阅读说明：本技术 一种纳米陶瓷结合剂cBN气孔砂轮及其制备方法 (Nano ceramic bond cBN pore grinding wheel and preparation method thereof ) 是由 刘振波 于 2021-09-30 设计创作，主要内容包括：本发明公开了一种纳米陶瓷结合剂cBN气孔砂轮及其制备方法,将cBN磨料、填料、无机组合物及亚克力微球加入丙酮或者酒精等溶液中,混合、干燥后得到陶瓷粉料；然后将陶瓷粉料填充至金属模具后冷压压平,最后将金属模具置于热压机腔内保压后得到陶瓷素坯；然后将砂轮素坯烧结,得到纳米陶瓷结合剂cBN气孔砂轮。本发明创造性地在砂轮制备中使用亚克力微球进行造孔并通过热压固化工艺解决砂轮变形、开裂等问题,烧结后制得的砂轮锥度小、气孔孔径尺寸一致、分布均匀；本发明制备纳米陶瓷cbn气孔砂轮的方法未见近似报道。(The invention discloses a nanometer ceramic bond cBN air hole grinding wheel and a preparation method thereof, which comprises the steps of adding cBN abrasive, filler, inorganic composition and acrylic microspheres into solutions of acetone or alcohol and the like, mixing and drying to obtain ceramic powder; then filling ceramic powder into a metal mould, then carrying out cold pressing and flattening, and finally placing the metal mould in a hot press cavity for pressure maintaining to obtain a ceramic biscuit; and sintering the grinding wheel biscuit to obtain the nano ceramic bond cBN pore grinding wheel. According to the invention, acrylic microspheres are creatively used for pore forming in the preparation of the grinding wheel, the problems of deformation, cracking and the like of the grinding wheel are solved through a hot-pressing curing process, and the grinding wheel prepared after sintering has small taper, consistent pore diameter and uniform distribution; the method for preparing the nano ceramic cbn pore grinding wheel is not approximately reported.)

1. A nanometer ceramic bond cBN pore grinding wheel is characterized in that the grinding wheel is prepared from cBN abrasive, filler, inorganic composition and polymer resin balls; the inorganic composition includes silica, boron oxide, sodium oxide, and zinc oxide.

2. The nano-ceramic bond cBN porous grinding wheel according to claim 1, wherein the total weight of the cBN abrasive, the filler, the inorganic composition and the polymer resin balls is 100%, the weight of the cBN abrasive is 60 to 75wt%, the weight of the filler is 1 to 10wt%, the weight of the polymer resin balls is 2 to 8wt%, and the balance is the inorganic composition.

3. The nano-ceramic bond cBN pore grinding wheel as claimed in claim 1, wherein the inorganic composition is composed of silica, boron oxide, sodium oxide and zinc oxide; the filler is alumina, silicon carbide or glass beads; the polymer resin ball is an acrylic microsphere.

4. The nano-ceramic bond cBN pore grinding wheel as claimed in claim 3, wherein the inorganic composition comprises, by weight, 65% to 75% of silica, 10% to 25% of boron oxide, 2% to 5% of sodium oxide, and the balance zinc oxide.

5. The use of a nano-ceramic bonded cBN gas hole grinding wheel as defined in claim 1 in the machining of an inner bore of a bearing ring.

6. The method for manufacturing a nano-ceramic bond cBN pore grinding wheel as claimed in claim 1, which is characterized by comprising the following steps: mixing the cBN abrasive, the filler, the inorganic composition and the polymer resin balls to obtain ceramic powder; and the ceramic powder is sequentially subjected to cold pressing, hot pressing and sintering to obtain the nano ceramic bonding agent cBN pore grinding wheel.

7. The method for manufacturing a nano-ceramic bond cBN pore grinding wheel according to claim 6, wherein the cBN abrasive, the filler, the inorganic composition and the polymer resin balls are added into a solvent, and the solvent is removed after mixing to obtain ceramic powder; the hot pressing temperature is 150-180 ℃, the time is 10-30 min, and the pressure is 80-180 KN; sintering is carried out by raising the temperature to 800-960 ℃ in a sectional mode and preserving the temperature for 2-3 h.

8. The method for manufacturing a nano-ceramic bond cBN porous grinding wheel according to claim 7, wherein the solvent is acetone or alcohol; and removing the solvent by rotary evaporation to obtain the ceramic powder.

