Patent Application
20210347012
The invention relates to abrasive rotary tools.
Handheld electronics, such as touchscreen smartphones and tablets, often include a cover glass to provide durability and optical clarity for the devices. Production of cover glasses may use computer numerical control (CNC) machining for consistency of features in each cover glass and high-volume production. The edge finishing of the perimeter of a cover glass and various other features, such as a camera hole, is important for strength and cosmetic appearance. Typically, diamond abrasive tools, such as metal bonded diamond tools, are used to machine the cover glasses. These tools may last a relatively long time and may be effective at high cutting rates. However, the tools may leave microcracks in the cover glass that become stress concentration points, which may significantly reduce the strength of the glass. To improve the strength or appearance of the cover glasses, the edges may be polished. For example, a polishing slurry, such as cerium oxide, is typically used to polish the glass covers. However, slurry-based polishing may be slow and require multiple polishing steps. Additionally, slurry polishing equipment may be large, expensive, and unique to particular features being polished. Overall, the slurry polishing systems themselves may produce low yields, create rounded corners of the substrate being abraded, and increase labor requirements.
The disclosure is generally directed to abrasive rotary tools with enhanced adhesion of an abrasive layer. Exemplary abrasive rotary tools include a securing element configured to secure an abrasive layer to an abrasive rotary tool. The securing element may be positioned over a portion of the abrasive layer, such as a tab or end, such that contact forces on the abrasive layer do not decouple the abrasive layer from the rotary tool. In this way, an abrasive rotary tool may maintain a contact surface integrity through repeated use for extended life of the rotary tool.
In one embodiment, an abrasive rotary tool includes an abrasive assembly holder, an abrasive layer, and at least one securing element. The abrasive assembly holder includes a shank and a three-dimensional core. The shank defines an axis of rotation for the rotary tool. The three-dimensional core has an exterior surface and is adjacent to the shank. The abrasive layer is adjacent to the exterior surface and includes a contact surface. The at least one securing element is positioned over a portion of the abrasive layer and secures the abrasive layer to the abrasive assembly holder.
In another embodiment, an assembly includes a computer-controlled machining system that includes a computer controlled rotary tool holder and a substrate platform, a substrate secured to the substrate platform, and an abrasive rotary tool as described above.
In another embodiment, a method for polishing a substrate includes providing a computer-controlled machining system that includes a computer controlled rotary tool holder and a substrate platform. The method further includes securing an abrasive rotary tool as described above to the rotary tool holder of the computer-controlled machining system.
In another embodiment, a method for manufacturing an abrasive rotary tool includes positioning an abrasive layer adjacent to an exterior surface of a three-dimensional core of an abrasive assembly holder. The three-dimensional core is adjacent to a shank of the abrasive assembly holder. The abrasive layer includes a contact surface. The shank defines an axis of rotation of the rotary tool. The method further includes positioning at least one securing element over a portion of the abrasive layer, securing the abrasive layer to the abrasive assembly holder.
The details of one or more embodiments of the disclosure are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the invention will be apparent from the description and drawings, and from the claims.
Like symbols in the drawings indicate like elements. Dotted lines indicate optional or functional components, while dashed lines indicate components out of view.
The present disclosure describes abrasive rotary tools that feature a securing element that secures an abrasive layer to the abrasive rotary tool for enhanced adhesion of the abrasive layer.
An abrasive rotary tool includes an abrasive layer coupled to a support. The abrasive layer may be formed as a sheet and cut to a size and shape that, when applied to an exterior surface of the support, adheres to the support and forms the intended contact surface of the rotary tool. The support may have a geometry that includes curved surfaces and/or surfaces in multiple planes. As such, the abrasive layer may include tabs, strips, or other segmented surfaces that are cut to fit the non-planar or multi-planar surfaces of the support. During abrading, an abrasive rotary tool may experience forces that cause portions of the abrasive layer to peel, unravel, or otherwise decouple from the support. This problem may be exacerbated by the presence of a compressible layer behind the abrasive layer which, while allowing the contact surface to deform to a surface of a substrate, may also allow the interface between the abrasive layer and the rotary tool to deform and increase a likelihood of debonding of the abrasive layer from the support.
According to embodiments discussed herein, an abrasive rotary tool may include a securing element configured to secure the abrasive layer to the rotary tool. The securing element may be positioned over a portion of the abrasive layer, such as a tab or end, such that repeated forces on the abrasive layer are less likely to debond the abrasive layer from the rotary tool. In this way, an abrasive rotary tool may maintain a contact surface integrity through repeated use for extended life of the rotary tool.
