Composite CBN grinding wheel and preparation method thereof

Abstract

The invention belongs to the technical field of grinding wheel preparation, and mainly relates to a composite CBN grinding wheel and a preparation method thereof.The preparation method comprises the steps that firstly, according to the weight ratio, raw materials of a spherical grinding material, namely a CBN grinding material, carbon microspheres, a binding agent and a paste liquid are mixed; 2, atomizing and granulating the mixed solution, then sintering, and finally screening the sintered spherical abrasive to remove part of non-ball abrasive; thirdly, according to the weight ratio, raw materials of the composite CBN grinding wheel, namely the spherical grinding material, the binding agent and the paste liquid are mixed; and fourthly, a grinding wheel piece is formed through pressing, then sintering is conducted, and finally the grinding wheel piece adheres to the grinding wheel base body to form the grinding material layer. The carbon microspheres serve as a pore-forming agent, uniformly-distributed pores are formed through thermal decomposition or volatilization in the grinding wheel sintering process, and multiple improvement is achieved aiming at the high heat problem of end face grinding. A discontinuous cutting interface is formed on the surface of the grinding wheel through the holes, the actual contact area is reduced, and the friction heat generation amount is directly reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of grinding wheel preparation, and mainly relates to a composite CBN grinding wheel and a preparation method thereof. Background Art

[0002] Modern machining is developing towards high precision, high speed, hard machining, dry machining (without coolant), and cost reduction, etc., which puts quite high requirements on the performance of superhard abrasives. Currently, the commonly used superhard grinding materials include cubic boron nitride (CBN) and diamond abrasives. Although the hardness of CBN abrasive is inferior to that of diamond, its thermal stability and chemical stability are strong, especially it will not react with iron and iron alloys. Therefore, it has been widely used in the grinding of iron-based alloy materials such as hardened steel, high-speed tool steel, bearing steel, stainless steel, die steel, heat-resistant steel, advanced high-strength steel, high-chromium cast iron, as well as titanium alloy and nickel-based superalloy and other high-strength and tough difficult-to-machine materials.

[0003] With the development of technology, difficult-to-machine metals such as titanium alloy and superalloy (such as nickel-based superalloy, iron-based superalloy, and cobalt-based superalloy) have been widely used in high-end fields such as aeroengines due to their excellent high-temperature properties. However, the characteristics such as low thermal conductivity of these difficult-to-machine metals bring greater difficulties to their grinding processing. It not only requires higher grinding force, but also causes a very high grinding temperature. Excessive grinding heat will cause a very high residual stress in the workpiece and even burn the workpiece.

[0004] During face grinding, since the workpiece and the grinding wheel are in surface contact, the coolant cannot reach the grinding area in large quantities, which easily leads to burning of the ground workpiece. Summary of the Invention

[0005] The present invention provides a composite CBN grinding wheel and a preparation method thereof to solve the problem that when the CBN grinding wheel and the workpiece perform face grinding in the prior art, it is easy to cause burning of the ground workpiece.

[0006] To solve the above problems, the present invention adopts the following technical solutions: A composite CBN grinding wheel includes a grinding wheel base body and an abrasive layer. The abrasive layer is made of the following raw materials in parts by weight: 20 parts of spherical abrasive, 4 parts of binder, and 1 part of sizing solution. Among them, the spherical abrasive is made of the following raw materials in parts by weight: 10 parts of CBN abrasive, 2 parts of carbon microspheres, 1 part of binder, and 20 parts of sizing solution.

[0007] It has the following beneficial effects: The carbon microspheres are used as pore-forming agents, and uniformly distributed pores are formed through thermal decomposition or volatilization during the sintering process of the grinding wheel, achieving multiple improvements for the high heat problem of face grinding; The air or coolant within the pores forms a thermal insulation layer, reducing the heat conduction efficiency in the contact area between the grinding wheel and the workpiece and decreasing the heat transfer to the workpiece. The pores cause a "discontinuous cutting interface" to form on the surface of the grinding wheel, reducing the actual contact area and directly decreasing the amount of frictional heat generated.

