[0001] This application claims the benefit of priority under 35 U.S.C. § 119 of U.S.

Provisional Application Serial No. 62/778,649 filed on December 12, 2018, the content of which is relied upon and incorporated herein by reference in its entirety.

Field

[0002] The present disclosure relates generally to a grinding wheel and more particularly to a grinding wheel made by additive manufacturing methods.

Background

[0003] Grinding wheels can be used in the manufacture of articles, such as glass articles, including the edge grinding and/or polishing of glass sheets used for display applications, including televisions and hand-held devices, such as telephones and tablets. For example, during grinding and/or polishing processes of glass substrates, a grinding wheel and glass substrate can move relative to each other to grind and/or polish the edges of the glass substrate. This process tends to generate a large amount of heat and glass particles.

[0004] Conventional grinding wheels include, for example, bonded grinding wheels, which are typically manufactured by pressing or extruding blends of abrasive materials, bonding materials, and other additives into a green shape and then sintering at a relatively high temperature to fuse powder particles. An alternative approach utilizes sintering during the pressing process to create the component in-situ. However, these manufacturing processes lack design freedom for producing relatively complex geometries, including geometries that may better control grinding temperatures and reduce the accumulation of glass particles or other debris in the contact area. Such relatively complex geometries may further improve grinding accuracy and efficiency.

Summary

[0005] Embodiments disclosed herein include a grinding wheel. The grinding wheel includes a core region extending around a central axis and a grinding region circumferentially surrounding the core region. The grinding wheel also includes at least one of: a plurality of non-machined flow channels, each flow channel of the plurality of non-machined flow channels extending along a radial distance between the central axis and the grinding region, wherein each flow channel includes a radial axis, an annular axis, and an axial axis; and a repetitive pattern comprising lattice structures on or within at least one of the interior and the exterior of the grinding wheel.

[0006] Embodiments disclosed herein also include a method for making a grinding wheel the method includes impinging an energy source on a feedstock material to fuse the feedstock material into a three-dimensional object having a predetermined shape, the pre-determined shape being a grinding wheel. The grinding wheel includes a core region extending around a central axis and a grinding region circumferentially surrounding the core region. The grinding wheel also includes at least one of: a plurality of non-machined flow channels, each flow channel of the plurality of non-machined flow channels extending along a radial distance between the central axis and the grinding region, wherein each flow channel includes a radial axis, an annular axis, and an axial axis; and a repetitive pattern comprising lattice structures on or within at least one of the interior and the exterior of the grinding wheel.

[0007] Additional features and advantages of the embodiments disclosed herein will be set forth in the detailed description which follows, and in part will be readily apparent to those skilled in the art from that description or recognized by practicing the disclosed embodiments as described herein, including the detailed description which follows, the claims, as well as the appended drawings.

[0008] It is to be understood that both the foregoing general description and the following detailed description present embodiments intended to provide an overview or framework for understanding the nature and character of the claimed embodiments. The accompanying drawings are included to provide further understanding, and are incorporated into and constitute a part of this specification. The drawings illustrate various embodiments of the disclosure, and together with the description serve to explain the principles and operations thereof.

Brief Description of the Drawings

[0009] FIG. l is a schematic view of a grinding wheel in accordance with exemplary embodiments disclosed herein;

[0010] FIG. 2 is a schematic view of a grinding wheel in accordance with exemplary embodiments disclosed herein; [0011] FIG. 3 is a partial enlarged view of a grinding in accordance with exemplary embodiments disclosed herein;

[0012] FIG. 4 is an enlarged view of a flow channel as viewed from an outer periphery of a grinding wheel in accordance with exemplary embodiments disclosed herein;

[0013] FIG. 5 is a middle plane cross-sectional view of a grinding wheel in accordance with exemplary embodiments disclosed herein;

[0014] FIG. 6 is a middle plane cross-sectional view of a grinding wheel in accordance with exemplary embodiments disclosed herein;

[0015] FIG. 7 is a schematic view of a grinding wheel comprising a repetitive pattern on the exterior of a core region in accordance with exemplary embodiments disclosed herein;

[0016] FIG. 8 is a partial cross-sectional view illustrating the inside of a core region of a grinding wheel in accordance with exemplary embodiments disclosed herein;

[0017] FIG. 9 is a schematic view of lattice structures in accordance with exemplary embodiments disclosed herein; and

[0018] FIGS. 10A and 10B are photographs of grinding wheels in accordance with exemplary embodiments disclosed herein.

