TW200538237A - Porous vitrified grinding wheel and method for production thereof - Google Patents

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 mum.

Description

200538237 (1) IX. Description of the invention [Technical field to which the invention belongs] The present invention relates to a porous vitrified grinding stone and a method for manufacturing the same. [Prior art] The main types of grinding stones for grinding and honing can be exemplified by bonding agents such as vitrified grinding stones, thermosetting resin grinding stones, metal grinding stones, and electrode deposition grinding stones. Among them, vitrified grindstones are also widely used because of their sharpness, durability, and wide range of modifications: ’. In general vitrified grindstones, the abrasive material and the inorganic powders of clay, feldspar, glass frit and the like of the raw materials of the vitrified binder i are mixed with the secondary binder at the same time, and the mixture is filled in a mold. After the drying step, it is sintered at a high temperature of 600 ~ 1 300T :. On the one hand, a technique for manufacturing a grindstone using an inorganic adhesive hardened at a temperature lower than the sintering temperature has been disclosed (Patent Document 1). The specific φ system is described in the paragraph "〇 〇 05". The sintering temperature is 5 ~ 5 ~ 300, and the abrasive grain layer can be directly sintered to form the grinding stone lining. In addition, 50 to 30 parts by weight of mixed boron carbide and 50 to 10 parts by mass of ceramic material are added to 1 to 10 parts by weight of water glass, and the technology is sintered at 80 to 120 ° C after drying. Revealed (Patent Document 2). [Patent Document 1] Japanese Patent Laid-Open No. 2001-71268 [Patent Document 2] Japanese Patent Laid-Open No. 5 2-2 60 94 No. 200538237 (2) [Summary of the Invention] [Questions to be Solved by the Invention] Japanese Patent Laid-Open 200 1 -7 1 26 The grinding stone using inorganic adhesives sintered at low temperature as described in JP-A No. 8 has a lower bending strength than the vitrified grinding stone manufactured by ordinary methods. There are also issues with life. In addition, the production method described in Japanese Patent Application Laid-Open No. 52-26094 has a small amount of an inorganic substance to be added, and it is not a vitrified bonding agent which is mainly used for high-temperature sintering and cannot be expected to have sufficient strength. As mentioned above, the manufacturing of the inorganic grinding stone is reviewed from various aspects. In order to induce the characteristics of the required grinding stone, many methods and manufacturing conditions of the inorganic binder to be reviewed remain. In particular, in the production of porous vitrified grinding stones, in addition to good sharpness and high durability, consideration must be given to the uniformity of the grinding stone structure and the strength of the grinding stone. When organic porosity forming agents are used in the conventional vitrification manufacturing steps, the shape retention during sintering cannot be maintained, and due to problems such as large sintering shrinkage, φ porosity of a grindstone, especially with a porosity of 60% by volume or more Production of millstone is restricted. In addition, it is also conceivable to use porous inorganic materials to produce porous stones. Since the film walls of the inorganic hollow materials remain in the grindstone after sintering, there is a problem that the grinding resistance increases during grinding. On the one hand, in the production of the conventional vitrified grindstone, there is a problem that the grindstone structure is not easy to homogenize. Especially in a fine-grind grindstone with a particle size of less than 100 # m, the dispersion of pores tends to be uneven. In view of the above problems, an object of the present invention is to provide a porous vitrified grindstone manufactured using an inorganic adhesive and a foamable pore-forming agent, in particular 200538237 (3) a porosity of 60% by volume or more and / or abrasive grains A fine-pored grindstone having a particle size of less than 〇0 β m can have a uniform grindstone structure, a sharpened grindstone with sufficient durability and strength, and a method for manufacturing the grindstone. [Problem solving means] The porous inorganic vitrified grinding stone of the present invention that solves the above-mentioned problem is an abrasive particle, a binding agent, and a grindstone having a pore structure, and is formed by an inorganic bonding agent and a glass frit. The binder is characterized by having a natural pore and a pore formed by a pore-forming agent. In the porous vitrified grinding stone of the present invention, the softening point of the glass frit is preferably 300 to 900 ° C, and preferably 400 to 900 ° C. In addition, the grindstone of the present invention has at least one selected from the group consisting of a molten alumina-type grindstone, a colloidal gel-type grindstone, a silicon carbide-based grindstone, an alumina-hafnium oxide-based abrasive grain, a hafnium oxide-based grindstone, and silica. The abrasive grains of the system-type grindstone, CBN-type grindstone, and diamond-type grindstone are preferable. φ According to the method for producing a porous vitrified grindstone according to the present invention, a liquid mixture obtained by dispersing grindstone material, 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 at room temperature Drying and curing at ~ 300 ° C while foaming the pore-forming agent, and drying the cured product at 600 ~ 100 ° C to obtain vitrified grinding stones. In the production method of