JPH05185372A - Grinding method and grinding machine - Google Patents

Abstract

(57) [Summary] [Objective] To provide a processing method (including truing) for grinding a brittle material to the order of nanometer and a grinding machine therefor. [Structure] In a grinder for grinding on the order of nanometers, one high-precision axis is used as a truing wheel axis and a work rotation axis, and the work is attached to this axis without removing the truing wheel from the axis. To process. [Effect] Truing with the above structure of the grinder,
By processing the work, it is possible to prevent the truing grindstone from swinging when the truing device and the truing grindstone are attached / detached. Therefore, the truing of the grinding grindstone can be made highly accurate. It can be processed with processing accuracy.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a grinding method and a grinding machine for brittle materials.

[0002]

2. Description of the Related Art In ultra-precision grinding of brittle materials, which has been attracting attention in recent years, shape accuracy and surface roughness on the order of nanometers are targeted, and for this purpose, diamond grinding wheels are highly accurate on a submicro-order basis. Must be trued to. In order to perform this truing with high accuracy, it is preferable to rotate the truing grindstone on the machine of the grinding machine to perform truing. The conventional on-machine truing is "Research on truing of vitrified diamond grinding wheel" (Journal of Precision Engineering Vol.52).
As described in No. 2 (1986-2), P91-96), it is common to attach a truing device to a grinding machine for truing. For this reason, there is a work of attaching and detaching the truing device, and due to this work, the swing of the truing grindstone occurs on the order of several tens of μm. For this reason, it is insufficient as truing for the purpose of obtaining processing accuracy on the order of nanometers.

[0003]

In grinding, it is the truing accuracy of the diamond grinding wheel that has the greatest effect on the surface roughness. Specifically, it is possible to improve the processed surface roughness by reducing the rotational runout of the diamond grinding wheel and making the cutting edge heights of the abrasive grains uniform. In truing using the above-mentioned truing device, there is a work of attaching and detaching the truing device and a work of attaching and detaching the truing grindstone, and with these works, the wobbling of the truing grindstone and the inclination to the diamond grinding whetstone occur.
When these occur, only a part of the truing grindstone participates in the truing, and the diamond grinding grindstone cannot be trued with high accuracy. Therefore, it is unsuitable for truing a diamond grindstone for the purpose of processing accuracy on the order of nanometers.

[0004]

[Means for Solving the Problem] In order to obtain a processing accuracy on the order of nanometers by grinding, a diamond grinding wheel for truing is attached to a highly accurate truing device (truing shaft), and a diamond grinding wheel is processed by this grinding wheel. By doing so, it is necessary to reduce the rotational run-out of the diamond grinding wheel from the conventional micron order to the submicron order and to make the abrasive grain cutting edge heights uniform on the submicron order. As a grinding machine for this purpose, a spindle for attaching a diamond grinding wheel to process a work and a truing device (truing shaft) for attaching a truing diamond wheel are necessary. Here, in consideration of the swing of the truing grindstone, it is desirable that the truing device (truing shaft) is provided in the grinder. Further, a surface rotating machine, a cylindrical grinding machine, and the like require a work rotating shaft, and in order to perform the above-mentioned truing with these grinding machines, there are three grinding wheel shafts, a truing grinding wheel shaft, and a work rotating shaft. A shaft is needed. Since each shaft requires a highly accurate shaft, the cost of manufacturing the shaft is high, and the size of the shaft is large, so that the grinding machine itself becomes large.

In order to solve the above problems, it was devised that a work is attached to a truing grindstone shaft and machined so that one shaft is used as a truing grindstone shaft and a work rotating shaft. Further, in this case, since one shaft is shared, a truing grindstone must be attached during truing, and a work must be attached during work processing. For this reason, the truing grindstone must be removed after the truing is completed, and when the truing grindstone is performed again, the truing grindstone is shaken due to an installation error of the truing grindstone, which lowers the truing accuracy. Therefore, a working method has been invented in which the work is attached to the truing grindstone shaft without removing the truing grindstone and the work is machined.

[0006]

In the above grinding method, the truing device and the truing grindstone, which have been problems in the conventional truing method, can be omitted. Therefore, the wobbling of the truing grindstone on the order of several tens of μm and the diamond grinding wheel caused by these truing operations can be omitted. It is possible to prevent the inclination against. By preventing these, the number of abrasive grains involved in the truing of the truing grindstone increases. By increasing the number of abrasive grains, it is possible to process (truing) the grinding stone with many diamond abrasive grains (cutting edges). Therefore, the processing amount per one diamond abrasive grain (cutting edge) becomes small, and as a result, the diamond grinding wheel can be trued with high accuracy,
Processing on the order of nanometers is possible.

[0007]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is an external view of surface grinding, and FIG. 2 is an enlarged sectional view of a truing grindstone shaft truing grindstone mounting portion. Reference numeral 1 denotes a grinding wheel shaft, which uses a hydrostatic air bearing as a bearing to obtain high rotation accuracy (rotation accuracy 10 nm). A cup-shaped diamond grinding wheel 2 (hereinafter referred to as a diamond grinding wheel), which is a tool for processing a workpiece, is attached to the grinding wheel shaft 1. Further, the truing grindstone shaft 6 is arranged so as to face the grinding grindstone shaft 1. This truing wheel spindle 6 is also the grinding wheel spindle 1
By using a hydrostatic air bearing as a bearing in the same manner as above, it has high rotation accuracy. Truing wheel axis 6
A cup-shaped diamond whetstone 5 for truing (hereinafter referred to as a truing whetstone), which is a tool for processing the diamond grinding whetstone 2 at the time of truing, is attached to this. Further, when the work is ground after the truing is finished, the work mounting base 4 holding the work 3 on the truing grindstone shaft 6 is mounted inside the truing grindstone 5. At this time, the surface of the workpiece mounting table 4 on which the workpiece is mounted is configured to protrude from the processed surface of the truing grindstone 5. With such a structure, the surface of the grindstone to be processed does not come into contact with the surface of the truing grindstone during processing of the workpiece. Therefore, the work can be attached to the truing grindstone shaft 6 without removing the truing grindstone 5, and as a result, the swinging of the truing grindstone 5 that occurs when the truing grindstone 5 is attached or detached can be prevented. The movement of the grinder includes the rotation of the grinding wheel shaft 1 and the truing wheel shaft 6, the movement of the grinding wheel shaft 1 in the axial direction of the grinding wheel shaft 1 (cutting), and the movement of the truing wheel shaft 6 into the grinding wheel. It is possible to move (feed) in the direction perpendicular to the axial direction of the shaft 1.

Next, an example in which a brittle material is actually processed by the processing method of the present invention will be described.

Before starting truing, the diamond grinding wheel 2 is attached to the grinding wheel shaft 1. The grain size of the diamond grinding wheel 2 was # 1500, and the bonded one was resinoid bond. Then, the truing diamond grindstone 5 is attached to the truing grindstone shaft 6. For the truing diamond grindstone 5, a bonded metal bond having a strong abrasive grain holding force was used, and # 200 having a relatively coarse grain size was used. After that, the truing is performed. At the time of truing, the work 3 and the work mount 4 are
Is removed. In the truing, both grindstones were brought into contact with each other while rotating, the grinding grindstone shaft 1 was cut in a small amount in the direction of the truing grindstone shaft 6, and the grinding grindstone 2 was trued (processed). The truing conditions are shown below.

Grinding wheel: SD1500N100B Truing wheel: SD200Q125M Grinding wheel rotation speed: 300 r / min Truing grinding wheel rotation speed: 2000 r / min Cutting amount per time: 1.0 μm Initial truing It was possible to reduce the rotational run-out of the diamond grinding wheel 2 from 8 μm to 0.5 μm. This is because it is possible to prevent the truing grindstone from swinging due to the attachment and detachment of the truing grindstone 5. Next, the work 3 is attached to the truing shaft 6 via the work mount 4 without removing the truing grindstone 5. For the work 3, BK7 which is a general optical glass is used.

Next, the processing procedure will be described. First, the grinding wheel shaft 1 is moved to a position where the processed surface of the diamond grinding wheel 2 and the processed surface of the work 3 come into contact with each other. Then, the position of the first contact is set as the origin of the cut. Then, the truing grindstone shaft 6 reaches a position where the work 3 and the grinding grindstone 2 do not contact each other.
To move. The position of the truing grindstone shaft 6 at that time is set as the feed origin. This is the preparation before processing. The processing was performed by cutting the diamond grinding wheel shaft 1 by a certain amount from the origin of cutting, and feeding the truing wheel shaft 6 from the origin of feeding at a constant speed in the direction in which the workpiece 3 and the diamond grinding wheel 2 contact each other. The processing conditions are shown below.

Grinding wheel: SD1500N100B Work material: BK7 Grinding wheel shaft speed: 3000 r / min Truing wheel shaft speed: 350 r / min Feed rate: 10 mm / min Depth of cut: 2 μm or more As a result, optical glass BK7
Was able to be ground into a mirror surface with a surface roughness of 6 nm Rmax. FIG. 3 shows a sectional curve of the processed surface roughness measured by a stylus type surface roughness meter. This time, a surface similar to lapping was obtained by grinding, using a truing wheel spindle with high rotational accuracy, reducing the rotational run-out of the grinding wheel of the diamond grinding wheel to the submicron order, and increasing the cutting edge height. It was because I was able to arrange. In addition, the diamond grinding wheel 2 (rotary runout 8 μ
m), the optical glass BK7 was processed under the same processing conditions as described above.
Met. From this result, it can be seen that the present invention is effective as a method for grinding a brittle material to the nanometer order.

The cutting edge condition of the diamond grinding wheel 2 is
By machining the work 3, it is significantly changed. In order to maintain the processed surface roughness as described above, truing must be frequently performed. At this time, in the truing shaft structure of the present invention, since the work of attaching and detaching the truing grindstone can be omitted, the time required for this work can be shortened, and further, the wobbling of the truing grindstone can be prevented. From this, according to the present invention, highly accurate truing can be stably performed, and therefore, the grinding process of the nanometer order can be stably performed.

Although BK7, which is an optical glass, is used as the work in the above-mentioned embodiment, since the brittle material is not limited to glass, the results of processing single crystal ferrite and zirconia as general brittle materials other than glass are shown below. Shown in.
Both of them were processed under the same processing conditions as those of the above-described embodiment in which BK7 was processed. (Rotary run-out of diamond grinding wheel 0.5
μm) ・ Single crystal ferrite machined surface roughness 15nmRmax ・ Zirconia machined surface roughness 15nmRmax

[0016]

As described above, the present invention aims to obtain machining accuracy on the order of nanometers by grinding, and when performing truing for this purpose with high accuracy, the truing grindstone shaft and the work rotating shaft are commonly used. By using the same, the cost required for manufacturing the shaft can be reduced and the space for one shaft of the grinding machine can be saved. In addition, the work of attaching and detaching the truing device can be omitted, so that
It is possible to reduce the working time and prevent the truing grindstone from swinging when the truing device is attached. Further, by making the grinder a structure capable of processing the work without removing the truing grindstone, it is possible to prevent the truing grindstone from swinging when the truing grindstone is attached or detached. Therefore, by performing truing with the above-described device and processing the work, the work surface can be finished to have a processed surface roughness on the order of nanometers.

[Brief description of drawings]

FIG. 1 is an external view of surface grinding.

FIG. 2 is an enlarged sectional view of a truing shaft truing grindstone mounting portion.

FIG. 3 is a view showing a sectional curve of processing roughness measured by a stylus type surface roughness meter.

[Explanation of symbols]

 1 ... Grinding wheel axis 2 ... Diamond grinding wheel 3 ... Work 4 ... Work mount 5 ... Truing diamond wheel 6 ... Truing wheel axis

Claims (2)

[Claims] 1. At least two of a grinding wheel shaft and a work rotating shaft.
In a grinding machine having a shaft, a truing grindstone is attached to a work rotary shaft to perform truing, and then the work is mounted to the work rotary shaft without removing the truing grindstone for machining. 2. At least two of a grinding wheel shaft and a work rotating shaft.
In a grinding machine with a shaft, it is possible to perform truing by attaching a truing grindstone to the work rotating shaft, and to have a structure in which the work can be attached to the work rotating shaft without removing the truing grindstone and processed. Board.