JP3958428B2 - Grinding tool - Google Patents

Description

[0001]
[Technical field to which the invention belongs]
The present invention relates to a grinding tool used for grinding and cutting a curved surface shape such as a fine groove shape or an aspherical shape.
[0002]
[Prior art]
Conventionally, a diffractive lens and a diffraction grating may be manufactured by, for example, a glass mold using a mold that has been precision processed in advance. In this case, this mold is obtained by performing cutting or burnishing on a substrate such as a resin on which a metal thin film is formed by electroless Ni plating or vacuum deposition of aluminum.
[0003]
FIG. 4 shows an example of manufacturing a diffractive lens mold by conventional cutting. In this example, the base material 50 that is the base of the diffractive lens mold is rotated around an axis 60 by a spindle motor (not shown). Then, the single crystal diamond cutting tool 51 is applied to the processing surface of the substrate 50, and the material forming the processing surface is cut and removed by the single crystal diamond cutting tool 51. As a result, a fine groove shape is formed on the surface to be processed of the substrate 50.
[0004]
FIG. 5 shows an example of manufacturing a diffraction grating mold by conventional burnishing. In this example, the base material 52 which is the base of the diffraction grating type moves forward and backward in a direction perpendicular to the paper surface by a slide table (not shown). Then, the formed diamond tool 53 polished into a shape in which two cones are joined at the bottom surface thereof is pressed against the surface of the base material 52, and the formed diamond tool 53 is rotated so that the shape is applied to the surface of the base material 52. Transcribed. As a result, fine grooves are formed on the processed surface of the substrate 52.
[0005]
These diffractive lenses and diffraction gratings may be manufactured by directly cutting a resin block with a diamond bit 51 or burnishing with a molded diamond tool.
[0006]
However, according to the conventional machining method, the same working blade of the same tool is used in both the case of cutting using the diamond cutting tool 51 and the case of burnishing using the formed diamond tool 53. Is always in contact with the surface to be machined, the load on the working cutting edge is large, and the working cutting edge is easily worn. For this reason, according to the conventional processing method, the type of material to be processed is limited to relatively soft materials such as copper, aluminum, electroless Ni plating, resin, etc., and optical glass, cemented carbide, steel, cemented carbide It has been very difficult to process relatively hard materials such as alloys.
[0007]
On the other hand, an aspheric lens may also be manufactured by a glass mold method. In this case, a mold (aspheric mold) for manufacturing the mold is applied to the surface of the base material from which the mold is formed at a 45 ° angle while rotating a cylindrical grindstone (grinding tool) at a high speed, The vicinity of the edge is manufactured by scraping the surface of the substrate. As this cylindrical grindstone, a resin bond grindstone, an electrodeposition grindstone, or the like is used.
[0008]
Here, the resin bond grindstone is obtained by, for example, fixing a bond material mixed with diamond abrasive grains around a cylindrical grindstone base material. The electrodeposition grindstone is, for example, a diamond abrasive grain fixed in the vicinity of the tip of the grindstone base material by a metal plating layer.
[0009]
However, these cylindrical grindstones (resin bond grindstones, electrodeposited grindstones, etc.) can easily drop off or wear out diamond abrasive grains at the edge during processing of the workpiece due to the placement of diamond abrasive grains. There is a drawback that the shape and surface accuracy of the workpiece become unstable. Therefore, it could not be used for ultraprecision machining.
[0010]
[Problems to be solved by the invention]
The present invention has been made in view of the above points, and an object of the present invention is to provide a grinding tool that suppresses falling off of a grindstone and enables processing on a relatively hard material. It is an object of the present invention to provide a grinding tool that can be used for processing of a diffractive lens type, a diffraction grating type, a diffraction grating itself, etc. that require grooving, and for processing a curved surface such as a spherical surface or an aspherical surface.
[0011]
[Means for Solving the Problems]
Such an object is achieved by the present inventions (1) to ( 4 ) below.
[0012]
(1) A grinding tool comprising a grindstone base material having a rotating body, and a plurality of grindstones that are disposed over the entire outer periphery of the tip portion of the grindstone base material, and each of which has a square cross section made of a prismatic diamond,
As for the said grindstone, one diagonal in a cross section crosses the outer peripheral surface of the said grindstone base material, and has faced the radial direction of the said grindstone base material, and another one diagonal is inside the outer peripheral surface of the said grindstone base material. A grinding tool characterized by being fixed to be positioned.
[0013]
(2) A part of the grindstone is exposed outside the outer peripheral surface of the grindstone base material, and the remaining part is buried in the grindstone base material, and the maximum width in the circumferential direction in the grindstone embedding portion is set. L ₁ , satisfying the relationship L ₁ / L ₂ ≧ 1.2, where L ₂ is the maximum circumferential width of the exposed portion of the grindstone ,
The grinding tool according to (1), wherein the grinding wheel base is rotated and the workpiece is ground by an edge formed on an exposed portion of the grinding wheel.
[0014]
(3) A part of the grindstone is exposed outside the outer peripheral surface of the grindstone base material, and the remaining part is buried in the grindstone base material, and the maximum width in the circumferential direction in the grindstone embedding portion is set. L ₁ , satisfying the relationship of 12 ≧ L ₁ / L ₂ ≧ 1.4, where L ₂ is the maximum circumferential width of the exposed portion of the grindstone ,
The grinding tool according to (1), wherein the grinding wheel base is rotated and the workpiece is ground by an edge formed on an exposed portion of the grinding wheel.
[0015]
(4) The said grindstone is arrange | positioned at substantially equal intervals along the circumferential direction of the outer peripheral surface of the said grindstone base material so that the longitudinal direction may become parallel to the center axis | shaft of the said grindstone base material. The grinding tool according to any one of 1) to (3) .
[0020]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the grinding tool of the present invention will be described in detail based on preferred embodiments shown in the accompanying drawings.
[0021]
FIG. 1 is a top view showing an embodiment of the grinding tool of the present invention, and FIG. 2 is a cross-sectional view taken along line AA in FIG. As shown in these drawings, the grinding tool 1 of the present invention has a substantially cylindrical (rotary body) grindstone base 2 and a rod shape disposed over the entire outer periphery of the tip of the grindstone base 2. A plurality of grindstones 4 are provided.
[0022]
The grindstone substrate (grindstone support base) 2 is made of, for example, alloy tool steel SKS. The dimensions of the grindstone substrate 2 are, for example, a diameter of 1.8 mm and a length of 8 mm.
[0023]
A plurality of grooves 3 formed by, for example, electric discharge machining are formed on the outer peripheral portion of the tip portion of the grindstone base material 2. A grindstone 4 to be described later is inserted and fixed in each of these grooves 3. In the present embodiment, the grooves 3 are arranged at substantially equal intervals along the circumferential direction of the outer peripheral surface of the grindstone base 2 so that the longitudinal direction thereof is parallel to the central axis 6 of the grindstone base 2. ing. Further, the upper end of the groove 3 in FIG. 2 is open to the front end surface of the grindstone base 2.
[0024]
Each grindstone 4 is a diamond tip made of diamond, and the shape thereof is a rod shape (columnar shape). The cross-sectional shape of the grindstone 4 is preferably a polygon, and in the illustrated embodiment, it is a square (quadrangle). The dimensions of the grindstone 4 are, for example, 0.2 mm × 0.2 mm square and a length of about 2 mm.
[0025]
The grindstones 4 are arranged at substantially equal intervals along the circumferential direction of the outer peripheral surface of the grindstone base 2 so that the longitudinal direction thereof is parallel to the central axis 6 of the grindstone base 2.
[0026]
In this invention, it has the characteristics in arrangement | positioning of the grindstone 4 with respect to the grindstone base material 2. FIG. This will be described in detail below.
[0027]
A part of the grindstone 4 is exposed to the outside of the outer peripheral surface 5 of the grindstone base 2, and the rest is embedded in the grindstone base 2, that is, in the groove 3. As shown in FIG. 1, when the maximum circumferential width of the embedded portion 41 of the grindstone 4 is L ₁ and the maximum circumferential width of the exposed portion 42 of the grindstone 4 is L ₂ , L ₁ / L ₂ > 1. Satisfy the relationship.
[0028]
In other words, in the grindstone 4, one diagonal line 43 in the cross section crosses the outer peripheral surface 5 of the grindstone base material 2 (particularly, in the radial direction of the grindstone base material 2), and the other one diagonal line 44 is the grindstone base. It is fixed so as to be located on the inner side (center side) of the outer peripheral surface 5 of the material 2.
[0029]
By arranging the grindstone 4 so as to have the above positional relationship, the portion of the embedded portion 41 having the maximum width L ₁ exhibits the same function as the wedge, and prevents the grindstone 4 from moving in the outer circumferential direction. . As a result, the adhering force of the grindstone 4 to the grindstone substrate 2 is increased, and the falling of the grindstone 4 is prevented or suppressed.
[0030]
Further, the maximum width L ₂ of the maximum width L ₁ and the exposed portion 42 of the embedded portion 41, further, it is preferable to satisfy L ₁ / L ₂ ≧ 1.2 the relationship, 12 ≧ L ₁ / L ₂ It is more preferable to satisfy the relationship of ≧ 1.4.
[0031]
The reason for providing the lower limit of L ₁ / L _2, when L ₁ / L ₂ is less than this lower limit, for example when an excessive stress or impact grinding tool 1 is applied, easily occurs falling off of the grinding wheel 4 Because it becomes.
[0032]
Further, because, if L ₁ / L ₂ exceeds the upper limit, the amount of projection of the exposed portion 42 of the grinding wheel 4 is reduced, the contact length of the workpiece to provide the upper limit of L ₁ / L ₂ Becomes extremely short, and wear of the grindstone 4 is accelerated (life is shortened).
[0033]
FIG. 3 shows a grinding tool 10 as a comparative example. In this grinding tool 10, as in the grinding tool 1 of the present invention, a plurality of grinding stones 40 having the same shape as the grinding stone 4 are fixed in the groove 30 over the entire outer periphery of the tip of the grinding stone base 20. Each of the grindstones 40 is arranged with a 45 ° offset from that of the grinding tool 1 of the present invention. That is, the maximum width L ₁ of the embedded portion 41 of the grindstone 40 and the maximum width L ₂ of the exposed portion 42 are equal, and L ₁ / L ₂ = 1.
[0034]
In such an arrangement of the grindstone 40, the bonding force of the grindstone 40 to the grindstone base material 20 depends only on the adhesive force between the outer surface of the grindstone 40 and the inner surface of the groove 30, and therefore compared with the grinding tool 1 of the present invention. The whetstone 40 is likely to fall off.
[0035]
Next, an example of a manufacturing method (assembly method) of the grinding tool 1 will be described.
[1] Eight whetstones 4 made of prismatic diamond of 0.2 mm × 0.2 mm × 2 mm are produced.
[0036]
[2] Grinding wheel base material 2 having a diameter of 1.8 mmφ × length of 8 mm is cut out from a block of alloy tool steel SKS, and eight grooves 3 are formed on the outer peripheral surface thereof at equal intervals (interval of 45 ° central angle) by electric discharge machining. Form. In this case, the shape of the groove 3 can be, for example, the same shape as the embedding portion 41 of the grindstone 4, a shape approximate to this, or other circular shapes.
[0037]
[3] The grindstone 4 is inserted into each groove 3 from the open side and temporarily fixed so that the arrangement (positional relationship) of the grindstone 4 satisfies the above-described conditions.
[0038]
[4] Each grindstone 4 is fixed to the grindstone base 2 by a method such as bonding with an adhesive, brazing, plating (for example, electroless Ni plating), press-fitting, shrinking, sintering (especially plasma sintering). .
[0039]
[5] The tip surface and outer peripheral surface (side surface) of the grinding tool 1 are trued by a known method to form a sharp edge. This edge enables fine and precise processing, particularly groove processing and curved surface processing, on the workpiece.
[0040]
The grinding tool 1 of the present invention has less wear and chipping of the edge and is excellent in durability. Therefore, not only relatively soft materials such as copper, aluminum, electroless Ni plating and resin, but also relatively hard materials such as optical glass, ceramics, steel materials, stainless steel, cemented carbide, titanium or titanium alloys are used. It can also be processed.
[0041]
Moreover, the grinding tool 1 of the present invention has a smaller processing resistance than the grinding tool 10 because the exposed portion 42 of the grinding tool 4 is small and the contact length with the workpiece becomes very short. As a result, generation of vibration associated with grinding is suppressed, and brittle materials represented by ceramics can be processed without causing cracks. That is, the range of types, compositions, and characteristics of workpieces is expanded.