the present invention, the pore-forming agent may be a liquid foaming pore-forming agent or a solid foaming pore-forming agent. A glass frit having a softening point of 300 to 900 ° C, and preferably 400 to 900 ° C is preferably used. In addition, one or more abrasive grains are selected from the group consisting of melt oxidation-6-200538237 (4) aluminum-based grindstone, colloidal gel-based grindstone, silicon carbide-based grindstone, alumina-chromia-based abrasive grain, and oxidation A group of honing stones, silica-based grinding stones, C BN-based grinding stones, and diamond-based grinding stones. [Effects of the Invention] The present invention provides a bonding agent formed by using an inorganic adhesive and a glass frit, and a porous vitrified grindstone with approximately uniform pores formed by natural pores and a pore-forming agent, particularly having a porosity of 60 volumes The fine-grinding grindstone with a grain size of less than 1 00 // m above a uniform rate also has a uniform grindstone structure, a grindstone with good sharpness and sufficient durability and strength, and a manufacturing method thereof [for implementing the invention The best form] The grindstone of the present invention is a porous vitrified grindstone manufactured by casting a mixture containing a grinding material, an inorganic adhesive, a glass frit, and a pore-forming agent in a mold. The "porous vitrified grinding stone" in this specification means that it does not contain an organic primary binder, and an inorganic adhesive that is essentially a primary binder is used. The inorganic adhesive is also sintered with glass frit and contains a foaming agent. The formation of the pores and then the grindstone of the pores. According to the present invention, good pore formation is performed during the drying and solidification of the grindstone raw material mixture, and thereafter, by advancing vitrification with a glass frit, it is possible to manufacture a uniform grindstone structure, especially a fine and uniform pore structure, and Porous vitrified grinding stone with sufficient strength. First, each material used in the production of the mill of the present invention will be described. 200538237 (5) Inorganic adhesive, an inorganic substance that hardens at a relatively low temperature and is mainly formed into a sintered millstone shape. In this way, one or two or more kinds of silica, alumina, alumina, silica stone, aluminum phosphate, magnesium phosphate, etc. can be appropriately selected as the hardening of glass, silica colloid, aluminum phosphate, magnesium phosphate and other adhesives. Agent. Potassium silicate is, for example, water glass as an adhesive. Dehydrated silicate polymerizes and hardens. The ideal inorganic bonding is based on sodium silicate as the main component. As the pore-forming agent, any of inorganic pore-forming agents such as organic pore-forming agents can be used, and one of them is particularly preferably a foamable pore-forming agent. For example, polystyrene is suitable for use. In addition, as the property-forming agent used in the present invention, a solid foaming agent or a liquid foaming agent may be used at a proper ratio. It is desirable to use a liquid form, and the ideal liquid foaming agent is a general formula ROOC-N = >, where each R is a linear or branched dialkylazodicarboxylic acid of 1 to 4 ester. More desirable dialkyl diisopropylazodicarboxylate. In the present invention, azodicarboxylic acid esters can be used, which are dimethylazodicarboxylic acid esters, diacids, dipropylazodicarboxylic acid esters, and di-t-butylazo. . These dialkyl azodicarboxylates decompose and foam. Foaming pores are formed in the millstone structure. Its temperature is around 25 0 ° C, and it has no volatility at room temperature. It has recently started foaming. It has obtained ideal pores to be heated to 60. It is used to maintain the main components of inorganic adhesive, chromium oxide and silicon, and water glass. For agents such as silicic acid ions, it is also possible to use silicic acid and inorganic hollow from heating agents. Any one of spherical foaming foaming bubbles, two love foaming agents. J-COOR (the lower alkyl group of this formula) is other dialkyl ethyl azodicarboxy dicarboxylates, and is thermally decomposed by heating. Typical thermal decomposition b. It is better to attach ~ 200 ° C at 50 ° C 200538237 (6). The liquid foaming agent representing the dialkyl azodicarboxylic acid ester causes foaming at room temperature under an acidic solution, an alkaline solution, or when a phenol resin, a code resin, vinyl chloride, and a fatty acid metal salt are added. The inorganic adhesive solution used in the present invention is an alkaline solution that also causes foaming at room temperature, and casts the molded product's water. • The molded product is cured by the heat at this time. As in the present invention described above, the foaming of the liquid foaming agent and the curing of the inorganic adhesive can be started without applying a heating or cooling treatment at room temperature. The term "normal temperature" used in the specification B of the present application means the ambient temperature of the grinding stone material that can be simultaneously foamed with a liquid foaming agent and solidified with an inorganic adhesive without heating or cooling treatment, specifically 0 to 30 ° C. As described above, the present invention is preferably based on the use of an inorganic adhesive using an alkaline solution that can cause foaming at normal temperature to form bubbles and solidify the grindstone. The glass frit is an inorganic binder necessary for sintering vitrified grinding stones of the grinding stone