Classifications

• • 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
  • B24D3/34—Physical features of abrasive bodies, or sheets, e.g. abrasive surfaces of special nature; Abrasive bodies or sheets characterised by their constituents characterised by additives enhancing special physical properties, e.g. wear resistance, electric conductivity, self-cleaning properties
  • B24D3/342—Physical features of abrasive bodies, or sheets, e.g. abrasive surfaces of special nature; Abrasive bodies or sheets characterised by their constituents characterised by additives enhancing special physical properties, e.g. wear resistance, electric conductivity, self-cleaning properties incorporated in the bonding agent
  • B24D3/344—Physical features of abrasive bodies, or sheets, e.g. abrasive surfaces of special nature; Abrasive bodies or sheets characterised by their constituents characterised by additives enhancing special physical properties, e.g. wear resistance, electric conductivity, self-cleaning properties incorporated in the bonding agent the bonding agent being organic
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B24—GRINDING; POLISHING
  • B24D—TOOLS FOR GRINDING, BUFFING OR SHARPENING
  • B24D11/00—Constructional features of flexible abrasive materials; Special features in the manufacture of such materials
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B24—GRINDING; POLISHING
  • B24D—TOOLS FOR GRINDING, BUFFING OR SHARPENING
  • B24D11/00—Constructional features of flexible abrasive materials; Special features in the manufacture of such materials
  • B24D11/001—Manufacture of flexible abrasive materials
• • 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
  • B24D3/02—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 bonding agent
  • B24D3/20—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 bonding agent and being essentially organic
  • B24D3/28—Resins or natural or synthetic macromolecular compounds
• • 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
  • B24D3/34—Physical features of abrasive bodies, or sheets, e.g. abrasive surfaces of special nature; Abrasive bodies or sheets characterised by their constituents characterised by additives enhancing special physical properties, e.g. wear resistance, electric conductivity, self-cleaning properties

Definitions

• the particles of solidified, handleable binder 82 resulting from the curing step of the process are removed from the production tool 76 and collected in a hopper 84. Removal is preferably carried out by mechanical means, e.g., a water jet. It is preferred that any debris remaining in the production tool 76 be removed before any fresh binder precursor is introduced. Debris removal can be accomplished by a brush, an air jet, or any other conventional technique. Although not shown in FIG. 3, additional means can be used to aid in removing the particles of binder from the production tool 76.
• FIG. 7 illustrates another variation of an apparatus capable of carrying out the method of this invention.
• the knurled workpiece described above was used to make a production tooling. First the workpiece and a nip roll were installed below an extruder. The knurled workpiece was held at 60°C (140°F) and the nip roll at 21°C (70°F).
• R represents hydrogen, trifluoromethyl, or straight-chain or branched-chain alkyl group containing 1 to 4 carbon atoms, a represents an integer from 1 to 10, b represents an integer from I to 6,
• the conditions of the method should be set such that any heat generated in the curing zone does not adversely affect the production tool
• Ethylenically unsaturated compounds include both monomeric and polymeric compounds that contain atoms of carbon, hydrogen and oxygen, and optionally, nitrogen and the halogens Oxygen or nitrogen atoms or both are generally present in ether, ester, urethane, amide, and urea groups.
• Ethylenically unsaturated compounds preferably have a molecular weight of less than about 4,000 and are preferably esters resulting from the reaction of compounds containing aliphatic monohydroxy groups or aliphatic polyhydroxy groups and unsaturated carboxylic acids, such as acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid, maleic acid, and the like.
• vinyl ethers suitable for this invention include vinyl ether functionalized urethane oligomers, commercially available from Allied Signal under the trade designations "VE 4010”, “VE 4015”, “VE 2010”, “VE 2020”, and "VE 4020"
• the abrasive grits have a Mohs' hardness of at least about 8, more preferably above 9
• materials of such abrasive grits include fused aluminum oxide, ceramic aluminum oxide, white fused aluminum oxide, heat treated aluminum oxide, silica, silicon carbide, green silicon carbide, alumina zirconia, diamond, ceria, titanium diboride, boron carbide, cubic boron nitride, garnet, tripoli, and combinations thereof
• the ceramic aluminum oxide is preferably made according to a sol gel process, such as described in U.S.
