JPH06190633A - Electric discharge machining device - Google Patents

Abstract

PURPOSE:To secure a clear image of a machining part through a hood and the like of an image pickup device, which is housed inside a cylindrical body, and to visually observe the condition of electric discharge machining by jetting a fresh and transparent working fluid toward a machining part from an opening part for picking up an image in the cylindrical body. CONSTITUTION:When electric discharge machining is carried out, a voltage pulse is impressed between an electrode 3 and a work piece 28 from a power source circuit. A machining part of the work piece 28 and an outer circumferential outline part of a working distance are irradiated by plural irradiating devices 24, 25 installed in plural image pickup devices 22, 23. The photographed result is displayed in a display device 36 while the irradiated part is photographed by plural image pickup devices 22, 23. A fresh and transparent working fluid is jetted continuously from each of opening parts 26a, 27a for image pickup in each of plural cylindrical bodies 26, 27. In this way, the working fluid contaminated by working dust around the machining part is eliminated from at least each of the opening parts 26a, 27a, so that a clear image of the machining part is observed through plural hoods 22a, 23a housed inside the cylindrical body.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric discharge machine.

[0002]

2. Description of the Related Art An electric discharge machining apparatus is different from ordinary machining in which mechanical force is directly applied to a work piece so that the work piece and the electrode are opposed to each other with a slight gap therebetween, and the machining liquid is placed in the gap. Voltage is applied between the two,
It is a non-contact machining that utilizes the electric discharge erosion phenomenon that occurs at that time.

When performing electric discharge machining, the material of the electrode is selected in consideration of the purpose and conditions of machining, the material of the workpiece, and the like.
Furthermore, in consideration of the required surface roughness, electrode consumption ratio, processing speed, etc., the processing conditions suitable for the purpose of the shape of the workpiece or the product, that is, the duration of the power supply voltage, voltage pulse or discharge current pulse. The time, the rest time, the amplitude of the discharge current, the hydraulic pressure of the working liquid, the supply method, and the like are selected and set to perform the working. Thus, when the electric discharge machining is carried out favorably, the electric discharge is distributed substantially evenly over the machining gap between the electrode and the workpiece, but the distance between the workpiece and the electrode is predetermined. If it is not maintained at the value of, or if the amount and properties of the machining liquid intervening in the machining gap fluctuate, the discharge in the machining gap between the electrode and the workpiece becomes irregular, and it is even over the machining gap. The electric discharge between the electrode and the workpiece is concentrated in one place, and this is transferred to an abnormal electric discharge such as an arc.

As described above, when the electric discharge is not normally performed, the machining speed is lowered, and further, the machining performance such as the consumption of the electrode and the roughness of the machined surface is deteriorated so that the machining cannot be smoothly carried out. Depending on the situation, the expensive electrode or the work piece may be damaged. Thus, conventionally, the state of discharge or the quality thereof has been determined by measuring the discharge voltage or the discharge current, but this determination is difficult. In particular, when harmful discharge occurs, discharge concentrates prior to it, but it was difficult to detect early occurrence of the precursory concentrate discharge.

In order to solve such a problem, the present inventor has previously disclosed in Japanese Patent Application No. 59-183672 that a portion to be machined of a workpiece opposed to an electrode during electric discharge machining or a machining formed by both of them. The outer peripheral contour line portion of the gap is enlarged or reduced to be displayed on the display device, and the discharge state of the outer peripheral contour line portion of the machining portion or the machining gap is discriminated by the naked eye or an appropriate automatic discriminating device to discriminate between the electrode and the workpiece. If the discharge between them becomes irregular more than a certain allowable value, or if it is no longer performed in a state where they are appropriately dispersed in the machining gap, or the color tone or spectrum of each individual discharge changes more than a predetermined amount, or a characteristic color tone or spectrum etc. When detected, immediately control each part of the device and adjust so that normal discharge is performed, and it is possible to prevent damage to the electrode and work piece etc. due to abnormal discharge etc. It disclosed the engineering equipment.

