When choosing an end mill for CNC milling, the properties and composition of the tool play a vital role in the final performance, machining accuracy, and machining speed. High-speed steel (HSS) and carbide end mills are common choices in the industry, and each material has its unique advantages and scope of application. High-speed steel end mills are known for their good toughness and strong impact resistance, and are suitable for general machining needs, especially in medium and low-speed machining environments.
Carbide end mills are known for their high hardness and wear resistance. They can maintain excellent cutting performance under high speed and high temperature conditions and are very suitable for high-speed machining and high-precision surface machining of materials. Choosing the right end mill cutter can not only improve machining efficiency, but also extend the life of cutting tools and reduce production costs. Therefore, a deep understanding of the characteristics and application scenarios of end mill bits materials is essential for optimizing CNC milling.
Advantages of High-speed Steel Milling Cutters
High-speed steel (HSS) tools began to be used in the 1930s and quickly became the standard tool in the field of cutting and milling. The emergence of high-speed steel tools completely changed the way of machining because they were more durable and versatile than previous tool materials. This material can not only withstand higher cutting speeds, but also has better impact resistance and toughness, making it perform well in various machining applications.
High-speed steel tools can effectively cut various metal materials, including steel, cast iron, copper, and aluminum, and are widely used in various industrial manufacturing processes. Its excellent performance and wide applicability make high-speed steel tools a very valuable investment, not only improving machining efficiency, but also significantly extending the service life of the tool, thereby reducing production costs. The development of high-speed steel tools marks an important milestone in cutting and milling technology, promoting the progress and development of the manufacturing industry.
Advantages of Carbide End Mills
On the other hand, carbide tools, as an effective alternative to diamond cutting tools, show excellent performance. Carbide is usually composed of materials such as cobalt and tungsten carbide, which are pressed and sintered through high-temperature and high-pressure processes to make the material more dense and strong. Tungsten carbide gives carbide tools extremely high hardness and wear resistance, while cobalt as a binder enhances the toughness and impact resistance of the tool. This combination allows carbide tools to maintain their structural integrity under extremely high temperatures and pressures, and are not prone to deformation or wear during cutting.
These characteristics of carbide tools make them very suitable for machining high-strength and high-hardness materials such as stainless steel, cast iron, nickel-based alloys, etc. They perform well under high-speed and high-load machining conditions, which can significantly improve machining efficiency and surface quality. In addition, carbide tools have a long service life, reducing the frequency of tool changes and downtime, thereby improving the overall efficiency of the production line.
Interestingly, the use of carbide inserts predates high-speed steel inserts. Although high-speed steel tools once had a significant advantage in cutting and milling due to their toughness and impact resistance at a certain stage in history, carbide tools have gradually regained market favor with the passage of time and technological advances. Early carbide tools had relatively low performance due to manufacturing process limitations, while modern carbide tools have been greatly improved through advanced design and manufacturing technology.
Contemporary carbide tools have made great progress in material ratios, manufacturing processes, and surface treatment technologies, which have significantly enhanced their hardness and wear resistance. Modern carbide tools can not only withstand higher cutting speeds and greater cutting forces, but also maintain excellent stability and durability in high-temperature and high-pressure environments. Compared to similar tools produced centuries ago, today’s carbide tools are much stronger, tougher and more durable in terms of strength, toughness, and service life.
Carbide End Mills vs HSS End Mills Heat Resistance Comparison
Carbide end mills and HSS end mills have significant differences in heat resistance. Machining processes, such as drilling and boring, generate high temperatures. Overheating is a serious problem that operators cannot ignore, as it can cause tool deformation, failure or significantly shorten tool life. Therefore, operators must actively regulate temperature through continuous monitoring and set up effective cooling mechanisms to maintain a stable machining environment.
Carbide end mills exhibit extremely high heat resistance due to the inherent high thermal resistance of their materials. This allows them to maintain excellent performance and stable shape under high-temperature conditions, thus providing high efficiency without affecting cutting results. Regardless of the operator’s skills and expertise, carbide end mills are able to meet processing needs in high-temperature environments, ensuring the continuity and quality of processing.