Detailed Description

[0019] Reference will now be made in detail to the present preferred embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings.

Whenever possible, the same reference numerals will be used throughout the drawings to refer to the same or like parts. However, this disclosure may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

[0020] Ranges can be expressed herein as from“about” one particular value, and/or to “about” another particular value. When such a range is expressed, another embodiment includes from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations, for example by use of the antecedent“about,” it will be understood that the particular value forms another embodiment. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint.

[0021] Directional terms as used herein - for example up, down, right, left, front, back, top, bottom, height, width - are made only with reference to the figures as drawn and are not intended to imply absolute orientation. [0022] Unless otherwise expressly stated, it is in no way intended that any method set forth herein be construed as requiring that its steps be performed in a specific order, nor that with any apparatus specific orientations be required. Accordingly, where a method claim does not actually recite an order to be followed by its steps, or that any apparatus claim does not actually recite an order or orientation to individual components, or it is not otherwise specifically stated in the claims or description that the steps are to be limited to a specific order, or that a specific order or orientation to components of an apparatus is not recited, it is in no way intended that an order or orientation be inferred, in any respect. This holds for any possible non-express basis for interpretation, including: matters of logic with respect to arrangement of steps, operational flow, order of components, or orientation of components; plain meaning derived from grammatical organization or punctuation, and; the number or type of embodiments described in the specification.

[0023] As used herein, the singular forms "a," "an" and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to“a” component includes aspects having two or more such components, unless the context clearly indicates otherwise.

[0024] As used herein, the term“non-machined” refers to a feature, such as a flow channel, that is incorporated into a structure, such as a grinding wheel, without using a mechanical means, such as drilling, grinding, or cutting, to remove solid material from the structure in order to incorporate the feature. For example, non-machined features, such as flow channels can be incorporated into structures, such as grinding wheels, by using additive manufacturing methods as described herein.

[0025] As used herein, the terms“radial”,“annular”, and“axial” when referencing an axis of a flow channel as described herein, refer to an extension direction of the axis relative to the radius, annulus (e.g., circumference), and axis of the grinding wheel into which the flow channel is incorporated. Specifically, a radial axis of a flow channel extends in a radial direction of the grinding wheel, an annular axis of a flow channel extends in an annular direction of the grinding wheel, and an axial axis of a flow channel extends in an axial direction of the grinding wheel.

[0026] As used herein, the dimensional magnitude of a radial axis is referred to as a “length”, the dimensional magnitude of an annular axis is referred to as a“width” and the dimensional magnitude of an“axial axis” is referred to as a“height” although it is to be understood that the ultimate extension direction of these axes depends on the orientation of the grinding wheel. [0027] As used herein, the term“lattice structures” refers to structures comprising repeating patterns of solid materials and void space, wherein the repeating patterns have, for example, web-like configurations and can include, for example, X, Supported X, Hexagon, and Diamond patterns as illustrated herein, and can for example comprise at least about 50%, such as at least about 60%, and further such as at least about 70%, and yet further such as at least about 80%, and still yet further such as at least about 90%, such as from about 50% to about 95%, and further such as from about 60% to about 90% of void space relative to the total volume of the lattice structures.

[0028] FIG. 1 illustrates a grinding wheel 100 in accordance with exemplary embodiments disclosed herein. Grinding wheel 100 includes a core region 110, comprising a non-abrasive section 111, extending around a central axis 113 and a grinding region 112 circumferentially surrounding the core region 110. Grinding wheel 100 also includes a plurality of non- machined flow channels 120, each flow channel of the plurality of non-machined flow channels 120 extending along a radial distance between the central axis 113 and the grinding region 112.

