JPH09108943A - Electric discharge machining device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to perform roundness improved air perforative machining without immersing the whole subject substance into a machining fluid and to shorten machining time. SOLUTION: The location of a subject substance 11 on which perforative machining is to be performed by a set of housings 14, 15 is partially sealed. An insulating seal 16 is provided between the subject substance 11 and the interior of the housing 15. An electrode 18 is inserted through the insulating seal 16 and the tip of the electrode 18 is made to come in contact with the subject substance 11. The other end of the electrode 18 is connected to an electrode rotating motor 27. A drive unit 26 ball screw and a gear are provided on the electode rotating motor 27 so that it can be moved back and forth by a servo motor. The electrode 18 is provided with a machining fluid passage 33, through which machining fluid 2 runs, and an injection nozzle 32 for injecting machining fluid 2 towards the subject substance 11. The electrode 18 rotates by the electrode rotating motor 27 and repeats forward and backward motion by the drive unit 26 by which perforative machining is performed.

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 apparatus for punching a workpiece such as a plate material under air.

[0002]

2. Description of the Related Art A first conventional example of an electric discharge machining apparatus for punching a plate material will be described with reference to FIG. As shown schematically in FIG. 5, the working fluid 2 is stored in the water tank 1, and the working fluid 2
The work piece 3 is installed via the pedestal 4, the electrode 5 is provided on the work piece 3 by being immersed in the working liquid 2, and the electrode 5 is attached to the drive unit 6 installed in the air. The drive unit 6 is attached to the control unit 7.

With such an electric discharge machining apparatus, the electrode 5 is lowered from the drive unit 6 to come into contact with the workpiece 3 in the machining liquid, and the electrode 5 is discharged in water to form the hole 8. The drive unit 6 is the control unit 7
The vertical movement and applied voltage are controlled by.

FIG. 6 shows a second example of a conventional electric discharge machining apparatus. The apparatus of FIG. 6 differs from that of FIG. 5 in a water tank 1.
Is large, the drive unit 6 is immersed in the machining liquid 2, the electrode 5 attached to the drive unit 6 is surrounded by the cylindrical body 9 together with the drive unit 6, and the drive unit 6 is connected to the control unit 7 by the control cable 10. There is something to do.

In this second example, the work piece 3 and the electrode 5 are attached to the working fluid 2 in the water tank 1, the driving portion 6 having a waterproof structure is dipped by the cylindrical body 9, and the hole 8 is provided through the control cable 10. Is open.

[0006]

The conventional electric discharge machining apparatus shown in FIGS. 5 and 6 is not so difficult when the work piece 3 is short, small and light, but the work piece 3 is long. There is a problem in that it is not possible to perform perforation processing because an object or an assembly part of a large-scale device cannot enter the water tank 1 and cannot be entirely immersed in the working liquid 2 in the water tank 1.

Further, as the work piece 3 becomes larger, the water tank 1 becomes larger and the machining liquid 2 is required accordingly, and the roundness of the machining hole is deviated and the machining time becomes longer, which is not realistic. . As described above, in the conventional electric discharge machining apparatus, there is a problem that the hole-machining portion of the workpiece 3 must be immersed in the machining liquid 2 for machining.

The present invention has been made to solve the above problems, and it is possible to perform drilling with improved roundness in the air without immersing the entire workpiece in a working liquid. Another object of the present invention is to provide an electric discharge machining device for drilling, which can shorten the machining time.

[0009]

SUMMARY OF THE INVENTION According to the present invention, a portion to be punched in a workpiece is locally sealed by a pair of housings having one end closed and the other end opened, and the workpiece and the housing are sealed. An insulating seal is provided inside the opening side, an electrode is inserted through this insulating seal, the tip of this electrode is brought into contact with the workpiece, and the other end of this electrode is connected to an electrode rotation motor. The electrode rotation motor is attached to the drive unit, the ball screw is attached to this drive unit, this ball screw is attached to the servomotor via the gear, and the machining liquid flow path for flowing the machining liquid into the electrode is attached. And a jet nozzle for jetting the jet toward the workpiece.

Further, the present invention is characterized in that a drainage port for the working fluid is provided in the insulating seal, and the drainage port is connected to a vacuum unit by air supply. Further, according to the present invention, the electrode has an arcuate surface or a tapered surface formed at a tip end portion thereof, a plurality of grooves formed on an outer peripheral surface thereof, and a machining liquid jetting flow passage formed at a tip end portion from a central portion in an axial direction. Is characterized by.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of an electric discharge machine according to the present invention will be described with reference to FIGS. 1 and 2. 1 is a plan view showing a part of the present embodiment in section, and FIG. 2 is a plan view seen from the vertical direction in FIG.

