KR20000010841A - Grinding tool and production method thereof - Google Patents

Abstract

PURPOSE: A grinding tool used to the cutting, the punching, and the grinding of a constructing material is provided to have an excellent grinding efficiency, and not to generate the deterioration event. CONSTITUTION: The grinding tool contains:a construction(2) adhered in a circumference part, and located a diamond particle; a frame having an interspace in the outer surface of a column offered in a support unit(2) around the column of a support unit(6); the interspace held 30¯75% of the part; 100¯500 micron of the average of the interspace diameter, and 2mm of the maximum; the support unit(6) filled at least 70% of the interspace; the interspace formed by a metal or an alloy having over a using temperature of the tool and under 950°C.

Description

Abrasive tool and its manufacturing method

FIELD OF THE INVENTION The present invention relates, in particular, to abrasive tools used for cutting, drilling, grinding and the like of building materials, which tools are at least partially inserted into holes provided in the structure and which are made of a material which is made of a mold, cast, injection molded or pressed material. It consists of a structure in which diamond particles are placed and fixed to a surface or circumference. The invention relates in particular to a wear tool of the type described in International Patent Application No. PCT / BE95 / 00101.

In particular, the present invention relates to a preferred embodiment of an abrasive tool within the general construction of the above international patent application.

According to the invention, the structure consists of pores at least in the region near the circumference of the support, which occupy at least 30-75% of the body volume of this region and are open to the outside thereof, the average diameter of which is 100-500 microns, up to 2 mm, the support is introduced into at least 70% of these cavities and is made of a metal or alloy having a melting point above the tool's service temperature and below 950 ° C.

The support is preferably based on one of the alloys of these elements, such as an alloy comprising zinc, tin, aluminum, magnesium, copper or silicon.

The present invention relates to a method for producing the above abrasive tool.

This method allows the diamond particles to be positioned in three dimensions with a constant distance from each other according to the annular structure of the mold, wherein the support for the annular structure is provided with voids which are somewhat uniformly dispersed between the diamond particles in at least the structure region near the support. It is formed so as to occupy 30-75% of the body volume of the zone and is cast into the mold so that at least 70% of the cavity is introduced into the metal or alloy constituting the support with a melting point above the tool operating temperature and below 950 ° C in the liquid phase. The metal or alloy is then solidified to form a somewhat uniform connection between the annular structure in which the diamond particles are placed and the support.

Other features and details of the present invention will become apparent from the following detailed description of, but not limited to, specific embodiments of the abrasive tool and its manufacturing method with reference to the accompanying drawings.

1 is a cross-sectional view of the sintering mold in which an annular structure in which diamond particles are placed is formed;

2 is a perspective view of the annular structure showing the position of the diamond particles,

3 is a detailed enlarged view of a diamond located in an annular structure according to the first embodiment of the present invention,

4 is a detailed enlarged view showing a second embodiment of the diamond position of the annular structure according to FIG.

5 is a cross-sectional view of a casting mold comprising a structure in which diamond particles are located and an abrasive tool formed from a support fixed to the structure,

6 is a schematic cross-sectional view of a separated mold part,

7 is a schematic cross-sectional view of a mold part separated after matching,

8 is a schematic cross-sectional view of a mold part separated after finishing to form an abrasive tool,

9 is a cross-sectional view of an abrasive tool of FIG. 8 and another embodiment,

10 is a perspective view of a drill device showing an annular structure according to the present invention,

11 is a perspective view of a grinding wheel showing the annular structure according to the present invention.

Like reference numerals in the drawings denote like parts.

FIELD OF THE INVENTION The present invention relates to abrasive tools for cutting, drilling, grinding, and the like, wherein the tool comprises a structure in which the diamond particles are positioned three-dimensionally at regular intervals from each other and secured to a support forming a very tight connection.

The structure, hereinafter referred to as "diamond-loaded structure", comprises a cavity, at least partially in the vicinity of the support, that occupies at least 30-70% of the body volume of this region and at least partially opens to its outer surface. do. The average diameter of this cavity is 100-500 microns up to 2 mm. Supports for this purpose consist of metals or alloys that penetrate into at least 70% of these cavities, allowing a very strong connection between the structure and the support.

Moreover, this support must have a melting point higher than the abrasive tool operating temperature to prevent tool deterioration during use, and the melting point should be below 950 ° C for safe penetration of metals or alloys into the void without degrading the diamond particles of the diamond-embedded structure. .

