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Publication numberUS3802130 A
Publication typeGrant
Publication dateApr 9, 1974
Filing dateMay 1, 1972
Priority dateMay 12, 1971
Also published asCA965957A1, DE2222947A1
Publication numberUS 3802130 A, US 3802130A, US-A-3802130, US3802130 A, US3802130A
InventorsLindenbeck Dirk-Alfred
Original AssigneeEdenvale Eng Works
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
And like grinding wheels
US 3802130 A
Abstract
A peripheral grinding wheel wherein the peripheral grinding portion contains diamond or cubic boron nitride abrasive particles and is characterised in that it consists of two co-axial sections, the one section being a coarse section and containing coarse particles of between 60/80 mesh and 100/120 mesh and the other being a fine section containing fine particles of between 170/200 and 300/350 mesh, or in that it consists of a fine section sandwiched between two coarse sections, in each case the concentration of abrasive particle in the fine section preferably being greater than the concentration of abrasive particle in the coarse section.
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Description  (OCR text may contain errors)

United States Patent 1191 Lindenbeck 451 Apr. 9, 1974 [54] DIAMOND AND LIKE GRINDING WHEELS 2,594,137 4/1952 Doermann 51/207 [75] Inventor: DirbAlmd Lindenbeck, Randburg, 1,616,53l 2/1927 Klllg 51/207 South Africa 7 Primary Examiner-Donald G. Kelly [73] Assignee: Edenvale Engineering Works Attorney, Agent, or Firm-v-Young & Thompson (Proprietary) Limited, zllliil'llnesblll'g, Transvaal, South ABSTRACT A peripheral grinding wheel wherein the peripheral [21] Appl 248972 grinding portion contains diamond or cubic boron nitride abrasive particles and is characterised in that it [30] Foreign Application Priority Data consists of two co-axial sections, the one section being May 12, 1971 South Africa 71/3105 a coarse Section and Containing Coarse Pattie!es f tween 60/80 mesh and 100/120 mesh and the other [52] US. Cl. 51/207 being/a fine Section Containing fine Particles of 51 Int. Cl 1124a 5/14 tween 170/200 n 300/550 in that it 531 Field f Search; 51 207 204 20 1x20 4 sists of a fine section sandwiched between two coarse 5 2 9 R sections, in each case the concentration of abrasive 1 I particle in the fine section preferably being greater 5 References Cited than the concentration of abrasive particle in the UNITED STATES PATENTS 3,067,55l 12/1962 Maginnis Si/207 X 7 Claims, 2 Drawing Figures DIAMOND AND LIKE GRINDING WHEELS Thisinvention relates to peripheral grinding wheels incorporating as abrasive particles diamond or cubic boron nitride. V f f f Peripheralgrinding wheels include a hub portion having a central bore therein adapting the hub portion to be mounted on a shaft or spindle. The hub portion is itself formed from some suitable support material commonly used in the art such as steel, bakelite or a light metal. Carried on the periphery of the hubportion in a position to make effective contact with a workpiece, is the effective grinding portion. This portion commonly has a thickness of the, order of either onefourth inch or one-eighth inch (approximately 6 mm and 3 mm respectively). This peripheral portion has abrasive particles such as diamond embedded in a cured synthetic resin or metal matrix.

Peripheral grinding wheels which incorporate abrasive particles such as aluminum oxide or silicon carbide can be suitably dressed both'forgood grinding efficiency, i.e. high stock removal, and for relatively low grinding efficiency, i.e. good surface finishing or polishing. When good grinding efficiency is first required then good polishing for a given workpiece, it is possible to dress the same wheel to achieve both effects. However, dressing a peripheral grindingwheel incorporating diamond or cubic boron nitride is not easily achieved and hence different wheels have in the past generally been required to achieve both high stock remove] and good surfacefinish.

It is an object of the present invention to provide a peripheral grinding wheelincorporating diamond or cubicboron nitride abrasive particles which minimises the abovementioned shortcomings of similar wheels of 5 the prior art. 1

According to the invention, there isprovided a peripheral grinding wheel having an'effective grinding portion containing diamond or cubic boron nitride abrasive particles, characterised in that the effective grinding portion, comprises two co-axial sections, the one section having coarse particles and providing, in use, a high stock removal (hereinafter referred to as the coarse section) and the other section having fine particles and providing, in use, a good surface finish (hereinafter referred to as the fine section");

In one form of the invention, the effective grinding portion consists of two such co-axial sections.

