As an important technological equipment, molds play an important role in consumer products, electronics, automobiles, and aircraft manufacturing industries. To improve the level and quality of mold production technology is an important factor in the development of China's mold manufacturing industry. Because the use of high-speed cutting technology can significantly improve the mold production efficiency and mold accuracy and service life, it is gradually replacing the EDM finishing mold, and has been widely used by foreign mold manufacturing companies, becoming the trend of mold manufacturing. The advantages of high-speed cutting for mold processing The characteristics of mold processing are single-piece small batches and complex geometric shapes, so the processing cycle is long and the production efficiency is low. In the traditional mold processing technology, the finishing hardened mold usually uses EDM and artificial light repair process, and the post-processing takes a lot of time. Shortening the processing time and reducing the production cost are the main goals for the development of mold processing technology. In recent years, there have been many new technologies in the mold processing technology, such as high-speed cutting, CAD/CAE design simulation, rapid prototyping, EDM milling, and compound machining. Among them, the most attractive and the best are high-speed. Machining. The high-speed cutting die uses the high rotational speed and high feed rate of the machine tool to complete multiple production processes of the die by cutting. The superiority of high-speed cutting die mainly manifests in the following aspects: 1 High-speed roughing and semi-finishing greatly increase the metal removal rate. 2 High-speed cutting machine tools, tools and processes can be used to process hardened materials. For small molds, after the heat treatment of the material, the rough and finish machining can be completed in a single clamping; for large molds, rough machining and semi-finishing machining are performed before the heat treatment, and the heat treatment is hardened and then finished. 3 High-speed and high-precision hard cutting instead of smoothing, reducing a lot of time-consuming manual grinding, improve efficiency by 50% than EDM. 4 Hard-machining The final molding surface improves the surface quality and shape accuracy (not only the surface roughness is low, but also the surface brightness is high), and it is more advantageous for mold processing with complex surfaces. 5 It avoids the phenomenon of decarburization, burns and micro cracks caused by electric spark and grinding, greatly reduces the surface damage after mold finishing, and increases the die life by 20%. 6 The workpiece has less heat, cutting force is reduced, thermal deformation is small, and CAD/CAM technology is used for rapid processing of electrodes, in particular, electrodes with easily deformable shapes and thin walls. The advantages of high-speed cutting are attractive for mold processing, but at the same time, the high-speed cutting of molds requires high costs, the use of tools is highly demanded, and complicated computer programming techniques are required to support the equipment. High, therefore, due to capital, technology and other reasons, the domestic application of high-speed cutting die is not much, currently need to solve how to choose and apply high-speed machining tool, high-speed cutting tools, reasonable processing technology, tool path A series of problems such as programming layer and process experiment. High-speed cutting machine tools for processing molds When selecting a high-speed machine for high-speed cutting dies, pay attention to the following issues: (1) It is required that the spindle of the machine tool has large power and high rotation speed to satisfy rough and fine machining. Small-diameter tools are used for the finishing tool, and the spindle speed reaches 15000 to 20000rpm. Machines with spindle speeds below 10,000 rpm can perform roughing and semi-finishing. If it is necessary to satisfy the rough and fine machining at the same time in the production of large-size molds, the selected machine tool preferably has two spindles with two rotation speeds or two spindles with different specifications. (2) The rapid feed of the machine tool does not require high speed travel. However, it must have a relatively high processing feed speed (30 ~ 60m/min) and high acceleration and deceleration. (3) has a good high-speed, high-precision control system, and has high-precision interpolation, contour preview control, high acceleration, high-precision position control and other functions. (4) Selection of CAD/CAM software for high-speed machine tools, especially software for high-speed cutting tools. In the production of molds, the application of five-axis machine tools is gradually increasing. The combination of high-speed cutting tools has the following advantages: 1 It can change the tool cutting angle, cutting conditions, reduce tool wear, help to protect the tool and extend tool life; 2 processing route is flexible, Reduce tool interference, can process complex shape of the surface of the mold and deep cavity mold; 3 processing range, suitable for many types of mold processing. Five-axis machine tools usually have two types of work table and milling head type five-axis machine tools, which can be selected for the type of mold. In the milling head type five-axis machine tool, a five-axis machine tool that can replace the milling head and replace the electric spindle head can be used for the rough and finish machining of the mold. High-speed cutting tool technology High-speed machining requires a suitable tool. The application of cemented carbide coated cutting tools and polycrystalline ceramic cutting tools makes it possible to use both high hardness blades and a high-toughness matrix, which promotes the development of high-speed machining. The hardness of polycrystalline cubic boron nitride (PCBN) blades can reach 3500 to 4500 HV, and the hardness of polycrystalline diamond (PCD) can reach 6000 to 10000 HV. In recent years, Germany's SCS, Japan's Mitsubishi (Kombay) and Sumitomo, Switzerland's Sandvik, and the United States' Kenneth F.K. and other well-known foreign tool companies have introduced their own high-speed cutting tools, not only cutting tools for high-speed cutting of ordinary structural steel, but also Superhard tools such as ceramic cutting tools for direct high-speed cutting of hardened steels, especially coated tools, play a significant role in