A composite grinding and polishing tool that combines grinding and polishing, its preparation method and use.

Abstract

This invention provides a combined grinding and polishing tool that achieves both grinding and polishing simultaneously, resulting in a product with fewer scratches, superior surface quality, high material removal rate, and a combination of high processing efficiency and excellent workpiece surface quality. [Solution] The composite grinding and polishing tool according to the present invention comprises a base layer and an abrasive layer, wherein a first abrasive and an organic composite microballoon pore-forming agent are fixed to the abrasive layer, and the organic composite microballoon pore-forming agent is a spherical or substantially spherical composite containing a second abrasive and a water-soluble binder, and the hardness of the second abrasive is less than or equal to the hardness of the first abrasive. The preparation method includes the steps of mixing the raw materials of the abrasive layer and putting them into a molding die, attaching the base layer and hardening it to obtain a composite grinding and polishing tool that combines grinding and polishing, or first hardening and demolding to obtain an abrasive layer, and then attaching the base layer to obtain a composite grinding and polishing tool that combines grinding and polishing.

Description

[Technical Field]

[0001] This invention belongs to the technical field of grinding and polishing, and more specifically relates to a composite grinding and polishing tool that performs both grinding and polishing, a method for preparing the same, and its use. [Background technology]

[0002] Hard and brittle materials such as sapphire, ceramics, glass, and silicon wafers play important roles in many fields, including electronics and information technology, defense and aerospace, due to their unique high strength, hardness, corrosion resistance, high temperature resistance, and wear resistance. With the development of cutting-edge technologies in fields such as aerospace and electronics and information technology, the demand for processing efficiency and surface quality of difficult-to-process materials such as silicon carbide, sapphire, ceramics, and specialty glass is increasing.

[0003] Currently, free abrasive processing technology is commonly used to polish the above materials. By using a polishing fluid containing abrasive particles in combination with an elastic polishing pad, good work surface quality can be obtained. However, the polishing process has the following problems: (1) Grinding and polishing tools cannot restrict the movement of abrasive particles, and the randomness of the distribution and movement of abrasive particles reduces processing efficiency and decreases uniformity within the wafer. (2) Because the abrasive material remains on the surface of the grinding and polishing tool for a relatively short time, the utilization rate of the abrasive material is low, and wastewater contamination is severe.

[0004] Currently, to solve the above problems, some conventional technologies employ fixed abrasive polishing techniques, fixing the abrasive material to the grinding and polishing tool to completely restrict the movement of the abrasive grains. This improves the uniformity of the abrasive distribution, material removal efficiency, and abrasive utilization rate. However, due to processing defects such as surface damage and scratches caused by friction with the abrasive material in the two-body wear mechanism, this technology cannot completely replace conventional free abrasive polishing techniques, and a finish polishing step with free abrasive material is still necessary after the fixed abrasive polishing step. Against this backdrop, the development of highly efficient precision machining technologies that combine processing efficiency and polishing quality is important. In view of this, the present invention is provided in particular. [Overview of the project] [Problems that the invention aims to solve]

[0005] The first objective of the present invention is to provide a combined grinding and polishing tool that can solve the problems of conventional free abrasive processing technology, which suffers from low processing efficiency, poor uniformity within the wafer, low utilization rate of abrasive material, and severe wastewater contamination, and the problems of fixed abrasive polishing technology, which suffers from severe scratches on the workpiece surface and still requires finish polishing with free abrasives after fixed abrasive polishing. The combined grinding and polishing tool according to the present invention simultaneously performs grinding and polishing, resulting in a product with fewer scratches, excellent surface quality, a high material removal rate, and a combination of high processing efficiency and good workpiece surface quality.

[0006] A second objective of the present invention is to provide a method for preparing a composite grinding and polishing tool that combines the functions of grinding and polishing.

[0007] The third object of the present invention is to provide a method for grinding and polishing a workpiece, which involves grinding and polishing the workpiece using the above-mentioned composite grinding and polishing tool that combines grinding and polishing.

[0008] To achieve the above-mentioned objectives of the present invention, the following technical solutions are particularly adopted. A composite grinding and polishing tool that combines grinding and polishing comprises a base layer and an abrasive layer, wherein a first abrasive and an organic composite microballoon pore-forming agent are fixed to the abrasive layer, and the organic composite microballoon pore-forming agent is a spherical or substantially spherical composite containing a second abrasive and a water-soluble binder, and the hardness of the second abrasive is less than or equal to the hardness of the first abrasive.

[0009] Preferably, by mass fraction, the abrasive layer contains: resin bond: 30% to 60%, first abrasive material: 3% to 20%, organic composite microballoon porosity agent: 3% to 35%, filler: 3% to 10%, and auxiliary agent: 0.2% to 15%.

[0010] Preferably, the particle size of the organic composite microballoon pore-forming agent is 20 to 90 μm. Preferably, in the organic composite microballoon pore-forming agent, the mass fraction of the water-soluble binder is 2.5% to 10%.

[0011] Preferably, the method for preparing the organic composite microballoon porosity agent is one of the following: centrifugal spray granulation, torsional granulation, or reverse-phase microemulsion polymerization.

[0012] Preferably, the water-soluble binder comprises at least one of cyclodextrin, dextrin, starch, methylolcellulose, methylcellulose, polyacrylic acid, polyacrylamide, and polyvinyl alcohol.

[0013] Preferably, the second abrasive material contains at least one of aluminum oxide, silicon dioxide, and cerium oxide. Preferably, the Mohs hardness of the second abrasive material is 6 to 9. Preferably, the particle size of the second abrasive material is 100 to 500 nm.

