A polishing and grinding integrated composite grinding tool, a preparation method and application thereof

Abstract

The present application relates to the technical field of grinding and polishing processing, in particular to a grinding and polishing integrated composite grinding tool and a preparation method and application thereof. The grinding and polishing integrated composite grinding tool comprises a base layer and an abrasive layer, and the abrasive layer is consolidated with first abrasives and organic composite microsphere pore-forming agents. The organic composite microsphere pore-forming agents are spherical or near-spherical composites containing second abrasives and water-soluble adhesives, and the hardness of the second abrasives is less than or equal to the hardness of the first abrasives. The preparation method comprises the following steps: mixing the abrasive layer raw materials and placing them in a forming mold; attaching the base layer, and obtaining the grinding and polishing integrated composite grinding tool through solidification, or obtaining the abrasive layer through solidification and demolding, and then attaching the base layer to obtain the grinding and polishing integrated composite grinding tool. The grinding and polishing integrated composite grinding tool provided by the present application can simultaneously realize integrated processing of grinding and polishing, has few scratches, good surface quality, high material removal rate, and can balance high processing efficiency and good workpiece surface quality.

Description

Technical Field

[0001] This invention relates to the field of grinding and polishing technology, and more specifically, to an integrated grinding and polishing composite abrasive, its preparation method, and its application. Background Technology

[0002] Sapphire, ceramics, glass, silicon wafers, and other hard and brittle materials play a vital role in many fields such as electronics, military, and aerospace due to their unique high strength, high hardness, corrosion resistance, high temperature resistance, and wear resistance. However, the development of cutting-edge technologies in aerospace, electronics, and other fields has placed higher demands on the processing efficiency and surface quality of difficult-to-machine materials such as silicon carbide, sapphire, ceramics, and specialty glasses.

[0003] At present, the polishing of the above materials generally adopts the free abrasive processing technology. By using abrasive polishing fluid and elastic polishing pad together, good workpiece surface quality can be obtained. However, the polishing process has the following problems: (1) The abrasive tool does not restrict the movement of the abrasive grains. The randomness of the distribution and movement of the abrasive grains will reduce the processing efficiency and reduce the uniformity within the wafer. (2) The abrasive stays on the surface of the abrasive tool for a short time, resulting in low abrasive utilization and large waste liquid pollution.

[0004] Currently, some existing technologies employ bonded abrasive polishing to address the aforementioned problems. By fixing the abrasive within the grinding wheel, the movement of the abrasive grains is fully constrained, improving abrasive distribution uniformity, material removal efficiency, and abrasive utilization. However, the surface damage and scratches caused by abrasive ploughing under the two-body wear mechanism mean that this technology cannot completely replace traditional free abrasive polishing. Bonded abrasive polishing still requires a follow-up free abrasive fine polishing process. Against this backdrop, developing a highly efficient precision machining technology that balances processing efficiency and polishing quality is of great significance.

[0005] In view of this, the present invention is hereby proposed. Summary of the Invention

[0006] The primary objective of this invention is to provide an integrated grinding and polishing composite abrasive to address the technical problems of existing technologies, such as low processing efficiency, poor uniformity within the abrasive particles, low abrasive utilization, and significant waste liquid pollution in free abrasive processing technology, as well as severe surface scratches on workpieces in bonded abrasive polishing technology, which still requires fine polishing with free abrasive particles after bonded abrasive polishing. The integrated grinding and polishing composite abrasive provided by this invention can simultaneously achieve integrated grinding and polishing processing, resulting in fewer scratches, better surface quality, and higher material removal rate, thus balancing high processing efficiency and good workpiece surface quality.

[0007] The second objective of this invention is to provide a method for preparing the integrated grinding and polishing composite abrasive as described above.

[0008] The third objective of this invention is to provide a method for grinding and polishing a workpiece, wherein the workpiece is ground and polished using an integrated grinding and polishing composite abrasive as described above.

[0009] In order to achieve the above-mentioned objectives of the present invention, the following technical solution is adopted:

[0010] A composite abrasive tool integrating grinding and polishing includes a matrix layer and an abrasive layer. The abrasive layer contains a first abrasive and an organic composite microsphere pore-forming agent. The organic composite microsphere pore-forming agent is a spherical or near-spherical composite containing a second abrasive and a water-soluble binder. The hardness of the second abrasive is less than or equal to the hardness of the first abrasive.

[0011] Preferably, by mass percentage, the abrasive layer comprises 30%-60% resin binder, 3%-20% of the first abrasive, 3%-35% of the organic composite microsphere pore-forming agent, 3%-10% filler, and 0.2%-15% additives.

[0012] Preferably, the particle size of the organic composite microsphere pore-forming agent is 20-90 μm.

[0013] Preferably, the water-soluble binder comprises 2.5%-10% by mass in the organic composite microsphere pore-forming agent.

[0014] Preferably, the organic composite microsphere pore-forming agent is prepared by one of centrifugal spray granulation, granulation, or reverse microemulsion polymerization.

[0015] Preferably, the water-soluble adhesive includes at least one of cyclodextrin, dextrin, starch, hydroxymethyl cellulose, methyl cellulose, polyacrylic acid, polyacrylamide, and polyvinyl alcohol.

[0016] Preferably, the second abrasive comprises at least one of alumina, silicon dioxide, and cerium oxide.

[0017] Preferably, the Mohs hardness of the second abrasive is 6-9.

[0018] Preferably, the particle size of the second abrasive is 100-500 nm.

