JPH1110466A - Working method and device for high-accuracy very small hole - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the center of a tool and the center of rotation of a spindle of the device from being shifted from each other by providing such a structure as to form a working tool on a working machine, and conducting cutting work with the tool formed on the spindle for working. SOLUTION: In addition to a cutting part, a tool forming unit 5 having a spindle in common with the working part is installed on a working machine. In the tool forming unit, voltage is applied between a tool raw material and a fine electrode, and the positional relationship between the tool spindle and the fine electrode is changed by moving the turning angles of x, y, z and the spindle by NC device, and grooving and cutting edge working are performed for the tool raw material to obtain a desired tool shape. Subsequently, a work piece 2 is cut by the manufactured small-diameter tool 1. Further, according to the tool abrasion, the tool 1 is again moved to the tool forming unit 5 to correct the knife edge.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for processing a high-precision fine component, and more particularly to a component having a hole having a high aspect ratio.
And its processing method and manufacturing apparatus.

[0002]

2. Description of the Related Art There are mainly three conventional methods for processing fine holes. This is a method using etching, cutting, and electric discharge machining. The etching method is a method in which a resist film having a desired pattern is formed on a surface to be processed, and a workpiece is removed by physical or chemical action using the resist film as a mask. With this method, a very fine pattern of submicron can be formed.However, when processing a deep hole with a depth of several microns or more, the straightness of the hole is deteriorated because the side surface processing proceeds at the same time. It is difficult to process fine holes with an aspect ratio with high precision.

In cutting, as described in JP-B-61-10252, first, a tool mounted on a tool holder formed in advance on a main shaft of a processing machine is used by an operator or a tool of the processing machine. Install using an automatic exchange device. Thereafter, the tool is moved to a desired position, and the main shaft is rotated to process the workpiece. According to this method, a small-diameter tool for processing a fine component has a low rigidity, so that it is damaged at the time of mounting and transport. Further, during processing, the rotation center of the main shaft of the processing machine and the axis of the tool are displaced due to a mounting error of the tool or the tool holder, and the rotation is not stable, and the tool is easily damaged. In addition, it is difficult to machine a fine part with high accuracy due to the mounting error of the tool.

For example, in the processing of an aperture plate for determining the resolution of an electron microscope, a fine hole having a diameter of several microns or several tens of microns and having a depth of 6 times or more the diameter is ±± for both straightness and roundness. It must be created within 2%.

[0005] When a micro hole having a diameter of 50 microns is to be machined using a conventional cutting method, the diameter of the tool is 50 mm.
The micron and the length are 300 microns or more. The small-diameter tool must have a straightness of 6 μm or less and a roundness of 1 μm or less, and the tool holding portion as well as the tool portion must be formed with high precision. Such a tool can be formed by grinding or electric discharge machining. However, when the finished tool is attached to the processing machine and the center axis of the processing machine and the center axis of the tool are shifted by 0.5 micron, the hole diameter is 1 micron. growing. If the tool is installed at an angle, the deviation will be even greater. Further, the deviation of the axis causes a radial force to be applied to the tool, which may cause damage to the small-diameter tool during machining. In the case of a small-diameter tool, it is necessary to reduce the force applied to the tool in order to prevent breakage even when measuring an installation error or a tool length. For these reasons, it is complicated and difficult to stably form a small-diameter hole by cutting, and the hole diameter is limited to about 100 microns.

As a method for machining a small-diameter hole having a high aspect ratio as described above, there is a micro-discharge machining method as disclosed in Japanese Patent Application Laid-Open No. 6-143043. When this fine electric discharge machining method is used, a fine hole having a diameter of 50 microns can be machined with sufficient accuracy.

[0007]

The problem with machining by the conventional method is that it is difficult to manufacture the tool itself by the cutting method due to a decrease in tool strength due to a reduction in diameter.
At the same time, since the mounting accuracy of the tool directly affects the processing accuracy, high-precision mounting of the tool is essential. However, high-precision positioning is complicated and difficult, so that high-precision processing with a small-diameter tool is difficult. In addition, there are many problems in high efficiency because the setup time at the time of tool change for adjusting the tool mounting error is increased, and the tool is easily damaged during transportation and mounting.

In the above-described conventional method using micro-discharge machining, since the discharge electrode serving as a tool is severely consumed at a volume ratio of 20%, the discharge electrode must be replaced every time one hole is formed. Processing efficiency is lower than cutting. In order to increase the machining efficiency, there are methods of increasing the discharge energy and current density by increasing the discharge voltage and current, increasing the conductivity of the machining fluid, and the like. However, generally, when the discharge energy and the current density are increased, the shape accuracy,
Finished surface roughness is reduced. For this reason, in order to process the above-described fine hole having a diameter of 50 μm and a depth of 300 μm with a desired accuracy, it takes ten and several minutes for one hole including the forming time of the electrode, and it is difficult to improve the efficiency. Further, there is a problem that a non-conductive material cannot be processed.