[0014] Preferably, the first abrasive material includes at least one of diamond, silicon carbide, cubic boron nitride, zirconium oxide, and corundum. Preferably, the Mohs hardness of the first abrasive material is 7 to 10. Preferably, the particle size of the first abrasive material is 20 to 500 nm. Preferably, the median diameter of the second abrasive material is equal to or greater than the median diameter of the first abrasive material.

[0015] Preferably, the resin bond comprises at least one of unsaturated polyester, epoxy resin, and polyurethane.

[0016] Preferably, the filler includes one or a combination of several of the following: graphite, carbon black, short carbon fibers, carbon nanotubes, calcium carbonate, and calcium silicate.

[0017] Preferably, the auxiliary agent contains at least one of an initiator, a curing agent, and a dispersant.

[0018] The method for preparing the composite grinding and polishing tool that combines grinding and polishing is as follows: Step S1 of mixing the raw materials of the abrasive layer, defoaming to obtain a mixed material, and putting the mixed material into a molding die; Step S2 of attaching the substrate layer to the surface of the mixed material that is not the grinding and polishing surface, undergoing curing to obtain a composite grinding and polishing tool that combines grinding and polishing, or first curing the mixed material to obtain an abrasive layer, and then attaching the substrate layer to the surface of the abrasive layer that is not the grinding and polishing surface to obtain a composite grinding and polishing tool that combines grinding and polishing.

[0019] The method for grinding and polishing a workpiece is to perform grinding and polishing on the workpiece using the above-mentioned composite grinding and polishing tool that combines grinding and polishing.

Advantages of the Invention

[0020] Compared with the prior art, the present invention has the following beneficial effects. (1) The composite grinding and polishing tool that combines grinding and polishing according to the present invention has a first abrasive and an organic composite microballoon pore-forming agent fixed to the abrasive layer. In the process of machining the workpiece, the first abrasive serves as a fixed abrasive to grind the workpiece and increase the material removal rate. The organic composite microballoon pore-forming agent on the surface layer meets the aqueous grinding fluid on the surface of the grinding and polishing tool during the machining process of the workpiece, and the water-soluble binder physically dissolves to form an open pore structure on the surface of the grinding and polishing tool, which contains a second abrasive that is free and distributed in the pore structure. On the one hand, as a pore-forming agent, the organic composite microballoon pore-forming agent increases the chip accommodation space inside the grinding and polishing tool and reduces the hardness of the substrate of the grinding and polishing tool, thereby reducing the scratches on the workpiece surface and improving the self-generated cutting edge property of the grinding and polishing tool. On the other hand, a free abrasive grain component is introduced into the composite grinding and polishing tool to polish the workpiece and improve the surface quality of the material. Grinding and polishing processes are simultaneously realized, and the obtained product has few scratches, excellent surface quality, high material removal rate, and can combine high processing efficiency and good workpiece surface quality.

[0021] (2) If grinding and polishing are performed on the workpiece surface using the composite grinding and polishing tool that combines grinding and polishing according to the present invention, compared with the conventional free abrasive grain polishing technology, the consumption of the abrasive is less, and the waste liquid pollution can be reduced. Compared with the conventional fixed abrasive grain processing technology, the machined workpiece has few scratches and excellent surface quality, and further finishing polishing treatment is not required.

Brief Description of the Drawings

[0022] To more clearly explain the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the specific embodiments or the prior art will be briefly described below. The drawings to be described only show some embodiments of the present invention. Those skilled in the art can obtain other drawings based on these drawings without using inventive capabilities.

[0023] [Figure 1] It is a schematic diagram of the preparation process of the organic composite microballoon pore-forming agent according to an embodiment of the present invention. [Figure 2]This is a schematic diagram showing the molding process of a composite grinding and polishing tool that combines grinding and polishing according to an embodiment of the present invention. [Figure 3] This is a schematic diagram of a working surface for a composite grinding and polishing tool that combines grinding and polishing according to an embodiment of the present invention. [Figure 4] This illustrates the grinding mechanism of a composite grinding and polishing tool that combines grinding and polishing according to an embodiment of the present invention. [Figure 5] These are photographs of the surface morphology of a composite grinding and polishing tool that combines grinding and polishing according to an embodiment of the present invention. (Of these photographs, the leftmost one shows the entire surface of the composite grinding and polishing tool, the middle one shows the pores formed on the surface of the composite grinding and polishing tool by an organic composite microballoon pore-forming agent, and the rightmost one shows the second abrasive material that is free and distributed within the pores.) [Figure 6] This is a schematic diagram showing the working process of a grinding and polishing apparatus according to an embodiment of the present invention. [Modes for carrying out the invention]

[0024] The technical aspects of the present invention will be clearly and completely described below with reference to the drawings and specific embodiments. As those skilled in the art will see, the embodiments described are only some embodiments of the present invention, not all embodiments, and are merely for illustrative purposes and do not limit the scope of the present invention. All other embodiments obtained by those skilled in the art without using their inventive ability based on the embodiments of the present invention are also within the scope of the protection of the present invention. Where specific conditions are not specified in the embodiments, it is possible to carry them out under conventional conditions or conditions recommended by the manufacturer. Where the manufacturer of the preparation is not specified, it is possible to use commercially available conventional products.

[0025] The first aspect of the present invention provides a composite grinding and polishing tool that combines grinding and polishing. The composite grinding and polishing tool comprises a base layer and an abrasive layer, with a first abrasive and an organic composite microballoon pore-forming agent fixed to the abrasive layer, wherein the organic composite microballoon pore-forming agent is a spherical or substantially spherical composite containing a second abrasive and a water-soluble binder, and the hardness of the second abrasive is less than or equal to the hardness of the first abrasive.

