Development and Prospect of the hottest high speed

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Development and Prospect of high speed cutting technology

cutting is one of the most widely used machining methods, and high speed is its important development direction, including high-speed soft cutting, high-speed hard cutting, high-speed dry cutting, large feed cutting and so on. High speed cutting can greatly improve the production efficiency and the material removal rate per unit time, improve the surface quality and reduce the processing cost

1 the concept of high-speed cutting and high-speed cutting technology

high-speed cutting is a relative concept, and there is no consensus on how to define it. Moreover, because different machining methods and different workpieces have different high-speed cutting ranges, it is difficult to give an exact definition of the speed range of high-speed cutting

high speed cutting technology is based on the full development of machine tool structure and materials, machine tool design and manufacturing technology, high-speed spindle system, rapid feed system, high-performance CNC control system, high-performance tool holder system, high-performance tool materials and tool design and manufacturing technology, high-efficiency and high-precision measurement and testing technology, high-speed cutting mechanism, high-speed cutting technology and many other related hardware and software technologies. Therefore, high-speed machining is a complex system engineering, involving machine tools, cutting tools, workpiece, processing parameters and cutting mechanism

2 foreign development status of high-speed cutting technology

from German carl J. Dr. Salomon put forward the concept of high-speed cutting and applied for a patent in the same year. Since then, the development of high-speed cutting technology has experienced four stages: the theoretical exploration stage of high-speed cutting, the application exploration stage of high-speed cutting, the preliminary application stage of high-speed cutting, and the more mature stage of high-speed cutting. Now it has been popularized and applied in production. Especially since the 1980s, the industrial developed countries have successively invested a lot of human and financial resources in the research and development of high-speed cutting technology and related technologies, which has developed rapidly

in recent years, foreign high-speed machining machines have developed rapidly. The United States, France, Germany, Japan, Switzerland, Britain, Canada, Italy and other countries have developed their own high-speed cutting machines. High speed spindle is the most important key technology of high-speed cutting technology. It usually adopts motorized spindle components with the integration of spindle and motor to realize direct transmission without intermediate links. The spindle support generally uses ceramic bearings, hydrostatic bearings, hydrodynamic bearings, air bearings, oil-gas lubrication, jet lubrication and other technologies, as well as magnetic bearings. The feeding system began to use linear motors or ball screws with small lead, large size and high quality or multi head screws with large lead to provide higher feed speed and better acceleration and deceleration characteristics, with a maximum acceleration of 2 ~ 10g. The CNC control system uses multiple 32-bit or 64 bit CPUs to meet the requirements of high-speed machining for the system's fast data processing ability, and adopts feedforward and a large number of advanced program segment processing functions to ensure the interpolation accuracy during high-speed machining. Strong high-pressure and efficient cooling system is adopted to solve the problem of extremely hot chip. Temperature controlled circulating water (or other media) is used to cool the spindle motor, spindle bearing, linear motor, hydraulic oil tank, electrical cabinet, and some even cool the spindle box, beam, bed and other large components. Take more complete safety assurance measures to ensure the safety of machine tool operators and on-site personnel around the machine tool, and avoid the damage of machine tools, cutting tools, workpieces and related facilities; Identify and avoid working conditions that may cause major accidents; Ensure product output and quality

study the influence of the material characteristics of the workpiece on the processing method. Some difficult to machine materials, such as nickel base alloy, titanium alloy and fiber reinforced plastic, become easy to cut at high speed. In addition, the optimal cutting speed of different materials is also different, and the workpiece material is also an important basis for selecting cutting tools and processing parameters. Generally, in high-speed machining, high speed, medium and small cutting depth, fast feed and multi stroke should be adopted. However, in the selection of process parameters for high-speed machining, there is currently no practical production oriented database available for reference internationally

The research on the mechanism of high-speed cutting mainly includes the chip forming mechanism, cutting force, cutting heat change law and the influence law of tool wear mechanism on machining efficiency, machining accuracy and machined surface integrity in the process of high-speed cutting. At present, the research on the mechanism of high-speed cutting of aluminum alloy has achieved relatively mature conclusions, and has been used to guide the production practice of high-speed cutting of aluminum alloy. However, the research on the mechanism of high-speed cutting of ferrous metals and difficult to machine materials is still in the exploratory stage, and its high-speed cutting process specification is still very imperfect, which is not only the difficulty in high-speed cutting production, but also the focus of research in the field of cutting. In addition, high-speed cutting has entered the application of reaming, tapping and so on, and its mechanism is also constantly being studied. At present, the cutting force, cutting temperature, tool wear and tool life during high-speed cutting, more and more plastic enterprises are committed to the research and development of new environmentally friendly materials, and the changing laws of machining surface quality and machining accuracy need to be further studied and discussed

