US20190030683A1 - Damped abrasive article - Google Patents
Damped abrasive article Download PDFInfo
- Publication number
- US20190030683A1 US20190030683A1 US16/078,666 US201716078666A US2019030683A1 US 20190030683 A1 US20190030683 A1 US 20190030683A1 US 201716078666 A US201716078666 A US 201716078666A US 2019030683 A1 US2019030683 A1 US 2019030683A1
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- US
- United States
- Prior art keywords
- damping body
- abrasive
- abrasive article
- annular
- storage modulus
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
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Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24D—TOOLS FOR GRINDING, BUFFING OR SHARPENING
- B24D7/00—Bonded abrasive wheels, or wheels with inserted abrasive blocks, designed for acting otherwise than only by their periphery, e.g. by the front face; Bushings or mountings therefor
- B24D7/06—Bonded abrasive wheels, or wheels with inserted abrasive blocks, designed for acting otherwise than only by their periphery, e.g. by the front face; Bushings or mountings therefor with inserted abrasive blocks, e.g. segmental
- B24D7/066—Grinding blocks; their mountings or supports
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
- B24B41/00—Component parts such as frames, beds, carriages, headstocks
- B24B41/007—Weight compensation; Temperature compensation; Vibration damping
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24D—TOOLS FOR GRINDING, BUFFING OR SHARPENING
- B24D3/00—Physical features of abrasive bodies, or sheets, e.g. abrasive surfaces of special nature; Abrasive bodies or sheets characterised by their constituents
- B24D3/001—Physical features of abrasive bodies, or sheets, e.g. abrasive surfaces of special nature; Abrasive bodies or sheets characterised by their constituents the constituent being used as supporting member
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24D—TOOLS FOR GRINDING, BUFFING OR SHARPENING
- B24D5/00—Bonded abrasive wheels, or wheels with inserted abrasive blocks, designed for acting only by their periphery; Bushings or mountings therefor
- B24D5/06—Bonded abrasive wheels, or wheels with inserted abrasive blocks, designed for acting only by their periphery; Bushings or mountings therefor with inserted abrasive blocks, e.g. segmental
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24D—TOOLS FOR GRINDING, BUFFING OR SHARPENING
- B24D5/00—Bonded abrasive wheels, or wheels with inserted abrasive blocks, designed for acting only by their periphery; Bushings or mountings therefor
- B24D5/16—Bushings; Mountings
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24D—TOOLS FOR GRINDING, BUFFING OR SHARPENING
- B24D7/00—Bonded abrasive wheels, or wheels with inserted abrasive blocks, designed for acting otherwise than only by their periphery, e.g. by the front face; Bushings or mountings therefor
- B24D7/16—Bushings; Mountings
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24D—TOOLS FOR GRINDING, BUFFING OR SHARPENING
- B24D7/00—Bonded abrasive wheels, or wheels with inserted abrasive blocks, designed for acting otherwise than only by their periphery, e.g. by the front face; Bushings or mountings therefor
- B24D7/18—Wheels of special form
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
- B24B19/00—Single-purpose machines or devices for particular grinding operations not covered by any other main group
- B24B19/009—Single-purpose machines or devices for particular grinding operations not covered by any other main group for grinding profiled workpieces using a profiled grinding tool
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
- B24B9/00—Machines or devices designed for grinding edges or bevels on work or for removing burrs; Accessories therefor
- B24B9/02—Machines or devices designed for grinding edges or bevels on work or for removing burrs; Accessories therefor characterised by a special design with respect to properties of materials specific to articles to be ground
- B24B9/06—Machines or devices designed for grinding edges or bevels on work or for removing burrs; Accessories therefor characterised by a special design with respect to properties of materials specific to articles to be ground of non-metallic inorganic material, e.g. stone, ceramics, porcelain
- B24B9/08—Machines or devices designed for grinding edges or bevels on work or for removing burrs; Accessories therefor characterised by a special design with respect to properties of materials specific to articles to be ground of non-metallic inorganic material, e.g. stone, ceramics, porcelain of glass
Definitions
- the present disclosure relates generally to abrasive articles and, more particularly, to abrasive cutters and grinding wheels for brittle materials such as glass, ceramics, glass-ceramics and the like.
- Brittle materials such as glass, ceramic, glass-ceramic are sensitive to chips, cracks, or micro-cracks generated during the machining process. These chips and cracks can reduce the lifetime of the produced part or reduce its mechanical properties such as fatigue strength and flexural strength. Thermal properties are also affected and can lead to rejection of the machined part.
- the maximum acceptable size of the chips or micro-cracks which drives their propagation behavior between grain boundaries when exiting or through the solid material, is linked with the structure of the material and the balance of forces applied on the part; it can be calculated using the Griffith law and the Weibull distribution.
- chips and cracks may be generated due to the pressure applied on the machined part when removing material.
- the chips and micro-cracks are due to the contact force between the working abrasive diamonds and the brittle material. The contact force is needed to penetrate the abrasive diamonds into the material and the relative movement between the diamonds on the tool and the material removes the required material from the workpiece. If there is vibration between the diamonds and the brittle material during the machining process, each diamond acts as a hammer and can generate chips and micro-cracks at the surface of the material or inside it.
- US Patent Publication 2002/0004362 discloses a countersink bit for glass that has a shaft extending along and rotatable about an axis, a head fixed to the shaft and having a frustoconical surface centered on the axis, a layer of grinding material on the surface, and an axially relatively incompressible plastic body capable of transmitting torque between the surface and the shaft.
- the plastic body has good damping capabilities so that any tendency of the head to vibrate or chatter is largely eliminated.
- abrasive articles for brittle materials. More particularly, it would be desirable to provide a grinding wheel for brittle materials, such as glass, ceramics, glass-ceramics and the like, that has improved durability and produces fewer and/or smaller chips, cracks, or micro-cracks in the brittle material during the machining process.
- damping body formed from a synthetic polymer between a machine attaching end and an abrasive surface in a damped grinding wheel.
- the synthetic polymer is selected to have a specific modulus range and loss factor when tested under dynamic cyclic cycling.
- the range for these properties that achieves the purpose is a Storage Modulus of the damped body of from 1000 MPa to 2500 MPa and a Loss Factor from 0.025 to 0.10 at 25° C. and 10 Hz.
- the invention resides in a damped abrasive article comprising an abrasive surface comprising abrasive particles and a damping body connected with the abrasive surface; wherein the damping body comprises a synthetic polymer having a Storage Modulus from 1000 MPa to 2500 MPa and a Loss Factor from 0.025 to 0.10 at 25° C. and 10 Hz.
- FIGS. 1 and 1A illustrate a damped abrasive article according to one embodiment.
- FIGS. 2 and 2A illustrate a damped abrasive article according to another embodiment.
- FIGS. 3 and 3A illustrate a damped abrasive article according to another embodiment.
- FIGS. 4 and 4A illustrate a damped abrasive article according to another embodiment.
- FIGS. 5 and 5A illustrate a damped abrasive article according to another embodiment.
- FIGS. 6 and 6A illustrate a damped abrasive article according to another embodiment.
- FIGS. 7 and 7A illustrate a damped abrasive article according to another embodiment.
- FIGS. 8 and 8A illustrate a damped abrasive article according to another embodiment.
- FIGS. 1 and 1A a damped abrasive article 10 in the form of a cutter is shown. More particularly, FIGS. 1 and 1A show an abrasive article 10 in the form of a grinding wheel 40 suited for grinding bio-ceramic prosthesis.
- the damped abrasive article 10 includes a machine attaching end 12 , a damping body 14 , and an abrasive cutting surface 16 .
