In addition to the tool that affects the quality of metal cutting, the reasonable choice of cutting fluid is more important
April 17, 2022
Through the accumulation of practical experience in production, we realize that certain factors in metal cutting can control and affect the surface quality of materials. These factors mainly include: cutting force, cutting fluid and tool material. In the metal cutting process, if these factors are reasonably selected and the metal cutting process is properly controlled, we can efficiently obtain high-quality products and get better profits.
1. The influence of tool material on metal cutting The service life and cutting efficiency of the tool are mainly determined by the tool material. The advanced and superior tool material will not only enhance the processing quality and cutting efficiency, but also prolong the service life of the tool, thereby further reducing the production cost. 1) The properties of the tool material By considering practical factors in metal cutting, the tool material should have high hardness, high strength, and good wear resistance, heat resistance and thermal conductivity. Only a tool material with high hardness can complete the cutting task, sufficient strength can ensure that the cutting process will not cause danger, and good heat resistance can ensure the machining work in a high temperature environment. Only in this way can we ensure the safe and efficient operation of processing. 2) Types of tool materials The types of tool materials are generally distinguished according to the physical and chemical properties of the material. In actual production, high-speed steel and cemented carbide are the most widely used. Carbon and alloy tool steels with poor heat resistance are mainly used for medium and low speed cutting due to their high bending strength. High-speed steel can be classified according to its use, usually divided into two categories: the first category, general-purpose high-speed steel; the second category, high-performance high-speed steel. Good manufacturability is a distinctive feature of general-purpose high-speed steel, and high-performance high-speed steel is based on general-purpose high-speed steel by adding trace elements, so the wear resistance and heat resistance of high-performance high-speed steel are significantly improved. The main component of the ceramic material is alumina, which is sintered after pressing. It has stable chemical properties, so it is suitable for higher cutting speeds. Diamond is the hardest tool material at present, which can not only complete the processing of non-ferrous metals, but also be used for high-speed finishing of non-metallic materials. Cubic boron nitride, a tool material second only to diamond in hardness and wear resistance. It is suitable for machining chilled cast iron and some difficult-to-machine materials.
2. The influence of cutting fluid on metal cutting 1) The role of cutting fluid In the process of metal cutting, cutting fluid plays an important role in cutting. Mainly divided into four points: First, the cooling effect. Cutting fluid often exists in the cutting area in the form of liquid. It can not only reduce the cutting temperature and play a cooling role, but also reduce the thermal deformation of the workpiece and the tool. Second, lubrication. The cutting fluid forms an oil film between the workpiece, the tool and the chips, reducing the friction between them and playing a lubricating role. Third, chip removal and cleaning. During production and processing, the cutting fluid is in a flowing state, which can wash away the fine chips on the cutting area and the machine tool. Fourth, anti-rust effect. The rust inhibitor is added to the cutting fluid to form a protective film on the metal surface, which can prevent the workpiece and the tool from rusting. 2) Types of cutting fluids Cutting fluids are mainly divided into three categories. The first type, water-insoluble cutting fluid, mainly has a lubricating effect on workpieces and tools. The second category, water-soluble cutting fluid, is mainly used for cooling and cleaning of workpieces and tools. The third category, surfactants, are soluble in both water and oil, and link water and oil together, so they have an emulsifying effect. 3) Selection of cutting fluid The choice of cutting fluid is often selected according to specific conditions such as workpiece material, processing method and tool material.
3.1) Select according to the workpiece material. Cutting fluid is required for cutting plastic materials, but not for brittle materials;
3.2) Choose according to the processing method. If grinding the material, choose a cutting fluid with cooling, cleaning and drainage and anti-rust functions. Extreme pressure cutting oils and extreme pressure emulsions can be considered if semi-closed or closed machining of the material. 3. Methods of controlling surface quality in metal cutting 1) Reasonable selection of tool materials The choice of tool material generally depends on the processing material and the specific processing situation. In the process of metal cutting, diamond knives are generally used for high-speed finishing of non-ferrous metals and non-metallic materials. The diamond knife has high hardness, good wear resistance and small friction coefficient. When high-speed finishing of carbon steel and alloy steel, coated cemented carbide or cubic boron nitride tool material can be used, which uses high hardness, good wear resistance, especially its chemical stability. 2) Reasonable selection of cutting fluid In order to reduce the friction between chips, tools and workpieces, it can be achieved by selecting a reasonable cutting fluid. The scientific application of cutting fluid can avoid sticking phenomenon and improve the quality of the processed surface. However, its use effect needs to be comprehensively considered with the tool material, workpiece material, processing method and other factors. Based on the above analysis, in the process of metal cutting, we must do the force analysis of the tool, the reasonable selection of cutting fluid, and the scientific application of tool materials in order to successfully complete the work. Only by completing these conscientiously and responsibly, we can effectively control the surface quality of the workpiece. Under this requirement, we can efficiently obtain high-quality products and obtain better benefits.
