Composite elastic polishing tool for curved surface polishing and preparation method thereof

Abstract

The invention relates to a composite elastic polishing tool which aims at solving the problems that an existing polishing tool is uncontrollable in elasticity, insufficient in hardness and rigidity, poor in abrasive adhesive force, complex in machining, high in cost and the like. The composite elastic polishing tool comprises a conductive elastic base body and an insulating elastic layer, the conductive elastic base body is filled with first reinforcing fibers, the surface of the conductive elastic base body is coated with at least one layer of second reinforcing fibers, and the insulating elastic layer is arranged on the second reinforcing fiber layer. A plurality of regularly distributed micro pits are formed in the insulating elastic layer through laser engraving, and superhard abrasive particles are deposited on the micro pits through electroplating treatment. By adopting the conductive elastic matrix, the reinforced fibers and the insulating elastic layer and combining the laser engraving and electroplating process, the tool is controllable in overall elasticity, outstanding in local rigidity and hardness, firm in abrasive bonding, excellent in tool performance and simple in manufacturing process. The invention further provides a preparation method of the composite elastic polishing tool.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of mechanical polishing, in particular to a composite elastic polishing tool for curved surface polishing and a preparation method thereof. BACKGROUND

[0002] Mechanical polishing is a processing method for removing micro local protrusions on the surface of a workpiece by cutting and plastic deformation of the material surface, so as to obtain a precise and high-quality surface. The method is widely used in the manufacturing fields of precise mechanical parts, aerospace parts and the like, and is an important link in the processing of precise parts, and plays an important role in improving the use performance, service life and appearance quality of products.

[0003] At present, mechanical polishing mainly relies on the following traditional tools: oil stone strip, sandpaper, hundred-grit cloth wheel, wool wheel, rubber wheel, resin wheel and the like. However, the above tools all have obvious defects: the oil stone strip, sandpaper and the like are difficult to adapt to the automatic polishing requirements of curved surface parts; the hundred-grit cloth wheel, wool wheel and the like can realize the automatic polishing of curved surface parts, but their overall service life is short, the dimensional stability is poor, and it is difficult to meet the high-precision polishing requirements; in the rubber or resin polishing wheel, the abrasive is tightly combined with the matrix, and under the action of polishing force, the abrasive is easy to sink into the inside of the wheel body, resulting in very limited polishing effect; the sand belt type polishing tool is usually made of a plane sand belt, and it is difficult to form a large curvature structure required for curved surface polishing.

[0004] Therefore, there is still a lack of a polishing tool in the prior art which can simultaneously meet the requirements of automatic polishing of curved surface parts, long service life, good dimensional stability and high-precision processing. SUMMARY

[0005] In view of the above deficiencies of the prior art, the present application provides a composite elastic polishing tool, aiming to solve the problems of uncontrollable elasticity, insufficient hardness and rigidity, poor abrasive adhesion, complex processing and high cost of the existing polishing tools. By using the conductive elastic matrix, the reinforcing fibers and the insulating elastic layer, combined with the laser engraving and electroplating process, the overall elasticity of the tool is controllable, the local rigidity and hardness are outstanding, the abrasive is firmly combined, the tool performance is excellent and the manufacturing process is simple. The present application also provides a preparation method of the composite elastic polishing tool.

[0006] In order to achieve the above-mentioned purpose, the first aspect of the present application provides a composite elastic polishing tool for curved surface polishing, which comprises a conductive elastic matrix and an insulating elastic layer, the conductive elastic matrix is filled with first reinforcing fibers, and the surface of the conductive elastic matrix is coated with at least one layer of second reinforcing fibers, and the insulating elastic layer is arranged on the second reinforcing fiber layer.

[0007] The insulating elastic layer is laser-engraved to form a plurality of regularly distributed micro-pits, the micro-pit depth is greater than the thickness of the insulating elastic layer, so that the micro-pit bottom exposes the conductive elastic matrix and the first reinforcing fibers filled therein, and the micro-pit sidewall exposes the second reinforcing fibers.

[0008] The micro-pits are deposited with super-hard abrasive particles through electroplating treatment, and the super-hard abrasive particles, the conductive elastic matrix, the first reinforcing fibers and the second reinforcing fibers combine to form hard points.