[0026] Conventional technologies have problems such as low processing efficiency, poor uniformity within the wafer, low utilization rate of abrasive material, and severe wastewater contamination in free abrasive processing technology, and severe scratches on the workpiece surface in fixed abrasive processing technology. In contrast, the composite grinding and polishing tool according to the present invention combines the advantages of both fixed abrasive processing and free abrasive processing, achieving grinding and polishing simultaneously. The result is a workpiece with fewer scratches, superior surface quality, a high material removal rate, and a combination of high processing efficiency and good workpiece surface quality.

[0027] As shown in Figures 3 and 5, the present invention has a first abrasive material and an organic composite microballoon porosizing agent fixed to an abrasive layer. The first abrasive material plays the role of grinding the workpiece as a fixed abrasive material to increase the material removal rate. The organic composite microballoon porosizing agent on the surface of the composite grinding and polishing tool comes into contact with the aqueous grinding fluid on the surface of the grinding and polishing tool during the workpiece processing process, causing the water-soluble binder to dissolve and form an open pore structure on the surface of the grinding and polishing tool, which contains a second abrasive material that is free and distributed within the pore structure. On the one hand, as a porosizing agent, the organic composite microballoon porosizing agent increases the debris containment space inside the grinding and polishing tool, lowers the hardness of the base of the grinding and polishing tool, thereby reducing scratches on the workpiece surface and improving the self-sharpening ability of the grinding and polishing tool. On the other hand, the composite grinding and polishing tool plays the role of releasing free abrasive particles in place during the working process to polish the workpiece and improve the surface quality of the material. As a result, grinding and polishing are achieved simultaneously.

[0028] By ensuring that the hardness of the first abrasive material is greater than or equal to that of the second abrasive material, and using the first abrasive material, which has relatively high hardness, as a fixed abrasive for grinding, while using the second abrasive material, which has relatively low hardness, as a free abrasive for polishing, it is possible to guarantee both relatively high grinding efficiency and workpiece surface quality.

[0029] In some specific embodiments of the present invention, the first abrasive material and the organic composite microballoon porosizing agent are uniformly distributed in the abrasive layer.

[0030] In some specific embodiments of the present invention, the abrasive layer comprises, by mass fraction, resin bond: 30% to 60%, first abrasive material: 3% to 20%, organic composite microballoon porosizing agent: 3% to 35%, filler: 3% to 10%, and auxiliary agent: 0.2% to 15%.

[0031] The resin bond plays a crucial role in fixing components such as the primary abrasive, organic composite microballoon porosity agent, and filler, and is essential for receiving and transmitting loads in composite grinding and polishing tools, and for maintaining the environment of the grinding and polishing fluid. The filler plays a role in increasing the strength of the grinding layer, and the auxiliary agents mainly play a role in initiating reactions, improving the degree of crosslinking of the resin system, or promoting the dispersion of components.

[0032] In some embodiments, representative and non-limiting, for example, in the abrasive layer, the mass content of the resin bond is any value from among 30%, 35%, 39%, 45%, 52%, 55%, and 60%, or within the range of any two values; the mass content of the first abrasive is any value from among 3%, 5%, 8%, 11%, 15%, 18%, and 20%, or within the range of any two values; and the mass content of the organic composite microballoon pore-forming agent is 3%, 5%. The mass content of the filler is any value from among %, 10%, 15%, 20%, 25%, 28%, 31%, and 35%, or a value within the range of any two values. The mass content of the auxiliary is any value from among 3%, 4%, 5%, 6%, 7%, 8%, 9%, and 10%, or a value within the range of any two values. The mass content of the auxiliary is any value from among 0.2%, 0.5%, 1%, 1.5%, 2%, 3%, 5%, 8%, 10%, 12%, and 15%, or a value within the range of any two values.

[0033] In some specific embodiments of the present invention, the particle size of the organic composite microballoon pore-forming agent is 20 to 90 μm, for example, any value from 20 μm, 25 μm, 32 μm, 38 μm, 45 μm, 50 μm, 60 μm, 70 μm, 80 μm, and 90 μm, or a value within the range of any two of these values. If the particle size of the organic composite microballoon pore-forming agent is too small, the sieving equipment cannot accurately control the particle size of the pore-forming agent during preparation, and the diameter of the open holes formed on the surface of the grinding and polishing tool during the workpiece processing process is too small, resulting in a reduced effect on workpiece polishing, improvement of material surface quality, and improvement of the self-sharpening ability of the grinding and polishing tool. If the particle size of the organic microballoon pore-forming agent is too large, the structural stability of the grinding and polishing surface of the grinding and polishing tool is easily impaired, and the stability of the grinding and polishing effect cannot be guaranteed. Therefore, it is necessary to rationally control the particle size range of the organic composite microballoon pore-forming agent.

[0034] In some specific embodiments of the present invention, in the organic composite microballoon pore-forming agent, the mass fraction of the water-soluble binder is 2.5% to 10%, and is, for example, any value among 2.5%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, and 10%, or a value within the range of any two of these values.

[0035] If the water-soluble binder content in an organic composite microballoon pore-forming agent is too low, the secondary abrasive material tends to become loose, making it difficult for it to bind and aggregate into spherical shapes. If the water-soluble binder content is too high, the secondary abrasive material content in the organic composite microballoon pore-forming agent tends to be too low, resulting in insufficient abrasive material content in the open pores of the composite grinding and polishing tool, and thus a weak polishing effect from the free abrasive material. Therefore, it is necessary to rationally control the composition and content of the organic composite microballoon pore-forming agent.

[0036] As shown in Figure 1, in some specific embodiments of the present invention, the method for preparing an organic composite microballoon pore-forming agent is a centrifugal spray granulation method, which includes the following steps.