9. The method for manufacturing a nano-ceramic bond cBN pore grinding wheel according to claim 6, wherein the inorganic composition is composed of silica, boron oxide, sodium oxide and zinc oxide; the filler is alumina, silicon carbide or glass beads; the polymer resin ball is an acrylic microsphere.

The use of a cBN grinding material, a filler, an inorganic composition and a polymeric resin ball in the preparation of the nano-ceramic bond cBN porous grinding wheel as defined in claim 1, wherein the inorganic composition is composed of silica, boron oxide, sodium oxide and zinc oxide; the filler is alumina, silicon carbide or glass beads; the polymer resin ball is an acrylic microsphere.

Technical Field

The invention belongs to the technical field of preparation of ceramic cBN grinding wheels, and particularly relates to a nano ceramic bonding agent cBN pore grinding wheel and a preparation method thereof, which can be used for processing an inner hole of a bearing ring.

Background

Modern machining techniques are accelerating the development towards high-speed, high-efficiency and high-precision machining. Among the elements of the processing technology, the high-performance grinding tool is the key and guarantee for realizing high-speed, high-efficiency and high-precision processing. The cubic boron nitride has high hardness and high light degree, so that the grinding tool made of the cubic boron nitride has strong grinding capacity, high grinding efficiency, small abrasion of the grinding tool, good shape retentivity and long service life, and therefore, the cubic boron nitride has great advantages in grinding.

And practice proves that: if the grinding speed is increased from 35 to 50-60 percent, the general production efficiency can be improved by 30-60 percent, the durability of the grinding wheel is improved by about 0.7-1 time, and the rough rubbing parameter value of the surface of the workpiece is reduced by about 50 percent. At present, most of domestic bearing manufacturers adopt common grinding wheels such as corundum and microcrystalline corundum, a series of problems of low processing efficiency, frequent trimming, low stability of the quality of processed workpieces and the like exist, the development process of high-end bearing is severely limited, if a cBN grinding tool can be used through transformation and introduction, on one hand, the processing quality of the workpieces can be improved, the stability of products can be guaranteed, on the other hand, the feeding speed during grinding and processing can be greatly increased, the production efficiency can be improved, and the dust influence caused by the abrasion of the grinding wheel when the common grinding tool is used can be avoided.

Disclosure of Invention

The invention aims to provide a method and a product for preparing a nanometer ceramic bond cBN pore grinding wheel, the pore diameter of the prepared cBN grinding wheel blank after sintering is approximate in size and uniform in distribution, the taper is less than 0.1mm, and the grinding wheel can be widely used for high-speed grinding of an inner hole of a bearing ferrule piece.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

a nanometer ceramic bond cBN pore grinding wheel is prepared from cBN abrasive, filler, inorganic composition and polymer resin balls; the cBN abrasive, the filler, the inorganic composition and the polymer resin balls are 100 wt%, the cBN abrasive is 60-75 wt%, the filler is 1-10 wt%, the polymer resin balls are 2-8 wt%, and the balance is the inorganic composition, preferably, the cBN abrasive is 65-72 wt%, the filler is 4-7 wt%, the polymer resin balls are 3-6 wt%, and the balance is the inorganic composition.

In the present invention, the inorganic composition includes silica, boron oxide, sodium oxide, and zinc oxide; preferably, the inorganic composition consists of silica, boron oxide, sodium oxide and zinc oxide; in the inorganic composition, the weight percentage of each component is 65-75 percent of silicon dioxide, 10-25 percent of boron oxide, 2-5 percent of sodium oxide and the balance of zinc oxide; the filler can be alumina, silicon carbide, glass beads and the like; the polymer resin ball is an acrylic microsphere, namely a PMMA microsphere.

The invention discloses application of the nano ceramic bond cBN pore grinding wheel in processing an inner hole of a bearing ring. The nanometer ceramic bond cBN pore grinding wheel disclosed by the invention is used for bearing processing, on one hand, the processing quality of workpieces can be improved, the stability of products is guaranteed, on the other hand, the feeding speed in grinding processing can be greatly increased, the production efficiency is improved, and the influence of dust caused by the abrasion of the grinding wheel when the existing grinding tool is used is avoided.

The invention discloses a preparation method of the nanometer ceramic bond cBN pore grinding wheel, which comprises the following steps: mixing the cBN abrasive, the filler, the inorganic composition and the polymer resin balls to obtain ceramic powder; and the ceramic powder is sequentially subjected to cold pressing, hot pressing and sintering to obtain the nano ceramic bonding agent cBN pore grinding wheel.

In the invention, the cBN abrasive, the filler, the inorganic composition and the polymer resin ball are added into a solvent, and the solvent is removed after mixing to obtain ceramic powder; the hot pressing temperature is 150-180 ℃, the time is 10-30 min, and the pressure is 80-180 KN; the sintering is carried out by raising the temperature to 800-960 ℃ in a sectional mode, preserving the heat for 2-3 hours, for example, under the atmosphere of air, raising the temperature from room temperature to 450-550 ℃ for 2-3.5 hours, preserving the heat for 2.5-3.5 hours, raising the temperature to 650-750 ℃ for 2-3.5 hours, preserving the heat for 2-2.5 hours, raising the temperature to 800-960 ℃ for 2-3.5 hours, preserving the heat for 2-3 hours, and finally cooling along with the furnace.

In the invention, the solvent is acetone, alcohol and the like; removing the solvent by rotary evaporation to obtain ceramic powder; then filling the ceramic powder into a metal mould, then performing cold pressing and flattening, and then placing the metal mould into a hot press cavity for pressure maintaining to obtain a ceramic biscuit; and finally sintering the grinding wheel biscuit to obtain the nano ceramic cBN pore grinding wheel. Furthermore, the time of rotary evaporation is 30-45 minutes, the temperature is 60-80 ℃, and the vacuum degree is-0.090-0.15 MPa.

In the invention, the grain size of the cBN abrasive is micron-sized, such as 40-100 microns; the particle size of the filler is 50-100 microns; the particle size of the inorganic composition is 10-50 nanometers, such as 10-20 nanometers; the particle size of the polymer resin ball is 1-50 microns, such as 5-15 microns. The raw materials are all conventional raw materials for preparing grinding wheels in the field.

Compared with the prior art, the invention has the following advantages:

the grinding wheel has a proper amount of air holes, so that the grinding wheel can play a good role in cooling, accommodating scraps, removing chips and promoting the self-sharpening of the grinding wheel in the grinding process. The invention overcomes the prejudice of the prior art, and the nano ceramic cBN pore grinding wheel uses PMMA balls for the first time to form pores, has stable preparation method and has no relevant report at home and abroad. The nano ceramic cBN pore grinding wheel prepared by reasonably using the PMMA balls has higher use value, and the consistency and the distribution uniformity of the pore size are far larger than those of the cBN grinding wheel prepared by adding other pore-forming agents.

The grinding wheel prepared by the method has potential environmental protection value, can be used for replacing a common grinding wheel for processing the inner hole of the bearing ring, and greatly reduces the generation of dust in grinding. The raw materials involved in the invention are all commercial products, such as alumina microspheres, existing products, available in the market and in accordance with national standards.

Drawings

FIG. 1 is a photomicrograph of a nano-ceramic cBN pore grinding wheel according to an embodiment of the invention;

FIG. 2 is a photomicrograph of a grinding wheel using polystyrene microsphere pore formers;

FIG. 3 is a diagram showing the effect of the nano ceramic air hole grinding wheel after processing a workpiece according to the present invention;

fig. 4 is a diagram showing the effect of a conventional commercially available grinding wheel after machining the same workpiece on the same equipment.

Detailed Description

The invention discloses a preparation method of a nanometer ceramic bond cBN pore grinding wheel, which comprises the following steps: adding the cBN abrasive, the auxiliary filler, the acrylic microspheres and the inorganic composition into a solvent, and performing rotary evaporation to obtain ceramic powder; then filling the ceramic powder into a metal mold for cold pressing and flattening, and finally placing the metal mold into a hot press cavity for pressure maintaining and then demoulding to obtain a ceramic biscuit; and sintering the grinding wheel biscuit to obtain the nano ceramic cBN pore grinding wheel. According to the invention, through the selection of the formula, the obtained nano ceramic cBN pore grinding wheel has uniform pore distribution and consistent size, the deformation of the grinding wheel after sintering is small, and the taper is less than or equal to 0.1mm, the nano ceramic cBN pore grinding wheel prepared by the nano ceramic cBN pore grinding wheel has higher use value, and the sharpness and the stability of the nano ceramic cBN pore grinding wheel are far greater than those of the existing common abrasive grinding wheel for processing the inner hole of the bearing ring.