In contrast, although high-speed steel end mills have higher hardness and wear resistance, their alloy composition determines that they have poor stability at high temperatures. When the cutting temperature rises, the hardness of high-speed steel will drop significantly, causing the tool to wear and chipping. High-speed steel end mills tend to soften at high temperatures, limiting their cutting speed and feed rate, which is particularly disadvantageous in high-intensity, high-speed machining environments. Therefore, high-speed steel tools are more suitable for medium- and low-speed machining applications, while carbide end mills are undoubtedly a more ideal choice under high-temperature and high-load conditions.
Carbide end mills can provide higher machining performance and longer service life under high-temperature conditions due to their excellent heat resistance and stability. Although high-speed steel end mills perform well in certain specific applications, their insufficient heat resistance limits their application in high-temperature and high-load environments.
Comparison of Toughness Between Carbide End Mills and High-speed Steel
High-speed steel (HSS) is known for its excellent toughness, which means that it is not prone to chipping when subjected to shock or vibration. This property allows high-speed steel end mills to perform well in a variety of machining environments, especially when performing intermittent cutting, machining complex-shaped workpieces, or processing workpieces with uneven material hardness. Due to its good toughness, high-speed steel end mills are not easily damaged when impacted, which not only improves the stability of processing, but also significantly extends the service life of the tool. High-speed steel end mills are therefore ideal for many manufacturing industries with large changes in processing conditions and high-impact loads.
In contrast, carbide tools have relatively poor toughness. Although carbide is known for its high hardness and wear resistance, the tool is more likely to break when subjected to impact or vibration, especially when processing hard materials or under poor cutting conditions. This lack of toughness requires carbide tools to be used with special care in certain processing environments to avoid premature failure or damage to the tool.
However, carbide tools still perform well under appropriate conditions. To compensate for the lack of toughness, operators usually use more stable cutting conditions and appropriate cutting parameters to ensure that the tool can work in the best condition. At the same time, the development of modern manufacturing technology is also constantly improving the toughness of carbide tools, and by optimizing material ratios and advanced manufacturing processes, it has improved its impact resistance to a certain extent.
Wear Resistance Comparison Between Cemented Carbide End Mills and High-speed Steel
Cemented carbide end mills are mainly composed of hard phases such as tungsten carbide and binder phases such as cobalt. Tungsten carbide has extremely high hardness and is the main source of wear resistance of cemented carbide. Cemented carbide has a fine grain structure, and the carbide hard phase is evenly distributed in the binder phase to form a dense structure, which makes cemented carbide end mills have extremely high wear resistance. Due to this excellent wear resistance, cemented carbide end mills perform well in high-load and high-speed processing environments and can significantly extend the service life of the tool.
In contrast, high-speed steel end mills are a type of alloy steel. Although they also have high hardness, their wear resistance is far inferior to that of cemented carbide. High-speed steel has relatively large grains and more grain boundaries, which makes it easy to plastically deform during cutting, resulting in increased wear. Due to this weaker wear resistance, high-speed steel end mills have a shorter life under high-load and high-speed processing conditions, and require more frequent tool replacement, affecting processing efficiency.
The service life of carbide end mills is much higher than that of high-speed steel end mills. They can withstand higher cutting speeds and feeds, thereby achieving higher processing efficiency. In modern manufacturing, choosing carbide end mills can not only improve production efficiency, but also reduce the frequency of tool replacement and downtime, thereby reducing production costs. Therefore, despite the high initial cost of carbide end mills, their long-term economic benefits and processing advantages make them the preferred tool for many high-precision and high-efficiency processing scenarios.