That is, the gist of the invention disclosed in Japanese Patent Application No. 59-183672 is that, in an electric discharge machine, a machined portion of a workpiece facing an electrode during electric discharge machining, particularly both of them. A light source for irradiating a desired portion of the outer peripheral contour line of the machining gap formed by the image pickup device, an image pickup device for photographing the portion and the desired outer peripheral contour line portion of the processing gap, and a display device for displaying a signal from the image pickup device on the screen. This makes it possible to clearly project the machining part of the workpiece facing the electrode and the desired outer contour line of the machining gap on the screen of the display device during the electric discharge machining, and the distribution state of the discharge, gas and machining. Abnormal discharge such as concentrated discharge or arc discharge or its pre-development or by detecting the state of generation of dust, or further, the color tone or spectrum of discharge by normal or appropriate detection with naked eyes or appropriate equipment. Together immediately discover driving state or the like, such expensive electrode or the workpiece was intended to prevent from being damaged by the abnormal discharge.

[0007]

Therefore, even in the electric discharge machine equipped with the image pickup device and the display device as described above, the machining liquid near the machined portion is caused by machining chips or gas generated during machining. There was a problem that clear images could not be obtained when it became dirty. The present invention has been made to solve the above problems, and an object of the present invention is to provide an electric discharge machining apparatus configured to obtain a good and clear image regardless of contamination of a machining fluid. It is in.

[0008]

[Means for Solving the Problems] The above object is
Electric discharge machining is performed in the electric discharge machining device that supplies machining fluid between the work piece and the electrode and applies a voltage pulse of a predetermined value from the power supply circuit between them to generate electric discharge A light source for irradiating the outer peripheral contour line portion of a machining gap formed by the machined portion of the workpiece or the both of which is sometimes opposed to the electrode, an imaging device for photographing the machining or contour line portion, and an opening for photographing Then, at least a cylindrical body for accommodating the lens holding cylinder or the hood of the image pickup device, a device for supplying a clean working liquid between the cylindrical body and the lens holding cylinder or the hood, and an image by reproducing a signal from the image pickup device. This is achieved by providing a display device for displaying the image on the screen.

[0009]

With the above structure, a fresh and transparent processing liquid is ejected from the photographing opening of the cylindrical body toward the processed portion, whereby the lens holding cylinder of the image pickup device housed in the cylindrical body. Alternatively, a clear image of the processed portion is formed in the imaging device through the hood.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below with reference to the embodiments shown in the drawings. 1 is an explanatory view showing an embodiment of an electric discharge machine according to the present invention, FIG. 2 is an enlarged explanatory view of an image pickup device portion thereof, and FIG. 3 is another embodiment of an electric discharge machine according to the present invention. It is an explanatory view shown.

First, FIGS. 1 and 2 will be described. In FIGS. 1 and 2, 1 is a processing machine main body of an electric discharge machining apparatus, 2 is a processing bed provided on a column standing on a head or the like so as to be capable of vertical feed positioning or feed control, 3 is an electrode, 4 is a cylindrical shape Alternatively, a processing tank formed in a shape similar to this, 5 is a rail mounted on the outer peripheral wall surface of the processing tank 4, 6 and 7 are traveling carriages traveling on the rail 5,
Reference numerals 8 and 9 denote motors attached to the respective traveling carriages 6 and 7, 10 and 11 denote drive wheels attached to shafts 8a and 9a of the respective motors 8 and 9, and 12 and 13 denote respective traveling carriages 6 and 7. Auxiliary wheels rotatably supported by arms 6a and 7a formed in
And 17 are support arms attached to the respective traveling carriages 6 and 7, 18 and 19 are thumbscrews, and 20 and 21 are attached to the respective support arms 16 and 17 so that their vertical positions can be adjusted, and their tips are provided. Rods having image pickup devices 22 and 23 attached thereto, 22a and 23a are lens holding cylinders or hoods of the image pickup devices 22 and 23 (hereinafter simply referred to as "hoods"), and 24 and 25 are light sources such as laser oscillators, and hoods. Devices attached to the tips of 22a and 23a for irradiating the processed part with strong light, and 26 and 27 are hoods 22a of the image pickup device.
And a cylindrical body provided so as to house 23a in a surrounding form, 28 is a workpiece housed in the processing tank 4,
29 and 30 are cross slide tables that move the processing tank 4 in the X-axis and Y-axis directions, 31 is a turntable that is mounted on the cross slide table 29 and imparts rotational motion to the processing tank 4, and 32 is a cross slide table 29 and Base on the head of the electric discharge machine body 1 on which 30 is mounted, 33, 34
Reference numerals 35 and 35 are motors for driving the cross slide tables 29, 30 and the turntable 31, and 36 is a display device. Thus, the workpiece 28 is housed in the processing tank 4 and the turntable 31 on which the processing tank 4 is mounted is mounted.
And, the cross slide tables 29, 30 provide a rotary motion and a machining feed motion in the X-axis and Y-axis directions.

