Abrasive rotary tool and method thereof, structured abrasive article and assembly

Abstract

A rotary abrasive tool is provided, comprising a cylindrical tool body having a curved side surface and a circular facet. It also includes a compliant abrasive film wrapped around an edge connecting the curved side surface and the circular facet. The film includes a base attached to the curved side surface and a plurality of protrusions extending from the base, each protrusion having a first width at the base and a second width at an opposite end. The second width is less than the first width. A structured abrasive layer is also included disposed on the compliant abrasive film. This layer has a plurality of precisely shaped abrasive compounds arranged in a repeating pattern. Each precisely shaped abrasive compound includes a first facet that is substantially triangular, opposite a second facet that is substantially triangular, a quadrilateral surface connected to the first and second triangular faces, a cutting edge formed along one side of the quadrilateral surface, and a contact edge formed along the opposite side, the contact edge being longer than the cutting edge. The precisely shaped abrasive compounds contain ceramic abrasive particles in a binder material.

Description

Technical Field

[0001] This invention relates to grinding rotary tools and methods thereof, structured abrasive articles and components. Background Technology

[0002] When grinding industrial steel wire-reinforced glass, heat-resistant glass, or other glass substrates, or when grinding large substrates containing ceramic or metallic materials, it is important to extend the life of the abrasive pad and maintain a high cutting rate. Structured abrasives, which are abrasive compounds with multiple shapes bonded to a backing, are widely used in grinding processes. During grinding with structured abrasives, liquids, such as water or cutting fluid, are typically added to the grinding interface to extend the life of the structured abrasive. In the case of water, surfactants are also commonly used. Summary of the Invention

[0003] When the shape structure formed from the substrate is projected into the abrasive component of an abrasive material product, the microstructure of the abrasive surface becomes regular, and the load in the abrasive component is reduced. In this way, excellent finishing performance and long-term load resistance can be achieved simultaneously. However, in the case of abrasive material products used for grinding operations that apply high loads, the durability of the abrasive component remains a goal.

[0004] Therefore, this disclosure provides an abrasive material product whose abrasive components exhibit excellent durability even under high loads and long grinding operations.

[0005] Different shapes of abrasive composite structures have been found to be useful for removing materials from different substrates.

[0006] This disclosure provides a novel precision-formed abrasive compound for abrasive articles. In some embodiments herein, the abrasive article is a rotary abrasive tool having a compliant layer. The abrasive article may include a substrate and a plurality of abrasive components of various shapes projected from the substrate, wherein the abrasive components include (1) an upper layer consisting of a mixture of cured materials comprising abrasive particles dispersed in a resin and (2) a lower layer consisting of a binder-cured material comprising radiation-curable monomers and / or oligomers and a thermosetting resin.

[0007] In this document, the term "shaped abrasive compound" refers to a body composed of abrasive particles and a binder, intentionally formed into a non-random shape (e.g., pyramids, ridges, etc.) and typically having regular boundaries. Exemplary forming methods include casting and curing methods, embossing, and molding. Shaped abrasive compounds can be set on a backing according to a predetermined pattern (e.g., as an array). In some embodiments, the shaped abrasive compound is "precisely shaped." This term means that the shape of the abrasive compound is defined by relatively smooth surface sides, which are demarcated by well-defined edges with different edge lengths and by different endpoints defined by the intersection of the respective sides. The terms "definition" and "boundary" refer to the exposed surfaces and edges of each compound that define and define the actual three-dimensional shape of each abrasive compound. These boundaries are clearly visible and distinguishable when a cross-section of an abrasive article is observed under a scanning electron microscope. These boundaries distinguish one precisely shaped abrasive compound from another, even if the compounds are adjacent at their bases along a common boundary.

[0008] As described herein, the term "length" refers to the longest edge dimension of a precisely shaped abrasive compound. The term "width" refers to the next longest dimension perpendicular to the length. The term "thickness" refers to the shortest dimension perpendicular to both the length and width.

[0009] Precisely shaped abrasive compounds can be of any three-dimensional shape, resulting in at least one raised feature or depression on the exposed surface of the abrasive layer. Available shapes include, for example, cubes, prisms, pyramids (e.g., square or hexagonal pyramids), truncated pyramids, cones, and truncated cones. Combinations of abrasive compounds of different shapes and / or sizes can also be used. The abrasive layer of structured abrasives can be continuous or discontinuous.

[0010] Further details regarding structured abrasive articles with precisely shaped abrasive compounds and methods for manufacturing the same can be found, for example, in U.S. Patent Nos. 5,152,917 (Pieper et al.); 5,435,816 (Spurgeon et al.); 5,672,097 (Hoopman); 5,681,217 (Hoopman et al.); 5,454,844 (Hibbard et al.); 5,851,247 (Stoetzel et al.); and 6,139,594 (Kincaid et al.).

[0011] Typically, shaped abrasive compounds are arranged on a backing according to a predetermined pattern or array, although this is not mandatory. The shaped abrasive compounds can be arranged such that some of their working surfaces are recessed from the polishing surface of the abrasive layer.

[0012] For precision finishing applications, the density of the shaped abrasive compound in the abrasive layer is typically in the range of at least 1,000, 10,000 or even at least 20,000 abrasive compounds per square inch (e.g., at least 150, 1,500 or even 7,800 abrasive compounds per square centimeter) to include 50,000, 70,000 or even up to 100,000 abrasive compounds per square inch (including up to 7,800, 11,000 or even up to 15,000 abrasive compounds per square centimeter), although larger or smaller abrasive compound densities may also be used.

[0013] In some embodiments, the abrasive article includes a thermosetting resin between the abrasive layer and the substrate, providing adhesion to maintain the coupling between the abrasive layer and the substrate, even when subjected to heavy grinding work with high loads. Attached Figure Description

[0014] Figure 1 A perspective cross-sectional view of an abrasive material product with an abrasive component having a triangular pyramidal structure is shown.

[0015] Figure 2 A plan view of an abrasive material product featuring an abrasive component with a triangular pyramidal structure is shown.

[0016] Figures 3A-3H Perspective views of some precisely shaped structured abrasive composites according to embodiments herein are shown.

[0017] Figures 4A-4E An abrasive layer is shown formed by multiple precisely shaped abrasive compounds arranged in a repeating pattern according to embodiments herein.

[0018] Figures 5A-5H The rotating abrasive systems and tools that are particularly useful in the embodiments described herein are shown.

[0019] Figures 6A-6D A rotation tool according to embodiments herein is shown.

[0020] Figures 7A-7D The shape of the composite abrasive structure is shown in more detail in the example.

[0021] Figures 8A-8F Different deformable abrasive film patterns that can be used in rotary tools according to the embodiments herein are shown.

[0022] Figure 9 A method for forming a rotary abrasive tool for 3D abrasive operation according to embodiments herein is demonstrated.

[0023] Figure 10 This paper demonstrates a method for grinding a work surface using a 3D rotating abrasive tool according to embodiments herein.

[0024] Figure 11A , Figure 11B and Figure 11C The test results are shown in more detail in the example. Detailed Implementation

[0025] This disclosure provides an abrasive article comprising a substrate and abrasive components of a plurality of precisely shaped abrasive compounds projected from the substrate.

[0026] Figure 1 This is a cross-sectional view of an exemplary abrasive article. The abrasive article includes, for example, Figure 1 As shown, a substrate 1 and an abrasive layer 2 are present. The abrasive layer 2 is divided into an upper layer 4 for contacting the material to be abraded and a lower layer 3 adjacent to the substrate. The upper layer 4 contains resin 5 and abrasive particles 6 dispersed therein. In some embodiments, the lower layer 3 contains resin and is substantially free of or contains no abrasive particles. However, in some embodiments, the lower layer 3 may contain any abrasive particles, colorants, and coupling agents, as long as they do not adversely affect the adhesion strength between the substrate and the upper layer.

[0027] Structured abrasive articles are a specific type of coated abrasive article, typically comprising multiple shaped abrasive compounds fixed to a backing. Each shaped abrasive compound has a base in contact with the backing and a distal end extending outward from the backing. The shaped abrasive compound consists of abrasive particles dispersed in a binder (typically a polymer binder). The shaped abrasive compounds are typically arranged in a closely packed array. In a common configuration of structured abrasive articles, the shaped abrasive compounds are pyramidal (e.g., tetrahedral or square pyramidal).

[0028] Traditionally, structured abrasive products, such as the TRIZACT products offered by 3M in St. Paul, Minnesota, use pyramid-shaped abrasive compounds.

[0029] Substrate 1 can be made of any suitable material, including but not limited to: polymer films, paper, cloth, metal films, fibers, nonwoven substrates, combinations thereof, and processed products thereof. The substrate can be a flexible material. The substrate can be UV-transparent to allow the resin to cure during the manufacturing process.

[0030] In some embodiments, the substrate 1 is a polymer film, such as a polyester film. This is because polymer films have good smoothness and uniform thickness, thus allowing for high finishing precision. Polymer films can undergo an adhesion-friendly treatment to promote adhesion between the abrasive component and the substrate. However, it is explicitly understood that any suitable polymer film can be used. For example, in some embodiments, a polyurethane film may be used.

[0031] In some embodiments, a primer is used as an adhesion treatment for the polymer film, exhibiting excellent heat resistance. Other suitable treatments are also possible.

[0032] An exemplary substrate material is a polyester film. Polyester exhibits excellent mechanical strength, heat resistance, water resistance, and oil resistance. When using a polyester film, its thickness is 10 to 500 micrometers, preferably 30 to 200 micrometers, and more preferably 50 to 150 micrometers. Thicknesses within this range provide the flexibility to achieve good contact with the object being ground, as well as the strength to withstand high-load grinding operations.

[0033] In a preferred embodiment of the invention, the abrasive material product is industrially mass-produced, requiring continuous steps of forming the abrasive component, adhering it to a sheet substrate, and winding the resulting abrasive material product. Therefore, the shape structure must be adhered to the substrate in a short time. To achieve this short-term adhesion, it is preferable to at least partially cure the adhesive forming the lower layer 3 via a radiation curing mechanism to adhere it to the substrate surface. This is because the application of radiation energy can be performed quickly, and the curing speed of radiation-curable resins is very high.

[0034] In a preferred embodiment, a polymer film is used as a substrate, and an adhesive forming the lower layer 3 contacts one of its surfaces. Light is irradiated from the opposite side of the transparent polymer film to cure the adhesive and simultaneously adhere the shape structure to the substrate. The resulting sheet abrasive material product is then wound and stored.

[0035] However, it is clearly understood that other polymer films may be used in the embodiments described herein.

[0036] In some embodiments, an optional pressure-sensitive adhesive layer is present.

[0037] In some embodiments, the lower layer 3 is essentially formed of a radiation-curable liquid adhesive. Radiation-curable means that it cures at least partially by absorbing radiation energy and adheres to the substrate surface.

[0038] In some embodiments, the lower layer 3 is composed of a binder-cured material comprising radiation-curable liquid monomers and / or oligomers and a thermosetting resin. This is because, compared to the case where only radiation-curable liquid monomers and / or oligomers are used, the adhesion of the binder to the substrate is significantly improved, the abrasive components become more resistant to separation, and the durability of the abrasive material product is improved.

[0039] Radiation-curable liquid monomers and / or oligomers may include, for example, photocurable acrylic compounds known to those skilled in the art. In one embodiment, they may be selected from the group consisting of acrylic polyurethanes, acrylic epoxy resins, amino plastic derivatives having α,β-unsaturated carbonyl groups, vinyl unsaturated compounds, isocyanurate derivatives having at least one acrylate group, isocyanates having at least one acrylate group, and mixtures thereof.

[0040] Representative examples of vinyl unsaturated monomers include methacrylates, ethyl methacrylates, styrene, divinylbenzene, hydroxyethyl methacrylates, hydroxypropyl methacrylates, hydroxybutyl methacrylates, vinyltoluene, ethylene glycol dimethacrylates, polyethylene glycol dimethacrylates, hexanediol dimethacrylates, triethylene glycol dimethacrylates, trimethylolpropane trimethacrylates, glycerol trimethacrylates, pentaerythritol trimethacrylates, and pentaerythritol tetramethacrylates. Other vinyl unsaturated monomers or oligomers include monoallyl, polyallyl, and polymethallyl esters and amides of carboxylic acids, such as diallyl phthalates, diallyl adipates, and N,N-diallyl hexamethylenediamide. Other nitrogen-containing compounds include tris(2-acryloyloxyethyl) isocyanurate, 1,3,5-tris(2-methacryloyloxyethyl)-s-triazine, acrylamide, methacrylamide, N-methacrylamide, N,N-dimethylacrylamide, N-vinylpyrrolidone, and N-vinylpiperidone.

[0041] Commercially available examples of acrylated polyurethanes include those marketed under trade names such as PHOTOMER (e.g., PHOTOMER 6010 from Henkel Corp., Hoboken, New Jersey), EBECRYL (e.g., EBECRYL 220 (a hexafunctional aromatic polyurethane acrylate with a molecular weight of 1000) from UCB Radcure, Smyrna, Georgia), EBECRYL 284 (an aliphatic polyurethane diacrylate with a molecular weight of 1200 g / mol diluted with 1,6-hexanediol diacrylate), EBECRYL 4827 (an aromatic polyurethane diacrylate with a molecular weight of 1600 g / mol), EBECRYL 4830 (an aliphatic polyurethane diacrylate with a molecular weight of 1200 g / mol diluted with tetraethylene glycol diacrylate), EBECRYL 6602 (a trifunctional aromatic polyurethane acrylate with a molecular weight of 1300 g / mol diluted with trimethylolpropane ethoxytriacrylate), and EBECRYL... 840 (aliphatic polyurethane diacrylate with a molecular weight of 1000 g / mol) and SARTOMER (e.g., SARTOMER 9635, 9645, 9655, 963-B80 and 966-A80) from Sartomer Co., West Chester, Pennsylvania, and UVITHANE (e.g., UVITHANE 782) from Morton International, Chicago, Illinois.

[0042] Acrylated epoxy resins are acrylate esters of epoxy resins, such as diacrylates of bisphenol A epoxy resins. Commercially available examples of acrylated epoxy resins include those from UCB Radcure under the trade names CMD 3500, CMD 3600, and CMD 3700, and those from Sartomer Co. under the trade names CN103, CN104, CN111, CN112, and CN114.

[0043] Examples of polyester acrylates include those obtained from Henkel Corp. under the trade names PHOTOMER 5007 and PHOTOMER 5018.

[0044] Photocurable acrylic compounds typically have a (meth)acryloyl group in the molecule and a molecular weight of 70 to 700, with 80 to 600 in one example. Acrylic acid and methacrylates can be used. Specific examples of photocurable acrylic compounds are as follows.

[0045] Examples of monofunctional acrylic monomers include isoborneol acrylate, 2-hydroxyethyl (meth) acrylate, hydroxypropyl acrylate, 4-hydroxybutyl acrylate, ethylene oxide modified phenolic acrylate, cyclohexyl acrylate, tetrahydrofurfuryl acrylate, benzyl acrylate, N,N-dimethylacrylamide, N,N-diethylacrylamide, acrylmorpholine, N,N-dimethylaminopropylacrylamide, isopropylacrylamide, dimethylaminoethyl acrylate, 2-hydroxy-3-phenoxypropyl acrylate, dicyclopentenyl (meth) acrylate, benzyl (meth) acrylate, phenoxyethyl (meth) acrylate, benzyl tribromo (meth) acrylate, phenoxyethyl tribromo (meth) acrylate, biphenyl ethoxy (meth) acrylate, biphenyl epoxy (meth) acrylate, naphthyl ethoxy (meth) acrylate, fluorene epoxy (meth) acrylate, etc.

[0046] Examples of multifunctional acrylic monomers include ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, ethylene oxide-modified trimethylolpropane tri(meth)acrylate, propylene oxide-modified trimethylolpropane tri(meth)acrylate, hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, pentaerythritol tetraacrylate, pentaerythritol triacrylate, di(trimethylolpropane tetra(meth)acrylate, 2 2-Methacryloxyethyl-2-hydroxypropyl acrylate, bisphenol A di(meth)acrylate, bisphenol A tetrabromodi(meth)acrylate, bisphenol A ethoxy-modified di(meth)acrylate, bisphenol A tetrabromoethoxy-modified di(meth)acrylate, bisphenol A-epoxydi(meth)acrylate, bisphenol A-epoxyethoxy-modified di(meth)acrylate, bisphenol A-epoxytetrabromodi(meth)acrylate, bisphenol A-epoxytetrabromoethoxy-modified di(meth)acrylate, etc. In addition, mixtures of their acrylic monomers can also be used.

[0047] The photocurable acrylic compound used for the lower layer 3 can be a mixture of monofunctional and polyfunctional acrylic monomers. Polyfunctional acrylic monomers can be used for rapid curing of the liquid adhesive. However, polyfunctional acrylic monomers have high viscosity and poor compatibility with thermosetting resins. If polyfunctional acrylic monomers are used alone as the photocurable acrylic compound, it may be difficult to prepare a homogeneous adhesive mixture containing a sufficient amount of thermosetting resin, and the strength of the cured product tends to be reduced.

[0048] On the other hand, monofunctional acrylic monomers have low viscosity and excellent compatibility with thermosetting resins. Therefore, when monofunctional and polyfunctional acrylic monomers are used in combination as photocurable acrylic compounds, the viscosity of the adhesive can be reduced, the compatibility with thermosetting resins can be improved, thereby providing a uniform adhesive and increasing the strength of the cured product.

[0049] Examples of particularly preferred monofunctional acrylic monomers include isobornyl acrylate and benzyl acrylate. Examples of particularly preferred polyfunctional acrylates include trifunctional acrylates, such as trimethylolpropane triacrylate, ethylene oxide-modified trimethylolpropane tri(meth)acrylate, propylene oxide-modified trimethylolpropane tri(meth)acrylate, and tetrafunctional acrylates, such as pentaerythritol tetraacrylate.