[0009] Further, the conductive elastic matrix is conductive rubber or conductive elastic polymer. The conductive rubber or conductive elastic polymer is an elastic composite material with a conductive function formed by taking rubber or elastic polymer as a matrix and adding conductive fillers. Its conductive mechanism is that conductive filler particles form a "percolation channel" in the three-dimensional network of the rubber or polymer matrix; when the volume fraction of the conductive filler exceeds the percolation threshold (about 15-20%), the resistivity sharply decreases, realizing continuous conduction.

[0010] In the technical scheme of the present application, the matrix of the conductive rubber is silicone rubber, fluororubber, ethylene-propylene-diene rubber or nitrile rubber; the matrix of the conductive elastic polymer is thermoplastic polyurethane or high molecular weight polydimethylsiloxane (PDMS, Mn≥60k). The conductive filler is graphite, carbon nanotube, single metal particle (including Ag, Cu, Ni, Al) or metal composite particle. The metal composite particle is, for example, nickel-plated copper powder, nickel-plated aluminum powder, silver-plated copper powder, silver-plated aluminum powder, silver-plated glass powder, nickel-coated graphite, etc., and the nickel-plated copper powder is preferred in consideration of performance and cost. The size of the conductive filler is 1-10 μm, and the mass ratio to the matrix is 15-40%, preferably 20-30%. The elastic modulus of the conductive elastic matrix is 0.1-16 MPa, preferably 1-10 MPa; the Shore hardness is 20-60 HA, and the volume resistivity (ρ V ) is 10 -3 ~10 3 Ω·cm, preferably 10 -2 ~10 1 Ω·cm.

[0011] The conductive elastic matrix with the hardness and elastic modulus is suitable as a basic structure of an elastic polishing tool for polishing curved surfaces, especially for polishing curved surfaces that fit large curvature surfaces or complex multi-curvature surfaces. When the elastic modulus or hardness of the conductive elastic matrix is not within the above range, the polishing tool is too soft or too hard and lacks resilience, making it difficult to closely fit the curved surface and provide appropriate pressure to the fitted surface, and cannot meet the technical requirements of automatic polishing of curved surface parts. Moreover, the volume resistivity is suitable for subsequent deposition of superhard abrasive particles by electroplating treatment of the polishing tool.

[0012] Further, the first reinforcing fiber is at least one of metal fiber, carbon fiber, polyester fiber, aramid fiber, and glass fiber, preferably 2 fibers are used in combination, and the filling ratio is 0.5-30 wt% of the mass of the conductive elastic matrix, preferably 3-22 wt%.

[0013] The length of the first reinforcing fiber is 0.5-10 mm, the diameter is 10-50 pm, and the aspect ratio (L / d) is 50-200; preferably the length of the first reinforcing fiber is 1-6 mm, the diameter is 12-40 pm, and the aspect ratio (L / d) is 80-150. The metal fiber can be selected from stainless steel fiber (such as 304, 316L, 630 stainless steel), copper fiber and copper alloy fiber (such as Cu, Cu-Zn, Cu-Sn), aluminum fiber and aluminum alloy fiber (such as Al1050, Al5056). The polyester fiber can be selected from PET fiber or modified PET fiber (such as treated with silane / isocyanate). The aramid fiber can be selected from, for example, poly-p-phenyleneterephthalamide fiber, poly-m-phenyleneterephthalamide fiber, etc. The glass fiber is preferably surface modified by a silane coupling agent to enhance the interfacial shear strength with the elastic matrix.

[0014] By filling the above-mentioned at least one, preferably two, first reinforcing fibers in the elastic matrix, the elastic modulus of the conductive elastic matrix can be adjusted according to the polishing processing requirements, especially to improve the local strength of the elastic matrix when it is deformed to fit a curved surface, so as to provide effective local support for the elastic matrix when polishing a curved surface with a large curvature surface or a complex multi-curvature surface, making the overall elasticity of the polishing tool controllable and the local rigidity and hardness prominent.

[0015] Further, the second reinforcing fiber is polyimide (PI) fiber, polyarylate (PAR) fiber, or meta-aramid fiber. As PI fiber, Evonik P84 ® HT, Dupont™ Kapton ® Type F; as PAR fiber, Kuraray Vectran ® HT, Vectran ®M, X-FIPER ® LCP-F; as meta-aramid fiber, Nomex can be selected ® T-430, Teijin Conex ® T-200.