- the machine attaching end 12 is configured to transmit driving torque and linear force from a suitable machine (not shown) to rotate and translate the damped abrasive article 10 relative to a work piece when machining or removing material from the work piece.
- the machine attaching end 12 may comprise a round, square, hexagonal, or polygonal shaft, a tapered shaft and collet, a threaded shaft, a round shaft with flats for the jaws of a chuck, or other suitable mechanical structure to transmit the required torque and linear force.
- the machine attaching end 12 include a first end attachment portion 12 a for attachment with the machine, a tapered middle portion 12 b , and a cylindrical portion 12 c attached with the damping body 14 .
- the first end portion 12 a can utilize external or internal threads depending on the configuration of the spindle of the machine used to rotate and translate the damped abrasive article 10 .
- the first end portion 12 a includes wrench flats 24 or a hole for use with an open-end wrench for installing and removing the first end portion 12 a when replacing the damped abrasive article 10 .
- the machine attaching end 12 is made from a metal material, such as steel or stainless steel, for use with cooling or cutting fluids during the machining operation.
- a metal material such as steel or stainless steel
- suitable metals such as rigid plastics or the material selected for the damping body 14 , can be utilized for the machine attaching end 12 .
- an optional longitudinal bore 26 can be provided through the machine attaching end 12 and through the damping body 14 to supply cooling fluid to the abrasive cutting surface 16 .
- the size of the bore can be selected based on the flow of coolant required.
- the abrasive cutting surface 16 can comprise a hollow cylinder 28 with a recessed bore 30 that mates with the damping body 14 having cylindrical projection 32 extending from a shoulder 34 .
- FIGS. 2 and 2A show a grinding wheel 40 suited for fletting tableware glass.
- the grinding wheel 40 includes an annular damping body 14 and an annular cutting surface 16 .
- the annular damping body 14 contains a central opening 42 , opposed first and second major surfaces 44 , 46 , and an outer circumferential edge surface 48 .
- the annular cutting surface 16 includes a beveled edge 16 a adjacent the circumferential edge surface 48 .
- the annular abrasive cutting surface 16 is provided on an outer annular region of the damping body 14 second major surface 46 adjacent the outer circumferential edge surface 48 of the damping body.
- the abrasive cutting surface 16 is not provided on an inner annular region of the damping body 16 second major surface 46 . It will be recognized, however, that the abrasive cutting surface 16 can be provided on the entirety of the damping body 16 second major surface. In other embodiments, the abrasive cutting surface 16 may be conterminous with the second major surface of the damping body 14 , or the cutting surface 16 may be provided in the form of segments or patterns to cover selected regions of the second major surface 46 of the damping body 14 . In one embodiment, the abrasive cutting surface 16 is a metal bonded diamond layer glued directly to a polyamide glass fiber reinforced damping body 14 . In the illustrated embodiment, the damping body 14 is generally thin and flat and has a uniform thickness. More particularly, the first and second major surface 42 , 44 are co-planar.
- FIGS. 3 and 3A show a grinding wheel 40 suited for machining construction glass.
- the grinding wheel 40 includes an annular damping body 14 , an annular cutting surface 16 , and an optional annular reinforcing plate 50 arranged between the damping body 14 and the cutting surface 16 .
- the reinforcing plate 50 can be made of metal or filled resin material like filled phenolic resin.
- the annular damping body 14 contains a central opening 42 , and has opposed first and second major surfaces 44 , 46 and an outer circumferential edge surface 48 .
- the annular reinforcing plate 50 is provided along an outer annular region of the damping body 14 second major surface 46 adjacent the outer circumferential edge surface 48 , and the annular abrasive cutting surface 16 is provided on an outer annular region of the reinforcing plate 50 .
- the outer diameters of the damping body 14 , the cutting surface 16 and the reinforcing plate 50 are equal and the outer surfaces of the damping body 14 , the cutting surface 16 and the reinforcing plate 50 contiguous.
- the grinding wheel 40 further includes an optional annular race or central reinforcing hub 62 provided along the inner annular surface defining the central opening 42 .
- the reinforcing hub 62 enhances the strength of the damping body 14 in the region adjacent the central opening 42 of the grinding wheel 40 , and thereby improves the performance and durability of the grinding wheel 40 .
- the reinforcing hub 62 may be secured directly to the damping body 14 by, of example, molding the reinforcing hub 62 and damping body 14 together, or by pressing the reinforcing hub 62 into the damping body 14 , or the reinforcing hub 62 may be secured to the damping body 14 by fastening or bonding the reinforcing hub 62 to the damping body 14 using, for example, mechanical fasteners or adhesives.
- the inner diameter of the abrasive cutting surface 16 is greater than the inner diameter of the reinforcing plate 50 , whereby the radial dimension (i.e. the thickness in the radial dimension) of the cutting surface 16 is less than and the radial dimension of the reinforcing plate, and the cutting surface 16 does not cover an inner annular portion of the reinforcing plate 50 .
- the inner diameter of the reinforcing plate 50 is greater than the inner diameter of the damping body 14 , whereby the radial dimension of the reinforcing plate is less than the radial dimension of the damping body 14 and the reinforcing plate 50 does not cover an inner annular portion of the damping body 14 . It will be recognized, however, that the inner and outer diameters of the damping body 14 , the cutting surface 16 and the reinforcing plate 50 can be varied depending on the overall construction and intended end-use application for the grinding wheel 40 .
- FIGS. 4 and 4A show a grinding wheel 40 similar to the grinding wheel depicted in FIGS. 3 and 3A except the optional reinforcing plate 50 in FIGS. 3 and 3A has been eliminated, the annular damping body 14 includes an annular shoulder portion 14 a , the annular abrasive cutting surface 16 is contiguous with the damping body 14 annular shoulder portion 14 a , and the annular central reinforcing hub 62 has been enlarged to extend from the central opening 42 to the outer circumferential surface 48 .
- FIGS. 5 and 5A show a grinding wheel 40 suited for flute grinding operations on drills or milling tools.
- the grinding wheel 40 includes an annular damping body 14 , an annular cutting surface 16 , and an optional annular central reinforcing hub or plate 50 .
- the annular damping body 14 contains a central opening 42 , opposed first and second major surfaces 44 , 46 , and an outer circumferential edge surface 48 .
- the outer circumferential edge surface 48 is beveled and flares radially outwardly in the direction from the first major surface 44 to the second major surface 46 .
- the beveled edge surface 48 includes an outer annular recess 52 remote from the central reinforcing hub 62 configured to receive the annular cutting surface 16 , whereby the annular abrasive cutting surface 16 is provided along the beveled edge surface 48 .
- the damping body 14 further includes an inner annular recess 54 adjacent the central opening 42 configured to receive the reinforcing hub 62 .
- the grinding wheel 40 includes an annular damping body 14 , an annular abrasive cutting surface 16 , and an optional annular central hub 62 .
- the annular damping body 14 includes opposed first and second major surfaces 44 , 46 , an outer circumferential edge surface 48 .
- the annular damping body 14 contains a central opening 42 and a plurality of axial through bores 56 .
- the annular damping body 14 further contains an annular recess or channel 58 adjacent the outer circumferential edge surface 48 adapted to receive the annular abrasive cutting surface 16 .
- the annular damping body 14 includes a pair of shoulder portions 14 a that extend along each side of the abrasive cutting surface 16 .
- the abrasive cutting surface 16 contains an annular groove 60 .
- FIGS. 7 and 7A show a grinding wheel 40 similar to the grinding wheel shown in FIGS. 6 and 6A except one of the shoulder portions 14 a has been eliminated and replaced with an annular reinforcing plate 50 .