The processing tank 4 is formed in a circular shape or a similar shape, and a rail 5 is mounted on the outer peripheral wall surface of the processing tank 4, and traveling carriages 6 and 7 moving on the rail 5 are mounted on the rail 5. . A motor 8 is mounted on the traveling carriages 6 and 7.
And 9 are attached, the guide wheels 14 and 15 of the traveling carriages 6 and 7 ride on the upper surface of the rail 5, and drive wheels 10 and
11 and auxiliary wheels 12 and 13 sandwich the rail 5 from both sides,
The traveling vehicles 6 and 7 travel on the rail 5 as the motors 8 and 9 rotate.

A support arm 16 is attached to the traveling carriages 6 and 7.
And 17 are attached, and rods 20 and 21 are fixed to the support arms 16 and 17 by thumbscrews 18 and 19. Then, by loosening the thumbscrews 18 and 19, the vertical positions of the rods 20 and 21 can be adjusted. Further, imaging devices 22 and 23 are attached to the tip ends of the rods 20 and 21 so that the position and orientation can be adjusted by appropriate means. The operation of each unit is configured to be collectively controlled by a numerical controller (not shown) according to a predetermined program.

Thus, the imaging devices 22 and 23 and the irradiation devices 24 and 2
5. Since the cylindrical bodies 26 and 27 have the same structure, only the structure of the image pickup device 22 will be described in detail here with reference to FIG. The hood is attached to the lens mounting opening 22b of the image pickup device 22.
A glass plate 22c is attached in a watertight manner inside the hood tip so as to prevent the working fluid from entering. Light from a separately provided light source such as laser light or halogen light is introduced into the outer peripheral wall surface of the hood tip through an optical fiber or the like, and the light is applied to the workpiece 28.
An irradiating device 24 for irradiating the outer peripheral contour line portion of the machining gap formed by facing the electrode 3 and the electrode 3 is attached.
Further, during processing, the processing liquid supply pipe 26 provided on the side wall of the cylindrical body 26
A clean working fluid is introduced into the cylindrical body 26 through a hose 26c connected to b, and the working fluid is ejected from the opening 26a, which also serves as an opening for photographing, of the cylindrical body 26 toward the working portion.

When machining is performed by the electric discharge machining apparatus according to the present invention, a predetermined voltage pulse is applied between the electrode 3 and the workpiece 28 from a power supply circuit (not shown). When the electric discharge machining is started, the pre-positioned image pickup devices 22 and 23 and the display device 36 are activated, or if necessary, along the desired local portion of the outer peripheral contour line portion of the machining gap, or along the contour line portion. In order to perform continuous detection, two traveling carriages 6 and 7 start traveling at a predetermined speed toward a certain direction or position on a rail 5 mounted on the outer peripheral wall surface of the processing tank 4. In any case, the irradiation devices 24 and 25 attached to the outer peripheral wall surfaces at the tips of the imaging devices 22 and 23 irradiate the desired processed portion of the workpiece 28 and the peripheral contour line portion of the processing gap, and the processed portion. Image capturing devices 22 and 23 The shadow is cast and the signal is sent to the display device 36 and displayed on the screen of the display device 36.

Thus, during electric discharge machining, the machined portion of the body to be machined 28 and the outer peripheral contour line portion of the machining gap are irradiated by the irradiation devices 24 and 25, and the openings 26a for photographing of the cylindrical bodies 26 and 27 are formed. Fresh and transparent working fluid is continuously ejected from 27a. Therefore, the processing liquid near the processed portion, which is contaminated by processing waste, is pushed away at least from the front of the openings 26a and 27a, and the hood 22 housed in the cylindrical body is removed.
A clear image of the processed part can be observed through a and 23a.