[0019] Preferably, the first abrasive includes at least one of diamond, silicon carbide, cubic boron nitride, zirconium oxide, and corundum.

[0020] Preferably, the Mohs hardness of the first abrasive is 7-10.

[0021] Preferably, the particle size of the first abrasive is 20-500 nm.

[0022] Preferably, the median particle size of the second abrasive is not less than the median particle size of the first abrasive.

[0023] Preferably, the resin binder includes at least one of unsaturated polyester, epoxy resin, and polyurethane.

[0024] Preferably, the filler comprises one or more combinations of graphite, carbon black, carbon fiber short fibers, carbon nanotubes, calcium carbonate, and calcium silicate.

[0025] Preferably, the additive includes at least one of an initiator, a curing agent, and a dispersant.

[0026] A method for preparing the integrated grinding and polishing composite abrasive as described above includes the following steps:

[0027] S1. After mixing the raw materials of the abrasive layer, degas the mixture to obtain a mixture, and place the mixture in a molding die;

[0028] S2. A substrate layer is applied to the surface of the non-grinding and polishing surface of the mixture and cured to obtain the integrated grinding and polishing composite abrasive; or, the mixture is first cured to obtain an abrasive layer, and then the substrate layer is applied to the surface of the non-grinding and polishing surface of the abrasive layer to obtain the integrated grinding and polishing composite abrasive.

[0029] A method for grinding and polishing a workpiece, wherein the workpiece is ground and polished using an integrated grinding and polishing composite abrasive as described above.

[0030] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0031] (1) The integrated grinding and polishing composite abrasive provided by the present invention has a first abrasive and an organic composite microsphere pore-forming agent solidified in the abrasive layer. During the processing of the workpiece, the first abrasive, as the solidified abrasive, plays the role of grinding the workpiece and improving the material removal rate. The organic composite microsphere pore-forming agent on the surface of the abrasive encounters the water-based grinding fluid on the surface of the abrasive during the processing of the workpiece, and the water-soluble binder undergoes physical dissolution, which can form an open pore structure on the surface of the abrasive. The pore structure contains a free distribution of the second abrasive. On the one hand, the organic composite microsphere pore-forming agent acts as a pore-forming agent, increasing the chip space inside the abrasive and reducing the hardness of the abrasive matrix, thereby reducing scratches on the workpiece surface and enhancing the self-sharpening property of the abrasive. On the other hand, it introduces free abrasive particles into the composite abrasive, which plays the role of polishing the workpiece and improving the surface quality of the material. It can realize the integrated processing of grinding and polishing at the same time, with fewer scratches, better surface quality, and higher material removal rate, taking into account both high processing efficiency and good workpiece surface quality.

[0032] (2) The workpiece surface is ground and polished by the integrated grinding and polishing composite abrasive provided by the present invention. Compared with the traditional free abrasive polishing technology, the abrasive consumption is small and the waste liquid pollution can be reduced. Compared with the traditional bonded abrasive processing technology, the workpiece has fewer scratches and better surface quality after processing, and no further fine polishing is required. Attached Figure Description

[0033] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0034] Figure 1 A schematic diagram illustrating the preparation process of the organic composite microsphere pore-forming agent provided in an embodiment of the present invention;

[0035] Figure 2 This is a schematic diagram of the forming process of the integrated grinding and polishing composite abrasive provided in an embodiment of the present invention;

[0036] Figure 3 This is a schematic diagram of the working surface of the integrated grinding and polishing composite abrasive provided in an embodiment of the present invention;

[0037] Figure 4 This is a grinding mechanism diagram of the integrated grinding and polishing composite abrasive provided in an embodiment of the present invention;

[0038] Figure 5 The surface morphology of the integrated grinding and polishing composite abrasive provided in the embodiments of the present invention is shown in the following images (wherein, the leftmost image is the overall surface view of the composite abrasive, the middle image is the pores formed on the surface of the composite abrasive by the organic composite microsphere pore-forming agent, and the rightmost image is the free state of the second abrasive inside the pores).

[0039] Figure 6 This is a schematic diagram illustrating the working process of the grinding and polishing apparatus provided in an embodiment of the present invention. Detailed Implementation

[0040] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings and specific embodiments. However, those skilled in the art will understand that the embodiments described below are some embodiments of the present invention, but not all embodiments, and are only used to illustrate the present invention, and should not be regarded as limiting the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall be followed. Where the manufacturers of reagents or instruments are not specified, they are all conventional products that can be purchased commercially.

[0041] The first aspect of the present invention provides an integrated grinding and polishing composite abrasive, comprising a matrix layer and an abrasive layer, wherein a first abrasive and an organic composite microsphere pore-forming agent are solidified in the abrasive layer, the organic composite microsphere pore-forming agent being a spherical or near-spherical composite containing a second abrasive and a water-soluble binder, and the hardness of the second abrasive being less than or equal to the hardness of the first abrasive.

[0042] To address the problems of low processing efficiency, poor uniformity within the abrasive grains, low abrasive utilization, and significant waste liquid pollution in existing technologies, as well as severe surface scratches on workpieces caused by bonded abrasive grain processing, this invention provides an integrated grinding and polishing composite abrasive. It combines the advantages of both bonded and free abrasive grain processing, enabling simultaneous grinding and polishing. This results in fewer scratches, better surface quality, and higher material removal rate, achieving both high processing efficiency and excellent workpiece surface quality.

[0043] This invention incorporates a first abrasive and an organic composite microsphere pore-forming agent, which are solidified within an abrasive layer. Figure 3 and Figure 5 As shown, the first abrasive, acting as a bonded abrasive, grinds the workpiece and improves the material removal rate. The organic composite microsphere pore-forming agent on the surface of the composite abrasive comes into contact with the water-based grinding fluid on the abrasive surface during workpiece processing. The water-soluble binder dissolves, forming an open pore structure on the abrasive surface. This pore structure contains freely distributed second abrasive particles. The organic composite microsphere pore-forming agent, on one hand, acts as a pore-forming agent, increasing the chip space inside the abrasive and reducing the hardness of the abrasive matrix, thereby reducing scratches on the workpiece surface and enhancing the self-sharpening properties of the abrasive. On the other hand, it releases free abrasive components in situ during the operation of the composite abrasive, polishing the workpiece and improving the surface quality of the material; thus achieving integrated grinding and polishing processing.

[0044] By controlling the hardness of the first abrasive to be no less than that of the second abrasive, selecting the first abrasive with relatively higher hardness as the bonded abrasive for grinding, and the second abrasive with relatively lower hardness as the free abrasive for polishing, both high grinding efficiency and surface quality of the workpiece can be guaranteed.

[0045] In some specific embodiments of the present invention, the first abrasive and the organic composite microsphere pore-forming agent are uniformly distributed in the abrasive layer.

[0046] In some specific embodiments of the present invention, the abrasive layer comprises, by weight percentage, 30%-60% resin binder, 3%-20% first abrasive, 3%-35% organic composite microsphere pore-forming agent, 3%-10% filler, and 0.2%-15% additives.

[0047] Among them, the resin binder plays the role of fixing the first abrasive, the organic composite microsphere pore-forming agent, the filler and other components. It is the key part of the composite abrasive that bears and transmits the load and maintains the polishing liquid environment. The filler plays the role of enhancing the strength of the grinding layer, and the additives mainly play the role of initiating the reaction or improving the cross-linking degree of the resin system or promoting the dispersion of components.

[0048] In some embodiments, typically but not limitingly, for example, the mass percentage of the resin binder in the abrasive layer can be any single value or a range of any two values ​​from 30%, 35%, 39%, 45%, 52%, 55%, and 60%; the mass percentage of the first abrasive can be any single value or a range of any two values ​​from 3%, 5%, 8%, 11%, 15%, 18%, and 20%; and the mass percentage of the organic composite microsphere pore-forming agent can be 3%, 5%, 10%, 5%, 60%, 3 ... The mass percentage of filler can be any one value or a range of any two values ​​from % to 35%; the mass percentage of additive can be any one value or a range of any two values ​​from 3% to 10%; the mass percentage of auxiliary agent can be any one value or a range of any two values ​​from 0.2% to 15%; the mass percentage of additive can be any one value or a range of any two values ​​from 0.2% to 15%; the mass percentage of auxiliary agent can be any one value or a range of any two values ​​from 0.2% to 15%; the mass percentage of additive can be any one value or a range of any two values ​​from 0.2% to 15%; the mass percentage of additive can be any one value or a range of any two values ​​from 0.2% to 15%; the mass percentage of additive agent ...

[0049] In some specific embodiments of the present invention, the particle size of the organic composite microsphere pore-forming agent is 20-90 μm. For example, it can be any single value or a range of any two values ​​from 20 μm, 25 μm, 32 μm, 38 μm, 45 μm, 50 μm, 60 μm, 70 μm, 80 μm, and 90 μm. If the particle size of the organic composite microsphere pore-forming agent is too small, the sieving equipment cannot accurately sieve and control the particle size of the pore-forming agent during preparation. Furthermore, during the processing of the workpiece, the diameter of the open pores formed on the surface of the abrasive is too small, resulting in poor polishing of the workpiece, improvement of material surface quality, and enhancement of the self-sharpening property of the abrasive. If the particle size of the organic microsphere pore-forming agent is too large, the structural stability of the abrasive polishing surface is easily destroyed, and the stability of the polishing effect cannot be guaranteed. Therefore, it is necessary to reasonably control the particle size range of the organic composite microsphere pore-forming agent.

[0050] In some specific embodiments of the present invention, the water-soluble binder in the organic composite microsphere pore-forming agent has a mass percentage of 2.5%-10%, for example, it can be any one value or a range of any two values ​​from 2.5%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%.

[0051] If the content of water-soluble binder in the organic composite microsphere pore-forming agent is too low, the second abrasive will easily become loose and difficult to bond and aggregate into spheres; if the content of water-soluble binder is too high, the content of the second abrasive in the organic composite microsphere pore-forming agent will be too low, which will lead to the content of the second abrasive in the open pores of the composite abrasive and the poor polishing effect of the free abrasive. Therefore, it is necessary to reasonably control the composition and content of the organic composite microsphere pore-forming agent.

[0052] like Figure 1 As shown, in some specific embodiments of the present invention, the preparation method of the organic composite microsphere pore-forming agent is centrifugal spray granulation, which includes the following steps:

[0053] The second abrasive, water-soluble binder and water are mixed and dispersed to obtain an aqueous dispersion with a mass fraction of 10%-35% of the second abrasive. The aqueous dispersion is then granulated and sieved using centrifugal spray granulation technology to obtain the final product.

[0054] In some specific embodiments of the present invention, the mixing and dispersion methods used in preparing the aqueous dispersion include shear dispersion and / or ultrasonic dispersion.

[0055] In some specific embodiments of the present invention, granulation is carried out in a centrifugal spray drying device, the inlet rate of the aqueous dispersion is 10-40 ml / min, the inlet air temperature is 160-250℃, and the centrifugation frequency is 200-400 Hz.

