JPH11309711A - Diamond saw blade and production of diamond whetstone used for it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure strength of a chip main body and to improve durability while excellent sharpness is kept by embedding a filling material into at least one slit provided along the circumferential direction of an integrally bonded diamond whetstone on the apex of a metal base. SOLUTION: A diamond whetstone is formed on the apex of teeth 4a of a metal base 4 through a substrate layer 3 and a slit 2 provided on a mixed layer 1 of diamond abrasive grain and a bond for forming a whetstone and a filling material 5 embedded therein reinforce a thin part to hold necessary strength of the whole and to prevent the whetstone part from being broken or cracked. The edge area of the whetstone is decreased to obtain high cutting speed and stable whetstone life in parallel and the filling material 5 is gradually abraded during cutting and the apex of the embedded part of the filling material 5 is kept into a little recessed shape from the apex face of the whetstone and the edge part of the slit 2 and the abrasive grain projected from the surface of the edge of the mixed layer 1 of the bond and the diamond abrasive grain effectively bite a material to be cut and guarantee excellent sharpness for a long time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a diamond which, when subjected to grinding or cutting for hard and brittle materials typified by concrete or stone, exhibits excellent sharpness and can realize a long tool life. The present invention relates to a saw blade and a method for producing a diamond grindstone used therein.

[0002]

2. Description of the Related Art As a tool used for grinding and cutting hard and brittle materials such as stone materials and concrete structures,
Conventionally, a diamond saw blade has been widely used.
These diamond saw blades are generally called diamond chips (hereinafter referred to as “chips”), which are collectively referred to as chips or segments formed by a diamond base, a bond, and a metal base called an underlayer at the tip of a disk-shaped metal substrate. Is mounted, and grinding or cutting is performed by a mechanism for cutting hard and brittle material through rotation of the disk-shaped metal substrate (hereinafter sometimes referred to as “blade”).

An ideal condition for a diamond saw blade powered by a rotary tool to exhibit sharp sharpness when cutting hard and brittle materials such as concrete is a rotary tool for applying power. Power, the minimum required number of diamond abrasive grains corresponding to the peripheral speed of the blade accompanying the power, with a sharp edge, protrude more from the tip of the bond holding the diamond abrasive grains, In addition, while maintaining that state for as long as possible, it cuts into the work material, destroys it, and discharges it as chips at high speed.

On the other hand, in order to improve the sharpness of the diamond saw blade, it is necessary to minimize the area of the tip of the tip which comes into contact with the work material and to improve the penetration of the tip abrasive grains into the work material. is there. In this case, in order to secure the required number of tip abrasive grains, it is necessary to increase the concentration of the diamond with respect to the bond (hereinafter, may be referred to as an “outlet”).

As described above, if the tip area of the tip is made extremely small and the diameter of the diamond outlet is increased more than necessary in order to improve the sharpness, the absolute volume of the bond portion becomes small, which affects the strength of the whole diamond grindstone. Therefore, there is a problem that it is not desirable. If the grindstone part is greatly ground, the life of the diamond saw blade will be there, and even if a small chip is generated, the grinding part will be severely worn in the processing work immediately after that, resulting in a stable life performance. It was difficult to demonstrate.

[0006]

As described above, in order to improve the sharpness of the diamond saw blade, high quality diamond abrasive grains are used, and the area of the cutting edge at the tip end is designed as small as possible. It is desired to increase the outlet of diamond abrasive for
Reducing the cutting edge area at the tip of the tip and increasing the outlet of the diamond grindstone for the bond
As a result, the absolute volume of the bond that serves as a bonding material while holding the diamond abrasive grains is reduced, so that there remains a problem that the life performance of the entire diamond grindstone constituting the chip is impaired.

Further, as a means for improving the sharpness of the diamond saw blade, the tip is made thinner in order to reduce the cutting edge area at the tip end as described above. The number of chips welded to the outer surface of the saw blade is reduced to reduce the chip ratio. Make a specific notch (slit) in the chip. These three means are conceivable, and are known as conventionally known means.