[0016] The diameter of the second reinforcing fiber is 8-15 μm, preferably 9-12 μm. The pitch between adjacent second reinforcing fibers in the same coating layer can be 2-75 μm, and the adjacent coating layers can be arranged in a ±45° symmetrical manner (i.e., adjacent two layers are orthogonal), taking into account the shear and surface elasticity.

[0017] Preferably, the surface of the conductive elastic matrix is coated with 2-6 layers of second reinforcing fibers.

[0018] Preferably, the second reinforcing fiber is dried at 150°C for 30 min before coating to remove adsorbed moisture.

[0019] Preferably, the tension of the second reinforcing fiber during coating is not more than 10% of the fiber breaking strength, in order to achieve a better balance between elasticity and rigidity. Preferably, the tension of the second reinforcing fiber during coating is 8-10% of the fiber breaking strength.

[0020] Further, the elastic insulation layer is a flexible polyurethane or silicone rubber coating, and the thickness of the elastic insulation layer is 10-150 μm higher than the second reinforcing fiber layer, preferably 20-50 μm higher.

[0021] The elastic insulation layer is applied to the second reinforcing fiber layer by coating (e.g., spraying, brushing or dipping). Since there are gaps between the second reinforcing fibers, at least part of the elastic insulation layer material will enter the gaps of the second reinforcing fiber layer and directly contact the surface of the conductive elastic matrix during coating. By coating the elastic insulation layer on the second reinforcing fiber layer, the second reinforcing fiber layer is sealed and tightly combined with the conductive elastic matrix, which further fixes the fiber layer and improves the medium resistance of the polishing tool. The elastic insulation layer is applied to the second reinforcing fiber layer by coating, which can be cured by heating to form a dense layer, for example, cured at 60-120°C for 1-4 h to form a dense layer.

[0022] Further, the size of the micro-pits is 10-200 μm, the depth is 20-300 μm into the conductive elastic matrix, and the pitch is 5-100 μm. Preferably, the size of the micro-pits is 20-100 μm, the depth is 30-150 μm into the conductive elastic matrix, and the pitch is 10-50 μm.

[0023] The shape of the micro-pits can be set according to specific requirements, such as triangle (including equilateral triangle), rectangle (including square), (regular) pentagon, (regular) hexagon, circle, ellipse, etc. Thus, the size of the micro-pit refers to the maximum width covered by the micro-pit when translated. For example, for a triangular micro-pit, the size refers to the length of the longest side of the triangle; for a rectangular micro-pit, the size refers to the length of the diagonal of the rectangle; for a circular micro-pit, the size refers to the diameter length of the circle. The pitch of the micro-pit refers to the minimum distance between adjacent micro-pits; the regular distribution refers to the same shape, size, pitch and depth of each micro-pit on the polishing tool to form a micro-pit array.

[0024] The laser engraving can be performed according to the prior art and the general experience of those skilled in the art. For example, the laser used can be a 20W pulsed fiber laser (wavelength λ: 1064 nm, pulse width 100 ns, frequency 20 kHz, scanning speed 1000 mm / s, energy density 8 J / cm 2 ; can be scanned multiple times to accumulate to the engraving depth, and is coaxially purged with N2 to reduce spatter and oxidation) or other existing lasers for etching of elastic matrix, and appropriate process parameters are selected according to specific requirements, which can be selected and adjusted as needed by those skilled in the art. Through the above laser engraving, a micro-pit array can be obtained on the elastic insulating layer: for example, a controllable depth micro-pit array of 0.05-0.55 mm, clean exposure of the conductive elastic matrix at the bottom and the reinforcing fibers on the bottom and / or sidewall, no carbonization and no edge lifting at the edge, providing a firm conductive "anchor point" for subsequent electroplating of superhard abrasive.

[0025] Further, the superhard abrasive particles are diamond, cubic boron nitride (CBN), corundum (Al2O3) or SiC, with a particle size of 0.5-30 μm; the nickel (Ni)-superhard abrasive particle composite plating layer is formed in the micro-pit by electroplating to deposit the superhard abrasive particles in the micro-pit. The electroplating can be performed by preparing a Ni-based electroplating solution containing superhard abrasive particles and through a composite electroplating (co-deposition of nickel-abrasive particles) process.