As such, according to the invention, the support is based on one of the alloying of these elements, such as an alloy comprising zinc, tin, aluminum, magnesium, copper or silicon.

Excellent results have been obtained with abrasive tools having supports formed from an aluminum-silicon alloy comprising 5-9% preferably 7% silicon.

According to a particular embodiment of the invention, the structure is formed of particles composed of diamond particles which are three-dimensionally attached to each other by sintering and covered with a metal envelope.

Particles of this kind can be obtained by known techniques, as in U.S. Pat.

However, it should be noted that the present invention is not limited to the use of particles obtained by the above method.

The diamond-embedded structure is preferably composed of 1-15%, preferably 3%, by volume of diamond particles, to be maintained in the skeleton based on cobalt, iron, bronze or nickel.

This diamond embedded structure may, in some specific cases, be coated with other abrasive particles such as silicon carbide, silicon or aluminum oxide at a rate of 10 times less than the diamond particle volume.

For the manufacture of abrasive tools such as those mentioned, the first step is to place the diamond particles in three dimensions spaced apart from one another according to the annular structure in the mold, where the support is at least 30-75% of the body volume of this region in the region of the structure near the support. The voids are formed to be dispersed between the diamond particles so as to occupy. In the next step, the metal or alloy constituting the support can be cast into the mold in the liquid phase so that the metal or alloy can penetrate into at least 70% of the cavity. Finally, these metals or alloys solidify to form a connection between the annular structure and the support in contact with the cavity and at least partially cover the cavity.

Casting of metals or alloys refers to a permanent mold, ie, "fire resistant steel", as described in "American Metal Society Publishing, Metal Handbook, Volume 5, Forging and Casting, p265" (ASM Committee on Permanent Mold Casting Production). preferably in a refractory sleel).

The invention will now be described by way of examples in connection with the manufacture of stone cutting discs.

As shown in FIG. 1, the annular structure 2 in which the diamond particles 3 are located is first formed in the first mold 1.

This diamond-embedded structure 2 is located in the second mold 4, as shown in FIG. 5, and the material 5 forming the support 6 is injected into the mold in the liquid phase.

Particularly in order to form the annular structure 2, the particles 7 are introduced into the annular cavity 9 of the first mold 1, as illustrated in detail in FIG. 4, so that a metal envelope 8 is provided. It is formed from diamond particles 3 covered with snow. The annular cavity 9 in which the particles are accumulated is covered by the ring 10 on the outside and side, the annular support piece 11 on the upper side, and a constant pressure is applied to these particles 7 by the weight thereof. These particles are then conditioned in a crucible to form a porous rigid skeleton, as shown in FIG. 2, during the cooling of the mold 1 by surface melting of the coating 8 to form the coating 8. Heated to the sintering temperature of the metal or alloy.

As shown in FIG. 4, instead of using the diamond particles 3 pre-covered by the metal coating 8, the cobalt, iron, in proportions of 1 to 15%, preferably 3%, to the metal powder volume Mixtures of, bronze and / or nickel powders and diamond particles may be used. The mixture is then poured into the annular cavity 9 of the mold 1 and heated until part or surface melting of the powder is obtained. The powder is sintered under the weight of the support piece 11 to become a porous object.

3 shows an enlarged view of the sintered powder 8 which surrounds the diamond particles 3 evenly dispersed in the powder.

As shown in FIG. 4, in the case of the structure of the particle 9 obtained by sintering and as obtained in the premixing and sintering of the diamond particles and powder, as shown in FIG. 3, the diamond particles are positioned three-dimensionally and It is possible to obtain a structure in which the cavities 12 are more or less uniformly arranged therebetween.

Example

This embodiment relates to the manufacture of a stone cutting disc of diameter 200 mm, thickness 3.5 mm, which can be used in a dry saw, ie without angle cooling, for a portable saw ("angle grinder").

Diamond particles having a particle size between 20-80 mesh (ANSI B74-16) were premixed with 1.5 micron particle size cobalt powder in a 3% ratio to this particle volume. The resulting mixture is placed in an annular cavity 9 of a first mold (FIG. 1) of refractory steel 3.5 mm deep and 1.25 cm wide to obtain a annular band of constant thickness. This band is subjected to a constant pressure through a support piece 11 weighing 4 kg.

In the next step, the mold is heated to 800 ° C. for 30 minutes in a nitrogen atmosphere so that the powder is sintered to form a porous structure.