Comparison of Finishing Performance of Carbide End Mills and High-speed Steel End Mills
End mills play a decisive role in machining operations such as milling, boring and tapping, and directly affect the finishing effect and final result of the workpiece. During the finishing process, defects such as burrs will not only weaken the appearance quality of the finished product, but may also cause dangers or obstacles to the performance of the parts. Therefore, it is crucial to ensure clean, smooth and accurate finishing effects during the machining process, which is the key to improving part compatibility and functionality in machining.
Carbide end mills excel in finishing performance, have a small thermal expansion coefficient and good dimensional stability. This means that in high-temperature processing environments, carbide end mills can maintain the stability of their size and shape, reduce processing errors caused by thermal expansion, and thus process workpieces with higher dimensional accuracy. In addition, the high hardness and wear resistance of carbide materials allow the tool to maintain a sharp cutting edge after long-term use, improving the finish and accuracy of the processed surface.
In contrast, high-speed steel end mills have a larger thermal expansion coefficient and poorer dimensional stability. Under high-temperature processing conditions, high-speed steel end mills are prone to thermal expansion, resulting in changes in tool size and shape, which affects the processing accuracy. As the hardness and wear resistance of high-speed steel decrease at high temperatures, the cutting edge of the tool is more likely to wear, which further reduces the finish and accuracy of the processed surface. Therefore, it is difficult for high-speed steel end mills to achieve the high precision and high quality standards that carbide end mills can achieve during the finishing process.
With their excellent thermal stability and high hardness, carbide end mills can provide excellent finishing performance in various complex and demanding processing environments. They can effectively reduce thermal expansion and tool wear problems during processing, thereby ensuring the dimensional accuracy and surface quality of the workpiece. Although high-speed steel end mills still have their unique advantages in some applications, their finishing performance in high-temperature and high-load environments is relatively low, which limits their application in high-precision machining.
Comparison of Economic Benefits Between Carbide End Mills and High-speed Steel End Mills
The unit price of carbide end mills is usually higher than that of high-speed steel end mills, mainly due to the higher cost of carbide materials, and its production and processing technology is also more complicated. The high hardness and wear resistance of carbide require more advanced technology and more sophisticated equipment in the manufacturing process, which increases production costs.
In most cases, carbide end mills are undoubtedly a better choice for machining tasks that pursue high precision and high efficiency. They can maintain excellent performance in high-load, high-speed and high-temperature environments, providing higher machining accuracy and longer service life. Although the initial investment is higher, its advantages in reducing downtime, reducing the frequency of tool changes and improving machining efficiency make its overall economic benefits more significant. In manufacturing industries that require high precision and high quality, such as aerospace, automotive manufacturing, and precision machining, the application of carbide end mills has greatly improved production efficiency and product quality, and in the long run, these advantages often offset their higher initial costs.
However, for some simple machining tasks or situations with limited budgets, high-speed steel end mills are still a good choice. High-speed steel end mills have a low manufacturing cost and a relatively small initial investment, and are suitable for machining environments with medium and low speeds, low loads, and low temperatures. Although its wear resistance and thermal stability are not as good as carbide end mills, its good toughness and impact resistance make it still perform well in many application scenarios. For example, in small and medium-sized enterprises or workshops, high-speed steel end mills are still widely used because of their high cost-effectiveness and easy maintenance and replacement.
In addition, high-speed steel end mills can provide stable machining results when dealing with intermittent cutting and machining of complex-shaped workpieces due to their good toughness and difficulty in chipping. This makes it still have advantages in many specific machining tasks.
disadvantages in CNC milling. High-speed steel end mills, with their toughness and impact resistance, excel in medium- and low-speed and complex workpiece processing, and are suitable for applications with limited budgets. Carbide end mills, with their hardness, wear resistance, and heat resistance, meet the needs of high-precision and high-efficiency processing. Although the initial cost is high, the economic benefits brought by their long life and high efficiency are also very considerable. It is crucial to choose the right tool material according to specific processing requirements and economic conditions, which not only affects the processing effect and efficiency, but also affects the production cost and the competitiveness of the enterprise. A deep understanding and reasonable application of the characteristics of the two tools will help optimize CNC milling processing.