• the ceramic abrasive grit comprises alpha alumina and, optionally, a metal oxide modifier, such as magnesia, zirconia, zinc oxide, nickel oxide, hafnia, yttria, silica, iron oxide, titania, lanthanum oxide, ceria, neodymium oxide, and combinations thereof
• the ceramic aluminum oxide may also optionally comprise a nucleating agent, such as alpha alumina, iron oxide, iron oxide precursor, titania, chromia, or combinations thereof
• the ceramic aluminum oxide may also have a shape, such as that described in U S Patent Nos 5,201 ,916 and 5,090,968
• the ceramic abrasive grits may also contain a surface coating
• the binder After the binder is removed from the production tool, either by direct or indirect means, it is then converted into particles In one mode of conversion, the binder is released fi om the pi oduction tool in the form of particles A given particle will have a shape that is essentially the shape of the portion of the cavity of the production tool in which the particle was at least partially cured
• An advantage of this mode is that the particles are already of the proper grade or of the proper particle size distribution for subsequent use, e g , incorporation into an abrasive article
• the abrasive particles In the conventional manner of making abrasive particles, e g , agglomerates, the abrasive particles have to be ciushed and then screened to obtain proper particle size distribution
• Patent No 5,417,726 One popular coated abrasive backing is a cloth backing
• the cloth is composed of yarns in the warp direction, i e , the machine direction and yarns in the fill direction, i e , the cross direction
• the cloth backing can be a woven backing, a stitchbonded backing, or a weft insertion backing
• woven constructions include sateen weaves of 4 over one weave of the warp yarns over the fill yarns, twill weave of 3 over one weave, plain weave of one over one weave and a drill weave of two over two weave
• the warp and fill yarns are not interwoven, but are oriented in two distinct directions from one another
• the warp yarns are laid on top of the fill yarns and secured to another by a stitch yarn or by an adhesive
• the yarns in the cloth backing can be natural, synthetic or combinations thereof Examples of natural yarns include cellulosic such as cotton, hemp, kapok, flax, sisal, jute,
• the material for bonding the abrasive material to a substrate or together comprises a cured resinous adhesive and optional additives
• resinous adhesives suitable for this invention include phenolic resins, aminoplast resins, urethane resins, epoxy resins, acrylate resins, aciylated isocyanurate resins, urea-formaldehyde resins, isocyanurate resins, acrylated urethane resins, vinyl
• Examples of grinding aid that can be incorporated into either a coated abrasive article, a nonwoven abrasive article or a bonded abrasive article include waxes, organic halide compounds, halide salts, and metals and their alloys
• the organic halide compounds will typically break down during abrading and release a halogen acid or a gaseous halide compound
• Examples of such materials include chlorinated waxes, such as tetrachloronaphthalene, pentachloronaphthalene, and polyvinyl chloride
• Examples of halide salts include sodium chloride, potassium cryolite, sodium cryolite, ammonium cryolite, potassium tetrafluoroborate, sodium tetrafluoroborate, silicon fluorides, potassium chloride, and magnesium chloride.
• the particle size of these precisely shaped filler particles and/or precisely shaped grinding particles should be controlled so that the bonding medium can be appropriately processed when the abrasive article is manufactured.
• the particle size of the precisely shaped filler particles and/or precisely shaped grinding aid particles should be less than about 100 micrometers, preferably less than about 50 micrometers such that tlie resulting make and/or size .coat can be properly coated.
• the bonded abrasive may utilize an organic bonding medium, a vitrified bonding medium or a metal bonding medium.
• the organic bonding mediums are described above, along with the additives that can be incorporated into the organic bonding maxim
• Other organic bonding mediums include rubber bonds and shellac bonds.
• the bonded abrasive may contain a rubber based bonding medium.
• One common bonding medium is a novolac phenolic bonding medium that is crosslinked with hexamethylenetetramine. Examples of commercially available phenolic bonding mediums include Varcum 8121 (liquid resole) and Varcum 7909 (powdered novolac) from Varcum Chemical Company, Niagara Falls, NY.
• the bonded abrasive may be made in such a manner that the abrasive grain of the invention is only present in the outer portion or rim of the wheel
• the depressed center wheels usually grind on the flat face In the center of the wheels is a mounting means to connect this wheel to a tool
• the mounting means may be a center hole forming an arbor hole
• these depressed center wheels contain a flat center or a depressed center
• the depressed center wheels may be molded to the shape of a shallow dish or saucer with curved or straight flaring sides
• the back side (i e , the side opposite of the abrasive coating) of the depressed center wheels may contain a reinforcing fabric, a reinforcing paper backing or some other support means such as a metal or plastic plate
• the bonded abrasive can be used dry or wet During wet grinding, the bonded abrasive
• the abrasive articles of this invention may further contain conventional abrasive agglomerates or individual abrasive grits or both Conventional abrasive agglomerates are further described in U S Patent Nos 4,31 1 ,489, 4,652,275; and 4,799,939
• Individual abrasive grits can also be selected to have a precise shape
• Examples of individual abrasive grits include fused aluminum oxide, ceramic aluminum oxide, heat treated aluminum oxide, silicon carbide, alumina zirconia, diamond, ceria, cubic boron nitride, garnet, and combinations thereof At least 10%), preferably at least 50%>, and most preferably at least 70%>, of the abrasive material should be the precisely shaped abrasive particles of this invention
• the individual abrasive grits can be disposed over the precisely shaped abrasive particles
• the individual abrasive grits can be
• One preferred supersize coat is a crosslinked epoxy resin, optionally a thermoplastic polymer and grinding aid particles such as cryolite, chiolite or tetrafluoroborate particles.
• This type of supersize coat is further described in European Patent Application No. 486,308 and U.S. Patent No. 5,441 ,549.
• the coated abrasive may optionally contain a supersize coating which prevents the coated abrasive from "loading"
• the various materials forming either the make coat, size coat and/or supersize coat will depend in part upon the final coated abrasive product requirements and the intended abrading application for the coated abrasive.
• the precisely shaped particles of the invention may also be incorporated into a lapping coated abrasive article
• This lapping coated abrasive article comprises a backing having a front and back surface and an abrasive coating bonded to the front surface of the backing
• the abrasive coating comprises a plurality of precisely shaped abrasive particles distributed throughout a make coat
• a bonded abrasive article comprises a plurality of abrasive grits bonded together by a bonding medium (e.g., cured resinous adhesive) to form a shaped mass At least a portion of the outer surface of the bonded abrasive is designed to contact a workpiece This outer surface that contacts the workpiece comprises the bonding medium and an abrasive layer
• the abrasive layer will comprise the precisely shaped particles of the invention and optionally other particles.
• the surface area percentage of the precisely shaped grinding aid particles in the abrasive layer may range from about 5 to 90, preferably 20 to 40 Additionally the method of making the abrasive article may result in the individual abrasive grits either over, under and/or between the precisely shaped grinding aid particles.
• the precisely shaped grinding aid particles have the potential to be very advantageous in abrasive articles.
• the bonding medium may not be compatible with a grinding aid
• resole phenolic resins are used as a precursor for the bonding medium and this resole phenolic resin is cured or crosslinked with basic pH.
• acidic grinding aids may be desired such as potassium tetrafluoroborate.
• the potassium tetrafluoroborate may interfere with the polymerization of certain resole phenolic resins. This level of interference will depend in part upon the chemistry of the particular resole phenolic resin.
• a precisely shaped grinding aid particle will have the grinding aid essentially encapsulated within the binder.
• the abrasive layer may comprise precisely shaped abrasive particles and diluent particles
• diluent particles can be selected from the group consisting of: 1 ) an inorganic particle (non abrasive inorganic particle), 2) an organic particle, 3) a composite diluent particle containing a mixture of inorganic particles and a binder and 4) a composite diluent particle containing a mixture of organic particles and a binder
• the particle size of these diluent particles can range from about 0 01 to 1500 micrometers, typically between 1 to 1000 micrometers
• the diluent particles may have the same particle size and particle size distribution as the precisely shaped abrasive particles Alternatively, the diluent particles may have a different particle size and particle size distribution as the precisely shaped abrasive particles
• the weight ratio of the precisely shaped abrasive particles to the diluent particle can range anywhere from about 1 to 99 parts precisely shaped a
• the selection and amount of the coating will depend upon the desired properties of the particle. For instance, some coatings will result in a retro-reflective particle. Alternatively, some coatings will improve adhesion of the particle to other materials or a substrate. It is also within the scope of this invention to use the precisely shaped particles as a loose abrasive slurry
• abrasive slurries typically comprise a mixture of precisely shaped particles and a liquid medium.
• the precisely shaped particles may further comprise abrasive grit(s), grinding aid(s), filler(s) or lubricant(s).
• the precisely shaped particle may comprise binder, abrasive grit and a grinding aid or lubricant
• abrasive grits, grinding aids and fillers are described above in detail
• lubricants include waxes, metal salts of fatty acids, sulfur based compounds, graphite, molybdenum disulfide, talc, boron nitride, silicones, silicone oils, polyglycols, phosphate esters, silicate esters, neopentyl polyol esters and polyphenyl ethers, fluorochemicals, mineral oils, combinations thereof and the like
• the liquid medium is generally water (including deionized watei , tap water or distilled water) and sometimes organic solvent Sometimes, the liquid is a mixture of water and other additives such as lubricants, rust inhibitors, coupling agents, anti-foams, anti-bacterial compounds, de-greasing compounds, oils, grinding aids,
• the present invention can be used to refine a wide range of workpiece surfaces
• workpiece surfaces include metal (including mild steel, carbon steel, stainless steel, gray cast iron, titanium, aluminum and the like), metal alloys (copper, brass and the like), exotic metal alloys, ceramics, glass, wood (including pine, oak, maple, elm, walnut, hickory, mahogany, cherry and the like), wood like materials (including particle boaid, plywood, veneers and the like), composites, painted surface, plastics (including thermoplastics and reinforced thermoplastics), stones (including jewelry, marble, granite, and semi precious stones), magnetic media, and the like
• Additional examples of glass workpieces include glass television screens, eye glass lenses, glass ophthalmic surfaces, windows (including home windows, office windows, car windows, air windows, train windows, bus windows and the like), glass display shelves, mirrors and the like.
• precisely shaped particles may consist essentially of only binder
• the precisely shaped particles may further comprise abrasive grits, fillers, grinding aids, lubricants or combinations thereof.
• ASF amorphous silica particles having an average surface area of 50 m 2 /g commercially available from DeGussa Corp. (Richfield Part, NJ), under the trade designation "OX-50"
• the precisely shaped particles were prepared on the apparatus similar to that illustrated in FIG 8, except that an ultrasonic horn was installed on the back side of the carrier web.
• a production tool was provided, in a continuous web form, that comprised a series of cavities with specified dimensions. These cavities were arranged in a predetermined order or array such that the production tool was essentially the inverse of the desired shape and dimensions of the precisely shaped particles.
• the production tool was made from a polypropylene thermoplastic material that had been previously embossed by extruding the polypropylene material over a master tool
• the nickel master tool also contained a series of cavities with specified dimensions and shape.
• the size coat was brushed over the abrasive grits/precisely shaped particles layer.
• the size coat was also a conventional cryolite filled resole phenolic resin (32% resin, 68% ⁇ cryolite).
• the resulting construction was heated for about 90 minutes at 93°C and then 12 hours at 100°C to fully cure the resole phenolic resin.
• the wet make coat weight was approximately four grams/disc and the wet size coat weight was approximately nine to ten grams/disc.
• the fibre discs were flexed prior to testing and humidified for 7 days at 45% relative humidity.
• the grinding aid precisely shaped particles were incorporated into a coated abrasive disc having a backing made of vulcanized fibre. These fibre discs were individually made and had a diameter of 17.8 cm with a center hole having a diameter of 2.2 cm.