After release of the mold, the annular structure shows that the pores with an average diameter of 300 microns and a maximum diameter of 1 mm are uniformly dispersed with 60% porosity.

The structure 2 thus obtained is located in the second mold 4 as shown in FIG. It is a permanent mold made of refractory steel for casting liquid metals or alloys under gravity. This metal is formed from a 7% silicon 3% copper addition aluminum-silicon alloy with a melting point of about 600 ° C. About 25 kg of this alloy is melted in an electric furnace at a temperature of about 670 ° C. and deoxidized and purified to lower the content of oxides and hydrogen in order to obtain as fine grained particles as possible during solidification in the mold 4. This alloy is a 1 kg crucible (not shown) through a 50 mm diameter nozzle 13 fixed in the center of the mold to ensure penetration into the cavity of the diamond-embedded structure 2 and complete filling of the mold. Is injected into the middle of the mold 4.

The mold 4 was maintained at 250-350 ° C. and lubricated prior to casting by known silicone-containing mold release agents.

The alloy filled the mold 4 at a rate of 300 g; The remaining, ie 700 g, is held in the nozzle 13 and is pressured by the amount of alloy injected into the mold. After solidification, the nozzle 13 containing the remainder of the alloy, referred to as the "dead head," is cut apart from the abrasive disc obtained upon release of the mold. Mold release is performed when the component temperature drops to about 150 ° C., and FIG. 6 shows this demolition component. At this time, when the component reaches room temperature, it is finished by milling, and as shown in Fig. 7, a 30 mm through hole 14 is drilled along the axis thereof.

Finally, the diamond-embedded annular structure of the machined abrasive disc is subjected to a surface treatment by polishing such that the diamond particles are partially exposed, as shown in FIG.

By means of a particular embodiment of the invention, a single mold 4 is used, which can rotate about its axis, as shown in FIG.

Through or through the axis or center, while the particles of the electro-coated diamond particles, whether or not sintered, are rotated about the axis at a speed sufficient to move these particles into the annular cavity 19 by centrifugal force in the mold circumferential direction, In particular it is introduced into the mold 4 via the nozzle 13.

As mentioned, in a later step, the material 5 forming the support 6 is introduced into the mold 4 in the liquid phase through an axis or center, and also the liquid material 5 is moved towards the circumference by centrifugal force It is rotated at a sufficiently high speed to penetrate into the cavity 12 between the particles or sintered bodies of the particles.

After this operation, the mold is cooled to solidify the material 5 and a rigid support is formed which is fixed to the particles surrounding the diamond particles and extends from the support circumference to form the diamond-embedded structure 2.

Finally, the diamond embedded disk thus obtained is removed from the mold.

It should be noted that the diameter of the diamond embedded structure 2 can be varied within a relatively wide range.

Nevertheless, in the case of stone cutting discs, 2.5 mm-1.75 cm width, 2.5-3.7 mm (0.1-0.15 ") thickness is preferred, depending on the required life of the tool.

An advantage of the method according to the invention is that, unlike the known method, when a diamond embedded structure is attached to the support, no pressure is applied to the structure. This advantage greatly reduces the cost of making diamond embedded tools.

In addition, the diamond-embedded structure is the same metal used to secure the support to the support, in particular the alloy, which constitutes the support itself, thus preventing any tension between the structure and the support.

In some cases, it may also be useful to reinforce the support 6 of the tool by embedding a metal lattice 15 in the abrasive tool, as shown in FIG.

The abrasive tool may also consist of a drill as shown in FIG. 10, a polishing wheel as shown in FIG. 11 or a cable showing abrasive blocks at regular intervals along the circumference. These blocks constitute a small cylindrical abrasive tool that is provided with a cylindrical wall, for example the same structure as a diamond-embedded disc. The technique used to make these three types of abrasive tools is the same as when making discs, as in FIG. 5 or as described above.

In practice, it is sufficient only to modify the size and shape of the mold used.

Also, in some cases, the porosity of the diamond-embedded structure 2 may not be uniform, for example in the zero porosity of the end region opposite the support, this zero porosity is also intermediate between the end region and the vicinity of the support. The average porosity of the region and the maximum porosity of the last region may range.

The porosity of the intermediate region is 10-30%, the porosity of the structure region near the support is 30-70%, so that an effective connection between the structure and the support is obtained.