[0050] The mixing ratio of monofunctional acrylic monomers and polyfunctional acrylic monomers is 5 to 500 parts by weight, preferably 10 to 200 parts by weight, and more preferably 20 to 100 parts by weight of polyfunctional acrylate based on 100 parts by weight of monofunctional acrylate. This weight ratio allows the viscosity of the mixed solution and the hardness of the thermosetting resin or cured product to be adjusted within an ideal range.

[0051] In some embodiments, each precisely shaped abrasive compound contains 2.5 to 3.5 weight percent of a nonionic polyether surfactant, based on the total weight of the shaped abrasive compound.

[0052] The binder in the lower layer 3 may contain a photopolymerization initiator to effectively polymerize the acrylic compound via light radiation. The type and amount of photopolymerization initiator vary depending on the type and quantity of the acrylic monomer, and their determination methods are well known to those skilled in the art.

[0053] Specific examples of photopolymerization initiators may include, as free radical polymerization initiators, benzophenone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinoacetone, camphorquinone, benzyl alcohol, benzyl alcohol methyl ether, benzyl alcohol n-propyl ether, benzyl alcohol n-butyl ether, ethylene glycol diacetate, p-methylbenzophenone, diacetyl, eosin, thionine, Michler's ketone, acetophenone, 2-chlorothioxanthone, anthraquinone, chloroanthraquinone, 2-methylanthraquinone, α-hydroxyisobutyl benzophenone, p-isopropyl-α-hydroxyisobutyl benzophenone, α,α'-dichloro-4-phenoxyacetophenone, 1-hydroxy-1-cyclohexylacetophenone, 2,2-dimethoxy-2-phenylacetophenone, methylbenzyl alcohol formate, dichlorothioxanthone, diisopropylthioxanthone, diphenyl-2-nitrofluorene disulfide, butanone, benzyl alcohol ethyl ether, tetramethylthiourea diethyl ether, etc. Sulfides, 2,2-dimethoxy-1,2-diphenyl ethyl ketone, 1-hydroxy-cyclohexyl-phenyl-ketone, 2-hydroxy-2-methyl-1-phenyl-propanone, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propanone, 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propanoyl)-benzyl]phenyl}-2-methyl-propanone, 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropanone, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1, 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-morpholino)phenyl]-1-butanone, 2,4,6-trimethylbenzoyl-diphenyl-phosphate oxide, bis(2,4,6-trimethylbenzoyl)-phenyl-phosphate oxide, etc.

[0054] The photopolymerization initiator content is from 0.1 to 20 parts by weight, and in one embodiment from 0.5 to 10 parts by weight, based on 100 parts by weight of radiation-curable liquid monomers and / or oligomers and thermosetting resins. If the amount of photopolymerization initiator is less than 0.1 parts by weight, polymerization of acrylic monomers becomes difficult even under radiation; if it exceeds 20 parts by weight, polymerization will occur even under weak light, and the storage stability of the adhesive will deteriorate.

[0055] As described above, as a component of the lower layer 3, a thermosetting resin can be used in conjunction with radiation-curable liquid monomers and / or oligomers. The thermosetting resin may have functional groups of a different type than those of the radiation-curable liquid monomers and / or oligomers. The thermosetting resin need not be radiation-curable. Thermosetting resins include those thermosetting epoxy resins known to those skilled in the art. Each molecule of a thermosetting epoxy resin has two or more epoxy groups, a molecular weight of 100 to 2,000, or 200 to 1,500, and an epoxy equivalent of 50 to 1,000, or 100 to 750. Specific examples are as follows.

[0056] These include bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, bisphenol S diglycidyl ether, tetrabromobisphenol A diglycidyl ether, resorcinol diglycidyl ether, diglycidyl phthalate, cresol phenolic polyglycidyl ether, phenolic polyglycidyl ether, fluorene diglycidyl ether, butanediol diglycidyl ether, hexanediol diglycidyl ether, cyclohexanediol diglycidyl ether, trimethylolpropane triglycidyl ether, glycerol polyglycidyl ether, ethylene-polyethylene glycol diglycidyl ether, sorbitol polyglycidyl ether, etc. Mixtures of these can also be used.

[0057] The thermosetting epoxy resin used as component 3 in the lower layer may include cresol phenolic epoxy resin, bisphenol A epoxy resin, or mixtures thereof. Cresol phenolic epoxy resin is particularly hard and is preferred when heat resistance is required. Bisphenol A epoxy resin is liquid and readily mixable with acrylic monomers and / or oligomers, and is preferred when relative flexibility is required. The hardness can be adjusted by mixing the two in appropriate proportions. Both exhibit excellent adhesion and strength, and have good compatibility with acrylic monomers and / or oligomers.

[0058] In one embodiment of the abrasive material product disclosed herein, the epoxy resin includes cresol phenolic epoxy resin, bisphenol A epoxy resin, or mixtures thereof, and the acrylic compound includes polyfunctional acrylates.

[0059] The adhesive in the lower layer 3 may contain a curing agent for curing the thermosetting epoxy resin. The type and amount of curing agent vary depending on the type and quantity of the thermosetting epoxy resin, and the methods for determining this are well known to those skilled in the art.

[0060] In one embodiment, each molecule of the curing agent contains two or more thermally reactive epoxy functional groups, with a molecular weight of 100 to 2,000, and in another embodiment, 200 to 1,500. Examples of thermally reactive epoxy functional groups may include amino, amide, and thiol groups. Amines, amides, acid anhydrides, phenols, thiol compounds, tertiary amines, Lewis acid complexes, etc., are commonly used as curing agents.

[0061] Specific examples of curing agents include aliphatic amines having 4 to 20 carbon atoms, such as hexamethylenediamine and diethylenetriamine; aromatic amines having 6 to 20 carbon atoms, such as m-phenylenediamine, diaminodiphenylmethane, and diaminodiphenyl sulfone; dicyandiamine and its derivatives having 2 to 20 carbon atoms; organic acid hydrazides having 3 to 30 carbon atoms, such as phenylbiguanide and phenylbiguanide oxalate; BF3 complexes having 2 to 10 carbon atoms, such as BF3-monoethylamine complexes and BF3-diethylamine complexes; imidazole derivatives having 4 to 30 carbon atoms, such as 2-methylimidazole, 2-ethyl-4-methylimidazole, and 2-phenylimidazole; diaminomaleimide and its derivatives having 4 to 20 carbon atoms; melamine resins and their derivatives; acid anhydrides having 8 to 40 carbon atoms, such as phthalic anhydride and pyromellitic anhydride; bismaleimide, etc.

[0062] The curing agent can be an amine derivative, dicyandiamine, or its derivatives with a molecular weight of 80 to 200.

[0063] The amount of curing agent used, for example in the case of imidazole derivatives, is 0.5 to 20 parts by weight based on 100 parts by weight of radiation-curable liquid monomers and / or oligomers and thermosetting resins, and in one embodiment, it is 1 to 10 parts by weight. If the amount of curing agent is less than 0.5 parts by weight, the thermosetting epoxy resin becomes difficult to cure, and the strength of the abrasive part decreases; if it exceeds 20 parts by weight, the hardness of the cured epoxy resin decreases.

[0064] As the binder for the lower layer 3, it preferably contains 30 to 1,000 parts by weight of a light-curing acrylic compound. In one embodiment, it contains 50 to 500 parts by weight of the light-curing acrylic compound based on 100 parts by weight of the thermosetting resin. If the amount of the light-curing acrylic compound is less than 30 parts by weight, the lower layer 3 becomes difficult to defluidize during production; if it exceeds 1,000 parts by weight, the strength of the lower layer 3 may decrease.

[0065] In one embodiment of the abrasive material product disclosed herein, the radiation-curable monomers and / or oligomers in the lower layer are acrylic compounds, and the thermosetting resin is an epoxy resin containing 50 to 500 parts by weight of acrylic compound based on 100 parts by weight of epoxy resin.

[0066] In particular, when a mixture of monofunctional and trifunctional acrylic monomers is used as the photocurable acrylic compound of the lower layer 3, and bisphenol A diglycidyl ether and / or cresol phenolic polyglycidyl ether is used as the thermosetting acrylic compound, it is preferable to adjust the amount of the photocurable acrylic compound to 100 to 200 parts by weight, particularly 120 to 180 parts by weight, based on 100 parts by weight of the thermosetting resin, in order to improve adhesion to the substrate surface.

[0067] In one embodiment of the abrasive material product disclosed herein, the acrylic compound is a mixture of monofunctional and polyfunctional acrylates.

[0068] Furthermore, in one embodiment of the abrasive material product disclosed herein, the mixture comprises 100 parts by weight of monofunctional acrylate and 20 to 100 parts by weight of polyfunctional acrylate.

[0069] The upper layer 4 consists of a cured material comprising a mixture of abrasive particles 6 dispersed in resin 5. In other words, the upper layer 4 is formed by curing a slurry containing multiple abrasive particles dispersed in an uncured or ungelled resin.

[0070] The size of the abrasive particles ranges from 0.01 to 1 micrometer for final finishing grinding, with 0.01 to 0.5 micrometers in one embodiment and 0.01 to 0.1 micrometers in another embodiment; and from 0.5 to 20 micrometers for rough grinding, with 0.5 to 10 micrometers in one embodiment. When grinding brittle materials, the size of the abrasive particles can be from 0.5 to 100 micrometers.

[0071] Examples of abrasive particles suitable for fixed abrasive pads include cubic boron nitride, fused alumina, ceramic alumina, heat-treated alumina, white fused alumina, black silicon carbide, green silicon carbide, titanium diboride, boron carbide, silicon nitride, tungsten carbide, titanium carbide, diamond, cubic boron nitride, cerium oxide, chromium oxide, hexagonal boron nitride, alumina zirconium, iron oxide, cerium oxide, garnet, alumina zirconium, alumina-based sol-gel derived abrasive particles, and mixtures thereof. Alumina abrasive particles may contain metal oxide modifiers. Examples of alumina-based sol-gel derived abrasive particles can be found in U.S. Patent Nos. 4,314,827; 4,623,364; 4,744,802; 4,770,671; and 4,881,951, all of which are incorporated herein by reference. Diamond and cubic boron nitride abrasive particles may be monocrystalline or polycrystalline. Particularly preferred examples are diamond, cubic boron nitride, alumina, and silicon carbide for rough grinding, and silica and alumina for finish grinding. Furthermore, in some embodiments, agglomerates of any of the above-described abrasive particles may be used, such as those described in U.S. Patent 5,039,311, issued August 13, 1991. Other examples of suitable inorganic abrasive particles include silica, iron oxide, chromium oxide, cerium oxide, zirconium oxide, titanium oxide, tin oxide, and γ-alumina.

[0072] When abrasive materials are used in grinding operations that apply high loads, the abrasive particles need to have high toughness. Therefore, the preferred abrasive particles are fused alumina or diamond particles, especially diamond particles.

[0073] The resin is cured or gelled to form an abrasive component. In one embodiment, examples of the resin may include phenolic resins, amino plastic resins, polyurethane resins, epoxy resins, acrylic resins, polyester resins, vinyl resins, melamine resins, acrylic isocyanurate resins, urea-formaldehyde resins, isocyanurate resins, acrylic polyurethane resins, acrylic epoxy resins, and mixtures thereof. Resorcinol phenolic resins are particularly preferred.

[0074] Amino plastic monomers have at least one suspended α,β-unsaturated carbonyl group. These unsaturated carbonyl groups can be acrylate, methacrylate, or acrylamide-type groups. Examples of such materials include N-(hydroxymethyl)-acrylamide, N,N'-oxomethylenebisacrylamide, phthaloylacrylmethylphenol, acrylmethylphenolic resins, and combinations thereof.

[0075] In one embodiment of the abrasive material product disclosed herein, the resin in the upper layer comprises phenolic resin.

[0076] The resin in the upper layer may be radiation-curable. The resin may be at least partially radiation-curable or at least partially polymerizable. In one embodiment, a radiation-curable liquid monomer and / or oligomer is used in the lower layer 3. Depending on the type of resin used, energy sources such as infrared, electron beam, ultraviolet radiation, and visible light radiation may be used.

[0077] The weight ratio of abrasive particles to resin is typically in the range of about 150 to 1000 parts abrasive particles to 100 parts resin, and in one embodiment, it is in the range of about 200 to 700 parts abrasive particles to 100 parts resin. This ratio varies depending on the size of the abrasive particles, the type of resin, and the intended use of the abrasive material product.

[0078] The mixture that makes up the upper layer may contain materials other than abrasive particles and resin. For example, conventional additives such as coupling agents, wetting agents, dyes, pigments, plasticizers, fillers, release agents, grinding aids, and mixtures thereof.

[0079] The mixture described above may contain a coupling agent. Adding a coupling agent can significantly reduce the coating viscosity of the slurry used to form the abrasive component. Examples of preferred coupling agents for this disclosure include organosilanes, zirconium aluminates, and titanates. The amount of coupling agent is typically less than 5% of the total weight of the abrasive component, and in one embodiment less than 1%.

[0080] Next, the morphology of the precisely shaped abrasive composite structure projected from a substrate will be described. The term "precisely shaped" refers to an abrasive composite structure formed in a predetermined shape. As long as the shape is artificially formed and repeatable, it is not necessary to specify the shape of the projection. However, the shape is not a random shape formed by natural processes. In one embodiment, multiple shape structures have substantially the same shape, and their arrangement in a plane is regular. In the embodiments described herein, the precisely shaped abrasive composite is formed using a mold, such that the precisely shaped abrasive composite has a structure similar to the interior of a corresponding mold cavity or groove.

[0081] In some embodiments, multiple precisely shaped abrasive compounds are formed at the same height from the substrate surface. However, it is explicitly considered that in some embodiments, adjacent precisely shaped abrasive compounds may differ in height or shape. In the embodiments described herein, the abrasive layer 2 comprises a repeating pattern of precisely shaped abrasive compounds 7. This pattern may include the same precisely shaped abrasive compounds arranged repeatedly along the length and width of the substrate 1, for example, as shown below. Figure 2 As shown. However, it is explicitly considered that in some embodiments, a precision-formed abrasive compound having a first shape may be alternated with a precision-formed abrasive compound having a second shape. Other patterns, such as those comprising three or more shapes, are also explicitly considered.

[0082] In some embodiments herein, the shape of the precision-formed abrasive compound 7 is such that the cross-section parallel to the substrate has a smaller surface area at a greater distance from the substrate, for example, the area of ​​the cross-section increases as the precision-formed abrasive compound 7 wears. In some embodiments, the cross-section is a quadrilateral cross-section. In some embodiments, the cross-section is a rectangular or substantially rectangular cross-section. In some embodiments, the cross-section is a trapezoidal cross-section.

[0083] Figure 1 Several precision-formed abrasive compounds 7 with essentially identical triangular pyramid shapes are shown, arranged in a plane as follows: Figure 2 The pattern shown is regular.

[0084] exist Figure 1 In this context, the symbol 's' represents the height of the upper layer of the shape structure. The symbol 's' ranges from 5% to 95% of the shape structure height 'h', and in one embodiment, it ranges from 10% to 90%. However, although... Figure 1 One embodiment is shown in which only a portion of the precision-formed abrasive compound contains abrasive particles, but it is explicitly considered that in other embodiments, the entire volume of the precision-formed abrasive compound contains abrasive particles.

[0085] Figure 2 A plan view of an abrasive material product featuring a triangular pyramid-shaped abrasive component is shown. Figure 2In this context, the symbol "o" represents the length of the bottom line of the shape structure. The symbol "p" represents the distance between the vertices of the shape structure. The symbol "o" is, for example, in the range of 5 to 1000 micrometers, and in one embodiment in the range of 10 to 500 micrometers. The symbol "p" is, for example, in the range of 5 to 1000 micrometers, and in one embodiment in the range of 10 to 500 micrometers.

[0086] Although Figure 1-2 An example of a known shape of a precision-formed abrasive compound is shown, but it should be noted that Figures 11 and 12a-12g of U.S. Patent 9,919,406, issued March 20, 2018, show many other shapes.

[0087] Some precision-formed abrasive composite structures have been used before. Figure 1-2 Tetrahedral abrasive composites are shown. For example, U.S. Patent 9,919,406, issued March 20, 2018, shows a variety of shape options for precision-formed abrasive composites—triangular prisms in Figures 3-4, and some shorter flat-topped structures in Figures 11-12. U.S. Patent 8,425,278, issued April 23, 2013, shows crown-shaped abrasive composites.

[0088] U.S. Patent 9,415,480, issued on August 16, 2016, describes another precision-formed abrasive composite structure that has historically performed well in grinding glass substrates.

[0089] However, the new shape shown in Figures 3-4 has been surprisingly discovered, similar to, for example... Figure 1-2 Compared to trapezoidal designs, crown designs in U.S. Patent 8,425,278, or planar triangular shapes (as discussed in U.S. Patent 9,919,406), the cutting rate is significantly improved.

[0090] Figures 3-4 show perspective views of a precision-shaped structured abrasive compound according to embodiments of this document. Among other applications, embodiments of this document include precision-shaped abrasive compounds particularly suitable for grinding glass substrates. Historically, planar precision-shaped abrasive compounds have been used for grinding glass substrates. Past attempts to increase the cutting rate have involved changing the abrasive particle concentration, abrasive particle size, and abrasive compound structure. Larger abrasive particles can achieve higher cutting rates but result in rougher surfaces. However, surprisingly, by controlling the formulation, force, speed, and time, the structure of Figure 3-4 results in a significantly higher cutting rate. The improved cutting rate is evident in all three directions of use—forward, backward, and transverse patterns (e.g., the angle at the channels between rows of abrasive compound structures).