However, the thinning of the tip requires the thinning of the blade itself, which causes lateral runout during rotation and significantly impairs the cutting accuracy. It is difficult to secure rigidity. In the method of reducing the number of chips, the load per chip during processing is extremely increased, causing uneven wear of the chip due to impact, and the durability thereof is significantly reduced. Furthermore, the above-mentioned method of forming a notch such as a groove in the chip is difficult in design because the durability of the chip body is impaired when the thickness of the grindstone portion is extremely thin, and furthermore, a deep groove is provided in the chip. This is a significant hindrance in efficiently manufacturing chips, and significantly increases the cost of chips.

The present inventors have conducted intensive studies to solve the various problems left in the above prior art, and as a result, a reinforcing means is provided in a slit provided to reduce the area of the diamond grindstone at the tip of the tip. It has been found that by shifting, the durability of the chip body can be improved while maintaining the strength of the chip body and maintaining excellent sharpness, and the present invention has been completed.

[0010]

According to the present invention, there is provided a diamond saw blade having a structure in which a metal substrate and a diamond grindstone are integrally connected to a tip of the metal substrate. So,
The main structural feature is that a filler is buried in at least one slit provided along the circumferential direction of the diamond grindstone. Further, as a method of manufacturing a diamond grindstone used for the diamond saw blade, a plurality of diamond layer primary compacts in which a metal bond and a diamond abrasive grain, which are raw materials of a diamond grindstone portion, are mixed at a predetermined ratio, are prepared in advance. While sandwiching a plate-shaped filler material processed to a predetermined size, the primary molded body of the underlayer similarly processed to a predetermined size is set in a sintering mold in a form of abutting, and then pressure-sintered. Thus, an integrated structure of a diamond grindstone having a slit can be obtained without any post-processing by a structural feature.

In a preferred aspect of the present invention, it is desired that the filler buried in the slit is made of a material which is more easily worn than a diamond grindstone, has a low coefficient of thermal expansion, and has a certain degree of mechanical strength. . Specifically, carbon-based materials such as carbon, graphite, and carbon fiber, mica, molybdenum disulfide, porous ceramics,
It is appropriately selected from a Pb-Cu-based solid lubricant, a sintered metal powder, a mixture thereof, and the like.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In order to obtain good sharpness by a diamond saw blade, it is necessary to reduce the tip area ratio of the diamond grindstone portion and increase the diamond outlet as described above. In other words, reducing the tip area makes it easier for the tip diamond to bite into the work material.On the other hand, when the area ratio is reduced, in order to secure the required number of tip abrasive grains, It is necessary to increase the outlet.

However, the tip area is reduced, and
Increasing the diamond outlet means that the proportion of the metal bond in the grindstone decreases at the same time, and as a result, the strength itself as the grindstone portion decreases.

However, according to the structure of the present invention in which the filler is buried in the slit provided along the circumferential direction of the diamond grindstone by the above means, the filler fills the thin portion of the grindstone. As a reinforcing material, the required strength of the entire grindstone portion is maintained, and chipping and cracking of the grindstone portion can be prevented. That is, with this structure, it is possible to obtain both a high cutting speed and a stable grinding wheel life. The number of the slits is preferably at least one for one chip, and the number of slits is not limited to two or more if necessary.

By the way, the cutting chips generated during cutting are smoothly discharged to the outside of the rear system through the driving force generated by the centrifugal force due to the rotational movement, and the phenomenon of stagnation and interposition on the cutting edge surface is effectively prevented. At the same time, the filler buried in the slit of the diamond grindstone wears gradually and appropriately during cutting, and as the cutting work progresses, the filler buried part always maintains a shape that is slightly depressed from the tip of the grindstone. The wear of the filler buried portion progresses along with the wear of the portion.

[0016] These effects are brought about by the fact that the filler having brittleness and moderately high wear properties is embedded in the slit of the grindstone portion, so that both the improvement of the grindstone strength and the excellent sharpness are achieved. Things. Therefore, the substance to be filled into the slit is a substance other than the filler of the present invention,
For example, in the case of a metal with high bending strength and low abrasion, it can reinforce the grindstone, but the work material directly hits this metal surface, which becomes the cutting resistance and cannot exert a high cutting speed .