[0037] A second abrasive material, a water-soluble binder, and water are mixed and dispersed to obtain an aqueous dispersion in which the mass fraction of the second abrasive material is 10% to 35%. The aqueous dispersion is then granulated and sieved using centrifugal spray granulation technology to obtain an organic composite microballoon pore-forming agent.

[0038] In some specific embodiments of the present invention, when preparing an aqueous dispersion, the method of mixed dispersion includes shear dispersion and / or ultrasonic dispersion.

[0039] In some specific embodiments of the present invention, granulation is performed in a centrifugal spray dryer, where the liquid inlet rate of the aqueous dispersion is 10 to 40 ml / min, the air inlet temperature is 160 to 250°C, and the centrifugal frequency is 200 to 400 Hz.

[0040] In some embodiments, as representative and non-limiting examples, the mass fraction of the second abrasive material in the aqueous dispersion is any value from among 10%, 15%, 20%, 25%, 30%, and 35%, or within the range of any two values; the immersion rate of the aqueous dispersion is any value from among 10ml / min, 20ml / min, 30ml / min, and 40ml / min, or within the range of any two values; the air inlet temperature is any value from among 160°C, 180°C, 200°C, 210°C, 230°C, and 250°C, or within the range of any two values; and the centrifugal frequency is any value from among 200Hz, 220Hz, 250Hz, 280Hz, 300Hz, 320Hz, 350Hz, 380Hz, and 400Hz, or within the range of any two values.

[0041] If the aqueous dispersion concentration is too high (or too low), the liquid injection rate is too fast (or too slow), or the centrifugal frequency is too low (or too high), it can lead to the particle size of the organic composite microballoon pore-forming agent being too large (or too small). If the air intake temperature is too low, the organic composite microballoon pore-forming agent cannot dry completely, and the particles tend to bind together and form clumps. If the air intake temperature is too high, thermal decomposition of the water-soluble binder occurs, the water dries too quickly, the microballoons break down, and the shape of the pore-forming agent is easily disrupted.

[0042] In some other embodiments of the present invention, the organic composite microballoon porosity agent may be prepared by other methods such as torch granulation or reverse-phase microemulsion polymerization.

[0043] In some specific embodiments of the present invention, the water-soluble binder comprises at least one of cyclodextrin, dextrin, starch, methylolcellulose, methylcellulose, polyacrylic acid, polyacrylamide, and polyvinyl alcohol. The water-soluble binder plays a role in bonding the second abrasive material in the preparation of organic composite microballoon pore-forming agents and composite grinding and polishing tools.

[0044] In some specific embodiments of the present invention, the second abrasive material comprises at least one of aluminum oxide, silicon dioxide, and cerium oxide.

[0045] In some specific embodiments of the present invention, the Mohs hardness of the second abrasive material is 6 to 9, for example, 6, 7, 8, or 9.

[0046] In some specific embodiments of the present invention, the particle size of the second abrasive material is 100 to 500 nm, for example, any value among 100 nm, 200 nm, 300 nm, 400 nm, and 500 nm, or a value within the range of any two of these values.

[0047] In some specific embodiments of the present invention, the first abrasive material comprises at least one of diamond, silicon carbide, cubic boron nitride, zirconium oxide, and corundum, wherein the diamond may be one or a combination of single crystal, polycrystalline, or similar polycrystalline forms.

[0048] In some specific embodiments of the present invention, the Mohs hardness of the first abrasive material is 7 to 10, for example, 7, 8, 9, or 10.

[0049] In some specific embodiments of the present invention, the particle size of the first abrasive material is 20 to 500 nm, for example, any value among 20 nm, 100 nm, 200 nm, 300 nm, 400 nm, and 500 nm, or a value within the range of any two of these values.

[0050] In some specific embodiments of the present invention, the median diameter of the second abrasive material is greater than or equal to the median diameter of the first abrasive material, thereby contributing to an improved polishing effect.

[0051] In some specific embodiments of the present invention, the resin bond comprises at least one of unsaturated polyesters, epoxy resins, and polyurethanes, such as epoxy acrylate, polyethylene glycol acrylate, urethane acrylate, bisphenol A type epoxy resin, bisphenol F type epoxy resin, polyphenol glycidyl ether type epoxy resin, aliphatic glycidyl ether epoxy resin, glycidyl ester type epoxy resin, polyester polyurethane, and polyether type polyurethane.

[0052] In some specific embodiments of the present invention, the filler comprises one or more of the following: graphite, carbon black, short carbon fibers, carbon nanotubes, calcium carbonate, and calcium silicate, and primarily serves to increase the strength of the abrasive layer.

[0053] In some specific embodiments of the present invention, the auxiliary agent includes at least one of an initiator, a curing agent, and a dispersant. For example, initiators include azobisisobutyronitrile, dibenzoyl peroxide, tetraphenylethanediol, tetraphenylsuccinonitrile, initiator 184, initiator 1173, initiator TPO, or initiator 819, and play a role in initiating the polymerization reaction of unsaturated polyester systems. Curing agents include aliphatic amines, aromatic amines, acid anhydrides, isocyanate curing agents, polyvalent hydroxy curing agents, and play a role in improving the degree of crosslinking of resin systems and promoting the hardening and shape fixing of grinding and polishing tools. Dispersants include silane coupling agents KH550, KH560, KH570, and play a role in increasing the interfacial adhesion strength of abrasives, fillers, and binders and promoting the uniform dispersion of components.

[0054] In some specific embodiments of the present invention, the substrate layer is a polymer sheet material, for example, the polymer of the substrate layer is carbon fiber, PET, PC, PMMA, PS, PI, epoxy resin, phenolic resin, polyurethane, rubber elastomer, or silicone elastomer.

[0055] As shown in Figure 2, a second aspect of the present invention provides a method for preparing a composite grinding and polishing tool that combines grinding and polishing according to any one of the embodiments described above. The preparation method includes the following steps.