structure, and its typical main chemical composition can use borosilicate glass. In addition, soda-lime glass, various crystallized glass, and the like may be used, and the invention is not limited to this. The ratio of the φ glass frit to the solid content of the inorganic adhesive can be appropriately changed in a range of 3: 1 to 1: 7, and 2.5: 1 to 1 ·· 6 is preferable. The softening point of the glass frit is preferably a temperature at which the glass frit can sufficiently soften and melt at a temperature lower than the specified sintering temperature during sintering, and for example, a temperature lower than the sintering temperature of 100 ° C is desirable. However, if the temperature difference between the sintering temperature and the softening point is too large, it may be uncomfortable to produce cracks or the like in grinding stone manufacturing, and the temperature difference is preferably 30 ° or less. Abrasive particles, suitable for use are fused alumina-based abrasive particles, colloidal gel-based abrasive particles, silicon carbide-based abrasive particles, alumina-chromium oxide-based abrasive particles, oxide honing-9-200538237 (7) particles, silica-based Super abrasive grains such as abrasive grains, CBN-based abrasive grains and diamond-based abrasive grains. According to the grinding conditions, one or more types of abrasive grains suitable for use can be selected from the above. The grain size of F4 can be used. Particle size) ~ average particle diameter up to 0.1 # m. As appropriate, F4 (in accordance with the "B type particle size indication of" types of coarse particles "described in" JIS R 600 1 Grinding Materials for Grinding Honing Materials ") ~ average particle diameter 0.2 // m can be used. It is particularly suitable to use the particle size shown in the "resistance test method" in "Type of Fine Powders for Precision Honing" described in "1000" (compliant to "JIS R 6 00 1 Grinding Material for Honing Materials for Grinding Stones") , Particle size distribution when accumulated 50% height 1K5 ± 1.0 // m) ~ average particle diameter 0.5 // m. Next, the manufacturing method of the grindstone of this invention is demonstrated. The manufacturing method of the grinding stone of the present invention includes the steps of mixing and dispersing the above-mentioned raw materials of the grinding stone in an aqueous solution, pouring the raw material into a mold for grinding stone molding, and pouring the liquid mixture of φ pouring at normal temperature (0 ~ 30 ° C). ~ 3 0 0 ° C The step of drying and solidifying and foaming at the same time, and the melting temperature of the dried solidified material above the glass frit, specifically, the sintering step of 600 ~ 100 ° C. In this method, casting is performed. The molding is to obtain a high degree of dispersibility of the mixed raw materials, and to form a more uniform millstone structure. The manufacturing method of the present invention using the above raw materials is dried and solidified at room temperature after casting at a normal temperature of ~ 3 00 ° C The hardened inorganic adhesive is foamed to form artificial bubbles together with the foamable bubble forming agent. This advantage is to achieve the disadvantages in the manufacture of the grindstone that prevents casting. That is, when hardened, it is mixed -10- 200538237 (8) The moisture contained in the product evaporates to dry the molded product, which has the effect of generating cracks during the drying. According to the manufacturing method of the present invention, the liquid mixture forms bubbles by the foaming effect of the pore forming agent during curing, The water in the liquid mixture escapes to form a cavity. Therefore, the pore forming agent can form uniform pores in the liquid mixture and prevent cracking during production. This effect is more effective than using a solid foaming agent when it is dispersable. The method of the liquid foaming agent is particularly advantageous. B Inside the millstone manufactured according to the present invention, natural bubbles are formed during the preparation of the liquid material and dehydrated traces form natural pores, and the added foaming agent is the source. The natural air bubbles, the bubbles formed by the foaming agent are larger than the natural pores. These two bubbles can be evenly dispersed in the inside of the millstone, and the millstone can hold a uniform high porosity millstone In addition, the above-mentioned low-temperature drying and curing treatment can prevent cracking or deformation of the grindstone burnt material during subsequent high-temperature sintering. The raw material does not contain an organic primary binder to prevent sintering. The odor in the medium and the cracking caused by the φ mixture once, and the moisture in the grinding stone is completely dried can also prevent the abnormal shape caused by the residual moisture in the sintering. Next, the above curing step, The mixed molding is sintered at 600 ~ 1 000 ° C. Here, the glass frit and the inorganic adhesive cause a chemical reaction to increase the strength. That is, according to the present invention, the grindstone is manufactured using the glass frit. After the inorganic adhesive is hardened, it is more than 600 ~ 1 000 ° C sintered glass frit is softened and melted, glass frit can improve the binding force with abrasive particles and cause chemical reaction with inorganic adhesion. Vitrified grindstone. In contrast, vitrified grindstone manufactured by the method using only inorganic adhesive Compared with the present invention, the bending strength is low, the grinding force holding force is insufficient, and the service life of the grinding stone becomes -11-200538237