The method for producing a diamond grindstone for a diamond saw blade according to the present invention comprises the steps of: providing a diamond bond between a plurality of diamond layer primary compacts in which a metal bond as a raw material of a diamond grindstone portion and diamond abrasive grains are mixed at a predetermined ratio; While sandwiching a plate-like filler processed in advance to a predetermined size, the base layer primary molded body also processed in advance to a predetermined dimension is set in a sintering mold in a form of abutting, and then pressure-sintered. The object of the present invention is to obtain a diamond whetstone integrated structure having a slit without any post-processing. According to the above-described method, it is not necessary to perform secondary processing such as electric discharge machining after sintering as in the conventional example in which a slit space is provided in the grindstone portion, and it is possible to obtain an integrated structure as the grindstone portion after sintering. In this respect, the production method of the present invention is a method excellent in mass productivity.

The filler used in the present invention may be a commercially available carbon-based material such as carbon, graphite, or carbon fiber, mica, molybdenum disulfide, porous ceramics, or the like.
A compact having a higher wear resistance and a lower coefficient of thermal expansion than a diamond grindstone, such as a Pb-Cu solid lubricant, a metal powder sintered compact, and a mixture thereof, can be appropriately selected and used. It is preferable that the width of the material spacer is increased in accordance with the width of the diamond grindstone within a range of 0.2 mm or more. If the width of the filler spacer is less than 0.2 mm, the slit provided in the diamond grindstone does not act sufficiently and the cutting speed is significantly reduced.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing a periphery of a tip portion of a diamond saw blade according to an embodiment of the present invention,
FIG. 2 is a sectional view taken along line XX of FIG. In the drawing, a chip 10 is formed by forming a diamond grindstone (mixed layer 1) at the tip of one tooth 4a of a metal substrate 4 with a base layer 3 interposed therebetween. That is, the slit 2 provided in the mixed layer 1 of the diamond abrasive grains and the bond constituting the diamond whetstone and the filler 5 embedded in the slit 2 serve to reinforce the thinned portion of the whetstone, As a result, the required strength of the entire grindstone portion is maintained, and chipping or cracking of the grindstone portion can be prevented. That is, according to this structure, the cutting edge area of the diamond grindstone can be reduced, and both a high cutting speed and a stable grindstone life can be obtained.

At the same time, the diamond wheel tip 1
The filler 5 buried in the 0 slit 2 wears gradually and appropriately during cutting, and with the transition of the cutting operation, the tip of the filler buried portion always keeps a shape slightly depressed from the whetstone tip surface. The wear of the filler buried portion proceeds prior to the wear of the grindstone portion. Therefore, the edge portion of the slit 2 and the diamond abrasive grains protruding from the surface of the cutting edge of the mixed layer 1 of the bond and the diamond abrasive grains effectively penetrate into the work material to ensure excellent sharpness over a long period of time.

FIG. 3 shows another form of the chip, in which three slits 2 are formed along the circumferential direction of the diamond grindstone.
a, 2b, and 2c are formed, and the filler 5 is embedded in the slit. FIG. 4 shows another embodiment of the chip. In the chip 10, small chips 7a to 7d are arranged in a zigzag pattern, and slits 2 are formed in the small chips 7a to 7d, respectively.
a to 2d are formed. The chips shown in FIGS. 3 and 4 have the same effects as those shown in FIG.

[0022]

EXAMPLES Hereinafter, the present invention will be described with reference to Examples and Comparative Examples.
This will be described more specifically.

