High-speed, high-efficiency, high-precision, low-cost grinding technology CBN (CubicBoronNitride) is another superhard material first synthesized by GE in the United States after the advent of synthetic diamond. China successfully produced CBN in 1966, and it has been nearly forty years old. CBN has a hardness lower than that of diamond, but has superior heat resistance to diamond and chemical inertness to iron group metal materials. CBN abrasives made of these excellent properties as abrasive materials are particularly suitable for the grinding of various iron-based metal materials. It and diamond are mainly used to process hard and brittle materials to complement each other, which greatly expands the application range of superhard materials. Compared with ordinary abrasive tools, CBN abrasive tools are characterized by high speed, high efficiency, high processing quality, long life and low cost. They can be used as the tool of choice for high-efficiency and high-precision grinding of high-speed CNC grinding machines. It has a wide range of applications in the automotive, machine tools, tools, bearings and other industrial fields. 1. Properties of CBN When using CBN as an abrasive material, we mainly study its properties such as hardness, wear resistance, strength and thermal conductivity.
â—†The hardness of CBN is much higher than other ordinary abrasives. High hardness means stronger cutting ability and sharper;
â—†CBN has high wear resistance, which means it is more difficult to wear than ordinary abrasives. The ability to maintain the shape of the abrasive particles is one of the main characteristics of CBN as a high performance abrasive;
â—†CBN has a high compressive strength, which means it can keep particles intact and not easy to break when used under harsh conditions;
â—†CBN has good thermal conductivity and can be cold cut during grinding. Due to the different properties of CBN and diamond, the range of materials they process varies. CBN is suitable for processing tools such as tool steel, bearing steel, alloy steel, super alloy, and cast iron. The materials suitable for processing diamond are cemented carbide, glass, ceramic, cermet, cast iron. 2. CBN Grinding System CBN Abrasives are a tool for bonding CBN abrasives together and forming a shape with different types of bonding agents. It can only maximize its function by relying on the reasonable grinding process and relying on the superior performance of the grinding machine. In the research and application of CBN grinding technology, CBN grinding tools, grinding machines, workpieces, dressing, cooling, grinding processes and other factors must be integrated into a system to optimize, in order to obtain the best technical and economic effects. Several important factors to consider in CBN grinding technology are as follows. 2-1CBN Abrasives mainly consider the shape, size, CBN abrasive particle size, concentration, binder type and speed of use when manufacturing and selecting abrasive tools.
â—†The shape, size and marking of CBN grinding tools are in accordance with GB/T6409.2-1996 and GB/T6409.1-1994 standards;
â—† Among the four binders (resin, metal, ceramic, electroplating) of CBN abrasives, ceramic binders are the fastest growing. This is because the ceramic CBN grinding tool has high grinding efficiency, good shape retention, high durability, easy dressing and long service life of the grinding wheel, thus becoming the first choice for efficient and high-precision grinding.
â—†The concentration of the grinding wheel indicates the number of abrasive grains involved in grinding on the working surface of the grinding wheel during grinding. High concentrations result in high grinding ratios and low workpiece surface roughness. For example, the 200% concentration is 4-5 times longer than the 100% concentration wheel.
â—† The hardness grade of the abrasive tool indicates the amount of bonding force to the abrasive. The uniformity and stability of the hardness of the grinding wheel and the reasonable choice of hardness are important prerequisites for ensuring the quality of the grinding. The 2-2 grinding machine is the center of the grinding system. The performance of the grinding machine has the most important effect on the grinding effect, especially for CBN grinding.
â—† Improve the working speed of the grinding wheel, which can significantly improve the grinding efficiency, grinding ratio and surface quality of the workpiece. The use speed of 80~125m/s has become one of the basic characteristics of CBN special camshaft grinding machines imported from China. Using high speeds as much as possible is an important prerequisite for improving the technical and economical aspects of CBN grinding.