Substrate 16 is mounted and secured to substrate platform 22 in a manner that facilitates precise machining of substrate 16 by machining system 12. Substrate holding fixture 24 secures substrate 16 to substrate platform 22 and precisely locates substrate 16 relative to machining system 12. Substrate holding fixture 24 may also provide a reference location for control programs of machining system 12. While the techniques disclosed herein may apply to workpieces of any materials, substrate 16 may be a component for an electronic device. In some embodiments, substrate 16 may be a display element, e.g., a transparent display element, of an electronic device, such as a cover glass for an electronic device or, more particularly, a cover glass of a smartphone touchscreen. For example, such cover glasses, back covers, or back housings may include chamfered edges for which a high degree of planarity and angularity are desired.
In some embodiments, substrate 16 may include a first major surface 2 (e.g. a top of substrate 16), a second major surface 4 (e.g. a bottom of substrate 16), and one or more edge surfaces 6 (e.g. sides of substrate 16). The area of edge surface 6 of substrate 16 is typically less than the area of the first major surface and/or second major surface of substrate 16. In some embodiments, the ratio of edge surface 6 of substrate 16 to the area of first major surface 2 of substrate 16 and/or the ratio of edge surface 6 of substrate 16 to the area of second major surface 4 of substrate 16 may be greater than 0.00001, greater than 0.0001, greater than 0.0005, greater than 0.001, greater than 0.005 or even greater than 0.01; less than 0.1, less than 0.05 or even less than 0.02. In some embodiments, a thickness of edge surface 6 measured normal to first and/or second major surfaces 2, 4, is no greater than 15 mm, no greater than 4 mm, no greater than 3 mm, no greater than 2 mm or even no greater than 1 mm. Edge surface 6 intersects first major surface 2 to form a first corner 3 and intersects second major surface 4 to form the second corner 5. In some embodiments, edge surface 6 may be substantially perpendicular to each of major surfaces 2, 4, while in other examples, edge surface 6 may include more than one edge surface, wherein at least one of the more than one edge surfaces is not perpendicular (e.g., a chamfered edge, rounded edge, curved edge or combination of edge shapes).
In the embodiment of
According to embodiments discussed herein, abrasive rotary tool 18 is configured to maintain an integrity of an abrasive layer to the tool construction while applying a contact pressure against a surface of substrate 16 over a period of time.
Abrasive assembly holder 32 may be configured to transfer a rotational force (e.g., a torque) from an abrasive rotary tool holder to an abrasive layer. Abrasive assembly holder 32 includes a shank 34 and a three-dimensional core 36. Shank 34 defines an axis of rotation for rotary tool 18 and is configured to couple to rotary tool holder 20 of
Securing element 44 is positioned over a portion of abrasive layer 40. Securing element 44 is configured to apply a force, such as a clasping or radial compressive force, to a portion of abrasive layer 40 to secure abrasive layer 40 to exterior surface 38. This force resists a debonding force caused by the abrading action of contact surface 42 on substrate 16, thereby securing abrasive layer 40 to abrasive assembly holder 32. In this way, rotary tool 18 may present a contact surface that exhibits improved longevity.
Abrasive rotary tools discussed herein may utilize securing elements to secure a variety of abrasive layers to a variety of abrasive assembly holders.
In some examples, at least a portion of the abrasive layer includes tabs, such that one or more securing elements may be configured to secure the tabs to the abrasive rotary tool.
During operation, a tangential and/or radial abrading force between contact surface 112 and a substrate may cause a leading edge of the tabs of abrasive layer 110 to peel away from exterior surface 108. Securing element 114 may oppose this peeling action, such that the tabs may be less likely to separate from exterior surface 108 and/or may separate from exterior surface 108 at a reduced rate.
In some examples, securing element 114 may only by positioned over a portion of the tabs secured by securing element 114. For example, securing element 114 only contacts the tabs of abrasive layer 110, such that securing element 114 does not contact core 106. In some examples, the tabs of abrasive layer 110 are secured to core 106 without overlap of the tabs of abrasive layer 110. For example, overlapping tabs may cause raised sections of an abrasive layer, which may increase a rate of debonding of the overlapping tabs. By securing the tabs of abrasive layer 110 without overlap, abrasive layer 110 may have a reduced variation in contact pressure from contact surface 112.