In another form of the invention, the effective grinding portion consists of a central fine section sandwiched between two outer coarse sections.

The coarse section is preferably wider than the fine I section the width in any given case being influenced by the amount of crossfeed during grinding. The widths of the sections will preferably be 20 percent or more greater than the amount of crossfeed.

It has been found that particularly good results are achieved if the concentration of abrasive particle in the fine section or sections is greater than, preferably three times greater than, the concentration of abrasive particle in the coarse section or sections. As is known, concentration is determined by taking the weight of abrasive particle per unit volume of the finished grinding element. The grinding element in'this ease-is the effective grinding portion. The concentration is expressed relative to a standard of where the weight of abra- The preferred concentrations of abrasive particle in the fine section will vary with matrix being used. In the case of a cured synthetic resin matrix, the preferred concentration of abrasive particle in the fine section or sections is 100 to 150. In the case of a metal matrix, the preferred concentration of the abrasive particle in the fi'ne'section or sections is 100 to 300.

The preferred concentration of abrasive particle in the coarse sectionor sections is 50 to 100, irrespective of the matrix material.

The fine abrasive particles preferably have a size between 170/2 00 mesh and 300/350 mesh andthe size of the coarse particles is preferably between 60/80 mesh and 100/120 mesh.

To ensure good retention of the abrasive particles in the matrix of the wheel it is preferred that the particles are metal coated.

Two embodiments of the invention are described with reference to the accompanying diagrammatic drawing which show, in end view, the effective grinding portions of two peripheral grinding wheels according to the invention.

Referring now to FIG. 1, there is shown the effective grinding portion 10 of a peripheral grinding wheel which consists of two co-axial sections 12 and 14. Section 12 is the fine section and contains fine diamond grit of size 170/200 mesh while the section 14 is the coarse section and contains coarse diamond grit of size 60/70 meshrThe grit concentration of the fine section is (i.e. 108 carats per cubic inch).while the grit concentration of the coarse sectionis 50. The matrix material for both sections is cured synthetic resin and the-diamond grit is metal coated grit known as DX DA MC. e

In the wheel 20 of, FIG. 2, there are three sections, 22, 24 and26. The sections 22 and 26 are the coarse sections with grit size and concentration as for the section 14. The section 24 is the fine section, with grit size and concentration as for the section 12. The-matrix material is again synthetic resin and the grit is DX DA MC.

In use, thewheels are used for grinding workpieces such as metal workpieces. Considering first the wheel according to FIG. 2, 'a grinding process can be carried out with cross-feeds from opposite directions. As the grinding progresses, so the sharp edges 28 (shown in' dotted lines) of the effective grinding portion will be worn away and become rounded, as indicated in solid lines in the drawing. The outer sections 22, 26 will remove-most of the material being ground whereas the central section 24 will polish the surface left by the outer sections.

Because of the curved profile of the wheel 20, a waviness may be left on the workpiece surface. In order to reduce this waviness, the grinding wheel 10 of FIG. I may be used for grinding with the crossfeed being applied in only one direction i.e. the crossfeed of the workpiece in the direction of the arrow 16. The profile of this wheel, in use, will have less curvature than that shown in FIG. 2, the curvature being indicated by solid lines in FIG. 1. This will have the effect of considerably reducing the waviness. Furthermore, such a grinding process is more efficient as a greater amount of the diamonds are used during grinding. Therefore, lower wheel costs and better surface finish are obtained when an abrasive wheel, as shown in FIG. 1 is used with crossfeed in only one direction.

The illustrated embodiments have been described using metal coated diamond grit, but cubic boron nitride abrasive particles may also be used.

I claim:

1. A peripheral grinding wheel having an effective grinding portion containing abrasive particles selected from diamond and cubic boron nitride abrasive particles, characterised in that the effective grinding portion comprises two co-axial sections, the one section containing coarse particles, from 60/80 mesh to 100/120 mesh in size, and the other section containing fine particles, from 170/200 mesh to 300/350 mesh in size, and the concentration of abrasive particle in the section containing the fine particles being greater than the concentration of abrasive particle in the section containing the coarse particles.

2. A wheel according to claim 1 wherein the effective grinding portion consists of two and only two sections.

3. A wheel according to claim 1- wherein the efi'ective grinding portion consists of a central section containing fine particles sandwiched between two outer sections containing coarse particles.

4. A wheel according to claim 1 wherein the ratio of the concentration of abrasive particle in the section containing the fine particles to the concentration of abrasive particle in the section containing the coarse particles is 3:1.

5. A wheel according to claim 1 wherein the matrix of the effective grinding portion is a cured synthetic resin and the concentration of the abrasive particle in the section containing the fine particles is to and the concentration of the abrasive particle in the section containing the coarse particles is 50 to 100.

6. A wheel according to claim 1 wherein the matrix of the effective grinding portion is a matrix metal and the concentration of abrasive particle in the section containing the fine particles is 100 to 300 and the concentration of abrasive particle in the section containing the coarse particles is 50 to 100.

7. A wheel according to claim 1 wherein the abrasiv particles are metal coated.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US1616531 *Aug 8, 1922Feb 8, 1927Norton CoCutting-off abrasive wheel
US2594137 *Sep 12, 1949Apr 22, 1952Titan Abrasives CompanyGrinding wheel
US3067551 *Sep 22, 1958Dec 11, 1962Bethlehem Steel CorpGrinding method
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3936982 *Nov 21, 1974Feb 10, 1976Margaret SissonSharpening stone for dehorners
US3982358 *Apr 23, 1975Sep 28, 1976Heijiro FukudaLaminated resinoid wheels, method for continuously producing same and apparatus for use in the method
US5228241 *Sep 17, 1991Jul 20, 1993Toyoda Koki Kabushiki KaishaMethod and machine for grinding
US5329735 *Jun 8, 1992Jul 19, 1994Charlton Thomas JSystem for forming and polishing grooves in glass panels
US5853319 *Sep 12, 1996Dec 29, 1998Ernst Winter & Sohn Diamantwerkzeuge Gmbh & Co.Grinding tool
US5888129 *May 15, 1997Mar 30, 1999Neff; Charles E.Grinding wheel
US5951381 *Nov 25, 1996Sep 14, 1999Briot InternationalGrinding wheel for ophthalmic glasses and corresponding grinding machine
US5996571 *Feb 1, 1996Dec 7, 1999Diamond Products Joint VentureDiamond core drill bit
US6159286 *Nov 4, 1998Dec 12, 2000Sung; Chien-MinProcess for controlling diamond nucleation during diamond synthesis
US6286498Sep 20, 1999Sep 11, 2001Chien-Min SungMetal bond diamond tools that contain uniform or patterned distribution of diamond grits and method of manufacture thereof
US6402607 *Dec 18, 2000Jun 11, 2002The Gleason WorksFine-machining tool for machining gear workpieces
US6638152 *Sep 3, 1999Oct 28, 2003Ehwa Diamond, Ind., Co., Ltd.Diamond blade having segment type cutting tip for use in cutting, grinding or drilling apparatus
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US6827641 *Mar 3, 2003Dec 7, 2004Noritake Co., Ltd.Grinding wheel having synthetic resin layers covering axially opposite end faces of body of the wheel
US6875098 *Jan 5, 2001Apr 5, 2005Mitsubishi Materials CorporationElectroplated grinding wheel and its production equipment and method
US7089925Aug 18, 2004Aug 15, 2006Kinik CompanyReciprocating wire saw for cutting hard materials
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US7201645Sep 29, 2004Apr 10, 2007Chien-Min SungContoured CMP pad dresser and associated methods
US7527050 *May 18, 2006May 5, 2009Saint-Gobain Abrasives Technology CompanyMethod for fabricating multi-layer, hub-less blade
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Classifications
U.S. Classification451/544
International ClassificationB24D5/00, B24D5/14
Cooperative ClassificationB24D5/14
European ClassificationB24D5/14