With the rapid development of modern machinery manufacturing industry, the continuous innovation of cutting technology and cutting process has put forward higher requirements for the performance of cutting fluid. Especially in recent years, environmental protection and human health have increasingly become the focus of attention of the whole society, and cutting fluid will cause pollution and damage to the environment and human body, so the use of cutting fluid and waste liquid treatment have been increasingly restricted by environmental regulations. In developed industrial countries, the amount of smoke generated during machining with cutting fluid is also strictly limited. Some cutting fluid waste liquid and chips with cutting fluid are required to be treated as toxic materials, and the cost of treatment is increasing. In order to meet the requirements of social development, some new features have emerged in the development of modern cutting fluid technology.
1. Development of cutting fluid with high performance, long life and low pollution and research on waste liquid treatment technology In recent years, China has imported more and more advanced manufacturing equipment such as CNC machine tools and machining centers. If the required cutting fluid is imported for a long time, the production cost will rise significantly due to the high price. Therefore, it is urgent to develop high-performance cutting fluid to replace imported products. At present, water-based cutting fluid is used more and more widely in China, and has begun to transition from emulsion to synthetic cutting fluid and microemulsion with good performance and long service life. 2. Proper amount of cutting fluid The traditional cutting fluid supply method often uses the pouring method, especially for water-based cutting fluid, which is usually sprayed with a certain pressure and a large flow rate to cover the cutting area for lubrication and cooling. When the processing conditions change, such as changing the workpiece material or changing the tool type and geometric parameters, the cutting fluid amount is usually not (or rarely) adjusted. 3. Develop substitutes for traditional cutting fluids In this respect, liquid nitrogen cooling is the most studied. Nitrogen is the most abundant component in the atmosphere. As a by-product of the oxygen production industry, liquid nitrogen is very rich in resources. With liquid nitrogen as cutting fluid, it will volatilize directly into gas and return to the atmosphere after use, without any pollutants. From the perspective of environmental protection, it is a promising alternative to cutting fluid. One of the ways to use liquid nitrogen cooling is to spray liquid nitrogen as cutting fluid directly into the cutting area. Another method of using liquid nitrogen cooling is indirect use, that is, instead of spraying liquid nitrogen directly into the cutting area, liquid nitrogen is stored in the square box on the upper part of the polycrystalline CBN tool, which is input from the inlet and output from the outlet. When turning sintered silicon nitride in this way, the tool life is extended by 10 times and the wear is reduced by 1/4.
4. Dry Cutting At present, there are strict regulations in foreign countries that restrict the use of some cutting fluids, and the cost of waste liquid treatment is very high. For example, Germany spends about 1 billion marks on waste liquid treatment every year. Therefore, in the United States, Germany and other industrial developed countries are vigorously advocating the use of dry cutting technology. In some applications, chilling gas and cyclone sprayer can be used to reduce cutting temperature, such as jet cooling. It is predicted that in the future, if high-performance tool materials and chip breaking grooves with excellent chip removal performance are used together with cooling gas, the goal of no longer using cutting fluid can be achieved.
5. Development trend of modern cutting fluid In the field of cutting, it is far from completely replacing the wet machining using traditional cutting fluid, and the research and development of modern cutting fluid is more urgent. At present, the key points of research and development are as follows: vigorously develop cutting fluids with small negative effects on the ecological environment and human health and superior processing performance, and develop towards a green cutting fluid that is completely harmless to people and the environment; At the same time, efforts should be made to improve the liquid supply method, optimize the liquid supply parameters and strengthen the use management to extend the service life of cutting fluid and reduce the discharge of waste liquid; In addition, the technology of waste liquid recycling and harmless treatment should be further studied. Develop substitutes for traditional cutting fluids, and strengthen the research on practical technology, economic evaluation and scope of application. Research on dry cutting methods, seek the best fit of dry cutting tools, workpieces, machine tools and their parameters, and vigorously promote dry cutting application technology.
