JPH10277846A - Electric discharge machine - Google Patents

Abstract

(57) [Problem] To provide an electric discharge machine capable of making a vibration adding mechanism compact, making a device compact, and improving workability such as attachment and detachment of a workpiece. SOLUTION: A processing electrode 1 held by an electrode holding portion 3.
A sample stage 6 for holding the workpiece 2, a beam structure 7 for supporting the sample stage 6 at its movable part 11, and a beam structure 7.
In the electric discharge machine provided with the supporting base 10 for supporting the fixed part 12 of the above and the vibration applying means 8 for vibrating the sample table 6 in the vertical direction Z, the beam structure 7 is provided with the left side beam serving as the movable part. 11, the four beams of the right side beam 12, the upper side beam 13, and the lower side beam 14 serving as the fixed portion form a parallelogram and are urged to return to the reference parallelogram and hinged to each other; Vibration applying means 8
Is configured to apply the vibration a in the vertical direction Z to the vibration applying unit 16a of one of the upper beam 13 and the lower beam 14.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a small electric discharge machine for performing electric discharge machining of a relatively small workpiece at high speed and with high productivity.

[0002]

2. Description of the Related Art This type of electric discharge machine is disclosed in Japanese Patent Application Laid-Open No. HEI 8-112722 shown in FIG. 4 and comprises a machining electrode 1 held by an electrode holder 3 and a sample stage. This is a die-sinking electric discharge machine that performs electric discharge machining by facing a workpiece 2 held on a base 31 with a small gap in a vertical direction Z, and a column 3 fixed to a machining tank 36 containing a machining fluid 5.
There is provided a vibration applying means 37 composed of a piezoelectric element 34 pressurized and connected between the plate 5 and the leaf spring structure 32 fixed to the column 35.

In this conventional example, the piezoelectric element 34 is vertically
When the vibration c is applied to the pressure contact 38 of the distal end beam 39 of the leaf spring structure 32, the leaf spring structure 32 attached to the column 35
The pair of parallel upper and lower leaf springs 33, 33 is elastically deformed in response to the vibration c with the base side beam 40 as a fixed end, and the distal side beam 39 of the plate spring structure 32 is parallel to the base side beam 40. The vibration d in the vertical direction Z while maintaining the posture, the vibration d having the same magnitude as the vibration c is applied to the workpiece 2 via the sample table 31 attached to the distal end beam 39.
Is transmitted.

[0004] The vibration applying means 37 is provided with a vibration d of the workpiece 2.
By promoting the circulation of the machining fluid 5 between the workpiece 2 and the processing electrode 1 by the vibration d, elimination of processing debris on the workpiece 2 and removal of air bubbles, etc., the workpiece being processed is processed. By purifying the surface of No. 2 and stabilizing the discharge characteristics, the processing speed can be increased. In order to perform such an operation, the vibration applying means 37 has, for example, an amplitude of 20 μm.
It is configured using a piezoelectric element 34 that generates a vibration c having a frequency of m and a frequency of 100 Hz.

[0005]

However, the conventional electric discharge machine requires a long piezoelectric element 34 in the vibration direction, that is, the vertical direction Z, in order to stably obtain vibration of sufficient amplitude. The rigidity is also required for the column 35 for fixing the sample, so that the vibration applying means 37 becomes large-scale, and as shown in FIG. There was a problem of inviting. Therefore, even if the speed of the electric discharge machining is increased by the addition of the vibration applying means 37, the workability such as attaching and detaching the workpiece 2 is not good, and the productivity is not sufficiently improved. It is to be noted that it is more difficult to provide the large vibration applying means 37 on the processing electrode 1 side as described above.

Further, in order to efficiently transmit the vibration c from the piezoelectric element 34 to the pressure contact 38, it is necessary to mount the two 34 and 38 in a state where they are pressed against each other with an appropriate pressing force. It takes time and effort to mount the piezoelectric element 34, and it takes time to adjust and mount the vibration applying means 37 even when the piezoelectric element 34 is replaced after its life.

SUMMARY OF THE INVENTION In view of the above problems, it is a primary object of the present invention to provide an electric discharge machine capable of making the vibration applying means compact, making the apparatus compact, and improving the workability of attaching and detaching a workpiece. I do. It is another object of the present invention to provide an electric discharge machine which improves the workability of mounting and maintaining the vibration applying means.

[0008]

According to the present invention, in order to achieve the above object, a processing electrode held by an electrode holding portion, a sample stage holding a workpiece, and a sample stage supported by a movable portion thereof. A beam structure, a supporting base for supporting a fixed portion of the beam structure, and a vibration applying means for vertically vibrating the sample stage, the beam structure, the movable portion, The left side beam, the right side beam, the upper side beam, and the lower side beam serving as the fixed portion are urged to form a parallelogram and return to the reference parallelogram and are hinged to each other, and the vibration The adding means is configured to apply a vertical vibration to the vibration applying section of one of the upper side beam and the lower side beam.

According to the electric discharge machine of the present invention, for example, FIG.
As shown in FIG.
Is set on the upper side beam 13, the amplitude of the vibration applying unit 16 a is adjusted to the movable side and the fixed side hinge joint 2 of the upper side beam 13.
Amplified at an amplification factor corresponding to the ratio A / B of the length A between 6 and 28 and the length B between the vibration applying section 16a and the fixed hinge connecting section 28, and connected to the left side beam (movable section) 11. Since the sample table 6 thus vibrated can be used, the vibration applying means 8 having a small amplitude, that is, a small length in the amplitude direction can be used, and the apparatus can be made compact.

When the vibration applying means is constituted by using a columnar vibration element which is arranged so as to penetrate a beam of the upper beam or the lower beam to which no vibration is applied and which vibrates vertically, most of the vibration element is provided. Since the vibration element can be accommodated inside the beam structure, the height around the beam structure can be reduced as compared with a structure in which the vibration element is disposed outside the beam structure, and the device can be made more compact.

When the vibration element of the vibration applying means is constituted by a piezoelectric element, vibrations of desired amplitude and frequency can be easily controlled electrically and can be stably obtained.

When the piezoelectric element is pressed against the vibration applying portion of one of the upper beam and the lower beam, and the beam is provided with pressing force adjusting means for adjusting the pressing force by a screw rotating operation, the piezoelectric element is A state in which the piezoelectric element is pressed against the vibration applying unit with an appropriate pressing force commensurate with the amount of screw rotation by a simple operation such as tightening the screw of the pressing force adjusting means after placing it on the mounting part without applying preload to the Therefore, the workability of attaching and maintaining the vibration applying means can be improved.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings.

One embodiment of the electric discharge machine of the present invention is shown in FIG.
As shown in FIG. 3, electric discharge machining is performed by facing the machining electrode 1 held by the electrode holder 3 and the workpiece 2 held on the sample table 6 with a small gap in the vertical direction Z. A beam-sinking electric discharge machine, a beam structure 7 for supporting the sample table 6 so that its posture is always constant, a support base 10 for supporting a fixing portion 12 of the beam structure 7, and a sample table 6 The vertical direction Z
And a vibration applying means 8 for vibrating like vibration b. The processing tank 20 contains a processing liquid 5 such as insulating oil so that the workpiece 2 is immersed therein, and a support base 10 for supporting the sample table 6 is fixed.

The electrode holding section 3 is driven by a driving means (not shown) cooperating with the discharge control section 4 to form the machining electrode 1 and the workpiece 2.
It is displaced in the processing direction (downward) with the progress of processing while appropriately maintaining the gap between them. The discharge control unit 4 applies a voltage between the machining electrode 1 and the workpiece 2 to cause a discharge between them, and controls the state of the discharge in cooperation with the driving means.

The sample table 6 has a sample mounting portion 23 that is in contact with the workpiece 2 and serves as a power supply path for electric discharge, and is held on a base 25 via an insulating layer 24. The base 25 has a beam structure. It is formed integrally with the movable part 11 of the body 7 in order to increase the coupling rigidity with the movable part 11.

Here, the reason why the insulating layer 24 is provided is to reduce the influence of the electric current of the electric discharge machining on the piezoelectric element 9 constituting the vibration applying means 8. The layer 24 may not be provided. In addition, if the base portion 25 has sufficient coupling rigidity with the movable portion 11 of the beam structure 7, the two portions 25 and 11 need not be formed integrally.

The beam structure 7 has four beams, a left side beam (movable part) 11, a right side beam (fixed part) 12, an upper side beam 13 and a lower side beam 14 having a large width in the width direction Y (see FIG. 3). When viewed from the side, it is made of steel material integrally connected in a frame shape having a rectangular reference shape. The four connecting portions of these four beams 11 to 14 are formed by thin hinge portions 26, 27, 28, and 29 provided with semicircular groove-like cuts from the upper surface and the lower surface over the entire width direction Y. ing. The right side beam 12 is provided on the standing portion 10 of the support base 10.
a, and the beam 11 on the left side is
And is also provided integrally with the base 25, and also serves as a rising wall of the base 25.

As will be described later, when the external force in the vertical direction is applied to the upper side beam 13, the thin hinge portions 26 to 29
Due to the structure of the parallelogram formed by the four beams 11 to 14, the left side beam 11 is constantly displaced up and down while maintaining its posture, and cooperates to return the parallelogram to the reference rectangle. Work to store resilience. That is, as shown in FIG. 2, the position of the beam structure 7 is adjusted by the elastic restoring force while the posture of the sample stage 6 on the movable portion side is kept constant by the parallelogram structure. Support by returning to the initial position.

The vibration applying means 8 comprises a piezoelectric element 9 which is driven to expand and contract in the longitudinal direction by a driving section 19. The piezoelectric element 9 has a fixed end 9b fixed to a mounting hole 10b below the support base 10 with a fixing ring 18, and a free end 9a with an upper beam 13
, And a vibration a in the vertical direction Z is applied to the vibration applying section 16a located at the center in the length direction X and the width direction Y. With this structure, as shown in FIG. 2, the amplitude of the vibration a is reduced by the length A between the movable-side and fixed-side thin hinge portions 26, 28 of the upper beam 13, the vibration applying portion 16a, and the fixed-side thin hinge portion 28. Amplification is performed at an amplification factor corresponding to the ratio A / B to the length B between the two, and the sample stage 6 connected to the left side beam 11 of the movable unit can be vibrated by the amplified vibration b.

Further, since the piezoelectric element 9 is provided so as to penetrate through the hole 14a which is provided at the center of the lower beam 14 and penetrates vertically so as not to contact the inner surface, the piezoelectric element 9 is protruded above the beam structure 7. And the equipment is compact.

The vibration applying section 16a is formed at the lower end of a screw 16 screwed into a screw hole 13a penetrating through the center of the upper side beam 13, and the screwing operation of the screw 16 causes the piezoelectric element 9 to rotate. By being pressed against the free end 9a at the upper end, a pressing force due to the elastic restoring force of the thin hinge portions 28, 29 of the beam structure 7 is applied between the two 16a, 9a, and the pressing force can be easily adjusted to an appropriate magnitude. Therefore, when the piezoelectric element 9 is mounted, the screw 16 may be tightened after the piezoelectric element 9 is disposed between the vibration applying section 16a and the fixing ring 18 without applying a preload.

The screw 16 is screwed with a locking nut 17 to prevent the screw 16 from rotating after the adjustment of the pressing force is completed and to eliminate the backlash of the screw 16 so that the vibration a
Nut to prevent loosening.
Tighten 7 firmly.

The free end 9a of the piezoelectric element 9 is formed in a convex shape, and the vibration applying portion 16a of the screw 16 is formed in a concave shape slightly larger than the convex shape of the free end 9a.
a, 9a so as not to be disconnected from the side, and the thin hinge portion 2 of the upper side beam 13 accompanying expansion and contraction of the piezoelectric element 9.
The distance B between the vibration applying portion 16a and the thin hinge portion 28 is always kept constant even when the screw 16 is turned around eight times, that is, the tilting of the screw 16, and a harmful force such as a bending force is not applied to the piezoelectric element 9. I have to.

In the above embodiment, the beam structure 7 is configured such that the four beams 11 to 14 are connected by the four thin and narrow hinge portions 26 to 29 formed integrally with them. The present invention is not limited to this, and the four thin hinge portions may be constituted by different elastic members. Further, the right side beam 12 may be integrated with the support base 10.

In the above embodiment, the vibration applying means 8
Although the piezoelectric element 9 is used in this embodiment, a magnetostrictive element such as a ferrite vibrator may be used instead.

[0027]

According to the electric discharge machine of the present invention, the amplitude of the vibration applying portion of one of the upper side beam and the lower side beam to which the vibration is applied by the vibration applying means is adjusted to both the movable side and the fixed side of the beam. The sample stage connected to the left side beam (movable part) can be vibrated by amplifying with an amplification factor corresponding to the ratio between the length between the hinge connection part and the length between the vibration applying part and the fixed side hinge connection part. Therefore, it is possible to use vibration applying means having a small amplitude, that is, a small length in the amplitude direction, and the device can be made compact. Therefore, workability such as attachment and detachment of a workpiece can be improved, and productivity can be improved.

If the vibration applying means is constituted by using a columnar vibration element which penetrates the upper beam or the lower beam to which the vibration is not applied and which vibrates vertically, most of the vibration element is provided. Since the vibration element can be accommodated inside the beam structure, the height around the beam structure can be reduced as compared with a structure in which the vibration element is disposed outside the beam structure, and the apparatus can be made more compact.

If the vibration element of the vibration applying means is constituted by a piezoelectric element, vibrations of a desired amplitude and frequency can be easily controlled electrically and can be stably obtained.

If the piezoelectric element is pressed against the vibration applying portion of one of the upper beam and the lower beam, and the beam is provided with a pressing force adjusting means for adjusting the pressing force by a screw rotating operation, the piezoelectric element is A state in which the piezoelectric element is pressed against the vibration applying unit with an appropriate pressing force commensurate with the amount of screw rotation by a simple operation such as tightening the screw of the pressing force adjusting means after placing it on the mounting part without applying preload to the Therefore, the workability of mounting and maintaining the vibration applying means can be improved, and the productivity can be improved.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of an electric discharge machine according to the present invention.

FIG. 2 is a principle view illustrating an embodiment of the electric discharge machine of the present invention.

FIG. 3 is a perspective view showing one embodiment of a sample stage of the electric discharge machine according to the present invention.

FIG. 4 is a schematic view showing a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Processing electrode 2 Workpiece 3 Electrode holding part 6 Sample stand 7 Beam structure 8 Vibration addition means 9 Piezoelectric element (vibration element) 10 Support base 11 Left side beam (movable part) 12 Right side beam (fixed part) 13 Upper side Beam 14 Lower beam 16 Screw (pressing force adjusting means) 16a Vibration applying part a Vibration of vibration applying part b Vibration of sample stage Z Vertical direction

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Ken Masaki 1006 Kazuma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. 72) Inventor Hiroyuki Funazo 1006 Kadoma, Kadoma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd.

Claims (4)

[Claims] A processing electrode held by an electrode holding portion;
A sample stage that holds the workpiece, a beam structure that supports the sample stage at its movable portion, a support base that supports a fixed portion of the beam structure, and vibration applying means that vertically vibrates the sample stage. In the electric discharge machine having the beam structure, the four beams of the left side beam serving as the movable portion, the right side beam serving as the fixed portion, the upper side beam, and the lower side beam form a parallelogram, and the reference parallelogram is formed. The vibration applying means is configured to apply a vertical vibration to a vibration applying unit of one of the upper side beam and the lower side beam. An electric discharge machine. 2. The vibration applying means comprises a columnar vibrating element which is arranged so as to penetrate a beam of the upper side beam or the lower side beam to which vibration is not applied and which vibrates in a vertical direction. The electrical discharge machine described. 3. The electric discharge machine according to claim 1, wherein the vibration element of the vibration applying means comprises a piezoelectric element. 4. A piezoelectric element is pressed against a vibration applying portion of one of an upper beam and a lower beam, and the beam is provided with a pressing force adjusting means for adjusting the pressing force by a screw rotating operation. 3. The electric discharge machine according to 3.