The present invention solves the above-mentioned problems by cutting the mounting error of the tool in the small-diameter cutting tool having low rigidity, preventing the tool from being damaged by transport and mounting, and shortening the setup time. It is an object of the present invention to provide a method for performing high-precision and high-efficiency drilling of precise and fine parts with a small-diameter tool.

[0010]

SUMMARY OF THE INVENTION The object of the present invention is to provide a structure capable of forming a processing tool on the same processing machine, to create a tool on a processing spindle, to prevent a deviation between a tool center axis and a device spindle,
In addition, the present invention can be achieved by providing a structure for automatically correcting the tool shape, frequently correcting the tool shape, and reducing the number of tool changes.

That is, by providing a structure capable of forming a processing tool on a processing machine, forming a small-diameter tool itself on a processing spindle, and preventing a deviation between the center of the tool and the rotation center of the apparatus main spindle, the processing hole accuracy is improved. Can be improved. Further, since the force applied to the tool due to the deviation of the axis can be reduced, the tool can be prevented from being damaged. Further, by correcting the tool edge on the processing machine, the life of the tool can be extended, and automation of the processing can be facilitated.

Further, since the tool formed by the tool forming unit is positioned with high precision on the processing machine in both length and diameter, the precision of the processing position can be improved.

[0013]

1 to 6 show an embodiment according to the present invention.
This will be described with reference to FIG. FIG. 1 is a schematic external view of a processing machine for realizing the present invention. FIG. 2 shows a state of processing a fine hole in an aperture plate as an embodiment according to the present invention. FIG. 3 is a conceptual diagram of the principle of the tool forming unit, FIG. 4 is a diagram showing the relationship between tool forming conditions and the shape of the forming tool, and FIG. 5 shows an example of a formed tool shape. FIG. 6 is a diagram showing the results of processing time and processing accuracy of the conventional method and the method according to the present invention.
1 is a small-diameter tool, 2 is a work material, 3 is a processing machine spindle, 4 is a processing machine table, 5 is a unit for tool forming, 6 is a fine electrode for tool forming or correction, and 7 is a tool forming. A discharge control circuit 8 is a wire electrode for forming a tool.

The processing method will be described below. A workpiece is mounted on the processing machine table, and a conductive tool material, such as a fine-grain cemented carbide rod, serving as a small-diameter tool is mounted on the processing machine main shaft. The mounting of the tool material does not need to be precise. If the tool material is conductive, high-speed tool steel, etc.
Other tool materials may be used.

As shown in FIG. 1, a tool forming unit that shares a spindle with the processing section is installed on the processing machine in addition to the cutting section. The main shaft of the processing machine is driven by two motors, high speed and low speed, and has an encoder with a rotation accuracy of 1/1000 rotation. By switching the two motors, high-speed rotation of more than 30,000 rotations per minute is possible, and the angle division accuracy at the time of stop and low-speed rotation can be made less than 1/1000 rotation. The main shaft can be further moved and positioned in the z-axis direction by a motor. The table is configured to be able to move in the x and y axis directions by a motor, and the spindle is freely moved between the workpiece on the processing machine and the tool forming unit according to an instruction of the NC device.

As shown in FIG. 3, the tool forming unit comprises a wire electrode for rough machining for forming a small-diameter tool by electric discharge machining, a fine electrode for tool machining, a driving section (not shown), and an electric discharge control circuit. . The electrical discharge machining is a process in which a voltage is applied between an electrode and a workpiece, and the two are brought close to each other until breakdown occurs in an insulating liquid to generate electric discharge, thereby removing each other. The energy generated by the discharge is determined by the applied voltage and the amount of electricity flowing by the discharge. By controlling the energy of this discharge, the processing speed, the surface roughness, and the shape accuracy can be controlled. Further, since the discharge occurs locally, the force applied to the workpiece is small.
For this reason, the processing force when processing the tool material can be reduced as compared with grinding or the like, and it is possible to accurately process a small-diameter tool. The microelectrode installed on the tool forming unit is rotatably supported and can freely change the angle with respect to the tool material. The wire electrode can eliminate apparent wear by feeding the wire, and performs the outer diameter machining of the fine electrode and the tool material with high accuracy.

Next, the processing procedure will be described. In the tool forming unit, a voltage is applied between the tool material and the fine electrode, and the positional relationship between the tool spindle and the fine electrode is determined by the NC device in x, y, z.
By changing the rotation angle of the spindle, the groove of the tool is machined, the cutting edge is machined, or the like to obtain a desired tool shape. As the tool diameter decreases, the edge of the tool cutting edge must likewise be sharpened. Since the shape of the cutting edge affects the force applied to the tool, the cutting edge shape of a small-diameter tool having low rigidity must be controlled with high precision. FIG.
Fig. 4 shows the relationship between the discharge energy and the edge roundness of the tool cutting edge. The small-diameter tool moves onto the tool forming unit while being mounted on the main spindle of the processing machine, and is formed into a desired shape, so that the center, shape, and length of the rotating shaft can be managed with high precision. Further, tools having various shapes as shown in FIG. 5 can be made according to the shape of the target hole.

Next, the workpiece is cut by the prepared small-diameter tool. Since the tool is positioned with high accuracy with respect to all axes of the processing machine, error factors are only caused by the processing phenomenon itself and the method of installing the workpiece.

Further, the tool is moved to the tool forming unit again in accordance with the tool wear to correct the cutting edge. Since the wear of the cutting edge of a tool is usually in the range of several microns, the correction is completed in a few seconds. By correcting the cutting edge without removing the small-diameter tool from the processing machine spindle according to tool wear, the number of tool changes can be reduced and the automation rate can be improved.

Hereinafter, embodiments of the present invention will be described. FIG. 2 shows a state in which a fine hole of an electron microscope component is processed according to the present invention. The fine holes are φ30 microns, the thickness of the processed part of the workpiece is 180 microns, and the required accuracy is roundness,
The straightness is ± 2%. Φ0.8 as tool material
The ultra fine-grain cemented carbide is fixed to the main shaft. A bar electrode of φ300 μm is attached to the fine electrode of the tool processing unit, and the end face is processed and the outer diameter is processed to φ60 μm by a φ0.5 mm wire electrode under the conditions shown in Table 1 to adjust the shape.

[0021]

[Table 1]

Next, the end face of the tool material is machined by a wire electrode under the conditions shown in Table 1, and the outer diameter is machined to a length of 200 microns and a diameter of 30 microns. The tool length is calculated from the z-axis coordinates at the time of this end face processing. Next, a cutting edge is machined from the tool material using the fine electrode having the adjusted shape so as to form a twist drill as shown in FIG. Since the corners of the end face of the fine electrode are severely worn, it is necessary to finish the end face after roughing and then finish the work. 200mm length from 0.8mm tool material
The time required to mold a micron, φ30 micron tool is about 30 minutes. However, the step of tool forming is not necessary except when the tool is broken when changing the shape of the target hole.

Next, the completed tool is moved to the processing section and rotated at a high speed of 30,000 revolutions / minute. Then, a stainless steel (SUS3
04) at a speed of 2 mm / min in the z-direction to form fine holes.

Further, after fifteen micro holes are formed, the small-diameter tool is moved to the tool forming unit again to correct the tool edge at the tip. The time required for the correction is about 15 seconds including the moving time.

FIG. 7 shows a comparison of the processing accuracy and the processing time per hole with the conventional technique when processing is performed by the above method. In the case of micro hole drilling with a diameter of 30 microns and a depth of 180 microns, the machining time was 1 minute and 50 seconds in the electric discharge machining, whereas the machining method according to the present invention was 6 seconds, and the roundness was 3 microns in the conventional cutting. (In the case of a hole depth of 15 microns), but 0.9 microns.

According to the high-precision fine hole processing method of the present invention, similarly, fine holes of optical fiber connectors, nozzles of ink jet printers, fuel injection nozzles of automobiles and the like can be processed with high precision and high efficiency. .

[0027]

According to the present invention, it is possible to form a high-precision micro-hole having a diameter of 0.1 mm or less, which is difficult with conventional cutting, and is 10 times as large as electric discharge machining having the same forming accuracy. The above processing speed can be achieved.

[Brief description of the drawings]

FIG. 1 is a schematic external view of a processing apparatus for realizing the present invention.

FIG. 2 is a diagram showing a state in which a high-precision fine hole is being processed according to the present invention.

FIG. 3 is a conceptual diagram of the principle of a tool forming unit.

FIG. 4 is a diagram showing a relationship between discharge energy and the shape of a forming tool.

FIG. 5 is an example of a tool shape formed by a tool forming unit.

FIG. 6 is a diagram showing a result of processing a micro hole according to the present invention and a conventional method.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Small diameter tool, 2 ... Workpiece, 3 ... Processing machine spindle, 4 ... Processing machine table, 5 ... Unit for tool forming, 6 ... Electrode for tool correction, 7 ... Discharge control circuit, 8 ... Wire electrode.

Claims (5)

[Claims] 1. A structure wherein a machining tool can be formed on the same machining machine by using a machining spindle and a common spindle, and cutting is performed by the tool molded on the machining spindle. Precision micro hole processing method. 2. An electron gun component having fine holes produced by the method of claim 1. 3. An optical fiber connector having a fine hole manufactured by the method of claim 1, and an exchange using the same. 4. A processing tool rotating means, tool positioning means,
A high-precision micro-hole drilling apparatus, comprising: 5. A forming part of a working tool has a rough working wire electrode and a tool working fine electrode, and has a function of forming a finishing electrode with high accuracy by a wire electrode. A high-precision micro-hole processing method and a processing apparatus, wherein a tool is formed by an electrode for use.