1. General characteristics of high-speed milling

High speed milling generally uses high milling speeds, appropriate feed rates, and small radial and axial milling depths. During milling, a large amount of milling heat is carried away by the chips, resulting in a lower surface temperature of the workpiece.

As the milling speed increases, the milling force slightly decreases, the surface quality improves, and the machining productivity increases accordingly. However, within the high-speed machining range, increasing milling speed will exacerbate tool wear. Because the spindle speed is very high, it is difficult for Cutting fluid to be injected into the processing area, so oil mist cooling or water mist cooling is usually used. The following is the effect of milling speed on machining performance.

2. Advantages of high-speed milling

Due to the characteristics of high-speed milling, high-speed milling technology has the following advantages compared to conventional machining:

(1) Improve productivity

The increase in milling speed and feed speed can improve the material removal rate. At the same time, high-speed milling can process hardened parts, and many parts can be clamped in one go to complete all processes such as rough, semi precision, and precision machining. For complex surface machining, it can also directly meet the surface quality requirements of the parts. Therefore, high-speed milling technology often saves processes such as electric machining and manual polishing, shortens the process route, and greatly improves processing productivity.

(2) Improving the machining accuracy and surface quality of workpieces

High speed milling machines must have high rigidity and precision, and due to low milling force and reduced workpiece thermal deformation, the machining accuracy of high-speed milling is very high. The milling depth is small, but the feed is fast, and the surface roughness is very small. When milling aluminum alloy, it can reach Ra0.4~0.6 μ m. When milling steel parts, it can reach Ra0.2~0.4 μ M.

(3) Realize the machining of integral structural parts

High speed cutting can enable aircraft to use a large number of integral structural parts, significantly reducing component weight, improving component reliability, and reducing assembly time.

(4) Beneficial for using tools with smaller diameters

High speed milling with smaller milling forces is suitable for using small diameter tools, which can reduce tool specifications and reduce tool costs.

(5) Beneficial for processing thin-walled parts and high-strength, high hardness brittle materials

High speed milling has low milling force and high stability, and can process thin-walled parts with high quality. By using high-speed milling, thin-walled parts with a wall thickness of 0.2mm and a wall height of 20mm can be processed. The processing of high-strength and high hardness materials is also a major feature of high-speed milling. Currently, high-speed milling can process parts with hardness up to HRC60. Therefore, high-speed milling allows cutting after heat treatment, greatly simplifying the mold manufacturing process.

(6) It can partially replace certain other processes, such as electric machining, grinding, etc

Due to the high quality of machining and the ability to perform hard cutting, high-speed milling can replace electrical machining and grinding in many mold processing.

(7) Significant improvement in economic benefits

Due to the above advantages, such as improved overall efficiency, improved quality, simplified process, increased investment in machine tools and cutting tools, as well as increased maintenance costs, the comprehensive economic benefits of high-speed milling technology still have significant improvements.

3. Problems with high-speed milling

High speed milling is a new technology that still has many shortcomings that need improvement, including:

(1) High speed milling machine tools are more expensive, requiring higher cutting performance, accuracy and dynamic balance of tools. fixed assets investment is larger, and the cost of tools will also increase;

(2) When increasing or decreasing the speed, the acceleration is greater, and the start and stop of the spindle exacerbates the wear of the guide rail, ball screw, and spindle bearing, leading to an increase in maintenance costs;

(3) Requires special process knowledge, specialized programming equipment, and fast data transmission interfaces;

(4) Lack of senior operators;

(5) Long debugging cycle;

(6) Emergency stop is actually impossible to achieve! Human errors, hardware or software errors can all lead to serious consequences;

(7) The safety requirements are very high: the machine tool must use the protective plate and Bulletproof glass with bulletproof function; The tool extension must be controlled; Do not use "heavy" knives and tool holders. Regularly check the fatigue cracks of the cutting tools, tool holders, and screws. When selecting a tool, it is necessary to pay attention to the allowable larger spindle speed and not use an overall high-speed steel tool.

4. Application of high-speed milling

High speed milling has many advantages and is being applied more and more widely, but there are also some shortcomings. Therefore, it is necessary to choose fields suitable for high-speed milling to apply this technology. The following table lists some application ranges of high-speed milling.

High speed milling has achieved successful applications in many fields, such as the use of high-speed milling technology for honeycomb structural components of aircraft to ensure machining quality, particularly large machining allowances for components such as beams, frames, and wall panels. High speed milling can improve productivity, and the use of high-speed milling for engine blades can solve the problem of difficult material processing; The vast majority of molds can be processed using high-speed milling technology, such as forging molds, die-casting molds, injection molding and blow molding molds, etc. The forging mold cavity is shallow and the tool life is longer; The die-casting mold has a moderate size and high productivity, while injection and blow molding molds are generally smaller in size and more economical. The graphite electrode and copper electrode for processing molds are also very suitable for high-speed milling; High speed milling is also suitable for rapid prototyping manufacturing of molds; The processing of thin-walled structures in electronic products is particularly necessary

High speed machining is required. Automotive engine parts are also an application field for high-speed milling. In addition, high-speed milling can also be used for prototype manufacturing.

5. Key Technologies of High Speed Milling

High speed cutting is a remarkable new technology in manufacturing technology, with a wide range of applications and a significant impact on the manufacturing industry. High speed cutting technology is the result of the comprehensive application and development of multiple new technologies such as new material technology, computer technology, control technology, and manufacturing technology. High speed cutting mainly includes the following basic theories and key technologies:

High speed cutting mechanism;

High speed cutting tool technology;

High speed cutting machine tool technology;

High speed cutting technology;

Testing techniques for high-speed machining, etc.

The technologies included in high-speed cutting are shown in the following block diagram: