Introduction to metal cutting
1 profile of metal cutting processing
With the development of science and technology, promote the production technology and technological innovation, in this case, the machining technology has been widely used. At present, metal machine parts after processing way is divided into plastic machining, mechanical processing, high energy, electricity and chemical processing several categories. And machining of cutting and grinding accounted for more than major in mechanical manufacturing process, wide range of USES. Therefore, in order to improve the efficiency of mechanical processing, reduce the cost of the production process at the same time, put a large amount of research in the cutting tool in China, the environment, such as cutting tool materials, deformation process, a large number of experiments and intelligent analysis, obtained the real and effective data. Unfortunately only a few manufacturers in the world to master the core database, holders can obtain key competitiveness and monopoly profits, the key mechanical equipment basic still rely on imports.
2 cutting tool geometry parameter
Metal cutting process is a process of interaction between tool and workpiece. Including cutting force, radial force and backward force three basic component, at the same time accompanied by friction heat effect, so that for the cutting tool cutting part of the surface quality of the degree of influence is very big. Easy to produce the devolop tumor, deformation or strain hardening etc. Bad phenomenon. General tool cutting plane of part of the surface of the knife, the knife after face, after the deputy blade surface of three. Rake surface of the chip discharge along its surface, and the control chip discharge direction, rake face in cutting with scraps of friction, easy to form high temperature concentration, and with high pressure, easy to produce binding effect, easy to form the devolop tumor. Main knife surface with workpieces after transition surface relative to the surface of the blade surface after vice is relative to the surface of the machined surface and workpieces have been, it is almost not involved in the cutting in the processing, but on the machined surface extrusion and friction, distortion and springback, fibrosis and work hardening. Points is given priority to the blade cutting edge, deputy blade, the transition edge. Main blade is also called the main cutting edges, it is after the rake face and the main knife surface intersection and the winger, to form the transition of workpiece surface, it completes the main metal removal work. Similarly, vice blade is called a cutting edge, is a former deputy after a knife knife surface and surface intersection winger, removal of the work, to form the workpiece machined surface. Transition is the main cutting edge and blade deputy section of the blade, the cutting edges together it can be a straight line or arc.
3 The influence of cutting tool materials, rational choice of the cutting tool In metal cutting processing cutting tool cutting part of the different materials of cutting tool durability and machining precision can also lead to different influence, now of the cutting tool material can be divided into the high speed steel, cemented carbide, coated tools, etc. High speed steel is divided into the common high speed steel, according to the use of high performance HSS and powder metallurgy high speed steel, common high speed steel with high hardness and wear resistance, a certain plasticity and toughness, suitable for manufacturing complex cutting tool, which can be used to cutting most of the cast iron artifacts, but in the use of common high speed steel cutting tools to ensure that when the cutting speed is not higher than 40-60 m/min, otherwise easy to cause collapse blade or rapid wear. High performance high speed steel is heated to 630 ℃ still can guarantee higher hardness, and durability in the high speed cutting is higher than common high speed steel, suitable for processing the high temperature alloys, austenitic stainless steel and other difficult machining, especially in high speed cutting. Powder metallurgy HSS manufacturing difficulty, high processing cost, strict production environment. But this kind of high speed steel grain fine and uniform, good processability and abrasion resistance. Suitable for manufacturing hard processing tools and precision tools. Carbide cutting tools are divided into YG, YT, YW class three. Due to increase the content of Co, which improves the bending strength of a tool, so the YG class is suitable for manufacturing small size cutting tool, and ensure that the lower cutting speed, used for processing hard machining. YT classes on the basis of YG class increased the TiC content, and enhance the wear resistance and hardness of the cutting tool, but the content of TiC is unfavorable and exorbitant, otherwise will make bending strength decreased obviously. Class YT cemented carbide
4 the influence of the working Angle of reasonable selection of tools Analysis of metal cutting, cutting tool Angle is indispensable. Tool Angle refers to the cutter figure need to mark the point of view of work. It is used for cutting tool manufacture, measurement and grinding. We usually use the annotation Angle with main Angle Kr, deputy Angle Kr ', anterior horn gamma o, after Angle alpha lambda s o, blade Angle and the auxiliary Angle after alpha o '. Main Angle of cutting tool durability influence is very big, the main Angle is bigger, the lower the tool life, this is because when the main Angle increases, then cutter Angle decreases, and tool cooling volume decreases, and cutting thickness, cutting width decreases, and the curve of the blade section length will be less, bear the load of unit area increased, heat dissipation condition is bad. When the Angle is too big, easy to result in collapse edge of point impact. So the reasonable cutting tool choice as far as possible little Angle. Deputy Angle formation is the main purpose of the final machined surface, deputy Angle shoulds not be too small, otherwise it will increase the vice friction on the surface of the blade and finished, after increasing the surface roughness and also to speed up the tool wear. Rake Angle depends on the size of the cutting edge sharp and strong. According to lee and schafer approximate shear Angle formula Φ + beta gamma o = PI / 4, the rake Angle, the greater the shear Angle change, chip deformation is reduced, so as to reduce the cutting force and cutting power, cutting head heat reduction, improve the endurance of a tool, but the anterior horn also shoulds not be too big, can reduce the wedge Angle, the cutting temperature. Through experiment that, under certain processing conditions, there is a before the tool life for the greatest Angle - reasonable anterior horn. After Angle is reduced after the main friction on the surface of the blade and processing. Appropriate after the increase of Angle can improve the tool life, incre
5 conclusion Through analyzing the cutting tool material, cutting tool working point of these properties, enable people to realize how to choose the correct reasonable cutting tools, help to improve the level of mechanization and speed up the industrialization process. As is known to all, metal cutting machine tool numerical control and flexibility, and the research and application of integrated production system is the development direction of modern machinery, a good machine only with a good knife can play the best effect, therefore, we must master the correct use of the cutting tool, to improve efficiency, reduce production costs, to bring the production efficiency.