[0091] Figures 3A-3H Some precision-formed abrasive composites according to embodiments herein are shown. Figure 3A A precision-formed abrasive composite 200 according to embodiments herein is illustrated. The composite 200 may have a base surface (on... Figure 3A (Not visible in the image), this base surface is coupled to the substrate. The base surface can be defined by a base length of 202 and a base width of 208. Rake surface (in...) Figure 3A (Not visible in the middle) is defined by the rake face length 214. The abrasive compound 200 can also be defined by the relief surface 204. Each of the three surfaces is coupled to the other two to form two substantially triangular surfaces opposite each other. For example, the base surface is coupled to the relief surface 204 along the first base edge represented by the base width 208. The base surface is coupled to the second base edge opposite to the first base edge (in the middle). Figure 3A (Not visible in the middle) is coupled to the rake surface. Similarly, the relief surface is coupled to the base surface along the edge of the first relief surface. Along the second relief edge opposite to the first relief edge, the relief surface is coupled to the rake surface. The rake surface is coupled to the base surface along the edge of the first rake surface and to the relief surface along the edge of the second rake surface.

[0092] The base width 208 can be the same as the width of the rake face, for example, making the base face rectangular. In some embodiments, the rake face has a different width than the base width 208, for example, making the base face trapezoidal. The rake face can have a longer width, making the precision-shaped abrasive compound 200 wider at the rake face end, or it can have a shorter width, making the precision-shaped abrasive compound wider at the relief face end.

[0093] The rake face and the relief face 204 meet along surface 206. Surface 206 is configured to contact the working surface during abrasive operation. In some embodiments, surface 206 may be... Figure 3A The edge 206 is shown in the diagram. However, it is explicitly considered that surface 206 can also have width. For example, with the use and wear of the abrasive compound 200, edge 206 will wear down to contact surface 206 with a rectangular profile.

[0094] Abrasive compound 200 in Figure 3A The orientation of the coupling between the base surface and the working surface is shown in the diagram. During operation, the abrasive compound 200 contacts the working surface along the contact surface 206 and moves along the machine direction 240. A rake angle 210 is formed between the rake face and the surface, and a relief angle 212 is formed between the relief face 204 and the surface.

[0095] The abrasive compound 200 has a height 220 from the contact surface 206 to the base surface.

[0096] Figure 3B-3H Several additional embodiments of the abrasive compound 200 are shown, in which one or more shape parameters are consistent with... Figure 3AThe embodiments shown herein differ from those described herein. It is explicitly understood that the different shape options shown herein can also be combined. For example, rake angles can be increased or decreased, and textures can be added to the contact surface according to the embodiments herein. Figure 3B-3H The examples provided are for illustrative purposes only and are not intended to represent the full range of abrasive compound shapes considered herein.

[0097] Figure 3B An example embodiment of a precision-formed abrasive compound 200 is shown, wherein the length of its contact surface 206 is much smaller than its base width 208, for example, having a base edge to contact edge ratio greater than 1. Increasing the base edge to contact edge ratio can offer several advantages. For example, abrasive debris (e.g., grinding chips) is generated during abrasive operation and can accumulate on the surface of the abrasive article, reducing its effectiveness over time. Increasing the base edge to contact edge ratio increases the volume between adjacent precision-formed abrasive compounds 200, which may allow abrasive debris to be more easily removed from the grinding zone. Furthermore, increasing the base edge to contact edge ratio may also increase the pressure applied along the contact surface when force is applied.

[0098] In the embodiments described herein, the base edge to contact edge ratio is greater than or equal to 1. In some embodiments, the base edge to contact edge ratio is greater than or equal to 1.2. In some embodiments, the base edge to contact edge ratio is greater than or equal to 1.5. In some embodiments, the base edge to contact edge ratio is greater than or equal to 1.8. In some embodiments, the base edge to contact edge ratio is greater than or equal to 2.0. In some embodiments, the base edge to contact edge ratio is greater than or equal to 2.5.

[0099] Figure 3C One embodiment is shown where the base edge to contact edge ratio is significantly higher, such that contact surface 206 is the vertex where the mitigation surface, the rake surface, and the triangular surface intersect. Although Figure 3C An embodiment is shown in which the contact surface 206 is a point, but it is explicitly considered that the contact surface 206 may have a circular surface.

[0100] Figure 3C An embodiment is also shown in which the contact surface 206 is asymmetrical with respect to the base surface 208. Figures 3A-3B The diagram shows that the mitigation and raking surfaces are regular trapezoids with a set of parallel sides (contact surface and base edge) and a set of non-parallel sides, with adjacent base edges having substantially the same angle. However, it is explicitly considered that other trapezoidal shapes are possible— Figure 3COne embodiment is shown where the rake face includes a right angle along the edge 224 of the rake face, such as the edge where the rake face intersects the base surface. In the illustrated embodiment, at least one triangular facet of the abrasive compound also includes a right angle, such that the contact surface 206 is substantially aligned with a corner of the base surface. However, it is explicitly considered that the contact surface 206 may be positioned at other locations on the base surface. In some embodiments, the abrasive compound has a contact surface 206 aligned with the center of the rake face edge 224. In other embodiments, the abrasive compound has a contact surface 206 that is off-center from the rake face edge 224.

[0101] Figure 3D One embodiment is shown, wherein the cutting surface 206 has a texture 224. The cutting surface 260, in... Figure 3D In one embodiment, a jagged texture is included, consisting of multiple small peaks and valleys. However, it is explicitly considered that other shapes may be suitable for texture 224, such as circular peaks, other polygonal structures, sine waves, random bump features, etc. Texture 226 may also include other patterned or random structures.

[0102] Texture 224 may have a texture height 226, measured as the difference between the highest and lowest points of texture 224. In some embodiments, the ratio of texture height to abrasive compound height may be less than 0.5. In some embodiments, the ratio of texture height to abrasive compound height may even be less than 0.4. In some embodiments, the ratio of texture height to abrasive compound height may even be less than 0.3. In some embodiments, the ratio of texture height to abrasive compound height may even be less than 0.2. In some embodiments, the ratio of texture height to abrasive compound height may even be less than 0.1. In some embodiments, the ratio of texture height to abrasive compound height may even be less than 0.05.

[0103] Figure 3E An embodiment of a truncated precision-shaped abrasive compound 200 is shown, its shape such that the mitigation surface 204 is spaced apart from the base surface. The precision-shaped abrasive compound no longer has two triangular faces, but instead has two opposing trapezoidal faces. The abrasive compound 200 also includes a trailing surface 232 with a height 228. Although Figure 3E A trailing surface 232 is shown that appears to be rectangular, but it is explicitly considered that in some embodiments the trailing surface 232 is trapezoidal.

[0104] Figure 3F-3H Examples of precision-formed abrasive compounds with different rake angles are shown. Figure 3F An example of a precision-formed abrasive compound with a positive rake angle of 242 is shown. Figure 3G An example of a precision-formed abrasive compound with a negative rake angle of 244 is shown. Figure 3GAn example of a precision-formed abrasive compound with a neutral rake angle of 246 is shown.

[0105] However, although Figure 3F-3H Examples of rake angles are shown, but it is explicitly understood that the precision-formed abrasive compound 200 according to embodiments herein can have a range of positive or negative rake angles 210. For example, the rake angle between the abrasive compound and the working surface is between 30° and 150°, or between 40° and 140°, or between 50° and 130°, or between 60° and 120°, or between 70° and 110°, or between 80° and 100°. Angle 210 can be at least 30°, or at least 40°, or at least 50°, or at least 60°, or at least 70°, or at least 80°, or at least 90°, or at least 100°, or at least 110°, or at least 120°, or at least 130°, or at least 140°, or at least 150°.

[0106] The precision-formed abrasive compounds described herein have intentionally shaped faces, for example, formed using a mold. The faces are described according to the polygons they represent. However, it is explicitly considered that, for example, the edges or corners of the precision-formed abrasive compounds described herein may be rounded. Thus, a face with a "generally triangular" or "generally trapezoidal" shape may resemble a trapezoid whose three corners, one or more of which are rounded. In some embodiments, the corners may be intentionally rounded. In other embodiments, the roundness of the edges or tips may be due to limitations of mold forming, such as the collection of release agent in mold recesses, or tooling limitations of mold forming.

[0107] The precision-shaped abrasive compound 200 can be partially defined by its aspect ratio—the ratio of its thickness (e.g., the average length between the contact surface 206 and the base width 208) to the base length 202. The precision-shaped abrasive compound 200 can have an aspect ratio of thickness to length greater than 1 but less than 3. In some embodiments, the aspect ratio may be less than 2, even less than 1.9, even less than 1.8, even less than 1.7, even less than 1.6, even less than 1.5.

[0108] In some embodiments, the base length 202 of the precision-forming abrasive compound 200 is between 500 and 2000 micrometers. In some embodiments, the base length 202 is between 700 and 1500 micrometers. In some embodiments, the base length 202 is between 800 and 1200 micrometers. In some embodiments, the height 220 of the precision-forming abrasive compound 200 is between 300 and 1200 micrometers. In some embodiments, the height 220 is between 500 and 900 micrometers. In some embodiments, the height 220 is between 500 and 700 micrometers. In some embodiments, the length of the cutting surface 206 is between 400 and 900 micrometers. In some embodiments, the length of the cutting surface 206 is between 500 and 800 micrometers. In some embodiments, the length of the cutting surface 206 is between 600 and 700 micrometers. In some embodiments, the base width 208 is between 500 and 2000 micrometers. In some embodiments, the base width 208 is between 700 and 1500 micrometers. In some embodiments, the base width 208 is between 900 and 1000 micrometers.

[0109] In some embodiments, the relief angle 212 is between 15-60°, or between 20-50°, or between 30-40°.

[0110] It is important to note that, compared to previous designs (e.g.) Figure 1-2 and Figures 7B-7D Compared to the design of the precision-formed abrasive compound 200, it has only one plane of symmetry—passing through surface 204 from the midpoint of edge 208 and the midpoint of edge 206. However, it is explicitly considered that in some embodiments, the precision-formed abrasive compound 200 does not have a plane of symmetry.

[0111] The precision-shaped abrasive compound 200 has a rectangular cutting surface 206, unlike at least some previous abrasive compound shapes used for grinding glass, rather than a planar or circular grinding surface seen in some previous abrasive compound shapes. Circular surfaces or cutting tips are typically used.

[0112] Figures 4A-4E An abrasive layer formed from multiple precisely shaped abrasive compounds arranged in a repeating pattern according to embodiments herein is shown. It is explicitly considered that, although... Figures 4A-4C Three example patterns are shown, but many other patterns are possible according to the embodiments described herein.

[0113] Figure 4A An abrasive layer 250 formed of a plurality of precision-formed abrasive compounds 200 is shown, each abrasive compound having a cutting surface 206. In some embodiments, the plurality of precision-formed abrasive compounds 200 are formed as a single structure with a base layer 260.

[0114] Abrasive layer 250 is formed of precision-shaped abrasive compounds 200, such that each precision-shaped abrasive compound 200 is adjacent to the next precision-shaped abrasive compound 200. In some embodiments, abrasive compounds 200 are spaced apart from adjacent compounds. In other embodiments, as shown by spacing 252, adjacent abrasive compounds contact each other along a base length and / or base width. As described above, precision-shaped abrasive compounds having a cutting surface 206 shorter than the relief surface length 222 form a volume between adjacent abrasive compounds, which can serve as a channel to allow grinding fluid to enter the grinding contact area and / or allow fluid to remove debris from the grinding contact area. In some embodiments, a consistent spacing 252 exists between precision-shaped abrasive compounds 200. Spacing 252 may be less than 10% of the base length 202, or less than 8% of the base length 202, or less than 6% of the base length 202, or even less than 4% of the base length 202.

[0115] In some embodiments, the cutting surface 206 of the precision-formed abrasive composite structure 250 exists in a plane parallel to the substrate surface, occupying a large portion of the surface area of ​​the abrasive material product. The vertex height 220 of the precision-formed abrasive composite, measured from the substrate surface, may be between 300 and 1000 micrometers in some embodiments, between 400 and 900 micrometers, or between 500 and 800 micrometers. The variation in vertex height is preferably within 20% of the average height of the shape structure, more preferably within 10%.

[0116] As described above, the precision-forming abrasive compound 200 typically consists of abrasive particles in a resin binder. It should be noted that, in at least some embodiments herein, the abrasive particles do not extend beyond the surface of the shape structure. That is, the shape structure consists of a smooth surface. For example, the surface constituting the shape structure has a surface roughness Ry of 2 micrometers or less, and in one embodiment, 1 micrometer or less.

[0117] In its shape and structure, the cutting edge 206 exhibits grinding functionality. During the use of the abrasive material product for grinding, the precision-formed abrasive compound decomposes starting from the cutting edge 206, resulting in unused abrasive particles. Therefore, it may be preferable to increase the concentration of abrasive particles present in the upper layer 4 of the precision-formed abrasive compound 200 to enhance the cutting performance of the abrasive material product. This is because the improved cutting performance of the abrasive material product makes it suitable for grinding hard materials.

[0118] In some embodiments, the precision-formed abrasive compound 200 comprises a series of discrete layers having an increasing abrasive particle concentration from the base edge 202 to the cutting edge 206. In some embodiments, at least two layers, or at least three layers, or even at least four layers are present. In some embodiments, discrete layers with different abrasive particle concentrations are not present, but the abrasive particle concentration generally increases from the base edge 202 to the cutting edge 206.

[0119] Figure 4A One embodiment is shown in which each precision-formed abrasive compound has the same orientation—for example, the cutting surface 206 and base length 202 of a precision-formed abrasive compound are substantially parallel. However, it is explicitly understood that other patterns are possible. The abrasive layer 250 comprises a plurality of precision-formed abrasive compounds 200, which are precisely positioned relative to each other. Precise positioning can be used to create different abrasive compound patterns.

[0120] For example, Figure 4B One embodiment is shown in which the abrasive compound in abrasive layer 252 has a relative orientation in adjacent columns. It is explicitly considered that the abrasive compound can also have a relative orientation through adjacent rows.

[0121] Figure 4C An embodiment is shown in which the abrasive compound in the abrasive layer 254 has relative orientations in adjacent rows and columns, such as a chessboard.

[0122] However, it is explicitly considered that other patterns can be achieved using the abrasive compounds described herein. In the embodiments shown in Figures 3-4, the base surface is rectangular—for example, having a base length 202 that is longer than the base width 208. However, it is explicitly considered that in some embodiments, the base length 202 and the base width 208 may be substantially the same or equal, resulting in a square profile for the base surface. In such embodiments, the orientations of adjacent abrasive compounds may be offset by 90°, 180°, or 270°, in addition to their relative orientations, through adjacent rows, columns, or both.

[0123] also, Figures 4A-4C The abrasive layers are shown to have distinct rows and columns because the basal surfaces of adjacent abrasive compounds are aligned. However, it is explicitly considered that abrasive compounds can be placed such that they are offset within adjacent rows or columns.

[0124] Figure 4DAn embodiment is shown in which the abrasive compounds of adjacent columns are offset relative to each other by an offset of 260, which can be represented as a portion of the base length 202. For example, the offset can be greater than or equal to 5% of the base length 202, greater than or equal to 10% of the base length 202, greater than or equal to 15% of the base length 202, greater than or equal to 20% of the base length 202, greater than or equal to 25% of the base length 202, greater than or equal to 30% of the base length 202, greater than or equal to 35% of the base length 202, greater than or equal to 40% of the base length 202, greater than or equal to 45% of the base length 202, greater than or equal to 50% of the base length 202, greater than or equal to 55% of the base length 202, greater than or equal to 60% of the base length 202, greater than or equal to 65% of the base length 202, greater than or equal to 70% of the base length 202, greater than or equal to 75% of the base length 202, greater than or equal to 80% of the base length 202, greater than or equal to 85% of the base length 202, greater than or equal to 90% of the base length 202, and greater than or equal to 95% of the base length 202.

[0125] Similarly, the offset can be less than or equal to 95% of the base length 202, less than or equal to 90% of the base length 202, less than or equal to 85% of the base length 202, less than or equal to 80% of the base length 202, less than or equal to 75% of the base length 202, less than or equal to 70% of the base length 202, less than or equal to 65% of the base length 202, less than or equal to 60% of the base length 202, less than or equal to 55% of the base length 202, less than or equal to 50% of the base length 202, less than or equal to 45% of the base length 202, less than or equal to 40% of the base length 202, less than or equal to 35% of the base length 202, less than or equal to 30% of the base length 202, less than or equal to 25% of the base length 202, less than or equal to 20% of the base length 202, less than or equal to 15% of the base length 202, less than or equal to 10% of the base length 202, and less than or equal to 5% of the base length 202.

[0126] In addition, although Figure 4D One embodiment is shown where the abrasive compounds in adjacent columns have relative orientations and column offsets, but other combinations of features are explicitly possible. For example, the abrasive compounds in adjacent rows could have an offset of 260 degrees, and all abrasive compounds could have the same orientation. Other combinations are explicitly possible.

[0127] Figure 4E A side view of an abrasive layer is shown, containing abrasive composites of various shapes. Although Figures 4A-4D An example of an abrasive compound using a single shape in an abrasive layer is shown, but it is explicitly understood that different shapes can be used. Different shapes can be arranged in repeating patterns in rows and / or columns. Figure 4E In the illustrated embodiment, the two abrasive compounds have the same base length, although it is clearly understood that other embodiments are possible.

[0128] Different shapes may allow abrasive articles with abrasive layers to have different abrasive properties in different directions. For example, when used in the first machine direction 266, the abrasive compound has a rake angle 264. If used in the opposite direction, the abrasive compound has a rake angle 262. Combinations of different directions and different shapes may allow for finer adjustments of the abrasive layer to suit different applications.

[0129] Precision-shaped abrasive compounds and abrasive layers containing these compounds can be suitable for many different abrasive applications. The ability to customize the composition—for example, by using different binder materials and / or abrasive particles—makes the precision-shaped abrasive compounds described herein versatile. Diamond-containing abrasive tools can be used to improve surface finishing of peripheral and feature edges during cover glass manufacturing. Such diamond abrasive tools include metal-bonded diamond tools, such as coated, sintered, and brazed metal-bonded diamond tools. Metal-bonded diamond tools may offer relatively high durability and efficient cutting rates, but can leave microcracks in the glass. These microcracks are stress points that can become fracture initiation points, significantly reducing the strength of the finished cover glass below its potential fracture resistance.

[0130] However, while examples of cover glass processing are described in detail below, it is clearly considered that precisely shaped abrasive compounds and abrasive compound layers like those described in Figures 3 and 4 may also be useful in other applications. For example, micro-finished films typically contain precisely shaped abrasive compounds and may also benefit from containing precisely shaped abrasive compounds included in the embodiments described herein.

[0131] To improve the strength and / or appearance of cover glass, polishing can be performed after grinding the machined edges, for example using cerium oxide (CeO)-based coolants, to remove grinding and machining marks from the cover glass. However, this edge polishing can be time-consuming for cover glass, potentially taking several hours to provide the required surface finish to all edges. For example, polishing a single cover glass may require multiple steps to effectively polish all edges, including perimeters, holes, and corners. Polishing machines can be relatively large and expensive, and specific to the features being polished. Therefore, cover glass production may involve multiple parallel polishing lines, each containing multiple polishing machines to provide the required cover glass production capacity. Reducing processing time would allow for increased throughput per polishing line.

[0132] Furthermore, inconsistent polishing slurries can lead to unpredictable and imprecise polishing of the cover glass. Polishing can also result in unwanted corner rounding, which in turn affects the relatively accurate shape provided by the grinding operation. Generally, longer polishing times provide better surface finish, but also greater rounding and lower dimensional accuracy of the final cover glass. Reducing processing time to achieve the required surface finish quality for the cover glass not only reduces production time but also provides more precise dimensional control in cover glass production. The abrasive compounds and tools disclosed herein may help reduce processing time in cover glass production.

[0133] Figure 5A-5G A rotating abrasive system, substrate, and tool are shown, among which the embodiments described herein may be particularly useful. Figure 5A System 310 is shown, including a rotary machine 323 and a rotary machine controller 330. The controller 330 is configured to send control signals to the rotary machine 323 to cause the rotary machine 323 to machine, grind, or abrasive the component 324 using a rotary tool 328 mounted in the spindle 326 of the rotary machine 323. For example, the component 324 could be a cover glass, such as... Figure 5C The cover glass in the middle. In one example, rotary machine 323 can represent a CNC machine tool, such as a three-axis, four-axis, or five-axis CNC machine tool, capable of performing routing, turning, drilling, milling, grinding, abrasive, and / or other machining operations. Controller 330 can include a CNC controller that issues instructions to spindle 326 to machine, grind, and / or abrasive the component 324 using one or more rotary tools 328. Controller 330 can include a general-purpose computer running software, and such a computer can be combined with the CNC controller to provide the functionality of controller 330.

[0134] Component 324 is mounted on platform 338 in a manner that facilitates precise machining by rotary machine 323. Workpiece fixture 318 secures component 324 to platform 338 and precisely positions component 324 relative to rotary machine 323. Workpiece fixture 318 also provides a reference position for the control program of rotary machine 323. While the technology disclosed herein can be applied to workpieces of any material, component 324 can be a cover glass for electronic devices, such as the cover glass for a smartphone touchscreen.

[0135] exist Figure 5AIn one example, the rotary tool 328 is shown to include an abrasive surface 329. In this example, the abrasive surface 329 can be used to improve the surface finish of machined features in component 324, such as holes and edge features in the cover glass. In some examples, different rotary tools 328 can be used to iteratively improve the surface finish of machined features. For example, system 310 can be used to provide a coarser grinding step using a first rotary tool 328 or a set of rotary tools 328, followed by a finer abrasive step using a second rotary tool 328 or a set of rotary tools 328. In the same or different examples, a single rotary tool 328 may include different levels of abrasive to facilitate iterative grinding and / or abrasive processes using fewer rotary tools 328. Each of these examples may reduce the cycle time for finishing and polishing post-machined features of the cover glass.

[0136] In some examples, after grinding and / or abrasive application using System 310, a separate polishing system can be used to polish the cover glass to further improve the surface finish. Generally, the better the surface finish before polishing, the less time is required to achieve the desired surface finish after polishing.

[0137] To abrade the edges of component 324 using system 310, controller 330 can instruct spindle 326 to precisely apply abrasive surface 329 to one or more features of component 324 while spindle 326 rotates rotary tool 328. Instructions may include, for example, instructions to precisely follow the contours of features of component 324, using the abrasive surface 329 of a single rotary tool 328, and iteratively applying the abrasive surfaces 329 of multiple rotary tools 328 to different features of component 324.

[0138] In the illustrative example, the base layer of the abrasive surface 329 can be made of a polymeric material. For example, the base layer can be made of thermoplastics such as polypropylene, polyethylene, polycarbonate, polyurethane, polytetrafluoroethylene, polyethylene terephthalate, polyethylene oxide, polysulfone, polyetherketone, polyetheretherketone, polyimide, polyphenylene sulfide, polystyrene, polyoxymethylene, etc.; thermosetting plastics such as polyurethane, epoxy resin, phenolic resin, melamine resin, polyimide and urea-formaldehyde resin, radiation-cured resin, or combinations thereof. The base layer can consist essentially of only one layer of material or can have a multi-layered structure. For example, the base layer can comprise multiple layers or stacks, with the individual layers of the stack coupled together using a suitable fixing mechanism (e.g., adhesive and / or primer layer). The base layer (or a single layer of the stack) can have any shape and thickness. The thickness of the base layer (i.e., the dimension of the base layer in the directions of the first and second main surfaces) can be less than 10 mm, less than 5 mm, less than 1 mm, less than 0.5 mm, less than 0.25 mm, less than 0.125 mm or less than 0.05 mm.

[0139] In some examples, the abrasive surface 329 can be formed as a two-dimensional abrasive material, such as a conventional abrasive disc, having a layer of abrasive particles fixed to a backing by one or more resin or other adhesive layers. This abrasive disc can then be applied to a rotary tool substrate. Alternatively, the abrasive surface 329 can be formed as a three-dimensional fixed abrasive, such as a resin or other adhesive layer containing abrasive particles dispersed therein. Combinations of abrasive surfaces 329 can include an abrasive compound with a suitable height to allow the abrasive compound to wear down during use and / or dressing, exposing new abrasive particle layers. Abrasive articles can include three-dimensional, textured, flexible, fixed abrasive structures comprising multiple precisely shaped abrasive compounds.

[0140] Precision-formed abrasive compounds can be arranged in arrays to form three-dimensional, textured, flexible, fixed abrasive structures. Suitable arrays include, for example, those described in U.S. Patent No. 5,958,794 (Bruxvoort et al.). Abrasive articles can include patterned abrasive structures. Abrasive articles obtained from 3M Company, St. Paul, Minnesota, under the trade names TRIZACT Patterned Abrasive and TRIZACT Diamond Tile Abrasive, are exemplary patterned abrasives. Patterned abrasive articles comprise precisely aligned monolithic abrasive compounds and manufactured from molds, dies, or other techniques. Such patterned abrasive articles can be ground, polished, or simultaneously ground and polished.

[0141] The shape of each precision-forming abrasive compound can be selected based on specific applications (e.g., workpiece material, working surface shape, contact surface shape, temperature, resin phase material). The shape of each precision-forming abrasive compound can be any useful shape, such as a cube, cylinder, prism, regular parallelepiped, pyramid, truncated pyramid, cone, hemisphere, truncated cone, cross, or columnar section with a distal end. Composite pyramids, for example, can have three, four, five, or six sides.

[0142] In at least some embodiments herein, each precision-formed abrasive compound may be wedge-shaped, having a first triangular face opposite the second triangular face. The wedge-shaped abrasive compound may have one or more quadrilateral faces, such as having four corners and sides. In some embodiments, at least one face is trapezoidal. In some embodiments, at least two faces are trapezoidal. In some embodiments, at least one face is rectangular.

[0143] The cross-sectional shape of the abrasive compound at the base can differ from that at the distal end. The transition between these shapes can be smooth and continuous or stepwise. Precision-formed abrasive compounds can also be mixtures of different shapes. Precision-formed abrasive compounds can be arranged in rows, helices, spirals, or lattice patterns, or they can be randomly placed. Precision-formed abrasive compounds can be arranged in a design intended to guide fluid flow and / or facilitate debris removal. As described above, precision-formed abrasive compounds can also have the same or different orientations as adjacent shaped abrasive compounds in any arrangement described herein.

[0144] One or more sides forming the precision-formed abrasive compound may gradually narrow towards the distal end. The taper angle may range from about 1 degree to less than 90 degrees, for example, from about 1 degree to about 75 degrees, from about 3 degrees to about 35 degrees, or from about 5 degrees to about 15 degrees. The height of each precision-formed abrasive compound is preferably the same, but precision-formed abrasive compounds of different heights may exist in a single article.

[0145] The base of a precision-formed abrasive compound, such as Figures 4A-4C As shown, the bases of adjacent precision-formed abrasive compounds can be adjacent to each other, or they can be separated by a certain distance. In some examples, the physical contact between adjacent abrasive compounds involves a vertical height dimension of no more than 33%, or even 25%, of each contacting precision-formed abrasive compound. This definition of adjacentness also includes an arrangement in which adjacent precision-formed abrasive compounds share a common ground or bridge-like structure that contacts and extends between the opposite sides of the precision-formed abrasive compounds. The abrasives are adjacent because there are no intermediate compounds on a direct imaginary line between the centers of the precision-formed abrasive compounds.

[0146] Precision-formed abrasive compounds can be arranged in a predetermined pattern or at predetermined locations within abrasive articles. For example, when manufacturing abrasive articles by providing an abrasive / resin slurry between a backing and a mold, the predetermined pattern of the precision-formed abrasive compound will correspond to the pattern of the mold. Therefore, the pattern can be repeated from abrasive article to abrasive article.

[0147] A predetermined pattern can be an array or arrangement, meaning the compound is positioned within a designed array, such as aligned rows and columns, or alternating offset rows and columns. In another example, the abrasive compound can be set in a “random” array or pattern. This means the compound is not within the rows and columns of the array described above. However, this “random” array is understood to be a predetermined pattern because the precise positioning of the abrasive compound is predetermined and corresponds to the mold.

[0148] The abrasive material forming the abrasive surface 329 may include polymeric materials, such as resins. In some examples, the resin phase may include curable or curable organic materials. The curing method is not critical and may include, for example, energy curing, such as ultraviolet light or heat. Examples of suitable resin phase materials include, for example, amino resins, alkylated urea-formaldehyde resins, melamine-formaldehyde resins, and alkylated phenylguanidine-formaldehyde resins. Other resin phase materials include, for example, acrylic resins (including acrylates and methacrylates), phenolic resins, polyurethane resins, and epoxy resins. Specific acrylic resins include, for example, ethylene acrylates, acrylic epoxy resins, acrylic polyurethanes, acrylic oils, and acrylic silicone resins. Specific phenolic resins include, for example, resorcinol and phenolic resins, as well as phenolic / latex resins. In the same or different examples, the resin may include one or more epoxy resins, polyester resins, polyvinyl butyral (PVB) resins, acrylic resins, thermoplastic resins, thermosetting resins, ultraviolet-curing resins, and electromagnetic radiation-curing resins. For example, epoxy resin may represent about 20% to about 35% by weight of the abrasive material. In the same or different examples, polyester resin represents 1% to 10% by weight of the abrasive material. The resin may further contain conventional fillers and curing agents, such as those described in U.S. Patent No. 5,958,794 (Bruxvoort et al.), all of which are incorporated herein by reference.

[0149] Examples of abrasive particles suitable for fixed abrasive pads include cubic boron nitride, fused alumina, ceramic alumina, heat-treated alumina, white fused alumina, black silicon carbide, green silicon carbide, titanium diboride, boron carbide, silicon nitride, tungsten carbide, titanium carbide, diamond, cubic boron nitride, cerium oxide, chromium oxide, hexagonal boron nitride, alumina zirconium, iron oxide, cerium oxide, garnet, alumina zirconium, alumina-based sol-gel derived abrasive particles, and mixtures thereof. Alumina abrasive particles may contain metal oxide modifiers. Examples of alumina-based sol-gel derived abrasive particles can be found in U.S. Patent Nos. 4,314,827; 4,623,364; 4,744,802; 4,770,671; and 4,881,951, all of which are incorporated herein by reference. Diamond and cubic boron nitride abrasive particles may be monocrystalline or polycrystalline. Particularly preferred examples are diamond, cubic boron nitride, alumina, and silicon carbide for rough grinding, and silica and alumina for finish grinding. Furthermore, in some embodiments, agglomerates of any of the above-described abrasive particles may be used, such as those described in U.S. Patent 5,039,311, issued August 13, 1991. Other examples of suitable inorganic abrasive particles include silica, iron oxide, chromium oxide, cerium oxide, zirconium oxide, titanium oxide, tin oxide, and γ-alumina.

[0150] In some examples, the abrasive surface 329 may further include a backing layer behind the abrasive composite layer, selectively with an adhesive disposed therebetween. Any type of backing material is considered, including flexible and rigid backings. Examples of flexible backings include, for example, polymer films, primer polymer films, metal foils, cloth, paper, vulcanized fibers, nonwoven fabrics, and their treated versions and combinations thereof. Examples include polymer films of polyester and copolyester, microporous polyester, polyimide, polycarbonate, polyamide, polyvinyl alcohol, polypropylene, polyethylene, etc. When used as a backing, the thickness of the polymer film backing is selected to maintain the desired range of flexibility within the abrasive article.

[0151] Useful backings include, for example, film backings and foam backings.

[0152] Suitable film backings include polymer films and primer polymer films, particularly those used in the abrasive field. Useful polymer films include, for example, polyester films (e.g., ethylene-acrylic acid copolymer primer polyethylene terephthalate), polyolefin films (e.g., polyethylene or polypropylene films), and resilient polyurethane films. The film backing can be a laminate of two polymer films.

[0153] Useful polymer foams include both open-cell and closed-cell polymer foams, which are generally compressible and elastic. Useful polymer foams include elastic foams such as neoprene foam, ethylene / propylene rubber foam, butyl rubber foam, polybutadiene foam, polyisoprene foam, EPDM polymer foam, polyurethane foam, ethylene-vinyl acetate foam, neoprene foam, and styrene / butadiene copolymer foam. Useful foams also include thermoplastic foams such as polyethylene foam, polypropylene foam, polybutene foam, polystyrene foam, polyamide foam, polyester foam, and plasticized polyvinyl chloride (i.e., PVC) foam. Examples of open-cell foams include polyester polyurethane foams with trade names R200U, R400U, R600U, and EF3-700C, available from Illbruck, Minneapolis, Minnesota.

[0154] Useful foam backing is typically between 1 and 15 millimeters thick; however, this is not necessary.

[0155] The backing may have an adhesion interface layer on its back surface to secure the abrasive article to a support pad or spare pad. Half of the attachment system may be, for example, a pressure-sensitive adhesive or tape, a loop fabric for hook and loop attachments, a hook structure for hook and loop attachments, or an engagement attachment system. Further details about such attachment systems can be found, for example, in U.S. Patent Nos. 5,152,917 (Pieper et al.); 5,454,844 (Hibbard et al.); 5,672,097 (Hoopman); 5,681,217 (Hoopman et al.); and U.S. Patent Application Publication Nos. 2003 / 0143938 A1 (Braunschweig et al.) and 2003 / 0022604 A1 (Annen et al.).

[0156] In some examples, the abrasive surface 329 may include one or more additional layers. For example, the abrasive surface may include an adhesive layer, such as a pressure-sensitive adhesive, a hot melt adhesive, or an epoxy resin. A "sub-pad," such as a thermoplastic layer, like a polycarbonate layer, can impart greater stiffness to the pad through global flatness. The sub-pad may also include a layer of elastic compressible material, such as a foam material layer. Sub-pads comprising a combination of thermoplastic and compressible material layers may also be used. Additionally, or optionally, a thin metal film for static elimination or sensor signal monitoring, an optically transparent layer for light transmission, a foam layer for finer finishing of the workpiece, or ribbed material for imparting "hard bands" or rigid regions to the polished surface may be included.

[0157] As those skilled in the art will understand, abrasive surfaces can be formed by a variety of methods, including, for example, molding, extrusion, embossing, and combinations thereof.

[0158] In illustrative examples, abrasive composites may include porous ceramic abrasive composites. Porous ceramic abrasive composites may include individual abrasive particles dispersed within a porous ceramic matrix. The term "ceramic matrix" as used herein includes both glassy and crystalline ceramic materials. These materials generally belong to the same category when considering their atomic structure. Bonding between adjacent atoms is the result of electron transfer or electron sharing. Alternatively, weaker bonds are formed due to the attraction of positive and negative charges, called secondary bonds. Crystalline ceramics, glasses, and glass-ceramics possess both ionic and covalent bonds. Ionic bonds are achieved due to the transfer of electrons from one atom to another. Covalent bonds are formed due to the sharing of valence electrons and are highly directional. In contrast, the dominant bond in metals is called a metallic bond, which involves non-directional electron sharing. Crystalline ceramics can be further subdivided into silicate-based silicates (e.g., refractory clays, mullite, porcelain, and Portland cement), non-silicate oxides (e.g., alumina, magnesia, MgAl₂O₄, and zirconium oxide), and non-oxide ceramics (e.g., carbides, nitrides, and graphite). Glass-ceramics are compositionally similar to crystalline ceramics. Due to specific processing techniques, these materials lack the long-range order of crystalline ceramics. Glass ceramics are the result of controlled heat treatment to produce at least about 30% and up to about 90% crystalline phase or phase.