[0026] Further, in the Ni-superhard abrasive particle composite plating layer, the volume fraction of the superhard abrasive particles is 5-50%, preferably 15-45%. Through mechanical embedding and metallurgical bonding of the reinforcing fiber-Ni plating layer-superhard abrasive particle three, the use stability and life of the superhard abrasive particles are increased, and the anti-peeling property of the superhard abrasive particles is greatly improved.

[0027] Further, the composite elastic polishing tool can be in the shape of a plane, or in the shape of a wheel with a wheel core or other specific shape suitable for curved surface polishing.

[0028] In one embodiment, the composite elastic polishing tool is further provided with a support portion inside the conductive elastic matrix, which is used to combine with a driving component (such as a driving system of an automated polishing process, for example, a wheel core) to firmly attach the conductive elastic matrix and the parts thereon on the driving component and transfer the kinetic energy of the driving component to drive the polishing tool to work.

[0029] The second aspect of the present application proposes a preparation method of the composite elastic polishing tool for curved surface polishing as described above, which comprises the following steps:

[0030] (1) Preparing a conductive elastic matrix: mixing an elastic matrix raw material containing a conductive filler with first reinforcing fibers, and then curing and forming to obtain a conductive elastic matrix;

[0031] (2) Coating second reinforcing fibers: coating at least one layer of second reinforcing fibers on the surface of the cured and formed conductive elastic matrix;

[0032] (3) Coating an insulating elastic layer: coating an insulating elastic layer on the second reinforcing fiber layer, and then heating and curing to form a dense layer;

[0033] (4) Laser engraving to form micro-pits: patterning on the surface of the insulating elastic layer by laser engraving to form a plurality of regularly distributed micro-pits, the depth of the micro-pits being greater than the thickness of the insulating elastic layer, so that the bottom of the micro-pits exposes the conductive elastic matrix and the first reinforcing fibers filled therein, and the sidewall of the micro-pits exposes the second reinforcing fibers;

[0034] (5) Electroplating to deposit abrasive particles: depositing super-hard abrasive particles in the micro-pits by electroplating, the super-hard abrasive particles combining with the conductive elastic matrix, the first reinforcing fibers and the second reinforcing fibers to form hard points.

[0035] Further, in step (1), the conductive elastic matrix can be formed into a planar type (such as a thickness of 1-5 mm), a strip type (such as a width of 2-20 mm and a thickness of 1-3 mm), or a wheel type (such as a diameter of 10-200 mm and a thickness of 1-10 mm). It can also be formed into other shapes or composite shapes as needed.

[0036] The curing and forming can be performed by vulcanization or cross-linking of the elastic matrix raw material, and appropriate additives such as anti-aging agents, anti-fatigue agents and / or heat stabilizers, etc. can be added during the curing and forming process to meet the performance requirements of the elastic matrix in the application environment. The mixing can be performed by, for example, planetary stirring and vacuum degassing processes, etc.

[0037] Further, in step (2), the second reinforcing fibers can be applied to the surface of the conductive elastic matrix in individual layers or fiber units, or can be formed into multiple layers in a predetermined arrangement and applied to the surface of the conductive elastic matrix at one time. When applied to the surface of the conductive elastic matrix, a certain tension, for example 2-4 N / cm, is preferably applied to achieve good adhesion of the second reinforcing fibers to the elastic matrix and further adjust the surface hardness of the elastic matrix.

[0038] In one embodiment, after the at least one layer of second reinforcing fibers is coated onto the surface of the conductive elastic matrix, secondary vulcanization is performed to co-melt the at least one layer of second reinforcing fibers with the surface portion of the conductive elastic matrix. Through secondary vulcanization, the elastic matrix continues to crosslink, achieving further fusion of the reinforcing fibers with the elastic matrix and increasing the overall stability and ease of operation of the polishing tool. Secondary vulcanization can be performed by a hot air oven or an infrared / continuous tunnel furnace.

[0039] Further, in step (3), the insulating elastic layer can be thickened by adding white carbon black to increase the wear resistance of the insulating elastic layer.

[0040] Further, after the laser engraving of step (4) is completed, deionized water or anhydrous ethanol is preferably used for ultrasonic cleaning (for example, 5 min) to remove debris and impurities, and then hot air is used for drying.

[0041] Further, in step (5), the electroplating treatment uses an electroplating solution that can include, for example, NiCl2·6H2O, H3BO3, sodium dodecyl sulfate, and the like, and the superhard abrasive particles can be sensitized-activated pretreated (sensitization: SnCl210 g / L + HCl 20 ml / L, ultrasonic at 45°C for 10 min; activation: PdCl20.2 g / L + HCl 10 ml / L, ultrasonic at room temperature for 5 min) and added with a surfactant (such as Tween-80) to be dispersed in the electroplating solution to improve the co-deposition rate.

[0042] After electroplating is completed, the elastic polishing tool is obtained after cleaning, drying, and appearance inspection.

[0043] The beneficial effects of the present application include:

[0044] 1. Controllable elasticity: The overall elasticity is adjusted by the proportion of the matrix material and the fibers, suitable for different curvature surfaces and meeting different precision machining requirements;

[0045] 2. Local hardness is prominent: The superhard abrasive particles electroplated in the micro-pits combined with the fiber reinforced area significantly improve the hardness and rigidity, with a hardness of HV 1500-2200 in the micro-pit area and Shore A 20-60 in the non-pit area, achieving "overall softness and local rigidity";

[0046] 3. Abrasive is firmly combined: the fiber is co-melted with the matrix, the electroplated abrasive is firmly combined with the fiber, and is not easy to fall off, and the abrasive falling rate is <2% after 5000 m of continuous polishing;

[0047] 4. High polishing precision: the hard points on the tool surface are uniformly distributed, the elastic matrix has strong buffering effect, and sub-micron level polishing precision can be achieved, and the material removal rate is ≥0.5 µm / min;

[0048] 5. Simple process and low cost: the laser engraving and electroplating process is mature and easy to control, and is suitable for batch production. BRIEF DESCRIPTION OF DRAWINGS

[0049] Figure 1 It is a schematic diagram of the basic structure of a composite elastic polishing tool for curved surface polishing in an embodiment of the present application.

[0050] Figure 2 It is a structural schematic diagram of the composite elastic polishing tool shaped into a wheel with a wheel core in an embodiment of the present application.

[0051] Figure 3 It is a structural schematic diagram of the composite elastic polishing tool shaped into a wheel with a wheel core in another embodiment of the present application.

[0052] Figure 4 It is a schematic diagram of the surface of the insulating elastic layer of the composite elastic polishing tool being patterned by laser engraving in an embodiment of the present application.

[0053] Figure 5 It is a process flow chart of the preparation method of the composite elastic polishing tool in an embodiment of the present application. DETAILED DESCRIPTION

[0054] In order to better understand the above technical solutions, the exemplary embodiments of the present application will be described in more detail below with reference to the accompanying drawings.

[0055] Although the exemplary embodiments of the present application are shown in the drawings, it should be understood that the present application can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided to enable a clearer, more thorough understanding of the present application and to fully convey the scope of the present application to those skilled in the art.

[0056] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "embodiment", "example", "specific example" or "some examples" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples. Furthermore, the person skilled in the art can combine and combine the different embodiments or examples described in the present specification and the features of the different embodiments or examples, without contradiction.

[0057] Embodiment 1

[0058] Referring to Figure 1 and Figure 5 , a schematic diagram showing the basic structure of a composite elastic polishing tool in an embodiment of the present application and a process flow diagram of a preparation method thereof are shown. The preparation method comprises the following process steps in sequence:

[0059] S1, preparing a conductive elastic matrix: mixing an elastic matrix raw material containing a conductive filler with a first reinforcing fiber, and then curing and forming to obtain a conductive elastic matrix 1;

[0060] S2, coating a second reinforcing fiber: coating at least one layer of a second reinforcing fiber 2 on the surface of the cured and formed conductive elastic matrix 1;

[0061] S3, coating an insulating elastic layer: coating an insulating elastic layer 3 on the second reinforcing fiber layer 2, and then heating and curing to form a dense layer;

[0062] S4, laser engraving to form micro-pits: patterning the surface of the insulating elastic layer 3 by laser engraving to form a plurality of regularly distributed micro-pits 6, the depth of the micro-pits 6 being greater than the thickness of the insulating elastic layer 3, so that the bottom of the micro-pits 6 exposes the conductive elastic matrix 1 and the first reinforcing fiber filled therein, and the sidewall of the micro-pits 6 exposes the second reinforcing fiber 2;

[0063] S5, electroplating to deposit abrasive particles: depositing superhard abrasive particles in the micro-pits 6 by electroplating, the superhard abrasive particles combining with the conductive elastic matrix 1, the first reinforcing fiber and the second reinforcing fiber 2 to form hard points.

