JP3411233B2 - Manufacturing method of grinding tool - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a diamond abrasive grain,
The present invention relates to a grinding tool using super-abrasive particles such as CBN abrasive particles, and particularly relates to a grinding tool having improved abrasive particle holding force and a method for manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, a grinding tool in which superabrasive grains such as diamond grains and CBN grains are fixed to a base metal by a brazing method has been used for grinding and polishing. Such a grinding tool is required to have excellent sharpness and to maintain the sharpness stably over a long period of time. However, whether it is a diamond abrasive grain or a CBN abrasive grain, the sharpness and the life are shortened as the grinding work progresses. The main cause is that the abrasive grains come off due to insufficient strength of the brazing material.

As a countermeasure against the loss of abrasive grains, Japanese Examined Patent Publication No.
22194 discloses that at least 50% by weight of one or two metals selected from the group consisting of Ni and Co,
It is disclosed to use a brazing alloy containing 2 to 26% by weight of Cr and 12% by weight or less in total of one or more elements selected from the group consisting of B, Si and P.

Further, Japanese Laid-Open Patent Publication No. 3-131475 discloses a method in which a coating material obtained by mixing a metal forming a carbide, a brazing material and a temporary binder is applied to a tool base, and diamond particles are applied on the coating material to perform brazing. Has been done.

Further, in Japanese Patent Laid-Open No. 10-175156, at least one selected from Ti, Cr, and Zr is used.
Using an alloy having a melting point of 650 ° C. to 1200 ° C. containing 5 to 20% by weight, diamond particles are brazed on a supporting member made of a metal and / or an alloy in a single layer, and Ti, Cr is applied to the boundary between the diamond particles and the alloy. Alternatively, it is disclosed that a carbide layer of a metal selected from Zr is formed.

[0006]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
According to the method described in Japanese Patent No. 2194, a brazing alloy of a type mainly containing Co and / or Ni containing a specific amount of Cr easily wets the surface of diamond to obtain a strong bond to the base material of diamond. It is supposed to be.
Further, according to the method described in JP-A-3-131475, it is said that the carbide and brazing filler metal layers rise up on the side surfaces of the diamond particles in the heating step, thereby increasing the strength of the tool. In addition, JP-A-10-1
According to the method described in Japanese Patent No. 75156, a carbide layer of one or more metals selected from Ti, Cr or Zr is formed at the interface between diamond and a brazing alloy,
It is said that the bonding strength will increase.

However, even by the methods described in the above publications, the brazing material is only partially chemically bonded to the surface of the diamond abrasive grains, and the abrasive grain retaining force is still insufficient. In addition, a low melting point metal containing Ag, Cu, and Ni as main components is generally used as a brazing material, and since these materials have poor wear resistance, these materials are worn by cutting chips and the like, and As a result, the holding power of the grains is reduced, and the grains fall out.

Further, as another method for increasing the holding force of the abrasive grains, there is a method described in JP-A-10-264034. According to this method, it is said that the holding force of the abrasive grains after brazing can be enhanced by coating the periphery of the abrasive grains with a binder containing a specific active powder component. However, this method has a problem in that the tip of the abrasive grains, a so-called cutting point, is coated with the binder, so that it is difficult to act as a sharp cutting edge, and as a result, the grinding ability is reduced.

An object of the present invention is to improve the holding power of abrasive grains in a grinding tool in which abrasive grains are fixed to the surface of a base metal by a brazing method without operating the components of the brazing filler metal and without lowering the grinding ability. It is to provide the means to make.

[0010]

The grinding tool of the present invention is a grinding tool using abrasive grains such as diamond and CBN, and the abrasive grains formed by surface recesses or through holes alone or in combination are used as a base metal. One layer or a plurality of layers are provided on the base metal, and the recesses or through holes of the abrasive grains are filled with a brazing material containing an active metal, and the abrasive grains are brazed on the base metal.

In the grinding tool of the present invention, by forming recesses or through holes in the surface of the abrasive grains in advance,
When the abrasive grains are brazed to the base metal, these recesses and through holes are filled with the brazing filler metal, the contact area between the abrasive grains and the brazing filler metal is increased, and the abrasive grain holding force is remarkably increased.

It is difficult to form recesses or through holes on the surface of the abrasive grains by machining because the hardness of the abrasive grains is extremely high. Grains are easy to crush.
It is also possible to chemically react the surface to form microscopic unevenness, but the abrasive grains themselves deteriorate. Therefore, laser irradiation is the most suitable method for processing the abrasive grains without lowering the strength of the abrasive grains and without crushing the abrasive grains.

The formation of recesses and through holes on the surface of the abrasive grains by laser irradiation can be carried out as follows. As shown in FIG. 4, first, the holes H each having a size in which the abrasive grains 1 are inserted one by one.
Abrasive grains 1 on the punching plate P _{1 in} which ₁ is regularly arranged
To fill. From above, a hole H having a diameter smaller than that of the abrasive grain 1
_An abrasive grain 1 is fixed by placing a punching plate P _{2 in} which ₂ are regularly arranged. In this state, the abrasive grain position is irradiated with a laser by numerical control to form a through hole 2 or a recess (not shown) in the abrasive grain 1. In particular, when a YAG laser is used as the laser, fine holes with a diameter of several 100 μm can be formed with a high aspect ratio of 5
It can be formed with 0 or more, thermal influence is small, and deterioration of abrasive grains is small.

Here, since the holding power of the abrasive grains increases as the portion where the brazing material can be filled in the recesses and the through holes increases, the through holes are preferable to the recesses in this respect.
However, the larger the number of through holes, the easier the abrasive grains are crushed. Therefore, it is better to limit the number of through holes to one or two. For low-strength abrasive grains for which it is difficult to form through-holes, recesses may be uniformly formed on the surface of the abrasive grains.

Abrasive grains having the above-mentioned recesses and through holes are formed in a single layer or a plurality of layers on a base metal and brazed. Whether to dispose the abrasive grains in one layer, two layers, or three or more layers can be determined depending on the application of the grinding tool. For example, one layer is suitable when the accuracy of the machined surface is important, two layers are suitable when both the accuracy of the machined surface and the tool life are required, and three layers are important when the tool life is emphasized. The above multilayers are suitable. The brazing method can be performed by a conventionally known method, and a method of incorporating an active metal into the brazing material can also be adopted.

When brazing the abrasive grains, the thickness of the brazing material is preferably 10% or more of the grain size of the abrasive grains. If the thickness of the brazing material is less than 10% of the grain size of the abrasive grains, the effect of increasing the adhesion force of the abrasive grains becomes small. On the other hand, if the thickness of the brazing filler metal is too large and the protrusion amount of the abrasive grains becomes small, the sharpness decreases, so the thickness of the brazing filler metal is set so that the protrusion amount of the abrasive grains becomes 20% or more of the abrasive grain diameter. It is desirable to do.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below based on an embodiment in which the present invention is applied to a cup type rotary grindstone used for grinding an aluminum alloy or the like. FIG. 1 is a view showing a rotary grindstone which is an embodiment of the present invention, in which (a) is a plan view and (b) is a front sectional view. FIG. 2 is a partially enlarged sectional view of an abrasive layer of the rotary grindstone of FIG.

The rotary grindstone 10 is formed by continuously attaching to the outer peripheral edge 11a of the cup-shaped base metal 11 an annular abrasive layer 12 using the diamond abrasive grains 1 and adhering it by brazing. The base metal 11 is a base metal having a short overall shape, and has a mounting hole 11b for mounting on a rotating shaft of an electric tool at the center of the bottom. The dimensions of each part of the grindstone are the outer diameter of the base metal 11 being 100 mm, the radial width of the abrasive layer 12 being 8 mm, and the total height of the base metal 11 being 30 mm.

As shown in FIG. 2, the abrasive grain layer 12 has grooves 3 formed on the surface of the diamond abrasive grain 1 having a grain size of about 0.35 to 0.40 mm (# 40 to # 50) and penetrates inside. The holes 2 are formed, and the diamond abrasive grains 1 are used to form the outer peripheral edge 11 of the base metal 11.
One layer is provided on a, the groove 3 and the through hole 2 are filled with a brazing material 14 containing an active metal, and the diamond abrasive grains 1 are brazed on the outer peripheral edge 11a of the base metal. The opening width of the groove 3 is 0.1 to 0.2 mm, the depth is 0.1 to 0.3 mm, the number is 2 to 3, and the inner diameter of the through hole 2 is 0.1 to 0.2 m.
m, the number is 1 to 2. Diamond abrasive grain 1 groove 3
The through hole 2 and the through hole 2 are formed by irradiating a YAG laser by the method shown in FIG.