Therefore, the image pickup devices 22 and 23 can clearly display the image of the desired processed portion of the work piece 28 on the screen of the display device 36 even if the processing liquid near the processed portion is polluted by processing wastes. it can. Then, when electric discharge is not performed uniformly or abnormal electric discharge such as arc occurs in a state where the electric discharge is substantially evenly distributed in the machining gap between the electrode 3 and the workpiece 28 during machining, this is visually detected. It is possible to return to a favorable discharge state by controlling each part of the device immediately after detection and determination by automatic detection. The imaging devices 22 and 23
It is desirable to use an oil resistant structure. Further, it is desirable that the display device 36 is capable of enlarging or reducing the image as needed.

Next, referring to FIG. 3, an embodiment in which the present invention is applied to a wire-cut type electric discharge machine will be described. In FIG. 3, the elements having the same numbers as those shown in FIGS. 1 and 2 indicate the same components as those shown in FIGS. 1 and 2, and 37 is a processing head. Nozzle device attached to the upper arm 38 attached to a column or the like instead of 2, 39 is a nozzle holder, 40 is a nozzle, 41 is a cap nut, 42 is a die fixed to the guide holder 43, 44 and 45 Is a power supply pin, 46 is a spring, 47 is a rubber valve, 48 is a machining fluid supply hole, 49 is a brake roller / capstan which acts as a brake when the motor is stopped, 50 and 51 are pinch rollers, 52 Is capstan,
53 is a wire electrode.

Thus, the nozzle holder 39 is a mounting flange.
The nozzle 40 has a nozzle chamber 39a and a nozzle chamber 39b. A nozzle 40 is slidably fitted in the nozzle holder 39, and a spring 46 and a cap nut 41 are sequentially attached. After that, this nozzle device
37 is attached to the upper arm 38 by a mounting flange 39a and a mounting bolt (not shown).

The wire electrode 53 is supplied from an electrode supply device (not shown), passes between the brake roller / capstan 49 and the pinch roller 50, and is supplied to the workpiece 28 by the power supply pins 44 and 45 in the nozzle holder 39. A predetermined voltage pulse is supplied during this period, and is passed through the die 42, between the pinch roller 51 and the capstan 52, and is recovered by an electrode recovery device (not shown). Between the wire electrode 53 and the workpiece 28, a pulse width from a power supply device (not shown),
Electric discharge machining is performed by applying a voltage pulse whose discharge current amplitude or voltage pulse interval is controlled to a predetermined value.

When the electric discharge machining is started, the image pickup devices 22 and 23 and the display device, which have been set in advance, are set.
A rail mounted on the outer peripheral wall surface of the processing tank 4 in order to activate the 36 or, if necessary, to continuously detect along a desired local portion of the outer peripheral contour portion of the machining gap or along the contour portion. Two traveling carriages 6 and 7 start traveling at a predetermined speed toward a certain direction or position on the hood 5, and the hoods 22a attached to the imaging devices 22 and 23 and
Irradiation devices 24 and 25 attached to the tip end portion of 23a irradiate the machining gap portion between the wire electrode 53 and the workpiece 28, and an opening portion 26 for photographing the tip end of the cylindrical bodies 26 and 27.
The machining fluid contaminated by the clear machining fluid ejected from a and 27a is removed, and therefore, the photographing devices 22 and 23 photograph a clear image of the machining gap portion, and the video signal is sent to the display device 36. Display device 36
Is clearly displayed on the screen.

[0022]

Since the present invention is constructed as described above, according to the present invention, the processed portion of the workpiece facing the electrode during the electric discharge machining, the desired outer peripheral contour line portion of the machining gap formed by the two or The machining gap between the wire electrode and the workpiece is clearly projected on the screen of the display device regardless of the contamination of the machining liquid due to the machining, and the discharge state, the color tone of the discharge, the spectrum, etc. are constantly or at an appropriate time visually. Alternatively, since it is possible to perform processing while detecting and discriminating with an appropriate device, abnormal discharge such as concentrated discharge or arc discharge can be prevented in advance, and an expensive electrode or a work piece is damaged by the abnormal discharge. Can be prevented.