[0064] As shown in Figures 2-3 , in addition to being formed into a planar or strip shape, the composite elastic polishing tool can also be formed into a wheel shape with a wheel core 5. In this way, the conductive elastic matrix 1 and the parts thereon are firmly attached to the wheel core 5 by providing a support part 4 on the inner side of the conductive elastic matrix 1, and the kinetic energy from the wheel core 5 is transmitted to drive the polishing tool to work. Figure 2 andFigure 3 The difference between wheel-shaped composite elastic polishing tools lies in the thickness of the wheel-shaped tool and the curvature of the polishing surface.

[0065] like Figure 4 As shown, in one embodiment of the present invention, a pattern of regularly arranged micro-pits 6 is formed on the surface of the insulating elastic layer 3 of the composite elastic polishing tool by laser engraving. The micro-pits 6 can have various shapes according to application needs, such as A-pentagon, B-triangle, C-ellipse, D-hexagon, E-circle, F-rectangle, and their depth, spacing and arrangement can also be flexibly set as needed.

[0066] The following composite elastic polishing tools (Examples 2-6) were prepared using the preparation method of Example 1.

[0067] Example 2

[0068] To produce a flat polishing disc.

[0069] The conductive elastic matrix is ​​made of conductive silicone rubber (100% silicone rubber, 20% 2-8μm nickel-copper powder), with an elastic modulus of 3 MPa and a thickness of 2 mm; it is filled with 10 wt% carbon fiber (2 mm in length and 20 μm in diameter) and coated with two layers of polyimide fiber cloth (Evonik P84). ® HT); coated with an elastic insulating layer (polyurethane coating) with a thickness of 50 μm relative to the upper polyimide fiber cloth, and cured at 90°C for 2 hours to form a dense layer.

[0070] A circular micro-pit array with a diameter of 80 μm, a depth of 100 μm, and a spacing of 50 μm was laser-engraved on a polyurethane coating. The micro-pit array was ultrasonically cleaned with anhydrous ethanol (5 min), and then a nickel-diamond (5 μm, 20 vol%) composite coating was electroplated in the micro-pits. After cleaning, drying, and visual inspection, the elastic polishing tool was obtained.

[0071] The resulting polishing tool has a uniform distribution of hard particles, making it suitable for precision polishing of optical glass lenses. The surface roughness Ra can be controlled to below 5 nm.

[0072] Example 3

[0073] Make a strip-shaped polishing belt.

[0074] The conductive elastic matrix is ​​made of conductive silicone rubber (100% silicone rubber, 15% 2-5μm nickel-plated aluminum powder), with an elastic modulus of 1 MPa, a thickness of 1 mm, and a width of 10 mm; it is filled with 5 wt% aramid fibers (1 mm in length and 10 μm in diameter), and coated with a layer of polyaramid fiber cloth (Kuraray Vectran). ®HT); coated with an elastic insulating layer (silicone rubber coating), 50 μm in thickness relative to the upper polyimide fiber cloth, cured at 100 °C for 3 h to form a dense layer.

[0075] A regular hexagonal micro-pit array was laser-engraved on the silicone rubber coating, with a side length of 50 μm, a depth of 80 μm, and a pitch of 100 μm; the micro-pit array was ultrasonically cleaned with anhydrous ethanol (5 min), and then a nickel-CBN (10 μm, 20 vol%) composite plating layer was electroplated in the micro-pits; after cleaning, drying, and appearance inspection, the elastic polishing tool was obtained.

[0076] The obtained polishing tool is suitable for finishing machining of the inner wall of a metal mold, has high abrasive bonding strength, and has an abrasive shedding rate of <2 % after 5000 m of continuous polishing.

[0077] Example 4

[0078] A polishing wheel of a wheel type was made.

[0079] The conductive elastic matrix was a conductive silicone rubber (100% silicone rubber, 30% 2-8 μm nickel-plated copper powder), with an elastic modulus of 6 MPa and a thickness of 5 mm; 20 wt% carbon fibers (length 3 mm, diameter 30 μm) were filled therein, and 3 layers of Nomex ® T-430) were coated on the surface; an elastic insulating layer (polyurethane coating) was coated, 80 μm in thickness relative to the upper polyimide fiber cloth, cured at 110 °C for 2 h to form a dense layer.

[0080] A pentagonal micro-pit array was laser-engraved on the polyurethane coating, with a side length of 60 μm, a depth of 100 μm, and a pitch of 60 μm; the micro-pit array was ultrasonically cleaned with anhydrous ethanol (5 min), and then a nickel-corundum (20 μm, 20 vol%) composite plating layer was electroplated in the micro-pits; after cleaning, drying, and appearance inspection, the elastic polishing tool was obtained.

[0081] The obtained polishing tool is suitable for high-speed polishing of a cemented carbide workpiece, has a material removal rate of ≥0.5 μm / min; and has an abrasive shedding rate of <2 % after 5000 m of continuous polishing.

[0082] Example 5

[0083] A polishing sheet of a planar type was made.

[0084] The conductive elastic matrix was a conductive elastic polymer (100% PDMS (Mn≥80k), 20% 2-6 μm silver-plated glass powder), with an elastic modulus of 5 MPa and a thickness of 3 mm; 8 wt% copper fibers (length 1 mm, diameter 20 μm) were filled therein, and 2 layers of Evonik P84 ®HT); coating an elastic insulating layer (polyurethane coating), 30 μm in thickness relative to the upper polyimide fiber cloth, cured at 90℃ for 1 h to form a dense layer.

[0085] An array of elliptical micro-pits with a long diameter of 20 μm, a short diameter of 10 μm, a depth of 40 μm, and a pitch of 30 μm was laser-engraved on the polyurethane coating; the array of micro-pits was ultrasonically cleaned with anhydrous ethanol (5 min), and then a nickel-diamond (0.5 μm, 30 vol%) composite plating layer was electroplated in the micro-pits; after cleaning, drying, and appearance inspection, the elastic polishing tool was obtained.

[0086] The obtained polishing tool is suitable for precision polishing of semiconductor wafers, and has excellent surface flatness, with a surface roughness Ra controllable to below 0.2 nm.

[0087] Example 6

[0088] A belt-shaped polishing belt was made.

[0089] The conductive elastic matrix was a conductive silicone rubber (100% silicone rubber, 30% silver-plated copper powder 5-10 μm), with an elastic modulus of 10 MPa, a thickness of 3 mm, and a width of 15 mm; 20 wt% carbon fibers (length 3 mm, diameter 20 μm) were filled therein, and the surface was coated with 4 layers of polyarylate fiber cloth (X-FIPER ® LCP-F); an elastic insulating layer (silicone rubber coating) was coated, 150 μm in thickness relative to the upper polyimide fiber cloth, cured at 120℃ for 4 h to form a dense layer.

[0090] An array of triangular micro-pits with a side length of 200 μm, a depth of 230 μm, and a pitch of 100 μm was laser-engraved on the silicone rubber coating; the array of micro-pits was ultrasonically cleaned with anhydrous ethanol (5 min), and then a nickel-CBN (20 μm, 20 vol%) composite plating layer was electroplated in the micro-pits; after cleaning, drying, and appearance inspection, the elastic polishing tool was obtained.

[0091] The obtained polishing tool is suitable for curved surface polishing of aero-engine blades, has high polishing efficiency, strong abrasive durability, and significantly reduces the risk of micro-cracks on the surface of the workpiece, with an abrasive shedding rate <2% after 5000 m of continuous polishing.

[0092] Although embodiments of the present application have been shown and described above, it should be understood that the above-described embodiments are exemplary, and are not to be construed as limiting the present application, and modifications, substitutions, replacements, and variations of the above-described embodiments can be made by those of ordinary skill in the art within the scope of the present application.