- the reinforcing plate 50 may formed of an electrically conductive metal material, such as steel, and may be provided with an electrical connection to enable profiling by an electro-erosion process.
- An electro-erosion process may be used to profile or shape a grinding wheel in which the abrasive incorporated is diamond, cubic boron nitride or similar hard material. The electro-erosion process is able to achieve the required profile precision.
- the grinding wheel 40 include an annular damping body 14 and an annular abrasive cutting surface 16 .
- the annular damping body 14 includes opposed first and second major surfaces 44 , 46 , an outer circumferential edge surface 48 .
- the annular damping body 14 contains a central opening 42 and a plurality of axial bores 56 .
- the annular damping body 14 further contains an annular recess or channel 58 adjacent the outer circumferential edge surface 48 adapted to receive the annular abrasive cutting surface 16 .
- the annular damping body 14 includes a shoulder portion 14 a that extends along the second major surface 46 adjacent the abrasive cutting surface 16 .
- the abrasive cutting surface 16 contains an annular groove 60 .
- the grinding wheel 40 further includes an annular reinforcing plate 50 arranged along, and contiguous with, the first major surface 44 of the annular damping body 14 .
- the reinforcing plate 50 may formed of an electrically conductive metal material, such as steel, and may be provided with an electrical connection to enable profiling by an electro-erosion process.
- the damping body 14 is made of a synthetic polymer.
- the polymer can be a thermoplastic, and selected from, for example, polyethylene, polypropylene, polyester, polyamide, polyvinyl, polyetherimide, polydimethylsiloxane or polyetheretherketone for thermoplastic families.
- the synthetic polymer can be reinforced or blended with a filler.
- Suitable fillers can be fibers or tubes such as carbon fibers or nanotubes, glass fibers, mineral fibers, ceramic fibers, metal fibers or aramid fibers; it can be whiskers such as silicon carbide whiskers or powder such as silicon carbide powder, aluminum oxide powder or metal powder such as aluminum powder, copper powder. Suitable fillers can also include mixtures of those components.
- a quantity of an anti-wearing agent can be added into the mixture in order to reduce the possible wear of the synthetic polymer body during the drilling and/or chamfering operation when abrasive material is machined.
- Suitable anti-wearing agents include molybdenum disulfide, graphite or PTFE
- the damping body 14 is made from polyamide 6 reinforced with glass fibers.
- glass fibers are used as a reinforcing material at a level from 1 percent to 50 percent, or from 10 percent to 50 percent, or from 30 percent to 50 percent by weight of the polyamide 6 mixture.
- a 30 percent glass fiber reinforced polyamide 6 mixture is commercially marketed by Ensinger GmbH under the tradename TECAMID 6 GF30 Black. This material was tested for the Storage Modulus and Loss Factor as described below and found to have a Storage Modulus of 1943 MPa and a Loss Factor of 0.033 at 25° C. and 10 Hz.
- Dynamic mechanical analysis and sample preparation were performed according to the ASTM D4065-12 standard and the procedures mentioned therein. Dynamic mechanical measurements were performed on a DMTA V (Rheometric Scientific) in single cantilever mode in a frequency range from 0.1 to 10 Hz and fixed strain of 0.05% at a temperature of 25° C. to 45° C. Specimens of rectangular shape measuring 20 ⁇ 5 ⁇ 4 mm are used. The temperature calibration was done using a Fluke 724 Temperature Calibrator, which is regularly calibrated by an accredited calibration institute. PVC standards (available through RHEO Service) were measured on the DMTA periodically to check temperature accuracy. The Storage Modulus and Lost Factor values are obtained at 25° C., 35° C., and 45° C. and at 10 Hz.
- the Storage Modulus of the material forming the damped body is from 1000 MPa to 2500 MPa, or from 1000 MPa to 2000 MPa, or from 1200 MPa to 2000 MPa at 25° C. and 10 Hz.
- the Loss Factor of the material forming the damped body is from 0.025 to 0.10, or from 0.03 to 0.10, or from 0.03 to 0.09 at 25° C. and 10 Hz.
- the Storage Modulus at 45° C. and 10 Hz (1303 Mpa) is lower than the Storage Modulus at 25° C.
- the prior art thermoset glass filled phenolic had a Storage Modulus that increased as the temperature of the test was increased whereas the Storage Modulus of the polyamide 6 glass fiber mix decreased as the temperature of the test was increased.
- the Storage Modulus and Loss Factor are determined in accordance with ASTM D4065 and the test parameters described above.
- the length of the damping body along the longitudinal axis of the abrasive article is preferably from 3 mm to about 60 mm although lengths outside of this range may be used as well. If the length becomes too small insufficient damping may occur, and if the length becomes too great excessive twisting or flexing of the abrasive article may occur during use. In order to reduce such twisting or flexing, a reinforcing plate 50 may be provided on the side of the grinding wheel or in the bore of the grinding wheel.
- the abrasive cutting surface 16 may be provided as, for example, a cutting member affixed to the damping body 14 or as a thin abrasive surface coated onto the damping body 14 .
- the abrasive cutting surface 16 may be provided as a member, such as an annular member, having a continuous surface, or the abrasive cutting surface 16 may be provided in the form of separate (i.e. individual) segments that define a discontinuous surface.
- the abrasive cutting member may be affixed to the damping body 14 using mechanical fastening means or bonded to the damping body 14 using, for example, glue or adhesive.
- the abrasive cutting surface 16 comprises an abrasive particle in a binder. Any suitable abrasive particle may be included in the abrasive cutting surface. Typically, the abrasive particles have a Mohs' hardness of at least 8, or even 9 and 10. Examples of such abrasive particles include aluminum oxide, fused aluminum oxide, ceramic aluminum oxide, white fused aluminum oxide, heat treated aluminum oxide, silica, silicon carbide, green silicon carbide, alumina zirconia, diamond, iron oxide, ceria, cubic boron nitride, garnet, tripoli, alpha alumina sol-gel derived abrasive particles, and combinations thereof.
- the abrasive particles have an average particle size of less than or equal to 1500 micrometers, although average particle sizes outside of this range may also be used.
- useful abrasive particle sizes typically range from an average particle size in a range of from at least 0.01, 1, 3 or even 5 micrometers up to and including 35, 100, 250, 500, or even as much as 1500 micrometers.
- diamond grits between 10 ⁇ m and 300 ⁇ m are used.
- the abrasive cutting surface is generally made by a molding process.
- a binder precursor either liquid organic, powdered inorganic, powdered organic, or a combination of thereof, could be mixed or not with the abrasive particles.
- a liquid medium either resin or a solvent
- the abrasive cutting surface according to the present disclosure may be made by compression molding, injection molding, transfer molding, or the like. The molding can be done either by hot or cold pressing or any suitable manner known to those skilled in the art.
- the binder typically comprises a glassy inorganic material (e.g., as in the case of vitrified abrasive wheels), metal, or an organic resin (e.g., as in the case of resin-bonded abrasive wheels).
- a glassy inorganic material e.g., as in the case of vitrified abrasive wheels
- metal e.g., as in the case of vitrified abrasive wheels
- organic resin e.g., as in the case of resin-bonded abrasive wheels
- Glassy inorganic binders may be made from a mixture of different metal oxides.
- these metal oxide vitreous binders include silica, alumina, calcia, iron oxide, titania, magnesia, sodium oxide, potassium oxide, lithium oxide, manganese oxide, boron oxide, phosphorous oxide, and the like.
- the vitreous binder in a powder form, may be mixed with a temporary binder, typically an organic binder.
