WO2005097409A1

WO2005097409A1 - Porous vitrified grinding wheel and method for production thereof

Info

Publication number: WO2005097409A1
Application number: PCT/JP2005/006595
Authority: WO
Inventors: Kazuyuki Ishioka; Takenori Kanda
Original assignee: Kure-Norton Co., Ltd.
Priority date: 2004-04-06
Filing date: 2005-04-04
Publication date: 2005-10-20
Also published as: JPWO2005097409A1; CN1938129A; CN1938129B; JP4769186B2; TW200538237A

Abstract

A porous vitrified wheel having a structure composed of abrasive grains, a binder and pores, characterized in that it comprises a binder comprising an inorganic adhesive and a glass frit, and natural pores and pores formed by a pore-forming agent; and a method for producing the porous vitrified wheel. The porous vitrified wheel is produced by the use of an inorganic adhesive and a blowing agent for forming pores and has a uniform wheel structure, exhibits good cutting quality and satisfactory durability and strength, even when it is a fine wheel such as the one having a porosity of 60 vol % or more and/or having a particle diameter of an abrasive grain of less than 100 μm.

Description

Specification

Porous vitrified grinding wheel and method for producing the same

Technical field

The present invention relates to a porous vitrified grinding wheel and a method for producing the same.

Background art

[0002] The main types of grinding and polishing whetstones include, by binder, vitrified whetstones, resinoid whetstones, metal whetstones, and electrodeposition whetstones. Among them, vitrified whetstones are widely used because of their sharpness, high durability and good dressability.

[0003] In general, a vitrified grindstone selects one or more kinds of inorganic powders such as clay, feldspar, and glass frit as raw materials of an abrasive and a vitrified binder, mixes the powder with a primary binder, and molds the mixture into a mold. Fill and mold. After the drying process, it is manufactured by firing at a high temperature of 600-1300 ° C.

[0004] On the other hand, a technique for manufacturing a grindstone using an inorganic adhesive that cures at a temperature lower than the firing temperature described above is disclosed (Patent Document 1). Specifically, paragraph "0005" states that the abrasive layer can be formed by directly baking the abrasive grain layer on a grindstone base at a low sintering temperature of about 150 to 300 ° C.

[0005] Also disclosed is a technique in which 50 to 30 parts by weight of boron carbide and 50 to 10 parts by weight of a ceramic material are added and mixed with 1 to 10 parts by weight of an aqueous solution of water glass, and then dried and fired at 800 to 1200 ° C. (Patent Document 2).

Patent Document 1: JP 2001-71268 A

Patent Document 2: JP-A-52-26094

Disclosure of the invention

Problems to be solved by the invention

[0006] As described in JP-A-2001-71268, a grindstone sintered at a low temperature using an inorganic adhesive is compared with a vitrified grindstone having a bending strength manufactured by a general method. Since it is low, the holding power of the abrasive grains is insufficient, and there is a problem in the life of the grinding wheel. In addition, in the production method described in Japanese Patent Application Laid-Open No. 52-26094, the amount of the added inorganic substance is small. Is not considered to be the main vitrisulfide binder that works in high-temperature sintering, so it cannot be expected to have sufficient strength.

[0007] The production of the above-mentioned inorganic grindstone has been studied from various aspects. However, in order to bring out the required grindstone characteristics, it is necessary to consider the use of inorganic binder and the like and the production conditions. Much remains to be done.

[0008] In particular, when manufacturing a porous vitrified grindstone, it is necessary to consider the uniformity of the grindstone structure and the strength of the grindstone in consideration of sharpness and high durability. If an organic pore-forming agent is used in the conventional vitrified eye manufacturing process, there is a problem in that shape retention is not maintained during firing, and firing shrinkage is large. Therefore, whetstones with high porosity, especially 60% by volume porosity The production of the above grindstones is limited. It is also conceivable to manufacture a porous grindstone using an inorganic hollow body, but since the film wall of the inorganic hollow body remains in the grindstone after firing, this action increases the grinding resistance during grinding. problems force ^s that.

[0009] On the other hand, in the production of conventional vitrified grinding wheels, there is also a problem that it is difficult to make the grinding wheel structure uniform. In particular, pores are likely to be non-uniform in a fine grinding stone having an abrasive grain diameter of less than 100 μm.

[0010] In view of the above problems, the present invention relates to a porous vitrified whetstone produced by using an inorganic adhesive and a foamable pore-forming agent, particularly a porosity of 60% by volume or more and / or abrasive grains. An object of the present invention is to provide a grindstone having a uniform grindstone structure, good sharpness, sufficient durability and strength, and a method for producing the same, even with a fine grindstone having a diameter of less than 100 μm.

Means for solving the problem

[0011] The porous and inorganic vitrified whetstone of the present invention that solves the above problems is a whetstone having a structure composed of abrasive grains, a binder, and pores, and is a bond formed by an inorganic adhesive and a glass frit. And natural pores and pores formed by a pore-forming agent.

[0012] In the porous vitrified whetstone of the present invention, the glass frit has a softening point of 300 to 900 ° C, preferably 400 to 900 ° C. [0013] Further, the grindstone of the present invention includes fused alumina-based abrasive grains, sol-gel alumina-based abrasive grains, silicon carbide-based abrasive grains, alumina zirconium-based abrasive grains, cerium oxide-based abrasive grains, silica-based abrasive grains, and CBN-based abrasive grains. It is preferable to have one or more abrasive grains selected from the group consisting of grains and diamond-based abrasive grains.

[0014] In the method for producing a porous vitrified grinding wheel according to the present invention, a liquid mixture obtained by dissolving an abrasive, an inorganic adhesive, a glass frit, and a pore-forming agent in water is poured into a mold, and the mixture in the mold is washed. It is characterized by drying and solidifying at room temperature to 300 ° C. and foaming the pore-forming agent at the same time, and baking the dried and solidified mixture at 600 to 1000 ° C. to obtain a vitrified whetstone.

[0015] In the production method of the present invention, as the pore-forming agent, a liquid foamable pore-forming agent may be used, or a solid foamable pore-forming agent may be used. Further, it is preferable to use a glass frit having a softening point of 300 to 900 ° C, preferably 400 to 900 ° C. The abrasive grains used are fused alumina-based abrasive grains, sol-gel alumina-based abrasive grains, silicon carbide-based abrasive grains, alumina zirconia-based abrasive grains, cerium oxide-based abrasive grains, silica-based abrasive grains, and CBN-based abrasive grains. One or more types can be selected from the group consisting of grains and diamond-based abrasive grains.

The invention's effect

The present invention can provide a porous vitrified grindstone having a binder formed of an inorganic adhesive and a glass frit and having substantially uniform pores formed of natural pores and a pore-forming agent. A fine grinding stone with a ratio of 60% by volume or more and / or a grain diameter of less than 100 μm, having a uniform grinding stone structure, excellent sharpness, high durability and strength, and a method for producing the same. can do.

Brief Description of Drawings

FIG. 1 is an electron micrograph of the grindstone structure of the test grindstone prepared in Example 1.

FIG. 2 is a cross-sectional view illustrating a schematic configuration of cup-type grindstones of Examples 3 and 4.

FIG. 3 is a photograph of a cup-shaped grindstone produced as Examples 3 and 4 taken from the front.

FIG. 4 is an enlarged photograph of the vicinity of a grinding wheel piece of the cup-type grinding wheel of FIG. 3 taken from the side.

Brief description of the sign

[0018] 1 Whetstone pieces

2 cup-shaped metal base 3 Grinding stone polishing surface

BEST MODE FOR CARRYING OUT THE INVENTION

The grindstone of the present invention is a porous vitrified grindstone manufactured by casting a mixture containing an abrasive, an inorganic adhesive, a glass frit, and a pore-forming agent.

[0020] The "porous vitrified grinding wheel" referred to in the specification of the present application does not include an organic primary binder, uses an inorganic adhesive as a substantial primary binder, and further uses a glass frit together with the inorganic adhesive. It means a grindstone that is sintered using and contains pores formed by a foaming agent and natural pores. According to the present invention, good pore formation is performed at the time of drying and solidifying the grindstone raw material mixture, and then vitrification proceeds through a glass frit, so that the grindstone has a uniform grindstone structure, particularly a fine and uniform pore structure, and A porous vitrified whetstone having sufficient strength can be manufactured.

First, each material used for manufacturing the grindstone of the present invention will be described.

[0022] The inorganic adhesive is an inorganic substance which cures at a relatively low temperature and mainly serves to maintain the shape of a grinding wheel from molding to firing. Such an inorganic adhesive is mainly composed of one or more of silica, alumina, alumina, silica, zirconia 'silica, zirconia, sodium silicate, aluminum phosphate, magnesium phosphate, and the like. , A binder such as silica sol, aluminum phosphate, magnesium phosphate and the like, and a binder using silicate ion and the like as a curing agent. In the case of using alkali silicate, for example, water glass as a binder, silicate ions are polymerized and cured by heating and dehydration. Preferred inorganic adhesives are those using sodium silicate as a main component and alkali silicate as a binder.

As the pore-forming agent, any of an organic pore-forming agent and an inorganic pore-forming agent such as an inorganic hollow body may be used, or they may be used together. In particular, a foamed pore-forming agent is preferred, and for example, spherical styrene foam is preferably used. As the foamable pore-forming agent used in the present invention, either a solid foaming agent or a liquid foaming agent may be used, or both may be used in an appropriate ratio. Preferably, a liquid foaming agent is used.

[0024] A preferred liquid foaming agent is a dialkyl group represented by the general formula ROOC-N = N-COOR (wherein each R represents a lower alkyl group of 1 to 4 which may be linear or branched). Zodicarboxylate. A more preferred dialkylazodicarboxylate is diisopropylpropylazodicarboxylate. Further, other dialkyl azodicarboxylates that can be used in the present invention include dimethyl azodicarboxylate, getyl azodicanoleboxylate, dipropyl azodicarboxylate, ditert-butyl azodicarboxylate. And mixtures thereof. These dialkylazodicarboxylates are thermally decomposed by heating to foam and form many foamed pores in the grindstone structure. Typically, its pyrolysis temperature is around 250 ° C and at room temperature it is non-volatile and safe. The bubbling starts at around 50 ° C. To obtain favorable pores, it is better to heat to 60-200 ° C. A liquid foaming agent represented by the above-mentioned dialkylazodicarboxylate foams at room temperature in an acidic solution, an alkaline solution, or when a phenol resin, a sulfonic acid, a butyl chloride, and a metal salt of a fatty acid are added. Occur. Since the inorganic adhesive solution used in the present invention is an alkaline solution, foaming occurs even at room temperature, and the water content of the cast product evaporates due to the heat at that time, and the cast product is solidified.

[0025] As described above, in the present invention, the foaming of the liquid foaming agent and the solidification of the inorganic adhesive can be started at room temperature without performing heating or cooling treatment. As used herein, the term room temperature refers to an ambient temperature at which foaming of the liquid foaming agent and solidification of the inorganic adhesive can proceed without heating or cooling the grindstone raw material. Can be defined as 0-30 ° C.

[0026] As described above, in the present invention, the use of an inorganic adhesive, which is an alkaline solution, is preferable since pore formation and grinding stone solidification due to foaming at room temperature occur.

[0027] Glass frit is an inorganic binder necessary for vitrifying a grindstone structure and sintering the grindstone. Typically, a glass frit whose chemical component is mainly borosilicate glass is used. it can. In addition, soda coal glass, various types of crystallized glass, and the like may be used, but are not limited thereto.

[0028] The ratio between the glass frit and the solid content of the inorganic adhesive can be changed as appropriate within the range of 3: 1 to 1: 7, but preferably 2.5: 1 to 1: 6. The softening point of the glass frit is preferably such that the temperature at which the glass frit starts melting at a temperature lower than the predetermined firing temperature is preferably 100 ° C higher than the firing temperature so that the glass frit is sufficiently softened and melted during firing. It is preferable that C is lower. However, firing temperature If the temperature difference between the temperature and the softening point is too large, problems such as cracks will occur during the manufacture of the grinding wheel. Therefore, the temperature difference is desirably 300 ° C or less.

[0029] The abrasive grains include fused alumina-based abrasive grains, sol-gel alumina-based abrasive grains, silicon carbide-based abrasive grains, alumina-zirconia-based abrasive grains, cerium oxide-based abrasive grains, silica-based abrasive grains, and CBN or Super-abrasive grains such as diamond-based abrasive grains can be suitably used. One or more types of abrasive grains to be used are selected from those described above according to the grinding conditions.

[0030] The abrasive particle size can be from F4 (according to the particle size indicated in "Type of coarse particles" described in "JIS R6001 Grain size of abrasive for grinding wheel") to an average particle size of 0.1 µm Can be used. Preferably, F4 (according to the particle size indication shown in “Type of coarse particles” described in “JIS R6001 Abrasive material for grinding wheel”) to average particle size of 0.2 μm it can. It is particularly preferable to use # 1000 (the particle size is described in `` JIS R6001 Grain size of abrasive for grinding wheel '') and is indicated by `` Electric resistance test method '' in `` Types of fine powder for precision polishing '' According to the given particle size display, the particle size distribution at the cumulative height of 50% point can be used at the average particle size of 0.5 / im.

Next, a method for manufacturing a grindstone of the present invention will be described.

[0032] In the manufacturing process of the grinding wheel of the present invention, the above-mentioned grinding wheel raw material is mixed and dispersed in an aqueous solution, and this is poured into a grinding wheel molding die. The poured liquid mixture is cooled to room temperature (0 to 30 ° C). It includes a step of drying and solidifying at ~ 300 ° C and foaming, and a step of firing the dried and solidified product at a temperature not lower than the melting temperature of the glass frit, specifically, at 600 to 1000 ° C. In this method, the casting method is aimed at increasing the dispersibility of each raw material to be mixed and forming a good and uniform grindstone structure.

[0033] In the production method of the present invention using the above-mentioned raw materials, in the drying and solidification step, the inorganic adhesive hardens at room temperature to 300 ° C after pouring, and at the same time, the foamable pore-forming agent foams. Artificial pores are formed. The merit of this is that it prevents defects in the production of cast wheels. In other words, at the time of curing, the moisture contained in the mixture evaporates and the molded product dries. At the time of this drying, cracks are generated on the molded product. According to the production method of the present invention, as the solidification proceeds, pores are formed in the liquid mixture by the foaming action of the pore-forming agent, so that the voids in the liquid mixture to escape to the outside are removed. A sinus will be formed. In this way, the pore-forming agent forms uniform pores in the liquid mixture and also functions to prevent cracking during production. This effect is particularly advantageous in a method using a liquid foaming agent having a higher dispersibility than a solid foaming agent.

[0034] Inside the grindstone manufactured by casting according to the present invention, natural pores originating from a portion thought to be traces of water and bubbles mixed in when preparing a liquid raw material, and a blowing agent added with The resulting artificial pores are formed, and the pores formed by the foaming agent are larger than the natural pores. Since both of these pores can be uniformly dispersed inside the grindstone, the produced grindstone can have a uniform grindstone structure with high porosity.

[0035] In addition, by performing the drying and solidifying treatment at a low temperature first as described above, there is also an effect of preventing cracks or deformation of a burnt stone product which may occur during subsequent high-temperature firing. In addition, since the raw material does not contain an organic primary binder, an unpleasant odor during firing and cracks due to the primary binder are prevented, and since the water in the grinding wheel is completely dried, the residual water content is reduced. The trouble during firing due to the above is also prevented.

[0036] Following the solidification step, the mixed molded product is fired at 600 to 1000 ° C. Here, the glass frit causes a chemical reaction with the inorganic adhesive to improve the strength. That is, according to the grinding wheel manufacturing method using a glass frit according to the present invention, after the inorganic adhesive is cured, the glass frit is further baked at 600 to 1000 ° C. to soften and melt the glass frit. As a result, the binding force between the compound and the compound is improved, and a chemical reaction occurs with the inorganic adhesive, whereby vitrification can be performed. On the other hand, the vitrified grinding wheel manufactured by the conventional method using only the inorganic adhesive has a lower bending strength as compared with the present invention, so the abrasive holding power is insufficient, and the life of the grinding wheel is shortened. .

[0037] As described above, in the present method, the steps of drying and solidification (curing) and baking are sequentially performed so that the properties of the inorganic adhesive, the glass frit, and the cell forming agent are sufficiently activated. This enables the production of desirable porous vitrified grinding wheels.

[0038] With regard to the composition of the grindstone, the production can be carried out with an abrasive grain ratio of 5 to 50% by volume and a porosity of 30 to 90% by volume. In particular, according to the present invention, a vitrified grindstone having a porosity of 60 to 90% by volume, which is generally difficult to produce, can be easily produced. The binder ratio, that is, the volume ratio of inorganic adhesive + glass frit, is the value obtained by subtracting the abrasive grain ratio and porosity from 100%. It is.

[0039] The present invention can provide a porous vitrified whetstone having characteristics of low grinding resistance and good finished surface roughness. The grindstone of the present invention can be favorably used in general grinding conditions, cylindrical grinding, flat grinding, internal grinding, die shaping and the like. In particular, the grindstone of the present invention can be favorably used for polishing IJ 'polishing using an iron-based material as a work material, and furthermore, a non-ferrous-based material such as silicon wafer, carbide, alumina, sapphire, quartz, carbide material, and nitrided material. It can be used well for grinding and polishing hard and brittle materials such as material materials, various glasses, and ceramic materials.

Hereinafter, examples of the present invention will be described together with comparative examples, but these exemplify the feasibility and usefulness of the present invention, and do not intend to limit the configuration of the present invention in any way. Example

[0041] [Bending strength test]

The bending strength of the grindstone to which the present invention was applied (Example 1) and the grindstone using only an inorganic adhesive as a binder (Comparative Example 1) were compared.

[0042] Tables 1 and 2 show the raw materials and mixing ratios of each test wheel.

[Table 1] Raw material mixing ratio of Example 1

Abrasive grains; WA # 15 ϋ 0 37.3 wt% Inorganic adhesive; F J — 5 2 130.1 t%

(Manufactured by Tokiwa Electric Co., Ltd.)

Glass frit (softening point 650 ° C) 2.9 t%

(Chemical _{composition: S i 0 2 3 7 wt} %

A "O 8 w t%

C a O 3 w t%

N a ₂ 0 1 4 wt%

B, 0 _{; t} 38 wt%)

Blowing agent: Gisoprot 2.3 wt%

Solvent; water 27.4 wt%

[Table 2] Material ratio of Example 1

Abrasive; W A # 15 5 0

Inorganic adhesive; F J— 5 2 1

(Manufactured by Tokiwa Electric Co., Ltd.)

Blowing agent; diisopropylazodicarboxyle

Solvent; water

(Example 1)

Preparation of Test Wheel of Example 1

1. The raw materials described above were uniformly mixed.

2. The slurry mixture was poured into a 120 × 30 mm mold.

3. Heated at 60 ° C for 72 hours.

4. The solid obtained by heating was removed from the mold.

7. Baking at 900 ° C for 7 hours.

8. After firing, the thickness direction was shaved to produce a 120 x 30 x 40 mm rectangular parallelepiped grinding wheel (Comparative Example 1)

Preparation procedure of the test wheel of Comparative Example 1:

1. The raw materials described above were uniformly mixed.

2. Pour the slurry mixture into a 120 x 30 mm mold.

3. Heated at 60 ° C for 72 hours.

4. After heating, the thickness direction was shaved to produce a 120 x 30 x 40 mm rectangular parallelepiped square whetstone

Transliteration,

In accordance with the JIS standard (Bending strength test method for fine ceramics R1601, 2004), each test whetstone was subjected to a three-point bending strength at a span distance of 100 mm and a load drop speed of 1. Omm / min. Three test wheels were manufactured, and the average value of the three test wheels was used as comparison data.

Table 3 shows the results of the bending strength test.

[Table 3] Strength value (MPa)

Example 1 3 0

Comparative Example 1 1 0

[0048] As shown in Table 3, the test grindstone of Example 1 had three times the bending strength of that of Comparative Example 1. This is the effect of adding the glass frit according to the present invention and firing at a high temperature of 900 ° C.

FIG. 1 is an electron micrograph of the test grindstone prepared in Example 1. Looking at the microstructure, it can be seen that pores having a uniform pore diameter are formed by the liquid foaming agent together with fine natural pores.

[0050] [Grinding test 1]

A grinding test was performed using a test grindstone (Example 2) to which the present invention was applied, and the finished surface roughness (Ra, Rz) was measured.

(Example 2)

Preparation of Test Stone Stone of Example 2

1. The same ingredients as described in Example 1 were uniformly mixed.

2. The slurry mixture was poured into a mold having an outer diameter of 205 mm and a hole diameter of 50 mm.

3. Heated at 60 ° C for 72 hours.

4. The solid obtained by heating was removed from the mold.

7. Baking at 900 ° C for 7 hours.

8. After sintering, finishing was performed to produce 1810 whetstone 205 10 1150111111.

Table 4 shows grinding test conditions.

[Table 4] Grinding test conditions

Whetstone dimensions 25 O X t l O X h 5 O. 8 1 Λ Whetstone

Work material Material S 5 5 C (Hardened material 58 HRC)

Dimension 100 mm (length) X 5 mm (Ψ 畐)

Grinding fluid Name Crecut N S 2 0 1

Concentration 2%

Flow 15 liters Z min

Grinding machine type Horizontal surface grinding machine manufactured by Okaki Machine Works

Model CNC-5 2 B (7.5 kw)

Dressing conditions Dresser: Nip dresser

Wheel speed: 33 mZ s

Dress lead: 0.0 5 mm / r e v

Dress notch: 0.0 0 1 mm no a s s

Grinding method Surface traverse grinding

Wheel peripheral speed: 3 3 mZ s

Table speed: 1 6 7 m / s

Cross feed: 2 mm / a s s (round trip)

Grinding depth: 0.00 l mm / p a s s

Allowance: 0.2mm

Spark-out: l p a s s 什 h f fl. Sa (Ra Rz) Calculation procedure:

[Ra]

The center line average roughness (Ra) is obtained by extracting a portion of measurement length 1 from the roughness curve in the direction of the center line, the X-axis is the center line of this extracted portion, the Y-axis is the vertical magnification direction, and the roughness is Curve y = f) means the value calculated by the following formula in micrometer (μΐη)

[0054] [Number 1]

[0055] [Rz] The surface roughness of the finished surface of the grindstone to be tested is measured as the ten-point average roughness Rz. The ten-point average roughness Rz is extracted from the roughness curve by the reference length in the direction of the average line, measured in the vertical magnification direction from the average line of the extracted part, and the elevation of the highest peak to the fifth peak is measured. It is calculated as the sum of the average of the absolute values of Υρ and the average of the absolute values of the elevations Υν from the lowest to the fifth valley bottom. In the present example, Rz was in the range of more than 0.50 xm and 10.0 zm or less, and the classification of the reference length of 0.8 mm and the evaluation length of 4 mm was followed.

¾ff shaving test

The finished surface roughness (Ra, Rz) of the test whetstone of this example was as follows.

[0056] Ra 0.014 xm

Rz 0.102 zm

As shown by the grinding test results, the test grindstone of this example had good surface roughness. This indicates that the grindstone manufactured according to the present invention can perform good grinding for the processing required according to the surface roughness of the work material.

[0057] [Grinding test 2]

Using a test grindstone to which the present invention was applied, a grinding test was performed using a silicon wafer as a work material, and the finished surface roughness, grinding power, whetstone consumption, and work material removal amount were evaluated.

[0058] Tables 5 and 6 show the raw materials and mixing ratios of the test grindstones of Examples 3 and 4.

[0059] Raw Material Mixing Ratio of Example 3

Abrasive; DIA # 3000 (3-6 m) 1 2 w t%

Inorganic adhesive; F J— 52 1 78 w t%

(Manufactured by Tokiwa Electric Co., Ltd.)

Glass frit (softening point 650 ° C) 69 w t%

(Chemical composition: S i Ο ₂ 37 wt%

A O 8 w t%

C a O 3 w t%

N a, 0 1 4 w t%

B, 0 _{; i} 38 wt%

Blowing agent; diisopropylpropylazodicarboxyle 41 wt%

Solvent; water 50 wt% [Table 6] Raw material mixing ratio of Example 4

Abrasive grains; DIA # 3 (J00 (3 to 6 im) 39.91 wt% Inorganic adhesive; FJ5 2 1 1 7.99 wt%

(Manufactured by Tokiwa Electric Co., Ltd.)

Glass frit (softening point 650.C) 9.05 wt% (Chemical composition: SiO 2 37 wt%)

A 1, Ο 8 w t%

C a O 3 w t%

N a 0 1 4 w t%

B ₂ 0 _{: J} 3 8 wt%

Blowing agent; disopropylazodicarbo 35 wt% solvent; water

2 1 t%

(Examples 3 and 4)

Preparation procedure of test wheels of Examples 3 and 4:

1. The raw materials described above were uniformly mixed to form a slurry.

2. The slurry mixture was poured into a 90 mm long, 70 mm wide mold.

3. Heated at 60 ° C for 24 hours.

4. The solid prepared above was removed from the mold.

5. Firing at 850 ° C for 7 hours in air atmosphere.

6. The composition of the grindstone after firing was the same as the grindstone of Example 3, with the abrasive grain volume ratio of 20.3%, the binder volume ratio of 18.9%, and the porosity of 60.8%. With the grindstone of Example 4, the volume ratio of abrasive grains was 18.6%, the volume ratio of binder was 11.3%, and the porosity was 70.1%.

7. In order to produce a cup-shaped grindstone having the shape shown in FIG. 2, 28 segment grindstone pieces each having a length of 20 mm, a width of 3 mm, and a height of 5 mm were produced in accordance with the above-mentioned production procedure. After hardening, each grinding wheel piece (1) was pasted at equal intervals on the ring-shaped peripheral part of the cup-shaped base (2), and finished to produce a cup-shaped grinding wheel of φ200 X t35 Xh40mm ( See photos in Figures 3 and 4).

[Table 7] Grinding test conditions:

Whetstone dimensions φ 2 0 0 X t 3 5 X h 4 Omm Cup type whetstone

Work material Material: Silicon wafer

Dimensions: 20 O mm (diameter) X O. 9 mm (thickness)

Grinding fluid Name: distilled water

: 1 2 liter Zm i n.

Grinding machine: Vertical surface grinding machine manufactured by Toshiba Machine Co., Ltd.

Model: UVG-380B

Dressing condition: Dresser: WA # 3 0 0 0

Wheel peripheral speed: 1 9 1 O min-1

Table rotation speed 50 m 1 n-1

Dress cut 20 μ / min X l Op a s s Spark ゥ at 30 s e c.

Grinding method: Grinding method: Wet in-feed grinding

Wheel peripheral speed: 1 9 1 Om i n-1

Table rotation speed: 5 Om i n- Grinding wheel depth: 20 i m / m i n

Allowance: 40 m

Sparkart: 10 sec.

Number of grinding: 10

The method of obtaining each evaluation item is as follows.

Calculate the height of the ffl Ra (u m):

The finish surface roughness Ra was determined by the same calculation procedure as in the above-described grinding test 1. Grinding power (kW):

The power consumption of the grinding wheel motor is W, and it can be obtained by the formula: 612XW / peripheral speed (60/100) In addition, the said peripheral speed of a grindstone was used as peripheral speed.

Whetstone wear (um):

It was determined using the automatic measurement function of the grinding dimensions of the grinder.

Workpiece removal (um):

test results:

[Table 8] Wafer grinding number Ra (nm) Grinding power (kw)

Example 3 Example 4 Example 3 Example 4

1 2 8 3 2 2.4 2.3

2 2 9 2 9 2.7 2.5

5 2 5 2 4 3.0 8.3

1 0 2 3 2 3 3.4 3.6 Table '9] wafer one grinding number grindstone consumption (mu m) wafers one removal amount (ji _m)

Example 3 Example 4 Example 3 Example 4

1 (). 4 0. 4 3 9 4 0

2 0.6 0.6 0.4 3 7 4 0

5 0.7 0.7 0.9 3 6 3 9

1 0 1.3 1.2 3 7 3 8

In both Example 3 and Example 4, the wafer removal amount showed a removal amount close to the target removal amount of 40 zm. With regard to grinding wheel wear, no abnormal wear or stagnation of wear amount was observed, indicating that wafer removal was performed normally and grinding work was performed smoothly. Abnormal values were not found in the characteristics of finished surface roughness (Ra) and grinding power (Ft). From the above results, it was shown that the grindstone of the example can perform proper and good grinding even in a grinding operation for a silicon wafer.

Claims

The scope of the claims

[1] A grindstone having a structure composed of abrasive grains, a binder, and pores, having a binder formed by an inorganic adhesive and a glass frit, and having pores formed by natural pores and a pore-forming agent. Vitrifide whetstone.

[2] The porous vitrified stone according to claim 1, wherein the glass frit has a softening point of 300 to 900 ° C.

[3] The porous vitrified whetstone according to claim 2, wherein the softening point of the glass frit is 400 to 900 ° C.

[4] The abrasive grains are fused alumina-based abrasive grains, sol-gel alumina-based abrasive grains, silicon carbide-based abrasive grains, alumina zirconia-based abrasive grains, cerium oxide-based abrasive grains, silica-based abrasive grains, CBN-based abrasive grains, And at least one selected from the group consisting of diamond-based abrasive grains,

3. The porous vitrified whetstone according to item 1 above.

[5] A liquid mixture obtained by dispersing an abrasive, an inorganic adhesive, a glass frit, and a pore-forming agent in water is poured into a mold, and the mixture in the mold is dried and solidified at room temperature to 300 ° C. A method for producing a porous vitrified grinding wheel, characterized in that the pore forming agent is foamed, dried and solidified, and further fired at 600 to 1000 ° C to obtain a vitrified grinding wheel.

[6] The production method according to claim 5, wherein a liquid foamable pore-forming agent is used as the pore-forming agent.

7. The production method according to claim 5, wherein a solid foamable pore-forming agent is used as the pore-forming agent.

[8] The glass frit having a softening point of 300 to 900 ° C. is used.

The manufacturing method according to any one of claims 1 to 7, wherein

[9] The production method according to claim 8, wherein a glass frit having a softening point of 400 to 900 ° C is used.

[10] The abrasive grains used are fused alumina-based abrasive grains, sol-gel alumina-based abrasive grains, silicon carbide-based abrasive grains, alumina zirconium-based abrasive grains, cerium oxide-based abrasive grains, silica-based abrasive grains, and CBN-based abrasive grains. The method according to any one of claims 5 to 9, wherein one or more kinds are selected from the group consisting of grains and diamond-based abrasive grains.