The present invention is not limited to the above embodiment. That is, for example, the number of traveling carriages is two in the present embodiment, but the number of traveling carriages can be appropriately increased or decreased according to the size and processed shape of the workpiece. Further, the irradiation device is provided at the tip portion of the imaging device, but it may be provided at the tip of the cylindrical body or may be provided entirely separately, and the light source of the irradiation device is not limited to the laser oscillator or the halogen lamp, and the workpiece is Other known light sources can be used as long as they can sufficiently irradiate the processed portion and the outer peripheral contour line portion of the processing gap. Further, although the observation with the naked eye is mainly described, the output signal of the image pickup apparatus is repeatedly updated while being temporarily recorded, and an appropriate device is used to determine whether or not the output signal is uniformly distributed over the entire discharge surface, for example. It is recommended that the configuration be such that detection and discrimination is performed using a device, and other methods such as the mounting method of the image pickup device, the display method thereof, and the control method of each unit can be freely designed within the scope of the present invention. Therefore, the present invention includes all of them.

[Brief description of drawings]

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

FIG. 2 is an enlarged explanatory view of the image pickup device section.

FIG. 3 is an explanatory view showing another embodiment of the electric discharge machine according to the present invention.

[Explanation of symbols]

 1 ・ ・ ・ ・ ・ ・ Processing machine main body 2 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Processing head 3 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Electrode 4 ・ ・ ・ ・ ・ ・ ・ ・Processing tanks 5 ・ ・ ・ ・ ・ ・ ・ ・ Rails 6, 7 ・ ・ ・ ・ ・ ・ Trucks 8, 9, 33, 34, 35 ・ ・ Motors 10, 11 ・ ・ ・Drive wheels 12, 13 ・ ・ ・ ・ ・ ・ Auxiliary wheels 14, 15 ・ ・ ・ ・ ・ ・ Guide wheels 18, 19 ・ ・ ・ ・ ・ ・ Thumbscrews 20, 21 ・ ・ ・・ ・ Rod 22, 23 ・ ・ ・ ・ ・ ・ Imaging device 22a, 23a ・ ・ ・ ・ ・ ・ Hood 24, 25 ・ ・ ・ ・ ・ ・ ・ ・ Irradiation device 26, 27 ・ ・ ・ ・ ・Lens holding tube or hood 26a, 27a ・ ・ ・ ・ ・ ・ Apertures 26b, 27b for photography ・ ・ ・ ・ ・ ・ Processing liquid supply pipe 26c ・ ・ ・ ・ ・ ・ ・ Processing liquid supply hose 28 ・ ・ ・・ ・ ・ ・ ・ ・ ・ Workpiece 29, 30 ・ ・ ・ ・ ・ ・ ・ ・ Cross slide table 31 ・ ・ ・ ・ ・ ・・ ・ ・ ・ Turntable 32 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Base 36 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Display device

Claims (4)

[Claims] 1. A machining liquid is supplied and interposed between a workpiece (28) and an electrode (3), and a voltage pulse having a predetermined value is applied between them to generate an electric discharge, thereby machining. In the electric discharge machining device for performing the electric discharge machining, a light source (24, 25) for irradiating the machining part of the workpiece (28) facing the electrode (3) or the outer peripheral contour line part of the machining gap formed by both of the electrodes (3) at the time of electric discharge machining. ), An imaging device (22, 23) for imaging a processed or contour line portion, and an opening (26a, 27a) for imaging, and at least a lens holding tube or hood (22a, 22a) of the imaging device (22, 23). A cylinder (26, 27) accommodating 23a), and a device for supplying a working fluid between the cylinder (26, 27) and the lens holding cylinder or the hood (22a, 23a),
An electric discharge machine characterized by comprising a display device (36) for reproducing a signal from an image pickup device (22, 23) and displaying an image on a screen. 2. The electric discharge machine according to claim 1, wherein the imaging device (22, 23) is a video camera. 3. The electric discharge machine according to claim 1, wherein the imaging device (22, 23) is an image sensor. 4. The electric discharge machine according to claim 1, wherein the display device (36) has a function of enlarging or reducing an image.