[0056] In some embodiments, typically but not limitingly, for example, the mass fraction of the second abrasive in the aqueous dispersion can be any one value or a range of any two values ​​from 10%, 15%, 20%, 25%, 30%, and 35%; the inlet flow rate of the aqueous dispersion can be any one value or a range of any two values ​​from 10 ml / min, 20 ml / min, 30 ml / min, and 40 ml / min; the inlet air temperature can be any one value or a range of any two values ​​from 160°C, 180°C, 200°C, 210°C, 230°C, and 250°C; and the centrifugation frequency can be any one value or a range of any two values ​​from 200 Hz, 220 Hz, 250 Hz, 280 Hz, 300 Hz, 320 Hz, 350 Hz, 380 Hz, and 400 Hz.

[0057] Excessive concentration (or low concentration) of aqueous dispersion, excessive or insufficient inlet flow rate, and excessive or insufficient centrifugation frequency can all cause the organic composite microsphere pore-forming agent to have an excessively large (or small) particle size. If the inlet air temperature is too low, the organic composite microsphere pore-forming agent cannot be completely dried and is prone to particle adhesion and clumping. If the inlet air temperature is too high, the water-soluble binder will decompose due to heat and the moisture will dry too quickly, causing the microspheres to break and the shape of the pore-forming agent to be destroyed.

[0058] In other embodiments of the present invention, the organic composite microsphere pore-forming agent can also be prepared by other methods such as granulation or reverse microemulsion polymerization.

[0059] In some specific embodiments of the present invention, the water-soluble binder includes at least one of cyclodextrin, dextrin, starch, hydroxymethyl cellulose, methyl cellulose, polyacrylic acid, polyacrylamide, and polyvinyl alcohol; the water-soluble binder plays a role in bonding the second abrasive during the preparation of the organic composite microsphere pore-forming agent and the composite abrasive.

[0060] In some specific embodiments of the present invention, the second abrasive includes at least one of aluminum oxide, silicon dioxide, and cerium oxide.

[0061] In some specific embodiments of the present invention, the Mohs hardness of the second abrasive is 6-9, for example, it can be 6, 7, 8 or 9.

[0062] In some specific embodiments of the present invention, the particle size of the second abrasive is 100-500nm, for example, it can be any one value or a range of any two values ​​among 100nm, 200nm, 300nm, 400nm, and 500nm.

[0063] In some specific embodiments of the present invention, the first abrasive includes at least one of diamond, silicon carbide, cubic boron nitride, zirconium oxide, and corundum, wherein the diamond can be one or a combination of single crystal, polycrystalline, and quasi-polycrystalline.

[0064] In some specific embodiments of the present invention, the Mohs hardness of the first abrasive is 7-10, for example, it can be 7, 8, 9 or 10.

[0065] In some specific embodiments of the present invention, the particle size of the first abrasive is 20-500nm. For example, it can be any one value or a range of any two values ​​among 20nm, 100nm, 200nm, 300nm, 400nm, and 500nm.

[0066] In some specific embodiments of the present invention, the median particle size of the second abrasive is not less than the median particle size of the first abrasive, which is beneficial to improving the polishing effect.

[0067] In some specific embodiments of the present invention, the resin binder includes at least one of unsaturated polyester, epoxy resin, and polyurethane, such as epoxy acrylate, polyethylene glycol acrylate, polyurethane acrylate, bisphenol A type epoxy resin, bisphenol F type epoxy resin, polyphenol type glycidyl ether epoxy resin, aliphatic glycidyl ether epoxy resin, glycidyl ester type epoxy resin, polyester type polyurethane, polyether type polyurethane, etc.

[0068] In some specific embodiments of the present invention, the filler includes one or more combinations of graphite, carbon black, carbon fiber short fibers, carbon nanotubes, calcium carbonate, and calcium silicate. The filler mainly serves to enhance the strength of the grinding layer.

[0069] In some specific embodiments of the present invention, the additives include at least one of an initiator, a curing agent, and a dispersant; for example, the initiator may be azobisisobutyronitrile, benzoyl peroxide, tetraphenylethylene glycol, tetraphenylbutadiene nitrile, initiator 184, initiator 1173, initiator TPO, or initiator 819, etc., which play a role in initiating the polymerization reaction of the unsaturated polyester system; the curing agent may be aliphatic amines, aromatic amines, acid anhydrides, isocyanate curing agents, polyhydroxy curing agents, etc., which play a role in improving the crosslinking degree of the resin system and promoting the hardening and shaping of the abrasive; the dispersant may be silane coupling agents KH550, KH560, KH570, etc., which play a role in improving the interfacial bonding strength of the abrasive, filler, and binder and promoting the uniform dispersion of components.

[0070] In some specific embodiments of the present invention, the matrix layer is a polymer sheet. For example, the matrix layer polymer can be carbon fiber, PET, PC, PMMA, PS, PI, epoxy resin, phenolic resin, polyurethane, rubber elastomer or silicone elastomer.

[0071] like Figure 2 As shown, a second aspect of the present invention provides a method for preparing an integrated grinding and polishing composite abrasive as described in any of the foregoing embodiments, comprising the following steps:

[0072] S1. After mixing the raw materials of the abrasive layer, degas the mixture to obtain a mixture, and place the mixture in a molding die with a specific morphology;

[0073] S2. Apply a substrate layer to the non-grinding and polishing surface of the mixture and cure it to obtain an integrated grinding and polishing composite abrasive; or, first cure and demold the mixture to obtain an abrasive layer, and then apply a substrate layer to the non-grinding and polishing surface of the abrasive layer to obtain an integrated grinding and polishing composite abrasive.

