Preparation method of oil stone grinding wheel and oil stone grinding wheel prepared by the method

Abstract

The application provides a preparation method of an oil stone grinding wheel and an oil stone grinding wheel prepared by the method, and relates to the technical field of abrasive tool manufacturing. The method comprises the following steps: S1, oil stone body injection molding, mixing oil stone abrasive, a binder and paraffin into slurry, and then injecting the slurry into a mold to form an oil stone body after dewaxing and sintering; S2, plastic base injection molding, manufacturing an engineering plastic base with a matching inner hole or groove; S3, side surface bonding, bonding and solidifying the oil stone body and the base at the side surface by using high-strength glue; and S4, post-processing, performing size detection, dynamic balance correction and surface finishing. The obtained oil stone grinding wheel is composed of an injection-molded integral oil stone body and an injection-molded plastic base and is bonded at the side surface. The application realizes high-uniform molding of the oil stone, adaptation to complex shapes and improvement of the production environment. The structural design significantly reduces the cost and improves the reliability through side surface connection, and is suitable for precise and efficient grinding.

Description

Technical Field

[0001] This invention relates to the field of abrasive manufacturing technology, specifically to a method for preparing a composite oilstone grinding wheel using injection molding, and the oilstone grinding wheel product obtained by this method. Background Technology

[0002] There are two prominent problems in the current preparation of oilstone grinding wheels: First, the forming process mostly adopts dry powder pressing, in which a mixture of abrasive and binder dry powder is loaded into a mold and pressed under high pressure to obtain a blank. This process has the drawbacks of poor density uniformity, i.e., uneven pressure transmission leads to density differences between the center and the edge of the blank, limited shape, i.e., only suitable for simple axisymmetric shapes, and serious dust pollution, i.e., the dust flying during dry powder operation affects the environment and workers' health. Second, traditional oilstone grinding wheels mostly adopt a two-section structure, i.e., the oilstone part for grinding and the non-grinding clamping part are formed by end face bonding or integral sintering. This has the problems of high material cost and complex process for the non-grinding part of the grinding wheel, as well as insufficient reliability due to the small end face bonding area, which makes it easy to stress concentration fracture or loosening under high speed and high load. Summary of the Invention

[0003] This invention aims to address the shortcomings of traditional dry powder pressing molding and two-section structures, and provides a method for preparing an oilstone grinding wheel and the oilstone grinding wheel obtained therefrom. The oilstone body and plastic base are prepared by injection molding process and side bonding assembly is adopted to achieve high-density uniform molding, complex shape adaptation, low dust and environmental protection, low cost and high reliability.

[0004] This invention provides the following technical solution: A method for preparing an oilstone grinding wheel includes the following steps: S1: Injection molding of oilstone body: Mix oilstone abrasive, binder and paraffin wax to form a slurry, and then perform injection molding, dewaxing and sintering to obtain the oilstone body; S2: Plastic base injection molding: The clamping base with an inner hole or inner groove is manufactured by injection molding process using engineering plastics. S3: Side bonding assembly: Insert the oilstone body into the inner hole or groove of the plastic base, and bond and cure them on the side contact surfaces of the two with adhesive. S4: Post-processing: Perform dimensional inspection, dynamic balancing correction, and surface finishing on the bonded oilstone grinding wheel.

[0005] Preferably, step S1 specifically includes: Slurry preparation: At a temperature of 100-150℃, the oilstone abrasive, binder and paraffin wax accounting for 10%-13% of the total mass of the abrasive and binder and having a melting point of 50-60℃ are thoroughly and evenly mixed as wetting agent and temporary binder to form a high-flowability high-temperature slurry. Pneumatic injection: High-temperature slurry is fed into a pneumatic injection machine and injected into a mold cavity that has been pre-cooled to 20-30°C using air pressure or plunger pressure. The slurry solidifies instantly in the cold mold to obtain a high-precision oilstone green body. Dewaxing process: The oilstone body green body is sent into a dewaxing furnace to remove the paraffin wetting agent by heating or solvent immersion; High-temperature sintering: The dewaxed oilstone body green body is sintered at high temperature to solidify the abrasive and binder, resulting in a high-strength and high-density oilstone body.

[0006] The technical advantage lies in the fact that by employing an injection molding process that includes slurry mixing, pneumatic injection, dewaxing, and sintering to prepare the oilstone body, and combining this with an injection-molded plastic base and side bonding, this method can produce oilstone wheels with novel structures. Utilizing the excellent fluidity of the high-temperature slurry and the rapid shaping of the cold mold, the density uniformity of the molded preform is effectively improved, making it suitable for manufacturing oilstone bodies with complex cross-sectional shapes. Simultaneously, the slurry operation replaces the traditional dry powder operation, reducing dust generation during production. The engineering plastic base and side bonding structure achieves reliable component connection while simplifying the product structure and enabling lower manufacturing costs and a more versatile base design.

[0007] Preferably, in the slurry mixing process, the oilstone abrasive is CBN or diamond, and the binder is a ceramic, metal, or resin-based binder.

[0008] The technical advantage lies in the specific limitation of the oilstone abrasive to CBN or diamond, and the binder to ceramic, metal, or resin-based materials, clarifying that the method of this invention is particularly suitable for the preparation of superhard abrasive oilstone wheels. This limitation indicates that the injection molding process can be adapted to different binder systems, providing a feasible process path for preparing oilstone products that meet the requirements of various grinding conditions.

[0009] Preferably, in the pneumatic injection, the injection pressure is 0.5-1.5 MPa.

[0010] Preferably, in the dewaxing process, the heating dewaxing is carried out under inert gas protection, with a heating rate of 2-5℃ / min, a temperature of 280-320℃, and a holding time of 1.5-2.5 hours. The solvent immersion dewaxing is carried out by immersion in xylene or acetone for 2-4 hours.

[0011] Preferably, in the high-temperature sintering, the ceramic binder is sintered at 1300-1400℃, the metal binder at 1150-1250℃, and the resin binder at 800-900℃, and the temperature is maintained for 2-3 hours.

[0012] Preferably, the plastic base is injection molded from polyamide 66, polyphenylene sulfide, or ABS engineering plastic, and the base can be used with different lengths of oilstone bodies but with the same clamping position size.

[0013] The technical advantage lies in specifying the material of the plastic base as engineering plastics such as polyamide 66, polyphenylene sulfide, or acrylonitrile-butadiene-styrene copolymer, and clarifying that it can be manufactured using injection molding. This combination of materials and processes is key to achieving low-cost manufacturing of the clamping components. Furthermore, the base's universal design, adaptable to different lengths of whetstone bodies, reduces the need for molds for different product specifications, thus lowering production costs and increasing production flexibility.

[0014] Preferably, in the side bonding, the adhesive is epoxy resin, polyurethane, or modified acrylate adhesive, with a coating thickness of 0.05-0.2 mm, and is cured at room temperature for 12-24 hours or heated at 50-80°C for 2-4 hours.

[0015] Preferably, in the post-processing, the dimensional inspection includes radial runout ≤0.05mm, flatness ≤0.03mm, and dynamic balance ≤5g·cm.

[0016] An oilstone grinding wheel prepared by the above method comprises: The main body of the oilstone is an integral grinding component manufactured by injection molding; The plastic base is an injection-molded engineering plastic clamping component, which has an inner hole or groove for the oilstone body to be inserted. The side of the oilstone body is fixedly connected to the inner wall of the plastic base by adhesive.

[0017] This oilstone grinding wheel is constructed by side bonding of a monolithic oilstone body, manufactured through injection molding, and an injection-molded engineering plastic base. This structure combines the advantages of the injection-molded oilstone body—uniform density and the ability to form complex shapes—with the lightweight, low-cost, and easy-to-mold characteristics of the engineering plastic base. Compared to traditional end-face bonding, side bonding typically provides a larger effective bonding area, thus helping to improve the mechanical properties and overall reliability of the connection. This product structure offers a concrete solution for achieving low-cost, high-reliability oilstone grinding wheels.

[0018] The beneficial effects of this invention are: The main body of the oilstone of this invention adopts injection molding process, which has good slurry fluidity, uniform molding pressure distribution, and the uniformity of green body density is significantly better than that of traditional dry powder pressing. It is suitable for complex or irregular cavities. Slurry operation replaces dry powder operation, which greatly reduces the dust concentration in the production environment. The plastic base material and injection molding process have lower costs, and the base can be used with oilstones of different lengths, reducing mold investment. The side bonding area is significantly increased compared with the end face bonding, resulting in high connection strength and no risk of breakage or loosening during high-speed use. Attached Figure Description

[0019] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings: Figure 1 This is a cross-sectional schematic diagram of the structure of the oilstone grinding wheel of the present invention; Figure 2 This is a schematic diagram of a traditional oilstone grinding wheel. Markings in the diagram: 1. Oilstone abrasive; 2. Grinding wheel material clamping; 3. Adhesive layer; 4. Engineering plastic base. Detailed Implementation

[0020] Example 1: Preparation of a CBN ceramic bonded oilstone grinding wheel This embodiment details the complete manufacturing process of a CBN ceramic oilstone grinding wheel.

[0021] S1. Injection molding of the main body using an oilstone (1) Slurry mixing: Cubic boron nitride (CBN) abrasive with a particle size of 80# and a ceramic binder were selected, and paraffin wax with a melting point of 52℃ and accounting for 12% of the total mass of the abrasive and binder was added as a temporary binder and wetting agent. The above raw materials were placed in a mixer and thoroughly mixed for 30 minutes at a temperature of 120℃ and a vacuum of -0.08MPa to form a uniform, highly fluid high-temperature slurry.

[0022] (2) Pneumatic injection: The mixed high-temperature slurry is fed into a pneumatic injection molding machine. Using a constant air pressure of 0.8 MPa, the slurry is injected into a mold cavity pre-cooled to 25°C, the shape of which matches the desired shape of the asphalt stone body, such as rectangular or trapezoidal. The high-temperature slurry solidifies rapidly in the cold mold, resulting in a green asphalt stone body with high dimensional accuracy.

[0023] (3) Dewaxing treatment: The oilstone body is fed into a dewaxing furnace and slowly heated to 300°C at a heating rate of 3°C / min under a nitrogen protective atmosphere. It is then held at this temperature for 2 hours to allow the paraffin wax to completely melt and be discharged.

[0024] (4) High-temperature sintering: The dewaxed green body was transferred to a sintering furnace and sintered in air at a heating rate of 5°C / min to 1350°C, and held at that temperature for 3 hours. After sintering, it was allowed to cool naturally to room temperature, resulting in a dense and high-strength CBN ceramic binder asphalt matrix.

[0025] S2. Injection molding of plastic base Using polyamide 66 (PA66) engineering plastic granules, a clamping base with a rectangular inner hole is manufactured through conventional injection molding. The width of the inner hole of this base is designed to be 0.1 mm larger than the corresponding width of the oilstone body (i.e., a single-sided fitting clearance of 0.05 mm). This base is a universal design and can be adapted to oilstone bodies of different lengths with the same clamping width.

[0026] S3. Side bonding assembly Using a dispensing device, a two-component epoxy resin adhesive is evenly applied to the side surface of the whetstone body to be joined, prepared in step S1, with the adhesive layer thickness controlled at 0.1 mm. Immediately afterwards, the adhesive-coated whetstone body is inserted axially into the rectangular inner hole of the plastic base, and slight pressure is applied to ensure adhesion. The mixture is allowed to cure at room temperature (25°C) for 24 hours to allow the adhesive layer to fully cure, achieving a firm connection between the whetstone body and the plastic base.

[0027] S4. Post-processing The following treatments are applied to the bonded and assembled oilstone grinding wheel: Dimensional inspection: Use a radial runout checker and a flatness gauge to measure and ensure that the radial runout is ≤0.04mm and the flatness is ≤0.02mm.

[0028] Dynamic balancing correction: The dynamic balance is checked and corrected on a dynamic balancing machine to ensure that the residual dynamic balance is ≤4.5g·cm.

[0029] Surface finishing: Use fine sandpaper or a small grinder to remove burrs and adhesive residue from the workpiece surface, making the grinding surface flat and smooth.

[0030] Example 2: Preparation of a diamond-bonded oilstone grinding wheel The difference between this embodiment and Embodiment 1 lies in the selection of materials and some process parameters, in order to demonstrate the adaptability of the present invention.

[0031] S1. Injection molding of the main body using an oilstone (1) Slurry preparation: Diamond abrasive with a particle size of 100# and copper-tin alloy (Cu-Sn) metal binder were used. The temporary binder was still paraffin wax, added at 11% of the total mass, with a melting point of 55°C. The mixing conditions were the same as in Example 1.

[0032] (2) Pneumatic injection: The process is the same as in Example 1, but the injection pressure is 1.0 MPa.

[0033] (3) Dewaxing treatment: Solvent immersion dewaxing is used. The green blank is completely immersed in a container containing acetone and soaked at room temperature for 3.5 hours. After removal, it is placed in an oven at 80°C for 1.5 hours to completely remove residual solvent and paraffin.

[0034] (4) High-temperature sintering: Under a hydrogen protective atmosphere, the green blank is heated to 1180°C at 8°C / min and held for 2 hours to obtain the diamond metal bonded oilstone body.

[0035] S2. Injection molding of plastic base The clamping base with an inner hole is manufactured by injection molding using polyphenylene sulfide (PPS) engineering plastic. The clearance between the inner hole and the whetstone body is designed to be 0.12mm.

[0036] S3. Side bonding assembly Modified acrylic structural adhesive (such as two-component reactive acrylic adhesive) is used as the bonding agent. After aligning the whetstone body with the plastic base, the adhesive is applied and the parts are assembled. Then, the parts are placed in an oven at 70°C for 3 hours to cure.

[0037] S4. Post-processing The post-processing steps are the same as in Example 1, and the final product performance meets the following requirements: radial runout ≤ 0.05 mm, flatness ≤ 0.03 mm, and dynamic balance ≤ 5 g·cm.

[0038] Example 3: Preparation of a resin-bonded oilstone grinding wheel and a universal base This embodiment focuses on illustrating the versatility of the resin binder system and the base.

[0039] S1. Injection molding of the main body using an oilstone (1) Slurry preparation: CBN abrasive with a particle size of 150# and phenolic resin binder are used. The amount of paraffin added is 10%, with a melting point of 58℃.

[0040] (2) Pneumatic injection: The process is the same as in Example 1.

[0041] (3) Dewaxing treatment: The same heating dewaxing process as in Example 1 was used, but the final temperature was 280°C and the temperature was maintained for 2 hours.

[0042] (4) High-temperature sintering: Under nitrogen protection, the temperature is increased to 850℃ at 3℃ / min and held for 2.5 hours to carry out curing and sintering, so as to obtain the resin binder CBN oilstone body.

[0043] S2. Injection molding of plastic base A universal base with replaceable clamping blocks is injection molded using acrylonitrile-butadiene-styrene copolymer (ABS) engineering plastic. The base body is designed with a standard interface to accommodate ABS plastic clamping blocks of different inner diameters. In this embodiment, the gap between the inner diameter of the clamping block and the whetstone body is 0.08 mm.

[0044] S3. Side bonding assembly High-performance polyurethane adhesive is used. After application, the adhesive is cured at 50°C for 4 hours.

[0045] S4. Post-processing Same as Example 1.

[0046] Experimental Example: Verification of the Effect of the Oilstone Grinding Wheel of the Invention To verify the technical effect of the oilstone grinding wheel prepared by this invention, the following comparative experiments were conducted.

[0047] Cost comparison analysis: The unit cost of the traditional two-section grinding wheel (end face bonding) and the side-bonded oilstone grinding wheel prepared in Example 1 of this invention was calculated, and the results are shown in Table 1.

[0048] Table 1: Cost Comparison Analysis (Unit: RMB / piece)

[0049] Cost comparison results show that the total cost per component of the traditional structure is approximately 13 yuan, while the total cost per component of the structure of this invention is approximately 8.6 yuan, representing a cost reduction of approximately 34.8%. Specifically, the material cost of the clamping part is reduced from 3.0 yuan for grinding wheel material to 0.8 yuan for engineering plastics; the processing cost is reduced from 3.0 yuan for sintering / machining to 1.0 yuan for injection molding.

[0050] Mechanical performance and reliability testing: Three-point bending strength tests were conducted on the two types of grinding wheels, and the results are shown in Table 2.

[0051] Table 2: Bending Strength Test Results

[0052] Bending strength tests show that the average bending strength of the traditional end-face bonding structure is about 25 MPa, and the failure mode is fracture of the bonding surface. The average bending strength of the side-bonded structure of the present invention is increased to about 43 MPa, and the failure mode is changed to internal fracture of the whetstone or plastic base material. The average bending strength is increased by more than 70%, which proves its high reliability under high speed and high load conditions.

[0053] Therefore, regarding the comparison of structures, refer to Figure 1 and 2This demonstrates the differences between conventional oilstone grinding wheels and the oilstone grinding wheel of this invention: Traditional structure: Part 1 of the oilstone abrasive is clamped to the grinding wheel material and part 2 is connected by an end face bonding layer 3. The non-grinding part is costly. The structure of this invention is as follows: the oilstone abrasive 1 is directly connected to the engineering plastic base 4 through the side adhesive layer 3, and the non-grinding part is made of low-cost plastic, which makes the structure simpler and the mechanical properties better.

[0054] As can be seen from the above embodiments, the present invention achieves high-density uniform forming, low-cost manufacturing, and high-reliability connection of oilstone grinding wheels, solving many defects of traditional processes.

[0055] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing an oilstone grinding wheel, characterized in that, Includes the following steps: S1: Injection molding of oilstone body: Mix oilstone abrasive, binder and paraffin wax to form a slurry, and then perform injection molding, dewaxing and sintering to obtain the oilstone body; S2: Plastic base injection molding: The clamping base with an inner hole or inner groove is manufactured by injection molding process using engineering plastics. S3: Side bonding assembly: Insert the oilstone body into the inner hole or groove of the plastic base, and bond and cure them on the side contact surfaces of the two with adhesive. S4: Post-processing: Perform dimensional inspection, dynamic balancing correction, and surface finishing on the bonded oilstone grinding wheel.

2. The method for preparing an oilstone grinding wheel according to claim 1, characterized in that, The S1 step specifically includes: Slurry preparation: At a temperature of 100-150℃, the oilstone abrasive, binder and paraffin wax accounting for 10%-13% of the total mass of the abrasive and binder and having a melting point of 50-60℃ are thoroughly and evenly mixed as wetting agent and temporary binder to form a high-flowability high-temperature slurry. Pneumatic injection: High-temperature slurry is fed into a pneumatic injection machine and injected into a mold cavity that has been pre-cooled to 20-30°C using air pressure or plunger pressure. The slurry solidifies instantly in the cold mold to obtain a high-precision oilstone green body. Dewaxing process: The oilstone body green body is sent into a dewaxing furnace to remove the paraffin wetting agent by heating or solvent immersion; High-temperature sintering: The dewaxed oilstone body green body is sintered at high temperature to solidify the abrasive and binder, resulting in a high-strength and high-density oilstone body.

3. The method for preparing an oilstone grinding wheel according to claim 2, characterized in that, In the slurry mixing process, the oilstone abrasive is CBN or diamond, and the binder is a ceramic, metal, or resin-based binder.

4. The method for preparing an oilstone grinding wheel according to claim 2, characterized in that, In the pneumatic injection, the injection pressure is 0.5-1.5 MPa.

5. The method for preparing an oilstone grinding wheel according to claim 2, characterized in that, In the dewaxing process, heating dewaxing is carried out under inert gas protection, with a heating rate of 2-5℃ / min, a temperature of 280-320℃, and a holding time of 1.5-2.5 hours. Solvent immersion dewaxing uses xylene or acetone for immersion for 2-4 hours.

6. The method for preparing an oilstone grinding wheel according to claim 2, characterized in that, In the high-temperature sintering process, the ceramic binder is sintered at 1300-1400℃, the metal binder at 1150-1250℃, and the resin binder at 800-900℃, and the temperature is maintained for 2-3 hours.

7. The method for preparing an oilstone grinding wheel according to claim 1, characterized in that, The plastic base is injection molded from polyamide 66, polyphenylene sulfide, or acrylonitrile-butadiene-styrene copolymer engineering plastic, and the base can be used with different lengths of oilstone bodies but with the same clamping position size.

8. The method for preparing an oilstone grinding wheel according to claim 1, characterized in that, In the side bonding process, the adhesive is epoxy resin, polyurethane, or modified acrylic resin, with a coating thickness of 0.05-0.2 mm, and is cured at room temperature for 12-24 hours or heated at 50-80℃ for 2-4 hours.

9. The method for preparing an oilstone grinding wheel according to claim 1, characterized in that, In the post-processing, dimensional inspection includes radial runout ≤0.05mm, flatness ≤0.03mm, and dynamic balance ≤5g·cm.

10. An oilstone grinding wheel prepared by the method according to any one of claims 1-9, characterized in that, include: The main body of the oilstone is an integral grinding component manufactured by injection molding; The plastic base is an injection-molded engineering plastic clamping component, which has an inner hole or groove for the oilstone body to be inserted. The side of the oilstone body is fixedly connected to the inner wall of the plastic base by adhesive.

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