The grinding wheel machining and workpiece machining related to the invention are carried out according to the existing method, and the performance characterization of the grinding wheel, such as taper, pore distribution, pore diameter and porosity (Archimedes drainage method) testing methods are conventional methods in the field. The cBN grit has a micron size, such as 70 microns; the particle size of the filler is 80 microns; the particle size of the inorganic composition is 15 nanometers; the grain diameter of the acrylic microsphere is 10 microns.

Example one

Weighing 50g of cBN abrasive, 3.6g of filler SiC, 3.6g of acrylic microspheres and 14.3g of inorganic composition, conventionally mixing the inorganic composition by taking alcohol as a solvent, placing the mixture in a rotary evaporator, rotationally evaporating the mixture for 25min at 60 ℃ and under-0.12 Mpa, then filling the ceramic powder into the existing metal mold, conventionally cold-pressing and flattening the ceramic powder, then placing the metal mold in a 170 ℃ hot press cavity, preserving the heat for 30min by 120KN, and then demolding to obtain a cBN grinding wheel biscuit; placing the taken grinding wheel biscuit in a high-temperature resistance furnace for sectional type temperature rise sintering, and finally cooling along with the furnace to obtain a nano ceramic air hole grinding wheel for processing an inner hole of a bearing ring, wherein the outer diameter of the grinding wheel is 47mm, the inner hole is 38mm, and the height is 24 mm; the inorganic composition comprises 73% of silicon dioxide, 20% of boron oxide, 3% of sodium oxide and the balance of zinc oxide by weight; the sintering is carried out in an air atmosphere, the sintering process is that the temperature is increased from room temperature to 500 ℃ for 3 hours, the temperature is maintained for 3 hours, then the temperature is increased from 500 ℃ to 700 ℃ for 3 hours, the temperature is maintained for 2 hours, then the temperature is increased from 700 ℃ to 930 ℃ for 3 hours, the temperature is maintained for 2 hours, and finally the furnace cooling is carried out. FIG. 1 is a photomicrograph of the nano ceramic pore grinding wheel, which shows that the pores of the grinding wheel prepared by the invention are regular and uniformly distributed.

On the basis of the first embodiment, the acrylic resin spheres are replaced by polystyrene microspheres with the same size, and the rest are unchanged to obtain the nano ceramic air hole grinding wheel, wherein a micrograph is shown in fig. 2, and the air hole regularity and the distribution uniformity are poor.

The inner hole of the bearing ring is processed by adopting the existing equipment by taking the prior commercially available grinding wheel (the outer diameter of the grinding wheel is 47mm, the inner hole is 38mm, the height is 24mm, and the grinding wheel is one of the grinding wheels with good industrial application effect at present) for comparison, and the following table shows that the inner hole of the bearing ring is compared with the parameters of part of the processing performance of the prior commercially available grinding wheel and the nano ceramic air hole grinding wheel of the invention:

fig. 3 and 4 are respectively the effect diagrams of the nano ceramic pore grinding wheel and the prior commercially available grinding wheel after processing the same workpiece on the same equipment, and it can be seen that the grinding lines on the surface of the workpiece processed by the grinding wheel are very fine and regular.

