Super Abrasive Wheel

Abstract

To provide a super abrasive grain wheel capable of suppressing chipping of an abrasive grain layer or running-away of a workpiece, suppressing variation in workpiece thickness more than conventional one does, and performing highly accurate grinding in double-head plane grinding work of an in-feed type.SOLUTION: A super abrasive grain wheel 100 used for double-head plane grinding work of an in-feed type comprises: a base metal; and an annular abrasive grain layer 20 secured to the base metal. The abrasive grain layer 20 includes a plurality of abrasive grain layer chips 22 arranged at intervals in a circumferential direction, and a resin part 24 that fills a space between the abrasive grain layer chips 22. The abrasive grain layer chips 22 are metal bond chips obtained by bonding abrasive grains through metal bonding. The resin part 24 contains a resin, an inorganic material non-metallic compound having modified Mohs hardness of 8 or higher, and a weakening agent. And a ratio of the inorganic material non-metallic compound in the resin part 24 is 15%-50% by mass.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a superabrasive wheel, and more particularly to a superabrasive wheel used in an infeed type double disc surface grinding. [Background technology]

[0002] As a grinding wheel having abrasive layer chips arranged on a base metal, Patent Document 1 discloses a spiral-type sound-reducing grinding wheel in which grinding wheel surfaces are provided at required intervals and inclined at a required angle, and the spaces between each inclined grinding wheel surface are filled with a resin material containing silicon carbide as a filler. In Patent Document 1, the spaces between the spirally arranged segments (abrasive layer chips) are filled with a resin material containing silicon carbide as a filler, thereby achieving a reduction in grinding noise and surface roughness.

[0003] Patent Document 2 discloses a rotary surface plate for a double-sided lapping machine, characterized in that diamond abrasive pieces, which are elongated rectangular rods with a predetermined thickness and width and are made by sintering metal powder and diamond powder, are fixed concentrically at a predetermined surface ratio to the mating surfaces of a pair of upper and lower rotary surface plates so that a gap is left between them.In Patent Document 2, by arranging the diamond abrasive pieces (abrasive layer chips) concentrically, they always come into contact somewhere even when the carrier is bent, suppressing snagging between the diamond abrasive pieces and preventing breakage.

[0004] On the other hand, double-disc surface grinding is a known grinding method in which the workpiece is passed between two wheels to grind both sides simultaneously. In double-disc surface grinding, the processing area is large, and since it is surface processing, it tends to be difficult for the abrasive grains to penetrate compared to general surface grinding. For this reason, an abrasive layer design is sometimes used in which abrasive layer chips are arranged to reduce the abrasive layer area and increase the surface pressure. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Publication No. 55-120464 [Patent Document 2] Japanese Patent Application Laid-Open No. 2004-243469 Summary of the Invention [Problem to be solved by the invention]

[0006] Wheels with an abrasive layer in which abrasive layer chips are arranged have problems such as the workpiece falling into the gaps between the abrasive layer chips or the workpiece being held unstable, causing the workpiece to move around, chipping of the abrasive layer, and poor workpiece accuracy.

[0007] The spiral-type noise-reducing grinding wheel in Patent Document 1 has a two-layer structure consisting of a metal bond layer composed of abrasive layer chips and a resin bond layer composed of a resin material filled between the abrasive layer chips. Only the metal bond layer contains superabrasive grains, while the resin bond layer does not contain superabrasive grains and is instead filled with silicon carbide. The resin bond layer filled with silicon carbide wears more than the metal bond layer, so it does not directly contact the workpiece and exerts a grinding action. It is said that only the metal bond layer performs the grinding process. However, this phenomenon only applies to cup-shaped wheels that utilize self-sharpening and when performing conventional grinding. In double-disc surface grinding, where self-sharpening is less effective, the resin bond layer is less likely to recede due to wear, resulting in processing resistance. As a result, while grinding noise can be reduced, it is difficult to suppress friction on the workpiece itself, making it difficult to achieve sufficient workpiece precision in double-disc surface grinding.

[0008] Furthermore, as mentioned above, wheels with an array of abrasive layer chips have the problem that the workpiece may fall into the gaps between the abrasive layer chips or the workpiece may not be held securely. In Patent Document 2, it is difficult to widen the spacing between the abrasive layer chips beyond a certain level, which reduces design freedom.

[0009] Although chipping of the abrasive layer can be suppressed by filling the gaps between the abrasive layer chips with resin, there is a problem that simply filling the gaps with regular resin, especially in double-disc surface grinding, causes resistance during processing, resulting in poor workpiece precision.

[0010] Under these circumstances, the object of the present invention is to provide a super-abrasive wheel that can suppress chipping of the abrasive layer and workpiece unsteadiness during in-feed double-disc surface grinding, reduce variation in workpiece thickness more than conventional methods, and enable high-precision grinding. [Means for solving the problem]

[0011] The present inventors have conducted extensive research to solve the above problems, and as a result have found that the following invention meets the above object, thereby completing the present invention.

[0012] The superabrasive wheel of the present invention is a superabrasive wheel used in the infeed method of double-disc surface grinding, and comprises a base metal and an annular abrasive layer fixed to the base metal, the abrasive layer having a plurality of abrasive layer chips spaced apart along the circumferential direction and a resin portion filling the spaces between the abrasive layer chips, the abrasive layer chips being metal-bonded chips in which superabrasive grains are bonded by a metal bond, the resin portion containing a resin, an inorganic non-metallic compound having a modified Mohs hardness of 8 or more, and a weakening agent, and the proportion of the inorganic non-metallic compound in the resin portion is 15% by mass or more and 50% by mass or less.

[0013] The inventors investigated the composition of the resin material used to fill the gaps between the abrasive layer chips and discovered that by filling the gaps between the abrasive layer chips with a resin material containing a specific inorganic non-metallic compound and a weakening agent in specific proportions, the resin material between the abrasive layer chips can be appropriately worn to a degree that does not create resistance during processing and does not wear out too much. The superabrasive wheel of the present invention has a resin portion composed of a specific resin material between the abrasive layer chips. During grinding, the resin portion wears appropriately so that it does not become flush with the abrasive layer chips, allowing the abrasive layer chips to recede while maintaining the appropriate height relationship between the resin portion and the resin portion. Furthermore, excessive wear of the resin portion does not create large steps, thereby preventing chipping of the abrasive layer, workpiece unrest, and workpiece snagging. This eliminates restrictions on the spacing of the abrasive layer chips, allowing for a high degree of design flexibility.

[0014] In the superabrasive wheel of the present invention, the particle size of the inorganic non-metallic compound is preferably 0.25 to 0.80 times the particle size of the weakening agent, which allows for more appropriate wear of the abrasive layer tip and the resin portion.

[0015] In the superabrasive wheel of the present invention, the particle size of the weakening agent is preferably 0.15 to 0.80 times the particle size of the superabrasive grains, thereby allowing the abrasive layer tip and the resin portion to be more appropriately worn.

[0016] In addition, in the superabrasive wheel of the present invention, the weakening agent preferably accounts for 10% to 20% by mass in the resin portion, the inorganic non-metallic compound preferably accounts for 30% to 40% by mass in the resin portion, and the particle size of the inorganic non-metallic compound preferably is 0.25 to 0.80 times the particle size of the weakening agent, thereby allowing the abrasive layer tip and the resin portion to be worn more appropriately.

[0017] In addition, in the superabrasive wheel of the present invention, the abrasive layer chips are preferably arranged at equal intervals along the circumferential direction, and each abrasive layer chip is arranged so as to extend linearly or curvedly from the inner periphery to the outer periphery of the abrasive layer, thereby enabling the workpiece to be machined with greater precision.

[0018] In the superabrasive wheel of the present invention, the weakening agent is preferably any one selected from carbon, molybdenum disulfide, and calcium fluoride.

[0019] In the superabrasive wheel of the present invention, the inorganic non-metallic compound is preferably any one selected from silicon carbide, silicon dioxide, and aluminum oxide. [Effects of the Invention]

[0020] According to the present invention, a superabrasive wheel is provided that can suppress chipping of the abrasive layer and workpiece unrest during in-feed double-disc surface grinding, reduce variation in workpiece thickness more than conventional methods, and enable high-precision grinding. [Brief explanation of the drawings]

[0021] [Figure 1] 1 is a plan view of a superabrasive wheel for double-disc surface grinding according to the present invention. FIG. [Figure 2] 1 is a front view of a superabrasive wheel for double-disc surface grinding according to the present invention. FIG. [Figure 3] FIG. 2 is a cross-sectional view of the AA end of FIG. [Figure 4] 1 is a diagram illustrating the state of a superabrasive wheel for double-disc surface grinding according to the present invention during grinding. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0022] The following describes in detail an embodiment of the present invention. However, the following description of the constituent elements is an example (typical example) of an embodiment of the present invention, and the present invention is not limited to the following content unless the gist of the present invention is changed. In this specification, when the expression "to" is used, it is used as an expression including the numerical value or physical property value before and after it. Furthermore, elements common to Figures 1 to 4 are given the same reference numerals, and their explanation may be omitted.

[0023] [Embodiment 1] Fig. 1 is a plan view of a double-disc surface grinding wheel 100 according to the present invention, Fig. 2 is a front view, and Fig. 3 is an AA end view of Fig. 1. As shown in Figs. 1 to 3, the superabrasive wheel 100 of the present invention comprises a base metal 10 and an annular abrasive grain layer 20 fixed to the base metal 10.

[0024] (base money 10) The base metal 10 is disk-shaped and has a mounting hole H that passes through the center of the circle in the direction of the axis C. The base metal 10 is made of a material that can hold the abrasive grain layer 20, and is made of a metal such as iron or aluminum.

[0025] (Abrasive layer 20) The abrasive layer 20 is an annular layer formed on the upper surface of the base metal 10 in the direction of the axis C, and having the same axis C as the base metal 10, and the upper surface of the abrasive layer 20 forms the grinding surface 20S. The abrasive layer 20 has a plurality of abrasive layer chips 22 arranged at intervals along the circumferential direction (X direction), and a resin portion 24 filling the spaces between the abrasive layer chips 22.

[0026] (Abrasive layer chip 22) The abrasive layer tip 22 is a metal-bonded tip formed by mixing superabrasive grains and a metal bond, sintering the mixture, and bonding the superabrasive grains together with the metal bond. This is the main part that processes the workpiece. The abrasive layer tip 22 has a structure containing 40% or more by volume of metal bond. The metal bond can be Cu, Sn, Co, Fe, W, Ni, or alloys thereof. The superabrasive grains are diamond and / or cubic boron nitride, and are dispersed in the metal bond. The particle size of the superabrasive grains is 35 to 200 μm, and the concentration is 25 to 125. These particle sizes and concentration levels make the tip suitable for double-disc surface grinding.

[0027] A plurality of abrasive layer chips 22 are arranged at equal intervals in the circumferential direction (X direction) in the abrasive layer 20. The abrasive layer chips 22 have a curved rectangular parallelepiped shape and are arranged so as to extend in a curved line from the inner periphery of the abrasive layer 20 to the outer periphery. In a plan view ( FIG. 1 ), the abrasive layer chip 22 has a rectangular shape with the long sides curved, and a corner 22A of the abrasive layer chip 22 contacts the inner periphery of the abrasive layer 20, and a corner 22B located diagonally from corner 22A contacts the outer periphery of the abrasive layer 20.

[0028] (Resin part 24) Resin portion 24 contains a resin, an inorganic non-metallic compound having a modified Mohs hardness of 8 or more (hereinafter simply referred to as "inorganic non-metallic compound"), and a weakening agent. Resin portion 24 does not contain superabrasive grains and is a portion that reduces movement of the workpiece during processing.

