KR20070022028A - Porous vitrified grinding wheel and method for production thereof - Google Patents

Abstract

The present invention is a porous grinding wheel prepared using an inorganic adhesive and an effervescent pore forming agent, in particular having a grinding wheel structure even in fine grinding wheels such as porosity of 60% by volume or more and / or grinding wheel diameter of less than 100 µm, The present invention provides a whetstone having a good cutting feeling and sufficient durability and strength, and a method of manufacturing the same. The present invention is a whetstone having a structure consisting of whetstone particles, binders and pores, characterized in that it has a binder formed by an inorganic adhesive and a glass frit and pores formed by natural pores and pore formers. It is about.

Description

Porous vitrified grinding wheel and its manufacturing method {POROUS VITRIFIED GRINDING WHEEL AND METHOD FOR PRODUCTION THEREOF}

The present invention relates to a porous bituminous grindstone and a method for producing the same.

The main types of grinding and polishing grindstones listed by binders include vitrified grindstones, resinoid grindstones, metal grindstones and electrodeposited grindstones. Among them, non-refined grinding wheels are widely used because they have good cutting feeling, high durability, and good dressing property.

In general, non-refined grindstone is a raw material of a grinding stone and a non-refining binder, and at least one type of inorganic powder such as clay, feldspar, and glass frit is selected and mixed with the primary binder, and the mixture is filled into a mold to be molded. do. After the drying process, it is produced by firing at a high temperature of 600 ~ 1300 ℃.

On the other hand, the technique of manufacturing a grindstone using the inorganic adhesive hardened | cured at temperature lower than the said baking temperature is disclosed (patent document 1). Specifically, it is described in the paragraph that the grinding stone layer can be formed by directly welding the grinding stone at a low temperature around 150 to 300 ° C. in the sintering temperature.

Moreover, the technique which adds and mixes 1-10 weight part of water glass aqueous solutions with respect to 50-30 weight part of boron carbide, and 50-10 weight part of ceramic materials, and bakes at 800-1200 degreeC after drying is also disclosed (patent document 2). ).

[Patent Document 1]

Japanese Patent Application Laid-Open No. 2001-71268

[Patent Document 2]

Japanese Patent Application Laid-Open No. 52-26094

As described in Japanese Unexamined Patent Publication No. 2001-71268, grindstones sintered at low temperatures using an inorganic adhesive have a low grinding force due to their lack of retention of grindstone particles because their bending strength is lower than that of non-refined grindstones prepared by the conventional method. There is a problem. Moreover, since the amount of the inorganic substance added is small in the manufacturing method of Unexamined-Japanese-Patent No. 52-26094, since it is considered that it is not the main vitrified binder which acts at high temperature sintering, sufficient strength etc. cannot be expected.

Although the preparation of the above-mentioned inorganic whetstone has been examined in various aspects, there are many matters to be examined regarding the usage method and manufacturing conditions of the inorganic binder and the like in order to derive the required whetstone properties.

In particular, in the case of manufacturing a porous bituminous grindstone, the feeling of cutting is good, and in addition to the high durability, the uniformity of the grindstone structure and the strength of the grindstone must be considered. In the conventional vitrified manufacturing process, organic pore-forming agents do not maintain shape during firing and have a high plastic shrinkage rate. Therefore, grindstones having a high porosity, in particular, grindstones having a porosity of 60 vol% or more Manufacturing is limited. It is also conceivable to manufacture porous grindstones using pores in inorganic materials. However, since the membrane walls of the inorganic hollow bodies remain in the grindstones after firing, there is a problem that the grinding resistance during grinding increases due to this action.

On the other hand, in the manufacture of conventional non-refined grinding wheels, there is also a problem that the grinding wheel structure is difficult to uniformize. In particular, fine grinding wheels having a particle diameter of less than 100 µm tend to be non-uniform in pore dispersion.

In view of each of the above problems, the present invention is a porous bituminous grindstone prepared using an inorganic adhesive and a foamable pore-forming agent, in particular even in fine grindstones such as porosity of 60 vol% or more and / or grindstone particle diameter of less than 100 μm. An object of the present invention is to provide a whetstone having a uniform grindstone structure, good cutting feeling, and sufficient durability and strength, and a method of manufacturing the same.