In some examples, at least a portion of the abrasive layer includes strips, such that one or more securing elements may be configured to secure the strips to the abrasive rotary tool.
During operation, a tangential and/or radial abrading force between contact surface 132 and a substrate may cause a leading edge of the strips of abrasive layer 130 to peel away from exterior surface 128, which may cause local peeling of the strips and/or loosening of the abrasive layer 130. Securing element 134 may oppose this peeling action, such that the strips may be less likely to separate from exterior surface 128 and/or may separate from exterior surface 128 at a reduced rate.
In some examples, at least a portion of the abrasive layer includes radial tabs, such that one or more securing elements may be configured to secure the radial tabs to the bottom of the abrasive rotary tool.
During operation, a tangential and/or radial abrading force between contact surface 152 and a substrate may cause a leading edge of the radial tabs of abrasive layer 150 to peel away from exterior surface 148, which may cause local peeling of the radial tabs of abrasive layer 150. Securing element 154 may oppose this peeling action, such that the strips may be less likely to separate from exterior surface 148 and/or may separate from exterior surface 148 at a reduced rate.
A variety of securing element designs and materials may be used to secure an abrasive layer to an abrasive assembly holder, as will be further discussed below. Because the securing element is configured to secure the abrasive layer to a three-dimensional core, the design and properties of the securing element may be selected based on a variety of design and operational factors of and/or regarding the abrasive rotary tool including, but not limited to: properties of the three-dimensional core, such as shape, contour, and elasticity; properties of a substrate for which the abrasive rotary tool will be abrading, such as coefficient of friction; properties of the abrasive layer of the abrasive rotary tool; properties of an adhesive between the abrasive layer and the exterior surface of the core, such as peel strength; properties of an assembly operating the abrasive rotary tool, such as an anticipated rotary force; and the like.
In some examples, the securing element secures the abrasive layer to the rotary tool using a radial force toward a rotational axis of the rotary tool. For example, a cylindrical rotary tool may have circumferential tabs, as shown in
While not shown in
A variety of materials may be used to form the securing element. In some examples, the securing element is at least one of an elastomer, a plastic, a tape, a metal, or any other material capable of applying a securing force to secure the abrasive layer to the exterior surface of the core. For example, an elastomer or a plastic may have a high elasticity, such that the securing element may be used for a variety of shapes and sizes of rotary tool and/or may maintain a relatively constant force against the abrasive layer. Elastomers that may be used include, but are not limited to, polyisoprene, polybutadiene, latex rubber, silicone, polyurethane, and the like. Plastics that may be used include shrink wrap plastics that may shrink when exposed to heat, for example. As another example, a metal may have a low elasticity, such that the securing element may exert a force on an abrasive layer and/or may remain rigid during abrading. Metals that may be used include, but are not limited to, aluminum, steel, and the like.
Securing elements discussed herein may have a variety of sizes. In some examples, securing elements may be between about 0.1 cm and about 5 cm wide. In some examples, a width of the securing element may be selected to provide an adequate adhesive force while reducing an amount of surface area of the contact surface covered by the securing element. In some examples, securing elements may be between about 0.1 mm and about 1 cm thick.
Securing elements discussed herein may be positioned at a variety of locations on the abrasive layers. In some examples, the securing elements may be positioned on any portion of the abrasive layer such that the securing element provides a force in a radial direction toward the rotational axis of the abrasive rotary tool, a force in an axial direction along the rotational axis, or a combination of both. In some examples, the securing elements may be positioned on a portion of the abrasive layer such that the securing element provides a force in axial direction.
As explained above, an abrasive layer may be configured to fit a shape of a three-dimensional core of an abrasive rotary tool. Correspondingly, a securing element may be configured to secure the abrasive layer to the three-dimensional core such that the abrasive layer is secured to the core. As such, a variety of shapes and configurations of an abrasive layer may be used for abrasive rotary tools discussed herein.
Rotary tools as discussed herein may include any number of abrasive layers. In some examples, a plurality of abrasive layers may be used on a same rotary tool. For example, a rotary tool may have a first abrasive layer having a first set of abrasive characteristics (e.g., roughness, etc.) and a second abrasive layer having a second set of abrasive characteristics. One or more abrasive layers of the plurality of abrasive layers may be secured to the rotary tool using a securing element as discussed herein. For example, a first abrasive layer on a portion of a core proximal to a shaft may be secured by a band securing element, while a second abrasive layer on a portion of the core distal to the shaft may be secured by an axial securing element.