[0008] Furthermore, the CBN abrasive is 400# or finer, the carbon microspheres are 20# - 120#, and the binder W40 is finer.

[0009] It has the following beneficial effects: The fine abrasive reduces the spacing between abrasive grains on the working surface of the grinding wheel, making the cutting trajectory finer and enabling a precision-machined surface. The micro-cutting action of the fine abrasive reduces the load borne by a single abrasive grain, decreases the fluctuation of the grinding force, and inhibits workpiece deformation and burning caused by local stress concentration.

[0010] Furthermore, the binder is a ceramic binder.

[0011] A method for preparing a composite CBN grinding wheel, used to prepare the described composite CBN grinding wheel, includes the following steps: Step 1: Mix the raw materials of the spherical abrasive: CBN abrasive, carbon microspheres, binder, and paste semen according to the weight ratio. Step 2: Atomize and granulate the mixed solution, then sinter it, and finally screen the sintered spherical abrasive to remove some of the non-spheroidized abrasive. Step 3: Mix the raw materials of the composite CBN grinding wheel: spherical abrasive, binder, and paste semen according to the weight ratio. Step 4: Press it into a grinding wheel disc, then sinter it, and finally bond it to the grinding wheel base to form an abrasive layer.

[0012] It has the following beneficial effects: The carbon microspheres, as pore-forming agents, form uniformly distributed pores through thermal decomposition or volatilization during the sintering process of the grinding wheel, achieving multiple improvements for the high heat problem in face grinding. The air or coolant within the pores forms a thermal insulation layer, reducing the heat conduction efficiency in the contact area between the grinding wheel and the workpiece and decreasing the heat transfer to the workpiece. The pores cause a "discontinuous cutting interface" to form on the surface of the grinding wheel, reducing the actual contact area and directly decreasing the amount of frictional heat generated.

[0013] Furthermore, in Step 1, the mixing of the raw materials of the spherical abrasive requires stirring for 10 minutes.

[0014] It has the following beneficial effects: The carbon microspheres have a micron-sized particle diameter and need to be fully stirred to avoid agglomeration. If the stirring time is insufficient, the carbon microspheres may form local aggregates, resulting in uneven pore sizes inside the sintered spherical abrasive (appearing "large pore clusters" or "pore-free regions"), affecting the uniformity of heat dissipation and chip accommodation.

[0015] Furthermore, in step 2, a peristaltic pump is used to feed materials in the atomization granulation, an atomizer is used to granulate, and a dryer is used to dry the granules of the atomizer.

[0016] It has the following beneficial effects: It adopts the combined process of peristaltic pump feeding + atomizer granulation + dryer drying, and systematically improves the pore uniformity, structural stability and production controllability of the spherical abrasive by precisely controlling the material conveying state, particle forming process and drying environment.

[0017] Furthermore, the peristaltic pump is 300 ml / min, the atomizer speed is 10000 r / min, and the dryer temperature is 150°C.

[0018] Furthermore, in step three, the raw materials of the composite CBN grinding wheel need to be mixed and stirred for 50 minutes.

[0019] Furthermore, a planetary mixer is used to mix and stir the raw materials of the composite CBN grinding wheel.

[0020] It has the following beneficial effects: ensuring the uniform distribution of carbon microspheres and binders at the nanometer to millimeter scale, laying the foundation for forming an efficient heat dissipation pore network after sintering.

[0021] Furthermore, in step 4, the mixed composite CBN grinding wheel raw material is weighed according to the required weight, and then put into a mold and pressed into a grinding wheel sheet on a press. DETAILED DESCRIPTION

[0022] A composite CBN grinding wheel comprises a grinding wheel matrix and an abrasive layer, wherein the abrasive layer is made of the following raw materials in parts by weight: 20 parts of spherical abrasive, 4 parts of W40 fine ceramic binder, and 1 part of dextrin liquid.