• the make coat was a conventional calcium carbonate filled resole phenolic resin (48%> resin, 52% CaCO ). The precisely shaped particles were first drop coated into the make coat precursor. Next, CAO 1 abrasive grits were electrostatically coated over the grinding aid particles and into the make coat. The resulting construction was heated for about 90 minutes at about 88°C to partially cure the resole phenolic resin.
• the size coat was brushed over the abrasive grits/precisely shaped particles layer.
• the size coat was also a conventional cryolite filled resole phenolic resin (32% resin, 68%> cryolite).
• the resulting construction was heated for about 90 minutes at 93°C and then 12 hours at 100°C to fully cure the resole phenolic resin.
• a conventional potassium tetrafluoroborate filled epoxy resin supersize was coated over the size coat and subsequently cured.
• the coating weights for the make coat, size coat and supersize coat were conventional coating weights for the particular grade of CAO1.
• the coated abrasive disc was first mounted on a beveled aluminum back-up pad and then used to grind the face of a 1 25 cm by 18 cm 1018 mild steel workpiece.
• the disc was driven at 5,500 rpm at no load while the portion of the disc overlaying the beveled edge of the back-up pad contacted the workpiece at a load of about 5 9 kg
• the coated abrasive disc contacted the workpiece at angle between 6 to 7 degrees
• Each disc was used to grind a separate workpiece for one minute intervals for a total grinding time of 10 minutes
• the amount of metal removed (i.e total cut) during the entire test was measured There were two coated abrasive discs tested per example
• the abrasive article was converted into a 203 cm by 6 3 cm endless belt and was installed on a Thompson grinding machine
• the effective cutting area of the abrasive belt was 203 cm by 2 54 cm
• the workpiece was 304 stainless steel, 2 54 cm width by 17 78 cm length by 10.2 cm height and was mounted on a reciprocating table
• Abrading was conducted along the 2 54 by 17 78 cm face
• the abrading process used was conventional surface grinding wherein the workpiece was reciprocated beneath the rotating abrasive belt with incremental downfeed between each pass
• the abrading conditions were approximately 254 micrometers downfeed, 7.6 meters/minute table speed, and a belt speed of about 1710 surface meters/second
• the workpiece was cooled with a water spray (with 1%> rust inhibitor) The test endpoint was when the abrasive belt was no longer effectively cutting
• the coated abrasive articles for Examples 1 through 6 were made according to General Procedure 1 for Making the Coated Abrasive Article.
• the coated abrasive article for Comparative Example A was made according to General Procedure 1 for Making the Coated Abrasive Article except that the article did not contain precisely shaped grinding aid particles
• Example Particle (grams/square inch) (grams/square inch) (grams/square inch)
• the precisely shaped grinding aid particles for Examples 32 and 37 were made in the same manner as Example 31 , except that the run speed was 100 feet per minute (30 5 meters/minute)

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Manufacturing & Machinery (AREA)
• Polishing Bodies And Polishing Tools (AREA)

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• 1996
  • 1996-09-11 BR BR9612737A patent/BR9612737A/pt not_active IP Right Cessation
  • 1996-09-11 CA CA002264872A patent/CA2264872A1/en not_active Abandoned
  • 1996-09-11 EP EP99125307A patent/EP1038637B1/de not_active Expired - Lifetime
  • 1996-09-11 EP EP96932205A patent/EP0925151B1/de not_active Expired - Lifetime
  • 1996-09-11 WO PCT/US1996/014570 patent/WO1998010896A1/en active IP Right Grant
  • 1996-09-11 DE DE69629054T patent/DE69629054T2/de not_active Expired - Lifetime
  • 1996-09-11 JP JP10513587A patent/JP2001500068A/ja not_active Ceased
  • 1996-09-11 DE DE69637418T patent/DE69637418T2/de not_active Expired - Lifetime
  • 1996-09-11 AU AU71083/96A patent/AU7108396A/en not_active Abandoned
• 1997
  • 1997-08-20 ZA ZA977477A patent/ZA977477B/xx unknown

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