[0042]
The term “grinding” in the grinding tool of the present invention is used in a broad sense including not only “grinding” in a narrow sense used in mechanical engineering but also other examples such as “cutting” and “polishing”. It is what
[0043]
The grinding tool of the present invention has been described with respect to the illustrated embodiment. However, the present invention is not limited to this example. For example, the cross-sectional shape of the grindstone 4 is a polygon other than a square or any other shape. Things are possible.
[0044]
Moreover, the arrangement | positioning space | interval and the installation number of the grindstone 4 with respect to the grindstone base material 20 are not specifically limited.
[0045]
Further, the grindstone base material 20 is not limited to a columnar shape, and may be any rotary body shape such as a cylindrical shape (hollow), a solid or hollow truncated cone shape, and the like.
[0046]
Further, the constituent materials of the grindstone base 20 and the grindstone 4 may be other than those described above.
[0047]
【The invention's effect】
As described above, according to the grinding tool of the present invention, it is possible to prevent or suppress the falling of the grindstone.
[0048]
In addition, since it is excellent in durability and can suppress the occurrence of vibration due to a decrease in processing resistance, it is possible to process relatively hard materials and brittle materials, thereby expanding the range of materials to be processed.
[0049]
Further, it is preferably applied to groove processing for a diffractive lens type, diffraction grating type, diffraction grating itself, etc., and curved surface processing such as spherical surface and aspherical surface, and the processing accuracy is high.
[0050]
In addition, the grinding tool of the present invention is easy to manufacture because it is not necessary to take special measures to prevent the grinding stone from falling off.
[Brief description of the drawings]
FIG. 1 is a top view showing an embodiment of a grinding tool of the present invention.
FIG. 2 is a cross-sectional view taken along line AA in FIG.
FIG. 3 is a top view showing a configuration of a grinding tool of a comparative example.
FIG. 4 is a diagram showing the production of a diffractive lens mold by conventional cutting.
FIG. 5 is a diagram showing the production of a diffraction grating mold by conventional burnishing.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Grinding tool 2 Grinding wheel base material 3 Groove 4 Grinding stone 41 Embedded part 42 Exposed part 43, 44 Diagonal 5 Outer peripheral surface 6 Center axis 60 Axis 50 Base material 51 Single crystal diamond bite 52 Base material 53 Molding diamond tool 10 Grinding tool 20 Grinding wheel Base material 30 Groove 40 Grinding wheel

Claims (4)

A grinding tool provided with a grindstone base material in a rotating body, and a plurality of grindstones that are disposed over the entire outer periphery of the tip portion of the grindstone base material, and whose cross section is a square columnar diamond,
As for the said grindstone, one diagonal in a cross section crosses the outer peripheral surface of the said grindstone base material, and has faced the radial direction of the said grindstone base material, and another one diagonal is inside the outer peripheral surface of the said grindstone base material. A grinding tool characterized by being fixed to be positioned. A part of the grindstone is exposed to the outside of the outer peripheral surface of the grindstone base material, and the rest is embedded in the grindstone base material. The maximum circumferential width of the grindstone embedding portion is L ₁ , when the circumferential direction of the maximum width of the exposed portion of the grinding wheel was L _2, satisfies L ₁ / L ₂ ≧ 1.2 the relationship,
The grinding tool according to claim 1, wherein the grinding wheel base is rotated and the workpiece is ground by an edge formed on an exposed portion of the grinding wheel. A part of the grindstone is exposed to the outside of the outer peripheral surface of the grindstone base material, and the rest is embedded in the grindstone base material. The maximum circumferential width of the grindstone embedding portion is L ₁ , when the circumferential direction of the maximum width of the exposed portion of the grinding wheel was L _2, satisfies _{12 ≧ L 1 / L 2 ≧} 1.4 the relationship,
The grinding tool according to claim 1, wherein the grinding wheel base is rotated and the workpiece is ground by an edge formed on an exposed portion of the grinding wheel. The grinding wheel, so that its longitudinal direction is parallel to the central axis of the grindstone base and claims 1 are arranged at substantially equal intervals along the circumferential direction of the outer peripheral surface of the grinding wheel substrate 3 A grinding tool according to any one of the above.

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