Abrasive layers as discussed herein, such as abrasive layer 40, include a contact surface, such as contact surface 42, configured to contact and abrade one or more surfaces of a substrate. Abrading may include grinding, polishing, and any other action that removes material from the substrate. As will be appreciated by those skilled in the art, the contact surface can be formed according to a variety of methods including, e.g., molding, extruding, embossing, and combinations thereof.
The abrasive layer is not particularly limited and may include, but is not limited to, traditional coated abrasives and structured abrasives (e.g. 3M TRIZACT ABRASIVE, available from 3M Company, St. Paul, Minn.). The abrasive layer may include a base layer, e.g. backing layer, and a contact layer. The base layer may be formed from a polymeric material. For example, the base layer may be formed from thermoplastics, such as polypropylene, polyethylene, polyethylene terephthalate and the like; thermosets, such as polyurethanes, epoxy resin, and the like; or any combinations thereof. The base layer may include any number of layers. The thickness of the base layer (i.e., the dimension of the base layer in a direction normal to the first and second major surfaces) may 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.
In some examples, the contact surface of the abrasive layer includes a microstructured surface. The microstructured surface may include microstructures configured to increase a contact pressure of the contact surface on one or more surfaces of a substrate. In some embodiments, the microstructured surface may include a plurality of cavities interspaced between the outermost abrasive material of the abrasive layer. For example, the shape of the cavities may be selected from among a number of geometric shapes such as a cubic, cylindrical, prismatic, hemispherical, rectangular, pyramidal, truncated pyramidal, conical, truncated conical, cross, post-like with a bottom surface which is arcuate or flat, or combinations thereof. Alternatively, some or all of the cavities may have an irregular shape. In various embodiments, one or more of the side or inner walls that form the cavities may be perpendicular relative to the top major surface or, alternatively, may be tapered in either direction (i.e., tapered toward the bottom of the cavity or toward the top of the cavity—toward the major surface). The angle forming the taper can range from about 1 to 75 degrees, from about 2 to 50 degrees, from about 3 to 35 degrees, or from between about 5 to 15 degrees. The height, or depth, of the cavities can be at least 1 micron, at least 10 microns, or at least 500 microns, or at least 1 mm; less than 10 mm, less than 5 mm, or less than 1 mm. The height of the cavities may be the same, or one or more of the cavities may have a height that is different than any number of other cavities. In some embodiments, the cavities can be provided in an arrangement in which the cavities are in aligned rows and columns. In some instances, one or more rows of cavities can be directly aligned with an adjacent row of cavities. Alternatively, one or more rows of cavities can be offset from an adjacent row of cavities. In further embodiments, the cavities can be arranged in a spiral, helix, corkscrew, or lattice fashion. In still further embodiments, the composites can be deployed in a “random” array (i.e., not in an organized pattern).
In some examples, the contact surface comprises a plurality of precisely shaped abrasive composites. “Precisely shaped abrasive composite” refers to an abrasive composite having a molded shape that is the inverse of the mold cavity which is retained after the composite has been removed from the mold; preferably, the composite is substantially free of abrasive particles protruding beyond the exposed surfaces of the shape before the abrasive layer has been used, as described in U.S. Pat. No. 5,152,917 (Pieper et al.), which is incorporate herein by reference in its entirety. The plurality of precisely shaped abrasive composites may include a combination of abrasive particles and resin/binder forming a fixed abrasive. In some embodiments, contact surface 70 may be formed as a two-dimensional abrasive material, such as an abrasive sheet with a layer of abrasive particles held to a backing by one or more resin or other binder layers. Alternatively, the contact surface may be formed as a three-dimensional abrasive material, such as a resin or other binder layer that contains abrasive particles dispersed therein and is formed into a three-dimensional structure (forming a microstructured surface) via a molding or embossing process, for example, followed by curing, crosslinking, and/or crystallizing of the resin to solidify and maintain the three-dimensional structure. The three-dimensional structure may include a plurality of precisely shaped abrasive composites. In either embodiment, the contact surface may include an abrasive composite which has appropriate height to allow for the abrasive composite to wear during use and/or dressing to expose a fresh layer of abrasive particles. The abrasive layer may comprise a three-dimensional, textured, flexible, fixed abrasive construction including a plurality of precisely shaped abrasive composites. The precisely shaped abrasive composites may be arranged in an array to form the three-dimensional, textured, flexible, fixed abrasive construction. The abrasive layer may comprise abrasive constructions that are patterned. Abrasive layers available under the trade designation TRIZACT patterned abrasive and TRIZACT diamond tile abrasives available from 3M Company, St. Paul, Minn., are exemplary patterned abrasives. Patterned abrasive layers include monolithic rows of abrasive composites precisely aligned and manufactured from a die, mold, or other techniques.