- the vitrified binders may also be formed from a frit, for example anywhere from about one to 100 percent frit, but generally 20 to 100 percent frit.
- frit binders Some examples of common materials used in frit binders include feldspar, borax, quartz, soda ash, zinc oxide, whiting, antimony trioxide, titanium dioxide, sodium silicofluoride, flint, cryolite, boric acid, and combinations thereof. These materials are usually mixed together as powders, fired to fuse the mixture and then the fused mixture is cooled. The cooled mixture is crushed and screened to a very fine powder to then be used as a frit binder. The temperature at which these frit bonds are matured is dependent upon its chemistry, but may range from anywhere from about 600.deg. C. to about 1800.deg. C.
- the binder which holds the shape of the abrasive cutting surface, is typically included in an amount of from 5 to 50 percent, more typically 10 to 25, and even more typically 12 to 24 percent by weight, based on the total weight of the bonded abrasive wheel.
- metal binders examples include tin, copper, cobalt, bronze, aluminum, iron, cast iron, manganese, silver, titanium, carbon, chromium, nickel, and combinations thereof in prealloyed forms or not.
- Metal binders can include fillers such as silicon carbide, aluminum oxide, boron carbide, tungsten, tungsten carbide and combination thereof in prealloyed form or not.
- the metal binder in a powder form, may be mixed with a temporary binder, typically an inorganic binder.
- the metal binders may also be formed from a mix of pure and prealloyed powder or already pre-mix of metal powders and fillers. These materials are usually mixed together as powders, fired to sinter the mixture and then the sintered mixture is cooled. The temperature at which these metal bonds are matured is dependent upon the chemistry, but may range from anywhere from about 450° C. to about 1100° C.
- the binder which holds the shape of the abrasive cutting surface, is typically included in an amount of from 65 to 98 percent, more typically 75 to 96, and even more typically 88 to 96 percent by weight, based on the total weight of the bonded abrasive wheel.
- the binder may comprise a cured organic binder resin, filler, and grinding aids.
- Phenolic resin is the most commonly used organic binder resin, and may be used in both the powder form and liquid state. Although phenolic resins are widely used, it is within the scope of this disclosure to use other organic binder resins including, for example, epoxy resins, polyimide resins, polyamide-imide resins, polyetherimide resins, polyetherketone resins, polyetheretherketone resins, polyethersulfone resins, polyester resins, urea-formaldehyde resins, rubbers, shellacs, and acrylic binders.
- the organic binder may also be modified with other binders to improve or alter the properties of the binder.
- the amount of organic binder resin can be, for example, from 15 to 100 percent by weight of the total weight of the binder.
- Useful phenolic resins include novolac and resole phenolic resins.
- Novolac phenolic resins are characterized by being acid-catalyzed and having a ratio of formaldehyde to phenol of less than one, typically between 0.5:1 and 0.8:1.
- Resole phenolic resins are characterized by being alkaline catalyzed and having a ratio of formaldehyde to phenol of greater than or equal to one, typically from 1:1 to 3:1.
- Novolac and resole phenolic resins may be chemically modified (e.g., by reaction with epoxy compounds), or they may be unmodified.
- Exemplary acidic catalysts suitable for curing phenolic resins include sulfuric, hydrochloric, phosphoric, oxalic, and p-toluenesulfonic acids.
- Alkaline catalysts suitable for curing phenolic resins include sodium hydroxide, barium hydroxide, potassium hydroxide, calcium hydroxide, organic amines, or sodium carbonate.
- Phenolic resins are well-known and readily available from commercial sources.
- Examples of commercially available novolac resins include DUREZ 1364, a two-step, powdered phenolic resin (marketed by Durez Corporation of Addison, Tex., under the trade designation VARCUM (e.g., 29302), or HEXION AD5534 RESIN (marketed by Hexion Specialty Chemicals, Inc. of Louisville, Ky.).
- VARCUM e.g., 29302
- HEXION AD5534 RESIN marketed by Hexion Specialty Chemicals, Inc. of Louisville, Ky.
- Examples of commercially available resole phenolic resins useful in practice of the present disclosure include those marketed by Durez Corporation under the trade designation VARCUM (e.g., 29217, 29306, 29318, 29338, 29353); those marketed by Ashland Chemical Co. of Bartow, Fla.
- AEROFENE e.g., AEROFENE 295
- PHENOLITE e.g., PHENOLITE TD-2207
- the abrasive cutting surface is affixed to the damping body by an adhesive.
- Suitable industrial adhesives can be used such as an epoxy product sold under the tradename 3MTM Scotch-WeldTM Epoxy Adhesive DP460.
- the abrasive cutting surface can be fixed to one or more intermediate materials with sufficient strength to transmit the torque from the damping body to the abrasive cutting surface without slipping.
- a diamond metal bonded abrasive article as shown in FIG. 7 was made to grind the profile of an automotive front windshield in 2.1 mm thick glass.
- the abrasive article had a damping body made from polyamide 6 reinforced with 30% glass fibers by weight.
- the polyamide 6 glass fiber mix is commercially marketed by Ensinger GmbH under the tradename TECAMID 6 GF30 Black. This material was tested for the Storage Modulus and Loss Factor as described and found to have a Storage Modulus of 1943 MPa and a Loss Factor of 0.033 at 25° C. and 10 Hz.
- the abrasive article was operated at xx rpm at a feed rate of xx m/min on a Bystronic machine, dressing every xx pieces and cooled with water slightly emulsified with a lubricant additive.
- a diamond metal bonded abrasive article as shown in FIG. 7 was tested to grind the profile of an automotive front windshield in 2.1 mm thick glass.
- the abrasive article had a central body made of steel.
- the abrasive article was operated at 5,100 rpm at a feed rate of 14 m/min, having a material removal of 0.5 mm and dressing every 15 pieces and cooled with water slightly emulsified with a lubricant additive.
- the abrasive article had a lifetime number of 57112 ground meters including 5 re-profiling.
- the quality measurement was estimated having a GQM of 30.
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Abstract
Description
- The present disclosure relates generally to abrasive articles and, more particularly, to abrasive cutters and grinding wheels for brittle materials such as glass, ceramics, glass-ceramics and the like.
- Brittle materials such as glass, ceramic, glass-ceramic are sensitive to chips, cracks, or micro-cracks generated during the machining process. These chips and cracks can reduce the lifetime of the produced part or reduce its mechanical properties such as fatigue strength and flexural strength. Thermal properties are also affected and can lead to rejection of the machined part. The maximum acceptable size of the chips or micro-cracks, which drives their propagation behavior between grain boundaries when exiting or through the solid material, is linked with the structure of the material and the balance of forces applied on the part; it can be calculated using the Griffith law and the Weibull distribution.
- During the machining process of brittle materials like glass, ceramic, glass-ceramic and similar materials, chips and cracks may be generated due to the pressure applied on the machined part when removing material. The chips and micro-cracks are due to the contact force between the working abrasive diamonds and the brittle material. The contact force is needed to penetrate the abrasive diamonds into the material and the relative movement between the diamonds on the tool and the material removes the required material from the workpiece. If there is vibration between the diamonds and the brittle material during the machining process, each diamond acts as a hammer and can generate chips and micro-cracks at the surface of the material or inside it.
- Conventional techniques used to reduce the number and size of chips and micro-cracks include reducing the diamond grit size or grit quality, lowering the bond hardness, or modifying the machine parameters, such as, by reducing the infeed speed. These techniques, however, can negatively affect the productivity of the grinding process by increasing the time needed for the operation and by reducing the useful life of the tool.