The area near the support may be, for example, one quarter or one half of the total volume of the diamond-embedded structure, and the end and intermediate areas may be formed to have the same volume, for example.

However, these areas can also vary in porosity from one area to the next. That is, the porosity gradient may be generated in each region. For example, in the middle region, the end region side may have the minimum porosity and the support region region side may be the maximum.

In another embodiment of the diamond-embedded structure according to the invention, the positioning of the diamond particles can be carried out by a 1-5 mm diameter sieve made of steel, bronze or synthetic fibers, for example.

Finally, the diamond-embedded structure may have a grooved shape such that the strength coupled to the support to the structure may be raised by at least partially filling the surface grooves of the structure.

The abrasive portion present in the diamond-embedded annular structure can vary greatly depending on the intended use of the abrasive tool, but this ratio is preferably 1-15% of the body volume of the casting, as already mentioned.

It is to be understood that the present invention is not limited to the above-described embodiments and that various modifications may be made without departing from the scope of the present invention.

Claims (10)

In abrasive tools for cutting, drilling, grinding, etc. comprising a structure 2 in which diamond particles are located and fixed to the circumference of the support 6, the structure 2 is at least in the region near the circumference of the support 6. A skeleton shape having pores 12 open outwardly and occupying at least 30-75% of the volume density of the region, the mean diameter of the pores 12 being 100-500 microns, up to 2 mm, and the support 6 ) Is an abrasive tool, characterized in that it consists of a metal or an alloy (5) that penetrates into at least 70% of the cavity 12 and has a melting point of above the tool's service temperature and below 950 ° C. 2. An abrasive tool according to claim 1, characterized in that the support (6) is based on one of the alloys of these elements, such as zinc, tin, aluminum, magnesium or copper or alloys comprising silicon. 3. Abrasive tool according to claim 2, characterized in that the support (6) is formed of an aluminum-silicon alloy comprising 5-9%, preferably 7% silicon. 4. The structure according to one of the preceding claims, wherein the structure (2) consists of particles (7) formed from diamond particles coated with a metal coating (8), which particles are attached three-dimensionally by sintering. Polishing tools. 5. The abrasive tool according to claim 1, wherein the structure (2) comprises 1-15%, preferably 3% by volume of diamond particles in a skeleton based on cobalt, iron, brass or nickel. 6. An abrasive tool as claimed in one of claims 1 to 5, characterized in that other abrasive particles are added to the skeleton (2) comprising diamond particles (3) at a rate not more than 10 times the amount of diamond particles (3). In the method of manufacturing an abrasive tool according to any one of claims 1 to 6, which comprises a structure 2 in which the diamond particles are located and fixed to the circumference of the support 6, the diamond particles 3 are annular in the mold 4. Spaced three-dimensionally apart from each other in accordance with (2), wherein the support is at least somewhat uniformly spaced between the diamond particles (3) so as to occupy 30-75% of the body volume of this area in the area of the structure near the support (6). 12) is formed on the annular structure (2) to be dispersed, forming a support (6), the metal or alloy having a melting point of more than the tool's working temperature and below 950 ℃ cast in the mold (4) in the liquid phase The alloy 5 is introduced into at least 70% of the cavity 12, and then the metal or alloy 5 solidifies so that the annular structure 2 and the support 6 on which the diamond particles 3 are located. This way a uniform connection manufacture abrasive tool featuring formed. 8. The annular structure (2) in which the diamond particles (3) are located is first formed in the first mold (1), and then the structure (2) is placed in the second mold (4) to form the structure (2). A metal or alloy (5) introduced into the cavity (12) and forming a support (6) in a liquid phase. 9. A particle (7) according to claim 8, wherein a particle (7) consisting of diamond grains (3) coated with a metal film (8) is introduced into the first mold (1) to form an annular structure (2). It is sintered to form a framework 2 which occupies 30-75% of the cavity 12, which is then placed in the second mold 4 to penetrate into the cavity 12 of this framework 2. A method in which a metal or alloy (5) is cast into which the support (6) is formed in the sun. 9. The method according to claim 8, wherein in order to form the annular structure (2), the diamond particles (3) are first mixed in a proportion of 1-15% of the volume of the diamond particles, and the cobalt powder is mixed with the preferred metal powder (8). It is introduced into the mold 1 and sintered with the diamond particles 3 surrounded by these powders 8, so that the particle size of the powders 8 is such that the structure 2 after the sintering occupies 30-75% of the cavity 12. Selected method.