[0159] In the illustrative examples, at least a portion of the ceramic matrix comprises a glass-ceramic material. In further examples, the ceramic matrix comprises at least 50%, 70%, 75%, 80%, or 90% by weight of glass-ceramic material. In one example, the ceramic matrix is ​​substantially composed of glass-ceramic material. Particularly useful for grinding the edges of cover glass, the ceramic matrix comprises at least 30% by weight of glass-ceramic material.

[0160] In various examples, the ceramic matrix may include glasses comprising metal oxides, such as alumina, boron oxide, silicon oxide, magnesium oxide, sodium oxide, manganese oxide, zinc oxide, and mixtures thereof. The ceramic matrix may include alumina borosilicate glass comprising Si₂O, B₂O₃, and Al₂O₃. Alumina borosilicate glass may comprise approximately 18% B₂O₃, 8.5% Al₂O₃, 2.8% BaO, 1.1% CaO, 2.1% Na₂O, 1.0% Li₂O, with the remainder being Si₂O. Such alumina borosilicate glass is available from Specialty Glass Incorporated in Oldsmar, Florida.

[0161] The term "porous" as used herein describes the structure of a ceramic matrix characterized by the distribution of pores or voids in its mass. Porous ceramic matrices can be formed using techniques well known to those skilled in the art, such as by controlled firing of ceramic matrix precursors or by incorporating pore-forming agents, such as glass bubbles, into the ceramic matrix precursors. Pores can be open to the outer surface of the composite or sealed. Pores in the ceramic matrix are thought to facilitate the controlled decomposition of the ceramic abrasive composite, resulting in the release of used (i.e., passivated) abrasive particles from the composite. Pores can also enhance the properties of the abrasive article (e.g., cutting rate and surface finish) by providing a path for the removal of debris and used abrasive particles at the interface between the abrasive article and the workpiece. Voids (or pore volume) can range from at least 4% by volume, at least 7% by volume, at least 10% by volume, or at least 20% by volume of the composite; less than 95% by volume, less than 90% by volume, less than 80% by volume, or less than 70% by volume of the composite. This is particularly useful for grinding the edges of covered glass, where voids can account for 35% to 65% by weight of the abrasive material.

[0162] In some examples, the abrasive particles may include diamond, cubic boron nitride, fused alumina, ceramic alumina, heat-treated alumina, silicon carbide, boron carbide, zirconium alumina, iron oxide, cerium oxide, garnet, and combinations thereof. In one example, the abrasive particles may include or consist primarily of diamond. Diamond abrasive particles may be natural or synthetically manufactured diamond. Diamond particles may have a distinctly massive or irregular shape. Diamond particles may be monocrystalline or polycrystalline, such as diamonds available under the trade name “Mypolex” from Mypodiamond Inc. in Smithfield, Pennsylvania. Monocrystalline diamonds of various particle sizes are available from Diamond Innovations in Worthington, Ohio. Polycrystalline diamonds are available from Tomei Corporation of America in Cedar Park, Texas. Diamond particles may contain surface coatings, such as metallic coatings (nickel, aluminum, copper, or the like), inorganic coatings (e.g., silicon dioxide), or organic coatings.

[0163] In some examples, the abrasive particles may comprise a mixture of abrasive particles. For instance, diamond abrasive particles may be mixed with a second, softer type of abrasive particle. In this case, the second abrasive particle may have a smaller average particle size than the diamond abrasive particles.

[0164] In the illustrative example, the abrasive particles may be uniformly (or substantially uniformly) distributed within the ceramic matrix. As used herein, “uniformly distributed” means that the unit average abrasive particle density in the first portion of the composite particles does not exceed 20%, 15%, 10%, or 5% compared to any second distinct portion. This contrasts with, for example, abrasive composite particles where the abrasive particles are concentrated on the particle surface.

[0165] In various examples, abrasive composite particles may also include optional additives such as fillers, coupling agents, surfactants, foam inhibitors, etc. The amounts of these materials can be selected to provide the desired properties. Furthermore, abrasive composite particles may include (or adhere to) one or more separating agents on their outer surface. As will be discussed in detail below, one or more separating agents can be used during the manufacture of abrasive composite particles to prevent particle aggregation. Suitable separating agents may include, for example, metal oxides (e.g., alumina), metal nitrides (e.g., silicon nitride), graphite, and combinations thereof.

[0166] In some examples, the abrasive composite particles may have an average size (average principal axis diameter or the longest straight line between two points on two particles) of at least 5 micrometers, at least 10 micrometers, at least 15 micrometers, or at least 20 micrometers; less than 1,000 micrometers, less than 500 micrometers, less than 200 micrometers, or less than 100 micrometers. Abrasive particles particularly useful for grinding the edges of cover glass may have an average particle size of less than about 65 micrometers and a maximum particle size of less than about 500 micrometers.

[0167] In illustrative examples, the average size of the abrasive composite particles is at least about 3 times, at least about 5 times, or at least about 10 times the average size of the abrasive particles used in the composite particles; and less than 30 times, less than 20 times, or less than 10 times the average size of the abrasive particles used in the composite particles. In some embodiments, the abrasive particles may have a Mohs hardness of at least 6, or at least 7, or at least 8, at least 9, or at least 10. However, it is explicitly understood that, for some embodiments, abrasive articles with a Mohs hardness less than 6 may be used.

[0168] In various examples, the weight ratio of the abrasive particles to the weight of the glass-ceramic material in the ceramic matrix of the ceramic abrasive composite particles is at least about 1 / 20, at least about 1 / 10, at least about 1 / 6, at least about 1 / 3, and less than about 30 / 1, less than about 20 / 1, less than about 15 / 1, or less than about 10 / 1.

[0169] In various examples, the ratio of abrasive particle size to agglomerate size may be no greater than 15:1, no greater than 12.5:1, or no greater than 10:1. In some examples, the ratio may also be no less than about 3:1, no less than about 5:1, or even no less than about 7:1. Ceramic abrasive composite particles providing such abrasive-to-agglomerate size ratios may be particularly suitable for grinding the edges of cover glass.

[0170] In various examples, the abrasive composite particles can be sized and shaped relative to the size and shape of the cavity of the abrasive surface 329, such that one or more (at most all) abrasive composite particles can be at least partially placed within the cavity. More specifically, the abrasive composite particles can be sized and shaped relative to the cavity such that one or more (at most all) abrasive composite particles have at least a portion extending beyond the cavity opening when fully received by the cavity. As used herein, "fully received" refers to the deepest position the composite particles may reach within the cavity when a non-destructive compressive force (e.g., a force present during a polishing operation, as described below) is applied. In this way, during a polishing operation, the abrasive composite particles of the polishing solution can be received by the cavity and retained (e.g., by frictional force), thereby acting as an abrasive working surface.

[0171] In various examples, the amount of porous ceramic matrix in the ceramic abrasive composite particles is at least 5, at least 10, at least 15, at least 33, less than 95, less than 90, less than 80, or less than 70% by weight, based on the total weight of the porous ceramic matrix and the individual abrasive particles, wherein the ceramic matrix includes any fillers, adhered separating agents, and / or other additives besides the abrasive particles.

[0172] In various examples, abrasive composite particles can be precisely shaped or irregularly shaped (i.e., non-precisely shaped). Precisely shaped ceramic abrasive composite particles can be of any shape (e.g., cubic, blocky, cylindrical, prismatic, pyramidal, truncated pyramidal, conical, truncated conical, spherical, hemispherical, cruciform, or columnar). Abrasive composite particles can be a mixture of different abrasive composite particle shapes and / or sizes. Alternatively, abrasive composite particles can have the same (or substantially the same) shape and / or size. Non-precisely shaped particles include spheres, which can be formed by, for example, a spray drying process.

[0173] Abrasive composite particles can be formed through any particle-forming process, including, for example, casting, replication, microreplication, molding, spraying, spray drying, atomization, coating, electroplating, deposition, heating, curing, cooling, curing, compression, compaction, extrusion, sintering, brazing, atomization, impregnation, vacuuming, sandblasting, crushing (depending on the choice of matrix material), or any other available method. If the composite particles are initially formed into a large object, it may be necessary to select fragments within a narrow size range using methods well known to those skilled in the art. In some examples, ceramic abrasive composite particles may comprise glass-bonded diamond agglomerates produced using the techniques disclosed in U.S. Patent Nos. 6,551,366 and 6,319,108. This is particularly useful for grinding the edges of covered glass, where the volume ratio of diamond agglomerates in the abrasive to the resin binder is greater than 3:2.

[0174] It is particularly useful for grinding the edges of covered glass, where ceramic abrasive aggregates can account for 35% to 65% of the weight of the abrasive material.

[0175] Typically, methods for manufacturing ceramic abrasive composite particles involve mixing an organic binder, a solvent, abrasive particles (e.g., diamond), and ceramic matrix precursor particles (e.g., glass frit); spray-drying the mixture at high temperatures to produce “green” abrasive / ceramic matrix / binder particles; collecting the “green” abrasive / ceramic matrix / binder particles and mixing them with a separating agent, such as coated white alumina; then annealing the powder mixture at a temperature sufficient to vitrify the ceramic matrix material containing the abrasive particles, while simultaneously removing the binder by combustion; thus forming ceramic abrasive composite particles. The ceramic abrasive composite particles can be selectively sieved to a desired particle size. The separating agent prevents the “green” abrasive / ceramic matrix / binder particles from agglomerating during vitrification. This allows the vitrified ceramic abrasive composite particles to maintain a similar size to the “green” abrasive / ceramic matrix / binder particles formed directly from the spray dryer. Small weight fractions of the separating agent, less than 10%, less than 5%, or even less than 1%, may adhere to the outer surface of the ceramic matrix during vitrification. Separating agents typically have a softening point higher than the softening point of the ceramic matrix (for glass materials, etc.), or a melting point higher than the softening point of the ceramic matrix (for crystalline materials, etc.), or a decomposition temperature higher than the softening point of the ceramic matrix. It is understood that not all materials have a melting point, softening point, or decomposition temperature. For materials with two or more melting points, softening points, or decomposition temperatures, it is understood that the lower of these melting points, softening points, or decomposition temperatures is higher than the softening point of the ceramic matrix. Examples of separating agents include, but are not limited to, metal oxides (e.g., alumina), metal nitrides (e.g., silicon nitride), and graphite.

[0176] In some examples, abrasive composite particles can be surface-modified (e.g., covalent, ionic, or mechanically) with agents that will impart beneficial properties to the abrasive slurry. For example, the surface of glass particles can be etched with acid or base to create a suitable surface pH. Covalently modified surfaces can be created by reacting with one or more surface treatment agents. Examples of suitable surface treatment agents include silanes, titanates, zirconates, organophosphates, and organosulfonates. Examples of silane surface treatment agents suitable for the present invention include octyltriethoxysilane, vinylsilanes (e.g., vinyltrimethoxysilane and vinyltriethoxysilane), tetramethylchlorosilane, methyltrimethoxysilane, methyltriethoxysilane, propyltrimethoxysilane, propyltriethoxysilane, tri-[3-(trimethoxysilyl)propyl]isocyanurate, vinyl-tri-(2-methoxyethoxy)silane, γ-methacryloyloxypropyltrimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, etc. Methoxysilanes, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane, bis-(γ-trimethoxysilylpropyl)amine, N-phenyl-γ-aminopropyltrimethoxysilane, γ-ureidopropyltrialkoxysilane, γ-ureidopropyltrimethoxysilane, acryloyloxyalkyltrimethoxysilane, methacryloxyalkyltrimethoxysilane, phenyltrichlorosilane, phenyltrimethoxysilane, phenyltriethoxysilane, SILQUEST A1230 proprietary nonionic silane dispersant (available from Momentive, Columbus, Ohio), and mixtures thereof. Examples of commercially available surface treatment agents include SILQUEST A174 and SILQUEST A1230 (available from Momentive). Surface treatment agents can be used to adjust the hydrophobic or hydrophilic properties of the surfaces they modify. Vinylsilanes can provide more complex surface modifications by reacting vinyl groups with another reagent. Reactive or inert metals can be combined with glass diamond particles to chemically or physically alter the surface. Sputtering, vacuum evaporation, chemical vapor deposition (CVD), or molten metal techniques can be used.

[0177] As another example, abrasive materials can include metal particles dispersed in resin combined with abrasive composite particles. The metal particles can provide a bearing effect to protect the resin during grinding operations. Such metal particles can include copper particles, tin particles, brass particles, aluminum particles, stainless steel particles, and metal alloys. For example, the metal particles can constitute 5% to 25% of the weight of the abrasive material. In the same or different examples, the metal particles can have an average particle size of 10 micrometers to 250 micrometers, such as 44 micrometers to 149 micrometers, for example, about 100 micrometers. Such examples may be particularly suitable for abrasive materials used for grinding the edges of cover glass.

[0178] Polymethyl methacrylate (PMMA) beads are another optional additive that can be dispersed in the resin of the abrasive material. In such examples, PMMA beads can comprise 1% to 10% by weight of the abrasive material. Such examples may be particularly suitable for abrasive materials used for grinding the edges of cover glass.

[0179] In addition to resins, such as epoxy resins and abrasive composite particles, abrasive materials may include additional additives, such as filler materials or other materials. In some examples, the filler material may include one or more of alumina, nonwoven fibers, silicon carbide, and cerium oxide particles. In such examples, the filler material may constitute 5% to 50% of the weight of the abrasive material. Such examples may be particularly suitable for abrasive materials used for grinding the edges of cover glass.

[0180] In various examples, abrasive materials as described herein can be used to form abrasive surfaces for rotary tools particularly suitable for grinding the edges of cover glass. In some examples, the abrasive material, including resin, abrasive composite particles, and any additional additives dispersed in the resin, can be molded to form an abrasive surface or even the entire rotary tool 328. For example, the abrasive material can be overmolded onto the core of the rotary tool 328 to form an abrasive surface. Typically, such a core will include a tool shank and portions embedded in the abrasive material to mechanically secure the abrasive material to the tool shank.

[0181] In other examples, the abrasive material may be a coating on a substrate. In various examples, the substrate may represent the core of the rotating tool 328, providing the shape of the rotating tool, with the abrasive applied directly to the core of the rotating tool. In other examples, the substrate may represent a sheet material later applied to the core of the rotating tool. In such examples, the substrate may be a planar substrate or a curved substrate. In various examples, the substrate may include one or more of the following: polymer film, nonwoven substrate, fabric substrate, rubber substrate, elastic substrate, foam substrate, compliant material, extruded film, primer substrate, and unprimer substrate.

[0182] In some specific examples, the abrasive material coating can be formed from an abrasive composite layer deposited on a polymer film, with a primer layer between the abrasive composite layer and the polymer film. The polymer film itself can be positioned on a compliant layer, such as foam, and an adhesive can be used to secure the polymer film to the compliant layer. The combined abrasive material coating, polymer material, and compliant material can then be applied to the core of the rotary tool 328 to form the shape of an abrasive surface on the rotary tool 328. In some examples, the abrasive material can be further cured after application to the core of the rotary tool 328.

[0183] Figure 5B and Figure 5D-5HExamples of rotary abrasive tools suitable for grinding glass, such as cover glass, sapphire, ceramics, etc., are shown. Figure 5C The cover glass of the electronic device was displayed. Figure 5B and Figure 5D-5F Each tool may include an abrasive material as described herein and may be used as a rotary tool 328 in system 310.

[0184] in particular, Figure 5B An example rotary abrasive tool 300 is shown. The rotary abrasive tool 300 includes a set of flexible flaps 304 with abrasive outer surfaces 306, 308, which can grind the edges of a workpiece at multiple angles by bending the flexible flaps. The rotary abrasive tool 300 also includes a tool shank 302, defining the axis of rotation of the tool 300. The flexible flaps 304 can be secured to the tool shank 302 by an optional fixing mechanism 305, which can represent a pin, screw, rivet, or other fixing mechanism. The tool shank 302 can be configured to be mounted in the chuck of a rotary machine, such as a drilling rig or a CNC machine tool.

[0185] Flexible flaps 304 form a flexible planar portion located opposite the tool shank 302. Each flexible flap 304 has a first abrasive outer surface 306 formed on a first side, which generally faces away from the tool shank 302. Each flexible flap 304 also has an optional second abrasive outer surface 308 formed on a second side, which generally faces the tool shank 302. An optional substrate 310 is located between the first abrasive outer surface 306 and the second abrasive outer surface 308. In some examples, the substrate 310 may include an elastically compressible layer as a backing for the abrasive outer surfaces 306, 308.

[0186] The rotary abrasive tool 300 also includes a cylindrical portion 314 attached to the tool shank 302. The cylindrical portion 314 forms a third abrasive outer surface 316 surrounding the axis of rotation. The cylindrical portion 314 may also include an optional elastic compressible layer as a backing for the abrasive outer surface 316. A flexible flap 304 extends relative to the axis of rotation beyond the outer diameter of the cylindrical portion 314.

[0187] One or more of the abrasive outer surfaces 306, 308, and 316 may include an abrasive coating as described herein. In the same or different examples, one or more of the abrasive outer surfaces 306, 308, and 316 may include an abrasive film as described herein. Such abrasives may be fixed to a substrate of tool 300, such as substrate 310, using epoxy resin.

[0188] In various examples, as described herein, one or more of the abrasive outer surfaces 306, 308, and 316 may provide an abrasive grain size of less than 20 micrometers, for example, an abrasive grain size between about 10 micrometers and about 1 micrometer, such as an abrasive grain size of about 3 micrometers. Such examples may be particularly suitable for edge grinding of cover glass.

[0189] In some examples, the third abrasive outer surface 316 of the cylindrical portion 314 may include portions with different abrasive grit sizes. In such examples, different portions may be used sequentially to provide improved surface finish or speed during grinding operations, such as edge grinding of a cover glass.

[0190] like Figure 5D-5F The cylindrical portion 314 facilitates grinding the edge between the first and second sides of the workpiece from the tool shank 302 during operation of the tool 300. Furthermore, the flexible flap 304, by bending, facilitates grinding the first corner adjacent to the first side of the workpiece at multiple angles, using the first abrasive outer surface 306 when applied to the first corner of the workpiece. Similarly, the flexible flap 304, by bending, facilitates grinding the second corner adjacent to the second side of the workpiece at multiple angles, using the second abrasive outer surface 308, where the second side of the workpiece is opposite the first side, when applied to the second corner of the workpiece.

[0191] Figure 5C Cover glass 350 is shown; this is the cover glass for electronic devices, such as mobile phones, personal music players, or other electronic devices. In some examples, cover glass 350 can be a component of the touchscreen of an electronic device. Cover glass 350 can be alumina silicate-based glass with a thickness of less than 1 mm, although other compositions may also be possible.

[0192] The cover glass 350 includes a first primary surface 362 and a second primary surface 364 opposite each other. Typically, but not always, the primary surfaces 362 and 364 are planar surfaces. An edge surface 366 extends along the periphery of the primary surfaces 362 and 364, the periphery including a rounded corner 367. The cover glass 350 also forms an aperture 352. The aperture 352 includes its own edge surface.

[0193] To improve crack resistance and appearance, the surfaces of the cover glass 350, including the main surfaces 362 and 364, the edge surface 366, and the edge surface of the hole 352, should be as smooth as possible after the basic shape of the cover glass 350 is formed. After machining to form the basic shape of the cover glass 350, polishing can be performed using, for example, a CeO-based coolant to remove grinding and machining marks from the cover glass 350.

[0194] Furthermore, as described in this article, rotating abrasive tools, such as Figures 5A-5B and Figure 5D-5HThe aforementioned tool can be used to reduce edge surface roughness, such as edge surface 366 and the edge surface of hole 352, after machining cover glass features using a CNC machine tool. The intermediate grinding step can reduce polishing time to provide the required surface finish quality for cover glass 350, not only reducing production time but also providing more precise dimensional control during cover glass 350 production.

[0195] Figure 5D-5H A rotary abrasive tool 100 is shown for grinding a cover glass 350, which may represent a partially finished cover glass as it has not yet been polished or hardened after machining to form its basic shape. The rotary abrasive tool 300 can first be fixed in a rotary tool fixture of a CNC machine tool, such as a rotary machine 323.

[0196] like Figure 5D As shown, the flexible portion surface 306 of the tool 300, and the flexible flap 304, are used to grind the angle between the edge 353 of the hole 352 and the main surface 362. The flexibility of the flexible flap 304 allows the surface 306 to conform to the profile of the angle between the edge 353 of the hole 352 and the main surface 362 as the rotating abrasive tool 300 passes through the hole 352, for example, driven by a CNC machine tool according to a pre-programmed instruction set. In different examples, these angles may be rounded, beveled, or squared before grinding by the tool 300. Similarly, the flexibility of the flexible flap 304 allows the surface 306 to conform to the profile of other angles, including the angle between the edge 366 and the main surface 362, so that these angles can be ground using the surface 306. In different examples, the angle between the edge 366 and the main surface 362 may be rounded, beveled, or squared before grinding by the tool 300.

[0197] The flexible flap 304 is also flexible enough to pass completely through the hole 352, allowing the abrasive outer surface 316 of the cylindrical portion 314 to grind the edge 353 of the hole 352, such as... Figure 5E As shown. Furthermore, the flexibility of the flexible flap 104 allows surface 308 to conform to the profile of the angle between the edge 353 of the hole 352 and the main surface 364 when the rotating abrasive tool 300 is pulled back through the hole 352 by the CNC machine tool. In different examples, these angles may be rounded, beveled, or square before the tool 300 grinds. Similarly, the flexibility of the flexible flap 304 allows surface 306 to conform to the profile of other angles, including the angle between the edge 366 and the main surface 364, so that these angles can be ground using surface 308.

[0198] In this way, tool 300 allows grinding of all surfaces associated with hole 352, including edge 353 and the angle between edge 353 and main surfaces 362, 364. This grinding can be performed by continuously rotating tool 300 while the surfaces associated with hole 352 are in contact with abrasive surfaces 306, 316, and 308. Tool 300 also allows grinding of all surfaces associated with edge 166, including the angle between edge 366 and main surfaces 362, 364. This grinding can be performed by continuously rotating tool 300 while the surfaces associated with edge 366 are in contact with abrasive surfaces 306, 316, and 308. After grinding the surfaces associated with edges 353 and 366 using tool 300, an abrasive slurry or coolant, such as a CeO-based coolant, can be used to further improve surface finish. In the same or different examples using abrasive coolants, tool 300 may be part of two or more tools 100 providing different abrasive grades. For example, tools can be used sequentially, from higher abrasive grades to lower abrasive grades, to improve surface finish.

[0199] Figure 5G Rotary abrasive tool 370 is shown. Rotary abrasive tool 370 is basically similar to rotary abrasive tool 400, except that rotary abrasive tool 370 does not include flexible flap 304.

[0200] The rotary abrasive tool 370 includes a tool shank 372 that defines the axis of rotation of the tool 370. The tool shank 372 can be configured to be mounted in the chuck of a rotary machine, such as a drilling rig or a CNC machine tool. The rotary abrasive tool 370 also includes a cylindrical portion 374 coaxially aligned with and attached to the tool shank 372. The cylindrical portion 374 forms an abrasive outer surface 376 having a circular cross-section perpendicular to the axis of rotation of the tool 370. In some examples, different portions of the abrasive outer surface 376 may include two or more different abrasive grit sizes. The abrasive outer surface 376 may include an abrasive coating as described herein. In the same or different examples, the abrasive outer surface 376 may include an abrasive film as described herein.

[0201] After grinding the workpiece surface using tool 370, an abrasive slurry coolant, such as a CeO-based coolant, can be used to further improve the surface finish. In the same or different examples using abrasive slurry or coolant, tool 370 may be part of two or more tools 370 providing different abrasive grades. For example, tools can be used sequentially from higher abrasive grades to lower abrasive grades to improve the surface finish.

[0202] Figure 5HA rotary tool 380 is shown, in which an abrasive outer surface 376 is wrapped around the edge of a cylindrical portion, such that a portion 386 is located at the end of the shank, while a portion 382 is located on the side of the shank. This results in a precisely shaped abrasive compound having different orientations on the surface of the tool 380.

[0203] Figures 6A-6D A rotation tool according to an embodiment of this document is shown. Rotation tool 400 may be similar to rotation tools 300 and 370. Figure 6A A side view of a rotary tool with an abrasive layer is shown. Figure 6B An exploded view 410 of a rotary tool 400 is shown. An abrasive layer 406 is coupled to a compliant layer 404 via an adhesive or other means, and the compliant layer 404 is in turn coupled to a shaft 402. The shaft 402 may be made of metal. The compliant layer 404 may be made of any suitable compliant material and may have a thickness suitable for a given grinding operation. The abrasive layer 406 comprises a precisely shaped abrasive compound arranged in a precise grid pattern as described in the embodiments herein on the surface of the rotary tool 400. Figure 6C A cross-sectional view of the rotation tool 400 is shown, demonstrating the compressibility of the compliant layer 404.

[0204] Figure 6D A schematic cross-sectional view 420 of a rotary tool 400 is shown. A precisely shaped abrasive compound 406, such as... Figure 6D As shown, they can be positioned such that adjacent compounds have at least some contact along their edges. However, it is explicitly considered that there may be at least some space between adjacent precision-formed abrasive compounds. As shown, in some embodiments, the precision-formed abrasive compound is wedge-shaped, having a first triangular face opposite to the second triangular face (in... Figure 6D (As shown in the image). A quadrilateral face can connect to the opposite triangular face and can interface with the abrasive backing 422.

[0205] The precision-formed abrasive compound 406 comprises a plurality of abrasive particles in a resin binder, as described herein. In some embodiments, the abrasive particles comprise diamond particles, and the binder comprises acrylate.

[0206] In some embodiments, the precisely shaped abrasive composite 406 is formed as a single structure with the abrasive layer 422. However, it is explicitly considered that in some embodiments, the abrasive layer 422 may have a different composition. For example, the abrasive layer 422 may be made of a binder material without abrasive particles to save costs.

[0207] In some embodiments, the abrasive layer 422 is coupled to a polymer film backing. The abrasive layer 422 can be coupled to the compliant layer 426 via an adhesive 424. The compliant layer 426 can be made of any suitable resilient compressible material. For example, rubber or foam is used in some embodiments. The compliant layer 426 can be at least 1 mm thick, or in some embodiments, at least 2 mm thick, or at least 3 mm thick. In some embodiments, the compliant layer 426 is less than 10 mm thick, or less than 8 mm thick, or less than 6 mm thick, or less than 5 mm thick, or even less than 4 mm thick.

[0208] Tool 400 may have a metal body 428 made of any suitable metal.

[0209] Figures 7A-7D The shape of the composite abrasive structure is shown in more detail in the example.

[0210] Figures 8A-8F Different deformable abrasive film patterns that can be used in rotary tools according to the embodiments herein are shown.

[0211] In some embodiments, the structured abrasive article is a compliant abrasive film having a structured abrasive layer coupled to the compliant layer, with or without an adhesive, for example. Figures 8A-8F In the embodiments described, the structured abrasive article is converted into a shape that can be applied to the tool. For 3D contour shape polishing applications, the structured abrasive article is converted into a shape that can wrap around the edge of the tool body.

[0212] Manufacturers of glass-working equipment, such as mobile phone manufacturers, are increasingly upgrading glass materials to include ceramic glass, which in turn increases the demand for abrasive articles with higher cutting power and longer service life. This material may contain at least some amorphous phases and some crystalline phases. The embodiments described herein may be particularly suitable for grinding ceramic glass, available for example under the trade names NEOCERAM™ or Robax™. Ceramic glass can withstand higher temperatures and is shatter-resistant.

[0213] Figures 8A-8C A petal-shaped pattern for conforming to the abrasive film pattern is shown. The petal-shaped pattern is then wrapped around a cylindrical tool such that the edge of each petal contacts or nearly contacts the circular face of the tool, rather than on the circular face of the tool.

[0214] Figure 8A A schematic diagram 500 shows a petal pattern 502, including multiple petals 504 arranged around a central hole 506. (See diagram 500.) Figure 8BAs shown, a petal pattern is applied to a cylindrical rotary tool, aligning the central hole 506 with the shaft receiving portion of the tool body. The petal pattern 502 can be simply understood as an annular portion 516 contacting the circular surface of the rotary tool 512, and multiple petal portions 518 wrapping around the corners 512 of the tool body, such that a portion of each petal portion 518 contacts the curved side. In the illustrated embodiment, a large portion of the surface area of ​​each petal portion 518 contacts the curved side. In the illustrated embodiment, the entire annular portion 516 contacts the circular surface.

[0215] like Figure 8C As shown, adjacent petals do not fully contact each other along the edge, leaving a gap of 522. Figure 8C As shown in the image, the gaps can be filled with adhesive to increase adhesion.

[0216] In some embodiments, the tools described herein are used with a coolant, which can also affect the tool's functionality. For example, when used with cerium oxide coolant, Figures 8A-8C The tool design shown exhibits a compliant abrasive film peeling off from the tool body, typically due to the petals loosening from the tool body, as coolant may cause deterioration of the adhesive 524.

[0217] A new pattern is needed that can provide the required grinding capability and appropriate service life. Figure 8D An example embodiment is shown, in which pattern 600 has a rectangular base 612 and a plurality of triangular portions 614 extending from the base. However, although Figure 8D The diagram shows triangular portion 614, but explicitly considers that other shapes might be suitable, such as truncated triangles (e.g., trapezoids). Figure 8D As shown, pattern 600 includes a slit extending from the triangle width 610 to the base 608, such that portion 614 can also be described as a pentagon. Furthermore, a circular polygonal shape may also be suitable in some embodiments. Other shapes may also be suitable. Figure 8D An embodiment is shown in which triangle 614 is an isosceles triangle with a height 608 greater than the width 610. In some embodiments, the height 608 is at least 1.5 times the width 610, or even at least 2 times the width 610, or at least 2.5 times the width 610.

[0218] The base 612 may have a height 606 that is less than the height 608 of the triangular portion. In some embodiments, the height 608 of the triangular portion is at least 1.5 times the height 606, or at least 2 times the height 606, or even at least 2.5 times the height 606, or even at least 3 times the height 606, or even greater.

[0219] Pattern 600 can be defined by base length 602 and height 604, which can be represented as a combination of height 606 and height 608, for example.

[0220] Figure 8E A rotary abrasive tool is shown, wherein an compliant abrasive film 622 with pattern 600 is coupled to a rotary tool 620. The film 622 is wrapped around the curved side and the circular edge 624 connecting the cylindrical tool body. Triangular portions of the film 622 are also wrapped around the edge 626, such that they extend into the central hole of the rotary abrasive tool body.

[0221] In some embodiments, the triangular portions of the membrane 622 extend across the edge 624, such that a first portion of each triangular portion covers the curved side of the tool 620, and a second portion covers the circular surface.

[0222] In some embodiments, the rectangular body portion 612 is coupled to the curved side of the tool 620 and does not cross the edge 624.

[0223] Figure 8F A method 630 for manufacturing a rotary tool for 3D abrasive operations according to embodiments herein is illustrated. For example... Figure 8F As shown, a compliant abrasive film is wrapped around the tool body, such that the body portion 612 is coupled to the curved side of the cylindrical tool, and the triangular portion 614 is folded so that the circular surface of the tool is covered. In some embodiments, the triangular portion 614 may be further folded into the central hole when the tool body is rotated to receive a shaft. This may increase the durability of the compliant abrasive film and reduce the peeling of the triangular portion from the tool body.

[0224] Figure 8D-8F The compliant abrasive film pattern described in the text may be more... Figures 8A-8C The pattern provides a longer lifespan. According to Figures 8A-8C The tools manufactured using the structure shown, for example, have a lifespan of approximately 40 to 60 parts. According to... Figure 8D-8F The tooling for manufacturing the structure shown can, in some embodiments, have a lifespan of more than 60 parts, or even more than 70 parts, or even more than 80 parts.

[0225] In addition, due to Figure 8D The pattern can be cut from a rectangular shape, rather than Figure 8A The petal pattern has a circular outline, thus resulting in less waste when manufacturing compliant abrasive films for rotating abrasive films used in 3D abrasive operations.

[0226] Figure 9 A method for forming a rotating abrasive tool for 3D abrasive operations according to embodiments herein is illustrated. Method 900 may facilitate the formation of, for example... Figures 8A-8F The rotary tool shown, or other suitable rotary abrasive tool. Tools manufactured according to method 900 may be particularly suitable for 3D abrasive applications—such as grinding on multiple surfaces (e.g., simultaneously on two edges), or grinding on surfaces with 3D geometry (e.g., curved surfaces).

[0227] In step 910, a composite abrasive structure is formed. In embodiments herein, the composite abrasive structure comprises multiple precisely shaped abrasive compounds arranged in a repeating pattern. The abrasive compounds may have, for example, Figures 3A-3H The shapes shown are in some embodiments. However, other shapes may also be suitable. The abrasive compound can be made as follows: Figures 4A-4E The pattern arrangement shown is in some embodiments. However, other arrangements may also be suitable. The composite abrasive structure can be formed or coupled on a thin film backing.

[0228] In step 920, a compliant layer is applied to the tool. In some embodiments herein, the compliant layer comprises a thick rubber layer applied to the tool body and then coupled to a composite abrasive structure. The compliant backing may include at least one compliant layer, such as foam, rubber, or other material that deforms under pressure but is also elastic and at least partially recovers its deformation upon removal of the applied pressure.

[0229] In some embodiments, the compliant layer comprises a foam, which can be any suitable open-cell or closed-cell foam as described herein. In some embodiments, the foam is a polymer foam.

[0230] In step 930, the composite abrasive structure is cut into the desired pattern. Patterning may include cutting, stamping, or otherwise creating a pattern conforming to the abrasive film, such that the two-dimensional film can be wrapped around the three-dimensional structure. Broadly speaking, the pattern includes a base and a plurality of protrusions. The base of the pattern is configured to couple to a first tool body surface along most of its surface. The protrusions are configured to couple to a second tool body surface. In some embodiments, the protrusions are further configured to wrap around at least one edge of the tool body surface. In some embodiments, the protrusions are configured to wrap around at least two edges of the tool body surface.

[0231] A protrusion can generally be described as having a first width at its base and a second width at its end opposite the base coupling end. The second width can be substantially zero, for example, making the protrusion triangular in shape and tapering to a point. However, it is explicitly considered that other shapes may be suitable. The second width should be smaller than the first width. In some embodiments, the protrusions are shaped such that when they wrap around the first and / or second edges of the rotating tool body, adjacent protrusions contact along adjacent protrusion edges to form a continuous surface.

[0232] In step 940, the compliant abrasive film is coupled to the tool body. In some embodiments, the compliant abrasive film is coupled to at least two surfaces of the tool body. For example, the compliant abrasive film may at least partially cover a curved side surface of the cylindrical tool body and at least partially cover a circular surface. In some embodiments, the compliant abrasive film is configured to cover a first edge where the curved side surface and the circular surface intersect, as well as a second edge, such that the compliant abrasive film wraps around the shaft or central bore of the cylindrical tool body.