[0023] The spherical abrasive is made of the following raw materials in parts by weight: 10 parts of 400# fine CBN abrasive, 2 parts of 20#-120# carbon microspheres, 1 part of W40 fine ceramic binder, and 20 parts of dextrin liquid.

[0024] As a pore-forming agent, carbon microspheres form evenly distributed pores through thermal decomposition or volatilization during the sintering process of the grinding wheel, achieving multiple improvements for the high heat problem of end face grinding. The air or coolant in the pores forms a thermal insulation layer, which reduces the heat conduction efficiency of the contact area between the grinding wheel and the workpiece and reduces the heat transfer to the workpiece. The pore network provides a penetration path for the grinding fluid, allowing the coolant to directly reach the grinding interface and quickly take away the heat through convection heat transfer. The pores provide storage space for grinding debris, avoiding secondary grinding caused by debris accumulation and reducing additional heat generation. The pores form a "discontinuous cutting interface" on the surface of the grinding wheel, reducing the actual contact area and directly reducing the amount of friction heat generated.

[0025] During sintering, the carbon microspheres combine with CBN abrasive grains and ceramic bond to form a "grain - pore" composite structure. During the grinding process, the abrasive grains can expose new cutting edges in a timely manner, avoiding the sharp increase in grinding force and heat accumulation caused by grain dulling.

[0026] In this embodiment, the CBN abrasive grains, carbon microspheres, ceramic bond, and paste solution are mixed into spherical abrasives, forming nano - to micron - scale pore units inside each sphere to ensure the microscopic bonding uniformity between the pore - forming agent and the abrasive grains. The ceramic bond and paste solution on the outer layer of the spherical abrasive form a coating layer to prevent the carbon microspheres from falling off during subsequent processes, and at the same time provide a stable "porous abrasive unit" for secondary mixing.

[0027] The pre - fabricated spherical abrasives are mixed with ceramic bond and paste solution again, and the gaps between the spheres form macroscopic connected pores, constructing a "micro - macro dual - pore network" that takes into account both heat dissipation efficiency and wheel strength.

[0028] By adjusting the raw material ratios of the two - stage mixing, the porosity of the abrasive layer of the grinding wheel can be made higher, forming a gradient performance of "heat dissipation priority - structural support".

[0029] The self - sharpening property and pore friction - reducing effect of the spherical abrasives reduce the grinding force and generate less heat at the source. The dual - pore network dissipates the grinding heat through a dual mechanism of "pore air insulation + grinding fluid convection", reducing the workpiece surface temperature. The gradual consumption of carbon microspheres and the dynamic update of pores enable the grinding wheel to maintain stable heat dissipation performance during long - term grinding, avoiding heat dissipation failure caused by pore blockage.

[0030] In this embodiment, the particle size of 400# CBN abrasive grains is about 38μm. "Finer" means including finer particle sizes (such as 500#, 600#, with smaller particle sizes), forming a high - density micro - cutting edge group.

[0031] The finer abrasives reduce the spacing between abrasive grains on the working surface of the grinding wheel, making the cutting trajectories finer and enabling a precision - machined surface. The micro - cutting action of the finer abrasives reduces the load borne by a single abrasive grain, reduces the fluctuation of the grinding force, and inhibits workpiece deformation and burning caused by local stress concentration. The finer abrasives work in a mode of "mainly cutting and supplemented by plowing", reducing the plastic deformation heat caused by plowing and reducing heat generation at the source. The finer abrasives have a lower fracture threshold and are more likely to form new cutting edges after wear, shortening the self - sharpening cycle and avoiding the sharp increase in frictional heat caused by excessive grain dulling.

[0032] The particle size of 20# carbon microspheres is about 830μm, and that of 120# is about 125μm. The wide particle size range forms a cross - scale pore network, solving the performance limitations of pore formation with a single particle size.

[0033] Carbon microspheres with a particle size of 830 - 250 μm form millimeter-scale connected pores, and the chip-holding space is 2 - 3 times larger than that of a single fine-pore structure. This can quickly discharge large-sized chips generated by face grinding and avoid secondary grinding heat caused by chip accumulation. The large pores act as a "coolant reservoir", which can adsorb more grinding fluid, form a continuous cooling and lubricating film in the grinding contact area, and reduce the interfacial friction coefficient.

[0034] Carbon microspheres with a particle size of 125 - 180 μm are filled in the gaps between the coarse pores to form a "skeleton-filled" support structure, making the compressive strength of the grinding wheel higher than that of a single coarse-pore structure and avoiding the risk of grinding wheel breakage caused by large pores. The small-sized pores of the fine carbon microspheres can buffer the difference in thermal expansion coefficients between the CBN abrasive and the ceramic bond, reducing microcracks caused by thermal stress.

[0035] By controlling the mixing ratio of 20# - 120# carbon microspheres, a gradient structure with coarse pores on the surface layer (60% of 20# - 60#) and fine pores inside (70% of 80# - 120#) can be formed on the end face of the grinding wheel. Surface layer: The large pores come into contact with the workpiece first, strengthening cooling and chip removal. Inside: The fine pores maintain the structural strength and prevent the overall collapse of the grinding wheel.

[0036] W40 means that the maximum particle size of the ceramic bond micropowder is ≤40 μm, and "fine" includes finer particles such as W28 and W20, achieving nanoscale interfacial bonding.

[0037] The fine ceramic bond particles can be embedded in the nanoscale concave-convex structures on the surface of the CBN abrasive (such as the sharp edges generated by abrasive breakage). The bonding area is larger than that of the coarse ceramic bond, the holding strength is improved, and the fine abrasive is prevented from falling off under high loads. The diffusion path of the fine ceramic bond particles during high-temperature sintering is shorter, which can fill the nanoscale gaps between the abrasive and the carbon microspheres, forming a continuous glass phase or metal bond film and avoiding the "bridging" defect of the traditional coarse-grained bond.

[0038] The fine ceramic bond can uniformly coat carbon microspheres of different particle sizes, forming a "abrasive-ceramic bond-carbon microsphere" nanocomposite layer during the first mixing, preventing the agglomeration of carbon microspheres caused by coarse ceramic bond particles, and ensuring the uniformity of pore distribution. The sintering activation energy of the fine ceramic bond particles is higher, and they are not easily softened and lost at high grinding temperatures, maintaining the stability of the pore structure.

[0039] A preparation method of a composite CBN grinding wheel for preparing a composite CBN grinding wheel, comprising the following steps: Step 1: Mix and stir the raw materials of the spherical abrasive: CBN abrasive, carbon microspheres, ceramic bond, and paste semen in a weight ratio for 10 minutes.

[0040] After the carbon microspheres are mixed and granulated with CBN abrasives, micron-scale pores are formed inside each spherical abrasive. These pores can serve as micro liquid storage cavities during grinding, adsorbing the coolant and vaporizing and absorbing heat under the action of grinding heat, directly reducing the temperature in the contact area between the abrasive and the workpiece.

[0041] The CBN abrasives, carbon microspheres, ceramic bond, etc. are made into spherical abrasives, enabling a single abrasive grain to have an independent pore structure. Compared with traditional bulk abrasives, the regular geometric shape of the spherical abrasives can reduce sliding friction during grinding and lower frictional heat. At the same time, the point contact state between the spherical particles increases the overall porosity of the grinding wheel, significantly improving air permeability and coolant permeability.

[0042] Step 2: Atomize and granulate the mixed solution, then sinter it, and finally screen the sintered spherical abrasives to remove some unformed abrasives.

[0043] Step 3: According to the weight ratio, mix and stir the raw materials of the composite CBN grinding wheel: spherical abrasives, ceramic bond, and sizing solution, using a planetary mixer for 50 minutes.

[0044] When the spherical abrasives and the ceramic bond are mixed and pressed, the gaps between the spherical abrasives form sub-millimeter-level connected pores, constituting an efficient chip removal channel. During grinding, the chips can be quickly discharged through these pores, avoiding secondary grinding heat generation caused by chip retention. At the same time, it provides a flow path for the coolant, strengthening convective heat dissipation.

[0045] The spherical abrasives and the ceramic bond are mixed for the second time, and a "rigid skeleton + porous network" composite structure is formed through pressing and sintering. The spherical abrasives serve as the load-bearing body, providing the hardness and strength required for grinding. When the ceramic bond fills the gaps between the spherical abrasives, the remaining connected pores form a three-dimensional heat dissipation channel, enabling the grinding heat to be quickly dissipated through multiple mechanisms such as air convection in the pores, coolant evaporation, and chip discharge.

[0046] Step 4: Weigh the mixed raw materials of the composite CBN grinding wheel according to the required weight, then put them into a mold, press them into a grinding wheel disc on a press, then sinter them, and finally bond them to the grinding wheel base to form an abrasive layer.

[0047] As the grinding process progresses, the abrasives on the surface of the grinding wheel wear, and the new abrasives containing pores inside are continuously exposed. At this time, the pore structure formed by the carbon microspheres not only continuously provides chip accommodation and cooling capabilities but also promotes the micro-crushing of the abrasives through the stress concentration effect between the pores, achieving a "self-sharpening" effect and reducing the accumulation of frictional heat caused by abrasive passivation.

[0048] The pore network formed by creating pores in carbon microspheres can improve the grinding heat conduction efficiency. At the same time, the coolant can directly reach the grinding interface through the pores, achieving "precision cooling in the contact area" and avoiding the problem that the coolant is difficult to penetrate into the contact area during traditional external pouring. The multi-level pore structure expands the chip storage space of the grinding wheel. Combined with the rolling grinding characteristics of spherical abrasives, it can significantly reduce the risk of chip clogging and avoid the increase in grinding force and heat generation caused by chip accumulation. The low friction characteristics of spherical abrasives can reduce the grinding force. Combined with the heat dissipation effect of the pore structure, it forms a virtuous cycle of "low heat generation + fast heat dissipation", eliminating the thermodynamic conditions for workpiece burn from the root cause.

[0049] This preparation method constructs a multi-level pore structure by creating pores in carbon microspheres and forms a composite grinding tool structure through two mixings, systematically solving the core problems of "difficult heat dissipation, poor chip accommodation, and high frictional heat" in face grinding. Through the thermal management functions of the pores (heat dissipation, liquid storage, chip removal) and the mechanical optimization of spherical abrasives (low friction, self-sharpening), the thermal balance control of the grinding process is achieved.

[0050] In Step 1, the mixing and stirring time of the raw materials of the spherical abrasive is clearly set to 10 minutes. Through 10 minutes of stirring, the material dispersion uniformity is optimized and the granulation precursor state is controlled, laying a key foundation for the subsequent pore creation effect, abrasive performance, and the overall quality of the grinding wheel.

[0051] In this embodiment, the raw materials of the spherical abrasive include CBN abrasive (hard particles), carbon microspheres (pore-forming agent), ceramic binder (adhesive phase), and sizing solution (solvent / formulating aid), and their physical properties are significantly different (such as density, particle size, surface polarity).

[0052] The particle size of the carbon microspheres is in the micron range, and sufficient stirring is required to avoid agglomeration. If the stirring time is insufficient, the carbon microspheres may form local aggregates, resulting in uneven pore sizes inside the sintered spherical abrasive (appearing "large pore clusters" or "pore-free regions"), affecting the uniformity of heat dissipation and chip accommodation. Stirring for 10 minutes can improve the dispersion of the carbon microspheres, ensure a reduced deviation in the porosity of each spherical abrasive, and avoid grinding hot spots caused by local pore loss.

[0053] The ceramic binder needs to be evenly adsorbed on the surface of the CBN abrasive to form "abrasive-binder" composite particles. Insufficient stirring time will result in incomplete coating of the ceramic binder, causing the abrasive to separate from the carbon microspheres during granulation, forming "hollow balls" or "debris aggregates". After sintering, the ceramic binder cannot effectively bond the abrasive and the carbon microspheres, resulting in insufficient strength of the spherical abrasive and easy fracture and failure during the grinding process. Through 10 minutes of stirring, by extending the shear action time, the ceramic binder can completely wet the surface of the CBN abrasive, forming a uniformly thick coating layer to ensure a dense structure of the composite particles after granulation.

[0054] Through stirring, the raw materials are evenly mixed: the carbon microspheres volatilize synchronously to form pores with consistent pore sizes; the ceramic binder melts evenly, fills the gaps between abrasives and forms a stable skeleton, avoiding sintering cracks or pore collapse caused by local composition segregation. When the spherical abrasives with uniform particle sizes and dense structures are secondarily mixed, they have a higher filling efficiency with the ceramic binder, and a regular packing structure can be formed during pressing, avoiding uneven density of the grinding wheel due to differences in the particle sizes of the spherical abrasives or internal defects.

[0055] In step two, a peristaltic pump is used for feeding during atomization granulation, an atomizer is used for granulation, and a dryer is used to dry the granulation of the atomizer. In this embodiment, the peristaltic pump is 300 ml / min, the rotation speed of the atomizer is 10,000 r / min, and the temperature of the dryer is 150 °C.

[0056] Adopting a combined process of peristaltic pump feeding + atomizer granulation + dryer drying, through precise control of the material transportation state, particle forming process and drying environment, the pore uniformity, structural stability and production controllability of the spherical abrasives are systematically improved.

[0057] As a pore-forming agent, the original particle size and integrity of the carbon microspheres directly determine the initial morphology of the pores in the grinding wheel. The peristaltic pump conveys materials by peristaltic extrusion through a flexible hose and has the characteristic of low shear force. During the transportation process through the peristaltic pump, the carbon microspheres have a high particle size retention rate. The polymer chains in the paste semen are not broken, maintaining the viscosity stability of the system and ensuring regular droplet formation during subsequent atomization granulation.

[0058] The atomizer disperses the mixed liquid into uniform droplets by high-speed shear or centrifugal force. By adjusting the atomization centrifugal rotation speed, the droplet particle size can be precisely controlled.

[0059] The peristaltic pump ensures that the carbon microspheres are not damaged, the atomizer evenly distributes the carbon microspheres in the droplets, the dryer fixes their positions, and the carbon microspheres volatilize synchronously during sintering to form a uniform pore network with a small pore size deviation, greatly improving the chip holding and heat dissipation efficiency of the grinding wheel. The uniform pores can improve the permeability of the coolant in the grinding area. At the same time, the regular packing of the spherical abrasives reduces the grinding contact area, and the grinding temperature is reduced under the dual action, directly reducing the risk of workpiece burn.

[0060] In this embodiment, under the dual movement of self-rotation + revolution of the stirring paddle of the planetary mixer, a complex material flow trajectory can be formed. Radial convection: The paddle blades push the material to reciprocate along the radius direction of the mixing barrel, breaking the accumulation barrier of the spherical abrasive. Axial surging: The gap between the edge of the paddle blade and the barrel wall forces the material to rise and fall along the barrel wall, eliminating the "stagnant layer" at the top and the "sedimentation layer" at the bottom. Shearing and dispersion: The relative movement between the paddle blade and the material generates a shearing force, which can effectively disperse the ceramic binder aggregates and at the same time evenly coat the surface of the spherical abrasive with the paste semen. The planetary mixer ensures the uniform distribution of carbon microspheres and ceramic binders at the nano-to-millimeter scale, laying a foundation for the formation of an efficient heat dissipation pore network after sintering.

[0061] Using the micro-powder granulation process, the CBN abrasive is made into spherical abrasive, and then the made spherical abrasive is used as raw material to make a ceramic CBN grinding wheel. After the grinding wheel is made, the internal pores are evenly distributed, providing sufficient cooling space for the grinding process of the grinding wheel. And each spherical abrasive is composed of numerous CBN abrasives. During the use of the grinding wheel, after the abrasive edge is passivated, the micro-powder abrasive can fall off in time, exposing a new edge and maintaining good grinding performance of the grinding wheel. At the same time, a large amount of ceramic binder is added during the secondary sintering, providing a strong connection force for each spherical abrasive and ensuring the overall strength of the grinding wheel. In the grinding state of this method, the grinding wheel is continuously self-sharpening and always maintains a good grinding edge, so that during the entire grinding process, the grinding wheel does not need to be dressed and continuous grinding can be realized.