â—†High-speed grinding and CBN grinding wheel grinding characteristics require high rigidity and good vibration resistance of the machine tool spindle and the whole. This is the basic requirement for the grinding machine in CBN high-speed grinding technology. Without such a condition, in the case of using a CBN grinding wheel, in order to obtain a higher metal removal amount, the geometric accuracy and surface quality of the workpiece are deteriorated. Ripple is a common surface quality defect that is produced by vibration. The cause of vibration is that the machine tool has low rigidity, poor vibration resistance or unreasonable design of the grinding wheel parameters, resulting in excessive grinding force.
2-3 dressing using diamond roller dressing can not only improve the dressing efficiency, but more importantly, obtain a better wheel shape. The precision of the dressing device is high, and the feed rate should be up to the micron level. Excessive dressing affects both the quality of the grinding and the life of the grinding wheel.
2-4 cooling The correct choice of coolant type and cooling process parameters will often get twice the result with half the effort.
2-5 Grinding process parameter optimization Fully optimizing the grinding process parameters can balance the technical and economic indicators such as grinding efficiency, grinding quality and grinding cost at a higher level.
3, the application of CBN abrasive tools 3-1 domestic and international technology development overview With the advancement of industrial technology, high-speed, high-efficiency, high-precision grinding has become the mainstream of today's grinding technology development. CBN grinding is an advanced processing technology.
The development of CBN abrasive tool manufacturing and application technology has the following characteristics:
1 The application field has been continuously expanded. From the tool industry to the processing of difficult-to-wear metal materials, it has been extended to the processing of ordinary ferrous materials in the industries of bearings, automobiles, machine tools, compressors, etc. The grinding methods are also from general tool grinding and inner circle. Grinding, developed to slow-feed grinding, high-precision grinding, high-speed grinding, cam grinding, crankshaft grinding, and the potential to replace corundum grinding tools.
2 High speed, high efficiency, high quality and low cost are the main features. The speed of use is generally 80~125m/s; the large amount of coarse grinding is completed once; the surface life of the workpiece is increased by 20~30% due to the compressive stress on the surface of the workpiece; the comprehensive grinding cost can be reduced by more than 10%.
3 Domestically imported complete CBN grinding technology is growing rapidly.
4 The manufacturing and application technology of domestic CBN abrasive tools has entered a new stage of high level and rapid development, and has entered the mainstream market of automobile manufacturing. Some CBN abrasive tools are close to the level of similar foreign products and can replace imports.
5 domestic high-speed CNC CBN special grinding machine has been successfully developed.
3-2CBN Abrasives Application Example â—† Engine Camshaft Grinding
Example 1: Fine grinding automotive camshaft grinding wheel: 1A1180mmV125m/s Zhengzhou Abrasives Grinding Research Institute; Machine tool: Schott CF41CBN, Germany; Workpiece: cast iron, 8 cams, margin D1.0mm, Rmax3.2; Trimming: Diamond Roller, D180mm, trimming interval 200 pieces (800 cams), dressing diameter 5μm×3+3μm2/time; cooling: synthetic liquid, pressure 23bar; effect: reaching the level of imported grinding wheel, the overall cost is reduced by more than 30%.
Example 2: Precision grinding motorcycle camshaft grinding wheel: 1A1350mmV80m/s Zhengzhou Abrasives Grinding Research Institute; Machine tool: Japan Toyota Machine Cam Grinding Machine; Workpiece: 45# steel, 2 cams, HRc60, balance 0.2~0.3mm , Rz3.2, grinding efficiency 30S / root; trimming: diamond roller, trimming interval 240, trimming amount 0.002mm / time; effect: life can reach 80 ~ 90% of the imported grinding wheel, the cost is reduced by more than 30%.
