US1996598A

US1996598A - Abrading tool

Info

Publication number: US1996598A
Application number: US357536A
Authority: US
Inventors: George F Taylor
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1929-04-23
Filing date: 1929-04-23
Publication date: 1935-04-02
Anticipated expiration: 1952-04-02
Also published as: GB349732A

Description

April 2, 1935. G, F. TAYLOR ABRADING TOOL Filed April 25, 1929' 2 sheets shee 1 Inventor:

George? TaLJLOT;

His Attorney April 1 G. F. TAYLOR 99659 ABRADING TOOL Filed April 23, 1929 '2 Sheets-Sheet 2 F ig.6.

55 i F ;J

Inventor George F. Tag \or,

j A I His Attorngg It is one of the objects of the present invention to hard materials such as quartz, sapphire, hard and the mixed powders heated to the sintering molybdenum stems.

Patented Apr. 2, 1935 UNITED STATES v PATENT o-rr cs ABRADING TOOL George F. Taylor, Schenectady,

General Electric Company, New York Application Apiil23, 1 929, Seria l No. 357,536 20 Claims. (01. 15-1) N. Y., asslgnor tov a corporation of The present invention relates to abrading tools. tained between the diamond particles and binder material or matrix is that the matrix at its sintering temperature wets the diamonds and forms a strong adhesive bond with them.

The novel features which I believe to be characteristic of the invention are set forth with-particularity in the appended claims. The-invention itself however will. best be understood from. reference to the following specification when considered in connection with the accompanying 10 drawings in which Fig. 1 is a perspective view of a portion of a press and mold in which heat and pressure may be simultaneously applied to the I powdered materials employed in producing drills; Fig. 2 is a cross sectional view of the mold shownin Fig. 1; Fig. 3 is a perspective view of a drill constructed in accordance with the presentinvention; Fig. 4 is a cross sectional view of a mold in which a plurality of drill heads may be formed simultaneously; Fig. 5 is a perspective view of a' modified form of drill the head portion of which is formed by the process illustrated in Fig. 4; Fig. 6 is a. cross sectional view of an apparatus whereby a supporting plate may be provided with a defi nite amount of mixedpowdered materials; Fig. '7 is a perspective view partly broken away of the apparatus shown in Fig. 6, while Fig. 8 is a cross sectional view of a carbon mold whereby heat and pressure may be applied to the powdered materials and supporting plate disclosed in Figs. 6 and 7.

Referring moreparticularly to the drawings, I have indicated at l a carbon mold having upper and lower plungers 2 and 3 respectively. The lower plunger 3 is provided on its upper surface with a relatively large number of spaced longitudinally disposed holes 4 which have a diameter equal to. the diameter of the drill it is desired to construct.

A press designed as a whole by the reference numeral 5 cooperates with the mold l and includes a plunger 6 and a base member I. The press is provided with a pair of adjustably mounted terminals 8 and 9 which may be connected to a suitable source 'of electric current through conductors i0 and H. The opposing faces of the terminals are provided with carbon blocks l2 and I3 having right angled openings therein adapted to accommodate the rectangular shaped mold I.

In making drills suitable for cutting quartz, sapphire and the like, Imix about one volume of diamond powder with about 3 to 4 volumes of a powdered composition consisting of tungstencarbide and cobalt, the cobalt'forming about 3 provide an improved abrading tool which is particularly adapted for use in drilling or surfacing metals, and hard metal alloys.

In carrying my invention into effect, I provide a supporting member or shank with a cutting or abrading portion which consists of finely di- -vided diamond dust or powder uniformly distributed through a sintered binder material. .The

diamond powder, which may be of varying de--' grees of fineness according to the work to be performed, is thoroughly mixed with the powdered binder composition. The latter consists mainly of a hard metal carbide, such as tungsten-carbide, but contains an auxiliary cementing metal such as cobalt. A binder composition of this character is disclosed in the patents to Schrdter No. 1,549,615 and, in general, consists of a carbide of an element of the 6th group of Mendelejeffs periodic table and metal of the iron group, the metal of the iron group constituting from about 3 to about 25% of the total content'of the composition.

The diamond powder and binder composition are thoroughly mixed in desired proportions which may vary according to the work to be performed.

In making drills, the mixed powdered materials are placed in a series of spaced openings in a mold and compressed slightly. Molybdenum rods or stems are inserted in the openings in the mold temperature-of the binder composition, that is, about 1350 to 1380 C. while pressure equal to about 1000 pounds to the square inch is simultaneously applied to'the upper exposed ends of the In making a lapping tool, the powdered materials are evenly deposited on a molybdenum supporting-member or plate and heated to the sintering temperature of the binder material while pressure is simultaneously applied to the supporting plate and powdered materials. In this manner the supporting member is firmly welded to the cutting portion of the tool. The minute diamond particles or dust are uniformly distributed through and firmly held in position by the binder composition. The cutting surface of the tool is abrasive and remains so throughout its life due partly to the distribution of the diamond powder through the binder and partly to the firmness with which the diamond particles are held in position by the binder material. The explanation of the firm junction obto 25% of the powdered composition. The powdered mixture is poured into the holes 4 in the lower plunger 3 so as to fill them almost completely. Molybdenum rods M are then pressed into the holes to slightly compress the powdered mixture. The lower plunger 3 with the molybdenum rods protruding from the openings therein, is then placed in the mold I. The plunger 2 is inserted in the mold I on top of the molybdenum stems and the mold and plungers positioned in the press 5. Electrodes 8 and 9 are then adjusted by means of screws l and IE to clamp the mold I firmly in position between the carbon blocks 12 and I3 and underneath the plunger 6. Current is supplied to the mold and powdered materials through conductors l0 and H, while pressure is simultaneously applied through the plunger element 6. The powdered materials are heated to a temperature of about 1350 C. which is the sintering temperature of the binder material and the molybdenum stems are firmly pressed onto the powdered materials thereby forming a drill having a molybdenum shank and a sintered cutting tip.

Tools formed according to my process are not only suitable for drilling purposes but may be employed to smooth or face grinding wheels and the like. In the latter case it will be found desirable to employ a coarse diamond powder, for example a powder which will pass a 40 to 60 mesh, whereas for high speed drilling work, the diamond powder will have a fineness suflicient to pass a 100'mesh and for producing highly" polished surfaces the diamond powder will be even finer. I

The finished tool tip described above and made from a mixture consisting of about one volume of diamond powder with 3 to 4 volumes of binder material contains about 1 part by weight diamond powder to about to 13 parts by weight of binder material. While both the diamond powder and the binder material are abrasive in character, it is my opinion that the cutting action is due mainly to the diamond powder.

It is sometimes desirable to form a plurality of drill-heads at one time and to secure such drill heads to steel or other suitable shanks having diameters which may be smaller than the diameter of the drill head. This may be accomplished by providing a plunger N, Fig. 4, corresponding to plunger 3, Fig. 2, with a plurality of holes iii of relatively large diameter. A mixture IQ of binder element and diamond dust in sufilcient amount to form a drill head of desired dimensions is placed in each hole It and a thin layer 20 of tungsten powder spread over the mixture. Successive mixtures 2| and 22 may be placed in the holes l8 above the mixture l9. A thin layer 23 of graphite separates the successive mixtures and prevents them from sticking together.

Tungsten or molybdenum rods 24 may be inserted in the holes I8 and pressure applied to the upper ends thereof while the mixtures are simultaneously heated to the sintering temperature of the binder composition. The upper layer 23 of carbon prevents the tungsten or molybdenum rods 24 from sticking to the powdered mixtures 22. After 1: powdered mixtures have been pressed and sintered they may be removed from the plunger I1 and welded or brazed to steel or other suitable shanks 25.

On account of the large amount of diamond dust present in the powdered mixtures, it would ordinarily be dimcult to braze or weld the pressed drill heads to a shank. However, the thin layers of tungsten 20 provide means whereby the shank o1 a screw threaded member 3|.

portion of the tool may be readily brazed or welded to the drill heads.

Lapping tools suitable for use in grinding lenses or like materials where it is desirable that the grinding tool surface should not change appreciably in contour with continued use, may be produced by providing a suitable metal plate orsupporting member 26 (Fig. 6 with acoated surface consisting substantially oi the same powdered mixture which is employed in producing drills, i. e., about one part by weight diamond powder to about 10 to 13 parts by weight of binder material.

In constructing a lapping tool the mixed powdered materials may be sifted onto the plate 26 which may be made of tungsten or molybdenum or any material which will retain its shape at the sintering-temperature of the binder material, or the powdered materials may be mixed with a small amount of starch paste or water to produce a viscous paste having a consistency about the same as that of thick paint and applied in this manner to the plate or disc 26.

Disc 26 is loosely mounted on a plate 21 attached to the end of a plunger 28, the latter being movable in a metal casting 30 by means I The upper end of the casting 30 is provided with a recess 32 in which disc 26 may be raised or lowend. Any desired thickness of powdered materials may be produced on disc 26 by adjusting the member 3| and moving a rod 33 across the edges of the recessed portion 32 to thereby remove excess material. The plate 26 with the powdered mixture thereon is then placed in a suitable carbon mold 34 and between

plungers

35 and 36 and compressed. The mixture while it is being compressed is heated simultaneously to the sintering temperature of the binder material.

If desired, the binder material may be employed with refractory powdered materials other than diamond powder, for example boron carbide, carborundum, sapphire and the like. While good abrading tools may be made by employing the latter materials, such tools are somewhat inferior to those employing diamond powder as the cutting agent, and .are not adapted to cut extremely hard materials.

While I have illustrated my invention in connection with a solid cylindrical drill, it is clear that the drill may be made of hollow cylindrical form, as illustrated in my copending application Serial No. 357,537, filed April 23, 1929, and that various modifications may be made in the form of my improved cutting tool without departing from the scope of the present invention as set forth in the following claims.

What I claim as new and desire to secure by Letters Patent of the United States, is:

1. A tool having a cutting portion consisting of diamond particles and a cemented carbide binder, said diamond particles being distributed through said binder and forming a strong adhesive bond therewith.

2. A tool having a cutting portion consisting of diamond particles distributed throughout a. sintered binder composition, said binder composition consisting substantially of tungsten carbide and cobalt.

3. A tool having a cutting portion consisting of diamond particles and a binder composition therefor, said binder composition consisting substantially of a carbide of a metal of the 6th group of Mendelejefis periodic table and metal of the, iron group, said diamond particles being distribbinder composition,

' strong adhesive bond containng from about uted through said binder and held in position by a wetting action between said binder composition and said diamond particles.

4. A drilling tool comprising ametal shank and a cutting portion joined to one end of the shank, said cutting portion consisting of small diamond particles embedded in and distributed through a binder composition. said composition consistin substantially of cemented tungsten carbide, said diamond particles being held in position in said composition by a wettingaction oi the cemented carbide on said diamond particles.

5. A drilling tool comprising a metal shan a cutting portion Joined to one end or the shank. saidcutting portion consisting of small particles embedded in and distributed through a sintered binder composition and held therein by a strong adhesive bond, said composition consisting principally or tungsten carbide but containing an appreciable amount oi! cobalt.

'6. A tool having a cutting portion consisting oi diamond particles held in position in a sintered binder composition by a wetting action of said binder composition on said diamond particles, said binder composition consisting principally of tungsten carbide but containing an appreciable amount of cobalt, said diamond particles being distributed through said binder composition.

'7. A tool having a cutting portion consisting of about one part by weight of diamond particles and about 10 to 13 parts by weight of a sintered said diamond particles being, held in said binder composition by a wetting action of said binder composition on said diamond particles, said binder composition consisting mainly of tungsten carbide but containing more than 3% oi-cobalt.

8. A composition of matter consisting of about one part by weight of diamond particles and from about 10 to about 13 parts by weight of a cemented carbide binder, said binder forming a strong adhesive bond with said diamond particles and consisting of about 3% to about 25% cobalt with the remainder tungsten carbide.

9. A composition of matter consisting of about one part by weight diamond particles and from about to about 13 parts by weight of a cemented carbide binder, said binder forming a with said diamond particles and consisting of about 3% toabout 25% cobalt with the remainder tungsten carbide, said diamond particles being capable oi passing through a 40 to 100 mesh screen.

10. A composition of matter consisting 0! about one part by weight oi diamond particles and (ram about 10 to about 13 parts by weight of a sintered binder. said binder iorming a. strong adhesive bond with said diamond particles and 3% to about 25% cobalt with the remainder tungsten carbide. said diamond particles being capable of passing throughv a 40 to 60 mesh screen.

11. An article of manufacture consisting of diamond particles embedded in and distributed through a sintered binder of tungsten carbide and cobalt, said diamond particles being held in position by a wetting action or the binder on said diamond particles.

12. A hard, tough material suitable for tools and the like comprising tungsten carbide '78 to 86%, finely divided diamond dust I to 9%, and the remainder a metal of the cobalt group.

13. A material suitable for tools and the like containing an appreciable but minor quantity of diamond particles, the remainder consisting substantially of tungsten, carbon and cobalt.

14. A tool consisting of diamond particles uniiormly distributed through a sintered binder composition consisting of tungsten, carbon and metal oi. the iron group. I 15. The method of preparing hard tool stock which comprises sintering a mixture of pretermed tungsten carbide a metal of the iron group and small diamond particles to produce a composition in which the diamond particles are left in their original condition.

16. The method oi preparing a hard tool stock whch comprises sintering a mixture of powdered material and. small diamond particles to produce a composition in which the diamond particles are left in their original condition said powdered material consisting substantially of tungsten, carbon and cobalt.

17. The method of preparing a hard composition so as to incorporate diamond particles without disintegrating the which comprisesmixing finely divided diamond particles with a preformed tungsten carbide in which the metal is substantially completely satisfied with carbon, together with metal of the iron group and sintering the mixture under heat with coincident pressure.

1B. A material suitable for tools and the like containing an appreciable quantity of diamond particles, the remainder consisting substantially of tungsten carbide and cobalt, the cobalt comprising more than 3% of said remainder.

19. A tool having a cutting portion consisting of diamond particles and a cemented carbide binder therefor, said diamond particles being distributed through said binder and held in position by a wetting action or the binder on said diamond particles, said binder consisting principally of tungsten carbide but containing more than 3% of cobalt;

20. A tool having a cutting portion consisting oi diamond particles distributed throughout a cemented carbide binder material, said binder material comprising the major part by weight or said cutting portion, said diamond particles being held in position in said binder by a wetting action. said binder consisting substantially or tungsten carbide and cobalt, the cobalt content or said binder comprising morethan 3% by weight.

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