[0074] The method of this invention has a simple preparation process, and the prepared grinding and polishing integrated abrasive can simultaneously achieve integrated grinding and polishing processing, with fewer scratches, good surface quality, and high material removal rate. It takes into account both high processing efficiency and good workpiece surface quality, and combines the advantages of free abrasive processing and bonded abrasive processing.

[0075] In some specific embodiments of the present invention, the curing method is photocuring or thermal curing.

[0076] In some specific embodiments of the present invention, the intensity of the ultraviolet light used for photocuring is 500-1500 mW / cm². 2 For example, it can be 500mW / cm2 750mW / cm 2 1000mW / cm 2 1250mW / cm 2 1500mW / cm 2 The value can be any one point or any two points within the range; the irradiation time is 20-120s, for example, it can be any one point or any two points within the range of 20s, 40s, 60s, 80s, 100s, and 120s.

[0077] In some specific embodiments of the present invention, the substrate layers are bonded together by organic adhesives or double-sided adhesives. For a mold containing multiple different substrate layers, the different substrate layers can also be bonded together by organic adhesives or double-sided adhesives.

[0078] In some specific embodiments of the present invention, the organic adhesive may be one or more of hot-melt or reactive adhesives, such as epoxy resin adhesives, polyurethane resin adhesives, polyimide adhesives, silicone adhesives, acrylate adhesives, acrylic adhesives, etc.

[0079] In some specific embodiments of the present invention, the double-sided adhesive can be a resin-based hot melt adhesive and / or a pressure-sensitive adhesive.

[0080] A third aspect of the present invention provides a method for grinding and polishing a workpiece, wherein the workpiece is ground and polished using an integrated grinding and polishing composite abrasive as described in any of the foregoing embodiments. The composite abrasive is used in conjunction with a water-based grinding fluid during the grinding and polishing process, and an open cavity containing a second abrasive can be formed on the surface. As the composite abrasive wears down, the second abrasive is released layer by layer from top to bottom.

[0081] In some specific embodiments of the present invention, the material of the processed workpiece can be a difficult-to-process brittle and hard material such as silicon carbide, sapphire, ceramics or special glass.

[0082] In some specific embodiments of the present invention, the water-based grinding fluid is composed of water, an oxidant, a pH adjuster, a catalyst, and other components. Water is the main component of the grinding fluid, providing a liquid environment, dissolving the pore-forming agent, and carrying away processing heat during the processing; its mass fraction is 80%–98%. The oxidant is potassium permanganate, which forms a relatively soft oxide reaction layer on the surface of silicon carbide through an oxidation reaction, reducing the hardness of the processed workpiece; its mass fraction is 1%–20%. The pH adjuster is one or more of hydrochloric acid, sulfuric acid, nitric acid, acetic acid, sodium hydroxide, potassium hydroxide, ammonia, trimethylammonium hydroxide, etc., which adjusts the pH of the grinding fluid and regulates the oxidizing power of potassium permanganate; the system pH is typically between 4–6 or 9–11. The catalyst is manganese dioxide, which can be added during the preparation of the grinding fluid or provided by the oxidation and decomposition products of potassium permanganate, catalyzing and regulating the oxidation reaction rate; typically, the added manganese dioxide mass fraction is 0–2%.

[0083] like Figure 4 As shown, the working principle of grinding and polishing workpieces using the above-mentioned integrated grinding and polishing composite abrasive is as follows: During the grinding and polishing process, the oxidant in the water-based grinding fluid reacts chemically with the workpiece surface under the action of a catalyst, generating a softening film layer with a hardness lower than that of the workpiece; simultaneously, the water-soluble binder in the organic microsphere pore-forming agent on the abrasive surface comes into contact with and dissolves in water, forming spherical or near-spherical open pores on the surface of the composite abrasive, with free second abrasive particles inside the pores; the first and second abrasive particles in the abrasive layer mechanically remove the softening film layer on the workpiece surface. Among them, the first abrasive particle has a higher hardness than the second abrasive particle and mainly plays the role of material removal, while the second abrasive particle mainly plays the role of polishing.

[0084] The following detailed description of some embodiments of the present invention is provided in conjunction with specific examples. Unless otherwise specified, all raw materials used in the embodiments are commercially available.

[0085] In Examples 1-8, the first abrasive d 50 The particle size of all particles is 200 nm; the particle size of the organic composite microsphere pore-forming agent is 32-38 μm, both obtained by centrifugal spray granulation. The second abrasive d 50 The particle size is 250 nm. The median particle size of the filler used is 0.5 μm; the unsaturated polyester used is a mixture of prepolymer PEG400DA and crosslinking agent, the epoxy resin is urethane-modified epoxy resin UME308, and the polyurethane is a mixture of polyester-type polyurethane prepolymer and diethylenetriamine; wherein, the dispersant used in the unsaturated polyester system is KH570, the dispersant used in the epoxy resin system is KH560, and the dispersant used in the polyurethane system is KH550. The abrasive layer formulation composition in Examples 1-8 is shown in Table 1.

