JPH06320338A - Electric discharge machining electrode and electric discharge machine - Google Patents

Abstract

PURPOSE:To provide an electric discharge machining electrode, capable of vibrating, which can be easily used in an electric discharge machine. CONSTITUTION:A piezoelectric ceramic layer 2 and internal electrodes 3a, 3b are alternately laminated, to constitute a layered product, and the internal electrodes 3a, 3b,..., laminated on every other layer, are conducted in the inside of the layered product and connected to a chuck mounting part 4. The internal electrodes 3b, 3b..., laminated on every other layer, are conducted in the inside of the layered product and drawn out from an electrode take out port 5 to the outside of the electrodes by a lead wire.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric discharge machining electrode and an electric discharge machine. Specifically, the present invention relates to an electric discharge machining electrode used for die-sinking electric discharge machining and an electric discharge machine for using the electrode.

[0002]

2. Description of the Related Art Conventionally, there is an electric discharge machine for die-sinking electric discharge machining which can vibrate the electrode for electric discharge machining in order to reduce the electrode wear rate and improve the machining speed (for example, 19
Proceedings of the 91st Spring Meeting of the Japan Society for Precision Engineering
p. 443-444). FIG. 5 is a schematic structural diagram in which the electric discharge machine C is partially broken, and an electrode vibrating section 32 is attached to a spindle 31 of the electric discharge machine C.

The electrode vibrating section 32 is composed of a composite vibration exciter 33 for generating vibration applied to the electrode 36, and power sources 34, 35 for applying a voltage to the composite vibration exciter 33. Thus, the composite vibrator 33 generates longitudinal vibration at a constant frequency f ₁ when an AC voltage is applied by the power source 34, and flexural vibration at a constant frequency f _b when an AC voltage is applied by the power source 35. To occur. In addition, the power supplies 34, 35
If an AC voltage is applied simultaneously from the electrode 3 attached to the tip of the composite vibrator 33, a composite vibration is generated by combining the longitudinal vibration with the frequency f _l and the flexural vibration with the frequency f _b.
6 can be vibrated vertically and horizontally.

[0004]

However, the electric discharge machine C having such a structure requires the electrode vibrating portion 32 for vibrating the electrode 36 vertically and horizontally.
It was necessary to provide the composite shaker 33, the power supplies 34 and 35 for vibration, and the like.

Therefore, when an electrode vibrating device such as the electrode vibrating part 32 is introduced into a conventional electric discharge machine, it is needless to say that the vibrating device is newly purchased, or the electrode mounting part is replaced or the entire surface is replaced. Needed to be improved. In addition, it is necessary to newly install a power source for vibration,
It cost a lot of money.

Further, there is a problem that the electrode vibrating device, the power source for vibrating, etc. are larger and more complicated than the conventional electric discharge machine.

The present invention has been made in view of the drawbacks of the above conventional examples, and an object of the present invention is to provide an electric discharge machining method which can be easily performed while vibrating an electric discharge machining electrode. .

[0008]

In the electric discharge machining electrode of the present invention, piezoelectric ceramics and internal electrodes for applying an electric field to the piezoelectric ceramics are alternately laminated, and the laminated internal electrodes are electrically connected every other layer. It is characterized by being composed of a laminated body.

It is also possible to provide an external electrode on each side of the laminated body for electrically connecting the internal electrode to every other layer, and cover the external electrode with an insulator.

A first electric discharge machine according to the present invention comprises an electric discharge machining electrode according to claim 1 or 2, and a vibration power source for applying a voltage for vibrating the electric discharge machining electrode. It is characterized in that a power supply for electric discharge machining for applying a voltage for electric discharge machining is provided.

A second electric discharge machine according to the present invention is an electric discharge machining electrode according to claim 1 or 2, and a power supply for vibrating the electric discharge machining electrode and applying a voltage for performing electric discharge machining. It is characterized by having and.

[0012]

The electric discharge machining electrode of the present invention comprises a laminated body in which piezoelectric ceramics and internal electrodes for applying an electric field to the piezoelectric ceramics are alternately laminated, and the laminated internal electrodes are electrically connected every other layer. When a pulse voltage or an AC voltage having a constant frequency is applied between the internal electrodes sandwiching the piezoelectric ceramic, the piezoelectric ceramic expands and contracts to vertically vibrate the electric discharge machining electrode at a constant vibration cycle.

Therefore, in this electric discharge machining electrode, since the electrode itself vibrates due to expansion and contraction of the piezoelectric ceramics, a vibrating device for vibrating the electric discharge machining electrode is unnecessary, and only a vibration power source is provided. Good. Further, even the conventional electric discharge machine can be easily applied only by adding an improvement for applying a vibration voltage to the electric discharge electrode. Further, the electric discharge machine does not become large and does not become complicated.

Further, since the piezoelectric ceramics themselves also act as an electrode for electric discharge machining and can generate electric discharge, the surface roughness of the machined surface which has not been improved only by vibrating the electrode in the related art, particularly the machined surface on the side surface of the electrode. The surface roughness of can be improved, and the wear resistance and corrosion resistance of the electric discharge machining electrode can be improved.

Further, by providing external electrodes on the side surface of the laminated body for electrically connecting the internal electrodes every other layer, and covering the external electrodes with an insulator, the conventional piezoelectric element can be easily converted to an electric discharge machining electrode. can do.

According to the first electric discharge machine of the present invention, a power supply for vibration application for applying a voltage for vibrating the electrode for electric discharge machining, and a power supply for electric discharge machining for applying a voltage for performing electric discharge machining. Therefore, the applied voltage for vibrating the electric discharge machining electrode can be applied separately from the voltage for electric discharge machining, and the electric discharge machining electrode can be vibrated at an arbitrary vibration cycle or arbitrary vibration width. it can. Therefore, by changing the frequency or voltage of the applied voltage and adjusting the vibration period or vibration width, it is possible to improve the processing speed, reduce the electrode wear rate, or improve the surface roughness of the processed surface.

According to the second electric discharge machine of the present invention, since the electric discharge machining electrode is vibrated and a power supply for applying a voltage for electric discharge machining is provided,
It is not necessary to separately provide a power source for vibration, and the electric discharge machine can be further downsized.

Further, since the electric discharge machining electrode vibrates in synchronization with the generation of the electric discharge pulse, the electric discharge machining electrode vibrates only during electric discharge, thereby reducing power consumption and extending the life of the piezoelectric ceramic. Therefore, the running cost can be reduced.

[0019]

FIG. 1 is a perspective view of an electrode 1 for electric discharge machining which is an embodiment of the present invention. In the electrode 1, the silicon-based piezoelectric ceramic layers 2 and the thin plate-shaped internal electrodes 3a and 3b made of Cu or the like are alternately laminated to form a laminated body, and the internal electrodes 3a and 3a are laminated every other layer. 3a, ... Are conducted inside the laminated body, and the chuck mounting portion 4 at the upper end of the laminated body
Electrically connected to. Further, the remaining internal electrodes 3b, 3b, ... Which are laminated every other layer are conducted inside the laminated body,
A lead wire (not shown) or the like pulls out from the electrode lead-out port 5 on the upper end surface of the laminate.

The chuck mounting portion 4 of the electrode 1 is mounted on the chuck 12 of the electric discharge machine A as shown in FIG. 2 and set on the electric discharge machine A. The chuck 12 is connected to one end of a discharge circuit 17 including a power supply 13, a control circuit 14 for controlling the voltage applied to the electrode 1, a resistor 15 and the like, and the other end of the discharge circuit 17 is connected to the processing stage 19.
, Which constitute the electrode 1, are alternately connected to the discharge circuit 17 via the chuck 12 and the chuck mounting portion 4, and are placed on the processing stage 19. An electric discharge is generated between the work piece 20 and the work piece 20. Further, the remaining internal electrodes 3b, 3b, ...
The lead wire pulled out further connects the spindle 16 of the electric discharge machine A to the ground circuit 18.

Therefore, the electrode 1 is connected through the discharge circuit 17.
When a discharge voltage pulse-controlled by the control circuit 14 to a constant frequency f1 is applied between the workpiece 20 and the workpiece 20, the voltage is applied between the internal electrode 3a and the internal electrode 3b, and the piezoelectric ceramic layer 2 Causes expansion and contraction at frequency f1
Oscillates vertically with a vibration cycle of 1 / f1. Next, when the electrode 1 is gradually brought closer to the work piece 20, an electric discharge is generated between the work piece 20 and the internal electrode 3a of the electrode 1 and the piezoelectric ceramic layer 2, and the work piece 20 is subjected to electric discharge machining. . In the electric discharge machine A, the vibration cycle of the electrode 1 is the reciprocal of the pulse number of the discharge voltage applied to the electrode 1 (1 /
f1), which is equal to the actual electrical discharge machining cycle.
Further, since the vibration width of the electrode 1 is proportional to the magnitude of the discharge energy, the control circuit 14 changes the frequency f1 of the discharge voltage to change the discharge voltage. The width can be adjusted.

Therefore, by using the electrode 1, it is possible to easily perform electric discharge machining while vibrating the electrode 1, and improve the surface roughness of the machined surface of the workpiece 20 and the machining speed of the electric discharge machine A. You can

Further, in the conventional electric discharge machine in which the electrode itself could not be vibrated, it is only necessary to improve so that the electrode take-out port 5 and the ground circuit 18 can be connected.
Since it is not necessary to provide a power supply device for vibration separately from the electric discharge circuit 17, the electrode 1 can be easily used like the electric discharge machine A. Further, since the electrode exciting device and the like are not necessary, the electric discharge machine A can be made smaller than the conventional electric discharge machine C for exciter.

In the electric discharge machine A, the ground circuit 18
One of the internal electrodes without providing (for example, the internal electrode 3b)
Can also be left electrically floating. In this case, when the electrode 1 is gradually brought closer to the work piece 20, discharge is started between the electrode 1 and the work piece 20, and at the same time, the piezoelectric ceramic layer 2 starts to expand and contract, and the work piece is processed. Two
Electric discharge machining is performed at 0. Further, when the electrode 1 is moved away from the workpiece 20, the discharge is stopped and the voltage is not applied to the piezoelectric ceramic layer 2 at the same time, so that the piezoelectric ceramic layer 2 does not expand or contract and the electrode 1 does not vibrate. Therefore, it is possible to reduce the power consumption, extend the life of the electrode 1, and reduce the running cost.

FIG. 3 shows another electric discharge machine B using the electrode 1.
2 is a schematic configuration diagram of FIG. Attach the chuck mounting portion 4 of the electrode 1 to the chuck 12 of the electric discharge machine B,
Set to. One end of a discharge circuit 17 is connected to the chuck 12, and a discharge voltage is applied to the internal electrodes 3a, 3a, ... Of the electrode 1 via the chuck mounting portion 4. Further, the internal electrodes 3a and 3b are electrically connected from the spindle 16 to the drive circuit 21 via lead wires drawn out from the chuck mounting portion 4 and the electrode lead-out port 5.

Therefore, when a pulse voltage or an AC voltage is applied from the excitation power source 22 at a constant frequency f2, the voltage can be applied to the piezoelectric ceramic layer 2 of the electrode 1, and the electrode 1 vibrates with a vibration period of 1 / f2. It causes vibration up and down.
On the other hand, when a discharge voltage is applied to the discharge circuit 17 at a constant frequency f1, a discharge is generated between the electrode 1 and the workpiece 20,
The workpiece 20 is to be electric discharge machined.

If the drive circuit 21 is provided independently of the discharge circuit 17 as in the electric discharge machine B, the piezoelectric ceramic layer 2 can be expanded and contracted independently of the discharge.
Therefore, it is possible to perform the electric discharge machining with the electric discharge pulse of the frequency f1 while vibrating the electrode 1 up and down with an arbitrary vibration period 1 / f2 and an arbitrary vibration width, and to obtain a machined surface having a better surface roughness and a better surface roughness. The processing speed can be obtained.

Further, in the conventional electric discharge machine in which the electrode itself could not be vibrated, the lead wire taken out from the chuck mounting portion 4 of the electrode 1 and the electrode take-out port 5 can be connected to the drive circuit 21. The electrode 1 can be easily used by improving the above and providing a power supply 22 for vibration.

FIG. 4 shows an electrode 11 for electric discharge machining which is another embodiment of the present invention. The electrode 11 is a laminated body formed by alternately laminating the piezoelectric ceramic layers 2 and the internal electrodes 3a, 3b, ..., And the internal electrodes are laminated every other layer by the external electrode 6a provided on one side surface of the laminated body. 3a, 3
, are connected to each other, and the remaining internal electrodes 3b, 3b, ..., which are stacked every other layer, are connected by the external electrode 6b provided on the other side surface of the stacked body. In addition, the external electrode 6
The outer sides of a and 6b are covered with an insulator 7, and the outer electrode 6
a and 6b are drawn out of the electrode 11 by lead wires 8 and 8, respectively.

The electrode 11 is attached to the chuck 12 of the electric discharge machine A as shown in FIG. 2, and the external electrode 6a and the electric discharge circuit 17 and the external electrode 6b and the ground circuit 18 are connected by the lead wires 8 and 8. It can be electrically connected. Therefore, the control circuit 14 controls the constant frequency f1 between the electrode 11 and the workpiece 20 through the discharge circuit 17.
When a pulse-controlled discharge voltage is applied to the piezoelectric ceramic layer 2, the piezoelectric ceramic layer 2 expands and contracts at a frequency f1 and the electrode 11 vibrates in a cycle
/ F1 causes stretching vibration in the vertical direction. Further, when the electrode 11 is brought closer to the workpiece 20, the electrode 11 and the workpiece 2
An electric discharge is generated between the electric field and 0, and the workpiece 20 is subjected to electric discharge machining.

Further, as shown in FIG. 3, the chuck 1 of the electric discharge machine B provided with a drive circuit 21 independent of the electric discharge circuit 17.
The external electrodes 6a and 6b may be connected to the drive circuit 21 by attaching the external electrodes 6a and 6b.

It should be noted that the insulator 7 may be applied not only to the outside of the outer electrodes 6a and 6b, but also to the exposed side surface of the laminate, as on the entire outer periphery of the laminate. You may decide to form the electrode part electrically connected with the internal electrode 3a of the lower end of the electrode 11.

[0033]

According to the electric discharge machining electrode of the present invention, the piezoelectric ceramics and the internal electrodes for applying an electric field to the piezoelectric ceramics are alternately laminated, and the laminated internal electrodes are electrically connected to each other. An electric field can be applied to the piezoelectric ceramic to cause expansion and contraction at a constant frequency, and the electric discharge machining electrode can be vertically vibrated.

This electric discharge machining electrode does not require a vibrating device for vibrating the electric discharge machining electrode, and only needs to provide a power supply for vibration. Therefore, even the conventional electric discharge machine can be easily applied only by adding an improvement for applying the vibration voltage to the electric discharge electrode.
Further, the electric discharge machine does not become large and does not become complicated.

Furthermore, since the piezoelectric ceramics can also act as an electric discharge machining electrode, it is possible to improve the surface roughness of the machined surface which has not been improved simply by vibrating the electric discharge machining electrode, and the electric discharge machining electrode can be improved. It is possible to improve the wear resistance and corrosion resistance of the.

Further, since the external electrodes for conducting the internal electrodes every other layer are provided on the side surfaces of the laminate and the external electrodes are covered with the insulator, the conventional piezoelectric element can be easily used as an electrode for electric discharge machining. Can be diverted.

According to the first electric discharge machine of the present invention, since the excitation power supply and the electric discharge power supply are provided, the electric discharge electrode is vibrated at an arbitrary vibration cycle and an arbitrary vibration width. Can be made. Therefore, by adjusting the frequency or voltage of the applied voltage, it is possible to improve the processing speed, reduce the electrode wear rate, or improve the surface roughness of the processed surface.

According to the second electric discharge machine of the present invention, since the electric discharge machining electrode is vibrated and a power supply for applying a voltage for electric discharge machining is provided,
It is not necessary to separately provide a power source for vibration, and the electric discharge machine can be further downsized.

Further, since the electric discharge machining electrode vibrates in synchronization with the generation of the electric discharge pulse, the electric discharge machining electrode only vibrates at the time of electric discharge, thereby reducing power consumption and extending the life of the piezoelectric ceramic. Therefore, the running cost can be reduced.

[Brief description of drawings]

FIG. 1 is a perspective view of an electric discharge machining electrode according to an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of an electric discharge machine that is an embodiment of the present invention.

FIG. 3 is a schematic configuration diagram of an electric discharge machine which is another embodiment of the present invention.

FIG. 4 is a side view of an electric discharge machining electrode which is another embodiment of the present invention.

FIG. 5 is a schematic configuration diagram showing an electrode vibrating portion of a conventional electric discharge machine.

[Explanation of symbols]

 2 Piezoelectric ceramic layers 3a, 3b Internal electrodes 6a, 6b External electrodes 8 Lead wire 12 Chuck 17 Discharge circuit 21 Drive circuit

Claims (4)

[Claims] 1. An electric discharge machine comprising a piezoelectric ceramic and an internal electrode for applying an electric field to the piezoelectric ceramic, which are alternately laminated, and the laminated internal electrodes are electrically connected every other layer. Electrodes. 2. The electrical discharge machining according to claim 1, wherein external electrodes for electrically connecting the internal electrodes to every other layer are provided on a side surface of the laminated body, and the external electrodes are covered with an insulator. electrode. 3. The electric discharge machining electrode according to claim 1 or 2, an excitation power supply for applying a voltage for vibrating the electric discharge machining electrode, and a voltage for performing electric discharge machining. An electric discharge machine equipped with a power supply for electric discharge machining. 4. The electric discharge machining electrode according to claim 1 or 2, and a power supply for vibrating the electric discharge machining electrode and applying a voltage for performing electric discharge machining. Electric discharge machine.