The porous and inorganic non-fine grinding wheel of the present invention which solves the above problems is a grinding wheel having a structure consisting of whetstone particles, a binder and pores, and is formed by a binder formed by an inorganic adhesive and a glass frit, and natural pores and pore-forming agents. It is characterized by having the pores formed by.

The porous bituminous grindstone of the present invention has a softening point of 300 to 900 占 폚, preferably 400 to 900 占 폚 for the glass frit.

Further, the grinding wheel of the present invention includes molten alumina grinding wheel particles, sol-gel alumina grinding wheel particles, silicon carbide grinding wheel particles, alumina-zirconia grinding wheel particles, cerium oxide grinding wheel particles, silica grinding wheel particles, CBN grinding wheel particles and diamond type It is good to have a grindstone particle selected from the group which consists of grindstone particles.

In the method for producing a porous bituminous grindstone according to the present invention, a liquid mixture obtained by dissolving a grindstone material, an inorganic adhesive, a glass frit, and a pore former in water is poured into a mold, and the mixture in the mold is subjected to normal temperature to 300 ° C. Drying solidification at the same time and the pore-forming agent is foamed to dry the solidified mixture is further characterized in that it is calcined at 600 ~ 1000 ℃ to obtain a bit grinding grinding stone.

In the production method of the present invention, a liquid foamable pore-forming agent may be used as the pore-forming agent, or a solid foamable pore-forming agent may be used. Moreover, it is good to use the glass frit whose softening point is 300-900 degreeC, Preferably 400-900 degreeC. The grindstone particles used are molten alumina grindstone, sol-gel alumina grindstone, silicon carbide grindstone, alumina-zirconia grindstone, cerium oxide grindstone, silica grindstone, CBN grindstone and diamond grindstone. One or more types can be selected from the group which consists of particle | grains.

The present invention can provide a porous bituminous grindstone having a binder formed by an inorganic adhesive and a glass frit, and roughly uniform pores formed by natural pores and a pore-forming agent, in particular porosity of 60 vol% or more and / or whetstone Particles For fine grinding wheels having a particle diameter of less than 100 µm, a grinding wheel having a uniform grinding structure, good cutting feeling, high durability and strength, and a method of manufacturing the same can be provided.

1 is an electron micrograph of the whetstone structure of the test whetstone prepared in Example 1,

2 is a cross-sectional view showing a schematic configuration of a cup grinding wheel of Examples 3 and 4;

3 is a photograph taken from the front of the cup-shaped grindstone produced in Examples 3 and 4,

4 is an enlarged photograph taken from the side of a whetstone piece of the cup-shaped grindstone of FIG. 3.

※ Explanation of code for main part of drawing

1: Whetstone 2: Cup type metal price

3: grinding wheel polishing surface

The grindstone of the present invention is a porous bituminous grindstone manufactured by pouring a mixture comprising a grinding stone, an inorganic adhesive, a glass frit, and a pore forming agent.

As used herein, the term "porous bituminous grinding stone" does not contain an organic primary binder and is sintered using an inorganic adhesive as a substantially primary binder and using a glass frit together with an inorganic adhesive, It means a grindstone containing pores and natural pores formed by. According to the present invention, good pore formation is carried out at the time of dry solidification of the whetstone raw material mixture, and then, after vitrification through the glass frit, a uniform whetstone structure, in particular, a fine and uniform pore structure, and also sufficient strength Porous refined grinding wheel having can be prepared.

First, each material used for manufacture of the whetstone of this invention is demonstrated.

Inorganic adhesives are inorganic materials that cure at relatively low temperatures and are primarily helpful in maintaining whetstone shape from molding to firing. Such an inorganic adhesive includes water glass, silica sol, aluminum phosphate, phosphoric acid based on one or two or more of silica alumina, alumina, silica, zirconia, silica, zirconia, sodium silicate, aluminum phosphate and magnesium phosphate as main components. Since binders, such as magnesium, and silicate ions are used as a hardening | curing agent, it can select suitably. The alkali silicate system, for example, water glass as a binder is cured by polymerization of silicate ions by heating dehydration. Preferred inorganic adhesives are those in which alkali silicate is used as a binder, with sodium silicate as a main component.

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

Preferred liquid blowing agents are dialkyl azodicarboxylates represented by the general formula ROOC-N = N-COOR (wherein each R represents a 1-4 low-speed alkyl group which may be linear or branched). More preferable dialkyl azo dicarboxylate is diisopropyl azo dicarboxylate. In addition, other dialkyl azo dicarboxylates that can be used in the present invention include dimethyl azo dicarboxylate, diethyl azo dicarboxylate, dipropyl azo dicarboxylate, ditetra-butyl azo dicarboxylate and those Contains a mixture of. These dialkyl azodicarboxylates are thermally decomposed by heating to foam to form many foamed pores in the grindstone structure. Typically, the pyrolysis temperature is around 250 ° C., and there is no volatility at room temperature, so it is safe. The foaming starts around 50 ° C., but heating to 60-200 ° C. is preferred to obtain desirable pores. The liquid blowing agent typified by the dialkyl azodicarboxylate is foamed at room temperature under acidic solution, alkaline solution, or when phenol resin, sulfonic acid, vinyl chloride, and fatty acid metal salt are added. Since the inorganic adhesive solution used in the present invention is an alkaline solution, foaming occurs even at room temperature, and the moisture of the inflow molding product evaporates by the heat at that time to solidify the molding.

As mentioned above, in this invention, foaming of a liquid foaming agent and solidification of an inorganic adhesive agent can be started at normal temperature, without performing a heating or cooling process. As used herein, the term room temperature refers to an ambient temperature at which foaming of a liquid blowing agent and solidification of an inorganic adhesive may proceed without heating or cooling a raw material of a grindstone, specifically, 0 to 30 ° C. Can be.

As described above, in the present invention, the use of an inorganic adhesive which is an alkaline solution is preferable because pore formation and grinding of the grindstone due to foaming at room temperature occur.

The glass frit is an inorganic binder required to sinter the whetstone by vitrifying the whetstone structure, and typically, the chemical component thereof is mainly borosilicate glass. In addition, although soda coal glass, various crystallized glass, etc. may be used, it is not limited to these.

Although the ratio of glass frit and inorganic adhesive solid content can be suitably changed in the range of 3: 1-1: 7, 2.5: 1-1: 6 are preferable. The softening point of the glass frit is preferably a temperature at which melting starts at a temperature lower than the predetermined firing temperature so that the glass frit is sufficiently softened and melted at the time of firing, for example, it is preferably about 100 ° C lower than the firing temperature. However, if the temperature difference between the firing temperature and the softening point is too large, defects such as cracking occur during grinding, so the temperature difference is preferably 300 ° C or lower.

The grindstone particles include molten alumina grindstone particles, sol-gel alumina grindstone particles, silicon carbide grindstone particles, alumina-zirconia grindstone particles, cerium oxide grindstone particles, silica grindstone particles and CBN or diamond grindstone particles. Etc. can be used suitably. The grindstone to be used is selected from one or more of the above according to the grinding conditions.

The grindstone particle size can be used from F4 (according to the particle size indication shown in "Types of Assembly" described in "Risk Size of Abrasive Grain for JIS R6001") to an average particle diameter of 0.1 µm. Preferably, it can be used from F4 (according to the particle size indication shown in "Type of granulation" described in "Risk particle size of JIS R6001 grinding wheel abrasive") to an average particle diameter of 0.2 µm. Particularly suitably, it is a particle size indication described in # 1000 (the particle size of the abrasive for grinding grinding stone of JIS R6001), and the cumulative height is 50% according to the particle size indication according to the electrical resistance test method in the kind of fine grinding fine powder. , Particle size distribution of points 11.5 ± 1.0 µm) to an average particle diameter of 0.5 µm.

Next, the manufacturing method of the whetstone of this invention is demonstrated.

