improving machining accuracy and the surface finish of the workpiece. Good workpiece surface condition helps to reduce friction and resistance during cutting, making the tool more stable during cutting, reducing surface defects and improving machining results.

The following pre-treatment processes can be performed before cutting to improve the surface condition of the workpiece.

• Polishing: Polish the workpiece to remove the roughness and uneven parts of the surface, obtain a smoother surface, and reduce friction during cutting.
• Deburring: Remove burrs from the workpiece surface to avoid burrs causing additional load on the tool or surface defects of the workpiece during cutting.
• Cleaning: Ensure that the workpiece surface is free of oil, impurities or other contaminants, which may affect cutting quality and efficiency.
• Homogenize the surface: Homogenize the workpiece to make its surface condition more consistent and reduce cutting resistance caused by surface unevenness.

Select the Appropriate Cutting Path

When processing complex shapes or large workpieces, if the cutting path design is unreasonable, resulting in excessive tool load or low processing efficiency, the cutting route needs to be optimized.

Optimizing the cutting path can effectively reduce the tool load, thereby improving processing efficiency and quality, and extending the tool life. A reasonable cutting path can avoid unnecessary repeated cutting, reduce tool wear, ensure the smoothness and efficiency of the processing process, and improve the processing accuracy and surface quality of the workpiece.

To select a suitable cutting route, the following measures can be taken.

• Analyze the shape of the workpiece: According to the geometric shape and characteristics of the workpiece, formulate a suitable cutting path. For example, for workpieces with complex shapes, the step-by-step cutting method is used to decompose complex cutting tasks into multiple simple cutting paths to reduce the load of each cutting.
• Optimize cutting strategy: Select a suitable cutting strategy, such as spiral cutting, step-by-step cutting, etc., to reduce the tool load and heat generation during the cutting process. Avoid excessive cutting depth and feed rate to reduce tool stress.
• Simulate the cutting process: Use cutting path simulation software to simulate and evaluate the impact of different cutting paths on tool load and processing efficiency. Select the best cutting path through simulation to avoid problems in actual processing.
• Consider tool load: When designing the cutting path, consider the load distribution of the tool to avoid excessive tool load. Reasonably arrange the cutting sequence and path to reduce tool wear and energy consumption.

Cooling and Lubrication

Improved Cooling

If a large amount of heat is generated during the cutting process, resulting in increased wear of the end mill tool or reduced surface quality of the workpiece, it is necessary to consider improving the cooling effect.

An efficient coolant system can quickly remove the heat generated in the cutting area, reduce the temperature of the tool and workpiece, thereby reducing tool wear and workpiece surface quality problems. Proper cooling can not only effectively control the cutting temperature, but also reduce the impact of thermal expansion on the workpiece and maintain machining accuracy.

In order to improve the cooling effect, the following measures can be taken.

• Use an efficient coolant system: Ensure that the coolant system can fully cover the cutting area and provide sufficient cooling capacity. Select a coolant with excellent cooling performance to more effectively remove the heat generated during the cutting process.
• Choose an appropriate coolant: Select a coolant with high thermal conductivity and excellent cooling effect, such as water-based coolant or oil-based coolant, and select the appropriate coolant type according to different processing requirements and material properties.
• Optimize the coolant spraying method: Adjust the spraying method and flow rate of the coolant to ensure that the coolant can be evenly sprayed on the cutting area to avoid incomplete coverage of the coolant and local overheating.
• Regularly check and maintain the cooling system: Regularly check the status of the coolant system to ensure the cleanliness and flow of the coolant to prevent system blockage or coolant deterioration that affects the cooling effect.
• Use a coolant circulation system: Using a coolant circulation system can continuously provide fresh coolant and maintain a stable temperature of the coolant to improve cooling efficiency.

Using High Pressure Coolant

When conventional cooling is not effective in high-intensity cutting or cutting of difficult-to-cut materials, it is necessary to consider using high-pressure coolant.

Increasing the pressure of the coolant can enhance its penetration and cooling effect, allowing the coolant to reach the cutting area more effectively and quickly remove the generated heat. This method helps to reduce tool wear and workpiece deformation, thereby improving the stability of the cutting process and processing quality.

In order to achieve efficient cooling effect, the following measures can be taken.

• Increase coolant pressure: Adjust the pressure of the coolant system and use high-pressure coolant to enhance the spray force of the coolant so that it can better cover and cool the cutting area.
• Use high-pressure coolant system: Use a specially designed high-pressure coolant system that can stably spray coolant at high pressure to ensure effective cooling of the cutting area.
• Ensure adequate coverage of the coolant: Optimize the spray angle and flow rate of the coolant to ensure that the coolant can evenly cover the entire cutting area and prevent heat from accumulating locally.
• Regularly maintain the cooling system: Regularly check and maintain the high-pressure coolant system to ensure its normal operation and avoid reduced cooling effect due to system failure.

Choose Appropriate Lubricant

During the cutting process, if the friction is large, resulting in high cutting heat and increased tool wear, it is necessary to consider choosing a suitable lubricant.

High-quality lubricants can effectively reduce the friction between the tool and the workpiece, thereby reducing the heat during the cutting process. Reducing friction can not only reduce tool wear, but also improve processing quality, ensure the surface finish and processing accuracy of the workpiece. Suitable lubricants can form a lubricating film, reduce heat accumulation, and maintain the best working condition of the tool and workpiece.

In order to choose a suitable lubricant, the following measures can be taken.

• Use high-quality lubricants: Select lubricants with good lubrication properties and thermal stability to reduce friction and reduce cutting heat. High-quality lubricants can form a stable lubricating film during the cutting process and reduce tool wear.
• Choose the type of lubricant suitable for cutting conditions: Choose the appropriate type of lubricant according to the specific cutting conditions and material properties. For example:

Oil-based lubricants: Suitable for high-temperature cutting environments, can provide good lubrication and cooling capabilities.

Water-based lubricants: Suitable for lower temperatures and high cutting speeds, with good cooling effects.

• Ensure good lubrication effect: During the cutting process, ensure that the lubricant can evenly cover the cutting area, regularly check the working status of the lubrication system, and ensure the effective supply and performance of the lubricant.
• Consider the environment and material characteristics: According to the characteristics of the workpiece material and the processing environment, select the appropriate lubricant type to maximize the lubrication effect and processing quality.

Preventing end mill chipping reflects the tenacious will of the cutting workers. They not only hold sharp tools in their hands, but also pursue perfect processing unremittingly. They know that every meticulous adjustment and every precise operation is the key to achieving high-quality processing. By continuously optimizing the process, and selecting suitable tools and cutting parameters, they are committed to eliminating every possible hidden danger to ensure the stability of the processing process and the excellent quality of the workpiece. In their eyes, keeping the tool sharp at every moment is not only a pursuit of excellence in technology, but also a persistence in their own craftsmanship and a persistent pursuit of excellent results.