China's super-hard material products can be described in terms of varieties and specifications. In addition to reporting individual products due to domestic equipment conditions, etc., we can also manufacture them abroad. However, why do many superhard material products used in equipment imported from abroad cannot be supplied domestically? The key is the large difference in quality. Due to the low level of domestic super-hard materials, some domestic units have used the equipment of ordinary abrasive tools to give up the first-class equipment equipped with super-hard materials when introducing internationally advanced equipment. When the author visited the Ministry of Machinery officials in May 1995, a leader in charge of the bearing industry said: Because of the doubtful quality level of domestic CBN abrasive tools, a domestic bearing factory is introducing more than 20 sets of bearing grinding equipment in Japan. At the time, the equipment for the ordinary grinding wheel was selected, so that the equipment would not be stopped due to the grinding wheel problem after the introduction. Since the reform and opening up, various industries have introduced a lot of advanced equipment from abroad. Among them, there are many equipments that use diamond or CBN products. So far, have the grinding tools or tools used in these equipments been domestically produced? I am afraid that it is still far away. As far as I know, at least diamond wire saws, milling rolls for granite slabs, CBN grinding discs for machining cast iron parts for air-conditioning compressors, PCD and PCBN tools for the automotive industry, and various grinding rolls for processing wear-resistant floor tiles. Grinding wheels, inverted wheels, etc., for various reasons, national products (tested) have not been accepted by most users.
The author believes that improving the quality of super-hard materials should start from the following aspects.
First, improve the quality of abrasive grains (including PCD and PCBN), increase the variety, and achieve the "check-in" according to the purpose. The quality of the product is good and the abrasive grain is the decisive factor. It is hard to imagine how good the cutting effect of the saw blade made of MBD4 diamond is, in addition to the cheap price, so it is only necessary to solve the problem of difficult processing of hard and brittle non-metallic materials such as stone, glass and ceramics. The quality of coarse-grained diamonds is the real way out. The use of medium and low-grade diamonds to replace high-grade diamonds can only be an expedient measure, and does not help the development of the industry. In order to improve the quality of resin bond products, the quality problems of RVD diamond and CBNI abrasive grains must be solved. At the same time, the abrasive grains of microcrystalline structure should be developed, and the application of plated abrasive grains should be vigorously promoted. 90% of the abrasive grains of the resin in the advanced countries of the country are metal-coated abrasives, but China is probably less than 10%.
Second, a variety of binder formulations have been developed to accommodate different equipment types, processing objects, processing methods, and the like. The common problem in China is that there are few binder formulations, so it is difficult to meet different processing requirements. Foreign advanced superhard abrasives manufacturers, such as Germany's winterco. is an annual production of more than 10 million carats of diamond and CBN abrasives, with more than 100 binder formulations, according to different processing objects, processing methods Different conditions are adopted for the condition of the equipment. Even if the conditions of use are the same, special adjustments are made to the user's different usage habits. In addition, each formula of the company's resin binder has a hardness grade, which is divided into J, N, R, T four. For example: “K-888JYA†is a group code: K—888 refers to the resin bond diamond grinding wheel formula for processing cemented carbide. J—the hardness is soft, Y—for wet grinding, and A—for aluminum. The alloy is used as a matrix. There is no doubt that we have a big gap at this point.
Another problem with the binder is the selection of the binder. The resin binder is still taken as an example. The phenolic resin is basically used as a binder at home and abroad, and a small amount of polyimide is used as a binder. However, even if it is a phenolic resin, there are differences in performance and particle size. For example, the resins used in winterco. are jointly researched and developed with synthetic resin manufacturers to modify phenolic resins for abrasive materials. We used the same kind of abrasive grains and the same formula to make a comparison. The resin supplied by winterco. was made into the grinding wheel of the same specification with the resin produced by a domestic factory. The grinding ratio of the grinding wheel made of resin of winterco. The value of G can be 50% to 400% higher; in the case of large knives, it is impossible to compare. For example, when the depth of penetration is 0.08mm per stroke, the grinding wheel made of domestic resin can no longer be used, and the resin made by winterco. The grinding wheel has no effect. According to Mr. Maier, the company, after the resin enters the factory, special processing is required, and special attention is paid to the crushing technology. We have tested its samples with a particle size finer than 40 μm, of which 7 to 28 μm accounted for more than 90%.