Example 1 A 0.87 mm-thick graphite plate (MC-5 manufactured by Mechanical Carbon Co., Ltd.) was sandwiched between and adjacent to a diamond layer primary compact formed by mixing and molding a tungsten bond and diamond abrasive grains. Then, the diamond grindstone obtained by charging the sintering mold in such a manner that the primary molded body for the underlayer is set and sintering under pressure is set to an outer diameter of 2 mm.
A diamond saw blade having a structure as shown in FIGS. 1 and 2 was prepared by welding to the tip of a steel substrate having a thickness of 86 mm and a thickness of 2.0 mm. Next, the diamond saw blade was mounted on an engine cutter (displacement: 85 cc),
Rotating at 5,000 rpm, dry cutting of concrete board (age: 1 year, aggregate particle size: 20 mm, board thickness: 60 mm) was attempted. No cutting occurred, and continuous cutting could be performed in a dry manner without using cooling water or cutting water. The average cutting speed at this time was 1200 mm / min, and it was confirmed that a cutting operation of 150 m was possible before the grindstone portion of the saw blade was completely worn.

Example 2 A diamond grindstone as shown in FIGS. 1 and 2 was formed using the same grammar as in Example 1 except that mica ceramics was used in place of graphite. A diamond saw blade having the same structure was made. Next, cutting was attempted under the same conditions as in Example 1. As a result, there was no occurrence of blurring of the substrate or uneven wear of the chip, and dry cutting could be continuously performed without using cooling water or cutting water. The cutting speed at this time was 110 mm /
min, and it was confirmed that a cutting operation of 170 m was possible before the grinding portion of the saw blade was completely worn.

[0025]

As is clear from the examples and comparative examples,
The diamond saw blade according to the present invention is characterized in that at least one slit provided in the diamond grindstone in the circumferential direction of the diamond grindstone has a filler made of a heat-resistant material which is more easily worn than the diamond grindstone and has a small coefficient of thermal expansion. By embedding, even if the tip area of the tip in contact with the workpiece is reduced, the reinforcing effect provided by the filler guarantees a sharp tool sharpness and a stable tool life.

Further, in the method for manufacturing a diamond grindstone according to the present invention, the slit provided in the grindstone portion formed by the metal bond and the diamond abrasive grains is formed into a predetermined size between a plurality of diamond layer primary compacts in advance. It is formed by sintering under pressure after setting the plate-shaped filler in the form of sandwiching it, so that post-processing such as electric discharge machining is not required, and an integrated structure of diamond grinding stone Thus, mass production of diamond grinding stones can be performed extremely efficiently and at low cost.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a part of a diamond saw blade according to the present invention.

FIG. 2 is a cross-sectional view taken along line XX of FIG.

FIG. 3 is a perspective view showing another embodiment of the tip portion of the diamond saw blade according to the present invention.

FIG. 4 is a perspective view showing another form of the tip portion of the diamond saw blade according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Mixed layer of diamond abrasive grains and bond 2 2a, 2b, 2c, 2d, slit 3 Underlayer 4 Metal substrate (base metal) 5 Filler 10 Chip

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI B24D 5/12 B24D 5/12 Z 5/14 5/14 (72) Inventor Shigeyoshi Kobayashi 1770 Hongo, Ebina-shi, Kanagawa Prefecture Sankyo Diamond Industrial Co., Ltd.

Claims (4)

[Claims] 1. A diamond saw blade having a structure in which a diamond grindstone is integrally joined to a tip of the metal substrate, wherein at least one slit is provided along a circumferential direction of the diamond grindstone. Characterized in that a filler is embedded therein. 2. The diamond saw blade according to claim 1, wherein the filler buried in the slit is made of a heat-resistant material that is more easily worn than the diamond grindstone and has a small coefficient of thermal expansion. 3. The filler is selected from the group consisting of carbon-based materials such as carbon, graphite, and carbon fibers, mica, molybdenum disulfide, porous ceramics, Pb-Cu-based solid lubricants, and sintered metal powders. 3. The diamond saw blade according to claim 1, which is a mixture of two or more kinds. 4. A plate-like filler previously processed to predetermined dimensions is sandwiched between a plurality of diamond layer primary compacts in which metal bonds and diamond abrasive grains are mixed at a predetermined ratio, Similarly, after setting the underlayer primary molded body that has been processed to a predetermined dimension in advance in a form in contact with the mold for sintering, by pressure sintering, an integrated structure of a diamond grinding stone having a slit without post-processing is formed. A method for producing a diamond grindstone for a diamond saw blade, comprising: