JP7550688B2 - Manufacturing method of single layer hybrid bond grinding wheel - Google Patents

Description

The present invention relates to a single-layer hybrid bond grinding wheel and its manufacturing method.

Figure 4 of Patent Document 1 discloses a typical single-layer metal bonded grinding wheel. This single-layer metal bonded grinding wheel comprises a substrate, a metal bond layer, and numerous abrasive grains. The metal bond layer is metallic and is provided on the substrate by electrochemical deposition or the like. Each abrasive grain is fixed in a single layer to the substrate by the metal bond layer with its surface exposed.

For example, this single-layer metal bonded grinding wheel is embodied as a grinding tool and used during grinding processing. In this case, since the metal bond layer of the single-layer metal bonded grinding wheel is made of a tough metallic material, the individual abrasive grains are less likely to fall off, and the wheel exhibits high durability.

JP 2002-160168 A

However, in single-layer metal bonded grinding wheels, the metal bond layer and each abrasive grain are generally fixed to the substrate by electrochemical deposition using a plating solution containing abrasive grains, which inevitably results in a high surface density of abrasive grains on the grinding surface. This tendency is particularly pronounced when the abrasive grains are fine. For this reason, single-layer metal bonded grinding wheels are prone to clogging and welding on the grinding surface during grinding. In this case, grinding resistance increases with long-term continuous use, and eventually grinding becomes impossible. If attempts are made to frequently remove clogging and welding on the grinding surface to avoid this, the grinding efficiency will decrease.

The present invention was made in consideration of the above-mentioned conventional situation, and the problem to be solved is to provide a single-layer hybrid bond grinding wheel that can achieve high durability and high polishing efficiency.

The single-layer hybrid bond grinding wheel of the present invention comprises a substrate, a bond layer provided on the substrate, and a number of abrasive grains fixed in a single layer on the substrate by the bond layer with the surface exposed,
the bond layer comprises a first bond layer provided on the substrate and a second bond layer provided on the first bond layer;
The first bond layer has a glass matrix and metal particles dispersed in the matrix,
The second bond layer is characterized by being metallic.

The single-layer hybrid bonded grinding wheel of the present invention has a metallic second bond layer on the first bond layer, which holds each abrasive grain with high toughness. Therefore, with this single-layer hybrid bonded grinding wheel, each abrasive grain is less likely to fall off during grinding.

In addition, because the base material of the first bond layer of this single-layer hybrid bonded grinding wheel is vitreous, the ratio of abrasive grains in the composition that forms the vitreous can be adjusted as desired, and the surface density of the abrasive grains on the substrate can be reduced as desired. As a result, this single-layer hybrid bonded grinding wheel has a lower surface density of abrasive grains on the grinding surface than conventional grinding wheels, so even when used continuously over a long period of time, clogging and welding are less likely to occur on the grinding surface, and grinding resistance is less likely to increase.

In addition, this single-layer hybrid bonded grinding wheel has a strong bond between the metallic second bond layer and the metal particles in the first bond layer, both of which are metallic, and the second bond layer is strongly bonded to the first bond layer.

The method for producing the monolayer hybrid bonded grinding wheel of the present invention includes the steps of: preparing a mixture containing a composition for forming a glassy matrix , a countless number of metal particles, and a countless number of abrasive grains , the volume ratio of the matrix to the metal particles being 5:95 to 90:10 ;
A second step of providing the mixture on a substrate to form a substrate molded body;
a third step of firing the base material compact to form a first bond layer on the base material, the first bond layer including the base material and the metal particles dispersed in the base material, to form an intermediate body in which the abrasive grains are fixed to the base material in a single layer by the first bond layer;
and a fourth step of forming a metallic second bond layer on the first bond layer by electrochemical deposition , the second bond layer bonding with the metal particles to obtain a single-layer hybrid bonded grinding wheel having a surface density of the abrasive grains of 50% or less .

The manufacturing method of the present invention makes it possible to manufacture the single-layer hybrid bond grinding wheel of the present invention.

The single-layer hybrid bond grinding wheel of the present invention can achieve high durability and high grinding efficiency.

FIG. 1 is a schematic cross-sectional view of an intermediate body according to a manufacturing method of the embodiment. FIG. 2 is a micrograph of the surface of an intermediate body according to the manufacturing method of the embodiment. FIG. 3 is a schematic cross-sectional view of a single-layer hybrid bonded grinding wheel obtained by the manufacturing method of the example. FIG. 4 is a micrograph of the surface of the single-layer hybrid bonded grinding wheel obtained by the manufacturing method of the embodiment. FIG. 5 is a micrograph of the surface of the single-layer hybrid bonded grinding wheel obtained by the manufacturing method of the example. FIG. 6 is a micrograph of the surface of a single-layer metal-bonded grinding wheel of a comparative example. FIG. 7 is a perspective view of a grinding tool using the single-layer hybrid bond grinding wheel of the embodiment. FIG. 8 is a perspective view of another grinding tool using the single-layer hybrid bond grinding wheel of the embodiment. FIG. 9 is a perspective view of another grinding tool using the single-layer hybrid bond grinding wheel of the embodiment.

The substrate can be made of various materials as long as it can hold the bond layer and each abrasive grain. As a substrate having rigidity, metals such as iron, SUS, copper, etc., ceramics such as alumina, silicon nitride, silicon carbide, zirconia, mullite, etc., glass, etc. can be used. If a conductive substrate is used, an electrolytic plating method can be used in the fourth step in the manufacturing method of the present invention.

Abrasive grains may be silica, alumina, zirconia, silicon carbide, silicon nitride, mullite, CBN, yttria-stabilized zirconia, diamond, etc. The grain size of the abrasive grains is set in various ways depending on the application of the grinding tool, etc.

As the glassy base material constituting the first bond layer, a slurry or powder of a composition containing a frit such as borosilicate glass can be used, and the slurry or powder can be formed into a molded body on a substrate, the molded body can be dried as necessary, and the composition can be melted and solidified. In the single-layer hybrid bonded grinding wheel of the present invention, since the abrasive grains are merely fixed to the substrate in a single layer, it is preferable that the first bond layer is dense and substantially free of pores.

In the first bond layer, Ni, Co, Cu, Fe, Zn, Sn, Pb, etc., or alloys of these can be used as metal particles dispersed in the base material. The average particle size of the metal particles is preferably 0.01 to 5 μm. If the average particle size of the metal particles is less than 0.01 μm, the bond strength between the first bond layer and the second bond layer is likely to be insufficient, and if the particle size of the metal particles exceeds 5 μm, the first bond layer is likely to crack and the grinding performance of the abrasive grains is likely to be adversely affected.

The metal constituting the second bond layer may be Ni, Co, Cu, Fe, Zn, Sn, Pb, P, or an alloy thereof.

It is preferable that the metal particles and the metallic substance are made of the same metal. In this case, the metallic second bond layer and the metal particles in the first bond layer are more strongly bonded, and the second bond layer is more strongly bonded to the first bond layer.

According to the inventors' test results, it is preferable that the first bond layer has a volume ratio of base material to metal particles of 5:95 to 90:10. If the volume ratio of base material to metal particles is less than 5:95, the first bond layer contains less glass, making it difficult to fix the metal particles in the first bond layer and difficult to hold the abrasive grains to the substrate. If the volume ratio of base material to metal particles is greater than 90:10, the first bond layer contains fewer metal particles, making it easy for the bond strength between the first bond layer and the second bond layer to be insufficient.

In addition, according to the inventors' test results, it is preferable for the surface density of the abrasive grains to be 50% or less. In this case, clogging and welding are less likely to occur on the polishing surface during grinding.

The mixture prepared in the first step of the manufacturing method of the present invention contains a glass-forming composition, a countless number of metal particles, and a countless number of abrasive grains. The composition contains frits and raw materials such as borosilicate glass. The mixture may be a slurry containing the composition, metal particles, and abrasive grains together with a binder resin, a solvent, etc., or may be a powder consisting only of the composition, metal particles, and abrasive grains.

The substrate molded body in the second step is a mixture provided on a substrate. The mixture on the substrate can be formed by coating a slurry, forming a slurry or powder, or the like. In the third step, the substrate molded body is fired to obtain an intermediate body in which a first bond layer is formed on the substrate. The first bond layer has a glassy base material and metal particles dispersed in the base material. That is, the composition in the mixture in the substrate molded body melts to become a glassy base material, and metal particles are dispersed in the base material. In addition, the intermediate body has abrasive grains fixed in a single layer on the substrate by the first bond layer. In the fourth step, an electrodeposition method using a plating solution, a sintering method in which metal powder is sintered to form a second bond layer, or the like can be adopted. The electrodeposition method may be an electrolytic plating method or an electroless plating method.

The fourth step is preferably performed by electrochemical deposition. In this case, it is easy to form the second bond layer on substrates of various shapes and to ensure a long protruding length of the abrasive grains.

The present invention will be explained below using Tests 1 and 2, as well as Examples 1 to 9 and Comparative Examples.

(Test 1)
In Test 1, the volume ratio of the base material 1a to the metal particles 1b was changed in various ways to manufacture single-layer hybrid bonded grinding wheels 20. As shown in FIG. 3, each single-layer hybrid bonded grinding wheel 20 includes a substrate 3, a bond layer 7, and a large number of abrasive grains 9. The bond layer 7 includes a first bond layer 7a provided on the substrate 3, and a second bond layer 7b provided on the first bond layer 7a. Each abrasive grain 9 is fixed in a single layer on the substrate 3 by the bond layer 7 with its surface exposed.

First, in the first step, a composition having a glassy composition shown in Table 1, numerous metal particles 1b (Ni particles, average particle size: 180 nm), numerous abrasive grains 9 (diamond, average particle size: 12 μm), binder resin (acrylic resin), and solvent (alcohol) were prepared.

The composition and metal particles 1a were placed in a ball mill so that the volume ratio of the composition to the base material was as shown in Table 2, and the ball mill was rotated. At this time, the surface density of the abrasive grains 9 was set to 20%. The surface density of the abrasive grains 9 was adjusted by adjusting the proportion of the abrasive grains 9 in the composition. For the obtained single-layer hybrid bonded grinding wheel 20, the abrasive grains 9 and the surface of the bond layer 7 were binarized from the SEM image, and the surface density of the abrasive grains 9 was calculated from the area occupied by the abrasive grains 9. In this way, the slurries of test samples 1 to 9 were obtained.

In the second step, as shown in FIG. 1, each slurry was applied to a predetermined thickness on an iron substrate 3. At this time, the thickness of each slurry was adjusted so that the first bond layer 7a was 10 to 50% of the diameter of the abrasive grains 9. The solvent in each slurry was evaporated to obtain a substrate compact consisting of the substrate 3 and a compact.

In the third step, the substrate molded body was fired at 750°C in a reducing atmosphere. In this way, an intermediate body 11 was obtained in which a first bond layer 7a was formed on the substrate 3. A micrograph of the surface of the intermediate body 11 using the slurry of test piece 4 is shown in Figure 2. As shown in Figures 1 and 2, the first bond layer 7a of the intermediate body 11 is composed of a glassy base material 1a formed by melting and solidifying the composition, and metal particles 1b dispersed in the base material 1a. In the intermediate body 11, the abrasive grains 9 are fixed in a single layer on the substrate 3 by the first bond layer 7a.

In the fourth step, the intermediate 11 was acid-washed with an aqueous solution of sulfuric acid or the like. After this, an electrolytic plating apparatus was prepared having a plating solution made of a sulfamic acid bath containing nickel sulfamate, nickel chloride, and boric acid, an anode, and a power source, and the intermediate 11 was connected to the cathode in the plating solution of the electrolytic plating apparatus and a voltage was applied. In this way, as shown in FIG. 3, a metallic second bond layer 7b was formed on the first bond layer 7a by electrolytic plating. At this time, the thickness of the second bond layer 7b was set so that the protruding amount of the abrasive grains 9 was 10 to 40% of the diameter of the abrasive grains 9. In this way, each single-layer hybrid bond grinding wheel 20 was obtained.

Figure 4 shows a micrograph of the surface of the single-layer hybrid bonded grinding wheel 20 of test piece 4. As shown in Figures 3 and 4, the first bond layer 7a of this single-layer hybrid bonded grinding wheel 20 has a glassy base material 1a and metal particles 1b dispersed in the base material 1a. The first bond layer 7a is dense and substantially free of pores. The second bond layer 7b is metallic.

However, when the slurry of test sample 1 was used, the first bond layer 7a peeled off from the substrate 3 while the second bond layer 7b was being formed in the fourth step. In addition, in the single-layer hybrid bond grinding wheel 20 using the slurry of test sample 8, the second bond layer 7b was only partially formed on the first bond layer 7a. When the slurry of test sample 9 was used, the second bond layer 7b could not be formed on the first bond layer 7a.

The resulting single-layer hybrid bonded grinding wheels 20 were used to prepare the grinding tool shown in FIG. 7. This grinding tool is made by bonding multiple single-layer hybrid bonded grinding wheels 20 to an annular base metal 15 with an adhesive. In one cutting tool, single-layer hybrid bonded grinding wheels 20 manufactured with the same slurry were bonded.

A wear test was then carried out under the following conditions to evaluate the life span.
Sliding type dry grinding test device Removal allowance: 5 μm (50 × 20 (mm) size)
Workpiece: Block of acrylic resin (PMMA) Surface roughness before processing: 0.90 μm

The service life was evaluated as follows: ◎ if grinding became impossible due to clogging when continuously grinding 50 or more workpieces, ◯ if grinding became impossible due to clogging when continuously grinding 25 to 50 workpieces, and × if grinding became impossible due to clogging when continuously grinding less than 25 workpieces. The results are also shown in Table 2.

From Table 2, it can be seen that the volume ratio of the base material 7a to the metal particles 1 in the first bond layer is preferably 5:95 to 90:10, and more preferably 10:90 to 80:20. If the volume ratio of the base material 7a to the metal particles 1 is less than 5:95, it is difficult to obtain a single-layer hybrid bonded grinding wheel. This is because the amount of glass in the first bond layer 7 is small, making it difficult to fix the metal particles 1 in the first bond layer 7 and difficult to hold the abrasive grains 3 to the base material 5. Also, even if the volume ratio of the base material 7a to the metal particles 1 is greater than 90:10, it is difficult to obtain a single-layer hybrid bonded grinding wheel. This is because the amount of metal particles 1 in the first bond layer 7 is small, making it easy for the bond strength between the first bond layer 7 and the second bond layer 11 to be insufficient.

(Test 2)
As in Test 1, in the first step, a composition, metal particles 1, abrasive grains 3, a binder resin, and a solvent were prepared. Then, these were put into a ball mill so that the volume ratio of the composition (based on the base material) to the metal particles 1 was 5:5, and the ball mill was rotated. At this time, as shown in Table 3, the surface density of the abrasive grains 9 was changed from 0.1 to 60%. In this way, the slurries of Examples 1 to 9 were obtained.

Steps 2 to 4 were carried out in the same manner as in Test 1 to obtain the single-layer hybrid bonded grindstones of Examples 1 to 9. A micrograph of the surface of the single-layer hybrid bonded grindstone of Example 3 is shown in Figure 5. Meanwhile, a commercially available single-layer metal bonded grindstone was prepared as a comparative example. The single-layer metal bonded grindstone of the comparative example has abrasive grains 3 similar to those of Examples 1 to 9 provided on a substrate 5 by electrochemical deposition. A micrograph of the surface of the single-layer metal bonded grindstone of the comparative example is shown in Figure 6. As shown in Figures 5 and 6, it can be seen that the single-layer hybrid bonded grindstone of Example 3 has a significantly lower surface density of abrasive grains than the single-layer metal bonded grindstone of the comparative example.

Grinding tools similar to those in Test 1 were prepared using the single-layer hybrid bonded grinding wheels of Examples 1 to 9 and the single-layer metal bonded grinding wheel of Comparative Example 1. Then, a wear test similar to that in Test 1 was conducted to evaluate clogging, life, and machined surface roughness. The life evaluation was the same as in Test 1.

Clogging was evaluated as follows: ◎ if there was no adhesion after grinding was completed, 〇 if it could be removed with air etc. after grinding was completed, and × if adhesion occurred and could not be removed even by blowing air etc. The results are also shown in Table 3.

The machined surface roughness was evaluated as follows: ◎ if the machined surface Ra of the workpiece was 0.2 μm or less, ◯ if it was more than 0.2 μm and 0.3 μm or less, △ if it was more than 0.3 μm and 0.4 μm or less, and × if it was more than 0.4 μm. These results are also shown in Table 3.

From Table 3, it can be seen that in the single-layer hybrid bonded grinding wheels 20 of Examples 1 to 9, the abrasive grains 9 are less likely to fall off during grinding. This is because the second bond layer 7b on the first bond layer 7a of these single-layer hybrid bonded grinding wheels 20 is metallic, which holds the abrasive grains 9 with high toughness. In particular, the single-layer hybrid bonded grinding wheels 20 of Examples 3 to 6 are preferred.

In addition, in the single-layer hybrid bonded grinding wheels 20 of Examples 1 to 9, since the base material 1a of the first bond layer 7a is vitreous, the ratio of abrasive grains in the composition that forms the vitreous can be adjusted as desired, and the surface density of the abrasive grains 9 on the substrate 3 can be reduced as desired. Therefore, in each single-layer hybrid bonded grinding wheel 20, the surface density of the abrasive grains 9 on the polishing surface can be reduced compared to conventional methods, so that even when used continuously over a long period of time, clogging and welding are unlikely to occur on the polishing surface, and the grinding resistance is unlikely to increase. According to the inventors' test results, if the surface density of the abrasive grains 9 is 50% or less, as in the single-layer hybrid bonded grinding wheels 20 of Examples 1 to 8, clogging is unlikely to occur on the polishing surface during grinding.

Furthermore, in the single-layer hybrid bonded grinding wheels 20 of Examples 1 to 9, the metallic second bond layer 7b and the metal particles 1b in the first bond layer 7a are both metallic, so they are strongly bonded, and the second bond layer 7b is strongly bonded to the first bond layer 7a. In particular, in the single-layer hybrid bonded grinding wheels 20 of Examples 1 to 9, since the metallic particles 1b and the second bond layer 7b are both Ni, this effect is presumably more pronounced.

Therefore, it can be seen that the single-layer hybrid bonded grinding wheels 20 of Examples 1 to 9 can achieve high durability and high polishing efficiency. It can also be seen that the single-layer hybrid bonded grinding wheels of the present invention can be manufactured by the manufacturing methods of Examples 1 to 9. In particular, by employing a conductive substrate 3 and employing an electrolytic plating method in the fourth step, the second bond layer 7b can be easily formed.

Although the present invention has been described above with reference to Tests 1 and 2 and Examples 1 to 9, it goes without saying that the present invention is not limited to the above Tests 1 and 2 and Examples 1 to 9, and can be modified as appropriate without departing from the spirit of the present invention.

For example, in the above Examples 1 to 9, the base metal 15, etc. and the substrate 3 were different, and multiple single-layer hybrid bond grinding wheels 20 were bonded to the base metal 15, etc. to form a cutting tool, but it is also possible for the base metal 15, etc. itself to be the substrate 3.

In addition, in the cutting tools of Examples 1 to 9 above, the base metal 15 is annular, but as shown in FIG. 8, a rod-shaped base metal 17 may be used, and multiple single-layer hybrid bond grinding wheels 20 may be bonded to the peripheral surface of this base metal 17. Furthermore, as shown in FIG. 9, a plate-shaped base metal 19 may be used, and multiple single-layer hybrid bond grinding wheels 20 may be bonded to one surface of this base metal 19.

The present invention can be used for grinding tools, etc.

Reference Signs List 3: Substrate 7: Bond layer 9: Abrasive grains 7a: First bond layer 7b: Second bond layer 1a: Base material 1b: Metal particles 11: Intermediate 20: Single-layer hybrid bond grinding wheel

Claims (4)

A first step of preparing a mixture containing a composition for forming a vitreous base material , a number of metal particles, and a number of abrasive grains , the volume ratio of the base material to the metal particles being 5:95 to 90:10 ;
A second step of providing the mixture on a substrate to form a substrate molded body;
a third step of firing the base material compact to form a first bond layer on the base material, the first bond layer including the base material and the metal particles dispersed in the base material, to form an intermediate body in which the abrasive grains are fixed to the base material in a single layer by the first bond layer;
and a fourth step of forming a metallic second bond layer on the first bond layer by an electrodeposition method, the second bond layer bonding with the metal particles, and obtaining a single-layer hybrid bonded grinding wheel having a surface density of the abrasive grains of 50% or less . The substrate is electrically conductive,
2. The method for producing a single-layer hybrid bonded grinding wheel according to claim 1 , wherein the fourth step is carried out by electrolytic plating . 3. The method for producing a single-layer hybrid bonded grinding wheel according to claim 1, wherein the metal particles and the metallic substance are made of the same kind of metal. the abrasive grains are diamond;
The metal particles are Ni,
The method for producing a single-layer hybrid bonded grinding wheel according to claim 3, wherein the metallic material includes Ni.

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