Preparation method of shape-fixable hyperfine stacked abrasive

Abstract

The invention discloses a preparation method of a shape-fixable hyperfine stacked abrasive material, which comprises the following steps: mixing an abrasive material, a sol binder, a low-temperature adhesive, a pore-forming agent and a stabilizer, and adding a proper amount of water to obtain a mixture, the sol binder comprising SiO2, Al2O3, B2O3, Na2O, CaO and BaO, and the low-temperature adhesive comprising SiO2, Al2O3, B2O3, Na2O, CaO and BaO; putting the mixture into rolling equipment, and filling a mold with the mixture; heating, curing and molding the mixture in a mold; stripping the dried mold from the bonding carrier to obtain an abrasive green body; sintering the abrasive green body; and taking out the sintered slightly-bonded stacked abrasive material, crushing and sieving to obtain a finished product of the stacked abrasive material. According to the preparation method of the shape-fixable hyperfine stacked abrasive, selection of a sol binding agent is improved, and the problems of poor abrasive dispersity, non-uniform sol binding agent distribution, uncontrollable hardness and the like are further solved while the grinding precision of the stacked abrasive is improved; the surface consistency of stacked abrasives is improved, the grinding efficiency is improved, and the use requirement is met.

Description

Technical Field

[0001] The present invention relates to the technical field of stacked abrasives, and particularly to a method for preparing superfine stacked abrasives with a definable shape. Background Art

[0002] With the development of modern manufacturing industries, such as aerospace, electronics, optical instruments, etc., the requirements for the machining accuracy of components are getting higher and higher. However, traditional stacked abrasives with ceramic bond are difficult to achieve ultra-precision grinding and cannot meet the needs of these high-end manufacturing industries. High-precision grinding tools are required to ensure the surface quality and dimensional accuracy during grinding. Moreover, traditional stacked abrasives have a single shape, poor surface consistency, and a narrow scope of application.

[0003] Disadvantages of traditional stacked abrasives prepared with ceramic bond: 1. Limited by characteristics such as nanoscale bond and poor dispersion of fine abrasives, they cannot meet the accuracy requirements of high-precision grinding; 2. During the mixing process, it is extremely easy to cause uneven distribution of abrasives and bond, resulting in abrasive-rich areas and bond-rich areas, leading to the inability of the stacked abrasives to always maintain good self-sharpening during the machining process.

[0004] Disadvantages of traditional stacked abrasives prepared with resin bond: 1. The hardness is uncontrollable. When the hardness is high, scratches are likely to appear during grinding; when the hardness is low, the grinding life is affected; 2. During grinding, the temperature is relatively high, which will cause softening and decomposition, affecting the grinding accuracy; 3. The wear resistance of the resin bond is relatively weak. During long-term grinding, the bond itself is easily worn, resulting in premature shedding of abrasives and reducing the service life of the grinding tool; 4. The chemical stability is limited. When in contact with some organic solvents or strong acid-base environments, the stacked abrasives prepared therefrom may be affected, resulting in corrosion, dissolution, etc., thereby affecting the performance and structural integrity of the grinding tool.

[0005] Disadvantages of traditional stacked abrasives prepared with metal bond: 1. The metal bond has a strong ability to hold abrasive particles, the chip space between abrasive grains is small, and the chips generated during grinding are easily accumulated on the surface, causing clogging and affecting the grinding effect and efficiency; 2. Although the thermal conductivity of the metal bond is good, it may still cause poor heat dissipation due to chip clogging and other reasons, resulting in an increase in the temperature of the grinding area, thereby affecting the surface quality of the workpiece; 3. The metal materials used in some metal bonds have high costs, and the preparation process is complex. For example, powder metallurgy requires high-temperature sintering, etc., resulting in an increase in production costs; 4. During the production process of metal bonds, the use of the metal oxide reduction method will result in high impurity content and poor stability; the products obtained by the electrolysis method have poor stability and poor antioxidant ability; the chemical precipitation method has a complex process and extremely poor antioxidant performance and is prone to spontaneous combustion.

[0006] Regardless of the type of binder, the traditional stacked abrasives made from it have a single shape. Although they have certain self-sharpening and sharpness, their surface consistency is poor, the applicable range is generally narrow, and when using stacked abrasives to prepare sandcloth, sand belts, etc., they cannot meet the requirements of high flatness, and their applications have certain limitations. For example: Chinese Patent CN111659317A discloses a preparation method of hollow spherical stacked abrasives; Chinese Patent CN108994746A discloses a preparation method of strip-shaped stacked abrasives formed by extrusion; Chinese Patent CN117720879A discloses a method for preparing stacked abrasives by extrusion using a twin-screw granulator; the stacked abrasives prepared in the above three patents have a single shape. When using this type of stacked abrasives to prepare sandcloth and sand belts, the grinding surface area is inconsistent at different grinding stages, resulting in unstable grinding performance. Moreover, the stacked abrasives formed by extrusion are prone to deformation, and the abrasive distribution is uneven after the irregular stacked abrasives are made into sand belts, the surface consistency is poor, and the grinding efficiency is low. Summary of the Invention

[0007] An object of the present invention is to provide a preparation method of superfine stacked abrasives with a definable shape, improve the sol binder, break through problems such as poor abrasive dispersion, uneven binder distribution, and uncontrollable hardness while greatly improving the grinding accuracy of the stacked abrasives; and replace the conventional granulation method to greatly improve the surface consistency of the stacked abrasives, improve the grinding efficiency, and meet different usage requirements.

[0008] To achieve this purpose, the present invention adopts the following technical solutions:

[0009] A preparation method of superfine stacked abrasives with a definable shape, comprising the following steps:

[0010] Mix abrasives, sol binder, low-temperature adhesive, pore-forming agent and stabilizer, and add an appropriate amount of water to obtain a mixture, wherein the components of the sol binder include SiO2, Al2O3, B2O3, Na2O, CaO, BaO;

[0011] Put the mixture into a roll pressing device and fill it into a mold;

[0012] The mixture is heated and cured in the mold to form a shape;

[0013] Separate the dried mold from the bonding carrier to obtain a green abrasive blank. Among them, the hole shapes of the mold include: prisms (including but not limited to cubes and cuboids), pyramids (including but not limited to triangular pyramids and quadrangular pyramids), frustums of pyramids, cylinders, cones, frustums of cones, spheres, spherical segments, spherical frustums, toroids, barrel-shaped bodies, and three-dimensional geometric bodies composed of any two or more of the above regular geometric bodies. The types of molds include silicone molds, rubber molds, metal molds, plastic molds, screen molds, fiberglass molds, ceramic molds, casting molds, glass product molds, plastic molds, extrusion and stamping molds, and pouring molds. The hole types of the mold include: through holes and blind holes;

[0014] Sinter the green abrasive blank;

[0015] Take out the slightly bonded stacked abrasive after sintering, and obtain the finished product of stacked abrasive after crushing and sieving.

[0016] As a preferred technical solution, the weight percentages of the components in the sol binder are as follows: 50-70wt% SiO2, 5-20wt% Al2O3, 5-20wt% B2O3, 2-10wt% Na2O, 2-10wt% CaO, 1-5wt% BaO.

[0017] As a preferred technical solution, the preparation process of the sol binder is specifically as follows: Mix SiO2, Al2O3, B2O3, Na2O, CaO, and BaO with water and put them into silica sol, place them in an 80°C water bath, add an acidic catalyst to adjust the pH to 3, and induce the formation of a gel state to obtain the sol binder.

[0018] As a preferred technical solution, the silica sol is a dispersion of 10-20nm silica in water, and the nano-alumina in it has a crystal form of γ-Al2O3 and a particle size of 10-20nm.

[0019] As a preferred technical solution, in the preparation process of the sol binder, a pH buffer is used, and sodium tetraborate decahydrate is used as the boron source.

[0020] As a preferred technical solution, during the heating and curing molding process, the drying temperature is 90°C and the time is 60min.

[0021] As a preferred technical solution, during the sintering process of the green abrasive blank, the sintering curve is: 20-380°C, 6°C / min, hold for 20min; 380-580°C, 5°C / min, hold for 20min; 580-700°C, 3 / min, hold for 60min; the sintering pressure is normal pressure.

[0022] As a preferred technical solution, the low-temperature adhesive comprises one or more of natural adhesives (dextrin powder, yellow dextrin, animal glue), semi-synthetic adhesives (sodium alginate, carboxymethyl cellulose), and synthetic adhesives (sodium silicate, polyvinyl alcohol, polystyrene, polyvinyl acetate).

[0023] As a preferred technical solution, the pore-forming agent is one or more of inorganic pore-forming agents (ammonium carbonate, carbon particles, ammonium bicarbonate) and organic pore-forming agents (walnut shell powder, polyvinyl chloride, urea).

[0024] As a preferred technical solution, the stabilizer is one or more of polytetrafluoroethylene, fumed silica, and xanthan gum.

[0025] It should be further noted that, aiming at the problems of low grinding accuracy, poor abrasive dispersibility, uneven distribution of binder, uncontrollable hardness, etc. in traditional stacked abrasive grinding, the sol binder proposed in this application uses nano-scale micropowders in terms of composition to ensure a greatly improved grinding accuracy of stacked abrasives. Due to the excellent dispersibility of the sol binder, the problems of poor dispersibility of ultra-fine abrasives and uneven dispersion of the sol binder are greatly solved, and the properties of the binder can also be controlled by controlling the proportions of different substances in the sol binder.

[0026] The specific control methods are as follows: 1. Control the refractoriness of the sol binder by controlling the contents of Al2O3, SiO2, and B2O3. The presence of SiO2 and Al2O3 in the sol binder will increase the refractoriness of the sol binder, and the influence of Al2O3 on the refractoriness of the sol binder is greater than that of SiO2, but Al2O3 will reduce the fluidity of the sol binder; 2. Control the fluidity of the sol binder by controlling the content of B2O3. The presence of B2O3 will reduce the refractoriness of the sol binder and increase the fluidity of the sol binder; 3. Control the thermal expansion coefficient of the sol binder by controlling the contents of Al2O3, B2O3, and Na2O; 4. Control the flexural strength of the sol binder by controlling the contents of Al2O3, B2O3, and Na2O. A ceramic binder with a higher flexural strength can make the structure of the stacked abrasives more stable; 5. Control the microhardness of the sol binder by controlling the content of SiO2. The higher the content of SiO2, the greater the microhardness of the sol binder, which makes the sol binder have a stronger holding force on the abrasives, and the abrasives are more firmly attached to the sol binder during the grinding process, reducing the premature shedding of the abrasives and improving the service life of the grinding tool.

[0027] Therefore, in the preparation process of the sol binder, according to the weight percentage of the following components: 50-70wt% SiO2, 5-20wt% Al2O3, 5-20wt% B2O3, 2-10wt% Na2O, 2-10wt% CaO, 1-5wt% BaO, the corresponding mass of inorganic salt powder (except sodium tetraborate decahydrate) is weighed and dissolved and mixed; in order to promote the dissolution and uniform mixing of the inorganic salt, the silica sol is first heated and stirred at a constant temperature of 40-60°C and a speed of 300r / min for ten minutes; then the mixed inorganic salt mixed solution is added to the silica sol for mechanical stirring. Mechanical stirring, the parameters remain unchanged, and 0.2 mol / L dilute hydrochloric acid is used to adjust the pH of the sol to 2-3, then sodium tetraborate decahydrate powder is added to the sol and stirred for another 40-60 minutes; during the stirring process, surfactants such as sodium dodecyl sulfate, polyethylene glycol, DMF, etc. are added to reduce the surface tension of the surface of the silica-alumina sol particles, reduce agglomeration, and improve the stability and uniformity of the sol; the temperature is further increased to 60-80°C, the pH is adjusted to 3-5 with diluted ammonia water, and stirred for 60-90 minutes. After the stirring is completed, the sol is transferred and placed in a 30°C environment for aging for 48 hours to form a stable sol binder.

[0028] Aiming at the characteristics of low flatness and poor surface consistency of traditional stacked abrasives, a mold granulation method is adopted to prepare stacked abrasives with regular shapes, which fundamentally solves the problems of low flatness and poor surface consistency. The specific implementation method is as follows: different shapes of molds are selected, the mixed abrasives are filled into the molds for drying and demoulding, and a stacked abrasive green body with regular shape is obtained, and then sintering is performed to ensure that the shape of the stacked abrasive does not change after sintering.

[0029] The beneficial effects of the present invention are: providing a method for preparing ultra-fine stacked abrasive with a definable shape, which has the following advantages:

[0030] 1. Compared with traditional deposited abrasives, a new type of sol binder is used to increase the processing accuracy of deposited abrasives from micron level to nanometer level;

[0031] 2. The use of sol binder solves the problem of poor dispersibility of traditional stacked abrasives in ultra-fine abrasives and uneven dispersion of binders;

[0032] 3. It can be made into stacked abrasives of different regular shapes, which greatly improves the surface consistency of the bonded abrasive tool;

[0033] 4. The stacked abrasive prepared with sol binder has good chemical stability and can maintain good grinding performance in acid, alkali and other chemical environments;

[0034] 5. The stacked abrasive prepared with sol binder has good high temperature resistance and will not soften or lose binding force due to high temperature, thus ensuring the shape and grinding performance of the abrasive tool;

[0035] 6. The hardness of the stacked abrasive prepared with a sol binder is controllable, making it difficult for the abrasives to fall off during the grinding process, thus significantly improving the service life of the grinding tool.

[0036] 7. The self-sharpening and sharpness of the fabricated stacked abrasive are greatly improved compared to traditional stacked abrasives. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The present invention will be further described in detail below with reference to the drawings and embodiments.

[0038] Figure 1 FIG. is a comparison diagram of the sand surfaces after grinding of the stacked abrasive described in the embodiment (the left side is the abrasive of the competitor, and the right side is the abrasive of the present application);

[0039] Figure 2 FIG. is a comparison diagram of the sand surfaces before grinding of the stacked abrasive described in the embodiment (the left side is the abrasive of the competitor, and the right side is the abrasive of the present application);

[0040] Figure 3 FIG. is a physical diagram of the sintered stacked abrasive described in the embodiment. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0041] The technical solution of the present invention will be further described below in conjunction with the drawings and through specific embodiments.

[0042] Embodiment 1:

[0043] The technological process of the stacked abrasive is as follows:

[0044] (1) Mold: Select a quadrangular prism - rubber through-hole mold;

[0045] (2) Mixing: Mix 68.0% by mass of GCP2000 green silicon carbide abrasive, 32.0% of sol binder, 20% of 4wt% PVA solution (low-temperature adhesive), 0.3% of polyvinyl chloride (pore-forming agent), 0.3% of xanthan gum (stabilizer) with an appropriate amount of water to obtain a mixed material (where the low-temperature adhesive, pore-forming agent, and stabilizer are not unique);

[0046] (3) Forming: Mechanically roll-press and fill the mixed material prepared in step (2) into the surface holes of the quadrangular prism - rubber through-hole mold;

[0047] (4) Drying: Heat and cure the mold in step (3) to set the shape, where the drying temperature is 90°C and the time is 60 min;

[0048] (5) Demolding: Peel the dried mold in step (4) from the bonding carrier to obtain a quadrangular pyramid-shaped stacked abrasive green body;

[0049] (6) Sintering: Sinter the stacked abrasive green body in step (5). The sintering curve is as follows: 20 - 380 °C, at a rate of 6 °C / min, with a holding time of 20 min; 380 - 580 °C, at a rate of 5 °C / min, with a holding time of 20 min; 580 - 700 °C, at a rate of 3 °C / min, with a holding time of 60 min; the sintering pressure is normal pressure;

[0050] (7) Sorting: Take out the slightly adhered stacked abrasive, and after crushing and screening through 12 - mesh and 20 - mesh sieves, obtain the finished product of prismatic - stacked abrasive.

[0051] Example Two:

[0052] The technological process of the stacked abrasive is as follows:

[0053] (1) Mold: Select a prismatic - rubber - made blind - hole rubber - made mold;

[0054] (2) Mixing: Mix 88.0% by mass of CP180 silicon carbide abrasive, 12.0% of sol binder, 0.3% of walnut shell powder (pore - forming agent), 0.3% of xanthan gum (stabilizer), 0.3% of yellow dextrin (low - temperature adhesive), and an appropriate amount of water evenly to obtain a mixture;

[0055] (3) Forming: Mechanically roll - press and fill the mixture prepared in step (2) into the surface holes of the prismatic - rubber - made blind - hole rubber - made mold;

[0056] (4) Drying: Heat and cure the mold in step (3) to set its shape. The drying temperature is 90 °C and the time is 60 min;

[0057] (5) Demolding: Peel the dried mold in step (4) from the bonding carrier to obtain a pyramidal - shaped stacked abrasive green body;

[0058] (6) Sintering: Sinter the stacked abrasive green body in step (5). The sintering curve is as follows: 20 - 380 °C, at a rate of 6 °C / min, with a holding time of 20 min; 380 - 580 °C, at a rate of 5 °C / min, with a holding time of 20 min; 580 - 700 °C, at a rate of 3 °C / min, with a holding time of 60 min; the sintering pressure is normal pressure;

[0059] (7) Sorting: Take out the slightly adhered stacked abrasive, and after crushing and screening through 12 - mesh and 20 - mesh sieves, obtain the finished product of prismatic - stacked abrasive.

[0060] In each example, when preparing the sol binder, use the following formula ratio in the table.

[0061] Table 1 Content of each component in the sol binder

[0062] Component <![CDATA[SiO2]]> <![CDATA[Al2O3]]> <![CDATA[B2O3]]> <![CDATA[Na2O]]> CaO BaO Formulation 1 40 20 30 5 5 0 Formulation 2 50 20 20 5 5 0 Formulation 3 50 20 20 5 0 5 Formulation 4 50 10 30 5 5 0 Formulation 5 50 10 20 15 5 0 Formulation 6 50 20 10 15 5 0 Formulation 7 50 20 15 10 5 0 Formulation 8 50 20 15 10 0 5 Formulation 9 60 10 20 5 5 0 Formulation 10 60 20 10 5 5 0 Formulation 11 60 15 15 5 5 0

[0063] Table 2 Influence of the content of each component on the performance of the sol binder

[0064]

[0065]

[0066] Table 3 Influence of the proportion of the sol binder on the hardness of the stacked abrasive

[0067]

[0068] The comparison of the grinding test results is as follows:

[0069]

[0070] It should be noted that the above specific implementation manners are only the preferred embodiments of the present invention and the applied technical principles. Any changes or substitutions that are easily conceivable by those skilled in the art within the technical scope disclosed by the present invention should be covered by the protection scope of the present invention.

Claims

1. A preparation method of a superfine-packed abrasive with a definable shape, characterized in that It includes the following steps: Mix abrasive, sol binder, low-temperature adhesive, pore-forming agent and stabilizer, and add an appropriate amount of water to obtain a mixture. Among them, the components of the sol binder include SiO2, Al2O3, B2O3, Na2O, CaO, BaO; Put the mixture into a roller press and fill it into a mold; The mixture is heated and cured in the mold to form a shape; Peel the dried mold from the bonding carrier to obtain a green abrasive body. Among them, the hole shapes of the mold include: prism, pyramid, frustum of a pyramid, cylinder, cone, frustum of a cone, sphere, spherical segment, spherical frustum, torus, barrel-shaped body, and a three-dimensional geometric body composed of any two or more of the above regular geometric bodies; the types of molds include: silicone mold, rubber mold, metal mold, rubber mold, screen mold, glass fiber mold, ceramic mold, casting mold, glass product mold, plastic mold, extrusion stamping mold, perfusion mold; the hole types of the mold include: through hole, blind hole; Sinter the green abrasive body; Take out the slightly bonded stacked abrasive after sintering, and obtain the finished product of stacked abrasive after crushing and sieving.

2. The preparation method of a shape-determinable ultra-fine packed abrasive according to claim 1, characterized in that The weight percentages of the components in the sol binder are as follows: 50-70wt% SiO2, 5-20wt% Al2O3, 5-20wt% B2O3, 2-10wt% Na2O, 2-10wt% CaO, 1-5wt% BaO.

3. A method for preparing a superfine packed abrasive with a definable shape according to claim 1, characterized in that, The specific preparation process of the sol binder is: mix SiO2, Al2O3, B2O3, Na2O, CaO, BaO with water and put them into silica sol, place them in an 80°C water bath, add an acidic catalyst to adjust the pH to 3, and induce the formation of a gel state to obtain the sol binder.

4. The preparation method of a shape-determinable ultra-fine packed abrasive according to claim 3, characterized in that, The silica sol is a dispersion of 10-20nm silica in water, and the nano-alumina in it has a crystal form of γ-Al2O3 and a particle size of 10-20nm.

5. The method for preparing a shape-determinable ultra-fine packed abrasive according to claim 3, wherein During the preparation process of the sol binder, a pH value buffer is used, and sodium tetraborate decahydrate is used as the boron source.

6. The method for preparing a superfine packed abrasive with a definable shape according to claim 1, characterized in that, During the heating and curing process, the drying temperature is 90°C and the time is 60min.

7. A method for preparing a superfine packed abrasive with a definable shape according to claim 1, characterized in that, During the sintering process of the green abrasive body, the sintering curve is: 20-380°C, 6°C / min, hold for 20min; 380-580°C, 5°C / min, hold for 20min; 580-700°C, 3 / min, hold for 60min; The sintering pressure is normal pressure.

8. A method for preparing a shape-determinable ultra-fine packed abrasive according to claim 1, characterized in that, The low-temperature adhesive includes one or more of natural adhesives, semi-synthetic adhesives and synthetic adhesives.

9. The method for preparing a superfine packing abrasive with a definable shape according to claim 1, wherein The pore-forming agent is one or more of inorganic pore-forming agents and organic pore-forming agents.

10. The preparation method of a shape-determinable ultra-fine packed abrasive according to claim 1, characterized in that, The stabilizer is one or more of polytetrafluoroethylene, fumed silica, xanthan gum.

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