Claims

1. A composite elastic polishing tool for curved surface polishing, characterized in that, The composite elastic polishing tool includes a conductive elastic matrix and an insulating elastic layer. The conductive elastic matrix is ​​filled with a first reinforcing fiber, and the surface of the conductive elastic matrix is ​​covered with at least one layer of second reinforcing fiber. The insulating elastic layer is disposed on the second reinforcing fiber layer. The insulating elastic layer is laser-engraved to form a plurality of regularly distributed micro-pits. The depth of the micro-pits is greater than the thickness of the insulating elastic layer, so that the bottom of the micro-pit exposes the conductive elastic matrix and the first reinforcing fiber filled therein, and the sidewall of the micro-pit exposes the second reinforcing fiber. The micropits are deposited with superhard abrasive particles through electroplating. The superhard abrasive particles combine with the conductive elastic matrix, the first reinforcing fiber, and the second reinforcing fiber to form hard spots.

2. The composite elastic polishing tool for curved surface polishing according to claim 1, characterized in that, The conductive elastic matrix is ​​conductive rubber or conductive elastic polymer. The matrix of the conductive rubber is silicone rubber, fluororubber, EPDM rubber or nitrile rubber; the matrix of the conductive elastic polymer is thermoplastic polyurethane or high molecular weight polydimethylsiloxane.

3. The composite elastic polishing tool for curved surface polishing according to claim 2, characterized in that, The conductive elastic matrix has an elastic modulus of 0.1-16 MPa, a Shore hardness of 20-60 HA, and a volume resistivity of 10⁻⁶. -3 ~10 3 Ω·cm.

4. The composite elastic polishing tool for curved surface polishing according to claim 1, characterized in that, The first reinforcing fiber is at least one of metal fiber, carbon fiber, polyester fiber, aramid fiber, and glass fiber, and the filling ratio is 0.5 to 30 wt% of the mass of the conductive elastic matrix; the length of the first reinforcing fiber is 0.5-10 mm, the diameter is 10-50 µm, and the aspect ratio is 50-200.

5. The composite elastic polishing tool for curved surface polishing according to claim 1, characterized in that, The second reinforcing fiber is a polyimide fiber, a polyarylate fiber, or a meta-aramid fiber; the diameter of the second reinforcing fiber is 8-15 µm.

6. The composite elastic polishing tool for curved surface polishing according to claim 1, characterized in that, The elastic insulating layer is a flexible polyurethane or silicone rubber coating, and the thickness of the elastic insulating layer is 10-150 µm higher than the second reinforcing fiber layer.

7. The composite elastic polishing tool for curved surface polishing according to claim 1, characterized in that, The micropits are 10–200 μm in size, 20–300 μm deep into the conductive elastic matrix, and spaced 5–100 μm apart.

8. The composite elastic polishing tool for curved surface polishing according to claim 1, characterized in that, The superhard abrasive particles are diamond, cubic boron nitride, corundum, or SiC, with a particle size of 0.5–30 μm. A nickel-superhard abrasive particle composite coating is formed in the micro-pits by electroplating, thereby depositing the superhard abrasive particles in the micro-pits.

9. The composite elastic polishing tool for curved surface polishing according to claim 8, characterized in that, In the nickel-superhard abrasive particle composite coating, the volume fraction of the superhard abrasive particles is 5-50%.

10. A method for preparing a composite elastic polishing tool for curved surface polishing according to any one of claims 1-9, characterized in that, The method includes the following steps: (1) Preparation of conductive elastic matrix: The elastic matrix raw material containing conductive filler is mixed with the first reinforcing fiber and then cured to obtain conductive elastic matrix; (2) Coating with a second reinforcing fiber: Coating at least one layer of a second reinforcing fiber onto the surface of the cured conductive elastic matrix; (3) Coating an insulating elastic layer: an insulating elastic layer is coated on the second reinforcing fiber layer, and then heated and cured to form a dense layer; (4) Laser engraving to form micro-pits: Laser engraving is used to pattern the surface of the insulating elastic layer to form a number of regularly distributed micro-pits. The depth of the micro-pits is greater than the thickness of the insulating elastic layer, so that the bottom of the micro-pit exposes the conductive elastic matrix and the first reinforcing fiber filled therein, and the sidewall of the micro-pit exposes the second reinforcing fiber. (5) Electroplating deposited abrasive particles: superhard abrasive particles are deposited in micro pits by electroplating treatment, and the superhard abrasive particles are combined with the conductive elastic matrix, the first reinforcing fiber and the second reinforcing fiber to form hard particles.

Images