Example 3: Rough grinding automobile camshaft grinding wheel: 1A1660mmV60m/s Zhengzhou Abrasives Grinding Research Institute; Machine tool: domestic MKS8312 cam grinder; workpiece: alloy cold-excited cast iron, 13 cams, HRc45, margin φ4mm, Ra2.5, Grinding efficiency 12 minutes / root; trimming: diamond cup roller, dressing interval 8 ~ 10 / time, dressing amount φ0.01x2; cooling: high efficiency grinding fluid, pressure 4kg, flow 120L / min; grinding wheel replacement cycle: 5000 Root / film; effect: instead of white corundum grinding wheel, the durability is increased by 100 times, the life is increased by 50 times, the production efficiency is increased by 10%, and the direct tool cost is reduced by 10%.
◆Automatic bearing inner diameter grinding example Grinding wheel: 1A810×15×3.5 V Zhengzhou Abrasives Grinding Research Institute Machine: Domestic MZ204 automatic internal grinding machine 24000rpm; Workpiece: 6201/02, GCr15, HRc61~65, balance 0.3~ 0.35mm, Ra0.8, grinding efficiency 25S/piece, feed rate 0.24mm/min (thick) and 0.17mm/min (fine); trimming: diamond pen, manual, trimming interval 200 pieces, dressing amount 0.02mm; Cooling: emulsion, concentrated supply; grinding wheel life: 2500 pieces (corundum grinding wheel 30 pieces / piece); effect: compared with white corundum grinding wheel, durability increased by 200 times, single piece production efficiency increased by about 40%, grinding wheel cost reduction 14%.
◆Filling refrigerator (air conditioning) compressor core assembly inner diameter example grinding wheel: 1A8 12×30×6, 1A125×20×13×3V 50m/s Zhengzhou Abrasives Grinding Research Machine: German Overbeck Company 400J-ELC-VA Round grinding machine, the maximum speed is 60000rpm; workpiece: base, cylinder (cover), HT20~40, FT20, HB170~223, HB70~90, machining allowance 0.2mm, Ra0.2~0.25, processing beat: 90~120 Piece/h. Trimming: Diamond roller, trimming interval 200~300 pieces, dressing amount 0.002mm/time; cooling: cooling oil with extreme pressure additive; grinding wheel life: 20000~2500 pieces/piece. Also available for thread grinding, high speed steel tool tooth and inner diameter grinding, compressor core assembly double face grinding, honing motorcycle cylinders and connecting rods, titanium alloy grinding, automotive insert inner diameter grinding, automotive steering inner diameter grinding Cutting and other application examples. I will not list them here.
â—†The hardness of CBN is much higher than other ordinary abrasives. High hardness means stronger cutting ability and sharper;
â—†CBN has high wear resistance, which means it is more difficult to wear than ordinary abrasives. The ability to maintain the shape of the abrasive particles is one of the main characteristics of CBN as a high performance abrasive;
â—†CBN has a high compressive strength, which means it can keep particles intact and not easy to break when used under harsh conditions;
â—†CBN has good thermal conductivity and can be cold cut during grinding. Due to the different properties of CBN and diamond, the range of materials they process varies. CBN is suitable for processing tools such as tool steel, bearing steel, alloy steel, super alloy, and cast iron. The materials suitable for processing diamond are cemented carbide, glass, ceramic, cermet, cast iron. 2. CBN Grinding System CBN Abrasives are a tool for bonding CBN abrasives together and forming a shape with different types of bonding agents. It can only maximize its function by relying on the reasonable grinding process and relying on the superior performance of the grinding machine. In the research and application of CBN grinding technology, CBN grinding tools, grinding machines, workpieces, dressing, cooling, grinding processes and other factors must be integrated into a system to optimize, in order to obtain the best technical and economic effects. Several important factors to consider in CBN grinding technology are as follows. 2-1CBN Abrasives mainly consider the shape, size, CBN abrasive particle size, concentration, binder type and speed of use when manufacturing and selecting abrasive tools.
â—†The shape, size and marking of CBN grinding tools are in accordance with GB/T6409.2-1996 and GB/T6409.1-1994 standards;
â—† Among the four binders (resin, metal, ceramic, electroplating) of CBN abrasives, ceramic binders are the fastest growing. This is because the ceramic CBN grinding tool has high grinding efficiency, good shape retention, high durability, easy dressing and long service life of the grinding wheel, thus becoming the first choice for efficient and high-precision grinding.
â—†The concentration of the grinding wheel indicates the number of abrasive grains involved in grinding on the working surface of the grinding wheel during grinding. High concentrations result in high grinding ratios and low workpiece surface roughness. For example, the 200% concentration is 4-5 times longer than the 100% concentration wheel.
â—† The hardness grade of the abrasive tool indicates the amount of bonding force to the abrasive. The uniformity and stability of the hardness of the grinding wheel and the reasonable choice of hardness are important prerequisites for ensuring the quality of the grinding. The 2-2 grinding machine is the center of the grinding system. The performance of the grinding machine has the most important effect on the grinding effect, especially for CBN grinding.
â—† Improve the working speed of the grinding wheel, which can significantly improve the grinding efficiency, grinding ratio and surface quality of the workpiece. The use speed of 80~125m/s has become one of the basic characteristics of CBN special camshaft grinding machines imported from China. Using high speeds as much as possible is an important prerequisite for improving the technical and economical aspects of CBN grinding.
â—†High-speed grinding and CBN grinding wheel grinding characteristics require high rigidity and good vibration resistance of the machine tool spindle and the whole. This is the basic requirement for the grinding machine in CBN high-speed grinding technology. Without such a condition, in the case of using a CBN grinding wheel, in order to obtain a higher metal removal amount, the geometric accuracy and surface quality of the workpiece are deteriorated. Ripple is a common surface quality defect that is produced by vibration. The cause of vibration is that the machine tool has low rigidity, poor vibration resistance or unreasonable design of the grinding wheel parameters, resulting in excessive grinding force.
2-3 dressing using diamond roller dressing can not only improve the dressing efficiency, but more importantly, obtain a better wheel shape. The precision of the dressing device is high, and the feed rate should be up to the micron level. Excessive dressing affects both the quality of the grinding and the life of the grinding wheel.
2-4 cooling The correct choice of coolant type and cooling process parameters will often get twice the result with half the effort.
2-5 Grinding process parameter optimization Fully optimizing the grinding process parameters can balance the technical and economic indicators such as grinding efficiency, grinding quality and grinding cost at a higher level.
3, the application of CBN abrasive tools 3-1 domestic and international technology development overview With the advancement of industrial technology, high-speed, high-efficiency, high-precision grinding has become the mainstream of today's grinding technology development. CBN grinding is an advanced processing technology.
The development of CBN abrasive tool manufacturing and application technology has the following characteristics:
1 The application field has been continuously expanded. From the tool industry to the processing of difficult-to-wear metal materials, it has been extended to the processing of ordinary ferrous materials in the industries of bearings, automobiles, machine tools, compressors, etc. The grinding methods are also from general tool grinding and inner circle. Grinding, developed to slow-feed grinding, high-precision grinding, high-speed grinding, cam grinding, crankshaft grinding, and the potential to replace corundum grinding tools.
2 High speed, high efficiency, high quality and low cost are the main features. The speed of use is generally 80~125m/s; the large amount of coarse grinding is completed once; the surface life of the workpiece is increased by 20~30% due to the compressive stress on the surface of the workpiece; the comprehensive grinding cost can be reduced by more than 10%.
3 Domestically imported complete CBN grinding technology is growing rapidly.
4 The manufacturing and application technology of domestic CBN abrasive tools has entered a new stage of high level and rapid development, and has entered the mainstream market of automobile manufacturing. Some CBN abrasive tools are close to the level of similar foreign products and can replace imports.
5 domestic high-speed CNC CBN special grinding machine has been successfully developed.
3-2CBN Abrasives Application Example â—† Engine Camshaft Grinding
Example 1: Fine grinding automotive camshaft grinding wheel: 1A1180mmV125m/s Zhengzhou Abrasives Grinding Research Institute; Machine tool: Schott CF41CBN, Germany; Workpiece: cast iron, 8 cams, margin D1.0mm, Rmax3.2; Trimming: Diamond Roller, D180mm, trimming interval 200 pieces (800 cams), dressing diameter 5μm×3+3μm2/time; cooling: synthetic liquid, pressure 23bar; effect: reaching the level of imported grinding wheel, the overall cost is reduced by more than 30%.
Example 2: Precision grinding motorcycle camshaft grinding wheel: 1A1350mmV80m/s Zhengzhou Abrasives Grinding Research Institute; Machine tool: Japan Toyota Machine Cam Grinding Machine; Workpiece: 45# steel, 2 cams, HRc60, balance 0.2~0.3mm , Rz3.2, grinding efficiency 30S / root; trimming: diamond roller, trimming interval 240, trimming amount 0.002mm / time; effect: life can reach 80 ~ 90% of the imported grinding wheel, the cost is reduced by more than 30%.
Example 3: Rough grinding automobile camshaft grinding wheel: 1A1660mmV60m/s Zhengzhou Abrasives Grinding Research Institute; Machine tool: domestic MKS8312 cam grinder; workpiece: alloy cold-excited cast iron, 13 cams, HRc45, margin φ4mm, Ra2.5, Grinding efficiency 12 minutes / root; trimming: diamond cup roller, dressing interval 8 ~ 10 / time, dressing amount φ0.01x2; cooling: high efficiency grinding fluid, pressure 4kg, flow 120L / min; grinding wheel replacement cycle: 5000 Root / film; effect: instead of white corundum grinding wheel, the durability is increased by 100 times, the life is increased by 50 times, the production efficiency is increased by 10%, and the direct tool cost is reduced by 10%.
◆Automatic bearing inner diameter grinding example Grinding wheel: 1A810×15×3.5 V Zhengzhou Abrasives Grinding Research Institute Machine: Domestic MZ204 automatic internal grinding machine 24000rpm; Workpiece: 6201/02, GCr15, HRc61~65, balance 0.3~ 0.35mm, Ra0.8, grinding efficiency 25S/piece, feed rate 0.24mm/min (thick) and 0.17mm/min (fine); trimming: diamond pen, manual, trimming interval 200 pieces, dressing amount 0.02mm; Cooling: emulsion, concentrated supply; grinding wheel life: 2500 pieces (corundum grinding wheel 30 pieces / piece); effect: compared with white corundum grinding wheel, durability increased by 200 times, single piece production efficiency increased by about 40%, grinding wheel cost reduction 14%.
◆Filling refrigerator (air conditioning) compressor core assembly inner diameter example grinding wheel: 1A8 12×30×6, 1A125×20×13×3V 50m/s Zhengzhou Abrasives Grinding Research Machine: German Overbeck Company 400J-ELC-VA Round grinding machine, the maximum speed is 60000rpm; workpiece: base, cylinder (cover), HT20~40, FT20, HB170~223, HB70~90, machining allowance 0.2mm, Ra0.2~0.25, processing beat: 90~120 Piece/h. Trimming: Diamond roller, trimming interval 200~300 pieces, dressing amount 0.002mm/time; cooling: cooling oil with extreme pressure additive; grinding wheel life: 20000~2500 pieces/piece. Also available for thread grinding, high speed steel tool tooth and inner diameter grinding, compressor core assembly double face grinding, honing motorcycle cylinders and connecting rods, titanium alloy grinding, automotive insert inner diameter grinding, automotive steering inner diameter grinding Cutting and other application examples. I will not list them here.
Household Storage & Organizers
Household Storage & Organizers,Storage Cabinet,Storage Drawers,Fabric Storage Bins
Changzhou Offistyle Furniture Co., Ltd. , https://www.offistyledesks.com