[0233] Figure 10 A method for grinding a work surface using a 3D rotating abrasive tool is demonstrated, according to embodiments herein. Method 1000 may be particularly useful for grinding hard glass surfaces using coolant.

[0234] In step 1010, the coolant is applied to the working surface. The embodiments described herein may be particularly suitable for grinding hard glass surfaces in conjunction with cerium oxide-based coolants. However, it is explicitly considered that the embodiments described herein may be useful in other applications and / or used in combination with other coolants.

[0235] In step 1020, the working surface contacts the rotary tool. In some embodiments herein, the rotary tool includes a cylindrical tool body with a curved side surface coupled to a circular facet on an edge. The circular facet may have a hole or shaft receiving feature. The rotary tool includes a compliant abrasive film attached to the cylinder. The compliant abrasive film wraps around the edge such that a first portion contacts the curved side surface and a second portion contacts the circular facet. In some embodiments herein, the compliant abrasive film wraps around a second edge formed by the circular facet and the hole.

[0236] The compliant abrasive film, as described in the embodiments herein, includes a composite abrasive structure formed from a plurality of shape-abrasive composites in a repeating pattern. The shape-abrasive composites can be as follows: Figures 3A-3H The shapes shown are in some embodiments. Other suitable shapes are also possible in some embodiments. The shaped abrasive compound can be configured as follows: Figures 4A-4E The pattern arrangement shown is in some embodiments.

[0237] In step 1030, the rotating tool moves relative to the working surface. In some embodiments, the rotating tool remains in a fixed position while the working surface moves. In some embodiments, the working surface remains in a fixed position while the rotating tool moves. In some embodiments, both the rotating tool and the working surface move during the abrasive operation. The rotating tool may move linearly along the working surface, in addition to rotation, in some embodiments herein. The rotating tool may move in a track or random track pattern, in some embodiments herein. The rotating tool may also move relative to the working surface in other patterns according to embodiments herein.

[0238] In typical use, according to the structured abrasive article of this disclosure, the abrasive layer comes into frictional contact with the surface of the workpiece, and then at least one of the structured abrasive article or the workpiece moves relative to the other to grind at least a portion of the workpiece.

[0239] Structured abrasive articles can be moved relative to a workpiece manually or mechanically, such as by an electric or pneumatic motor using any method known in the abrasive field. Structured abrasive articles can be detachably attached to a spare pad (e.g., as is the usual practice with discs), or they can be moved without a spare pad (e.g., in the case of abrasive belts).

[0240] A rotary abrasive tool is provided, comprising a cylindrical tool body having a curved side surface and a circular facet. A compliant abrasive film is wrapped around an edge connecting the curved side surface and the circular facet. The compliant abrasive film includes a base attached to the curved side surface and a plurality of protrusions extending from the base. Each protrusion has a first width at the base and a second width at an opposite end, the second width being less than the first width. A structured abrasive layer is disposed on the compliant abrasive film, comprising a plurality of precisely shaped abrasive compounds arranged in a repeating pattern. Each precisely shaped abrasive compound includes a first facet that is substantially triangular, opposite a second facet that is substantially triangular, a quadrilateral surface connected to the first and second triangular faces, a cutting edge formed along one side of the quadrilateral surface, and a contact edge formed along the opposite side, the contact edge being longer than the cutting edge. The precisely shaped abrasive compounds may include ceramic abrasive particles in a binder material.

[0241] A rotating abrasive tool may include a hole in a circular face, the hole having a second edge. A protrusion may be configured to wrap around the second edge and extend into the central hole.

[0242] The protrusion may have a first width at the base end and a second width at the second end opposite to the base end, the second width being smaller than the first width.

[0243] The second width of the protrusion can be essentially zero.

[0244] The protrusions can be configured such that, when wrapped around the second edge, adjacent protrusions contact each other along the protrusion edge.

[0245] Rotary abrasive tools may also include an adhesive layer that couples an compliant abrasive film to the cylindrical tool body.

[0246] A protrusion can have a height greater than its width.

[0247] The protrusion can have a height that is at least twice the width of the protrusion.

[0248] The base and multiple protrusions can form a pattern defined by a hypothetical rectangle.

[0249] The height of the protrusion can be greater than the height of the base.

[0250] The base can be basically rectangular in shape.

[0251] The height of the protrusion can be at least twice the height of the base.

[0252] The structured abrasive layer may include diamond abrasive particles.

[0253] Precision-formed abrasive compounds can be arranged in a grid pattern on a conforming abrasive film.

[0254] Adjacent, precisely shaped abrasive compounds can have different orientations.

[0255] Adjacent, precisely shaped abrasive compounds can have the same orientation.

[0256] A compliant abrasive film may include a compliant backing layer.

[0257] Adhesives may include resins.

[0258] Precision-formed abrasive compounds can be precisely positioned such that the spacing between the first precision-formed abrasive compound and the adjacent second precision-formed abrasive compound is substantially the same as the spacing between the second precision-formed abrasive compound and the adjacent third precision-formed abrasive compound.

[0259] The spacing can be essentially zero, such that the first precisely shaped abrasive particle contacts the second precisely shaped abrasive particle along at least a portion of its edge.

[0260] The face of the first basic triangle can include an obtuse triangle.

[0261] The face of the first basic triangle can include an acute triangle.

[0262] Abrasive particles can have a Mohs hardness of at least 8.

[0263] Precision-formed abrasive compounds can have an aspect ratio of less than 3 for length and thickness.

[0264] The cutting edge can have an uneven cutting profile.

[0265] An uneven cutting profile can include multiple peaks and valleys.

[0266] A method for grinding a work surface using a rotary abrasive tool is provided, the method comprising: applying a coolant to the work surface; frictionally contacting the work surface with the rotary tool, the rotary tool comprising: a cylindrical tool body having a curved side surface and a circular facet having a central hole; a compliant abrasive film wrapped around an edge connecting the curved side surface and the circular facet, the compliant abrasive film comprising: a base attached to the curved side surface; a plurality of protrusions extending from the base, each protrusion having a first width at the base and a second width at an opposite end, the second width being less than the first width; the protrusions being configured to wrap around the edge and enter the central hole; a structured abrasive layer disposed on the compliant abrasive film, the structured abrasive layer comprising a plurality of precisely shaped abrasive compounds arranged in a repeating pattern; and moving the rotary tool relative to the work surface to grind at least a portion of the work surface.

[0267] The compliant backing of a compliant abrasive film may include a polymer foam layer.

[0268] The adhesive layer used to fix the compliant abrasive film to the tool body can be a pressure-sensitive adhesive.

[0269] The abrasive composite in the composite abrasive structure may include diamond abrasive particles in a resin binder.

[0270] The coolant applied to the working surface can be a cerium oxide-based coolant.

[0271] During abrasive operation, the rotary tool can move relative to the working surface in a track pattern.

[0272] Each abrasive compound may have a trapezoidal surface connected to the first and second basic triangular faces.

[0273] The quadrilateral surface of each abrasive compound can be rectangular.

[0274] The first basic triangular facet of each abrasive compound can be an isosceles triangle.

[0275] The first basic triangular facet of each abrasive compound can be an acute triangle.

[0276] The cutting edge of each abrasive compound can be configured to contact the working surface at a rake angle of 80° to 100°.

[0277] A method for forming a rotary abrasive tool for 3D abrasive operations is provided, the method comprising: providing a composite abrasive structure including a plurality of precisely shaped abrasive composites, each composite having a first triangular face opposite to a second triangular face, and a quadrilateral surface connected to the first and second triangular faces; applying the composite abrasive structure to a compliant backing to form a compliant abrasive film; shaping the compliant abrasive film into a pattern including a base and a plurality of protrusions extending from the base, each protrusion having a first width at the base and a second width at an opposite end, the second width being less than the first width; coupling the compliant abrasive film to a cylindrical tool body such that: the base is coupled to a curved side of the tool body; the protrusions wrap around an edge connecting the curved side and a circular face of the tool body and extend to a central hole in the tool body; and securing the compliant abrasive film to the tool body using an adhesive layer; wherein the structured abrasive layer comprises abrasive particles in an adhesive material.

[0278] The composite abrasive structure may include multiple precisely shaped abrasive composites, each composite having a first triangular face opposite to the second triangular face, and a quadrilateral surface connected to the first and second triangular faces.

[0279] The quadrilateral surface of each precision-formed abrasive compound can be rectangular.

[0280] The first basic triangular facet of each precision-formed abrasive compound can be an isosceles triangle.

[0281] The first basic triangular facet of each precision-formed abrasive compound can be an acute triangle.

[0282] Structured abrasive layers may include abrasive particles in the bonding material.

[0283] A structured abrasive article is provided, comprising: a substrate; a backing coupled to the substrate, the backing having first and second opposing principal surfaces, wherein the backing includes a conforming material; a structured abrasive layer disposed on and fixed to the first principal surface, the structured abrasive layer comprising a precisely shaped abrasive compound, wherein the precisely shaped abrasive compound comprises: a first triangular facet opposing a second triangular facet; a quadrilateral surface connected to the first and second triangular faces and forming an angle with the backing; wherein a cutting edge is formed along one side of the quadrilateral, and a contact edge is formed along the opposite side of the quadrilateral, the contact edge being configured to couple to the backing and having a length greater than the cutting edge; wherein the precisely shaped abrasive compound comprises abrasive particles in a binder material.

[0284] Precision-formed abrasive compounds can be precisely positioned such that the spacing between the first precision-formed abrasive compound and the adjacent second precision-formed abrasive compound is substantially the same as the spacing between the second precision-formed abrasive compound and the adjacent third precision-formed abrasive compound.

[0285] The spacing can be essentially zero, such that the first precisely shaped abrasive particle contacts the second precisely shaped abrasive particle along at least a portion of its edge.

[0286] The face of the first basic triangle can include a right triangle.

[0287] The face of the first basic triangle can include an obtuse triangle.

[0288] The face of the first basic triangle can include an acute triangle.

[0289] Adhesive materials may include polymer materials.

[0290] The bonding material may include thermosetting polymer materials.

[0291] Abrasive particles can include diamond.

[0292] Abrasive particles can include ceramic abrasive particles.

[0293] Abrasive particles can have a Mohs hardness of at least 8.

[0294] Precision-formed abrasive compounds can have an aspect ratio of less than 3 for length and thickness.

[0295] Precision-formed abrasive compounds can have an aspect ratio of less than 2 (length to thickness).

[0296] Structured abrasive articles may also include a pressure-sensitive adhesive layer disposed on a second primary surface.

[0297] The cutting edge can have an uneven cutting profile.

[0298] An uneven cutting profile can include multiple peaks and valleys.

[0299] A method for grinding a glass workpiece is provided, the method comprising: frictional contact with at least a portion of a structured abrasive layer of a structured abrasive article on the surface of the glass workpiece; moving the workpiece or at least one of the structured abrasive layers relative to the other to grind at least a portion of the workpiece surface.

[0300] An abrasive rotary tool is provided, comprising: a tool shank defining a rotation axis of the rotary tool; a cylindrical portion attached to the tool shank, wherein the cylindrical portion includes an abrasive outer surface surrounding the rotation axis of the rotary tool; wherein the cylindrical portion facilitates grinding an edge between a first side and a second side of a workpiece when the abrasive rotary tool is operated from the tool shank; wherein the abrasive outer surface includes a structured abrasive layer comprising a plurality of precisely shaped abrasive compounds precisely patterned on the abrasive outer surface, wherein each of the plurality of precisely shaped abrasive compounds includes a first triangular face opposite a second triangular face, and a trapezoidal face connected along a first edge to the first triangular face and along a second edge to the second triangular face, wherein a third edge of each precisely shaped abrasive compound is coupled to a backing and opposite a fourth edge configured to contact the workpiece.

[0301] Multiple precisely shaped abrasive compounds may each include multiple abrasive particles in a binder.

[0302] Multiple abrasive particles can include diamond particles.

[0303] The faces of the first basic triangle can be right triangles.

[0304] The face of the first basic triangle can be an acute triangle.

[0305] The face of the first basic triangle can be an obtuse triangle.

[0306] The fourth edge can be shorter than the third edge.

[0307] The fourth edge can be at least half the length of the third edge.

[0308] The aspect ratio of the thickness to length of a precisely shaped abrasive compound can be less than 3.

[0309] The aspect ratio of the thickness to length of a precisely shaped abrasive compound can be less than 2.

[0310] The abrasive rotary tool may further include: a flexible planar portion located opposite the tool shank; wherein the flexible planar portion forms a second abrasive outer surface on a first side of the flexible planar portion, the first side of the flexible planar portion generally facing away from the tool shank; wherein the flexible planar portion forms a third abrasive outer surface on a second side of the flexible planar portion, the second side of the flexible planar portion generally facing the tool shank; wherein the flexible planar portion facilitates grinding a first corner adjacent to the first side of the workpiece at multiple angles by bending the flexible planar portion, using the second abrasive outer surface when the second abrasive outer surface is applied to the first corner of the workpiece; wherein the flexible planar portion facilitates grinding a second corner adjacent to the second side of the workpiece at multiple angles by bending the flexible planar portion, the second side of the workpiece being opposite to the first side, when the second abrasive outer surface is applied to the second corner of the workpiece; wherein the flexible planar portion extends beyond the outer diameter of the cylindrical portion relative to the rotation axis of the rotary tool.

[0311] Abrasive rotary tools can be configured to perform surface finishing on heat-sensitive metals.

[0312] Abrasive rotary tools can be configured to perform surface finishing on hard or brittle materials.

[0313] Abrasive rotary tools can be configured to perform surface finishing on materials selected from the group consisting of: glass; titanium alloys; sapphire; and ceramics.

[0314] Precision-formed abrasive compounds can include diamond aggregates.

[0315] The volume ratio of diamond agglomerates to resin binder in abrasives can be greater than 3:2.

[0316] Precision-formed abrasive composites may include: a resin; a plurality of ceramic abrasive agglomerates dispersed in the resin, the ceramic abrasive agglomerates comprising individual abrasive particles dispersed in a porous ceramic matrix, wherein at least a portion of the porous ceramic matrix comprises a glass-ceramic material; and metal particles dispersed in the resin.

[0317] A component may include a CNC machine tool, comprising a computer-controlled rotary tool fixture and a workpiece platform. A workpiece represents a partially completed electronic device cover glass, fixed to the workpiece platform, the cover glass forming at least one hole; and an abrasive rotary tool according to any claim.

[0318] A method for grinding the surface of a cover glass hole in an electronic device, comprising: fixing an abrasive rotary tool according to any claim in a rotary tool fixture of a CNC machine tool; and operating the CNC machine tool to grind the surface of the cover glass hole fixed to the CNC machine tool workpiece platform.

[0319] The purposes and advantages of this disclosure are further illustrated by the following non-limiting examples, but the specific materials and quantities described in these examples, as well as other conditions and details, should not be construed as unduly limiting this disclosure. Specific Implementation

[0320] Test methods and preparation procedures

[0321] Test method for the effect of glass abrasive

[0322] A partially finished cover glass is provided, with its peripheral edges formed after a scribing operation. The edges of the partially finished cover glass are then ground using a CNC machine tool to achieve the desired dimensions and shape. After the grinding step, the edges are ready for an abrasive test.

[0323] An abrasive tool assembly was prepared from a structured abrasive sample for evaluation. Figure 6A The tool dimensions were standardized to a diameter of 32.5 mm and a height of 25 mm, featuring a 25 mm diameter machining aluminum core, shank, and body, along with a 3 mm thick foam rubber conformal layer, adhesive layer, and an abrasive sample on the exterior of the assembly. The total thickness of the abrasive and adhesive was 0.75 mm. Rotation speed, load, and coolant flow rate were checked prior to testing.

[0324] The testing machine vertically fixes the abrasive tool assembly in a rotating chuck. A glass plate is placed horizontally on a sliding bearing, with its edge contacting the outer surface of the tool assembly. A constant load is applied between the glass edge and the tool assembly as it rotates. A countdown timer is set to a predetermined time. The rotational speed of the tool assembly is set before it makes contact with the target surface.

[0325] The cutting fluid is a 5% solution of Sabrelube 9016 added to water and then added to the circulation system of the testing machine.

[0326] Abrasive performance testing methods

[0327] The abrasive effect test measures the amount of cover glass removed from the edge of the cover glass under a set force, rotation speed, and time. The controlled force eliminates any test variations due to abrasive wear or changes in the glass components. The glass is contacted with the rotating abrasive at a target rotation speed of 3000 RPM. The test cycle is set to 2 minutes, with multiple cycles performed at the same location on the abrasive. Each 2-minute test uses a new location on the glass edge. At the end of the test, the surface roughness of the location after glass removal is measured.

[0328] Cutting rate test method

[0329] Weigh the cover glass and then secure it to the moving platform. The tool assembly rotates at the set speed, the coolant is turned on, force control is applied to the moving platform, a timer is set, and the glass is moved to contact the tool assembly. After the cycle is complete, turn off the speed and coolant. Remove the glass, dry it, and reweigh it. Record the amount of glass removed. Position the tool in the new position on the cover glass and run the next cycle. Repeat this sequence until the total number of cycles is reached.

[0330] Surface Finishing Test Methods

[0331] Surface finish was measured using an interferometer. The finish produced by the above test method was measured at 20x magnification at the vertex of the cutting rate test location. The average roughness Sa and peak-valley Sz values ​​were recorded.

[0332] Example construction of structured abrasive

[0333] All tool components used in the abrasive performance tests were prepared in the same manner, except for the physical shape of the structured abrasive mounted on the outside of the tool components. All example and comparative example structured abrasive compounds were made from the same constituent materials as the commercial abrasive compound supplied by 3M, product number 678XA-TD3V.

[0334] Example 1 uses Figure 7A The structured abrasive layer is formed by a composite design of abrasive particles with the shape shown. The approximate dimensions of the particles are 927 micrometers in length, 635 micrometers in height, 678 micrometers in cutting edge length, and 902 micrometers in base edge length. The angle 210 is 90 degrees, perpendicular to the base film.