[0056] S1: The raw materials for the abrasive layer are mixed and degassed to obtain a mixed material, and the mixed material is placed into a molding die having a specific shape.

[0057] S2: A composite grinding and polishing tool is obtained by attaching a base layer to the non-grinding / polishing surface of the mixed material and allowing it to harden to perform both grinding and polishing. Alternatively, the mixed material is first hardened and released to obtain an abrasive layer, and then a base layer is attached to the non-grinding / polishing surface of the abrasive layer to obtain a composite grinding and polishing tool that performs both grinding and polishing.

[0058] The method according to the present invention has a simple preparation process, and the prepared grinding and polishing tool allows for simultaneous grinding and polishing. The resulting product has fewer scratches, excellent surface quality, a high material removal rate, and combines high processing efficiency with good workpiece surface quality, thus combining the advantages of both free abrasive and fixed abrasive processing.

[0059] In some specific embodiments of the present invention, the curing method is photocuring or thermocuring.

[0060] In some specific embodiments of the present invention, photocuring is performed when the ultraviolet light intensity is 500-1500 mW / cm². 2 For example, 500 mW / cm² 2 750mW / cm² 2 , 1000mW / cm 2 , 1250mW / cm 2 , 1500mW / cm 2 The irradiation time is any value from among these, or a value within the range of any two values, and the irradiation time is 20 to 120 s, for example, any value from among 20 s, 40 s, 60 s, 80 s, 100 s, and 120 s, or a value within the range of any two values.

[0061] In some specific embodiments of the present invention, the substrates are bonded together with an organic adhesive or a double-sided adhesive, and in the case of a grinding and polishing tool comprising multiple different substrate layers, the different substrate layers can be bonded together with an organic adhesive or a double-sided adhesive.

[0062] In some specific embodiments of the present invention, the organic adhesive may be one or more types of hot-melt adhesives or reactive adhesives, such as epoxy resin adhesives, polyurethane resin adhesives, polyimide adhesives, silicone adhesives, acrylate adhesives, acrylic acid adhesives, and the like.

[0063] In some specific embodiments of the present invention, the double-sided adhesive is a resin-based hot-melt adhesive and / or a pressure-sensitive adhesive.

[0064] A third aspect of the present invention provides a method for grinding and polishing a workpiece. This grinding and polishing method involves grinding and polishing a workpiece using a composite grinding and polishing tool that combines grinding and polishing according to any one of the above embodiments. The composite grinding and polishing tool is used in combination with an aqueous grinding fluid during the grinding and polishing process of the workpiece, forming open holes containing a second abrasive material on the surface layer. As the composite grinding and polishing tool wears down, the second abrasive material is released from top to bottom in layers.

[0065] In some specific embodiments of the present invention, the material of the workpiece to be processed may be a brittle material that is difficult to process, such as silicon carbide, sapphire, ceramics, or special glass.

[0066] In some specific embodiments of the present invention, the aqueous grinding fluid used consists of components such as water, an oxidizing agent, a pH adjuster, and a catalyst. Water is the main substance of the grinding fluid, providing a liquid environment during the processing process, dissolving the pore-forming agent to form pores, and removing processing heat from the system, with a mass fraction of 80% to 98%. The oxidizing agent is potassium permanganate, which forms a relatively soft oxidation reaction layer on the surface of silicon carbide through oxidation reactions, thereby reducing the hardness of the workpiece being processed, with a mass fraction of 1% to 20%. The pH adjuster is one or more of the following: hydrochloric acid, sulfuric acid, nitric acid, acetic acid, sodium hydroxide, potassium hydroxide, aqueous ammonia, trimethylammonium hydroxide, etc., which adjusts the pH of the grinding fluid and controls the oxidizing power of potassium permanganate, with the system's pH typically being 4 to 6 or 9 to 11. The catalyst is manganese dioxide, which is added during the preparation of the grinding fluid or provided as a product of the oxidative decomposition of potassium permanganate. It plays a role in accelerating and regulating the rate of the oxidation reaction, and the mass fraction of manganese dioxide added is usually 0-2%.

[0067] As shown in Figure 4, the working principle for grinding and polishing a workpiece using the above-mentioned composite grinding and polishing tool is as follows: During the grinding and polishing process, the oxidizing agent in the aqueous grinding fluid reacts chemically with the surface of the workpiece through catalytic action, generating a softened film layer that is less hard than the workpiece. The water-soluble binder in the organic microballoon pore-forming agent on the surface of the grinding and polishing tool dissolves upon contact with water, forming spherical or approximately spherical open pores on the surface of the composite grinding and polishing tool, which contain a second abrasive material that is free and distributed within the pores. The first and second abrasive materials in the abrasive layer play a mechanical removal role from the softened film layer on the workpiece surface. The first abrasive material is harder than the second abrasive material and mainly plays a role in material removal, while the second abrasive material mainly plays a polishing role.

[0068] Several embodiments of the present invention will be described in detail below using specific examples. Unless otherwise specified, the raw materials used in the examples are commercially available.

[0069] In each of Examples 1 to 8, the first abrasive material is d 50 The particle size is 200 nm, the organic composite microballoon pore-forming agent has a particle size of 32-38 μm, and is prepared by centrifugal spray granulation, and the second abrasive material is d 50 The particle size is 250 nm. The median diameter of the filler used is 0.5 μm. The unsaturated polyester used is a mixture of prepolymer PEG400DA and a crosslinking agent. The epoxy resin is polyurethane-modified epoxy resin UME308. The polyurethane is a mixture of polyester-based polyurethane prepolymer and diethylenetriamine. The dispersant used in the unsaturated polyester system is KH570. The dispersant used in the epoxy resin system is KH560. The dispersant used in the polyurethane system is KH550. The composition of the abrasive layers in Examples 1 to 8 is shown in Table 1.