For metal bond products, the characteristics of the joint agent in developed countries are that the abrasive tools are mainly copper-based, and the components are smelted into alloys according to the formulation ratio, and then processed into powders, so-called pre-alloyed powders. The composition of the bonding agent alloy is uniform, the ratio is accurate, and the alloying degree is sufficient and uniform during hot pressing. A variety of specialty bonding agents have also been developed, such as brittle bronze binders, cermet binders, and the like. Domestic pre-alloyed powder technology is still in the development stage and has not been used on a large scale for industrial production. The type of binder is also relatively simple, and it is inconvenient for difficult workpieces or high production efficiency and the accuracy of the workpiece.
The diamond tools used in the stone construction industry are mainly made of cobalt-based binders, supplemented by tungsten carbide and iron bases. In general, the product quality is stable and reliable. Due to resource and cost considerations, cobalt-based binders are rarely used in China, and iron-based materials are the main ones. Because the main component of iron powder is not dedicated to diamond tools, even the products of the same factory tend to be of quality. It is difficult to stabilize, not to mention the difference in the equipment, tooling, processing conditions of stone, construction industry, the difference in the technical quality of personnel and the diversity of the industry itself. It is difficult to meet the requirements of various aspects if the bonding agent is too single. The limitations of the formula are Users are deeply troubled, so the contradiction between supply and demand due to quality problems is also particularly prominent.
In addition to the continuous development of binder formulations for various applications, new types of binders should be continuously developed, such as new ceramic binders (porous ceramic binders, high wear-resistant binders), rubber binders, rubber-plastic binders. , new electroplated metal bond (suitable for use at high speed) and so on.
Third, improving the level of technology and product standards is an important part of improving the quality of super-hard materials. In this respect, in addition to continuous research and adoption of new process methods, we should continue to learn from foreign advanced technology methods for my use. For example, winterco. Grinding wheels and saw blades made of various binders generally use granulation technology to improve the uniformity of abrasive grain distribution in the products and create conditions for automatic feeding; the automated compounding system ensures that the mixing is accurate and mixed. The uniform material processing method has also been applied in large production; the abrasive hot pressing process adopts automatic control of temperature, pressure and time to ensure the density and ripening degree of the grinding tool; the shaping, trimming and edge-cutting process of the abrasive tool, The product has high precision and sharp sharpening, which reduces the trouble for users. These processes and measures should be carefully studied and adopted by us.
In terms of standards, although China's superhard material product standards have been revised and equivalently adopted international standards or foreign advanced enterprise standards, its key indicators, such as the precision and dynamic deviation of abrasive tools, are much different than those of foreign advanced enterprises. The key indicators in the winterco. corporate standard are now listed in the table below. It can be seen from the table that the most distinctive feature of the company's standards is that the dimensional accuracy of the substrate and the dynamic deviation of the abrasive tool are high, which is lacking in the Chinese standard.
The author believes that improving the quality of super-hard materials should start from the following aspects.
First, improve the quality of abrasive grains (including PCD and PCBN), increase the variety, and achieve the "check-in" according to the purpose. The quality of the product is good and the abrasive grain is the decisive factor. It is hard to imagine how good the cutting effect of the saw blade made of MBD4 diamond is, in addition to the cheap price, so it is only necessary to solve the problem of difficult processing of hard and brittle non-metallic materials such as stone, glass and ceramics. The quality of coarse-grained diamonds is the real way out. The use of medium and low-grade diamonds to replace high-grade diamonds can only be an expedient measure, and does not help the development of the industry. In order to improve the quality of resin bond products, the quality problems of RVD diamond and CBNI abrasive grains must be solved. At the same time, the abrasive grains of microcrystalline structure should be developed, and the application of plated abrasive grains should be vigorously promoted. 90% of the abrasive grains of the resin in the advanced countries of the country are metal-coated abrasives, but China is probably less than 10%.
Second, a variety of binder formulations have been developed to accommodate different equipment types, processing objects, processing methods, and the like. The common problem in China is that there are few binder formulations, so it is difficult to meet different processing requirements. Foreign advanced superhard abrasives manufacturers, such as Germany's winterco. is an annual production of more than 10 million carats of diamond and CBN abrasives, with more than 100 binder formulations, according to different processing objects, processing methods Different conditions are adopted for the condition of the equipment. Even if the conditions of use are the same, special adjustments are made to the user's different usage habits. In addition, each formula of the company's resin binder has a hardness grade, which is divided into J, N, R, T four. For example: “K-888JYA†is a group code: K—888 refers to the resin bond diamond grinding wheel formula for processing cemented carbide. J—the hardness is soft, Y—for wet grinding, and A—for aluminum. The alloy is used as a matrix. There is no doubt that we have a big gap at this point.