[0029] The resin constituting the resin portion 24 is not particularly limited, but may be, for example, a thermosetting resin such as an epoxy resin, a phenol resin, a urethane resin, or an imide resin.

[0030] The inorganic non-metallic compound constituting the resin portion 24 has the role of causing the resin portion 24 to retreat by falling off and rolling, and has a modified Mohs hardness of 8 or more (e.g., 8 to 13). Examples of such inorganic non-metallic compounds include silicon carbide, silicon dioxide, and aluminum oxide.

[0031] The proportion of the inorganic non-metallic compound in the resin portion 24 is 15% by mass to 50% by mass, and is set appropriately depending on the particle size of the inorganic non-metallic compound, the type of weakening agent, etc. The proportion of the inorganic non-metallic compound is preferably 20% by mass to 45% by mass, and more preferably 30% by mass to 40% by mass.

[0032] The particle size of the inorganic non-metallic compound is preferably 0.15 to 0.80 times the particle size of the weakening agent, more preferably 0.20 to 0.80 times, even more preferably 0.25 to 0.8 times, and even more preferably 0.25 to 0.6 times.

[0033] The weakening agent constituting the resin portion 24 serves as a fracture starting point for the resin portion 24 and serves to adjust the amount of recession of the resin portion 24. Examples of the weakening agent include carbon, molybdenum disulfide, and calcium fluoride.

[0034] The proportion of the weakening agent in the resin part 24 is set appropriately depending on the particle size of the weakening agent and the type of inorganic non-metallic compound, but is preferably 10% by mass to 40% by mass, more preferably 10% by mass to 30% by mass, and even more preferably 10% by mass to 20% by mass.

[0035] The particle size of the weakening agent is about 5 to 160 μm, and is preferably 0.25 to 0.80 times, and more preferably 0.25 to 0.6 times, the particle size of the superabrasive grains contained in the abrasive layer chip 22.

[0036] The resin portion 24 is usually composed of a resin, an inorganic non-metallic compound, and a weakening agent, and the total proportion of the resin, inorganic non-metallic compound, and weakening agent in the resin portion 24 is 95% to 100% by mass.

[0037] The dimensions of the wheel 100 are not particularly limited, but are set appropriately depending on the size of the workpiece, the grinding purpose, etc., with the outer diameter D of the base metal 10 being 100 mm to 10,000 mm, the width W of the abrasive layer 20 being 5 to 380 mm, the thickness of the abrasive layer 20 being 1 to 20 mm, and the width (length of the short side) of the abrasive layer tip being approximately 3 mm to 20 mm. Also, while FIG. 1 shows eight abrasive layer tips 22, this is not a limitation. The number of abrasive layer tips is set appropriately depending on the dimensions of the superabrasive wheel 100, the grinding purpose, etc., and is approximately 5 to 100.

[0038] (Grinding method using a double-disc surface grinding wheel) The superabrasive wheel according to the present invention is used for double-disc surface grinding using the infeed method, in which the wheels cut into the workpiece while oscillating the workpiece. In the infeed method, the wheels are arranged parallel to each other and the distance between the wheels is changed to process the workpiece. With the infeed method, the distance between the wheels is wider than the thickness of the workpiece at the start of processing, and processing is performed by changing the distance between the wheels and oscillating the workpiece while cutting the wheels into the workpiece, and at the end of processing, the distance between the wheels is reduced to the target dimensions of the workpiece. The superabrasive wheels are used in pairs and can be attached to the rotation axis of a double-disc surface grinder so that the grinding surfaces of the pair of superabrasive wheels are parallel to each other.

[0039] Specifically, as shown in FIG. 4, workpiece 30 held by a carrier (not shown) is inserted between a pair of parallel-arranged superabrasive wheels 100, 100, and workpiece 30 is oscillated while rotating superabrasive wheel 100 cuts into it. By using superabrasive wheel 100, the resin portion 24 can mitigate the wobbling of workpiece 30 that occurs at the oscillating end of workpiece 30 when it is inserted between superabrasive wheels 100, 100. Furthermore, resin portion 24 does not come into contact with abrasive layer tip 22, but retracts while maintaining an appropriate height positional relationship with abrasive layer tip 22. This improves workpiece precision.

[0040] The above describes the superabrasive wheel of the present invention using the superabrasive wheel 100 as an example, but the superabrasive wheel 100 is an example of the superabrasive wheel of the present invention, and the superabrasive wheel of the present invention is not limited to the superabrasive wheel 100.

[0041] For example, in the superabrasive wheel for double-disc surface grinding according to the present invention, the shape of the base metal is not limited to a disk shape, but may be a cup shape or the like.

[0042] The shape and arrangement of the abrasive layer chips are not limited to the configuration of the superabrasive wheel 100. For example, the abrasive layer chips may be arranged so as to extend linearly from the inner periphery to the outer periphery of the abrasive layer, and in this case, the abrasive layer chips may be arranged so as to be parallel to or inclined relative to the radial direction.

[0043] Furthermore, the abrasive layer is not limited to a configuration in which a plurality of abrasive layer chips are arranged in a single row. For example, the abrasive layer may have two or more rows of abrasive layer chips, such as a row of abrasive layer chips spaced apart in the circumferential direction so as to extend from the inner periphery of the abrasive layer toward the center of the width of the abrasive layer, and a row of abrasive layer chips spaced apart in the circumferential direction so as to extend from the center of the width of the abrasive layer toward the outer periphery of the abrasive layer. [Example]

[0044] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples as long as the gist of the present invention is not changed.

[0045] [Reference Example 1] Evaluation of wear volume by filler ratio in resin layer To evaluate the composition of the resin part, resin layers (structures without abrasive layer chips) with different amounts and particle sizes of inorganic non-metallic compounds and weakening agents were prepared. The particle sizes of the inorganic non-metallic compounds and weakening agents were determined by particle size distribution measurement based on the laser diffraction and scattering method, and corresponded to the cumulative 50% particle size from the fine particle side.

[0046] Next, a friction and wear test was carried out using a polishing machine on the combination of the resin layer and the blasted steel plate under the following conditions to measure the amount of wear, calculate the wear index, and investigate the optimal blending ratio for the resin layer. Note that the higher the wear index, the better. Resin layer dimensions: Φ40mm Spindle speed [rpm]: 200 ·Bottom plate rotation speed [rpm]: 200 Pressing pressure [N]: 50

[0047] (Reference example 1-1) A resin layer was prepared using carbon (particle size=50 μm) as a weakening agent, epoxy resin as a resin, and the amount, type and particle size of inorganic non-metallic compounds as A to P in Table 1.

[0048] [Table 1]

[0049] Table 1 shows the results of the friction and wear test of the prepared resin layers. From the results of Nos. A to F in Table 1, it was confirmed that the wear index increases when the inorganic non-metallic compound, weakening agent, and resin are contained, the modified Mohs hardness of the inorganic non-metallic compound is 8 or more, and the amount of the inorganic non-metallic compound is greater than 10 mass%. Furthermore, the results of Nos. E to J confirmed that when the amount of inorganic non-metallic compounds was 20 to 50 mass%, the wear index increased more than that of Nos. A to B, and when it was 30 to 40 mass%, the wear index increased further. From the results of Nos. K to P, it was confirmed that the wear index further increased when the particle size of the inorganic nonmetallic compound was 0.20 to 0.50 times the particle size of the weakening agent.

[0050] (Reference example 1-2) The resin layer was prepared using silicon carbide (modified Mohs hardness 13, particle size = particle size of weakening agent x 0.5) as the inorganic non-metallic compound and epoxy resin as the resin, with the amounts, types and particle sizes of weakening agents shown as Q to Z in Table 2. In Table 2, the particle sizes of the weakening agents are shown as a ratio to the particle size (100 μm) of the superabrasive grains in Example 1 described below.

[0051] [Table 2]

[0052] Table 2 shows the results of the friction and wear test of the prepared resin layers. From the results of Nos. Q to U in Table 2, it was confirmed that the wear index further increased when the amount of weakening agent was 10 to 20 mass %. Furthermore, the results of Nos. V to Z confirmed that the wear index further increased when the particle size of the weakening agent was 1 / 2 to 1 / 4 of the abrasive grain size.

[0053] [Example 1] A superabrasive wheel was manufactured with the resin portion shown in Table 3. The particle size of the superabrasive grains is determined by JIS B4130. The dimensions of the wheel and the composition of the abrasive layer chip are as follows: Wheel dimensions: outer diameter D: 305mm, abrasive layer width W: 75mm Composition of the abrasive layer chip: Super abrasive: synthetic diamond abrasive grain (SD, grain size 100 μm (grain size #140)), bond strength N, concentration 75, metal bond (width 15 mm, length 90 mm, arranged 45 mm apart)

[0054] [Table 3]

[0055] Next, a machining test was carried out using the superabrasive wheel under the conditions shown in Table 4, and the workpiece parallelism and current value were evaluated.

[0056] [Table 4]

[0057] (Evaluation method) · Workpiece parallelism (μm): The workpiece parallelism (μm) after grinding was measured using a micrometer. The lower the measurement value, the better the result. Current value (sharpness): The current value of the motor of the double-disc surface grinder to which the wheel is attached was used as an index of sharpness. The smaller the current value, the better the sharpness.

[0058] The results of the machining test are shown in Table 5. As shown in Table 5, Examples 1-1 and 1-2 showed improved workpiece parallelism and current value compared to the comparative example, and provided favorable results.

[0059] [Table 5] [Industrial Applicability]

[0060] The double-disc surface grinding wheel according to the present invention can be widely used in industrial fields where processing work is performed by double-disc surface grinding. [Explanation of symbols]

[0061] 10 base money 20 Abrasive layer 20S grinding surface 22 Abrasive layer chip 22A, 22B corner 24 Resin part 30 Work 100 Super Abrasive Wheel C axis center H Mounting hole D Outer diameter W width

Claims

1. A superabrasive wheel used in an infeed double-disc surface grinding system, a base metal and an annular abrasive grain layer fixed to the base metal; the abrasive layer has a plurality of abrasive layer tips spaced apart along the circumferential direction, and a resin portion filling spaces between the abrasive layer tips; The height of the resin portion is the same as the height of the abrasive layer tip, the abrasive layer tip is a metal bond tip in which superabrasive grains are bonded by a metal bond, the resin portion includes a resin, an inorganic non-metallic compound having a modified Mohs hardness of 8 or more, and a weakening agent; the proportion of the inorganic non-metallic compound in the resin portion is 15% by mass or more and 50% by mass or less; A superabrasive wheel, wherein the ratio of the weakening agent in the resin portion is 10 mass % or more and 20 mass % or less.

2. 2. The superabrasive wheel according to claim 1, wherein the particle size of the weakening agent is 0.25 to 0.80 times the particle size of the superabrasive grains.

3. 3. The superabrasive wheel according to claim 1, wherein the particle size of the inorganic non-metallic compound is 0.15 to 0.80 times the particle size of the weakening agent.

4. In the resin portion, The proportion of the inorganic non-metallic compound is 30% by mass or more and 40% by mass or less, 3. The superabrasive wheel according to claim 1, wherein the particle size of the inorganic non-metallic compound is 0.25 to 0.80 times the particle size of the weakening agent.

5. The abrasive layer tips are arranged at equal intervals along the circumferential direction, 3. The superabrasive wheel according to claim 1, wherein each of the abrasive layer chips is arranged to extend linearly or curvedly from the inner periphery to the outer periphery of the abrasive layer.

6. 3. The superabrasive wheel according to claim 1, wherein the weakening agent is any one selected from the group consisting of carbon, molybdenum disulfide, and calcium fluoride.

7. 3. The superabrasive wheel according to claim 1, wherein the inorganic non-metallic compound is any one selected from the group consisting of silicon carbide, silicon dioxide, and aluminum oxide.

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