[0070] [Table 1]

[0071] Example 1 Table 1 shows the composition of the abrasive layer in this embodiment. A PET sheet material with a thickness of 0.15 mm was used for the base layer. The preparation method for the composite grinding and polishing tool, which combines grinding and polishing, was as follows.

[0072] S1: The raw materials for the abrasive layer, weighed in the proportions shown in Table 1, were uniformly mixed, degassed, and then poured into a molding die having a specific shape. S2: The molding die was placed in a blow-air oven and molded and cured using a thermosetting method. In the curing process, it was heated at 80°C for 2 hours, then at 100°C for 2 hours, then at 120°C for 1 hour to cure and release the mold to obtain an abrasive layer. A PET substrate layer was attached to the non-grinding surface of the abrasive layer with double-sided adhesive to obtain a composite grinding and polishing tool that combines grinding and polishing.

[0073] Example 2 Table 1 shows the composition of the abrasive layer in this embodiment. A PET sheet material with a thickness of 0.15 mm was used for the base layer. The method for preparing the composite grinding and polishing tool, which combines grinding and polishing, was the same as in Example 1.

[0074] Example 3 Table 1 shows the composition of the abrasive layer in this embodiment. A polyurethane sheet material with a thickness of 0.2 mm was used for the base layer. The preparation method for the composite grinding and polishing tool, which combines grinding and polishing, was as follows.

[0075] S1: The raw materials for the abrasive layer, weighed in the proportions shown in Table 1, were uniformly mixed, degassed, and then poured into a molding die having a specific shape. S2: The molding die was placed in a blow-air oven and molded and cured using a thermosetting method. In the curing process, it was heated at 80°C for 2 hours, then at 100°C for 2 hours, then at 140°C for 2 hours to cure and release the mold to obtain an abrasive layer. A polyurethane substrate layer was attached to the non-grinding surface of the abrasive layer with double-sided adhesive to obtain a composite grinding and polishing tool that combines grinding and polishing.

[0076] Example 4 Table 1 shows the composition of the abrasive layer in this embodiment. A polyurethane sheet material with a thickness of 0.2 mm was used for the base layer. The method for preparing the composite grinding and polishing tool, which combines grinding and polishing, was the same as in Example 3.

[0077] Example 5 Table 1 shows the composition of the abrasive layer in this embodiment. A PC sheet material with a thickness of 0.15 mm was used for the base layer. The preparation method for the composite grinding and polishing tool, which combines grinding and polishing, was as follows.

[0078] S1: The raw materials for the abrasive layer, weighed in the proportions shown in Table 1, were uniformly mixed, degassed, and then poured into a molding die having a specific shape. S2: Attach the PC base layer sheet material to the surface of the molding material that is not the grinding and polishing surface, degas it again, put the molding die into a blowing oven, go through programmed baking and curing, and then demold to obtain a composite grinding and polishing tool that combines grinding and polishing. The curing process was baking at 60 °C for 30 minutes.

[0079] Example 6 The composition of the abrasive layer in this example is shown in Table 1. A PC sheet material with a thickness of 0.15 mm was used for the base layer. The method for preparing the composite grinding and polishing tool that combines grinding and polishing was the same as that in Example 5.

[0080] Example 7 The composition of the abrasive layer in this example is shown in Table 1. A PET sheet material with a thickness of 0.15 mm was used for the base layer. The method for preparing the composite grinding and polishing tool that combines grinding and polishing was as follows.

[0081] S1: Uniformly mix the raw materials of the abrasive layer weighed at the ratios shown in Table 1, degas them, and pour them into a molding die with a specific shape. S2: Attach the PET base layer sheet material to the surface of the molding material that is not the grinding and polishing surface, degas it again, go through curing by a photocuring process, and then demold to obtain a composite grinding and polishing tool that combines grinding and polishing. The photocuring process was irradiated with ultraviolet light of intensity 1000 mW / cm 2 for 80 seconds.

[0082] Example 8 The composition of the abrasive layer in this example is shown in Table 1. A PET sheet material with a thickness of 0.15 mm was used for the base layer. The method for preparing the composite grinding and polishing tool that combines grinding and polishing was the same as that in Example 7.

[0083] Comparative Example 1 Comparative Example 1 is similar to Example 1 and is different from Example 1 only in the following points. In Comparative Example 1, an organic composite microballoon pore-forming agent was not added to the abrasive layer, and the ratios of the other components remained unchanged. The base layer used and the method for preparing the grinding and polishing tool were the same as those in Example 1.

[0084] Comparative Example 2 Comparative Example 2 is similar to Example 3, differing only in the following respects: In Comparative Example 2, the organic composite microballoon pore-forming agent was not added to the abrasive layer, and the proportions of the other components remained unchanged. The preparation methods for the substrate layer and grinding / polishing tools used were the same as in Example 3.

[0085] Comparative Example 3 Comparative Example 3 is similar to Example 5, differing only in the following respects: In Comparative Example 3, the organic composite microballoon pore-forming agent was not added to the abrasive layer, and the proportions of the other components remained unchanged. The preparation method for the substrate layer and grinding / polishing tools used was the same as in Example 5.

[0086] Comparative Example 4 Comparative Example 4 is similar to Example 1, differing only in the following respects: an equal amount of dextrin (with a dextrin content of 25 wt% and an aluminum oxide content of 0%) was used instead of aluminum oxide, and dextrin microballoons without a second abrasive were used instead of the organic composite microballoon pore-forming agent used in Example 1. All other conditions were the same as in Example 1.

[0087] Comparative Example 5 Comparative Example 5 is similar to Example 1, differing only in the following respects: an equal amount of aluminum oxide (with 0% dextrin content and 25 wt% aluminum oxide content) was used instead of dextrin, a second abrasive material was used instead of the organic composite microballoon pore-forming agent used in Example 1, and all other conditions were the same as in Example 1.

[0088] Comparative Example 6 Comparative Example 6 is similar to Example 1, differing only in the following respects: Dextrin (water-soluble binder) and aluminum oxide (second abrasive material) were not granulated; the content of each component was the same as in Example 1; all raw materials were directly mixed to prepare the composite grinding and polishing tool; and all other conditions were the same as in Example 1.

[0089] Test example (1) Measurement of density, hardness in a dry state, and pore size on the surface of grinding and polishing tools. For each example and comparative example, the density of the abrasive layer and the hardness in a dry state were measured for the composite grinding and polishing tools prepared. In addition, the pore diameter of the holes formed on the surface of the composite grinding and polishing tools by the dissolution of the water-soluble binder in the organic composite microballoon pore-forming agent was measured.

[0090] The density was measured using a density measuring device, with kerosene as the liquid medium. In the dry state, the hardness was measured using a Shore C hardness tester, assuming that the water-soluble binder in the organic microballoon pore-forming agent on the surface of the abrasive layer had not dissolved. Pore ​​size was determined by dissolving the water-soluble binder in the organic composite microballoon pore-forming agent on the surface layer of the abrasive material in water, drying it, and storing it at room temperature for 24 hours. Pore size data was measured by SEM, and 20 pore size data points within the same area were measured and averaged. The measurement results are shown in Table 2.

[0091] [Table 2]

[0092] As can be seen from the data in Table 2, when no pores are formed inside the dry abrasive layer, and the density of the abrasive layer is related to the compositional mixing ratio, and the proportions of other components do not change significantly, the change in the density of the abrasive layer of a grinding and polishing tool to which an organic microballoon pore-forming agent is added is mainly influenced by the type and content of each component in the organic microballoon pore-forming agent. As can be seen from Example 1 and Comparative Example 6, when the composition is the same, there is not a large difference in the density of the abrasive layer between a composite grinding and polishing tool prepared with an organic composite microballoon pore-forming agent added and a grinding and polishing tool prepared by mixing all raw materials (without granulation).

[0093] As can be seen from the comparison between Example 1 and Comparative Example 1, Example 3 and Comparative Example 2, and Example 5 and Comparative Example 3, the introduction of the organic composite microballoon pore-forming agent in the examples slightly reduced the hardness of the abrasive layer. As can be seen from the comparison between Example 1 and Examples 7-8, reducing the proportion of the first abrasive and increasing the proportion of the organic composite microballoon pore-forming agent significantly reduced the hardness of the abrasive layer.

[0094] As can be seen from Examples 1 to 8, the size of the pores on the surface of the abrasive layer was close to the diameter of the organic composite microballoon pore-forming agent, and the pore size on the surface of the abrasive layer obtained by this method was relatively uniform.

[0095] (2) Grinding and polishing performance test In the grinding and polishing process, the grinding and polishing tools of Examples 1, 3, 5, 7, 8 and Comparative Examples 1-6 were used in combination with a grinding and polishing fluid without abrasive material (KMnO4 polishing fluid, pH = 5.2-5.8).

[0096] Comparative Example 7 describes an example in which SUBA800 was used as a polishing pad, and a silicon dioxide polishing solution with a particle size of 250 nm (pH = 10.0-10.5, solid content of abrasive material: 2 wt%) was also used in combination to perform free abrasive processing.

[0097] Comparative Example 8 describes an example in which free abrasive grains were processed using SUBA800 as a polishing pad, in combination with a diamond polishing solution with a particle size of 200 nm (KMnO4 polishing solution, pH = 5.2~5.8, solid content of abrasive material: 2 wt%).

[0098] The measurement process is shown in Figure 6. The grinding and polishing tools according to Examples 1, 3, 5, 7, and 8 and Comparative Examples 1-8 were fixed to a rotating disc, a 4-inch SiC single crystal wafer was fixed to a workpiece holding means (with the Si side facing downwards), the grinding and polishing fluid was supplied by a liquid supply device, and other processing process parameters are shown in Table 3.

[0099] [Table 3]

[0100] As indicators for evaluating the grinding and polishing effect, the average material removal rate, surface roughness, wafer non-uniformity, and average abrasive material consumption rate were measured for each example and comparative example during the grinding and polishing process.

[0101] The average material removal efficiency was calculated using mass spectrometry. Surface roughness was measured using a white light interferometer.

[0102] Measurement of wafer non-uniformity: Seventeen points were selected evenly along two perpendicular diameters on the processed surface of the wafer, from one edge through the center to the other, and the thickness H was measured. Formula: Non-uniformity = (H max -H min ) / (2×H 平均 ) × 100%.

[0103] Method for calculating the average abrasive wear rate: In Examples 1, 3, 5, 7, 8 and Comparative Examples 1-6, the average abrasive wear rate = amount of abrasive material consumed by the prepared grinding / polishing tool ÷ lifespan of the grinding / polishing tool. In Comparative Examples 7-8, the average abrasive wear rate = polishing fluid flow rate × polishing fluid density × mass fraction of abrasive material in the polishing fluid. The measurement results are shown in Table 4.

[0104] [Table 4]

[0105] As can be seen from the data shown in Table 4, the composite grinding and polishing tools prepared according to the embodiments of the present invention (Examples 1, 3, and 5) have a higher average material removal rate and lower workpiece surface roughness compared to grinding and polishing tools (Comparative Examples 1-3) that do not contain the organic composite microballoon pore-forming agent but have the same other composition, thus achieving both processing efficiency and surface quality. As can be seen from the comparison between Example 1 and Comparative Examples 4-6, the processing effect according to the present invention is related to the introduction of the organic composite microballoon pore-forming agent, and a similar processing effect cannot be obtained by simply mixing some or all of the raw materials of the organic composite microballoon pore-forming agent in the abrasive layer. In other words, even if the composition is the same, if a grinding and polishing tool is prepared by simply mixing the second abrasive material and water-soluble binder with other raw materials directly, without pre-granulating the second abrasive material and water-soluble binder to prepare the organic composite microballoon pore-forming agent, the effects of the present invention cannot be achieved. The method according to the present invention offers higher material removal efficiency, higher uniformity within the wafer of the workpiece, a lower abrasive grain consumption rate per unit time, and contributes to reducing environmental pollution caused by processing wastewater, compared to similar processing methods for freeing abrasive grains (Comparative Examples 7-8).

[0106] As can be seen from the comparison between Example 7 and Example 8, lowering the proportion of the first abrasive material and increasing the proportion of the organic composite microballoon porosizing agent reduced the average material removal efficiency of the workpiece, but it contributed to improving the surface roughness of the workpiece.

[0107] As can be seen from the above, the combined grinding and polishing tool prepared by the method of the present invention can achieve a better overall effect in terms of both material removal rate and surface quality, significantly improving the processing uniformity of silicon carbide workpieces and reducing environmental pollution caused by processing wastewater.

[0108] Although the present invention has been described using specific examples, the above examples are merely for illustrating the technical concepts of the present invention and do not limit them. As those skilled in the art will see, it is possible to modify the technical concepts described in the above examples, or to substitute some or all of their technical features, without departing from the spirit and scope of the present invention, such modifications or substitutions will not cause the technical concepts in question to deviate from the scope of the technical concepts in each example of the present invention. For this reason, the claims attached hereto include all such substitutions and modifications that fall within the scope of the present invention.

Claims

1. The material comprises a substrate layer and an abrasive layer, the abrasive layer having a first abrasive and an organic composite microballoon pore-forming agent fixed to it, the organic composite microballoon pore-forming agent being a spherical or substantially spherical composite containing a second abrasive and a water-soluble binder, and the hardness of the second abrasive is less than or equal to the hardness of the first abrasive. A composite grinding and polishing tool that combines grinding and polishing, characterized by the following features.

2. By mass fraction, the abrasive layer contains: resin bond: 30% to 60%, the first abrasive material: 3% to 20%, the organic composite microballoon pore-forming agent: 3% to 35%, filler: 3% to 10%, and auxiliary agent: 0.2% to 15%. A composite grinding and polishing tool that combines grinding and polishing as described in feature 1.

3. (1) The particle size of the organic composite microballoon pore-forming agent is 20 to 90 μm, (2) In the organic composite microballoon pore-forming agent, the mass fraction of the water-soluble binder is 2.5% to 10%, (3) The method for preparing the organic composite microballoon pore-forming agent includes one of the following: centrifugal spray granulation, torsional granulation, or reverse-phase microemulsion polymerization. Features (1) to (3) include at least one of them A composite grinding and polishing tool that combines grinding and polishing as described in feature 1.

4. The water-soluble binder contains at least one of the following: cyclodextrin, dextrin, starch, methylolcellulose, methylcellulose, polyacrylic acid, polyacrylamide, and polyvinyl alcohol. A composite grinding and polishing tool that combines grinding and polishing as described in feature 1.

5. (1) The second abrasive material contains at least one of aluminum oxide, silicon dioxide, and cerium oxide, (2) The Mohs hardness of the second abrasive material is 6 to 9, (3) The particle size of the second abrasive material is 100 to 500 nm, Features (1) to (3) include at least one of them A composite grinding and polishing tool that combines grinding and polishing as described in feature 1.

6. (1) The first abrasive material contains at least one of diamond, silicon carbide, cubic boron nitride, zirconium oxide, and corundum. (2) The Mohs hardness of the first abrasive material is 7 to 10, (3) The particle size of the first abrasive material is 20 to 500 nm, Features (1) to (3) include at least one of them A composite grinding and polishing tool that combines grinding and polishing as described in feature 1.

7. The median diameter of the second abrasive material is greater than or equal to the median diameter of the first abrasive material. A composite grinding and polishing tool that combines grinding and polishing as described in feature 1.

8. (1) The resin bond contains at least one of unsaturated polyester, epoxy resin, and polyurethane, (2) The filler contains at least one of graphite, carbon black, short carbon fibers, carbon nanotubes, calcium carbonate, and calcium silicate. (3) The auxiliary agent includes at least one of the initiator, curing agent, and dispersant, Features (1) to (3) include at least one of them A composite grinding and polishing tool that combines grinding and polishing as described in feature 2.

9. A method for preparing a composite grinding and polishing tool that combines grinding and polishing according to any one of claims 1 to 8, Step S1 involves mixing the raw materials for the abrasive layer, degassing them to obtain a mixed material, and then placing the mixed material into a molding die. Step S2 includes: attaching a base layer to a non-grinding / polishing surface of the mixed material, and after hardening, obtaining a composite grinding / polishing tool that performs both grinding and polishing; or first hardening the mixed material to obtain an abrasive layer, and then attaching the base layer to a non-grinding / polishing surface of the abrasive layer to obtain a composite grinding / polishing tool that performs both grinding and polishing. A method for preparing a composite grinding and polishing tool that combines grinding and polishing, characterized by the above.

10. Grinding and polishing are performed on a workpiece using a combined grinding and polishing tool described in any one of claims 1 to 8. A method for grinding and polishing a workpiece, characterized by the following features.

Images