US2418529A - Embrittled silver solder bonded abrasive - Google Patents

Embrittled silver solder bonded abrasive Download PDF

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US2418529A
US2418529A US56655544A US2418529A US 2418529 A US2418529 A US 2418529A US 56655544 A US56655544 A US 56655544A US 2418529 A US2418529 A US 2418529A
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wheel
abrasive
particles
mica
grinding
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Stern Albert
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Stern Albert
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    • BPERFORMING OPERATIONS; TRANSPORTING
    • B24GRINDING; POLISHING
    • B24DTOOLS FOR GRINDING, BUFFING, OR SHARPENING
    • B24D3/00Physical features of abrasive bodies, or sheets, e.g. abrasive surfaces of special nature; Abrasive bodies or sheets characterised by their constituents
    • B24D3/34Physical 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
    • B24D3/342Physical 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
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B24GRINDING; POLISHING
    • B24DTOOLS FOR GRINDING, BUFFING, OR SHARPENING
    • B24D18/00Manufacture of grinding tools or other grinding devices, e.g. wheels, not otherwise provided for

Description

April 8, 1947. l A STERN 2,418,529

EMBRITTLED SILVER SOLDER BONDED ABRASIVE Filed Dec. 4, 1944 Patented Apr. 8, 1947 ERIBRITTLED SILVER SOLDER BONDED ABRASIVE Albert Stern, Chicago, Ill.

Application December 4, 1944, Serial No. 566,555

`i Claims.

AMy invention relates to a grinding wheel and more particularly to one utilizing diamond for its cutting action.

In grinding wheels the cutting action of the abrasive particles is at peak eiciency only when each particle may present unencumbered cutting edges to the material being worked upon. One of the principal drawbacks in the use of abrasive Wheels is termed glazing, caused by par.. ticles of material removed from the work embedding themselves in the spaces intermediate the cutting particles and thus interfering with the free action of the cutting edges. When glazing occurs it will rapidly build up to a stage where the wheel must be redressed to expose a fresh surface of abrasive to the Work. Not only is this wasteful because of the discarded abrasive removed by the dressing operation but the work must be discontinued until dressing has been accomplished. Thus, useful production time is sacriiced. FurthermoreLin thecase of diamond wheels `dressing is a slow and difficult operation.

Many attempts have been made to overcome glazing and eliminate redressing but without success, as the material thus far used to bond the wheel is generally of the same degree of plasticity and hardness as the particles of metal removed from'the Work and the bonding agent and the particles therefore conglomerate into a homogeneous mass Where the original intention was that the particles of metal should embed themselves in the bonding agent and leave uninterrupted abrasive cutting particles projecting from the surface of the wheel.

I have found that anon-glazing Wheel may be constructed in which the matrix comprises the principal abrasive ingredient, for example, diamond, together with another abrasive ingredient, for example, silicon carbide, and a bonding and filling agent including ilakelets of mica and silver solder. While the theory of operation of my wheel is not thus far fully understood, one theory of operation seems to be that the mica and silver solder together form a sufficiently dense and tenacious bonding agent while being subject to easy attrition as the wheel wears in use. This may be due in part to the aky nature of mica which imparts a lubricating quality permitting superimposed akelets to slide one upon the other and be severed from the mass. Thus, as grinding proceeds, the particles 'of metal removed by the wheel will dislodge the nakelets and the silver solder dispersed between the abrasive parseries of cuttingfedges of the abrasive proper to be presented to the work.

Accordingly, the principal object of my invention is to provide a non-glazing grinding wheel in which the abrasive particles including one or more cutting materials are embedded in a matrix including comminuted mica and silver solder.

An additional object of my invention is t0 provide a non-glazing grinding Wheel in which the matrix is of such character as to provide cleavage planes in the bonding agent.

Still another object is to provide a non-glazing grinding wheel including material subject to easy cleavage combined with material serving as a bonding agent for the abrasive particles.

Other objects are to provide a grinding wheel which will enable dry grinding to be done without glazing and to decrease the time of a grinding operation.

A further object of the invention is to provide a grinding wheel which is cooler in o ration.

Another object is to enable the production of wheels of various grades by variation in the proportion of mica content.

An additional object is to provide a wheel including mica as part of the matrix whereby the latter is less brittle and hence not easily subject to breakage in use.

Other objects will appear as the description proceeds.

In the drawings:

Fig. 1 is substantially a diagrammatic view of an apparatus in which the grinding wheel of the invention may be fabricated;

Fig. 2 is a diametrical cross section of a grinding wheel of the cup type embodying a grinding portion in accordance with my invention;

Fig. 3 is a magnified 'view through a portion of the work and a portion of the wheel, the cross section being taken to show the relative movement between the abrasive surface and the work; and

Fig. 4 is a fragmental portion of Fig 3 on an even greater enlarged scale intended to show the theory of operation of my new wheel.

Referring rst to Fig. 1, there is a hollow cylindrical molding chamber 9 in the aperture I0 of which is deposited a series of wheel blanks II cylindrical in form and including a plurality of concentric keying grooves I2 adjacent the outer periphery of one fiat face I3 thereof. .Adjacent the face I3 of each blank II is a molding element I4 having a peripheral recess I5 .of cross section to correspond with the contour of the ticles and continuously allow a freshly exposed grinding surface to be produced, i. e., rectangular, 'semi-circular, etc. Each of the blanks and' units Il is pierced with a substantially central aperture IB, all in alignment.

In loading the chamber 8 there is first placed on the bottom a mass of a suitable fusible or t thermoplastic bonding agent 20, e. g., silver solder, then a molding element I4 with its recess I5 uppermost. In the recess is substantially uniformly distributed material comprising a mixed predetern ined quantity 2| of principal abrasive particles. e. g., diamond of a mesh suitable for the work to be performed by the wheel and of substantially uniform mesh, comminuted abrasive material of a hardness less than diamond, for example, silicon carbide, available commercially in one form under the trade name Carborundum, and preferably of iiner mesh than the principal particles, andA comminuted mica which, due to the nature of the material, will be yielded as minuteflakelets. A sufficient quantity 0f this mixture is distributed loosely into and piled slightly over the recess I5, the quantity being'measured in advance and determined upon empirically. After the mixture 2| is thus deposited a wheel blank is set into place as shown. Then another complete unit comprising an element I4, a mass of the mixture 2|, 'and a wheel blank is set in position, and so on, there being as many sets as is permitted by the capacity of the molding machine.

The entire molding unit is encased in a shield 22 extending upwardly into a hood 23 having a vent opening 24. Through apertures in the sides of the enclosure 22 extend a plurality of heating jets 25, only two being shown for clarity. Illuminating gas or any other suitable combustible fluid may be admitted to the jets 25 and ignited so that the flames play upon the outer-,surface of the chamber 9. The contents of the chamber, including the bonding agent 20 will be raised in temperature and when the agent reaches flowing temperature a piston 26 at the lower end of a screw 21 and fitting the aperture i0 is brought down upon the contents of the chamber, the pressure being sufiicient to displace the melted mass of agent 20upwardly through the central openings I6 -and then radially outwardly in the spaces 28 :intermediate each blank and element I4 and into the interstices of the mixture 2|.

The pressure is applied gradually and the agent v sustained in melted condition until the gaps 28 are entirely closed. When this occurs the mass of abrasive material, bonding agent and mica has been pressed into a homogeneous solid mass of the desired dimensions. Part of this mass enters the grooves |2 which serve to lock'the annular abrasive portion proper of the wheel rmly to the wheel blank Il. Piston 26 is retracted, the chamber 9 allowed to cool, and the several complete wheel units may then be withdrawn.

The wheel units may be used in disc-like form as shown in Fig. 1 or may be turned on a lathe to any other desired shape, for example, cupped,

`as shown in Fig. 2.

ticles 3|, e. g., diamond, sometimes commercially y 4' in comminuted form and ofa mesh finer than the bort, and 331/3% of mica akelets of a mesh finer than the bort. The silver solder or otherv bonding agent whichk bonds the entire matrix is not to be considered a part of the proportions of the mix but only as a bonding agent. It will be understood that the size of the recess I5 and `0|! the gap 28 may be so designed with respect to the amount of abrasive and the mica that only suilicient bonding agent to effect a thorough bond will be permitted to flow for formation of .a niatrix of the desired proportions.

In operation the particles of diamond will perform the major part of the grinding operation and these will be assisted by the particles of silicon carbide. However, it is intended that the latter named particles shall have a glaze-preventing action. 'I'hat is, as attrition of the wheel occurs the particles of silicon carbide will be permitted to move within the mass to permit breaking down of the bonding agent and to assist in the movement of the mica flakelets. Otherwise stated, the action is intended to be similar to that occurring in a ball mill.

The mica iiakelets, at least according to my theory of operation, tend to separate the bonding agent into disconnected strata. Hence, as attrition occurs those particles of silver solder near the surface slide freely on the mica flakelets and on each other and are carried away, either by the air stream in dry grinding or the lubricant in wet grinding, thereby leaving a constantly exposed cutting surf ace of diamond.

In Fig. 4, the reference numeral 35 indicates a high spot of the work which the grinding operation is intended to remove and it is shown midway between two diamond particles 3| and 3Ia. It is intended that a particular diamond particle 3 la shall be the next t0 perform the cutting operation and it will be noted that the highv not limited to a diamond wheel but is capable of being embodied in any type of wheel, for example, one including silicon carbide alone as the abrasive agent. The gist of the invention resides in the inclusion of the mica fiakelets with thematrlx, and by mica I refer to any of those minerals commonly sold under the name mica,

there being several ,technically'diiferent types found in nature. However, they are all charac terized by forming flakelets when comminuted, the natural planes of cleavage of -mica yielding thin planiform particles or wafers having distinctive lubricating qualities when in such form.

One important advantage in the use of mica for the purpose outlined is its extreme resistance to disintegration under heat. Thus, although the wheel may reach a high temperature in operation, the mica fiakelets will not break down into a form not possessing the desired characteristics outlined hereinabove. Notwithstanding the fact that the wheel may reach relatively high .temperatures in operation during dry grinding, itis substantially cooler when wet grinding is being done. By reason of the fact that the mica is friable, pores are created in the matrix as grind-- ing proceeds. These pores impart a spongy characteristic to the wheel enabling it to absorb substantial quantities of water and to cool the wheel.

Since the mica is a material relatively softer than the other ingredients of the wheel, it is possible, by varying the proportion of mica, to construct wheels of varying degrees of hardness. Such gradation in the so-called hardness" of the wheel renders the same exactly suited to the type of work being done. Metal bonded diamond wheels now known to the art are incapable of being so controlled in hardness.

Inasmuch as the wheel of my invention is, generally speaking, softer than other diamond wheels, it is not as subject to breakage, the matrix being more brous in nature as contrasted with the brittle construction of wheels presently known.

Trial has shown that the Yimproved wheel of my invention is capable of increasing production as much as 30% over similar wheels not incorporating my improved matrix and that this increase is-due to the non-glazing characteristic thus achieved.

Although I have shown by way'of illustration the invention embodied in a grinding wheel, it will be comprehended that the abrasive composition is capable of use in other forms, for example, awhetstone.

Further modifications will be apparent to those skilled in the art and it is desired, therefore, that the invention be limited only by the scope of the appended claims. Y

Having thus described my invention, what I claim and desire to secure by Letters Patent is:

1. A substantially non-glazing abrasive body comprising a bonding matrix of silver solder having embedded therein substantial quantities of s ing embedded therein substantial quantities each of diamond particles of substantially uniform size and silicon carbide and mica particles that are both smaller in size than said diamond particles.

10 3. A substantially non-glazing abrasive body comprising a silver solder bonding matrix having embedded therein substantial quantities each of abrasive particles of substantially uniform size and mica particles that are smaller in size than 15 said abrasive particles.

4. A substantially non-glazing abrasive body comprising a bonding matrix oi' silver solder having embedded therein about equal parts each of silicon carbide particles of substantially uniform 2o size and mica particles that are smaller in size than said silicon carbide particles.

ALBERT STERN.

25 REFERENCES CITED 1 UNITED sTA'rEs PATENTS 30 Number Name l Date 1,907,088 Novotny May 2, 1933 2,197,655 Boyer f l Apr. 16, 1940 2,223,063 Fitz-Randolph Nov. 26, 1940 2,306,423

Bemtorl! et al. Dec. 29, 190

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Cited By (22)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2630659A (en) * 1948-05-13 1953-03-10 Saint Gobain Method of surfacing solid bodies
US2697043A (en) * 1950-10-24 1954-12-14 Fmc Corp Wear resisting material
US2705194A (en) * 1950-08-01 1955-03-29 Clair John Quincy St Diamond tools and method of making the same
US4239502A (en) * 1978-11-17 1980-12-16 General Electric Company Diamond and cubic boron nitride grinding wheels with improved silver alloy bonds
EP0179404A2 (en) * 1984-10-22 1986-04-30 Toyoda Van Moppes Limited Grinding tool
US20090105059A1 (en) * 2002-11-06 2009-04-23 Khaled El Dorry Controlled centrifuge systems
US20090120846A1 (en) * 2005-11-16 2009-05-14 George Alexander Burnett Shale shakers with cartridge screen assemblies
US20090145836A1 (en) * 2007-12-11 2009-06-11 Paul William Dufilho Vibratory separator screens & seals
US20090178978A1 (en) * 2008-01-14 2009-07-16 Randy Charles Beebe Drilling fluid treatment systems
US20090227477A1 (en) * 2006-10-04 2009-09-10 National Oilwell Varco Reclamation of Components of Wellbore Cuttings Material
US20090242466A1 (en) * 2002-10-17 2009-10-01 George Alexander Burnett Automatic Vibratory Separator
US20100038143A1 (en) * 2008-08-14 2010-02-18 George Alexander Burnett Drill cuttings treatment systems
US20100089652A1 (en) * 2008-10-10 2010-04-15 National Oilwell Varco Shale Shakers with Selective Series/Parallel Flow Path Conversion
US20100089802A1 (en) * 2008-10-10 2010-04-15 George Alexander Burnett Systems & methods for the recovery of lost circulation & similar material
US7980392B2 (en) 2007-08-31 2011-07-19 Varco I/P Shale shaker screens with aligned wires
US8201693B2 (en) 2006-05-26 2012-06-19 National Oilwell Varco, L.P. Apparatus and method for separating solids from a solids laden liquid
US8231010B2 (en) 2006-12-12 2012-07-31 Varco I/P, Inc. Screen assemblies and vibratory separators
US8312995B2 (en) 2002-11-06 2012-11-20 National Oilwell Varco, L.P. Magnetic vibratory screen clamping
US8622220B2 (en) 2007-08-31 2014-01-07 Varco I/P Vibratory separators and screens
US9073104B2 (en) 2008-08-14 2015-07-07 National Oilwell Varco, L.P. Drill cuttings treatment systems
US9079222B2 (en) 2008-10-10 2015-07-14 National Oilwell Varco, L.P. Shale shaker
US9643111B2 (en) 2013-03-08 2017-05-09 National Oilwell Varco, L.P. Vector maximizing screen

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1907088A (en) * 1930-09-06 1933-05-02 John Stogdell Stokes Abrasive body and method of making the same
US2197655A (en) * 1936-07-28 1940-04-16 Carborundum Co Article made from powdered mixes and its manufacture
US2223063A (en) * 1937-10-07 1940-11-26 Carborundum Co Abrasive article
US2306423A (en) * 1939-10-04 1942-12-29 Bernstorff Hans Grinding and cutting body

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1907088A (en) * 1930-09-06 1933-05-02 John Stogdell Stokes Abrasive body and method of making the same
US2197655A (en) * 1936-07-28 1940-04-16 Carborundum Co Article made from powdered mixes and its manufacture
US2223063A (en) * 1937-10-07 1940-11-26 Carborundum Co Abrasive article
US2306423A (en) * 1939-10-04 1942-12-29 Bernstorff Hans Grinding and cutting body