The shape of each precisely shaped abrasive composite may be selected for the particular application (e.g., workpiece material, working surface shape, contact surface shape, temperature, resin phase material). The shape of each precisely shaped abrasive composite may be any useful shape, e.g., cubic, cylindrical, prismatic, right parallelepiped, pyramidal, truncated pyramidal, conical, hemispherical, truncated conical, cross, or post-like sections with a distal end. Composite pyramids may, for instance, have three, four sides, five sides, or six sides. The cross-sectional shape of the abrasive composite at the base may differ from the cross-sectional shape at the distal end. The transition between these shapes may be smooth and continuous or may occur in discrete steps. The precisely shaped abrasive composites may also have a mixture of different shapes. The precisely shaped abrasive composites may be arranged in rows, spiral, helix, or lattice fashion, or may be randomly placed. The precisely shaped abrasive composites may be arranged in a design meant to guide fluid flow and/or facilitate swarf removal.
The precisely shaped abrasive composites may be set out in a predetermined pattern or at a predetermined location within the abrasive layer. For example, when the abrasive layer is made by providing an abrasive/resin slurry between a backing and mold, the predetermined pattern of the precisely shaped abrasive composites will correspond to the pattern of the mold. The pattern is thus reproducible from abrasive layer to abrasive layer. The predetermined patterns may be in an array or arrangement, by which is meant that the composites are in a designed array such as aligned rows and columns, or alternating offset rows and columns. In another embodiment, the abrasive composites may be set out in a “random” array or pattern. By this is meant that the composites are not in a regular array of rows and columns as described above. It is understood, however, that this “random” array is a predetermined pattern in that the location of the precisely shaped abrasive composites is predetermined and corresponds to the mold.
An abrasive material forming the contact surface of the abrasive layer may include a polymeric material, such as a resin. In some embodiments, the resin phase may include a cured or curable organic material. The method of curing is not critical, and may include, for instance, curing via energy such as UV light or heat. Examples of suitable resin phase materials include, for instance, amino resins, alkylated urea-formaldehyde resins, melamine-formaldehyde resins, alkylated benzoguanamine-formaldehyde resins, acrylate resins (including acrylates and methacrylates), phenolic resins, urethane resins, and epoxy resins.
Examples of suitable abrasive particles for the abrasive layer include cubic boron nitride, fused aluminum oxide, ceramic aluminum oxide, heat treated aluminum oxide, white fused aluminum oxide, black silicon carbide, green silicon carbide, titanium diboride, boron carbide, silicon nitride, tungsten carbide, titanium carbide, diamond, cubic boron nitride, hexagonal boron nitride, alumina zirconia, iron oxide, ceria, garnet, fused alumina zirconia, alumina-based sol gel derived abrasive particles and the like. The alumina abrasive particle may contain a metal oxide modifier. The diamond and cubic boron nitride abrasive particles may be mono crystalline or polycrystalline. Other examples of suitable inorganic abrasive particles include silica, iron oxide, chromia, ceria, zirconia, titania, tin oxide, gamma, alumina, and the like. The abrasive particles may be abrasive agglomerate particles. Abrasive agglomerate particles typically comprise a plurality of abrasive particles, a binder, and optional additives. The binder may be organic and/or inorganic. Abrasive agglomerates may be randomly shape or have a predetermined shape associated with them.
In some embodiments, the abrasive layer, including resin, abrasive particles, and any additional additives dispersed in the resin, may be a coating on the rigid support layer. In some particular embodiments, an abrasive layer may be formed from an abrasive composite layer deposited on a base layer, the base layer may include a primer layer between the abrasive composite layer and the base layer. The base layer itself may be positioned over a backing layer with an adhesive securing the base layer to the backing layer.