- Abrasive articles for glass are known in the prior art. US Patent Publication 2002/0004362 (Lubke) discloses a countersink bit for glass that has a shaft extending along and rotatable about an axis, a head fixed to the shaft and having a frustoconical surface centered on the axis, a layer of grinding material on the surface, and an axially relatively incompressible plastic body capable of transmitting torque between the surface and the shaft. The plastic body has good damping capabilities so that any tendency of the head to vibrate or chatter is largely eliminated.
- The industry is always seeking improved abrasive articles for brittle materials. More particularly, it would be desirable to provide a grinding wheel for brittle materials, such as glass, ceramics, glass-ceramics and the like, that has improved durability and produces fewer and/or smaller chips, cracks, or micro-cracks in the brittle material during the machining process.
- It has been discovered that improved damping, and thereby a reduction in micro cracks and improved tool life, can be achieved by positioning a damping body formed from a synthetic polymer between a machine attaching end and an abrasive surface in a damped grinding wheel. In particular, the synthetic polymer is selected to have a specific modulus range and loss factor when tested under dynamic cyclic cycling. The range for these properties that achieves the purpose is a Storage Modulus of the damped body of from 1000 MPa to 2500 MPa and a Loss Factor from 0.025 to 0.10 at 25° C. and 10 Hz.
- Thus, in one embodiment the invention resides in a damped abrasive article comprising an abrasive surface comprising abrasive particles and a damping body connected with the abrasive surface; wherein the damping body comprises a synthetic polymer having a Storage Modulus from 1000 MPa to 2500 MPa and a Loss Factor from 0.025 to 0.10 at 25° C. and 10 Hz.
-
FIGS. 1 and 1A illustrate a damped abrasive article according to one embodiment. -
FIGS. 2 and 2A illustrate a damped abrasive article according to another embodiment. -
FIGS. 3 and 3A illustrate a damped abrasive article according to another embodiment. -
FIGS. 4 and 4A illustrate a damped abrasive article according to another embodiment. -
FIGS. 5 and 5A illustrate a damped abrasive article according to another embodiment. -
FIGS. 6 and 6A illustrate a damped abrasive article according to another embodiment. -
FIGS. 7 and 7A illustrate a damped abrasive article according to another embodiment. -
FIGS. 8 and 8A illustrate a damped abrasive article according to another embodiment. - Referring now to
FIGS. 1 and 1A , a dampedabrasive article 10 in the form of a cutter is shown. More particularly,FIGS. 1 and 1A show anabrasive article 10 in the form of agrinding wheel 40 suited for grinding bio-ceramic prosthesis. The dampedabrasive article 10 includes amachine attaching end 12, a dampingbody 14, and anabrasive cutting surface 16. Themachine attaching end 12 is configured to transmit driving torque and linear force from a suitable machine (not shown) to rotate and translate the dampedabrasive article 10 relative to a work piece when machining or removing material from the work piece. - The
machine attaching end 12 may comprise a round, square, hexagonal, or polygonal shaft, a tapered shaft and collet, a threaded shaft, a round shaft with flats for the jaws of a chuck, or other suitable mechanical structure to transmit the required torque and linear force. In the illustrated embodiment, themachine attaching end 12 include a firstend attachment portion 12 a for attachment with the machine, atapered middle portion 12 b, and acylindrical portion 12 c attached with thedamping body 14. Thefirst end portion 12 a can utilize external or internal threads depending on the configuration of the spindle of the machine used to rotate and translate the dampedabrasive article 10. In the illustrated embodiment, thefirst end portion 12 a includeswrench flats 24 or a hole for use with an open-end wrench for installing and removing thefirst end portion 12 a when replacing the dampedabrasive article 10. - Typically the
machine attaching end 12 is made from a metal material, such as steel or stainless steel, for use with cooling or cutting fluids during the machining operation. Other suitable metals, such as rigid plastics or the material selected for the dampingbody 14, can be utilized for themachine attaching end 12. - In order to cool the damped abrasive article during use, an optional
longitudinal bore 26 can be provided through themachine attaching end 12 and through the dampingbody 14 to supply cooling fluid to theabrasive cutting surface 16. The size of the bore can be selected based on the flow of coolant required. - Various mechanical interfaces can be used to connect the
abrasive cutting surface 16 and themachine attaching end 12 to the dampingbody 14. For example, theabrasive cutting surface 16 can comprise ahollow cylinder 28 with arecessed bore 30 that mates with thedamping body 14 havingcylindrical projection 32 extending from ashoulder 34. - Referring now to
FIGS. 2-8 , wherein like reference numerals refer to like or corresponding parts throughout the several views,FIGS. 2 and 2A show agrinding wheel 40 suited for fletting tableware glass. The grindingwheel 40 includes anannular damping body 14 and anannular cutting surface 16. Theannular damping body 14 contains acentral opening 42, opposed first and secondmajor surfaces circumferential edge surface 48. In the illustrated embodiment, theannular cutting surface 16 includes abeveled edge 16 a adjacent thecircumferential edge surface 48. The annularabrasive cutting surface 16 is provided on an outer annular region of thedamping body 14 secondmajor surface 46 adjacent the outercircumferential edge surface 48 of the damping body. In the illustrated embodiment, theabrasive cutting surface 16 is not provided on an inner annular region of the dampingbody 16 secondmajor surface 46. It will be recognized, however, that theabrasive cutting surface 16 can be provided on the entirety of the dampingbody 16 second major surface. In other embodiments, theabrasive cutting surface 16 may be conterminous with the second major surface of thedamping body 14, or thecutting surface 16 may be provided in the form of segments or patterns to cover selected regions of the secondmajor surface 46 of thedamping body 14. In one embodiment, theabrasive cutting surface 16 is a metal bonded diamond layer glued directly to a polyamide glass fiber reinforceddamping body 14. In the illustrated embodiment, the dampingbody 14 is generally thin and flat and has a uniform thickness. More particularly, the first and secondmajor surface -
FIGS. 3 and 3A show a grindingwheel 40 suited for machining construction glass. Thegrinding wheel 40 includes anannular damping body 14, anannular cutting surface 16, and an optionalannular reinforcing plate 50 arranged between thedamping body 14 and thecutting surface 16. The reinforcingplate 50 can be made of metal or filled resin material like filled phenolic resin. Theannular damping body 14 contains acentral opening 42, and has opposed first and secondmajor surfaces circumferential edge surface 48. Theannular reinforcing plate 50 is provided along an outer annular region of thedamping body 14 secondmajor surface 46 adjacent the outercircumferential edge surface 48, and the annularabrasive cutting surface 16 is provided on an outer annular region of the reinforcingplate 50. In the illustrated embodiment, the outer diameters of thedamping body 14, thecutting surface 16 and thereinforcing plate 50 are equal and the outer surfaces of thedamping body 14, thecutting surface 16 and the reinforcingplate 50 contiguous. In the illustrated embodiment, thegrinding wheel 40 further includes an optional annular race orcentral reinforcing hub 62 provided along the inner annular surface defining thecentral opening 42. The reinforcinghub 62 enhances the strength of the dampingbody 14 in the region adjacent thecentral opening 42 of thegrinding wheel 40, and thereby improves the performance and durability of thegrinding wheel 40. The reinforcinghub 62 may be secured directly to the dampingbody 14 by, of example, molding the reinforcinghub 62 and dampingbody 14 together, or by pressing the reinforcinghub 62 into the dampingbody 14, or the reinforcinghub 62 may be secured to the dampingbody 14 by fastening or bonding the reinforcinghub 62 to the dampingbody 14 using, for example, mechanical fasteners or adhesives. - In the illustrated embodiment, the inner diameter of the
abrasive cutting surface 16 is greater than the inner diameter of the reinforcingplate 50, whereby the radial dimension (i.e. the thickness in the radial dimension) of the cuttingsurface 16 is less than and the radial dimension of the reinforcing plate, and the cuttingsurface 16 does not cover an inner annular portion of the reinforcingplate 50. In addition, the inner diameter of the reinforcingplate 50 is greater than the inner diameter of the dampingbody 14, whereby the radial dimension of the reinforcing plate is less than the radial dimension of the dampingbody 14 and the reinforcingplate 50 does not cover an inner annular portion of the dampingbody 14. It will be recognized, however, that the inner and outer diameters of the dampingbody 14, the cuttingsurface 16 and the reinforcingplate 50 can be varied depending on the overall construction and intended end-use application for thegrinding wheel 40. -
FIGS. 4 and 4A show agrinding wheel 40 similar to the grinding wheel depicted inFIGS. 3 and 3A except the optional reinforcingplate 50 inFIGS. 3 and 3A has been eliminated, the annular dampingbody 14 includes anannular shoulder portion 14 a, the annularabrasive cutting surface 16 is contiguous with the dampingbody 14annular shoulder portion 14 a, and the annular central reinforcinghub 62 has been enlarged to extend from thecentral opening 42 to the outercircumferential surface 48. -
FIGS. 5 and 5A show agrinding wheel 40 suited for flute grinding operations on drills or milling tools. The grindingwheel 40 includes an annular dampingbody 14, anannular cutting surface 16, and an optional annular central reinforcing hub orplate 50. The annular dampingbody 14 contains acentral opening 42, opposed first and secondmajor surfaces circumferential edge surface 48. In the illustrated embodiment, the outercircumferential edge surface 48 is beveled and flares radially outwardly in the direction from the firstmajor surface 44 to the secondmajor surface 46. Thebeveled edge surface 48 includes an outerannular recess 52 remote from the central reinforcinghub 62 configured to receive theannular cutting surface 16, whereby the annularabrasive cutting surface 16 is provided along thebeveled edge surface 48. The dampingbody 14 further includes an innerannular recess 54 adjacent thecentral opening 42 configured to receive the reinforcinghub 62. - Referring now to
FIGS. 6 and 6A , there is shown agrinding wheel 40 suited for machining construction or automotive glass. The grindingwheel 40 includes an annular dampingbody 14, an annularabrasive cutting surface 16, and an optional annularcentral hub 62. The annular dampingbody 14 includes opposed first and secondmajor surfaces circumferential edge surface 48. The annular dampingbody 14 contains acentral opening 42 and a plurality of axial through bores 56. The annular dampingbody 14 further contains an annular recess orchannel 58 adjacent the outercircumferential edge surface 48 adapted to receive the annularabrasive cutting surface 16. The annular dampingbody 14 includes a pair ofshoulder portions 14 a that extend along each side of theabrasive cutting surface 16. In the illustrated embodiment, theabrasive cutting surface 16 contains anannular groove 60. -
FIGS. 7 and 7A show agrinding wheel 40 similar to the grinding wheel shown inFIGS. 6 and 6A except one of theshoulder portions 14 a has been eliminated and replaced with an annular reinforcingplate 50. The reinforcingplate 50 may formed of an electrically conductive metal material, such as steel, and may be provided with an electrical connection to enable profiling by an electro-erosion process. An electro-erosion process may be used to profile or shape a grinding wheel in which the abrasive incorporated is diamond, cubic boron nitride or similar hard material. The electro-erosion process is able to achieve the required profile precision. As based on fusion, vaporization and ejection of the material due to the energy given by electrical sparking between two electrodes (metal bonded grinding wheel and profiling electrode) placed in a dielectric bath, an electrical conductivity between the abrasive metal bonded layer and the machine is needed. - Referring now to
FIGS. 8 and 8A , there is shown another embodiment of agrinding wheel 40 suited for machining construction or automotive glass. The grindingwheel 40 include an annular dampingbody 14 and an annularabrasive cutting surface 16. The annular dampingbody 14 includes opposed first and secondmajor surfaces circumferential edge surface 48. The annular dampingbody 14 contains acentral opening 42 and a plurality ofaxial bores 56. The annular dampingbody 14 further contains an annular recess orchannel 58 adjacent the outercircumferential edge surface 48 adapted to receive the annularabrasive cutting surface 16. The annular dampingbody 14 includes ashoulder portion 14 a that extends along the secondmajor surface 46 adjacent theabrasive cutting surface 16. In the illustrated embodiment, theabrasive cutting surface 16 contains anannular groove 60. The grindingwheel 40 further includes an annular reinforcingplate 50 arranged along, and contiguous with, the firstmajor surface 44 of the annular dampingbody 14. As with the embodiment inFIGS. 7 and 7A , the reinforcingplate 50 may formed of an electrically conductive metal material, such as steel, and may be provided with an electrical connection to enable profiling by an electro-erosion process. - In any of the embodiments described herein, the damping
body 14 is made of a synthetic polymer. The polymer can be a thermoplastic, and selected from, for example, polyethylene, polypropylene, polyester, polyamide, polyvinyl, polyetherimide, polydimethylsiloxane or polyetheretherketone for thermoplastic families. For adjusting mechanical, electrical and thermal properties, the synthetic polymer can be reinforced or blended with a filler. Suitable fillers can be fibers or tubes such as carbon fibers or nanotubes, glass fibers, mineral fibers, ceramic fibers, metal fibers or aramid fibers; it can be whiskers such as silicon carbide whiskers or powder such as silicon carbide powder, aluminum oxide powder or metal powder such as aluminum powder, copper powder. Suitable fillers can also include mixtures of those components. - A quantity of an anti-wearing agent can be added into the mixture in order to reduce the possible wear of the synthetic polymer body during the drilling and/or chamfering operation when abrasive material is machined. Suitable anti-wearing agents include molybdenum disulfide, graphite or PTFE
- In one embodiment, the damping
body 14 is made from polyamide 6 reinforced with glass fibers. In one embodiment, glass fibers are used as a reinforcing material at a level from 1 percent to 50 percent, or from 10 percent to 50 percent, or from 30 percent to 50 percent by weight of the polyamide 6 mixture. A 30 percent glass fiber reinforced polyamide 6 mixture is commercially marketed by Ensinger GmbH under the tradename TECAMID 6 GF30 Black. This material was tested for the Storage Modulus and Loss Factor as described below and found to have a Storage Modulus of 1943 MPa and a Loss Factor of 0.033 at 25° C. and 10 Hz. - Similar mixtures of polyamide 6 with glass fibers are marketed by E.I. du Pont de Nemours—under the tradename DuPont™ Zytel® 73G30T NC010 or DuPont™ Zytel® 73G30T BK261, or by Rhodia SA under the tradename TECHNYL® C216 V30 BLACK Z/4. Other polyamide 6 producers like EMS-Grivory part of the EMS Group under the trade name Grilon® B provide suitable products.
- It has been determined that in order to further reduce and/or eliminate chips and micro cracks when using the damped
abrasive article 10, the Storage Modulus and the Loss factor of the synthetic polymer is important. These properties can be measured using ASTM D4065 Standard Practice for Plastics: Dynamic Mechanical Properties: Determination and Report of Procedures - Dynamic mechanical analysis and sample preparation were performed according to the ASTM D4065-12 standard and the procedures mentioned therein. Dynamic mechanical measurements were performed on a DMTA V (Rheometric Scientific) in single cantilever mode in a frequency range from 0.1 to 10 Hz and fixed strain of 0.05% at a temperature of 25° C. to 45° C. Specimens of rectangular shape measuring 20×5×4 mm are used. The temperature calibration was done using a Fluke 724 Temperature Calibrator, which is regularly calibrated by an accredited calibration institute. PVC standards (available through RHEO Service) were measured on the DMTA periodically to check temperature accuracy. The Storage Modulus and Lost Factor values are obtained at 25° C., 35° C., and 45° C. and at 10 Hz.