Example two

37g of cBN abrasive, 1.15g of filler alumina, 2.3g of acrylic microspheres and 9.2g of inorganic composition are weighed; adding the ceramic powder into an alcohol solution, mixing, placing in a rotary evaporator, rotationally evaporating at 80-0.09 Mpa for 30min to obtain ceramic powder, filling the ceramic powder into a metal mold with a mold release agent sprayed on the surface, cold-pressing and flattening, finally placing the metal mold in a hot press cavity with the temperature of 180 ℃, keeping the temperature for 15min by 100KN, and demolding to obtain a cBN grinding wheel biscuit; placing the taken grinding wheel biscuit in a high-temperature resistance furnace to perform sectional type temperature rise sintering on the grinding wheel biscuit, keeping the temperature for 3h at the highest temperature of 960 ℃, and finally cooling along with the furnace to obtain a nano ceramic air hole grinding wheel which is used for processing an inner hole of a bearing ring, wherein the outer diameter of the grinding wheel is 36mm, the inner hole is 27mm, and the height is 33 mm; the inorganic composition comprises 68% of silicon dioxide, 25% of boron oxide, 4% of sodium oxide and the balance of zinc oxide; the sintering is carried out in an air atmosphere, the sintering process is that the temperature is increased from room temperature to 500 ℃ for 3 hours, the temperature is maintained for 3 hours, then the temperature is increased from 500 ℃ to 700 ℃ for 3 hours, the temperature is maintained for 2 hours, then the temperature is increased from 700 ℃ to 960 ℃ for 3 hours, the temperature is maintained for 3 hours, and finally the furnace cooling is carried out.

EXAMPLE III

28g of cBN abrasive, 4.6g of SiC, 2.8g of acrylic microspheres and 11.2g of inorganic composition are weighed; adding the mixture into an alcohol solution, mixing, placing the mixture into a rotary evaporator, rotationally evaporating the mixture at 70 ℃ and 0.15Mpa for 40min to obtain ceramic powder, filling the ceramic powder into a metal mold with a mold release agent sprayed on the surface, performing cold pressing and flattening, finally placing the metal mold into a hot press cavity with the temperature of 160 ℃, performing heat preservation for 30min by 150KN, and demolding to obtain a cBN grinding wheel biscuit; placing the taken grinding wheel biscuit in a high-temperature resistance furnace to perform sectional type temperature rise sintering on the grinding wheel biscuit, keeping the temperature for 2 hours at the highest temperature of 930 ℃, and finally cooling along with the furnace to obtain a nano ceramic air hole grinding wheel which is used for processing an inner hole of a bearing ring, wherein the outer diameter of the grinding wheel is 28mm, the inner hole is 23mm, and the height is 23 mm; the inorganic composition comprises 73% of silicon dioxide, 20% of boron oxide, 3% of sodium oxide and the balance of zinc oxide; the sintering is carried out in an air atmosphere, the sintering process is that the temperature is increased from room temperature to 500 ℃ for 3 hours, the temperature is maintained for 3 hours, then the temperature is increased from 500 ℃ to 700 ℃ for 3 hours, the temperature is maintained for 2 hours, then the temperature is increased from 700 ℃ to 930 ℃ for 3 hours, the temperature is maintained for 2 hours, and finally the furnace cooling is carried out.

Comparative example 1

On the basis of the first embodiment, the rotary evaporation process is replaced by forced air drying, namely, the rotary evaporation process is placed in a forced air drying oven and dried for 30min at the temperature of 60 ℃ to obtain ceramic powder; the rest is unchanged, and the grinding wheel with the taper of 0.39mm is obtained.

Comparative example No. two

A grinding wheel was obtained by replacing sodium oxide with calcium oxide and leaving the same in example one, and subjected to a machining test similar to that of example one at a feed rate of 80 μm/s.

On the basis of example one, the zinc oxide was replaced with potassium oxide, and the remainder was unchanged to obtain a grinding wheel, which was subjected to the same machining test as in example with a dressing interval of 95.

On the basis of example one, the amount of filler SiC was increased from 3.6g to 9g, and the remainder was kept constant to obtain a grinding wheel, which was subjected to the same machining test as in example with a dressing interval of 80.

On the basis of the first embodiment, the grinding wheel is sintered after cold pressing, the hot pressing step is omitted, and the rest is unchanged, so that the obtained grinding wheel is cracked and cannot be applied.

When the nano ceramic cBN pore grinding wheel is prepared, the nano inorganic material raw materials are creatively mixed, the acrylic microspheres are uniformly dispersed in the inorganic components of the ceramic raw materials in a rotary evaporation mode, and the acrylic microspheres are stabilized in a ceramic biscuit in a hot pressing and curing mode, so that a series of problems of overlarge grinding wheel taper, surface cracks and the like caused by the influence of temperature rise during sintering are solved, and the grinding wheel prepared after sintering has small taper, consistent pore diameter size and uniform distribution; the method for preparing the nano ceramic cBN pore grinding wheel is not approximately reported.