In some examples, abrasive rotary tools may include an adhesive layer between the exterior surface of the core and the abrasive layer. For example, as will be explained further in
The three-dimensional core of the abrasive rotary tools discussed herein may have a variety of shapes. In some examples, the shape of the three-dimensional core may be at least one of: cylindrical, bulbous, conical, cup-shaped, and the like. The three-dimensional core of the abrasive rotary tools discussed herein may be formed from a variety of materials. In some examples, the three-dimensional core includes at least one of a metal, such as aluminum 6061, 2011, or 2024 or steel 4140, W1, or 01; a plastic, such as nylon, polycarbonate, or acrylic; an elastomer, such as nitriles, fluoroelastomers, chloroprenes, epichlorohydrins, silicones, urethanes, polyacrylates, EPDM (ethylene propylene diene monomer) rubbers, SBR (styrene butadiene rubber), butyl rubbers; and the like. In some embodiments, the three-dimensional core may include a foam, e.g. a foam rubber.
In some examples, the three-dimensional core may include more than one layer. For example, the three-dimensional core may include a metal and an elastomer or a plastic and an elastomer. In some examples, such as
In some embodiments, the rigid layer and the elastic layer, or any other layer of the three-dimensional core, may each be composed of a material selected according to softness. Softness of a material may be correlated with the conformability of the material; generally, a softer material may have a higher conformability at a given contact pressure. Softness may be represented by and selected based on a variety of properties of each material of the rigid support layer and the elastic layer. For example, a softer material may be a material with a lower hardness (as indicated using any appropriate hardness scale, such as Shore A or Shore OO), a material with a lower elastic modulus, a material with a higher compressibility (typically quantified via a material's Poisson's ratio or deflection), or a material with a modified structure, such as containing a plurality of gas inclusions such as a foam, etc.
In some embodiments, the rigid layer and the elastic layer may each be composed of a material selected according to hardness. Hardness may represent a measure of each of the rigid support layer and the elastic layer to deform in response to a force. In some cases, the hardness may be most appropriately measured using different scales for the rigid support layer and the elastic layer (e.g., Shore A durometer for the elastic layer and Rockwell scale for the rigid support layer). In some examples, the elastic layer has a Shore A hardness of less than 80. In some examples, the three-dimensional core, such as an elastic layer, a rigid layer, or both, has a Shore A hardness of greater than 25. In some embodiments, at least one of the Shore A, Shore D and Shore OO hardness of the rigid layer is greater than the corresponding Shore A, Shore D or Shore OO hardness of the elastic layer.
In some examples, the three-dimensional core includes a rigid layer that includes at least one of a metal layer and plastic layer adjacent the elastic layer. In some examples, at least a portion of the three-dimensional core and shank are a unitary body. In some examples, the elastic layer comprises at least one of an elastomer, a foam, a fabric, or a nonwoven material. Suitable elastomers may include thermoset elastomers such as, for example, nitriles, fluoroelastomers, chloroprenes, epichlorohydrins, silicones, urethanes, polyacrylates, EPDM (ethylene propylene diene monomer) rubbers, SBR (styrene butadiene rubber), butyl rubbers, etc.
In various embodiments, abrasive rotary tools as described herein may be suitable for edge or major surface grinding a cover glass. For example, a cover glass may include various surfaces for which a high pressure on a small surface area may create a high peel force on an abrasive layer of an abrasive rotary tool.
Cover glass 500 includes a first major surface 502 opposing a second major surface 504. Generally, but not always, major surfaces 502, 504 are planar surfaces. Edge surface 506 follows the perimeter of major surfaces 502, 504, the perimeter including rounded corners 508. Edge surface 506 intersects first major surface 502 at a first corner and second major surface 504 at a second corner, the first and second corners, generally, extends around the entire perimeter of the substrate.
To provide an increased resistance to cracking and improved appearance, the surfaces of cover glass 500, including major surfaces 502, 504 and edge surface 506 should be smoothed to the extent practical during manufacturing of cover glass 500. In addition, as disclosed herein, abrasive rotary tools may be used to reduce edge surface roughness, such as edge surface 506 and corners 508 using a CNC machine prior. An abrasive rotary tool with enhanced adhesion of an abrasive layer may more consistently abrade edge surface 506 and corners 508, as a contact surface of the abrasive layer may remain intact as abrasive layer remains coupled to the abrasive rotary tool.
In some examples, the method includes cutting an abrasive material to form an abrasive layer, such as abrasive layer 40 (600). For example, a rotary die cutting machine may cut a sheet of an abrasive material to form abrasive layer 40. The die may be configured to cut abrasive layer 40 such that abrasive layer 40 forms a desire contact surface, such as contact surface 42, after coupling of abrasive layer 40 to a three-dimensional core, such as three-dimensional core 36.