[0029] As shown in FIG. 1, each flow channel of the plurality of flow channels 120 has a non-circular cross-section. Specifically, each flow channel of the plurality of flow channels 120 has a substantially parallelogram-shaped cross-section, although other flow channel shapes are within the scope of embodiments disclosed herein. For, example, flow channels having circular or elliptical cross-sections (not shown) are within the scope of embodiments disclosed herein.

[0030] FIG. 2 illustrates a grinding wheel 100 that is also in accordance with exemplary embodiments disclosed herein. Grinding wheel includes a core region 110 and a grinding region 211, wherein the grinding wheel 100 is of unitary construction such that the grinding region 211 is comprised of the same or similar material as the core region 110. Accordingly, in the embodiment illustrated in FIG. 2, the core region 110 and the grinding region 211 can each comprise abrasive materials and bonding materials for example, in volume percentages as set forth herein. As with the embodiment illustrated in FIG. 1, grinding wheel 100 also includes a plurality of non-machined flow channels 120.

[0031] Referring now to FIG. 3, a partial enlarged view of a grinding wheel 100 is shown in accordance with exemplary embodiments disclosed herein. As shown in FIG. 3, a flow channel among the plurality of flow channels 120 is highlighted, the flow channel comprising a radial axis, an annular axis, and an axial axis, wherein the length of the radial axis is shown by L, an inner width of the annular axis is shown by W, and an outer height of the axial axis is shown by H.

[0032] In certain exemplary embodiments, a ratio of a length L of the radial axis and a height H of the axial axis nearest to an outer periphery of the grinding region is at least about 5, such as at least about 10, and further such as at least about 15, including from about 5 to about 500, such as from about 10 to about 100, and further such as from about 15 to about 50. In certain exemplary embodiments, a ratio of the length L of the radial axis and a width W of the annular axis nearest to an outer periphery of the grinding region is at least about 5 such as at least about 10, and further such as at least about 15, including from about 5 to about 500, such as from about 10 to about 100, and further such as from about 15 to about 50.

[0033] In certain exemplary embodiments, a height H of the axial axis changes along a length L of the radial axis. For example, embodiments disclosed herein include those in which the height H of the axial axis increases along the length L of the radial axis between the core region and the grinding region. Embodiments disclosed also include those in which the height H of the axial axis decreases along the length L of the radial axis between the core region and the grinding region.

[0034] In certain exemplary embodiments, a height H of the axial axis remains relatively constant along a length L of the radial axis.

[0035] In certain exemplary embodiments, a width W of the annular axis changes along a length L of the radial axis. For example, embodiments disclosed herein include those in which the width W of the annular axis increases along the length L of the radial axis between the core region and the grinding region. Embodiments disclosed also include those in which the width W of the annular axis decreases along the length L of the radial axis between the core region and the grinding region.

[0036] In certain exemplary embodiments, a width W of the annular axis remains relatively constant along a length L of the radial axis.

[0037] FIG. 4 shows an enlarged view of a flow channel 120 as viewed from an outer periphery of a grinding wheel in accordance with exemplary embodiments disclosed herein.

A cross-section of flow channel 120 nearest to the central axis of the grinding wheel is shown as parallelogram 410. A cross-section of flow channel 120 nearest to an outer periphery of the grinding region is shown as parallelogram 420. As can be seen from FIG. 4, while the height H of the axial axis remains relatively constant along the length L of the radial axis of flow channel 120, the width of the annular axis changes along the length L of the radial axis, such that the annular axis has a larger width W2 nearest to an outer periphery of the grinding region than its width W1 nearest to the central axis of the grinding wheel.

[0038] Embodiments disclosed herein also include those in which at least one of an orientation of the radial axis, the axial axis, and the annular axis changes along a length of the radial axis of a flow channel. For example, as shown in FIG. 4, not only does the width of the annular axis increase between the central axis and the outer periphery of the grinding wheel but its orientation changes such that parallelogram 420 is more steeply angled than parallelogram 410. In other words, orientation of annular axis changes along the length L of radial axis such that the cross-sectional profile of flow channel 120 effectively“twists” along that length.

[0039] Embodiments disclosed herein further include those in which at least one flow channel has at least one of a radial axis length or orientation, an axial axis height or orientation, and an annular axis width or orientation that is different from a at least one of a radial axis length or orientation, an axial axis height or orientation, and an annular axis width or orientation of at least one other flow channel. For example, embodiments disclosed herein can include those in which a grinding wheel includes a plurality of flow channels, wherein an annular axis of one or more flow channels changes along a length L of a flow channel as shown in FIG. 4 and a radial axis, axial axis, and/or annular axis of one or more other flow channels of the grinding wheel changes in a different manner.

[0040] Embodiments disclosed herein additionally include those in which the grinding wheel includes at least one annular flow channel extending around an area within the core region, wherein the at least one annular flow channel intersects at least one of the plurality of non-machined flow channels at a radial distance between the central axis and the grinding region. For example, FIG. 5 shows a middle plane cross-sectional view of a grinding wheel that includes a first plurality of non-machined flow channels 510 extending along a radial distance between the central axis 113 and the at least one annular flow channel 530 and a second plurality of non-machined flow channels 520 extending along a radial distance between the at least one annular flow channel 530 and a grinding region 112.

[0041] In certain exemplary embodiments, the radial axis of at least one of the first plurality of non-machined flow channels is not co-axial with the radial axis of at least one of the second plurality of non-machined flow channels. For example, the embodiment of FIG. 5 the radial axes of the first plurality of non-machined flow channels 510 are not co-axial with the radial axes of the second plurality of non-machined flow channels 520 even though the angular orientation of proximate flow channels of the first and second pluralities of non- machined flow channels 510, 520 have a similar angular orientation between the central axis 113 and the grinding region 112. In contrast, FIG. 6 shows a middle plane cross-sectional view of a grinding wheel wherein proximate flow channels of the first and second pluralities of non-machined flow channels 510, 520 are not co-axial and have a different angular orientation between the central axis 113 and the grinding region 112.

[0042] Embodiments disclosed herein also include those in which the radial axis at least one of the first plurality of non-machined flow channels is co-axial with the radial axis of at least one of the second plurality of non-machined flow channels.

[0043] FIG. 7 illustrates an exemplary grinding wheel 100 that includes a repetitive pattern 710 on an exterior of a core region 110 of the grinding wheel 100. In certain exemplary embodiments, the repetitive pattern 710 may comprise one or more lattice structures on the exterior of the core region 110. Exemplary embodiments also include those as shown in FIG.

8, wherein a repetitive pattern 710 may comprise one or more lattice structures within the interior of the core region 110. Such repetitive pattern may also be present in other portions of the grinding wheel, such as the grinding region. The repetitive pattern 710 comprising lattice structures can reduce the total weight of the grinding wheel and save overall manufacturing costs of articles, such as glass sheets, that are manufactured using the grinding wheel. Moreover, the lighter weight design allows for more accurate tool paths in high speed operation. The repetitive pattern 710 of lattice structures may include at least one of any suitable design, for example, X, Supported X, Hexagon, and Diamond patterns as shown, for example, in FIG.9. It should be understood that the illustrated patterns are exemplary only and should not be construed to limit the scope of embodiments disclosed herein.

[0044] Embodiments disclosed herein also include those in which the void space in lattice structures are at least partially filled with at least one material, such as, for example, a filler material having a lower density than a solid material comprising a web-like patterned framework (e.g., as shown in FIG. 9) of the lattice structure. Such material can, for example, provide structural support as well as other functionalities, such as lubrication (e.g., with material such as HBN or M0S2), thermal conductivity (e.g., with materials such as aluminum nitride), improved surface finish, or reduced tool wear.

[0045] Embodiments comprising a repetitive pattern, as illustrated, for example, in FIG. 7-

9, including a repetitive pattern that comprises one or more lattice structures can be combined with any of the embodiments disclosed herein, wherein the grinding wheel comprises a plurality of non-machined flow channels, as illustrated, for example, in FIGS. 1-6.

Accordingly, embodiments disclosed herein can comprise at least one of a plurality of non- machined flow channels, for example, as illustrated in FIGS. 1-6, and a repetitive pattern, for example as illustrated in FIGS. 7-9, including a repetitive pattern that comprises one or more lattice structures, for example, as illustrated in FIGS. 8-9.

[0046] In certain exemplary embodiments, the grinding wheel comprises a composition comprising from about 5% to about 50%, such as from about 12.5% to about 37.5% of at least one abrasive material by volume and from about 50% to about 95%, such as from about 62.5% to about 87.5% of at least one bonding material by volume. Examples of specific abrasive materials and bonding materials that may be used in the manufacture of grinding wheels in accordance with embodiments disclosed herein are described in more detail below.

[0047] While embodiments disclosed herein include grinding wheels of unitary

construction, wherein, as shown, for example, in FIG. 2, the grinding region 211 comprises the same or similar materials as the core region 110, including, for example, the same or similar volume percentages of abrasive materials and bonding materials in both the core and grinding regions, embodiments disclosed herein also include those in which, as shown for example, in FIG. 1, the composition of the core and grinding regions differ. For example, embodiments disclosed herein include those in which the core region and the grinding region each comprise abrasive materials and bonding materials but the grinding region 211 has a relatively higher percentage of abrasive material than the core region 110, such as, for example, at least 5% more, such as at least 10% more, and further such as at least 20% more, and yet further such as at least, 35% more, and still yet further such as at least 50% more, including from about 5% to about 500%, such as from about 10% to about 200% more abrasive material by volume. Embodiments disclosed herein also include those in which the core region is essentially free of abrasive material.

[0048] Embodiments disclosed herein include those in which additive manufacturing (AM) methods are used to make three dimensional objects such as grinding wheels. AM is a technology that is based on fusing layer upon layer (i.e., adding material, as opposed to subtracting material in conventional manufacturing) to fabricate three-dimensional (3D) shapes. AM enables the production of complex-shaped parts, which can be quickly and precisely manufactured on one piece of equipment with a minimal number of processing steps.

[0049] An exemplary AM method is termed Powder Bed Fusion (PBF). The PBF process uses an energy source, which impinges directly on a powder feedstock material so that only selected portions of the powder material are impacted. The use of the energy source in this manner allows layers of different shapes to be rapidly fused, enabling complex objects with intricate internal structures to be produced. The energy source fuses the material by scanning the cross-sections (or layers) generated, for example, by a 3D modeling program. This layer- based process is, therefore, additive as compared to conventional manufacturing, which is subtractive and requires eliminating unwanted part features during post-processing.

[0050] Accordingly, embodiments disclosed herein include methods for making grinding wheels that include impinging an energy source on a feedstock material to fuse the feedstock material into a three-dimensional object having a predetermined shape, the pre-determined shape being a grinding wheel having a core region extending around a central axis and a grinding region circumferentially surrounding the core region. Such grinding wheels can have a plurality of non-machined flow channels, each flow channel of the plurality of non- machined flow channels extending along a radial distance between the central axis and the grinding region. Such grinding wheels can also have any or all of the geometrical configurations and/or features shown and described with reference to FIGS. 1-9.

[0051] The step of impinging the energy source on the feedstock material can include repeatedly scanning the energy source over the feedstock material in a manner determined by a three-dimensional modeling program, such as a computer-generated modeling program in accordance with methodology known to persons of ordinary skill in the art. Impinging the energy source on the feedstock material can, for example, include at least one of PBF, selective laser sintering, selective laser melting, electron-beam melting, direct metal laser sintering, directed energy deposition, laser metal deposition, fused deposition modeling, fused filament fabrication, stereolithography, laminated object manufacturing, polyjet, and material jetting in accordance with methodology known to persons of ordinary skill in the art.

[0052] Exemplary embodiments include those in which the feedstock material includes at least one abrasive material and at least one bonding material. The at least one abrasive material may, for example, include at least one of diamond, cubic boron nitride (CBN), one or more types of carbides, nitrides, carbonitrides, oxides or borides of one or more metallic elements selected from aluminum and Groups IVB, VB and VIB of the Periodic Table including aluminum oxide (AI2O3), silicon carbide (SiC), titanium carbide (TiC), tantalum carbide (TaC), niobium carbide (NbC), and tantalum niobium carbide (TaNbC). In certain exemplary embodiments, the at least one abrasive material may be at least partially coated with, for example, at least one of titanium (Ti), silver (Ag), copper (Cu), nickel (Ni), chromium (Cr), and silicon (Si).

[0053] The at least one bonding material may, for example, include at least one of nickel (Ni), boron (B), copper (Cu), iron (Fe), ethylene glycol monomethyl ether, polyethylene glycol, polyvinyl alcohol (PVA), polyvinyl butyral (PVB), and polyvinylpyrrolidone (PVP). In certain exemplary embodiments, the feedstock material may also include at least one bonding modifier that includes, for example, at least one of hexagonal boron nitride (HBN), molybdenum disulfide (M0S2), chromium carbide (CrC), nichrome (NiCr), Molybdenum- Boron (MoB), Cobalt-Chromium (CoCr), cordierite, spinel, mullite, yttrium oxide, and zircon.

[0054] In certain exemplary embodiments, the feedstock material comprises a composition comprising from about 5% to about 50%, such as from about 12.5% to about 37.5% of at least one abrasive material by volume and from about 50% to about 95%, such as from about 62.5% to about 87.5% of at least one bonding material by volume.

[0055] Embodiments disclosed herein include those in which an entire grinding wheel is manufactured by an AM process and those in which only a portion of the grinding wheel is manufactured by an AM process (with the remainder of the grinding wheel manufactured by another process, such as, for example, a process involving at least one of conventional sintering, pressing, machining, plating, etc.). For example, in certain exemplary

embodiments, a grinding wheel of unitary construction can be entirely manufactured using an AM process, wherein the grinding region comprises the same or similar materials as the core region. Grinding wheels wherein the composition of the core region and the grinding region differ can also be entirely manufactured using an AM process. In addition, embodiments disclosed herein include those in which a at least a portion of at least one of a core region and a grinding region is not manufactured by an AM process. For example, embodiments disclosed herein include those in which a core region is entirely manufactured by an AM process and at least a portion of a grinding region, such as an outermost portion of a grinding region, is not manufactured by an AM process (and is, instead, manufactured by an alternative process, such as, for example, a process involving at least one of conventional sintering, pressing, machining, plating, etc.).

[0056] Example

[0057] Embodiments herein are further illustrated with reference to the following non limiting example:

[0058] 316L stainless steel powder was used to produce a grinding wheel using a laser PBF additive manufacturing process. The 316L powder was processed in an EOS M270 machine equipped with a Yb-fiber laser (beam dimeter of about 100 pm and wavelength of about 1068 nm) with maximum power of about 200 W. The powder particles were generally spherical, produced by inert gas atomization, with a size distribution of about 15-45 pm. The grinding wheel was printed at 40 pm layer thickness on a 1045 steel plate, and separated after the build using wire EDM (electrical -discharge machining). The grinding wheel was then plated using pure Ni bond and 41-49 pm WWS-400 mesh uncoated diamond at a 37.5 vol% (150% concentration). FIG. 10A shows the grinding wheel before plating diamond onto the periphery and FIG. 10B shows the grinding wheel after diamond plating.

[0059] While the above embodiments have been described with reference to a fusion down draw process, it is to be understood that such embodiments are also applicable to other glass forming processes, such as float processes, slot draw processes, up-draw processes, tube drawing processes, and press-rolling processes.

[0060] It will be apparent to those skilled in the art that various modifications and variations can be made to embodiment of the present disclosure without departing from the spirit and scope of the disclosure. Thus it is intended that the present disclosure cover such modifications and variations provided they come within the scope of the appended claims and their equivalents.