3 domestic development status of high-speed cutting technology

the research and application of high-speed cutting in China started late, but it has attracted widespread attention since the 1990s. At present, there are more than 3 million machine tools in the country, most of which are general-purpose machine tools. CNC machine tools, including economic ones, account for about 10%, and imported CNC machine tools and machining centers account for a large proportion in aviation, aerospace, automotive, mold, machine tools, engineering machinery and other industries. At present, 10000 ~ 15000r/min vertical machining centers and 18000r/min horizontal machining centers have been successfully developed and produced in China. The maximum speed of the high-speed digital profiling milling machine has reached 40000 R/min, 3500 ~ 4000R/min CNC lathes and turning centers have been produced in batches, and 8000r/min CNC lathes have also been produced. The high-end CNC system and open CNC system of high-speed machine tools are under in-depth research, but at present, they mainly rely on imports. At present, China is gradually promoting the application of high-speed cutting technology, which is mainly used in aerospace, mold and automotive industry. It processes aluminum alloy and cast iron more, but the tools used are mainly imported

at present, domestic tool materials are still dominated by high-speed steel and cemented carbide tools. Although advanced tool materials (such as coated cemented carbide, cermet, ceramic tools, CBN and PCD tools, etc.) have a certain foundation, they are not widely used. Generally speaking, the cutting speed is generally low, and the cutting level and machining efficiency are low. The research on the basic theory of high-speed cutting started relatively late. Since the 1980s, China has systematically studied the rules of chip formation, cutting temperature, cutting force, tool wear and damage, tool life and machined surface quality during high-speed hard cutting with ceramic tools, and has been widely used in production. Since the 1990s, the cutting force, cutting temperature, tool wear and damage and tool life of high-speed cutting of aluminum alloy, steel, cast iron, superalloy, titanium alloy, etc. have been studied and discussed, but no comprehensive and systematic research has been carried out. There are many researches on the monitoring technology of cutting process, but few of them are put into production. Attached table high speed cutting speed pelletizer operation of various processing methods, including machine equipment, adjustment, commissioning, operation, protection and repair, 1 series of links range

processing mode cutting speed (m/min) turning 700 ~ 7000 milling 300 ~ 6000 drilling 200 ~ 1100 broaching 30 ~ 75 reaming 20 ~ 500 grinding 5000 ~ 10000

Application of high speed cutting

due to the rapid progress of high speed cutting machine tool and tool technology and related technologies, High speed cutting technology has been applied in aviation, aerospace, automobile, mold, machine tool and other industries, such as turning, milling, boring, drilling, pulling, reaming, tapping, grinding aluminum alloy, steel, cast iron, titanium alloy, nickel based alloy, lead, copper and copper alloy, fiber-reinforced synthetic resin and almost all materials that can be processed by traditional cutting, as well as materials that are difficult to be processed by traditional cutting. Cutting tool materials mainly include carbon tool steel, ultra high speed steel, cemented carbide, coated cutting tools, ceramic cutting tools, cubic boron nitride, natural diamond, artificial diamond, polycrystalline diamond, etc

at present, the international high-speed machining technology is mainly used in the automotive industry, the machining field where the workpiece itself or the tool system is not rigid enough, and the field of machining complex curved surfaces. Different machining methods and workpiece materials have different high-speed cutting ranges. The range of linear speed of high-speed cutting in different processing methods is shown in the attached table. The attached figure shows the speed range of several common workpiece materials during high-speed milling

high speed cutting is still in the process of further development. It is expected that the cutting speed of milling aluminum can reach 10000m/min, processing cast iron can reach 5000m/min, and processing ordinary steel will also reach 2500m/min; The cutting speed of drilling aluminum can reach 30000r/min, the processing speed of cast iron can reach 20000r/min, and the processing speed of ordinary steel can reach 10000r/min

5 problems and development prospects of high-speed cutting

high speed cutting is one of the main directions of cutting development. In addition to relying on the development of basic technologies such as numerical control technology, microelectronics technology, new materials and novel components, it also has a series of technical problems that need to be solved urgently, such as serious tool wear, damage of high-speed cutting tools when cutting in and out, expensive tool materials for high-speed cutting, milling Boring and other rotary tools and spindles need dynamic balance, tool clamping should be reliable and safe, the spindle system is expensive and short life, and the high-speed machining machine tool and its control system that are easy to fracture are expensive, which makes the one-time investment of high-speed cutting larger. These problems restrict the further promotion and Application of high-speed cutting. The development trend and future research directions of high-speed cutting are summarized as follows: (1) the development and research of a new generation of high-speed and high-power machine tools; (2) Research on dynamic characteristics and stability of high speed cutting; (3) Deep research on the mechanism of high-speed cutting; (4) The development of a new generation of tool materials with good thermal vibration resistance, good wear resistance and long service life and the research of tool structure suitable for high-speed cutting; (5) Further expand the range of high-speed cutting workpiece materials and high-speed cutting processes; (6) Develop monitoring technology suitable for high-speed machining status; (7) Establish high-speed cutting database and develop programming technology suitable for high-speed cutting to further promote high-speed cutting technology; (8) Based on high-speed cutting technology, develop and promote dry (quasi dry) cutting green manufacturing technology; (9) Based on high-speed cutting, develop and promote high-energy machining technology

6 Conclusion

developing advanced manufacturing technology, revitalizing China's manufacturing industry, and meeting the challenges of the new century are the foundation of building a strong industrial country. High speed cutting technology is an advanced manufacturing technology, which has broad application prospects. The popularization and application of high-speed cutting technology can not only greatly improve the efficiency and quality of machining, reduce costs, but also drive the development of a series of high-tech industries. It is urgent to strengthen the basic research of high-speed cutting technology, establish high-speed cutting database and high-speed cutting safety technical standards, improve the development and innovation ability of machine tool and tool industry, and speed up the research, development and industrialization of high-speed cutting tool system and high-speed cutting machine tool system. (end)

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