the semi-finishing and finishing of hardened steels. At present, the development of high-speed machining tools in China has a large gap with foreign countries, and the expensive price of imported tools has also become an important factor hindering the application of high-speed cutting tools. In general, when the acceleration of the tool and the tool holder is required to reach 3g or more, the radial runout of the tool is less than 0.015mm, and the length of the tool is not more than 4 times the tool diameter. According to SANDVIK's actual statistics, when high-speed milling is performed using a titanium carbonitride (TiCN) coated solid carbide end mill (58HRC), the roughing tool linear speed is about 100m/min, while the finish machining and super machining When finishing, the line speed exceeds 280m/min. According to the experience of domestic high-speed finishing molds, when the small-diameter ball-end cutter is used for mold finishing, the linear speed exceeds 400m/min. This has high requirements for tool materials (including hardness, toughness, and red hardness), tool shape (including chip removal performance, surface accuracy, balancing, etc.) and tool life. Therefore, in the high-speed hard-cutting finishing tool, not only high-speed machine tools must be selected, but also the tool and cutting process must be reasonably selected. In the high-speed processing of mold, we should pay attention to the following aspects: 1 According to different processing objects, a reasonable choice of carbide coated tool, CBN and diamond sintered layer tool. 2 Use small-diameter ball-end milling cutters to finish the surface of the mold. Usually the diameter of the finishing tool is <10mm. The diameter of the selected tool varies depending on the material being processed and the hardness. In the selection of tool materials, TiAIN ultra-fine grain carbide coated tools have good lubrication conditions. When cutting tool steel, it has better wear resistance than TiCN carbide coated tools. 3 Select the appropriate tool parameters, such as negative rake angle. High speed machining tools require higher impact toughness and thermal shock resistance than normal machining. 4 to take a variety of methods to improve tool life, such as the appropriate feed rate, feed method, lubrication methods, etc., in order to reduce tool costs. 5 using high-speed handle. At present, the HSK tool holders and hot press mounting tools are the most widely used, and attention should be paid to the overall dynamic balance of the spindle system after the tool is clamped. High-speed cutting die process technology In high-speed machining mold technology, process technology is a key factor in the use of machine tools and cutting tools. According to the current situation of domestic mold production, process technology has largely restricted the application of high-speed machining molds. On the one hand, due to the relatively short time for high-speed processing applications, relatively mature and systematic process systems and standards have not yet been formed; on the other hand, high-speed cutting processes have high test costs and require large investment and long time. High-speed cutting die process technology mainly includes: (1) High-speed cutting die process test for different materials In reference to foreign high-speed milling process parameters found that the foreign company's tool is based on imported materials to do the test, with its recommended parameters in the high-speed processing of domestic material mold, the effect is more obvious. Therefore, the use of foreign tools, in addition to the need to refer to the parameters provided by the manufacturer, the actual process test is also necessary. Domestic tool manufacturers rarely recommend the technical parameters of high-speed milling, so the use of domestic tools is more necessary to do tests to obtain satisfactory process parameters. It is best to use a fixed manufacturer's tool, through the test, to form a processing technology standards, and on this basis to optimize a set of processing parameters suitable for the company, and into the corporate standard. (2) Machining tool path and programming for high-speed cutting The tool path, feed method, and feed in the high-speed cutting die process technology are the main contents. Many toolpath approaches in high-speed cutting tooling technology are designed to reduce tool wear and increase tool life, so the tool's trajectory in high-speed cutting feeds is much more complex than normal machining. High-speed processing mold processing process should follow the following principles: 1 When finishing with a small-diameter tool, the cutting speed decreases as the hardness of the material increases. 2 Maintain a relatively steady feed and feed rate, continuous cutting load, reduce abrupt changes, slow down and slow down. Avoid chipping directly by vertical downward feed: The milling force of the slash path infeed gradually increases, the impact on the tool and the spindle is small, and the chipping can be reduced significantly; the spiral trajectory infeed cuts in, more suitable for the cavity mold High-speed machining. 3 small feed, knife cutting. Usually the feed is less than 10% of the cutter diameter and the feed width is less than 40% of the cutter diameter. 4 Keep uniform finishing allowance. 5 Maintain single-edge cutting. According to the above rules, there are the following commonly used feed path methods: 1 As far as possible, the milling movement of the straight corner is avoided; the spiral cutting feed is used at the corner to keep the cutting load stable. 2 Try to avoid the infeed and retract movement outside the workpiece and go directly from the contour to the next depth. Instead, it adopts oblique gradual feed cut-in or spiral cut-in. 3 Invariable feed per edge, feeds the machining plane with a helix or trochoidal path, and maintains single-edge cutting. The use of high-speed milling for milling to complete the hole not only improves surface quality, but also increases tool life. 4 Contour processing is kept on the level surface (contour line), and the depth of feed is the same for each layer. As you enter the next depth, feed in gradually. 5 When machining a smaller size such as a slot, use a tool with a smaller diameter than the shape to feed in a helix or trochoidal path to maintain single-edge cutting. Ultrasonic Sieve,Ultrasonic Vibrating Sieve,Ultrasonic Sieve Deblinding,Stainless Steel Coffee Sieve Xinxiang Zhenying Mechanical Equipment Co., Ltd , https://www.zhenyinggroup.com