JPH09254040A - Grinding wheel and lens grinding wheel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enchance the shape accuracy of an abrasive particle layer surface and reduce wearing deformation through grinding work so as to perform work of an axial symmetry non-spherical lens or the like in a high productivity. SOLUTION: A ground workpiece 9 or lens or the like is mounted in a prescribed position of a grinder. On the other hand, based on a ridge shape partly to a peripheral edge part of the workpiece 9 from a symmetrical axis 10, in the ride shape of a section including the symmetrical axis 10 of desired shape of the workpiece 9, a sectional shape corresponding to this partly ridge shape is formed between an axial center 11 and the peipheral edge part in an axially symmetrical abrasive particle layer surface 6, a grinding wheel 1 provided therewith is mounted in the grinder. The abrasive particle layer surface 6 of this grinding wheel 1 has a shape corresponding to the peripheral edge part of desired shape of the workpiece 9 in a side of the axial center, and has a corresponding shape in a side of the symmetrical axis 10 of the desired shape of the workpiece 9 in the peripheral edge part of the abrasive particle layer surface 6. While the workpiece 9 and the abrasive particle layer surface 6 of the grinding wheel 1 are brought into contact, by mutually rotating, a surface shape or an abrasive particle layer 5 is transcribed to the workpiece 9.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a grindstone used for grinding various objects to be ground, and particularly to a grindstone suitable for high-precision grinding of axisymmetric aspherical lenses and lens grinding. It concerns a whetstone.

[0002]

2. Description of the Related Art Generally, in the case of manufacturing a lens by a grinding and polishing method, a processing method is adopted for a spherical lens or a plane lens by sliding the object to be ground and a grindstone together. As the grindstone used for grinding the spherical lens, as shown in FIG. 3, a resin bond grindstone, a metal bond grindstone, a vitrified bond grindstone having a structure in which an abrasive grain layer 32 is attached to a substrate 31, or the grindstone shown in FIG. As described above, there is an electrodeposition grindstone in which abrasive grains are fixed to the surface of the base body 41 by electrodeposition to form the abrasive grain layer 42.

However, in grinding an axially symmetric aspherical lens, the abradable object and the grindstone are displaced from each other by the processing method by co-sliding which is performed in the case of a spherical lens. Therefore, it was processed by using an aspherical grinder with a highly accurate numerical control system. An example of this processing method is as shown in FIG. 2, in which a straight type grindstone 22 having an arc-shaped cross section of the surface of an abrasive grain layer is attached to a rotary shaft 21 of an aspherical grinder, and the object to be ground 9 is fed in a horizontal direction while being rotated. On the other hand, grinding is performed by controlling the vertical grindstone 22 to be driven up and down at a predetermined speed while rotating. This grinding is performed in several steps while changing the grain size of the straight type grindstone 22 from coarse to fine, to create an aspherical surface. After that, the surface of the object to be ground 9 is finished and polished by polishing with an elastic polishing material.

The types of grindstones used for the straight type grindstone 22 include the above-mentioned resin bond grindstone, metal bond grindstone, vitrified bond grindstone, and electrodeposition grindstone. Especially, in the manufacture of aspherical lenses, It was important to make the finishing accuracy in grinding process highly accurate in order to reduce the burden of polishing in the next process and the change in the shape of the lens due to polishing, and it was important to select the grindstone suitable for the purpose .

[0005]

However, among the above-mentioned grindstones, in the resin-bonded grindstone, the metal-bonded grindstone, and the vitrified bond grindstone, the hardness of the bond material of the abrasive grain layer 32 is low, so that the used portion is worn out. It was easily deformed, and it was necessary to stop the production work and frequently modify the shape of the grindstone surface. In particular, in the straight type grindstone 22 used for grinding an aspherical lens, as shown in FIG. 2, since the object 9 is ground by point contact, heavy grinding is not possible, and therefore the processing time is also required. It becomes longer, and further, it is necessary to correct the distance to the object to be ground 9 and the correction of the drive each time in response to the abrasion of the surface of the grindstone, which causes a problem of low productivity.

On the other hand, the electrodeposition grindstone has a characteristic of being less likely to be worn and deformed as compared with the bond type grindstone such as the resin bond grindstone, but in the manufacture thereof, the abrasive grain layer 42 is uniformly distributed along the surface shape of the substrate 41. Since it has the property of not being formed, it is generally attempted to fix one layer of abrasive grains to make the abrasive grain layer uniform, but in reality, it was not always formed in the desired shape. Therefore, before using for grinding, using a correction plate made of cast iron or the like having a shape facing the electrodeposition grindstone and sand, many of which require the shape correction work of the surface of the grindstone, and have a desired shape. It was very difficult to get a whetstone. Further, since the abrasive grain layer is a single layer, the processing ability until the abrasive grain layer is worn out is small, and continuous grinding of a large number of lenses has been difficult.

A conventional grindstone having a spherical shape as shown in FIGS. 3 and 4 is changed to an axisymmetric aspherical shape to form a grindstone, and the grindstone having the axisymmetric aspherical shape is used as the grindstone. Even if you try to grind an aspherical lens by rotating around the axis of symmetry, the object to be ground and the grindstone will be in surface contact over the entire surface of the aspherical surface, so the surface of the grindstone will contact the object evenly. It is very difficult to make it, and it is not possible to create an aspherical surface.

The present invention has been made in view of the conventional problems as described above, and obtains a grindstone for grinding which has a high shape accuracy on the surface of the grindstone, has little wear deformation during grinding, and wears off the abrasive grain layer. It is an object of the present invention to provide a grinding wheel capable of continuously grinding a large number of objects to be ground such as lenses having a high processing ability and a high finishing accuracy. Further, it is an object of the present invention to provide a grindstone for lens grinding which can process an axisymmetric aspherical lens with high productivity.

[0009]

In order to achieve the above object, a first invention (claim 1) is an intermediate layer formed on the surface of a substrate with a substance which serves as a catalyst for promoting a reaction by electroless plating. And an abrasive grain layer formed of a composite film containing abrasive grains formed by electroless plating.

Since the abrasive grain layer is a composite film of metal and abrasive grains formed by electroless plating, the abrasive grain layer can be formed with a uniform thickness irrespective of the shape of the substrate surface, and the shape precision of the surface of the grindstone is good. Further, the abrasive layer formed by electroless plating is less likely to be deformed by abrasion. The electroless plating includes electroless nickel plating and electroless copper plating, but electroless nickel plating is preferable in terms of strength. In addition to diamond, the types of abrasive grains are CBN (Cubic Boron Nitr) depending on the application.
ide) or the like may be used. The material to be ground includes glass, plastic, metal, ceramics,
Examples include stone materials.

The abrasive grain layer of the composite coating is preferably formed in a plurality of layers. Here, multiple layers means two or more layers,
A plurality of abrasive grain layers, for example, three abrasive grain layers, means that there are approximately three abrasive grains in the thickness direction of the abrasive grain layer.
When the abrasive layer is formed in multiple layers, even if the abrasive particles on the surface of the abrasive layer wear or fall off, the abrasive particles of the inner layer will self-generate one after another, so it is possible to continuously grind a large number of objects to be ground. It has a large processing ability until the abrasive grain layer is worn out.

Examples of the material of the substrate include brass, steel, iron alloys such as stainless steel, and aluminum alloys. Of these, brass has a finer surface roughness than iron alloys and aluminum alloys in machine processing for forming a base body, and high shape accuracy can be obtained. Therefore, it is preferable to use a brass material for the base body. By forming an abrasive grain layer on a brass substrate by an electroless plating method having a uniform deposition property, a grindstone having high surface shape accuracy can be manufactured. Since the surface shape accuracy is high, it is suitable for a grindstone of a general shape facing the object to be ground, and it is possible to grind not only spherical lenses but also axisymmetric aspherical lenses.

The intermediate layer has a catalytic action such as changing the metal deposition rate in electroless plating, and is made of palladium, platinum, zinc or the like, and is selected according to the material of the substrate and the use of the grindstone. For example, an intermediate layer of palladium or platinum is formed on a brass or stainless steel substrate, and an intermediate layer of zinc is formed on an aluminum alloy substrate as a pretreatment for electroless plating on the substrate surface.

For brass substrates, a palladium interlayer is most suitable. The palladium intermediate layer serves as a catalyst for promoting the precipitation of nickel during electroless plating on a brass substrate, but since the film thickness is very thin, 0.01 μm or less, the shape of the substrate is It does not damage and has good adhesion to nickel plating. Since the shape accuracy of the substrate can be maintained even after applying the palladium layer, a grindstone with high shape accuracy can be obtained that can also grind an axisymmetric aspherical lens.

The palladium layer is easily formed by the displacement treatment by only immersing the substrate in a one-liquid palladium solution (for example, palladium chloride dissolved in hydrochloric acid). This solution can be easily made by hand, and many are commercially available, and the solution itself is stable. Further, the electroless plating can be carried out in a continuous process only by washing with water after applying the palladium layer, so that nickel deposition can be efficiently promoted. Noble metals other than palladium, such as platinum, can also be used as a catalyst to obtain a platinum layer from a one-component platinum solution, but since it is rarely marketed as a solution, workability is also high. Palladium is suitable.

As another method of applying a metal such as palladium as a catalyst to the surface of the substrate in order to promote the deposition of electroless plating on the brass substrate, a method of applying by vapor phase treatment such as vapor deposition or ion plating, or There is a method of applying it by electrolytic plating, but in both cases it is not possible to efficiently promote the precipitation of metal such as nickel because the processing takes time or the process is different, or the film thickness of the applied metal layer is uniform. However, it is not suitable because the shape accuracy is impaired.

Further, grooves may be formed on the surface of the abrasive grain layer to facilitate the escape of lens powder, grinding liquid, etc. generated during the grinding process to the outside. If a groove is provided in advance on the surface of the base by machining and the abrasive grain layer is formed on this base by electroless plating, the groove can be formed on the surface of the abrasive grain layer without impairing the shape accuracy. The groove is cut, for example, in a radial shape or a spiral shape according to the surface shape of the substrate.

According to a second aspect of the present invention (claim 8), the desired lens shape is axially symmetric, and the symmetric axis to the peripheral portion of the lens with respect to the ridge line shape of the cross section including the symmetric axis of the shape. Based on the partial ridge line shape in the part of, the cross-sectional shape corresponding to the partial ridge line shape is formed between the axial center and the peripheral portion, the abrasive grain layer surface having a shape axially symmetrical to the axial center Having a shape of the abrasive grain layer surface, a shape corresponding to the peripheral portion of the shape of the desired lens is provided in the vicinity of the axis of the abrasive grain layer surface, and further on the peripheral portion of the abrasive grain layer surface. The grinding wheel for lens grinding is provided with a shape corresponding to the vicinity of the axis of symmetry of the desired lens shape.

A lens which is an object to be ground is attached to a predetermined position of a grinding machine. Then, based on the partial ridgeline shape in the portion from the symmetry axis in the ridgeline shape of the cross section including the symmetry axis of the lens to the peripheral edge portion of the lens, the sectional shape corresponding to the partial ridgeline shape is divided from the axial center to the peripheral edge. A grindstone having a surface of an abrasive grain layer formed between the parts is attached to a grinding device. The surface of the abrasive grain layer of this grinding wheel has an axisymmetric shape, and the shape of the surface of the abrasive grain layer is in the vicinity of the axis of the surface of the abrasive grain layer in the peripheral portion of the shape of the desired lens. A corresponding shape is provided, and further, a shape corresponding to the vicinity of the symmetry axis of the desired lens shape is provided on the peripheral portion of the surface of the abrasive grain layer. In this way, while contacting the object to be ground and the surface of the abrasive grain layer,
By rotating each other, the surface shape of the abrasive grain layer can be transferred to the object to be ground. Further, by using such a grindstone, since the part that comes into contact with the object to be ground is only the part that abuts the ridge line of the grindstone cross section, actually the entire grindstone does not contact the object to be ground, Only part of the object to be ground contacts.

The above-mentioned abrasive grain layer has an intermediate layer formed on the surface of a substrate by a substance which serves as a catalyst for promoting a reaction by electroless plating, and an abrasive layer formed by electroless plating on the intermediate layer. It is preferable that it is formed of a composite film containing particles. When the abrasive grain layer is formed in this manner, a grindstone having high shape accuracy can be obtained as in the first invention, and it is suitable for grinding an axisymmetric aspherical lens.

[0021]

1 is a longitudinal sectional view showing an embodiment of a lens grinding wheel according to the present invention. The lens grinding wheel of this embodiment is a grinding wheel for grinding a convex aspherical lens. is there.

The substrate 2 of the grindstone 1 for lens grinding has a mushroom shape as a whole, and an abrasive grain layer 5 is formed on the substrate surface 3 on the tip end side of the umbrella shape or mountain shape, and at the same time, it has an axial shape. The base body 4 is adapted to be attached to a grindstone mounting shaft (not shown) of a grinding device. As the material of the base 2, brass is used because the shape can be processed with high precision.

The substrate surface 3 has a curved surface corresponding to the finished shape of the object to be ground 9 to be processed into an axisymmetric aspherical lens. That is, when the desired lens shape is an axisymmetric aspherical surface, the cross-sectional shape of the abrasive grain layer surface 6 has a shape corresponding to the cross-sectional shape of the object 9 to be ground including the axis of symmetry 10.
The shape of the abrasive grain layer surface 6 corresponding to the shape of the peripheral portion in the desired lens shape is formed in the portion of the abrasive grain layer surface 6 that is in contact with the workpiece 9 near the end face portion 12. Further, the shape of the abrasive grain layer surface 6 corresponding to the shape in the vicinity of the symmetry axis 10 in the desired lens shape is formed in the peripheral edge portion of the abrasive grain layer surface 6. Then, the grindstone 1 is brought into contact with the object 9 to be ground in a state where the symmetry axis 10 of the object 9 to be ground and the axis 11 of the grindstone 1 are parallel to each other. At this time, the abrasive grain layer surface 6 at the peripheral edge of the grindstone 1 comes into contact with a portion near the axis of symmetry 10 of the object to be ground 9, and the end surface portion 12 of the grindstone 1 comes into contact with the peripheral edge of the object to be ground 9.
Install so that the vicinity of is in contact. In this way, the object to be ground 9 and the grindstone 1 are brought into contact with each other for grinding. The flat end face portion 12 on the tip end side of the base body 2 is provided for relief in machining.

The intermediate layer 7 between the abrasive grain layer 5 and the substrate surface 3 is a palladium layer for efficiently promoting the deposition of electroless plating. The thickness of the palladium intermediate layer 7 is If it is too thick, the adhesion of the plating will deteriorate, so 0.0
It is set to 1 μm or less.

The abrasive grain layer 5 is a composite coating layer of nickel and diamond, and is formed in a plurality of layers by electroless plating. The thickness of the abrasive grain layer 5 varies depending on the particle size of the abrasive grains 8 contained, but is generally in the range of 0.01 mm to 0.1 mm. The grain size of the abrasive grains 8 contained in the abrasive grain layer 5 may be any grain size of existing grains, and may be selected according to the purpose of grinding. It should be noted that, if necessary, the abrasive grain layer surface 6 is radially formed with a groove or the like for discharging the lens powder generated during the grinding process or the removed abrasive grains 8 to the outside of the process.

Next, the manufacturing process of the grindstone 1 for lens grinding will be described.

First, the material for the base 2 is processed with a diamond tool or the like to produce the base 2 having the base surface 3 having a shape opposite to the finished shape of the work 9 to be processed. Next, after washing the substrate 2 as a pretreatment before electroless plating, the substrate 2 is put in a palladium solution to form a palladium layer on the substrate surface 3. This is the intermediate layer 7. The palladium intermediate layer 7 is formed on the substrate surface 3 in an extremely thin film or island shape.

Next, the substrate 2 having the intermediate layer 7 formed on the surface 3 of the substrate is placed in an electroless plating solution containing nickel solution as a main component and predetermined diamond particles dispersed therein, and the electroless plating solution is stirred. While plating. As a result, a composite coating in which the diamond abrasive grains 8 are uniformly incorporated in nickel can be formed uniformly along the shape of the substrate surface 3. That is, this composite film becomes the abrasive grain layer 5. After that, by using a dummy lens having the same shape as the object to be ground, the abrasive grain layer surface 6 is dressed and the cutting edges are aligned, whereby the lens grinding wheel 1 is completed.

As described above, the abrasive grain layer 5 of nickel and diamond formed by the electroless plating method is formed on the substrate 2 having the substrate surface 3 having a shape opposite to the finished shape of the lens to be processed.
By forming the, the lens grinding wheel 1 having the abrasive grain layer surface 6 having a shape opposite to the finished shape of the workpiece 9 to be processed can be manufactured with high shape accuracy.

When the object to be ground 9 is ground by the grindstone 1, as shown in FIG. 1, the grinding device is set so that the axis of symmetry 10 of the object to be ground 9 and the axis 11 of the wheel 1 are parallel to each other. Each is positioned and attached at a predetermined position, and the grindstone 1 and the object to be ground 9 are rotated and the grindstone 1 is fed in the axial direction. On the surface 6 of the abrasive grain layer (or on the working surface of the grindstone), a portion of one half of the object 9 to be ground corresponding to the above-mentioned ridge line in cross section contacts the object 9 to be ground, and the object 9 to be ground is ground. By contacting in this manner and grinding the grindstone 1 and the object to be ground 9 while rotating each at an arbitrary angular velocity, the shape of the abrasive grain layer surface 6 is transferred to the object to be ground 9, and the object to be ground 9 An axisymmetric aspherical surface is created.

In the above embodiment, the whetstone for grinding a convex aspherical lens has been described, but the present invention is not limited to this, and a whetstone for grinding a concave aspherical lens or for grinding a spherical lens or a plane lens is also applicable. Of course it is possible.

[0032]

As described above, in the first invention (Claim 1), the abrasive grain layer formed on the surface of the substrate through the intermediate layer is a composite coating of metal and abrasive grains by electroless plating.
The abrasive grain layer can be formed with a uniform thickness regardless of the shape of the substrate surface, and the shape precision of the abrasive grain layer surface is good. Therefore, the surface preparation work of the grindstone before using the grindstone for the grinding process only requires a simple surface preparation that also serves as dressing. Furthermore, the abrasive grain layer formed by electroless plating has less wear than metal-bonded grindstones and resin-bonded grindstones, and wears evenly, so there is no need to modify the shape of the grindstone, improving productivity. be able to.

In the above, if the abrasive grain layer is a plurality of layers,
Even if the abrasive grains on the surface of the abrasive grain layer are worn or fallen off, the abrasive grains of the inner layer are self-generated one after another, so that a large number of objects to be ground can be continuously ground. When the base material is brass, the brass has a finer surface roughness than the iron alloy and the aluminum alloy in the machining for forming the base, so that the shape accuracy can be improved. Further, when the intermediate layer is made of palladium or platinum, it can be easily and extremely thinly formed on the surface of the substrate by a substitution treatment or the like, so that the shape accuracy of the substrate is not impaired. Further, if grooves are provided on the surface of the abrasive grain layer, chips such as lens powder and grinding liquid generated during the grinding process can easily escape to the outside.

In the second invention (claim 8), the desired lens shape is axisymmetric, and with respect to the ridge line shape of the cross section including the axis of symmetry of the shape, from the axis of symmetry to the peripheral portion of the lens. Based on the partial ridge line shape in the part of, the cross-sectional shape corresponding to the partial ridge line shape is formed between the axial center and the peripheral portion, the abrasive grain layer surface having a shape axially symmetrical to the axial center Having a shape of the abrasive grain layer surface, a shape corresponding to the peripheral portion of the shape of the desired lens is provided in the vicinity of the axis of the abrasive grain layer surface, and further on the peripheral portion of the abrasive grain layer surface. A shape corresponding to the vicinity of the symmetry axis of the desired lens shape is provided. The surface shape of the abrasive grain layer can be transferred to the object to be ground by rotating each other while bringing the surface of the abrasive grain layer of the grindstone for lens grinding and the lens into contact with each other. In such grinding, the portion that comes into contact with the lens is only the portion that abuts the ridgeline of the grindstone cross section, and only part of the grindstone and part of the lens make contact and grinding is performed. Therefore, not only the spherical lens but also the axisymmetric aspherical lens can be quickly ground. Furthermore, not the entire ridge line shape of the lens cross section, but the partial ridge line shape from the axis of symmetry to the peripheral edge is the shape of the surface of the abrasive grain layer obtained when the lens is rotated around the axis of the grindstone. The machining of the surface of the grain layer can be performed easily and quickly.

Further, in the above, the abrasive grain layer has an abrasive grain formed by electroless plating on the surface of the substrate, and an intermediate layer formed of a substance serving as a catalyst for promoting the reaction by electroless plating. When the abrasive grain layer of the composite film containing the same is used, a grindstone having a high shape accuracy can be obtained, which is suitable for grinding an axisymmetric aspherical lens.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of a grindstone for lens grinding according to the present invention.

FIG. 2 is a vertical cross-sectional view showing a grindstone for processing a conventional axially symmetric aspherical lens and a processing method thereof.

FIG. 3 is a longitudinal sectional view showing a bond type grindstone such as a conventional resin bond grindstone for spherical lens grinding.

FIG. 4 is a vertical cross-sectional view showing a conventional electrodeposition grindstone for spherical lens grinding.

[Explanation of symbols]

 1 Grindstone for Lens Grinding 2 Base 3 Base Surface 4 Base Base 5 Abrasive Grain Layer 6 Abrasive Grain Layer Surface 7 Intermediate Layer 8 Abrasive Grain 9 Grinding Object 10 Symmetrical Axis 11 Shaft Center 12 End Face

Claims (15)

[Claims] 1. An intermediate layer formed on a surface of a substrate with a substance serving as a catalyst for promoting a reaction by electroless plating, and an abrasive grain layer formed with a composite coating containing abrasive grains formed by electroless plating. A grindstone for grinding, which comprises: 2. The grindstone for grinding according to claim 1, wherein the abrasive grain layer is formed in a plurality of layers. 3. The grindstone for grinding according to claim 1, wherein the base is made of brass. 4. The grinding wheel according to claim 1, wherein the intermediate layer is made of platinum or palladium. 5. The grinding wheel according to claim 1, wherein a groove is formed on the surface of the abrasive grain layer. 6. The grinding wheel according to claim 5, wherein the grooves formed on the surface of the abrasive grain layer are formed in a radial or spiral shape. 7. The grinding wheel according to claim 1, wherein the substrate has a general surface shape that is opposed to the finished shape of the object to be ground. 8. A desired lens shape is axially symmetric, and based on a partial ridgeline shape in a portion from the symmetric axis to the peripheral edge portion of the lens with respect to the ridgeline shape of a cross section including the symmetry axis of the shape. In, the cross-sectional shape corresponding to the partial ridge shape has an abrasive grain layer surface having a shape axially symmetrical with respect to the axis formed between the axial center and the peripheral portion, the abrasive grain surface of the The shape is provided with a shape corresponding to the peripheral portion of the shape of the desired lens in the vicinity of the axis of the surface of the abrasive grain layer, and further on the peripheral portion of the surface of the abrasive grain layer of the symmetry axis of the shape of the desired lens. A grindstone for lens grinding, which is provided with a shape corresponding to the vicinity. 9. The desired lens shape is an axially symmetric aspherical shape, and when the symmetry axis of the desired lens shape and the axial center of the abrasive grain layer surface are parallel, A cross-sectional shape corresponding to the partial ridgeline shape of the lens is formed between the axis of the abrasive grain layer surface and the peripheral portion, and the abrasive grain layer surface is relative to the axis of the shape of the abrasive grain layer surface. The grinding wheel for lens grinding according to claim 8, wherein the grinding wheel has an axially symmetrical shape. 10. The abrasive grain layer has an intermediate layer formed on a surface of a substrate, the intermediate layer being made of a substance that serves as a catalyst for promoting a reaction by electroless plating, and formed on the intermediate layer by electroless plating. The grindstone for lens grinding according to claim 8 or 9, wherein the grindstone is formed of a composite film containing abrasive grains. 11. The grindstone for lens grinding according to claim 10, wherein the abrasive grain layer of the composite film is formed in a plurality of layers. 12. The grinding wheel for lens grinding according to claim 10, wherein the base is made of brass. 13. The grinding wheel for lens grinding according to claim 10, wherein the intermediate layer is made of platinum or palladium. 14. The grindstone for lens grinding according to claim 8, wherein a groove is formed on the surface of the abrasive grain layer. 15. The groove formed on the surface of the abrasive grain layer,
The grindstone for lens grinding according to claim 14, wherein the grindstone is formed in a radial shape or a spiral shape.