New progress in cemented carbide tool grinding

Advanced and efficient cutting tools are one of the important factors in manufacturing industry to improve productivity and surface quality. In the high-grade NC machining center, one high-efficiency compound tool can be used instead of many single-function tools, and the complex shape workpiece can be automatically processed according to the machining program, which has an excellent effect on improving production efficiency, surface quality and reducing production cost. Statistical data show that the use of advanced and efficient cutting tools can significantly improve the cutting efficiency, and it is possible to reduce the production cost of parts by 10%-15%. Even if the cost of purchasing advanced and efficient cutting tools is increased by 50%, the cost of parts production is only about 1%. That is to say, the increase of tool cost is much lower than the decrease of production cost. . At the same time, advanced and efficient cutting tools also have various benefits such as reducing tool changing time and improving product quality. Therefore, considering comprehensively, the use of advanced and efficient cutting tools has a remarkable effect on improving machining efficiency and reducing production costs. Research, development and application of new advanced and efficient cutting tools is one of the development trends of machining in the future.

When the material, structure and shape of the tool and the selection of the grinding machine are determined, the grinding wheel becomes an important factor to determine the success of the grinding process. The technical content and quality of grinding wheel decide whether or not to produce high quality cutting tools which meet the design requirements.

Special metal bond strong slotted diamond wheel (METROX)

It is well known that before 2007, most of the carbide cutting tools in Europe and Japan used ultra-high temperature resin bonded diamond grinding wheels, and adopted the traditional deep cutting, small feed grinding process. Due to the limitation of resin bonded diamond grinding wheel, the greater the cutting depth, the greater the grinding resistance, and the more grinding heat generated in the grinding process, which affects the cutting efficiency and tool surface quality. To solve these problems, in 2007, Europe began to optimize tool grinders and diamond grinding wheels. In the grinding machine, the rigidity and power of the machine itself have been improved (the maximum power has reached 37 kW); in the diamond grinding wheel, a powerful grooved grinding wheel suitable for large cutting depth and large feed has been developed, which is used in conjunction with a high-power tool grinder to double the production efficiency and achieve good results in the market. Popularization and application.

Before 2007, due to the characteristics of the Japanese market and technological equipment constraints, still a large number of ultra-high temperature resin bonded diamond grinding wheels. Although the grinding wheel has high grinding accuracy and good surface finish, because the grinder power is small (generally less than 10 kW), so each feed depth is small, resulting in low grooving efficiency, it is difficult to meet the increasing market demand.

After 2007, according to the development trend of high-speed grinding in the world and the demand of China's cutting tool market, Oriental Corporation of Japan and Zhongyu Corporation of Shanghai have developed special metal bond strong grooved diamond grinding wheel (METROX) suitable for grinding carbide cutters with large cutting depth and feed rate. The grinding wheel adopts special metal bond, which solves the problem of "metal resistance" in grinding cemented carbide with general metal bond grinding wheel, and greatly improves the grooving efficiency of cemented carbide integral cutter. The grooving depth of the grinding wheel can reach 4 mm at one time, and the grooving feed rate of the grinding wheel can reach 90-120 mm/min at this cutting depth. At the same grinding depth, the feed speed of UHT resin bonded diamond grinding wheel can only reach 50 mm/min at most. If the feed speed is higher than this value, the high grinding temperature will cause oil mist and lead to the abnormal continuous machining.

When grooving with METROX grinding wheel, the workpiece will not produce cracks, burns and thermal deformation because of the low grinding resistance and low grinding temperature (the surface temperature of the grinding wheel is between 30 and 70 degrees Celsius). At the same time, due to the small loss of grinding wheel, the dressing cycle and service life of the grinding wheel are prolonged. Because of the characteristics of special metal binder, the wheel has excellent wear resistance and can keep the wheel sharp for a long time.

METROX grinding wheel can adopt very high feed speed, for example: when grinding three-groove cemented carbide cutters with 12 mm diameter, 30 degree helix angle and 26.5 mm groove length, when grinding depth is 4.0 mm and grinding wheel linear speed is 16 mm/s, feed speed can reach 90-120 mm/min; when grinding diameter is 16 mm, 30 degree helix angle and groove length is 50 mm, four-groove cemented carbide can be grinded. When the tool depth is 3.2mm and the grinding wheel speed is 16mm / s, the feed rate can reach 130mm / min.

Performance improvement of super high temperature resin bonded diamond wheel

Although the machining efficiency of ultra-high temperature resin bonded diamond grinding wheel is lower than that of METROX grinding wheel, the grinding wheel has the advantages of high bonding strength, short production cycle and low processing cost. Especially, it is not easy to break the edge when grinding the tool edge, and can be repaired into various shaped grinding wheels with complex shapes according to the application requirements. It is still widely used for a long time. How to further improve the grinding performance of this kind of grinding wheel has also become an important work at present.

With the rapid development of cutting tool design, manufacturing and use technolo