In some examples, the method includes applying an adhesive to at least one of exterior surface 38 and abrasive layer 40 before positioning abrasive layer 40 on exterior surface 38. For example, an adhesive layer may be applied to one or both of exterior surface 38 and/or a backing surface, opposite contact surface 42, of abrasive layer 40 to secure adhesive layer 40 to exterior surface 38 using an adhesive force of the adhesive layer. In some examples, the adhesive force of the adhesive layer is less than a total securing force required for securing abrasive layer 40 to abrasive rotary tool 18 for a desired period of operation. In some examples, abrasive layer 40 may already include an adhesive, such as an adhesive backing.
The method includes positioning abrasive layer 40 adjacent to exterior surface 38 of three-dimensional core 36 of abrasive assembly holder 32 (610). For example, the backing surface of abrasive layer 40 may substantially contact exterior surface 38 of core 36, such as greater than 90% of the backing surface contacting exterior surface 38.
The method includes positioning at least one securing element 44 over a portion of abrasive layer 40, securing abrasive layer 40 to abrasive assembly holder 32 (620). For example, securing element 44 may be placed, clasped, shrank, cured, heated, or received any other action that positions securing element 44 on abrasive layer 40, such that abrasive layer 40 is secured to abrasive assembly holder 32.
Select embodiments of the present disclosure include, but are not limited to, the following:
In a first embodiment, the present disclosure provides an abrasive rotary tool, comprising:
an abrasive assembly holder including:
an abrasive layer adjacent to the exterior surface, wherein the abrasive layer includes a contact surface; and
at least one securing element positioned over a portion of the abrasive layer, securing the abrasive layer to the abrasive assembly holder.
In a second embodiment, the present disclosure provides an abrasive rotary tool according to the first embodiment, wherein the three-dimensional core includes at least one side-wall adjacent to the exterior surface and the securing element secures the abrasive layer to the at least one side wall of the three-dimensional core.
In a third embodiment, the present disclosure provides an abrasive rotary tool according to the first or second embodiment, wherein at least a portion of the abrasive layer includes tabs.
In a fourth embodiment, the present disclosure provides an abrasive rotary tool according to the third embodiment, wherein the securing element is positioned over at least a portion of the tabs.
In a fifth embodiment, the present disclosure provides an abrasive rotary tool according to the fourth embodiment, wherein the securing element is only positioned over at least a portion of the tabs.
In a sixth embodiment, the present disclosure provides an abrasive rotary tool according to any one of the first through fifth embodiments, wherein the abrasive layer is secured to the three-dimensional core without overlap of the abrasive layer.
In a seventh embodiment, the present disclosure provides an abrasive rotary tool according to any one of the first through sixth embodiments, wherein the contact surface of the abrasive layer includes a microstructured surface.
In an eighth embodiment, the present disclosure provides an abrasive rotary tool according to any one of the first through seventh embodiments, wherein the contact surface comprises a plurality of precisely shaped abrasive composites.
In a ninth embodiment, the present disclosure provides an abrasive rotary tool according to any one of the first through eighth embodiments, wherein at least a portion of the three-dimensional core and shank are a unitary body.
In a tenth embodiment, the present disclosure provides an abrasive rotary tool according to any one of the first through ninth embodiments, wherein the securing element is at least one of an elastomer, a plastic, a tape, and a metal.
In an eleventh embodiment, the present disclosure provides an abrasive rotary tool according to the tenth embodiment, wherein the elastomer is at least one of an O-ring, a band, a wrap, a thermally shrinkable sleeve, and a flange.
In a twelfth embodiment, the present disclosure provides an abrasive rotary tool according to the tenth embodiment, wherein the plastic is at least one of an O-ring, a band, a wrap, a thermally shrinkable sleeve, and a flange.
In a thirteenth embodiment, the present disclosure provides an abrasive rotary tool according to the tenth embodiment, wherein the securing element is only positioned over at least a portion of the tabs.
In a fourteenth embodiment, the present disclosure provides an abrasive rotary tool according to any one of the first through thirteenth embodiments, wherein the three-dimensional core includes at least one of a metal, elastomer, and a plastic.
In a fifteenth embodiment, the present disclosure provides an abrasive rotary tool according to any one of the first through fourteenth embodiments, wherein the three-dimensional core includes a metal and an elastomer or a plastic and an elastomer.
In a sixteenth embodiment, the present disclosure provides an abrasive rotary tool according to any one of the first through fifteenth embodiments, wherein the three-dimensional core includes an elastic layer which includes the exterior surface.
In a seventeenth embodiment, the present disclosure provides an abrasive rotary tool according to the sixteenth embodiment, wherein the three-dimensional core includes at least one of a metal layer and plastic layer adjacent the elastic layer.
In an eighteenth embodiment, the present disclosure provides an abrasive rotary tool according to the sixteenth or seventeenth embodiment, wherein the elastic layer has a Shore A hardness of less than 80.
In a nineteenth embodiment, the present disclosure provides an abrasive rotary tool according to any one of the sixteenth through eighteenth embodiments, wherein the elastic layer comprises at least one of an elastomer, a foam, a fabric, or a nonwoven material.
In a twentieth embodiment, the present disclosure provides an abrasive rotary tool according to any one of the first through nineteenth embodiments, wherein the three-dimensional core has a Shore A hardness of greater than 25.
In a twenty-first embodiment, the present disclosure provides an abrasive rotary tool according to any one of the first through twentieth embodiments, wherein the three-dimensional core includes a largest radial dimension and the shank includes a largest radial dimension and wherein the largest radial dimension of the core is greater than the largest radial dimension of the shank.
In a twenty-second embodiment, the present disclosure provides an abrasive rotary tool according to any one of the first through twentieth embodiments, wherein the three-dimensional core includes a largest radial dimension and the shank includes a largest radial dimension and wherein the radial dimension of the core is less than or equal to the radial dimension of the shank.
In a twenty-third embodiment, the present disclosure provides an abrasive rotary tool according to any one of the first through twenty-second embodiments, wherein the shank and at least a portion of the core are metal.
In a twenty-fourth embodiment, the present disclosure provides an abrasive rotary tool according to any one of the first through twenty-third embodiments, further comprising an adhesive layer disposed between the abrasive layer and the exterior surface of the core.
In a twenty-fifth embodiment, the present disclosure provides an abrasive rotary tool according to the twenty-fourth embodiment, wherein the adhesive layer includes a pressure sensitive adhesive.
In a twenty-sixth embodiment, the present disclosure provides an abrasive rotary tool according to any one of the first through twenty-fifth embodiments, wherein the core includes a retaining channel.
In a twenty-seventh embodiment, the present disclosure provides an abrasive rotary tool according to the twenty-sixth embodiment, wherein the securing element is contained in at least a portion of the retaining channel.
In a twenty-eighth embodiment, the present disclosure provides an assembly, comprising:
a computer-controlled machining system comprising a computer controlled rotary tool holder and a substrate platform;
a substrate secured to the substrate platform; and
an abrasive rotary tool of any of the first through twenty-seventh embodiments.
In a twenty-ninth embodiment, the present disclosure provides an assembly according to the twenty-eighth embodiment, wherein the substrate is a component for an electronic device.
In a thirtieth embodiment, the present disclosure provides an assembly according to the twenty-ninth embodiment, wherein the component for an electronic device is a transparent, display element.
In a thirty-first embodiment, the present disclosure provides a method for polishing a substrate, comprising:
providing a computer-controlled machining system including a computer controlled rotary tool holder and a substrate platform;
securing an abrasive rotary tool to the rotary tool holder of the computer-controlled machining system, wherein the abrasive rotary tool comprises:
operating the computer-controlled machining system to abrade a contact surface of the substrate using the abrasive layer of the abrasive rotary tool.
In a thirty-second embodiment, the present disclosure provides a method according to the thirty-first embodiment, further comprising:
positioning an abrasive layer adjacent to an exterior surface of a three-dimensional core of an abrasive assembly holder, wherein the three-dimensional core is adjacent to a shank of the abrasive assembly holder, wherein the abrasive layer includes a contact surface, wherein the shank defines an axis of rotation of the rotary tool; and
positioning at least one securing element over a portion of the abrasive layer, securing the abrasive layer to the abrasive assembly holder.
In a thirty-third embodiment, the present disclosure provides an assembly according to the thirty-second embodiment, further comprising applying an adhesive to at least one of the exterior surface and the abrasive layer before positioning the abrasive layer.
The operation of the present disclosure will be further described with regard to the following detailed examples. These examples are offered to further illustrate the various specific and preferred embodiments and techniques. It should be understood, however, that many variations and modifications may be made while remaining within the scope of the present disclosure.
Various embodiments of the invention have been described. These and other embodiments are within the scope of the following claims.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/IB2019/058194 | 9/26/2019 | WO | 00 |
| Number | Date | Country | |
|---|---|---|---|
| 62740616 | Oct 2018 | US |