In FIG. 1 and FIG. 2, reference numeral 11 indicates a long rod-shaped workpiece, and this embodiment is the workpiece.
This is an example of forming a through hole 12 in 11 by electric discharge machining. The workpiece 11 is closed at one end so as to surround one side of the through hole 12 formed by drilling, and a chip recovery hole is formed inside.
A first housing 14 having 13 is provided, and a second housing 15 is provided opposite to the first housing 14 so as to surround the other side of the workpiece 11 and open at both ends. The first housing 14 and the second housing 15 are fixed as a pair of housings.

An insulating seal member 16 is provided in the second housing 15 so as to come into contact with the workpiece 11 via an O-ring 17. An O-ring 17 is provided at a portion where the insulating seal member 16 and the first housing 15 are in contact with the workpiece 11 to hermetically seal.

The insulating seal member 16 is formed with an electrode insertion hole 19 for inserting the electrode 18 and a drain port 21 communicating with a drain pipe 20 provided outside the second housing 15 in a direction perpendicular to the electrode insertion hole 19. . A drain nozzle 22 is connected to the drain 21, and a drain pipe 20 is connected to the drain nozzle 22. A first plate 23 is provided at the open end of the second housing 15.

One end of a pair of guide rods 24 is connected to the first plate 23, and the second plate 25 is connected to the other end of the guide rods 24. A drive unit 26 is attached to the pair of guide rods 23 so as to be movable back and forth, and the drive unit 26 is provided with an electrode rotation motor 27.

A rear end of the electrode 18 is connected to the electrode rotating motor to rotate the electrode 18. A ball screw 28 is attached to the drive unit 26, and the ball screw 28 meshes with a gear 29 attached to the first plate 23,
Reference numeral 29 is connected to the gear of the servo motor 30, and the ball screw 28 is rotated by the drive of the servo motor 30 via the gear and can be moved forward or backward together with the electrode rotation motor 27.

A control cable 31 is connected to the electrode rotating motor 27 and the servo motor 30, and the servo motor 30 is fixed to the guide rod 24. The control cable 31 is connected to a separate control panel (not shown).

The electrode 18 has a circular tip and is formed by arranging a plurality of jetting nozzles 32 for the working fluid 2 in a radial pattern, and a working fluid flow communicating with the jetting nozzle 32 is formed in the central portion along the axial direction. A path 33 is formed. A water supply nozzle 34 is connected to the end of the processing liquid channel 33, the water supply nozzle 34 is connected to a water supply pipe 35, and the water supply pipe 35 is connected to a processing liquid tank (not shown).

On the other hand, the drainage pipe 20 is connected to the vacuum unit 36, and the vacuum unit 36 is connected to the air pipe 37 and the main drainage pipe 38. When the air is fed from the air pipe 37 into the vacuum unit 36 at a high pressure. The machining flow after electric discharge machining that has flowed out of the electrode 18 can be made to flow to the drain main pipe 38 through the drain pipe 20 and the vacuum unit 36.

Further, a contact 39 made of carbon or the like penetrates through the insulating seal member 16 and the lower housing 15 and a spring 40
One end of the contact 39 contacts the outer surface of the tip of the electrode 18. A minus terminal 41 is connected to the contact 39, and a plus terminal 42 is connected to the second housing 15.

A lead wire 43 is connected to the minus terminal 41 and the plus terminal 42, and a voltage is applied from a power source (not shown) to generate a discharge between the workpiece 11 and the electrode 18. Lead wire 43
Is connected to a control panel (not shown).

FIGS. 3 and 4 show the essential parts of the electrode of the second embodiment of the present invention. The first electrode shown in FIG.
18a has a plurality of grooved portions 44 formed on the outer peripheral surface and an arcuate surface 45 formed at the tip end. The second electrode 18b shown in FIG. 4 has a plurality of grooved portions 44 formed on the outer peripheral surface. The taper surface 46 is formed at the tip portion, and the other portions are similar to those of the electrode 18 shown in FIGS. These groove processing portions 44 serve as flow paths for collecting the machining liquid after electric discharge machining and can be formed in the electrode 18 shown in FIG.

Next, the operation of the above embodiment will be described.
The workpiece 11 locally sealed by the first housing 14 and the second housing 15 is hermetically sealed by the O-ring 17. The machining liquid 2 is jetted toward the workpiece 11 from the jet nozzle 32 at the tip end through the machining liquid channel 33 in the electrode 18 by the water supply pipe 35 connected to the water supply nozzle 34.

The electrode 18 is rotated by the electrode rotation motor 27, and the servo motor 30 repeatedly moves forward and backward. In the forward / backward operation, a rotational force is applied from the servo motor 30 to the gear 29 to rotate the ball screw 28.
Rotation causes the drive unit 26 to move forward and backward,
18 also moves back and forth. These operations are controlled by a control panel (not shown)
It is performed by

The machining power source discharges between the workpiece 11 and the electrode 18 by the minus terminal 41 to the plus terminal 42, and the hole is formed to form the through hole 12. The machining liquid 2 is, for example, as shown in FIGS. 3 and 4 together with the machining waste generated during the machining of the through hole 12.
From the grooved portion 44 formed on the electrodes 18a and 18b shown in FIG.
It is discharged to the water distribution pipe 20 through 21. Working fluid 2 discharged
Is discharged while maintaining a negative pressure inside the water distribution pipe 20 by the air from the air pipe 37 supplied to the vacuum unit 36. The chips after electrical discharge machining are stored in the chip collection hole 13.

According to the present embodiment, however, by providing a pair of housings for locally sealing the work piece, the work piece is not soaked in the working liquid as in the conventional case, and the work piece is not processed. Since the machining liquid can be supplied and discharged only to the hole-drilling portion of the object, it is possible to perform hole machining by electric discharge in the air.

By rotating the electrode, the roundness at the time of drilling is improved, and the side surface of the electrode is provided with a groove, and the synergistic action of the vacuum unit improves the discharge of machining waste at the time of machining and shortens the machining time. .

When the machining fluid is discharged, a vacuum unit is used, so that the inside of the discharge pipe can be maintained at a negative pressure, so that the discharge of the processing waste can be improved and the diameter of the discharge pipe can be reduced to facilitate the handling of the device. Become.

[0029]

As described above, according to the present invention, it is easy to locally seal a hole drilling part of a workpiece and the working fluid can be locally supplied and drained. It can be installed below to enable hole machining by electric discharge. Further, by rotating the electrode, the roundness of the machined hole is improved, and the machining of the machining side is shortened because the machining of the side surface of the electrode and the vacuum unit improve the discharge of machining chips.

[Brief description of the drawings]

FIG. 1 is a plan view showing a partial cross-section of a first embodiment of an electric discharge machining apparatus according to the present invention.

FIG. 2 is a plan view showing a partial cross section as viewed in the vertical direction in FIG.

FIG. 3A is a side view showing a part of a cross section of the electrode according to the second embodiment, and FIG. 3B is a cross sectional view taken along the line AA of FIG.

4A is a side view showing another example of the electrode in FIG. 3 in a partial cross section, and FIG. 4B is a cross sectional view taken along the line BB of FIG.

FIG. 5 is a schematic configuration diagram showing a first example of a conventional electric discharge machine.

FIG. 6 is a schematic configuration diagram showing a second example of a conventional electric discharge machine.

[Explanation of symbols]

1 ... Water tank, 2 ... Processing liquid, 3 ... Workpiece, 4 ... Pedestal, 5 ...
Electrodes, 6 ... Driving unit, 7 ... Control unit, 8 ... Hole, 9 ... Cylindrical body,
10 ... Control cable, 11 ... Workpiece, 12 ... Through hole, 13 ... Chip collection hole, 14 ... First housing, 15 ... Second housing, 16 ... Insulation seal, 17 ... O-ring, 18a, 18b ， 18
c ... Electrode (present invention), 19 ... Electrode insertion hole, 20 ... Drain pipe, 21
... Drainage port, 22 ... Drainage nozzle, 23 ... First plate, 24 ...
Guide rod, 25 ... Second plate, 26 ... Drive unit, 27 ...
Electrode rotation motor, 28 ... ball screw, 29 ... gear, 30 ... servo motor, 31 ... control cable, 32 ... jet nozzle, 33 ...
Machining liquid flow path, 34 ... Water supply nozzle, 35 ... Water supply pipe, 36 ... Vacuum unit, 37 ... Air piping, 38 ... Drainage main piping, 39 ...
Contact, 40 ... Spring, 41 ... Negative terminal, 42 ... Positive terminal, 43 ... Lead wire, 44 ... Grooved part, 45 ... Arc surface, 46
… Tapered surface.

Claims (3)

[Claims] 1. A pair of housings, one end of which is closed and the other end of which is open, locally seals a portion to be punched in a workpiece, and an insulating seal is provided inside the opening of the workpiece and the housing. , Insert the electrode through this insulating seal, contact the tip of this electrode with the workpiece, connect the other end of this electrode to the electrode rotation motor, and use this electrode rotation motor as the drive unit. Attach the ball screw to this drive unit, attach this ball screw to the servomotor via the gear, and direct it toward the machining fluid flow path and the workpiece to flow the machining fluid into the electrode. An electric discharge machine comprising a jet nozzle for jetting. 2. The electric discharge machine according to claim 1, wherein a drainage port for the machining fluid is provided in the insulating seal, and the drainage port is connected to a vacuum unit by air supply. 3. The electrode has an arcuate surface or a tapered surface formed at a tip end thereof, a plurality of grooves formed on an outer peripheral surface thereof, and a machining liquid jetting passage formed at a center end in the axial direction of the electrode. The electric discharge machine according to claim 1, wherein: