US2290631A

US2290631A - Abrasive tool and method of making same

Info

Publication number: US2290631A
Application number: US398429A
Authority: US
Inventors: Buchmann Louis
Original assignee: ALNCIN Inc
Current assignee: ALNCIN Inc
Priority date: 1941-06-17
Filing date: 1941-06-17
Publication date: 1942-07-21
Anticipated expiration: 1959-07-21

Description

BUCHMANN 2,290,631

ABRASIVE-TOOL AND METHOD OF MAKING SAME I Filed June 17, 1941.

' INVENTOR 100/5 zQ/CHMA/V/V Patented July 2 1, 1942 2,290,631 anaasrvn 'roor. AND METHOD or MAKING SAME Louis Buchmann, Bu flalo. N. Y., assignor to AlnCin, Inc., Buffalo, N. Y.

Application June 17, 1941, Serial No. 398,429

18 Claims.

This invention relates to abrasive tools-and to methods of making the same. More specifically, the invention relates to an improved method for making solid metallic tool bodies containing abrasive grains distributed therethrough and fixed therein in an improved manner.

The invention contemplates a novel and improved method for fabricating the metallic body portion or abrasive grain bonding medium thereof, and an improved method of mounting the abrasive grains therewithin.

One object of the present invention is to provide an improved method for mounting abrasive granules within a solid metal tool body, whereby the abrasive granules are locked within the tool body in an improved manner and whereby crushing of the abrasive granules during the mounting process is avoided.

Another object of the present invention is to provide an improved abrasive tool comprising individual abrasive grains and a bonding medium for uniting the whole into anintegral structure of improved strength; the abrasive grains being distributed throughout the structure in an improved manner and in accord with a predetermined plan of arrangement.

Another object of the present invention is to provide an improved abrasive wheel of increased structural strength.

Another object of the present invention is to provide an improved method of introducing the abrasive granules into the bonding medium during manufacture of an abrasive tool.

Another object of the invention is to provide an improved abrasive tool in which the abrasive ingredients thereof are distributed throughout the body of the tool in accord with any desired plan of varying concentration, and in which the abrasive granules are locked within the body of the tool in an improved manner and are unchanged from the grain size in which the abrasive granules were originally furnished.

Another object of the invention is to provide an abrasive tool wherein the abrasive granular ingredients thereof are distributed throughout the body of the tool in such manner as to expedite and make more economical the redressing of the cutting face of the tool subsequent to intermittent use thereof in an improved manner.

. Other objects and advantages of the invention will appear from the specification herein.

In the drawing:

Fig. 1 is a side elevation of a typical abrasive wheel of the invention;

Fig. 2 is a typical section through the wheel of Fi Fig. 3 is a diagrammatic sectional view through a moldand press apparatus illustrating a step of the fabrication method of the invention; a Fig. 4 is a fragmentary section, on an enlarged scale, through a matrix forming element having mounted thereon abrasive granules preliminary to final fabrication of a tool of the invention;

Fig. 5 is a side elevation of another form of abrasive carrying wheel of the invention;

Fig. 6 is atypical sectional view through the wheel of Fig. 5; and

Fig. 7 is a plan view, on an enlarged scale, of a fragment of a fabricating element of the wheel of Figs. 5 and 6, showing the mounting of -abrasive granules thereon in accord with the method of the invention.

In practicing the invention, the abrasive grits to be employed are united with a novel form of bonding medium which is made up by assembling in laminated manner sheets of the bonding material. For example, as illustrated in Figs. 1-4, a wheel [0 of the invention is shown as comprising a series of discs I l which are formed of sheet metal disposed in side-by-side relation and pressed and fused together to form a unitary.

mass in the desired form of the abrasive wheel. The discs H may be either of smooth surface form or they may be in the form of deformed sheets; knurled or scratched or acid-etched or otherwise treated to provide abrasive retaining pockets therein. The metal sheets H are preferably formed of a metallic substance which is initially relatively soft and "mushy at temperatures below the fusion point thereof, and readily weldable and adapted to receive subsequent heat treatments for tempering to desired degrees of hardness and toughness, for purposes as will be explained hereinafter.

the discs are then arranged in superposed relation and subjected to a fusing temperature and then to pressure as provided for by opposed die devices l5 and I6 (illustrated diagrammatically in Fig. 3). For example, in order to provide the abrasive ingredients of the wheel in concentrated form in the regions of the most active working portions of the wheel, the individual discs going into the make-up of the most active working portions of the wheel will preferably be coated with increased concentrations of abrasive as compared to the discs: going into the make-up of the relatively inactive portions of the wheel. Thus, in connection with the manufacture of a V-shaped groove cutting wheel as illustrated in Fig. 2, the center discs II will be initially coated with greater quantities of abrasive kernels than are the discs at the opposite side portions thereof. The ridge-like peripheral form of the wheel may be obtained either by providing the discs I I of appropriately different diameters whereby the building up of the laminated structure will automatically provide the approximate form desired and avoid waste of expensive abrasive grains, or by using discs of equal diameters ond subsequently dressing the wheel to desired form following the fusion process. Preferably, a temporary binder to hold the abrasive grains in position to time to cut away surface portions of the tool for reexposure of abrasively active portions thereof. Also, it is most desirable that the matrix be not too ductile such as would otherwise permit the abrasive granules to be rolled out of their sockets within the matrix; nor must the matrix be too brittle whereby it would be subject to undue disintegration under service conditions and the abrasive granules would tend to dislodge therefrom priorto full utilization of the abrasion capacities thereof.

I have found that for the purpose of the invention the disc elements II may be desirably formed of various grades of carbon steel, or of a copper base alloy containing froma small amount up to 16% aluminum, with or without appreciable addition of other metals such as iron, nickel, and perhaps tin and zinc. For example, a specific alloy which I have found to be extremely suitable for the purpose is a commercially available alloy containing approximately 89% copper; 10% aluminum; and 1% iron. Such plete volatilization ,under temperatures associ- I ated with the fusion of the metal sheets and is thus completely eliminated so that ultimately no other substance remains between the .abrasive granules and the fused metal.

It is contemplated that various kinds of abrasive granules may be employed in connection with the method of the invention and that the sizing of the abrasive granules will be regulated as desired and in accordance with the character of the work to be done by the finished tool. It

is also contemplated that in connection with the initial deposition of the abrasive granules upon the body elements I I any other suitable means for accomplishing the desired distribution may be employed, and that in lieu of lauryl alcohol any other suitable oily or greasy paste or liquid temporary adhesive substance may be employed, or that the abrasive grains may simply be dusted upon the strip elements without the use of any carrier substance.

In order to provide the matrix portions of the.

tools of the invention of preferred form, the invention contemplates usage of a special form of metallic substance which is adapted to be heattreated in a special manner subsequent to fabrication of the tools whereby the. matrix portions thereof are given improved characteristics for the purpose intended. For example, I have found that the disc elements II of Figs. 1-4 may, for certain tool purposes, be formed of an initially soft and temperable steel, or of a suitable member of the so-called copper base alloy group which is adapted to be heat-treated to provide in the finished product enhanced properties of metal fuses at from between 1700 F. to 1900 F.,

depending upon the proportion of the iron content, and thus is well suited to the method of 'the invention in connection with the fabrication of abrasive tools employing diamond dust or the like because of non-production of deleterious effects upon the abrasive ingredients at such temperatures. I have found that subsequent to the heating and pressing fabrication method of the invention as-described hereinabove, when employed in connection with the metallic alloy substances specified, the fabricated tools may be then heat-treated by heating and quenching in water at from 1500 F. to 1600i F'., followed by tempering at. between .100 F. and 1200 F. Such treatment imparts to the matrix substance of the finished tool optimum strength and ductility characteristics which provide a "self dressing" tool adapted to perform most efficiently from the standpoint of utilization of the abrasion capacities of the abrasive granules disposed within the matrix. Similar suitable heat treating processes may be applied to the welded tool of the invention when fabricated of steel matrix forming elements as explained hereinabove, for providing the finished product of the desired gritretaining characteristics. Preferably, the

which are interspersed the abrasive particles in accord with the predetermined plan of their relative arrangement therein.

A particular feature of the invention resides in that the metallic laminae for fabrication of the tool are selected so as to be initially relatively soft and adapted to readily soften at temperatures just below the temperature of welding so that the abrasive grains may be originally furnished of uniform desired size and will then become mounted within the body structure of the tool without having been crushed or structurally weakened during the tool assembly process. Such crushing of the abrasive granules between the adjacent metal surfaces will be avoided because of the softness of the metal and the low degree of pressure needed to be applied to bring the metallic laminae into intimate welding position, Thus, the abrasive granules become permanently embedded within the solid coalized pure metallic mass of the tool body, and each abrasive granule is intimately enclosed at all sides only by pure metal. Hence, each abrasive granule remains intact as originally supplied, and of full dimensions and in structurally unweakened form whereby the grip of the metallic matrix upon the abrasive granule is of maximum strength and durability.

Thus, the invention clearly distinguishes from and provides marked improvements and advantages over prior methods for mounting abrasive granules within metallic holders. For example,

in order to avoid the well known disadvantages and structural weaknesses of sintered tool bodies, a previously customary method for mounting abrasive granules involves minute cutting into the outer surfaces of a metallic body and inlaying abrasive granules intothe cuts so produced, as by pounding or otherwise driving the abrasive therein. Obviously, such methods result in tremendous reduction of abrasive grain size and pulverizing thereof so that the granules become so fractured that the enclosing metal portions cannot cling solidly to the abrasive; whereas the tool of the present invention entirely avoids such destruction of the abrasive granules and encases each grain with a solid pure metal grip of maximum tenacity.

As illustrated in Figs. 5 and 6, another form of wheel IQ of the invention is shown as comprising a metallic core around about the periphery of which has been wound a metallic strip 22 to provide a plurality 'of layers, the number of which depends upon the desired depth of the working portion of the wheel. The

abrasive granules 24 for the wheel are positioned upon the metallic strip 22 prior to the wrapping of the strip about the core 28 by spreading a supply of the loose granules across the strip 22, and it will be understood that Fig. 4 also-illustrates the mounting of the abrasive granules 24 anon the base metal elements 22 of the inven- Upon completion of the process of winding the strip about the core ill, the 'wheel I9 is placed in a-furnace and/or otherwise subjected to an elevated temperature .at. about the degree of initial fusion of the metal of the strip 22 for a length, of time suillcient to provide thorough welding of adjacent portions of the grit-carrystrip without allowing the bulk, of the metal I thereof to become so fluid as to allow the impounded abrasive particles to move relative to the mass. Usually, an application of. pressure wheel will be richer in abrasive grit as compared to the side portions thereof. Consequently, the abrasive grit is employed inaccurately controllable manner; and wasteful employment of abrasive kernels in the relatively inactive portions of the wheel is avoided thus eiiecting substantial economies whenever the abrasive kernels are of the expensive type" such as diamond dust or the like. Also, it will be seen that because. of the fact that the relatively in-,

tion may he obtained in ways other than hereinabove described in connection with preparation of the strip 22. For example, a strip of uniform character may be employed and the abrasive grits may he applied thereto in any suitable manner so as to give the desired form of grain distribution. For example, the coating of abrasive carrying substance l8 which is applied to the strip preparatory to winding thereof about the core may be applied of increased thickness along the center line of the strip; or, the strip may be painted by multiple operations involving the application of a. mixture along the center line of the strip that contains a higher percentage of abrasive to the carrier employed as compared to the percentage 01' abrasive to the carrier employed in connection with the painting of the of the strip.

In any case it will be seen that the object is to locate the abrasive kernels in accord with a predetermined desired manner of, distribution throughout the wheel body by temporarily imnent elements entering into the assembly of the abrasive wheel and subsequently fusing the upon the structure during the heating process will also be beneficial and of assistance in pro- 'viding a thorough welding.

Whenever the stock to be operated upon by the wheel is not initially shaped complementary to the shape of the wheel cutting face, that section of the wheel that is called upon to do the maincreased number of grits per unit of area in the central portion of the strip as'compared to theside edge portions thereof. Hence, when the strip 22 is wound about the core 20 and fused.

into place thereon, the central section of the 76 made by fusingxranular metallic mixtures.

elements thereottogether into a unitary mass of high structural strength without substantially disturbing the distribution and relative concentration of the abrasive kernels throughout difl'erent portions of the wheel mass;

Thus, the method oi! the invention provides a rugged welded structure wherein the matrix portion thereof is of pure coalized metal form. This provides a tool of greater structural strengthas compared to the so-called "sintered" wheels of the prior art, for example, which are In the case of such sintered types of tools the finished products are of crystalline-like structural form and resemble in appearance crusty masses of granules adhering to one another by reason only of intermittent andspace'd points of welded contact, and the masses are usually interspersed with multitudes of minor voids.

Thus, the abrasive grains are at best only partially surrounded by and attached to the'bonding material. Consequently. the finished products foif'such prior methods are usually nonuniform as to structural strength and often contain weak zones which are apt to cause un- Provide a tool that is made up of a plurality of side edge portions united solid metallic bodies extending throughout the tool structure; and therefore, even though the fusion process of the method of the present invention may not in some instances be carried out to perfection between all of the adjacent'surrace portions thereof, the tool will neverthelesshe reinforced throughout by the unaltered integral solid metallic bodies. Thus, in no case will the tool of the invention be subject to disruption under stress in the manner of sintered wheels, or the like. In the case of production of tools of the present invention in the form of abrasive wheels as illustrated in the drawing, it will be seen that the laminated strip structures Ht-22, upon being welded together provide tools that are positively reinforced circumi'erentially against centrifugal and/or other forces tending to disrupt them during use.

The avoidance of conditions of fluidity in the metal of the structure during the fusion process precludes the possibility or redistribution of the abrasive grains in the mass and/or undesirable segregation thereof as would otherwise occur under conditions of mass metal fluidity; and the planned unequal distribution of abrasive particles throughout the wheel mass is accordingly obtained in the finished product. It is of course contemplated that the strip elements l ll22 may be bent or dished or otherwise deformed in any desired manner before being relatively assembled so as to provide any desired form of interlocking laminated structure.

It will be understood that the invention is applicable with equal facility to the manufacture of a large variety of abrasive tool shapes such as are suitable for use in connection with a multiplicity of industries, and that although only a limited number of the forms of the invention have been shown and described in detail herein, various changes may be made therein without departing from the spirit of the invention or the scope of the appended claims,

I claim:

l. The method of fabricating an abrasive tool including the steps of arranging abrasive granules between metallic sheet material while holding said abrasive granules in position therebetween in accord with a plan' of irregular distribution to provide a fabrication assembly, heating said metallic material to soften the latter so that said abrasive granules may press into said metallic material without becoming subjected to granule-crushing pressures, pressing said assembly together while heated to metallic softened condition and heat-fusing and pressing the assembled metallic material and abrasive granules together to form a coalized body of metal with abrasive granules of unchanged form dispersed therethrough and intimately locked therein in accord with said plan of abrasive ranule distribution.

2. The method of fabricating an abrasive tool including the steps of applying lauryl alcohol to surface portions of metallic sheet materialand arranging abrasive granules upon said lauryl a1- cohol treated portions of said metallic sheet material for holding said abrasive granules in posia coalized body of metal with abrasive granules of unchanged form dispersed therethrough and intimately locked therein in accord with said plan of abrasive granule distribution.

3. The method of manufacturing an abrasive tool including the steps of applying an adhesive substance to surface portions 01 metallic material, mounting abrasive granules upon said applied adhesive substance in accord with a definite plan of abrasive granule distribution, arranging said metallic material to provide a laminated structure, heating said metallic material to soften the latter so that said abrasive granules may press thereinto without becoming subjected to granule-crushing pressures, pressing said laminated structure together while heated to metallic material softened condition, and sintering said structure into a unitary metallic body with said abrasive granules locked by sintered metal therein in accord with said definite plan of abrasive granule distribution, said adhesive substance being of such character as to be eliminated upon sintering of said structure.

a. The method of manufacturing an abrasive tool including the steps of providing in association with surface portions of metallic discs means for temporarily pocketing in fixed relation thereon abrasive granules in accord with a definite plan of abrasive granule unequal distribution whereby the concentration of said granules varies with respect to different of said discs, arranging said discs into the form of a single 1aminated structure with said abrasive granules temporarily supported by said pocketing means therewithin, heating said metallic material to soften the latter so that said abrasive granules may press thereinto without becoming subjected to granule-crushing pressures, pressing said laminated structure together While heated to metallic material softened condition, and fusing the metallic portions of said laminated structure together so asto provide a unitary body with said abrasive granules locked by said fused metallic portions therewithin in accord with said definite plan of abrasive granule distribution, said granule temporary pocketing means being of such character as to be eliminated upon fusin of said structure.