[0086] Table 1

[0087]

[0088] Example 1

[0089] The formulation of the abrasive layer in this embodiment is shown in Table 1. The substrate layer uses a 0.15mm thick PET sheet. The preparation method of the integrated grinding and polishing composite abrasive is as follows:

[0090] S1. Mix the abrasive layer raw materials weighed according to the proportions in Table 1 evenly, degas and cast them into a molding mold with a specific morphology;

[0091] S2. Place the molding mold in a forced-air drying oven and use a thermosetting method to form and cure it. The curing process is 80℃ / 2h + 100℃ / 2h + 120℃ / 1h. After curing and demolding, an abrasive layer is obtained. A PET substrate layer is then attached to the non-abrasive surface of the abrasive layer with double-sided adhesive to obtain an integrated grinding and polishing composite abrasive.

[0092] Example 2

[0093] The formulation of the abrasive layer in this embodiment is shown in Table 1. The substrate layer uses 0.15mm thick PET sheet. The preparation method of the integrated grinding and polishing composite abrasive is the same as in Example 1.

[0094] Example 3

[0095] The formulation of the abrasive layer in this embodiment is shown in Table 1. The substrate layer uses a 0.2mm thick polyurethane sheet. The preparation method of the integrated grinding and polishing composite abrasive is as follows:

[0096] S1. Mix the abrasive layer raw materials weighed according to the proportions in Table 1 evenly, degas and cast them into a molding mold with a specific morphology;

[0097] S2. Place the molding mold in a forced-air drying oven and use a thermosetting method to form and cure it. The curing process is 80℃ / 2h + 100℃ / 2h + 140℃ / 2h. After curing and demolding, an abrasive layer is obtained. A polyurethane matrix layer is then attached to the non-abrasive surface of the abrasive layer with double-sided adhesive to obtain an integrated grinding and polishing composite abrasive.

[0098] Example 4

[0099] The formulation of the abrasive layer in this embodiment is shown in Table 1. The substrate layer uses a 0.2mm thick polyurethane sheet. The preparation method of the integrated grinding and polishing composite abrasive is the same as in Example 3.

[0100] Example 5

[0101] The formulation of the abrasive layer in this embodiment is shown in Table 1. The substrate layer uses 0.15mm thick PC sheet. The preparation method of the integrated grinding and polishing composite abrasive is as follows:

[0102] S1. Mix the abrasive layer raw materials weighed according to the proportions in Table 1 evenly, degas and cast them into a molding mold with a specific morphology;

[0103] S2. The PC substrate sheet is applied to the non-grinding and polishing surface of the molding material, and the bubbles are removed again. The molding mold is placed in a forced-air drying oven and cured and demolded through a process to obtain an integrated grinding and polishing composite abrasive. The curing process is 60℃ / 30min.

[0104] Example 6

[0105] The formulation of the abrasive layer in this embodiment is shown in Table 1. The substrate layer uses 0.15mm thick PC sheet. The preparation method of the integrated grinding and polishing composite abrasive is the same as in Example 5.

[0106] Example 7

[0107] The formulation of the abrasive layer in this embodiment is shown in Table 1. The substrate layer uses a 0.15mm thick PET sheet. The preparation method of the integrated grinding and polishing composite abrasive is as follows:

[0108] S1. Mix the abrasive layer raw materials weighed according to the proportions in Table 1 evenly, degas and cast them into a molding mold with a specific morphology;

[0109] S2. The PET matrix sheet is laminated onto the non-grinding / polishing surface of the molding material, degassed again, cured by a light-curing process, and then demolded to obtain an integrated grinding and polishing composite abrasive; wherein, the light-curing process uses a light intensity of 1000mW / cm². 2 Expose to UV light for 80 seconds.

[0110] Example 8

[0111] The formulation of the abrasive layer in this embodiment is shown in Table 1. The substrate layer uses 0.15mm thick PET sheet. The preparation method of the integrated grinding and polishing composite abrasive is the same as in Example 7.

[0112] Comparative Example 1

[0113] Comparative Example 1 is similar to Example 1, except that no organic composite microsphere pore-forming agent was added to the abrasive layer of Comparative Example 1, while the proportions of other components remained unchanged. The substrate layer and abrasive preparation methods were the same as in Example 1.

[0114] Comparative Example 2

[0115] Comparative Example 2 is similar to Example 3, except that no organic composite microsphere pore-forming agent was added to the abrasive layer of Comparative Example 2, while the proportions of other components remained unchanged. The substrate layer and abrasive preparation methods were the same as in Example 3.

[0116] Comparative Example 3

[0117] Comparative Example 3 is similar to Example 5, except that no organic composite microsphere pore-forming agent was added to the abrasive layer of Comparative Example 3, while the proportions of other components remained unchanged. The substrate layer and abrasive preparation methods were the same as in Example 5.

[0118] Comparative Example 4

[0119] Comparative Example 4 is similar to Example 1, except that alumina is replaced with an equal amount of dextrin (dextrin content is 25 wt%, alumina content is 0), and dextrin microspheres without the second abrasive are used instead of the organic composite microsphere pore-forming agent in Example 1. All other conditions are the same as in Example 1.

[0120] Comparative Example 5

[0121] Comparative Example 5 is similar to Example 1, except that dextrin is replaced with an equal amount of alumina (dextrin content is 0, alumina content is 25 wt%), and a second abrasive is used instead of the organic composite microsphere pore-forming agent in Example 1. All other conditions are the same as in Example 1.

[0122] Comparative Example 6

[0123] Comparative Example 6 is similar to Example 1, except that dextrin (water-soluble binder) and alumina (second abrasive) were not granulated, and the content of each component was the same as in Example 1. All raw materials were directly mixed to prepare the composite abrasive, and the remaining process conditions were the same as in Example 1.

[0124] Test case

[0125] (1) Density, dry hardness and abrasive surface pore size testing

[0126] The density and dry hardness of the abrasive layer of the composite abrasive prepared in each embodiment and each comparative example were tested, and the pore size of the pores generated on the surface of the composite abrasive after the water-soluble binder in the organic composite microsphere pore-forming agent was dissolved was tested.

[0127] Density was measured using a density meter, and the liquid medium used in the test was kerosene.

[0128] Dry hardness: The water-soluble binder in the organic microsphere pore-forming agent on the surface of the abrasive layer was not dissolved. The hardness data was measured using a Shore C hardness tester.

[0129] The pore size was determined by dissolving the water-soluble binder in the organic composite microsphere pore-forming agent on the surface of the abrasive layer in water and then drying it, and leaving it at room temperature for 24 hours. The pore size data was obtained by SEM, and the average value of 20 pore size data in the same area was taken.

[0130] The test results are shown in Table 2.

[0131] Table 2

[0132] Example 1 1.59±0.10 82±4 34±5 Example 2 1.70±0.10 79±4 33±4 Example 3 1.43±0.11 74±3 34±4 Example 4 1.39±0.10 78±4 33±5 Example 5 1.62±0.12 72±5 33±4 Example 6 1.66±0.11 69±4 34±5 Example 7 1.60±0.13 72±5 34±3 Example 8 1.59±0.10 68±3 33±4 Comparative Example 1 1.40±0.09 83±3 / Comparative Example 2 1.30±0.10 76±4 / Comparative Example 3 1.31±0.08 74±3 / Comparative Example 4 1.17±0.09 79±5 33±6 Comparative Example 5 1.64±0.12 85±6 / Comparative Example 6 1.62±0.16 81±4 /

[0133] As shown in Table 2, the density of the abrasive layer in the dry, unpore-forming state is related to the composition ratio in the formula. When the proportions of other components do not change significantly, the density of the abrasive layer of the abrasive tool with added organic microsphere pore-forming agent is mainly affected by the type and content of each component in the organic microsphere pore-forming agent. As shown in Example 1 and Comparative Example 6, when the formula composition is the same, the density of the composite abrasive tool prepared by adding organic composite microsphere pore-forming agent is not much different from that of the abrasive tool prepared by mixing all raw materials (without granulation).

[0134] A comparison of Example 1 with Comparative Example 1, Example 3 with Comparative Example 2, and Example 5 with Comparative Example 3 shows that the introduction of the organic composite microsphere pore-forming agent in the examples slightly reduces the hardness of the abrasive layer. A comparison of Example 1 with Examples 7-8 shows that reducing the proportion of the first abrasive and increasing the proportion of the organic composite microsphere pore-forming agent significantly reduces the hardness of the abrasive layer.

[0135] As can be seen from Examples 1 to 8, the pore size on the surface of the abrasive layer is similar to the diameter of the organic composite microsphere pore-forming agent, and the pore size on the surface of the abrasive layer obtained by this method is relatively uniform.

[0136] (2) Polishing performance test

[0137] During the grinding and polishing process, the abrasives of Examples 1, 3, 5, 7, 8 and Comparative Examples 1 to 6 were used in conjunction with abrasive-free grinding and polishing slurry (KMnO4 polishing slurry, pH = 5.2 to 5.8);

[0138] Comparative Example 7 is an example of using SUBA800 as a polishing pad and a silica polishing slurry with a particle size of 250 nm (pH = 10.0~10.5, abrasive solid content 2wt%) for free abrasive processing.

[0139] Comparative Example 8 uses SUBA800 as a polishing pad and a diamond polishing slurry (KMnO4 polishing slurry, pH=5.2~5.8, abrasive solid content 2wt%) with a particle size of 200nm for free abrasive processing.

[0140] The testing process is as follows Figure 6 As shown, the grinding tools in Examples 1, 3, 5, 7, 8 and Comparative Examples 1 to 8 are fixed on a turntable, and a 4-inch SiC single crystal wafer is fixed on a workpiece carrier (Si side down). The polishing slurry is supplied through a liquid supply device, and other processing parameters are shown in Table 3.

[0141] Table 3

[0142]

[0143]

[0144] The average material removal rate, surface roughness, intra-piece non-uniformity, and average abrasive consumption rate of each embodiment and comparative example were tested as indicators for evaluating the grinding and polishing effect.

[0145] The average material removal efficiency was calculated using the mass method.

[0146] Surface roughness was measured using a white light interferometer.

[0147] In-wafer non-uniformity measurement: Along two mutually perpendicular diameters on the wafer processing surface, 17 points are uniformly selected from the wafer edge, through the center, to the other edge, and the thickness H is measured. Calculation formula: Non-uniformity = (H) / (H) max -H min ) / (2×H 均值 )×100%;

[0148] The average abrasive consumption rate was calculated as follows: In Examples 1, 3, 5, 7, 8 and Comparative Examples 1 to 6, the average abrasive consumption rate = abrasive consumption amount in the preparation of the abrasive tool / abrasive tool life; in Comparative Examples 7 to 8, the average abrasive consumption rate = polishing slurry flow rate × polishing slurry density × abrasive mass fraction in the polishing slurry.

[0149] The test results are shown in Table 4.

