New Development of Grinding Wheels with Cemented Carbide Tools

Advanced and efficient cutting tools are one of the important factors in the manufacturing industry to increase the productivity of processing and the surface quality of products. In the high-end CNC machining center, a single high-efficiency compound tool can be used to replace multiple single-function tools, and the processing of complex-shaped workpieces is automatically performed according to the machining program, which has an excellent effect on improving production efficiency, surface quality, and reducing production costs. Statistics show that the use of advanced and efficient cutting tools can significantly improve cutting efficiency and may reduce the production cost of parts by 10% to 15%. Even if the cost of purchasing advanced and efficient tools is increased by 50%, it is reflected in the cost of parts production. About 1%, that is, the increase in tool costs is far lower than the decline in production costs. At the same time, advanced and efficient tools also have various benefits such as reduced tool change time and improved product quality. Therefore, comprehensive consideration, the use of advanced and efficient tools to improve processing efficiency, reduce production costs is very significant, research and development and application of new advanced and efficient tools is one of the future development of machining.

When the high-efficiency tool is ground, 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 in determining the success or failure of the machining. The level of technical content of grinding wheels and the quality of the grinding wheel determine whether high-quality tools that meet the design requirements can be produced.

Special Metal Bonding Power Slotted Diamond Grinding Wheel (METROX)

As we all know, before 2007, Europe and Japan mostly used ultra-high-temperature resin bond diamond grinding wheels in the slotting process of carbide tools, and adopted the traditional large depth of cut, small feed grinding process. Due to the limitation of the resin bond diamond grinding wheel, the greater the cut depth, the greater the grinding resistance, and the more grinding heat generated during the grinding process, which affects the machining efficiency of the tool grooving and the tool surface quality. In order to solve the above problems, in 2007, Europe began to optimize new tools and diamond grinding wheels. In terms of grinders, the rigidity and power of the machine itself have been increased (maximum power has reached 37 kilowatts); in the case of diamond grinding wheels, powerful grooved grinding wheels suitable for large depths of cut and large feed have been developed and used with high-power tool grinding machines. The production efficiency has been doubled and achieved good results, and it has been promoted and applied in the market.

Before 2007, due to the characteristics of the Japanese market and the limitations of the process equipment, the ultra-high temperature resin bond diamond grinding wheel was still widely used. Although the grinding wheel has high grinding precision and good surface finish, due to the small grinding machine power (generally less than 10 kilowatts), the cutting depth of each feed is also small, resulting in low efficiency of slotting processing and difficulty in meeting the increasing market. demand.

After 2007, Japan's Oriental Corporation and Shanghai Zhongyu Company developed and developed special metal bonding agents suitable for deep cutting and large feed grinding of carbide cutting tools according to the development trend of international high-speed grinding processing and the needs of the Chinese cutting tool market. Groove diamond grinding wheel (METROX). The grinding wheel adopts a special metal bond to solve the problem that the general metal bond grinding wheel produces "metal confrontation" when grinding hard alloy, and greatly improves the grooving efficiency of the entire carbide cutting tool. The cutting depth of the grinding wheel can be up to 4mm. Under this cutting depth, the feeding speed of the grinding wheel can reach 90-120mm/min. At the same grinding depth, the feed rate of the ultra-high-temperature resin-bonded diamond grinding wheel can only reach 50 mm/min at the most. If the feed speed is higher than this value, the generated high temperature will cause oil mist, resulting in failure Continuous processing.

When grooving with METROX grinding wheel, the grinding temperature is low due to the small grinding resistance (after testing, the grinding wheel surface temperature is 30°C-70°C), so the workpiece will not have cracks, burns and thermal deformation. At the same time, due to the small loss of the grinding wheel, the dressing cycle and service life of the grinding wheel are prolonged. Due to the characteristics of the special metal bond, the grinding wheel has excellent wear resistance and can maintain the sharp state of the grinding wheel for a long time.

The METROX grinding wheel can be used with very high feed rates. For example, when grinding a three-slot carbide tool with a diameter of 12 mm, a helix angle of 30°, and a groove length of 26.5 mm, the grinding depth is 4.0 mm and the wheel speed is 16 mm/s. The feed rate can reach 90-120mm/min. When grinding four-slot carbide tools with 16mm diameter, 30° helix angle and 50mm groove length, the grinding depth is 3.2mm and the wheel speed is 16mm/s. The feed rate can reach 130mm/min.

Performance Improvement of Ultra High Temperature Resin Bond Diamond Grinding Wheel Although the processing efficiency of UHT resin bonded diamond grinding wheel is lower than that of METROX grinding wheel, due to its high bonding strength, short production cycle, and low processing cost, especially for grinding tool edge It is not easy to cause chipping, and it can be ground into a variety of complex shaped grinding wheels according to the requirements of use, so it is still widely used in production for a long time. How to further improve the grinding performance of such grinding wheels has also become an important task at present.

With the rapid development of tool design, manufacturing and use technologies, and the ever-increasing output of cutting tools, ultra-high temperature resin-bonded diamond grinding wheels still cannot fully meet the requirements for high-volume production of cutting tools. There is still room for further development in the number and quality of tools. . For this purpose, Shanghai Zhongyu Company is further studying how to improve the grinding performance of this type of grinding wheel. In particular, a large number of experimental studies have been conducted on the wear resistance of the bonding agent, the bonding strength of the bonding agent and the diamond abrasive, and self-sharpening properties. Great progress. The test results show that the improved wheel grinding efficiency can be increased by about 20% on the original basis, and the life of the grinding wheel can be increased by about 50%.