Another problem with the binder is the selection of the binder. The resin binder is still taken as an example. The phenolic resin is basically used as a binder at home and abroad, and a small amount of polyimide is used as a binder. However, even if it is a phenolic resin, there are differences in performance and particle size. For example, the resins used in winterco. are jointly researched and developed with synthetic resin manufacturers to modify phenolic resins for abrasive materials. We used the same kind of abrasive grains and the same formula to make a comparison. The resin supplied by winterco. was made into the grinding wheel of the same specification with the resin produced by a domestic factory. The grinding ratio of the grinding wheel made of resin of winterco. The value of G can be 50% to 400% higher; in the case of large knives, it is impossible to compare. For example, when the depth of penetration is 0.08mm per stroke, the grinding wheel made of domestic resin can no longer be used, and the resin made by winterco. The grinding wheel has no effect. According to Mr. Maier, the company, after the resin enters the factory, special processing is required, and special attention is paid to the crushing technology. We have tested its samples with a particle size finer than 40 μm, of which 7 to 28 μm accounted for more than 90%.
For metal bond products, the characteristics of the joint agent in developed countries are that the abrasive tools are mainly copper-based, and the components are smelted into alloys according to the formulation ratio, and then processed into powders, so-called pre-alloyed powders. The composition of the bonding agent alloy is uniform, the ratio is accurate, and the alloying degree is sufficient and uniform during hot pressing. A variety of specialty bonding agents have also been developed, such as brittle bronze binders, cermet binders, and the like. Domestic pre-alloyed powder technology is still in the development stage and has not been used on a large scale for industrial production. The type of binder is also relatively simple, and it is inconvenient for difficult workpieces or high production efficiency and the accuracy of the workpiece.
The diamond tools used in the stone construction industry are mainly made of cobalt-based binders, supplemented by tungsten carbide and iron bases. In general, the product quality is stable and reliable. Due to resource and cost considerations, cobalt-based binders are rarely used in China, and iron-based materials are the main ones. Because the main component of iron powder is not dedicated to diamond tools, even the products of the same factory tend to be of quality. It is difficult to stabilize, not to mention the difference in the equipment, tooling, processing conditions of stone, construction industry, the difference in the technical quality of personnel and the diversity of the industry itself. It is difficult to meet the requirements of various aspects if the bonding agent is too single. The limitations of the formula are Users are deeply troubled, so the contradiction between supply and demand due to quality problems is also particularly prominent.
In addition to the continuous development of binder formulations for various applications, new types of binders should be continuously developed, such as new ceramic binders (porous ceramic binders, high wear-resistant binders), rubber binders, rubber-plastic binders. , new electroplated metal bond (suitable for use at high speed) and so on.
Third, improving the level of technology and product standards is an important part of improving the quality of super-hard materials. In this respect, in addition to continuous research and adoption of new process methods, we should continue to learn from foreign advanced technology methods for my use. For example, winterco. Grinding wheels and saw blades made of various binders generally use granulation technology to improve the uniformity of abrasive grain distribution in the products and create conditions for automatic feeding; the automated compounding system ensures that the mixing is accurate and mixed. The uniform material processing method has also been applied in large production; the abrasive hot pressing process adopts automatic control of temperature, pressure and time to ensure the density and ripening degree of the grinding tool; the shaping, trimming and edge-cutting process of the abrasive tool, The product has high precision and sharp sharpening, which reduces the trouble for users. These processes and measures should be carefully studied and adopted by us.
In terms of standards, although China's superhard material product standards have been revised and equivalently adopted international standards or foreign advanced enterprise standards, its key indicators, such as the precision and dynamic deviation of abrasive tools, are much different than those of foreign advanced enterprises. The key indicators in the winterco. corporate standard are now listed in the table below. It can be seen from the table that the most distinctive feature of the company's standards is that the dimensional accuracy of the substrate and the dynamic deviation of the abrasive tool are high, which is lacking in the Chinese standard.
Waterjet Cutter Intensifier Parts
Poppet Retainer,Poppet Pin,High Pressure Seat,Inlet Poppet Valve,Inlet Compression Spring,Poppet Retaining
Poppet Retainer,Poppet Pin,High Pressure Seat,Inlet Poppet Valve,Inlet Compression Spring,Poppet Retaining
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