In the manufacturing process of the whetstone of the present invention, a step of mixing and dispersing the above-mentioned whetstone raw material in an aqueous solution and pouring it into a mold for grinding stone, drying and solidifying the poured liquid mixture at room temperature (0-30 ° C) to 300 ° C The process of foaming and the dried solidified substance are baked at the melting temperature or more of glass frit, specifically, 600-1000 degreeC. Inflow molding in this method has the purpose of forming a good uniform grindstone structure by increasing the dispersibility of each raw material to be mixed.

In the production method of the present invention using the above raw materials, the inorganic adhesive is cured at room temperature to 300 ° C after flowing in a dry solidification step, but at the same time, the foaming pore former is foamed to form artificial pores. As an advantage, there is a function of preventing the manufacturing defects of the grinding wheel to be introduced. That is, the moisture contained in the mixture at the time of hardening evaporates and the molded article dries, but there may be residual cracks on the molded article during this drying. According to the manufacturing method of the present invention, since the pores are formed by the foaming action of the pore-forming agent in the liquid mixture when the solidification proceeds, it forms a cavity for discharging the moisture in the liquid mixture to the outside. In this way, the pore-forming agent forms uniform pores in the liquid mixture and also functions to prevent the occurrence of residual cracks during manufacture. This effect is particularly advantageous in the method of using a liquid blowing agent which is more dispersible than a solid blowing agent.

In the grindstone produced by the inflow molding according to the present invention, the natural pores derived from the air bubbles and the parts considered to be traces of water missing when preparing the liquid raw material and artificial pores derived from the added blowing agent are formed. , The pores due to the blowing agent are larger pores than natural pores. Since pores of both can be uniformly dispersed in the grindstone, the grindstone produced can have a uniform grindstone structure having a high porosity.

In addition, as described above, by drying and drying at a low temperature, there is also an effect of preventing cracking or deformation of the whetstone calcined product which may be generated during subsequent high temperature firing. In addition, since the raw material does not contain an organic primary binder, abnormal odors during firing and cracks caused by the primary binder are prevented, and moisture in the grindstone is completely dried. Is also prevented.

Subsequent to the above solidification step, the mixed molding is fired at 600 to 1000 ° C. Here, the glass frit chemically reacts with the inorganic adhesive to improve the strength. In other words, according to the present invention, in the manufacture of whetstone using glass frit, since the glass frit is softened and melted after curing of the inorganic adhesive and then fired at 600 to 1000 ° C., the glass frit improves the binding force with the whetstone particles. Inorganic adhesives can also be chemically reacted and vitrified. On the other hand, the non-refined grindstone manufactured by the conventional method using only an inorganic adhesive has a low bending strength compared with the present invention, so that the grindstone holding force is insufficient and the grindstone life is shortened.

As described above, this method enables the production of a preferable porous bituminous grindstone by sequentially performing each step of dry solidification (curing) and firing so as to make full use of the characteristics of the inorganic adhesive, the glass frit and the bubble forming agent. It is.

As a grindstone composition, it can manufacture in the range of 5-50 volume% of grindstone particle sizes, and 30-90 volume% of porosities. In particular, according to the present invention, it is possible to easily produce a bituminous grinding stone having a porosity of 60 to 90% by volume, which is generally difficult to manufacture. In addition, the binder ratio, that is, the volume ratio of the inorganic adhesive + glass frit, is 100% minus the grindstone and porosity.

The present invention can provide a porous bituminous grindstone having characteristics of low grinding resistance and good finish surface roughness. The grindstone of the present invention can be favorably used in general grinding conditions, cylindrical grinding, planar grinding, internal grinding, gross grinding, and the like. In particular, the grinding wheel of the present invention can be used well for grinding and polishing using iron-based materials as workpieces, and also silicon wafers, cemented carbide, alumina, sapphire, quartz, carbide materials, nitride materials, various glass and ceramic materials, which are nonferrous materials. It can be used satisfactorily for grinding and polishing of hard brittle materials, such as these.

Hereinafter, although the Example of this invention is described with a comparative example, these illustrate the feasibility and usefulness of this invention, and there is no intention of limiting the structure of this invention at all.

(Example)

[Bending Strength Test]

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

Table 1 and Table 2 show the raw materials and the mixing ratio of each test whetstone.

Raw material mixing ratio of Example 1 Grindstone: WA # 1500 37.3 wt% Inorganic adhesive: FJ-521 30.1 wt% (Tokiwa Electric Co., Ltd.) Glass frit (softening point 650 ℃) 2.9 wt% (Chemical composition: SiO ₂ 37 wt% Al ₂ O 8 wt% CaO 3 wt% Na ₂ O 14 wt% B ₂ O ₃ 38 wt%) Foaming agent: Diisopropylazodicarboxylate 2.3 wt% Solvent: Water 27.4 wt%

Raw material mixing ratio of Comparative Example 1 Grindstone: WA # 1500 38.4 wt% Inorganic adhesive: FJ-521 31.0 wt% (Tokiwa Electric Co., Ltd.) Foaming agent: Diisopropylazodicarboxylate 2.3 wt% Solvent: Water 28.3 wt%

(Example 1)

Example  Production procedure of the test whetstone of 1;

1. The raw materials described above were uniformly mixed.

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

3. Heated at 60 ° C. for 72 hours.

4. The solid obtained by heating was taken out from the mold.

5. It baked at 900 degreeC for 7 hours.

6. After baking, the thickness direction was cut, and the square grindstone of 120x30x40 mm was produced.

(Comparative Example 1)

Production procedure of the test whetstone of Comparative Example 1;

1. The raw materials described above were uniformly mixed.

2. The slurry mixture is poured into a 120 x 30 mm mold.

3. Heated at 60 ° C. for 72 hours.

4. After heating, the direction of thickness was cut, and a square whetstone of 120 × 30 × 40 mm was produced.

Evaluation order;

According to the JIS standard (Test method for bending strength of fine ceramics R1601, 2004), each test grindstone was subjected to three-point bending strength at a span distance of 100 mm and a load drop speed of 1.0 mm / min. Three test grindstones were prepared for each of three average values as comparison data.

Table 3 shows the results of the bending strength test.

Strength value (MPa) Example 1 30 Comparative Example 1 10

As shown in Table 3, the test grindstone of Example 1 had a bending strength three times as compared with that of Comparative Example 1. According to the present invention, the glass frit is added and fired at a high temperature of 900 ° C.

1 is an electron micrograph of the test whetstone prepared in Example 1. FIG. Looking at the texture state, it can be seen that uniform pores of pore diameter are formed by the liquid blowing agent together with the fine natural pores.

[Grinding test 1]

The grinding test was performed using the test grindstone (Example 2) which applied this invention, and the finish surface roughness Ra and Rz were measured.

(Example 2)

Production procedure of the test whetstone of Example 2;

1. The same raw materials as described in Example 1 were mixed uniformly.

2. The slurry mixture was poured into a mold having a circumference 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 taken out from the mold.

5. It baked at 900 degreeC for 7 hours.

6. After firing, finishing was performed to prepare 1A whetstone of φ205 × t10 × h50 mm.

Table 4 shows the grinding test conditions.

Grinding test condition Grinding wheel size: Φ205 × t10 × h50.8 1A Grinding material Material: S55C (Welding material 58HRC) Dimension: 100 mm (Length) × 5 mm (Width) Grinding liquid Name: Cricut NS201 Concentration: 2% Flow rate: 15 liter / Min. Grinding Machine Type: Okaki Manufacturing Co., Ltd. Horizontal Shaft Grinding Machine Type: CNC-52B (7.5kw) Dressing Condition: Dresser: Nip Dresser Grinding Wheel Spinning Speed: 33 m / s Dress Lead: 0.05 mm / rev Dress Cutting: 0.001 mm / pass × 10 pass Grinding method: Plane traverse grinding wheel Main speed: 33 m / s Table speed: 167 m / s Cross feed: 2 mm / pass (round trip) Grinding cutting: 0.001 mm / pass Acquisition value: 0.02 mm Sparkout : 1 pass

Finish surface roughness (Ra, Rz) calculation order;

[Ra]

The center line average roughness Ra extracts a portion of the measurement length 1 from the curve of roughness in the direction of the center line, the center line of the pulled out portion is the X axis, the direction of the vertical magnification is the Y axis, and the roughness curve y = f ( When represented by x), what is calculated | required by the following formula means what was shown by the micrometer (micrometer).

[Rz]

The surface roughness at the finish surface of the grindstone to be tested is measured as a 10 point average roughness Rz. The 10-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 subtracted portion, and the elevation of the fifth peak from the highest calculated point (Yp). It is calculated as the sum of the average value of the absolute value of) and the average value of the absolute value of the elevation Yv of the bone floor from the lowest bone floor to the fifth. In the present Example, Rz was 0.50 micrometer or more and 10.0 micrometers or less, and it followed the division of the reference length 0.8 mm and the evaluation length 4 mm.

Grinding test results

Finish surface roughness (Ra, Rz) of the test whetstone of this Example was as follows.

Ra 0.014 μm

Rz 0.102 μm

As shown by the grinding test results, the test whetstone of this example had good surface roughness. This indicates that the grindstone produced according to the present invention is capable of good grinding for the processing required according to the surface roughness of the workpiece.

[Grinding test 2]

Using a test whetstone to which the present invention was applied, a grinding test using a silicon wafer as a work material was performed to evaluate the finish surface roughness, the grinding power, the grinding wheel consumption, and the amount of workpiece removal.

Table 5 and Table 6 show the raw materials and the mixing ratios of the respective test whetstones of Examples 3 and 4.

Raw material mixing ratio of Example 3 Grindstone: DIA # 3000 (3 ~ 6 ㎛) 36.12 wt% Inorganic adhesive: FJ-521 18.78 wt% (Tokiwa Electric Co., Ltd.) Glass frit (softening point 650 ℃) 14.69 wt% (Chemical composition: SiO ₂ 37 wt% Al ₂ O 8 wt% CaO 3 wt% Na ₂ O 14 wt% B ₂ O ₃ 38 wt%) Foaming agent: Diisopropylazodicarboxylate 1.41 wt% Solvent: Water 28.50 wt%

Raw material mixing ratio of Example 4 Grindstone: DIA # 3000 39.91 wt% Inorganic adhesive: FJ-521 17.99 wt% (Tokiwa Electric Co., Ltd.) Glass frit (softening point 650 ℃) 9.05 wt% (Chemical composition: SiO ₂ 37 wt% Al ₂ O 8 wt% CaO 3 wt% Na ₂ O 14 wt% B ₂ O ₃ 38 wt%) Foaming agent: Diisopropylazodicarboxylate 1.35 wt% Solvent: Water 31.21 wt%

(Examples 3 and 4)

Production procedure of test grindstones 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 mold having a length of 90 mm and a width of 70 mm.

3. Heated at 60 ° C. for 24 hours.

4. The solid produced to the above was taken out from the mold.

5. It was calcined at 850 ° C. for 7 hours in an air atmosphere.

6. Grinding stone composition after baking was the grindstone of Example 3, and became the grindstone volume fraction 20.3%, the binder volume ratio 18.9%, and the porosity 60.8%. In the grinding wheel of Example 4, the grindstone particles had a volume fraction of 18.6%, a binder volume of 11.3%, and a porosity of 70.1%.

7. In order to produce the cup-shaped grindstone of the shape shown in FIG. 2, 28 segment grindstone pieces of 20 mm in length, 3 mm in width, and 5 mm in height were produced. After the respective grinding wheel pieces 1 were cured, they were attached at equal intervals on the ring-shaped peripheral edge of the cup-shaped billet 2, and finished to produce cup-shaped grindstones of φ200 × t35 × h40mm (pictures of Figs. 3 and 4). See).

Grinding test condition; Grinding wheel size: Φ200 × t35 × h40 Cup grinding wheel Material: Silicon wafer Dimension: 200 mm (diameter) × 0.95 mm (thickness) Grinding fluid Name: Distilled water Flow rate: 12 liter / min Grinding machine type: Longitudinal flat grinding machine manufactured by Toshiba Type: UVG-380B Dressing condition: Dresser: WA # 3000 Grinding wheel Main speed: 1910 min-1 Table rotation speed: 50 min-1 Dress cutting: 20 ㎛ / min × 10 pass Sparking out: 30 sec Grinding method: Grinding method: Wet Infeed Grinding Wheel Spinning Speed: 1910 min-1 Table Spinning Spinning Speed: 50 min-1 Grinding Wheel Cutting: 20 μm / min Acquired Value: 40 μm Sparkout: 10 sec Grinding Number: 10

The method of obtaining each evaluation item is as follows.

Finish surface roughness Ra (micrometer) calculation order;

The finish surface roughness Ra was calculated | required by the calculation procedure similar to the grinding test 1 mentioned above.

Grinding power (kW);

The power consumption of the whetstone shaft motor is W, and is calculated by the equation: 612 × W / peripheral speed (60/100). The grinding wheel speed was also used as the speed.

Grinding consumption (µm);

It was calculated using the automatic measurement of the grinding dimensions of the grinding wheel.

Workpiece removal amount (mu m);

It was calculated using the automatic measurement of the grinding dimensions of the grinding wheel.

Test results

Wafer Grinding Count Ra (μm) Grinding power (kw) Example 3 Example 4 Example 3 Example 4 One 28 32 2.4 2.3 2 29 29 2.7 2.5 5 25 24 3.0 3.3 10 23 23 3.4 3.6

Wafer Grinding Count Whetstone Consumption (㎛) Wafer removal amount (㎛) Example 3 Example 4 Example 3 Example 4 One 0.4 0.4 39 40 2 0.6 0.4 37 40 5 0.7 0.9 36 39 10 1.3 1.2 37 38

Both Example 3 and Example 4 showed a removal amount close to the target removal amount of 40 µm with respect to the wafer removal amount. As for the grinding wheel consumption, abnormal consumption and stagnant consumption are not confirmed, and wafer removal is performed normally, indicating that grinding operation is performed smoothly. The abnormal value was not confirmed also in each characteristic of finish surface roughness Ra and grinding power Ft. The above results show that the grinding wheel of the Example can be appropriately and satisfactorily grinding even in the grinding operation | work which targets a silicon wafer.

Claims (10)

In a whetstone having a structure consisting of whetstone particles, a binder and pores, A porous bituminous grindstone characterized by having a binder formed by an inorganic adhesive and a glass frit, and pores formed by natural pores and a pore-forming agent. The method of claim 1, A porous bituminous grindstone, wherein the softening point of the glass frit is 300 to 900 ° C. The method of claim 2, A porous bituminous grindstone, wherein the softening point of the glass frit is 400 to 900 ° C. The method according to any one of claims 1 to 3, The grindstone particles include molten alumina grindstone particles, sol-gel alumina grindstone particles, silicon carbide grindstone particles, alumina-zirconia grindstone particles, cerium oxide grindstone particles, silica grindstone particles, CBN grindstone particles and diamond grindstone particles. A porous bituminous grindstone, characterized in that at least one selected from the group consisting of: A liquid mixture obtained by dispersing a grindstone, 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., and the pore forming agent is foamed to dry and solidify. A method for producing a porous bituminous grindstone, which is further calcined at 600 to 1000 ° C to obtain a bituminous grinding wheel. The method of claim 5, A method for producing a porous bituminous grindstone, characterized in that a liquid foamable pore-forming agent is used as the pore-forming agent. The method according to claim 5 or 6, A method for producing a porous bituminous grindstone, characterized in that a solid foamable pore-forming agent is used as the pore-forming agent. The method according to any one of claims 5 to 7, A method for producing a porous bituminous grindstone characterized by using a glass frit having a softening point of 300 to 900 占 폚. The method of claim 8, A method for producing a porous non-trifed whetstone, comprising a glass frit having a softening point of 400 to 900 ° C. The method according to any one of claims 5 to 9, The grindstone particles used are molten alumina grindstone, sol-gel alumina grindstone, silicon carbide grindstone, alumina-zirconia grindstone, cerium oxide grindstone, silica grindstone, CBN grindstone and diamond grindstone. A method for producing a porous grinding wheel, characterized in that at least one selected from the group consisting of particles.

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