-
TABLE 1 Storage Modulus and Loss Factor (10 Hz) Storage Loss Loss Modulus Modulus Factor E′ E′ Tan Material Temp. Mpa Mpa Delta polyamide 6 glass fiber mix 25° C. 1943 64 0.033 (GF30) 35° C. 1575 128 0.081 45° C. 1303 106 0.082 thermoset glass filled phenolic 25° C. 2557 60 0.024 (x680) (Prior Art) 35° C. 3084 69 0.022 45° C. 3059 63 0.021 - As shown in the Examples, a significant reduction in defects during machining of brittle materials and an improved tool life was achieved when the Storage Modulus of the material forming the damped body is from 1000 MPa to 2500 MPa, or from 1000 MPa to 2000 MPa, or from 1200 MPa to 2000 MPa at 25° C. and 10 Hz. Additionally, for the improvements noted above, the Loss Factor of the material forming the damped body is from 0.025 to 0.10, or from 0.03 to 0.10, or from 0.03 to 0.09 at 25° C. and 10 Hz. As listed in Table 1, the Storage Modulus at 45° C. and 10 Hz (1303 Mpa) is lower than the Storage Modulus at 25° C. and 10 Hz (1943 Mpa) for the polyamide 6 glass fiber material used for the damped abrasive article in one embodiment. The prior art thermoset glass filled phenolic had a Storage Modulus that increased as the temperature of the test was increased whereas the Storage Modulus of the polyamide 6 glass fiber mix decreased as the temperature of the test was increased. The Storage Modulus and Loss Factor are determined in accordance with ASTM D4065 and the test parameters described above.
- Another factor in the design of the damped abrasive article is the shape and size of the damped
central body 14. In general, the length of the damping body along the longitudinal axis of the abrasive article is preferably from 3 mm to about 60 mm although lengths outside of this range may be used as well. If the length becomes too small insufficient damping may occur, and if the length becomes too great excessive twisting or flexing of the abrasive article may occur during use. In order to reduce such twisting or flexing, a reinforcingplate 50 may be provided on the side of the grinding wheel or in the bore of the grinding wheel. - In any of the embodiments described herein, the
abrasive cutting surface 16 may be provided as, for example, a cutting member affixed to the dampingbody 14 or as a thin abrasive surface coated onto the dampingbody 14. In addition, theabrasive cutting surface 16 may be provided as a member, such as an annular member, having a continuous surface, or theabrasive cutting surface 16 may be provided in the form of separate (i.e. individual) segments that define a discontinuous surface. The abrasive cutting member may be affixed to the dampingbody 14 using mechanical fastening means or bonded to the dampingbody 14 using, for example, glue or adhesive. In some embodiments, theabrasive cutting surface 16 comprises an abrasive particle in a binder. Any suitable abrasive particle may be included in the abrasive cutting surface. Typically, the abrasive particles have a Mohs' hardness of at least 8, or even 9 and 10. Examples of such abrasive particles include aluminum oxide, fused aluminum oxide, ceramic aluminum oxide, white fused aluminum oxide, heat treated aluminum oxide, silica, silicon carbide, green silicon carbide, alumina zirconia, diamond, iron oxide, ceria, cubic boron nitride, garnet, tripoli, alpha alumina sol-gel derived abrasive particles, and combinations thereof. - Typically, the abrasive particles have an average particle size of less than or equal to 1500 micrometers, although average particle sizes outside of this range may also be used. For grinding operations, useful abrasive particle sizes typically range from an average particle size in a range of from at least 0.01, 1, 3 or even 5 micrometers up to and including 35, 100, 250, 500, or even as much as 1500 micrometers. In specific embodiments diamond grits between 10 μm and 300 μm are used.
- The abrasive cutting surface is generally made by a molding process. During molding, a binder precursor, either liquid organic, powdered inorganic, powdered organic, or a combination of thereof, could be mixed or not with the abrasive particles. In some instances, a liquid medium (either resin or a solvent) is first applied to the abrasive particles to wet their outer surface, and then the wetted particles are mixed with a powdered medium. The abrasive cutting surface according to the present disclosure may be made by compression molding, injection molding, transfer molding, or the like. The molding can be done either by hot or cold pressing or any suitable manner known to those skilled in the art.
- The binder typically comprises a glassy inorganic material (e.g., as in the case of vitrified abrasive wheels), metal, or an organic resin (e.g., as in the case of resin-bonded abrasive wheels).
- Glassy inorganic binders may be made from a mixture of different metal oxides. Examples of these metal oxide vitreous binders include silica, alumina, calcia, iron oxide, titania, magnesia, sodium oxide, potassium oxide, lithium oxide, manganese oxide, boron oxide, phosphorous oxide, and the like. During manufacture of a vitreous abrasive cutting surface, the vitreous binder, in a powder form, may be mixed with a temporary binder, typically an organic binder. The vitrified binders may also be formed from a frit, for example anywhere from about one to 100 percent frit, but generally 20 to 100 percent frit. Some examples of common materials used in frit binders include feldspar, borax, quartz, soda ash, zinc oxide, whiting, antimony trioxide, titanium dioxide, sodium silicofluoride, flint, cryolite, boric acid, and combinations thereof. These materials are usually mixed together as powders, fired to fuse the mixture and then the fused mixture is cooled. The cooled mixture is crushed and screened to a very fine powder to then be used as a frit binder. The temperature at which these frit bonds are matured is dependent upon its chemistry, but may range from anywhere from about 600.deg. C. to about 1800.deg. C.
- The binder, which holds the shape of the abrasive cutting surface, is typically included in an amount of from 5 to 50 percent, more typically 10 to 25, and even more typically 12 to 24 percent by weight, based on the total weight of the bonded abrasive wheel.
- Examples of metal binders include tin, copper, cobalt, bronze, aluminum, iron, cast iron, manganese, silver, titanium, carbon, chromium, nickel, and combinations thereof in prealloyed forms or not. Metal binders can include fillers such as silicon carbide, aluminum oxide, boron carbide, tungsten, tungsten carbide and combination thereof in prealloyed form or not. During manufacture of a metal abrasive cutting surface, the metal binder, in a powder form, may be mixed with a temporary binder, typically an inorganic binder. The metal binders may also be formed from a mix of pure and prealloyed powder or already pre-mix of metal powders and fillers. These materials are usually mixed together as powders, fired to sinter the mixture and then the sintered mixture is cooled. The temperature at which these metal bonds are matured is dependent upon the chemistry, but may range from anywhere from about 450° C. to about 1100° C.
- The binder, which holds the shape of the abrasive cutting surface, is typically included in an amount of from 65 to 98 percent, more typically 75 to 96, and even more typically 88 to 96 percent by weight, based on the total weight of the bonded abrasive wheel.
- The binder may comprise a cured organic binder resin, filler, and grinding aids. Phenolic resin is the most commonly used organic binder resin, and may be used in both the powder form and liquid state. Although phenolic resins are widely used, it is within the scope of this disclosure to use other organic binder resins including, for example, epoxy resins, polyimide resins, polyamide-imide resins, polyetherimide resins, polyetherketone resins, polyetheretherketone resins, polyethersulfone resins, polyester resins, urea-formaldehyde resins, rubbers, shellacs, and acrylic binders. The organic binder may also be modified with other binders to improve or alter the properties of the binder. The amount of organic binder resin can be, for example, from 15 to 100 percent by weight of the total weight of the binder.
- Useful phenolic resins include novolac and resole phenolic resins. Novolac phenolic resins are characterized by being acid-catalyzed and having a ratio of formaldehyde to phenol of less than one, typically between 0.5:1 and 0.8:1. Resole phenolic resins are characterized by being alkaline catalyzed and having a ratio of formaldehyde to phenol of greater than or equal to one, typically from 1:1 to 3:1. Novolac and resole phenolic resins may be chemically modified (e.g., by reaction with epoxy compounds), or they may be unmodified. Exemplary acidic catalysts suitable for curing phenolic resins include sulfuric, hydrochloric, phosphoric, oxalic, and p-toluenesulfonic acids. Alkaline catalysts suitable for curing phenolic resins include sodium hydroxide, barium hydroxide, potassium hydroxide, calcium hydroxide, organic amines, or sodium carbonate.
- Phenolic resins are well-known and readily available from commercial sources. Examples of commercially available novolac resins include DUREZ 1364, a two-step, powdered phenolic resin (marketed by Durez Corporation of Addison, Tex., under the trade designation VARCUM (e.g., 29302), or HEXION AD5534 RESIN (marketed by Hexion Specialty Chemicals, Inc. of Louisville, Ky.). Examples of commercially available resole phenolic resins useful in practice of the present disclosure include those marketed by Durez Corporation under the trade designation VARCUM (e.g., 29217, 29306, 29318, 29338, 29353); those marketed by Ashland Chemical Co. of Bartow, Fla. under the trade designation AEROFENE (e.g., AEROFENE 295); and those marketed by Kangnam Chemical Company Ltd. of Seoul, South Korea under the trade designation “PHENOLITE” (e.g., PHENOLITE TD-2207).
- In some embodiments, the abrasive cutting surface is affixed to the damping body by an adhesive. Suitable industrial adhesives can be used such as an epoxy product sold under the tradename 3M™ Scotch-Weld™ Epoxy Adhesive DP460. In other embodiments, the abrasive cutting surface can be fixed to one or more intermediate materials with sufficient strength to transmit the torque from the damping body to the abrasive cutting surface without slipping.
- A diamond metal bonded abrasive article as shown in
FIG. 7 was made to grind the profile of an automotive front windshield in 2.1 mm thick glass. The abrasive article had a damping body made from polyamide 6 reinforced with 30% glass fibers by weight. The polyamide 6 glass fiber mix is commercially marketed by Ensinger GmbH under the tradename TECAMID 6 GF30 Black. This material was tested for the Storage Modulus and Loss Factor as described and found to have a Storage Modulus of 1943 MPa and a Loss Factor of 0.033 at 25° C. and 10 Hz. The abrasive article was operated at xx rpm at a feed rate of xx m/min on a Bystronic machine, dressing every xx pieces and cooled with water slightly emulsified with a lubricant additive. The abrasive article. Lifetime number of ground meters was xx.+GQM - A diamond metal bonded abrasive article as shown in
FIG. 7 was tested to grind the profile of an automotive front windshield in 2.1 mm thick glass. The abrasive article had a central body made of steel. The abrasive article was operated at 5,100 rpm at a feed rate of 14 m/min, having a material removal of 0.5 mm and dressing every 15 pieces and cooled with water slightly emulsified with a lubricant additive. The abrasive article had a lifetime number of 57112 ground meters including 5 re-profiling. The quality measurement was estimated having a GQM of 30.
Claims (12)
Priority Applications (1)
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US16/078,666 US20190030683A1 (en) | 2016-02-26 | 2017-02-21 | Damped abrasive article |
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US201662300476P | 2016-02-26 | 2016-02-26 | |
US16/078,666 US20190030683A1 (en) | 2016-02-26 | 2017-02-21 | Damped abrasive article |
PCT/US2017/018623 WO2017147035A1 (en) | 2016-02-26 | 2017-02-21 | Damped abrasive article |
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EP (1) | EP3419785A4 (en) |
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WO2020056378A1 (en) | 2018-09-14 | 2020-03-19 | Align Technology, Inc. | Hybrid 3d printing with photo-curable materials |
US11607777B2 (en) * | 2016-05-13 | 2023-03-21 | Tyrolit—Schleifmittelwerke Swarovski K.G. | Grinding wheel with a vibration-damping support body |
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IT201700110864A1 (en) * | 2017-10-04 | 2019-04-04 | Saidtools Srl | SHARPENING TOOL |
DE102018113613B3 (en) | 2018-06-07 | 2019-07-04 | SCHOTT Diamantwerkzeuge GmbH | Diamond tool and method of making a diamond tool |
KR102682515B1 (en) | 2018-10-19 | 2024-07-09 | 생-고뱅 어브레이시브즈, 인코포레이티드 | grinding wheel assembly |
CN112677060A (en) * | 2020-12-15 | 2021-04-20 | 珠海市巨海科技有限公司 | Resin binder superhard grinding wheel and manufacturing method thereof |
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US6251493B1 (en) * | 1996-04-08 | 2001-06-26 | 3M Innovative Properties Company | Vibration and shock attenuating articles and method of attenuating vibrations and shocks therewith |
DE10032036A1 (en) * | 2000-07-05 | 2002-01-17 | Wendt Gmbh | Countersink tool has neck and head, grinder coating joined to drive spindle, plastic intermediate piece, ducts for cooling fluid and axial feeder duct. |
US6849684B2 (en) * | 2000-10-20 | 2005-02-01 | E. I. Du Pont De Nemours And Company | Molded soft elastomer/hard polyester composition with noise damping properties |
US20030106602A1 (en) * | 2001-12-07 | 2003-06-12 | Hsich Henry S. | Multi-layer assembly for fluid handling and containment systems |
US20080026245A1 (en) * | 2006-07-25 | 2008-01-31 | Yuji Saga | Vibration damping material, structural laminates, and processes for making same |
KR20130132961A (en) * | 2010-12-27 | 2013-12-05 | 이 아이 듀폰 디 네모아 앤드 캄파니 | Noise damping compositions |
CN102794715B (en) * | 2012-08-03 | 2015-07-15 | 河南工业大学 | Fiber-reinforced grinding wheel substrate and preparation method thereof |
BR112016027187B1 (en) * | 2014-05-29 | 2022-04-12 | Saint-Gobain Abrasives, Inc. | Abrasive article with a core including a polymer material, abrasive wheel and their method of preparation |
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2017
- 2017-02-21 EP EP17757044.7A patent/EP3419785A4/en not_active Withdrawn
- 2017-02-21 US US16/078,666 patent/US20190030683A1/en not_active Abandoned
- 2017-02-21 WO PCT/US2017/018623 patent/WO2017147035A1/en active Application Filing
- 2017-02-21 CN CN201780013339.7A patent/CN108698196A/en active Pending
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US11607777B2 (en) * | 2016-05-13 | 2023-03-21 | Tyrolit—Schleifmittelwerke Swarovski K.G. | Grinding wheel with a vibration-damping support body |
WO2020056378A1 (en) | 2018-09-14 | 2020-03-19 | Align Technology, Inc. | Hybrid 3d printing with photo-curable materials |
Also Published As
Publication number | Publication date |
---|---|
WO2017147035A1 (en) | 2017-08-31 |
EP3419785A4 (en) | 2019-09-04 |
CN108698196A (en) | 2018-10-23 |
EP3419785A1 (en) | 2019-01-02 |
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