[0150] Table 4

[0151]

[0152] As shown in Table 4, the composite abrasives prepared in the embodiments of the present invention (Examples 1, 3, and 5) have higher average material removal rates and lower workpiece surface roughness compared to abrasives with the same formulation but without organic composite microsphere pore-forming agents (Comparative Examples 1-3), thus achieving a balance between processing efficiency and surface quality. A comparison of Example 1 with Comparative Examples 4-6 shows that the processing effect of the present invention depends on the introduction of the organic composite microsphere pore-forming agent; the same processing effect cannot be achieved by simply mixing some or all of the raw materials of the organic composite microsphere pore-forming agent in the abrasive layer. In other words, even with the same formulation, if the second abrasive and water-soluble binder are directly mixed with other raw materials to prepare the abrasive without pre-granulating the second abrasive and water-soluble binder to prepare an organic composite microsphere pore-forming agent, the effect of the present invention cannot be achieved. Compared with the free processing scheme of the same type of abrasive (Comparative Examples 7-8), the method of the present invention has higher material removal efficiency, better intra-piece uniformity of the processed workpiece, and a lower abrasive consumption rate per unit time, which is beneficial to reducing the pollution of processing wastewater to the environment.

[0153] A comparison of Examples 7 and 8 shows that reducing the proportion of the first abrasive and increasing the proportion of the organic composite microsphere pore-forming agent reduces the average material removal efficiency of the workpiece but helps improve the surface roughness of the workpiece.

[0154] As can be seen from the above discussion, the integrated grinding and polishing composite abrasive prepared by the method of the present invention can achieve better overall results in terms of material removal rate and surface quality, while significantly improving the processing uniformity of silicon carbide workpieces and reducing the pollution of processing waste liquid to the environment.

[0155] Although the present invention has been illustrated and described with specific embodiments, it should be understood that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; those skilled in the art should understand that modifications can be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein, without departing from the spirit and scope of the present invention; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention; therefore, this means that all such substitutions and modifications that fall within the scope of the present invention are included in the appended claims.

Claims

1. A method for grinding and polishing a workpiece, characterized in that, The workpiece is ground and polished using an integrated grinding and polishing composite abrasive; the integrated grinding and polishing composite abrasive is used in conjunction with a water-based grinding fluid during the grinding and polishing process, the water-based grinding fluid being composed of water, oxidant, pH adjuster, and catalyst; The integrated grinding and polishing composite abrasive includes a matrix layer and an abrasive layer. The abrasive layer contains a first abrasive and an organic composite microsphere pore-forming agent. The organic composite microsphere pore-forming agent is a spherical or near-spherical composite containing a second abrasive and a water-soluble binder. The hardness of the second abrasive is less than or equal to the hardness of the first abrasive. The first abrasive has a Mohs hardness of 7-10 and a particle size of 20-500 nm. The second abrasive has a Mohs hardness of 6-9 and a particle size of 100-500 nm. The median particle size of the material is not less than the median particle size of the first abrasive. During the workpiece processing, the first abrasive, as a bonded abrasive, plays a role in grinding the workpiece and improving the material removal rate. The organic composite microsphere pore-forming agent on the surface of the surface encounters the water-based grinding fluid on the surface of the grinding wheel during the workpiece processing. The water-soluble binder undergoes physical dissolution, which can form an open pore structure on the surface of the grinding wheel. The pore structure contains the second abrasive distributed freely, which plays a role in polishing the workpiece and improving the surface quality of the material. The integrated processing of grinding and polishing is realized simultaneously. By weight percentage, the abrasive layer comprises 30%-60% resin binder, 3%-20% of the first abrasive, 3%-35% of the organic composite microsphere pore-forming agent, 3%-10% filler, and 0.2%-15% additives; In the organic composite microsphere pore-forming agent, the water-soluble binder has a mass percentage of 2.5%-10%.

2. The grinding and polishing method according to claim 1, characterized in that, It contains at least one of the following features: (1) The particle size of the organic composite microsphere pore-forming agent is 20-90 μm; (2) The preparation method of the organic composite microsphere pore-forming agent includes one of centrifugal spray granulation, granulation or reverse microemulsion polymerization.

3. The grinding and polishing method according to claim 1, characterized in that, The water-soluble adhesive includes at least one of cyclodextrin, dextrin, starch, hydroxymethyl cellulose, methyl cellulose, polyacrylic acid, polyacrylamide, and polyvinyl alcohol.

4. The grinding and polishing method according to claim 1, characterized in that, The second abrasive includes at least one of aluminum oxide, silicon dioxide, and cerium oxide.

5. The grinding and polishing method according to claim 1, characterized in that, The first abrasive includes at least one of diamond, silicon carbide, cubic boron nitride, zirconium oxide, and corundum.

6. The grinding and polishing method according to claim 1, characterized in that, It contains at least one of the following features: (1) The resin binder includes at least one of unsaturated polyester, epoxy resin, and polyurethane; (2) The filler includes at least one of graphite, carbon black, carbon fiber short fibers, carbon nanotubes, calcium carbonate, and calcium silicate; (3) The additives include at least one of initiator, curing agent and dispersant.

7. The grinding and polishing method according to any one of claims 1-6, characterized in that, The preparation method of the integrated grinding and polishing composite abrasive includes the following steps: S1. After mixing the raw materials of the abrasive layer, degas the mixture to obtain a mixture, and place the mixture in a molding die; S2. A substrate layer is applied to the surface of the non-grinding and polishing surface of the mixture and cured to obtain the integrated grinding and polishing composite abrasive; or, the mixture is first cured to obtain an abrasive layer, and then the substrate layer is applied to the surface of the non-grinding and polishing surface of the abrasive layer to obtain the integrated grinding and polishing composite abrasive.

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