[0062] Case study Data analysis of each item of the grinding wheel for bearing end face grinding

[0063] Processing cycle of traditional ceramic CBN grinding wheel: 24 seconds, requires roller dressing, 600 pieces / dressing.

[0064] Processing cycle of the composite CBN grinding wheel in this embodiment: 23 seconds, no roller dressing.

[0065] From the above data, it can be seen that the composite CBN grinding wheel in this embodiment has the following three advantages: ① The composite CBN grinding wheel is much higher than the traditional ceramic CBN grinding wheel in terms of use stability and service life.

[0066] ② During the use process, the composite CBN grinding wheel does not require roller dressing, so the use cost of the roller is directly saved.

[0067] ③ The processing cycle is saved by 1 second, 30 minutes are saved for each cycle without dressing, about 4 seconds are saved per piece, and the overall production efficiency is improved by 14.8% in general evaluation.

Claims

1. A composite CBN grinding wheel, comprising a grinding wheel base body and an abrasive layer, characterized in that, The abrasive layer is made of the following raw materials in parts by weight: 20 parts of spherical abrasive, 4 parts of binder, and 1 part of sizing agent solution. Among them, the spherical abrasive is made of the following raw materials in parts by weight: 10 parts of CBN abrasive, 2 parts of carbon microspheres, 1 part of binder, and 20 parts of sizing agent solution.

2. The composite CBN grinding wheel according to claim 1, wherein The CBN abrasive is finer than 400#, the carbon microspheres are 20# - 120#, and the binder is finer than W40.

3. The composite CBN grinding wheel according to claim 1, characterized in that, The binder is a ceramic binder.

4. A preparation method of a composite CBN grinding wheel, characterized in that, For preparing the composite CBN grinding wheel according to any one of claims 1 - 3, it includes the following steps: Step 1: Mix the raw materials of the spherical abrasive: CBN abrasive, carbon microspheres, binder, and sizing agent solution according to the weight ratio. Step 2: Atomize and granulate the mixed solution, then sinter it, and finally screen the sintered spherical abrasive to remove some unformed abrasive. Step 3: Mix the raw materials of the composite CBN grinding wheel: spherical abrasive, binder, and sizing agent solution according to the weight ratio. Step 4: Press it into a grinding wheel sheet, then sinter it, and finally bond it to the grinding wheel base to form an abrasive layer.

5. The preparation method of the composite CBN grinding wheel according to claim 4, characterized in that, In Step 1, the mixing of the raw materials of the spherical abrasive needs to be stirred for 10 minutes.

6. The preparation method of the composite CBN grinding wheel according to claim 4, wherein, In Step 2, a peristaltic pump is used for feeding during atomization granulation, an atomizer is used for granulation, and a dryer is used to dry the granulation of the atomizer.

7. The preparation method of the composite CBN grinding wheel according to claim 6, characterized in that, The peristaltic pump is 300 ml / min, the atomizer rotation speed is 10,000 r / min, and the dryer temperature is 150°C.

8. The preparation method of the composite CBN grinding wheel according to claim 4, characterized in that, In Step 3, the mixing of the raw materials of the composite CBN grinding wheel needs to be stirred for 50 minutes.

9. The preparation method of the composite CBN grinding wheel according to claim 8, characterized in that, A planetary mixer is used for mixing and stirring the raw materials of the composite CBN grinding wheel.

10. The preparation method of the composite CBN grinding wheel according to claim 4, characterized in that, In Step 4, weigh the mixed raw materials of the composite CBN grinding wheel according to the required weight, then put them into a mold and press them into a grinding wheel sheet on a press.

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