5. The method of manufacturing an abrasive wheel tool comprising the steps of applying adhesive substance to a surface portion of a metallic strip element, pocketing abrasive granules in fixed relation upon said adhesive substance, said abrasive granules being distributed in accord with a-definite plan of abrasive granule unequal distribution whereby the concentration of said granules is reater on one sectiona1 zone of said strip element than on another sectional zone thereof, coiling said strip element to provide a wheel structure, heating said metallic material to soften the latter so that said abrasive granules may press thereinto without becoming subjected to granule-crushing pressures, pressing said laminated structure together while heated to metallic material softened condition, and fusing said wheel structure into a unitary metallic body with said abrasive granules locked by fused metaltherein in accord with said definite plan of abrasive granule distribution, said adhesiv substance being of such character as to be volatilized and dissipated upon fusing of said structure.

6.: The method of manufacturing an abrasive tool comprising the providing in association with surface portions of metallic discs means for temporarily pocketing in fixed relation thereon abrasive granules in accord with adefinite plan of abrasivegranule unequal distribution whereby the concentration of said granules varies with respect to different of said discs, arranging said discs into the form of a single laminated structure with said abrasive granules temporarily supported by said means therewithin, heating said metallic material to soften th latter so that said abrasive granules may press thereinto without becoming subjected to granule-crushing pressures, pressing said laminated structure together while heated to metallic material softened condition, and fusing the metallic portions of said laminated structure together so as to provide a unitary body with said abrasive granules locked by said fused metallic portions therewithin in accord with said definite plan of abrasive granule distribution, said granule temporary pocketing means being of such character as to be volatilized and dissipated upon fusing of said structure.

7. The method of manufacturing an abrasive tool comprising the steps of arranging in association with a surface portion of a copper-aluminum alloy metallic strip element means for temporarily pocketing in fixed relation upon said strip element abrasive granules in accord with a definite plan of abrasive granule unequal distribution whereby the concentration of said granules is greater in one sectional zone of said strip element than in another sectional zone thereof, said granule temporary pocketing means being of such character as to be eliminated under elevated temperature conditions, arranging said abrasive mounting strip to provide a laminated structure, and fusing said structure into a unitary metallic body with said abrasive granules locked by fused metal therein in accord with said definite plan of abrasive granule distribution, and subsequently tempering the metallic structure of the tool by heating and quenching processes.

8. The method of manufacturing an abrasive tool comprising the steps of providing in association with surface portions of copper-aluminum alloy metallic laminae means for temporarily pocketing in fixedrelation thereon abrasive granules in accord with a definite plan of abrasive granule unequal distribution whereby the concentration'of said granules varies with respect to different of said laminae, said granule temporary pocketing means being of such characte" as to be eliminated upon fusing of said metallic laminae, arranging said laminae into the form of a single laminated structure with said abrasive granules temporarily supported by said means therewithin, and fusing the metallic portions of said laminated structure together so as to provide a. unitary body with said'abrasive granules locked by said fused metallic portions therewithin in accord with said definite plan of abrasive granule distribution, and subsequently tempering the metallic portion of said tool by heating and quenching processes.

9. An abrasive tool comprising copper-aluminum ailoy laminae having abrasive granules pocketed thereon in accord with a definite plan of unequal distribution, said laminae being fused to provide a coalized body, said body having been heat treated for temperingof the metallic alloy content thereof.

10. The method of manufacturing an abrasive tool comprising the steps of arranging in association with a surface portion of a steel metallic strip element means for temporarily pocketing in fixed relation upon said strip element abrasive granule unequal distribution whereby the concentration of said granules is greater in one seetional zone of said strip element than in another sectional zone thereof, said granule temporary pocketing means being of such character as to be eliminated under elevated temperature conditions, arranging said abrasive mounting strip to provide a laminated structure, and fusing said structure into a unitary metallic body with said abrasive granules locked by fused metal therein in accord with said definite plan. of abrasive granule distribution, and subsequently tempering the metallic structure of the tool by heating and quenching processes.

11. The method of manufacturing an abrasive tool comprising the steps of providing in association with surface portions of steel laminae means for temporarily pocketing in fixed relation thereon abrasive granules in accord with a definite plan of abrasive granule unequal distribution whereby the concentration of said granules varies with respect to different of said laminae, said granule temporary pocketing means being of such character as to be eliminated upon fusing of said metallic laminae, arranging said laminae into the form of a single laminated structure with said abrasive granules temporarily supported by said means therewithin, and fusing the metallic portions of said laminated structure together so as to provide a unitary body with said abrasive granules locked by said fusedmetallic portions therewithin in accord with. said definite plant of abrasive granule distribution, and subsequently tempering the metallic portion of said tool by heating and quenching processes.

12. The method of manufacturing an abrasive tool comprising the steps of arranging in association with a surface portion of a heat temper- -able strip element means for temporarily pocketstrip to provide a laminated structure, and fusing said structure into a unitary metallic body with said abrasive granules locked by fused metaltherein in accord with said definite plan of abrasive granule distribution, and subsequently tempering the metallic structure of the tool by heating and quenching processes.

13L The method of manufacturmgan abrasive tool comprising the steps of providing in association with surface portions of temperable laminae means for temporarily pocketing in fixed relation thereon abrasive granules in' accord with a definite plan of abrasive granule unequal distribution whereby the concentration of said granules varies with respect to different of said laminae,

' said granule temporary pocketing means being of such character as to be eliminated upon fusing of said metallic laminae, arranging said laminae into the form of a single laminated structure with said abrasive granules temporarily supported by said means therewithin, and fusing the metallic portions of said laminated structure together so as to provide a unitary body with said abrasive granules locked by said fused metallic portions therewithin in accord with said definite granules in accord with a definite plan of abrasive 56 plan of abrasive granule distribution, and subsequently tempering the metallic portion of said tool by heating and quenching processes.

14. An abrasive tool comprising steel laminae having abrasive granules pocketed thereon in accord with a definite plan of unequal distribution, said laminae being fused to provide a coalized body, said body having been heat treated for tempering of the metallic content thereof.

15. An abrasive tool comprising temper-able metallic laminae having abrasive granules pocketed thereon in accord with a definite plan of unequal distribution, said laminae beingiused to provide a coalized body, said body having been heat treated for tempering of the metallic content thereof.

16. The method of manufacturing an abrasive tool comprising acid etching surface portions of metallic laminae to provide pocket means, temporarily pocketing in fixed relation thereon abrasive granules in accordrwith a definite plan of abrasive granule distribution whereby the concentration of said granules varies with respect to diflerent of said laminae, arranging said laminae into the form of a single laminated structure with said abrasive granules temporarily supported by said pocketing means therewithin, and sintering the metallic portions of said laminated structure together so as to provide a unitary body with said abrasive granules locked by said sintered metallic portions therewithin in accord with said deflnite plan of abrasive granule distribution.

17. The method of manufacturing an abrasive tool comprising applying to surface portions of metallic laminae lauryl alcohol, temporarily pocketing in fixed relation thereon abrasive granules in accord with a definite plan of abrasive granule distribution whereby the concentration of said granules varies with respect to different of said laminae, arranging said laminae into l metallic laminae a volatile substance, temporarily pocketing in fixed relation thereon abrasive granules in accord with a definite plan of abrasive granule distribution whereby the concentration of said granules varies with respect to. difierent of said laminae, arranging said laminae into the form of a single laminated structure with said abrasive granules temporarily supported by said volatile substance therewithin, and sintering the metallic portions of said laminated structure together so as to provide a unitary body with said abrasive'granules locked by said sintered metallic portions therewithin in accord with said deflnite plan of abrasive granule distribution.

LOUIS BUCHNLANN.