short. As described above, the desired properties of the porous vitrified grindstone can be produced by sequentially activating each characteristic of the inorganic adhesive, glass frit, and bubble-forming agent in the steps of drying and curing (hardening) and sintering in sequence. The composition of the grindstone can be manufactured in a range of 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. In addition, the binder ratio is the volume ratio of the inorganic adhesive + glass frit minus the abrasive and porosity ratios from 100%. The present invention can provide a porous vitrified grindstone with the characteristics of low grinding resistance and good surface roughness. The grindstone of the present invention can be used well in general grinding conditions, barrel grinding, surface grinding, inner surface Grinding, general grinding, etc. In particular, the grinding stone of the present invention can be used well for grinding and honing iron-based materials, and can also be used well for non-ferrous silicon wafers, superhard, alumina, sapphire, quartz, and carbide materials. Grinding and honing of hard and brittle materials such as aluminum, nitride materials, various glass and ceramic materials. [Embodiments] The following examples and comparative examples are used to illustrate the present invention. These are examples of the possibility and usefulness of the present invention. [Bending strength test] The grinding stone (Example 1) applied to the present invention was compared with the grinding stone (Comparative Example 1) using only an inorganic adhesive as a binder, and its bending strength was compared. -12- 200538237 (10) Table 1 and Table 2 show the raw materials and mixing ratio of each test grinding stone

37.3 wt% 3 0.1 w t% abrasive particles; W A # 1 5 0 0 inorganic adhesive; F J-5 2 1 (manufactured by Tokiwa Electric Co., Ltd.) glass frit (softening point 65 0 ° C) 2.9 wt%

(Chemical composition: Si 02 3 7 wt% A12 〇8 wt% C a O 3 wt% N a 2 〇1 4 wt% B2 〇3 38 wt%) Foaming agent; Diisopropylazodicarboxylate 2 · 3 wt% solvent; water 27.4 wt% [Table 2] abrasive particles; WA # 1 5 00 3 8.4 wt% inorganic adhesive; FJ-52 1 3 1 · 〇wt% (manufactured by Tokiwa Electric Co., Ltd.) ) Foaming agent; diisopropylazodicarboxylate 2.3 wt% solvent; water 28.3 wt% (Example 1) Manufacturing sequence of the test millstone of Example 1: -13- 200538237 (11 ) 1 · Evenly mix the raw materials described above. 2. Pour the slurry-like mixture into a mold of 120 x 300 mm. 3. Heat at 60 ° C for 72 hours. 4 · Take out the solid material obtained by heating from the mold. 5. Sintered at 90 ° C for 7 hours. 6. After sintering, a 120 x 30 丄 rectangular grindstone was produced in the cutting thickness direction. (Comparative Example 1) The procedure for making the test grindstone of Example 1 was: 1 Evenly mix the raw materials described above. 2 · Pour the slurry-like mixture into a mold of 120 x 3 0 mm 3. Heat at 60 ° C for 72 hours. 4. After sintering, make 1 20 X 3 0 in the cutting thickness direction X 4〇 Hinged square grindstone. The evaluation procedure is in accordance with JIS standard (bend strength test method for fine ceramics R 2004). Each test grindstone is subjected to a 3-point bending strength at a support distance of 100 mm at a load of 1.0 mm / min. The test grindstones were made with 3 average cymbals for comparison. Table 3 shows the test results of flexural strength. Type. 40 mm type. 1601 mm, 3 deceleration speeds, -14-200538237 (12) [Table 3 Strength 値 (MPa) Example 1 30 Comparative Example 1 The sheet blisters at 10 are shown in Table 3. The test grindstone of Example 1 has a bending strength three times that of Comparative Example 1. This is the glass added according to the present invention. The result of sintering at 900t at high temperature. Fig. 1 is an electron microscope of a test millstone produced in Example 1. .When you look at the state of the tissue, it is known that it forms fine pores with uniform pores from the fine natural pores and the liquid hair agent at the same time. [Grinding test 1] The test grinding stone (Example 2) suitable for use in the present invention is used for grinding (Measurement surface roughness (Ra, Rz). (Example 2) The procedure for making the test grindstone of Example 2 is as follows: 1) The above-mentioned raw materials are uniformly mixed. 2) The slurry-like mixture is poured into Model with an outer diameter of 20.5 mm and a hole diameter of mm. 3. Heat at 60 ° C for 72 hours. 4 Take out the solids obtained from the heating. -15- 50 200538237 (13) 5. At 900 ° C Sintering for 7 hours. 6. After sintering, retouching was performed to produce a 1 A grindstone of 0 205 x t 10x h 50 mm. Table 4 shows the grinding test conditions. [Table 4] Grinding test conditions

Grinding stone size: Material to be cut: Size: Grinding fluid name: 0 205 χ t 1 〇χ h S55C (hardened material 1 00 mm (length) X Clay cut NS 201 50 mm 1A grinding stone 5 8HRC) 5 mm (Width) Concentration · 2% Flow rate: 1 5 liters / min. Grinding disc type: Horizontal axis flat grinding disc made by Japan Okaki Works, Ltd. Type: CNC-52B (7.5 kw)

Dressing conditions: Dresser: Sharp-mouthed dressing stone peripheral speed: 33m / s Dressing rate: 0.05 mm / Rotary dressing feed: 0.001 mm / stroke χ 10 stroke travel Grinding method: Planar moving grinding stone peripheral speed: 33m / s turntable speed: l67m / s approach speed: 2 mm / stroke grinding feed amount: 0.001 mm / stroke grinding amount: 0 · 0 2 mm control: 1 stroke -16- 200538237 (14) modified surface roughness (Ra, Rz) calculation program [Ra] Centerline average rough seam degree (Ra) is based on the thick seam curve to the centerline direction to extract the length 1 part, and the centerline of the sampled part is the X axis, The direction of the vertical magnification is the γ axis, and when the rough curve is expressed by y = f (X) ', it is obtained by the following formula and expressed in micrometers (// m).

[Rz] The surface roughness related to the modified surface of the test grindstone 'was measured at a 10-point average roughness Rz. The 10-point average roughness Rz is drawn from the rough curve to its average line, and only the reference length is taken. 'Measure from the average line of the sampling part to the direction of the vertical magnification, and find the height Yp The average 値 of φ absolute 値 is the sum of the absolute 値 of the elevation Υν from the bottom of the 5th trough. In this embodiment, 'R ζ is more than 0 · 50 and " m, and 1 · 0 # m, and it is distinguished by a reference length of 0.8 mm and an evaluation length of 4 mm. Grinding test results The modified surface roughness (Ra'Rz) of the test grindstone of this example is as follows.

Ra 0.0 14 // m

Rz 0.102 ^ m -17- 200538237 (15) The test grindstones of the examples of the present invention have good surface roughness as shown by the grinding g test results. This is a grindstone manufactured in accordance with the present invention, and it shows that it can be ground well because of the processing required for the surface roughness of the material being cut. [Grinding test 2] Using a test grindstone suitable for the present invention, a grinding test was performed on a silicon wafer as a material to be cut, and the surface roughness, grinding power, grinding stone consumption, and material removal amount were evaluated. The votes and Table 6 show the materials and mixing ratios of the test grindstones of Examples 3 and 4. [Table 5] Abrasive particles; DIA # 3 000 (3 ~ 6 # m) 36.12 wt% inorganic adhesive; FJ-5 2 1 1 8.7 8 wt% (manufactured by Tokiwa Electric Co., Ltd.) glass frit (softening point) 650 ° C) 14.69 wt% (chemical composition: Si 02 3 7 wt%

Al2 〇8 wt% Ca 0 3 wt% Na2 〇14 wt% B 2 〇3 3 8 wt%) blowing agent; diisopropyl azo dicarboxylate 1.41 wt% solvent; water 2 8.50 0 wt% • 18 200538237 (16) [Table 6] 3 9.91 wt% 17.99 wt% 9.05 wt% 1.35 wt% 3 1.21 wt% abrasive grains; DIA # 3000 (3 ~ 6 // m) inorganic adhesive; FJ-521 (Japanese Made by Tokiwa Electric Co., Ltd.) Glass frit (softening point 65 0 ° C) (chemical composition: Si 02 3 7 wt% A12 O 8 wt% C a O 3 wt%

Na2 0 14 wt% B2 O3 38 wt%) foaming agent; diisopropylazodicarboxylic acid vinegar solvent; water (Examples 3 and 4) Production sequence of the test millstones of Examples 3 and 4: 1・ Mix the ingredients mentioned above uniformly. 2 · The slurry-like mixture is poured into a model with a length of 90 mm and a width of 70 mm. 3 · Heat at 60 ° C for 7 2 hours. 4 · Take out the solid material obtained by heating from the mold. 5. Sintered at 8 5 ° C for 7 hours. 6. The composition of the grindstone after sintering. In the grindstone of Example 3, the volume ratio of the abrasive particles was 2 0.3%, the volume ratio of the binder was 18 · 9%, and the porosity was 60%. 8%. The grinding stone of Example 4 has an abrasive particle volume ratio of 18.6%, a binder volume ratio of 113% -19-200538237 (17), and a porosity of 7 0.1%. 7. It is manufactured as shown in Figure 2 For the cup-shaped grinding stones of the shape, 28 fan-shaped grinding stones with a length of 20 mm, a width of 3 mm, and a height of 5 mm were made for each gas 1 according to the above-mentioned production sequence. On the ring-shaped periphery of the cup-shaped lining (2), a cup-shaped grinding stone of 0 200 XG 5 X h 40 mm is manufactured by modifying (see photos in Figs. 3 and 4).

-20- 200538237 (18) [Table 7] Grinding test conditions Grinding stone size: 0 205 > < t35xh40mm Cup type grindstone ^ Material to be cut: Sand wafer size: 200 mm (diameter) X 0.9 mm ( Thickness) Grinding fluid name: Distilled water flow rate: 12 liters / min. Grinding disc type: Vertical axis surface grinding disc made by Toshiba Machinery Co., Ltd.

Type: UVG -3 80 B Modification conditions: Modified material: WA # 3 0 0 0 Grinding wheel peripheral speed: 1910 mirT1 Turntable peripheral speed: 50 mirT1 Modified feed: 20 // m / minx 10 stroke grinding method: Wet cut-in grinding grinding stone peripheral speed: 1910 mirT1 • Turntable turning peripheral speed: 50 mirT1 Grinding stone feed amount: 20 / zm / min Grinding amount: 40 // m Control: 1 0 sec. Number of grinding pieces: The evaluation method for each item of 〇 is as follows _ · The modified surface roughness Ra (// m) calculation program-21-200538237 (19) The modified surface roughness Ra is determined by the same procedure as the above grinding test 1 ( kW): The power consumption of the grindstone shaft motor is W, which is obtained by the formula: 612xW / peripheral speed (60/100). As the peripheral speed, the above-mentioned grinding stone peripheral speed is used. Grinding Stone Consumption U m): It can be obtained by the automatic measuring machine for grinding size using a grinding disc. Removal amount of material to be cut (// m): It can be obtained by the automatic measuring function of the grinding size using a grinding disc. test results:

Wafer grinding number Ra (// m) Grinding power (k W) Example 3 Example 4 Example 3 Example 4 1 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 -22- 200538237 (20) [Table 9] Number of wafer grinding pieces, grinding stone consumption (// m), wafer removal amount (V m) Example 3 Example 4 Example 3 Example 4 1 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

Regarding the removal amounts of both the wafers of Examples 3 and 4, it is shown that the target removal amount is close to 40 // m. Relevant millstones disappeared without abnormal consumption and consumption stagnation. Wafer removal proceeded normally, indicating smooth grinding operations. The characteristics of modified surface roughness (Ra) and power consumption (Ft) are not unusual. From the results described above, the grinding stone of the embodiment is capable of performing a suitable and good grinding operation on the wafer. [Brief description of the drawings] [Fig. 1] An electron microscope photograph of the grindstone structure of the test grindstone produced in Example 1. [Fig. [Fig. 2] A schematic cross-sectional view of a cup-shaped grindstone of Examples 3 and 4. [Fig. 3] A photograph of a cup-shaped grindstone produced in Examples 3 and 4 taken from the front. [Fig. 4] An enlarged photograph taken from the grinding stone periphery of the cup-shaped grinding stone of Fig. 3. [Fig. -23- 200538237 (21) [Description of main component symbols] 1 Grinding stone piece 2 Cup-shaped grindstone lining 3 Grinding stone honing surface

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Claims (1)

200538237 (1) 10. Scope of patent application1. A porous vitrified grindstone is a grindstone with a structure formed by abrasive grains, a binder and pores, and is characterized by an inorganic adhesive and a frit. Forming a binding agent, and pores formed by a natural pore and a pore-forming agent. 2 · The porous vitrified grinding stone according to item 1 of the patent application scope, wherein the softening point of the glass frit is 300 ~ 900 ° C. 3. The porous vitrified grinding stone according to item 2 of the patent application range, wherein the softening point of the glass frit is 400 ~ 900 ° C. 4 · The porous vitrified grinding stone according to any one of claims 1 to 3, wherein the abrasive particles are at least one selected from the group consisting of molten alumina-based abrasive particles, colloidal gel-like abrasive particles, and silicon carbide system. Groups of abrasive grains, alumina-rhenium oxide abrasive grains, hafnium oxide abrasive grains, silica abrasive grains, C BN abrasive grains, and diamond abrasive grains. 5 · A method for manufacturing a porous vitrified grindstone, which is characterized in that a liquid mixture obtained by dispersing abrasive particles, an inorganic adhesive, a glass frit, and a pore-forming agent in water is cast into a model, and the mixture in the model is at room temperature ~ Drying and curing at 3 00 ° C while foaming the pore forming agent, sintering the dried cured product at a temperature of 600 ~ 1000 ° C to obtain vitrified grinding stone. 6. The manufacturing method according to claim 5 in which the pore-forming agent is a liquid foaming pore-forming agent. 7. The manufacturing method according to claim 5 or 6, wherein the pore-forming agent is a solid foaming pore-forming agent. 8 · If the manufacturing method of any of the items in the scope of patent application 5-7, • 25- 200538237 (2) It uses a softening point of 3 00 ~ 9. If the scope of the patent application is 400 ~ 900 ° C Glass rice 10. For example, the scope of patent application_ / where the abrasive particles are at least one kind of glass frit selected from abrasive particles, silicon carbide-based abrasive particles, oxygen abrasive particles, silica-based abrasive particles, CBN 900 ° C. The manufacturing method according to item 8, which uses softening; the manufacturing method according to any one of items 5 to 9, melting alumina-based abrasive particles, colloidal gelatinized aluminum-chromium oxide-based abrasive particles, thorium oxide-based abrasive particles, and diamonds Groups of abrasive particles. -26-