[0335] Comparison Example 1 using Figure 7B The structured abrasive layer of the abrasive particle composite shown in the figure is commercially available as product number 678XA-TD3V.

[0336] Comparison Example 2 using Figure 7C The structured abrasive layer of the abrasive particle composite shown in the figure is commercially available as product number 678XA-TD2A.

[0337] Comparative Example 3 uses a structured abrasive layer formed using a shaped abrasive particle composite as described in U.S. Patent 8,425,278, issued April 23, 2013.

[0338] Figure 11A This is the cutting value of the glass part's weight loss measured at 2-minute intervals using the 3M test method. This shows the removal rate at the same location of the tool over 30 minutes at 2-minute intervals.

[0339] Figure 11B The average roughness Sa is similar across all examples. Figure 11C The peak-valley roughness Sz is similar in all examples. Generally, a higher cutting rate produces a rougher finish, but in this case... Figure 7A The higher cutting rate in the example resulted in a finishing process similar to that in other examples.

[0340] All patents and publications mentioned herein are incorporated herein by reference in their entirety. Various unforeseen modifications and alterations may be made to this disclosure by those skilled in the art without departing from its scope and spirit, and it should be understood that this disclosure should not be unduly limited to the illustrative embodiments described herein.

Claims

1. A grinding rotary tool, the grinding rotary tool comprising: A cylindrical tool body, the cylindrical tool body having a curved side surface and a circular surface; A conformal abrasive membrane, the conformal abrasive membrane being wrapped around the edge of the curved side surface to the circular surface, the conformal abrasive membrane comprising: A base portion, which is connected to the curved side surface; A plurality of protrusions extending from the base portion, each protrusion having a first width at the base portion and a second width at opposite ends, wherein the second width is less than the first width; A structured abrasive layer disposed on the conformal abrasive film, the structured abrasive layer comprising a plurality of precisely shaped abrasive compounds arranged in a repeating pattern, each precisely shaped abrasive compound comprising: The face of the first essentially triangular shape that is opposite to the face of the second essentially triangular shape; A quadrilateral-shaped surface that connects to both the first substantially triangular face and the second substantially triangular face; A cutting edge formed along one side of the surface of the quadrilateral shape, and a contact edge formed along the opposite side, the contact edge being longer than the cutting edge; The precision-formed abrasive composite comprises ceramic abrasive particles in a binder material.

2. The rotary grinding tool of claim 1, wherein the edge is a first edge, wherein the rotating body further includes an orifice in the circular surface having a second edge, and wherein the protrusion is configured to wrap around the second edge and extend into the central orifice.

3. The rotary grinding tool according to claim 1 or 2, wherein the protrusion has a first width at a base end and a second width at a second end opposite to the base end, and wherein the second width is smaller than the first width.

4. The rotary grinding tool according to claim 3, wherein the second width is substantially zero.

5. The rotary grinding tool of claim 2, wherein the protrusion is configured such that when wrapped around the second edge, adjacent protrusions contact each other along the edge of the protrusion.

6. The rotary polishing tool according to any one of claims 1 to 5, further comprising an adhesive layer that binds the conformable polishing film to the cylindrical tool body.

7. The rotary grinding tool according to any one of claims 1 to 6, wherein the protrusion has a protrusion height greater than the protrusion width.

8. The rotary grinding tool according to claim 7, wherein the protrusion has a height that is at least twice the width of the protrusion.

9. The rotary grinding tool of claim 7, wherein the base portion and the plurality of protrusions form a pattern defined by an imaginary rectangle.

10. The rotary grinding tool according to any one of claims 1 to 9, wherein the height of the protrusion is greater than the height of the base portion.

11. The rotary grinding tool of claim 10, wherein the base portion is substantially rectangular in shape.

12. The rotary grinding tool of claim 10, wherein the height of the protrusion is at least twice the height of the base portion.

13. The rotary grinding tool according to any one of claims 1 to 2, wherein the structured abrasive layer comprises diamond abrasive particles.

14. The rotary abrasive tool according to any one of claims 1 to 3, wherein the precisely shaped abrasive compound is arranged in a grid pattern on the conformable abrasive film.

15. The rotary grinding tool of claim 14, wherein adjacent precisely shaped abrasive compounds have different orientations.

16. The rotary grinding tool of claim 14, wherein adjacent precisely shaped abrasive compounds have the same orientation.

17. The rotary abrasive tool according to any one of claims 1 to 16, wherein the conformable abrasive film comprises a compliant backing layer.

18. The rotary grinding tool according to any one of claims 1 to 17, wherein the binder comprises a resin.

19. The rotary polishing tool according to any one of claims 1 to 18, wherein the precisely shaped abrasive compound is precisely positioned such that the spacing between the first precisely shaped abrasive compound and the adjacent second precisely shaped abrasive compound is substantially the same as the spacing between the second precisely shaped abrasive compound and the adjacent third precisely shaped abrasive compound.

20. The rotary grinding tool of claim 19, wherein the spacing is substantially zero, such that at least a portion of the first precisely shaped abrasive particle contacts the second precisely shaped abrasive particle along its edge.

21. The rotary grinding tool according to any one of claims 1 to 20, wherein the first substantially triangular face comprises an obtuse triangle.

22. The grinding rotary tool according to any one of claims 1 to 21, wherein the first substantially triangular face comprises an acute triangle.

23. The rotary grinding tool according to any one of claims 1 to 22, wherein the abrasive particles have a Mohs hardness of at least 8.

24. The rotary grinding tool according to any one of claims 1 to 23, wherein the precisely shaped abrasive compound has an aspect ratio of less than 3.

25. The rotary grinding tool according to any one of claims 1 to 24, wherein the cutting edge has an uneven cutting profile.

26. The rotary grinding tool of claim 25, wherein the uneven cutting profile comprises a plurality of peaks and valleys.

27. A method for grinding a work surface using a rotary grinding tool, the method comprising: Apply coolant to the working surface; The working surface is brought into frictional contact with the rotating tool, the rotating tool comprising: A cylindrical tool body, the cylindrical tool body having a curved side surface and a circular surface, the circular surface having a central opening; A conformal abrasive membrane, the conformal abrasive membrane being wrapped around the edge of the curved side surface to the circular surface, the conformal abrasive membrane comprising: A base portion, which is connected to the curved side surface; A plurality of protrusions extending from the base portion, each protrusion having a first width at the base portion and a second width at opposite ends, wherein the second width is less than the first width; The protrusion is configured to wrap around the edge and enter the central opening; A structured abrasive layer disposed on the conformal abrasive film, the structured abrasive layer comprising a plurality of precisely shaped abrasive compounds arranged in a repeating pattern. The rotating tool is moved relative to the working surface to grind at least a portion of the working surface.

28. The method of claim 27, wherein the compliant backing of the conformable abrasive membrane comprises a polymer foam layer.

29. The method according to claim 27 or 28, wherein the adhesive layer for fixing the conformable abrasive film to the tool body is a pressure-sensitive adhesive.

30. The method according to any one of claims 27 to 29, wherein the shaped abrasive composite in the composite abrasive structure comprises diamond abrasive particles in a resin binder.

31. The method according to any one of claims 28 to 30, wherein the coolant applied to the working surface is a cerium oxide-based coolant.

32. The method according to any one of claims 28 to 31, wherein the rotary tool moves relative to the working surface in a track pattern during the grinding operation.

33. The method according to any one of claims 27 to 32, wherein each formed abrasive compound has a trapezoidal face connected to a first substantially triangular face and a second substantially triangular face.

34. The method according to any one of claims 27 to 33, wherein the surface of each formed abrasive compound with a quadrilateral shape is rectangular.

35. The method according to any one of claims 27 to 33, wherein the first substantially triangular face of each formed abrasive compound is an isosceles triangle.

36. The method according to any one of claims 27 to 33, wherein the first substantially triangular face of each formed abrasive compound is an acute triangle.

37. The method according to any one of claims 27 to 36, wherein the cutting edge of each formed abrasive compound is configured to contact the working surface at a front angle between 80° and 100°.

38. A method for forming a rotary polishing tool for 3D polishing operations, the method comprising: A composite abrasive structure is provided comprising a plurality of precisely shaped abrasive compounds, each compound having a first substantially triangular face opposite to a second substantially triangular face, and a quadrilateral face connecting both the first substantially triangular face and the second substantially triangular face. The composite abrasive structure is applied to a compliant backing to form a conformable abrasive film; The conformal abrasive film is shaped into a pattern including a base portion and a plurality of protrusions extending from the base portion, each protrusion having a first width at the base portion and a second width at an opposite end, wherein the second width is smaller than the first width; The conformable abrasive film is attached to the cylindrical tool body such that: The base portion is connected to the curved side surface of the tool body; The protrusion wraps around the edge of the circular facet that joins the curved side surface to the tool body and extends into the central opening of the tool body; The conformal abrasive film is fixed to the tool body using an adhesive layer; The structured abrasive layer includes abrasive particles in the binder material.

39. The method of claim 38, wherein the composite abrasive structure comprises a plurality of precisely shaped abrasive composites, each composite having a first substantially triangular face opposite to a second substantially triangular face, and a quadrilateral-shaped surface connecting both the first substantially triangular face and the second substantially triangular face.

40. The method of claim 39, wherein the surface of the quadrilateral shape of each precisely shaped abrasive compound is rectangular.

41. The method of claim 39, wherein the face of the first substantially triangular shape of each precisely shaped abrasive compound is an isosceles triangle.

42. The method of claim 39, wherein the first substantially triangular face of each precisely shaped abrasive compound is an acute triangle.

43. The method of claim 39, wherein the structured abrasive layer comprises abrasive particles in a binder material.

44. A structured abrasive article, the structured abrasive article comprising: Base; A backing, the backing being attached to the substrate, the backing having opposing first and second main surfaces, wherein the backing comprises a compliant material; as well as A structured abrasive layer is disposed on and fixed to the first main surface, the structured abrasive layer comprising a precisely shaped abrasive compound, wherein the precisely shaped abrasive compound comprises: The face of the first essentially triangular shape that is opposite to the face of the second essentially triangular shape; A quadrilateral-shaped surface, which connects to both the first substantially triangular-shaped face and the second substantially triangular-shaped face and forms an angle with the backing; and A cutting edge is formed along one side of the quadrilateral, and a contact edge is formed along the opposite side of the quadrilateral, the contact edge being configured to attach to the backing, and wherein the contact edge is longer than the cutting edge; and The precision-formed abrasive composite comprises abrasive particles in a binder material.

45. The structured abrasive article of claim 44, wherein the precision-formed abrasive compound is precisely positioned such that the spacing between the first precision-formed abrasive compound and the adjacent second precision-formed abrasive compound is substantially the same as the spacing between the second precision-formed abrasive compound and the adjacent third precision-formed abrasive compound.

46. ​​The structured abrasive article of claim 45, wherein the spacing is substantially zero, such that at least a portion of the first precisely shaped abrasive particle contacts the second precisely shaped abrasive particle along its edge.

47. The structured abrasive article according to any one of claims 44 to 46, wherein the first substantially triangular face comprises a right-angled triangle.

48. The structured abrasive article according to any one of claims 44 to 46, wherein the first substantially triangular face comprises an obtuse triangle.

49. The structured abrasive article according to any one of claims 44 to 46, wherein the first substantially triangular face comprises an acute triangle.

50. The structured abrasive article according to any one of claims 44 to 49, wherein the binder material comprises a polymer material.

51. The structured abrasive article of claim 50, wherein the binder material comprises a thermosetting polymer material.

52. The structured abrasive article according to any one of claims 44 to 51, wherein the abrasive particles comprise diamond.

53. The structured abrasive article according to any one of claims 44 to 52, wherein the abrasive particles comprise ceramic abrasive particles.

54. The structured abrasive article according to any one of claims 44 to 53, wherein the abrasive particles have a Mohs hardness of at least 8.

55. The structured abrasive article according to any one of claims 44 to 54, wherein the precisely shaped abrasive composite has an aspect ratio of less than 3.

56. The structured abrasive article according to any one of claims 44 to 55, wherein the precisely shaped abrasive composite has an aspect ratio of less than 2 in length to thickness.

57. The structured abrasive article according to any one of claims 44 to 56, wherein the structured abrasive article further comprises a pressure-sensitive adhesive layer disposed on the second main surface.

58. The structured abrasive article according to any one of claims 44 to 57, wherein the cut edge has a non-uniform cut profile.

59. The structured abrasive article according to any one of claims 44 to 58, wherein the non-uniform cut profile comprises a plurality of peaks and valleys.

60. A method for grinding a glass workpiece, the method comprising: At least a portion of the structured abrasive layer of the structured abrasive article according to any one of claims 44 to 59 is in frictional contact with the surface of the glass workpiece; as well as The workpiece or at least one of the structured abrasive layers is moved relative to the other to grind at least a portion of the surface of the workpiece.

61. A grinding rotary tool, the grinding rotary tool comprising: A tool shank that defines the axis of rotation of the rotary tool; A cylindrical section attached to the tool shank, wherein the cylindrical section includes a ground outer surface surrounding the axis of rotation of the rotating tool; When the grinding rotary tool is operated from the tool shank, the cylindrical section facilitates grinding the edge of the workpiece between a first side and a second side of the workpiece. and The grinding outer surface includes a structured abrasive layer comprising a plurality of precisely shaped abrasive compounds arranged in a pattern on the grinding outer surface. Each of the plurality of precisely shaped abrasive compounds includes a first substantially triangular face opposite to a second substantially triangular face, and a trapezoidal face connected along a first edge to the first substantially triangular face and along a second edge to the second substantially triangular face. A third edge of each precisely shaped abrasive compound is connected to a backing and opposite a fourth edge configured to contact the workpiece.

62. The grinding rotary tool of claim 61, wherein each of the plurality of precisely shaped abrasive compounds comprises a plurality of abrasive particles in a binder.

63. The grinding rotary tool according to claim 62, wherein the plurality of abrasive particles comprise diamond particles.

64. The grinding rotary tool according to any one of claims 61 to 63, wherein the first substantially triangular face is a right triangle.

65. The grinding rotary tool according to any one of claims 61 to 64, wherein the first substantially triangular face is an acute triangle.

66. The grinding rotary tool according to any one of claims 61 to 65, wherein the first substantially triangular face is an obtuse triangle.

67. The grinding rotary tool according to any one of claims 61 to 66, wherein the fourth edge is shorter than the third edge.

68. The grinding rotary tool of claim 67, wherein the fourth edge is at least half the length of the third edge.

69. The grinding rotary tool according to any one of claims 61 to 68, wherein the aspect ratio of the thickness of the precisely shaped abrasive compound to the length of the precisely shaped abrasive compound is less than 3.

70. The grinding rotary tool according to any one of claims 61 to 69, wherein the aspect ratio of the thickness to the length of the precisely shaped abrasive compound is less than 2.

71. The grinding rotary tool according to any one of claims 61 to 70, further comprising: A flexible planar section, which is positioned opposite to the tool shank; The flexible planar segment forms a second grinding outer surface on a first side of the flexible planar segment, and the first side of the flexible planar segment generally faces away from the tool shank. The flexible planar segment forms a third grinding outer surface on its second side, the second side of the flexible planar segment facing the overall direction of the tool shank. When the second grinding outer surface is applied to a first corner adjacent to a first side of the workpiece, the flexible planar section helps to grind the first corner of the workpiece by means of the bending of the flexible planar section, using the second grinding outer surface across multiple angles relative to the axis of rotation of the rotating tool; When the second grinding outer surface is applied to a second corner adjacent to the second side of the workpiece, the flexible planar section facilitates grinding the second corner of the workpiece by means of the bending of the flexible planar section, utilizing the third grinding outer surface across multiple angles relative to the axis of rotation of the rotating tool, wherein the second side of the workpiece is opposite to the first side of the workpiece; and The flexible planar section extends beyond the outer diameter of the cylindrical section relative to the axis of rotation of the rotating tool.

72. The grinding rotary tool according to any one of claims 61 to 71, wherein the grinding rotary tool is configured to perform surface finishing on a heat-sensitive metal.

73. The grinding rotary tool according to any one of claims 61 to 72, wherein the grinding rotary tool is configured to perform surface finishing on hard or brittle materials.

74. The grinding rotary tool according to any one of claims 61 to 73, wherein the grinding rotary tool is configured to surface finish a material selected from the group consisting of: Glass; Titanium alloy; Sapphire; and ceramics.

75. The grinding rotary tool according to any one of claims 61 to 74, wherein the precisely shaped abrasive compound comprises diamond agglomerate particles.

76. The grinding rotary tool according to claim 75, wherein the volume ratio of diamond agglomerates to resin binder in the abrasive is greater than 3:

2.

77. The grinding rotary tool according to any one of claims 61 to 75, wherein the precisely shaped abrasive compound comprises: Resin; Multiple ceramic abrasive agglomerates dispersed in the resin, the ceramic abrasive agglomerates comprising individual abrasive particles dispersed in a porous ceramic matrix. At least a portion of the porous ceramic matrix comprises a glass-ceramic material; and Metal particles dispersed in the resin.

78. A component, the component comprising: The CNC machine includes a computer-controlled rotary tool holder and a workpiece platform; The workpiece refers to a partially completed cover glass sheet for fixing an electronic device to the workpiece platform, the cover glass sheet forming at least one hole; as well as The grinding rotary tool according to any one of claims 61 to 75.

79. A method for grinding the surface of a hole in a partially finished cover glass for an electronic device, the method comprising: The grinding rotary tool according to any one of claims 61 to 75 is fixed in the rotary tool holder of the CNC machine; as well as The CNC machine is operated to grind the surface of the hole in the cover glass mounted on the workpiece platform of the CNC machine.

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