Cited By (34)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2630659A (en) * 1948-05-13 1953-03-10 Saint Gobain Method of surfacing solid bodies
US2705194A (en) * 1950-08-01 1955-03-29 Clair John Quincy St Diamond tools and method of making the same
US2697043A (en) * 1950-10-24 1954-12-14 Fmc Corp Wear resisting material
US4239502A (en) * 1978-11-17 1980-12-16 General Electric Company Diamond and cubic boron nitride grinding wheels with improved silver alloy bonds
EP0179404A2 (en) * 1984-10-22 1986-04-30 Toyoda Van Moppes Limited Grinding tool
EP0179404A3 (en) * 1984-10-22 1987-04-29 Toyoda Van Moppes Ltd Grinding tool
US8746459B2 (en) 2002-10-17 2014-06-10 National Oilwell Varco, L.P. Automatic vibratory separator
US20090242466A1 (en) * 2002-10-17 2009-10-01 George Alexander Burnett Automatic Vibratory Separator
US8172740B2 (en) 2002-11-06 2012-05-08 National Oilwell Varco L.P. Controlled centrifuge systems
US8695805B2 (en) 2002-11-06 2014-04-15 National Oilwell Varco, L.P. Magnetic vibratory screen clamping
US8561805B2 (en) 2002-11-06 2013-10-22 National Oilwell Varco, L.P. Automatic vibratory separator
US20090105059A1 (en) * 2002-11-06 2009-04-23 Khaled El Dorry Controlled centrifuge systems
US8312995B2 (en) 2002-11-06 2012-11-20 National Oilwell Varco, L.P. Magnetic vibratory screen clamping
US20090120846A1 (en) * 2005-11-16 2009-05-14 George Alexander Burnett Shale shakers with cartridge screen assemblies
US8118172B2 (en) 2005-11-16 2012-02-21 National Oilwell Varco L.P. Shale shakers with cartridge screen assemblies
US8201693B2 (en) 2006-05-26 2012-06-19 National Oilwell Varco, L.P. Apparatus and method for separating solids from a solids laden liquid
US20090227477A1 (en) * 2006-10-04 2009-09-10 National Oilwell Varco Reclamation of Components of Wellbore Cuttings Material
US8533974B2 (en) 2006-10-04 2013-09-17 Varco I/P, Inc. Reclamation of components of wellbore cuttings material
US8316557B2 (en) * 2006-10-04 2012-11-27 Varco I/P, Inc. Reclamation of components of wellbore cuttings material
US8231010B2 (en) 2006-12-12 2012-07-31 Varco I/P, Inc. Screen assemblies and vibratory separators
US8622220B2 (en) 2007-08-31 2014-01-07 Varco I/P Vibratory separators and screens
US7980392B2 (en) 2007-08-31 2011-07-19 Varco I/P Shale shaker screens with aligned wires
US20090145836A1 (en) * 2007-12-11 2009-06-11 Paul William Dufilho Vibratory separator screens & seals
US20090178978A1 (en) * 2008-01-14 2009-07-16 Randy Charles Beebe Drilling fluid treatment systems
US8133164B2 (en) 2008-01-14 2012-03-13 National Oilwell Varco L.P. Transportable systems for treating drilling fluid
US20100038143A1 (en) * 2008-08-14 2010-02-18 George Alexander Burnett Drill cuttings treatment systems
US9073104B2 (en) 2008-08-14 2015-07-07 National Oilwell Varco, L.P. Drill cuttings treatment systems
US8556083B2 (en) 2008-10-10 2013-10-15 National Oilwell Varco L.P. Shale shakers with selective series/parallel flow path conversion
US20100089802A1 (en) * 2008-10-10 2010-04-15 George Alexander Burnett Systems & methods for the recovery of lost circulation & similar material
US8113356B2 (en) 2008-10-10 2012-02-14 National Oilwell Varco L.P. Systems and methods for the recovery of lost circulation and similar material
US20100089652A1 (en) * 2008-10-10 2010-04-15 National Oilwell Varco Shale Shakers with Selective Series/Parallel Flow Path Conversion
US9079222B2 (en) 2008-10-10 2015-07-14 National Oilwell Varco, L.P. Shale shaker
US9677353B2 (en) 2008-10-10 2017-06-13 National Oilwell Varco, L.P. Shale shakers with selective series/parallel flow path conversion
US9643111B2 (en) 2013-03-08 2017-05-09 National Oilwell Varco, L.P. Vector maximizing screen

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