The brazing material 14 comprises Ti, V, and
This is an active silver solder containing Cr, and after the brazing material 14 is uniformly applied on the base metal 11, the diamond abrasive grains 1 are arranged and heated to bring the diamond abrasive grains 1 to the outer peripheral edge of the base metal in the state shown in FIG. It adheres on 11a. Here, the thickness of the brazing material 14 is
The amount of protrusion of the diamond abrasive grains 1 is set within a range of 10 to 80% of the abrasive grain diameter so that the protrusion amount of the diamond abrasive grains 1 is 20% or more of the abrasive grain diameter while securing the fixing force of the diamond abrasive grains 1.

As described above, the rotary grindstone 10 of this embodiment
Since the groove 3 and the through hole 2 are formed in the diamond abrasive grain 1 in advance, when the diamond abrasive grain 1 is brazed on the outer peripheral edge 11a of the base metal, the brazing filler metal 14 forms the groove 3
And the through hole 2 are filled with the diamond abrasive grains 1 and the brazing material 1.
The contact area with 4 increases and a high abrasive grain holding force is obtained.

[0022]

EXAMPLE A rotary grindstone (invention product) of the present invention shown in FIGS. 1 and 2 and an abrasive grain layer using ordinary abrasive grains having the basic shape shown in FIGS. A grinding test was performed using the above-mentioned rotating grindstone (comparative product). Table 1 shows the specifications of the grindstone used for the test.

[0023]

[Table 1]

[Test conditions] Machine used: Makino universal tool grinder Table speed: 1200 m / min Grinding wheel peripheral speed: 1.5 m / min Depth of cut: 0.1 mm / pass Grinding method: Wet work material: ADC -14 (aluminum die casting alloy)

[Test Results] Inventive products were excellent in the retention of the abrasive grains, did not fall off during the grinding process, and could maintain good sharpness for a long time. On the other hand, the comparative product did not have sufficient retention of the abrasive grains, and a part of the abrasive grains fell off during the grinding process, resulting in a decrease in sharpness. Fig. 3 is a diagram showing the transition of power consumption, which is one of the indicators of the sharpness of the grindstone. The comparative product had a power consumption increase during the grinding and could not be used continuously, whereas the invention product was compared. Stable low power consumption was exhibited even after grinding twice as much as the product, and continuous grinding was still possible.

[0026]

According to the present invention, the following effects can be obtained.

(1) By forming recesses or through holes in the surface of the abrasive grains in advance, when the abrasive grains are brazed to the base metal, the brazing material is filled in these recesses or through holes,
The contact area between the abrasive grains and the brazing material is increased, and the abrasive grain holding force is remarkably increased. As a result, the abrasive grains do not fall off during the grinding process, and good sharpness can be maintained for a long time.

(2) By forming the recesses or through holes on the surface of the abrasive grains by laser irradiation, it is possible to form the recesses or through holes on the surface of the abrasive grains without causing deterioration or crushing of the abrasive grains. In particular, by using the YAG laser, it is possible to form fine holes without causing deterioration of the abrasive grains due to the influence of heat.

[Brief description of drawings]

FIG. 1 is a diagram showing a rotary grindstone which is an embodiment of the present invention, in which (a) is a plan view and (b) is a front sectional view.

FIG. 2 is a partially enlarged cross-sectional view of an abrasive material layer of the rotary grindstone of FIG.

FIG. 3 is a graph showing a grinding test result.

FIG. 4 is an explanatory diagram of abrasive grain processing by laser irradiation.

[Explanation of symbols]

1 abrasive grain 2 through holes 3 grooves 10 rotating whetstone 11 money 11a outer peripheral edge 11b Mounting hole 12 Abrasive layer 14 Brazing material

─────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-8-325558 (JP, A) JP-B-49-10968 (JP, B1) (58) Fields investigated (Int.Cl. ⁷ , DB name) B24D 3/00 B24D 3/06

Claims (2)

(57) [Claims] 1. An abrasive grain such as diamond or CBN is used.
The method of manufacturing a grinding tool
Abrasive grains with surface grooves or through holes individually or in combination
Formed, and disposing these abrasive grains on the base metal in one or more layers,
Fill the surface groove or through hole of the abrasive grain with a brazing material and grind
Of a grinding tool characterized by brazing grains on a base metal
Production method. 2. A YAG laser is used as the laser.
The method for manufacturing a grinding tool according to claim 1, wherein