JP4152515B2 - Ultra fine electrical discharge machine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an ultra-fine electric discharge machine mainly used for machining fine holes and fine slits by utilizing discharge generated in a fine discharge gap between a miniaturized discharge electrode and a workpiece. It is.
[0002]
[Prior art]
Conventionally, micro electric discharge machining technology has been mainly used as a micro hole machining method, including nozzle hole machining for inkjet printers. In recent years, an ultra fine electric discharge machine capable of machining holes up to a minimum of 5 μm. Has been developed. Such an ultra fine electric discharge machine has an overall configuration as shown in the configuration diagram of FIG. This ultra-fine electric discharge machine includes a machining head portion 1 that moves with a fine electric discharge electrode 2 attached thereto, a positioning mechanism portion 4 that positions a workpiece 3, and wire electric discharge grinding that forms the electric discharge electrode 2 into an arbitrary shape. The basic configuration is roughly divided into a unit (not shown) and a micro discharge circuit 7 having an NC control unit (not shown).
[0003]
A vertical mandrel 9 is rotatably attached to the machining head 1 via a bearing 8 and is driven to rotate with high accuracy by a DC motor 10. A discharge electrode 2 is attached to the lower end of the mandrel 9. The machining head 1 is moved up and down by the rotation of the ball screw 11. Further, the positioning mechanism unit 4 has a configuration in which a processing table 13 on which the workpiece 3 is placed in a positioning state is installed inside the processing tank 12. The micro discharge circuit 7 includes a central processing unit 14, a power supply unit 18 that applies a pulse voltage between the discharge electrode 2 and the workpiece 3 via a capacitor switch 17 under the control of the central processing unit 14, A motor drive control circuit 19 that controls the rotation of the DC motor 10 with high accuracy under the control of the processing unit 14 is provided. As shown in the drawing and the cut plan view of FIG. 5B, a machining liquid supply unit 21 that discharges pure water, which is an electrically insulating liquid, from the discharge nozzle 21a as an electric discharge machining liquid 20, covers the discharge nozzle 21a. The workpiece 3 is attached to the machining table 13 via a support member 22 in an arrangement toward the electric discharge machining position by the discharge electrode 2. This ultra-fine electric discharge machine is configured such that the electric discharge machining liquid 20 is sprayed from the discharge nozzle 21a of the machining liquid supply unit 21 to the electric discharge machining position, and the electric discharge electrode 2 and the workpiece are interposed via the electric discharge machining liquid 20. 3 is applied with a voltage from the power supply unit 18 and the discharge is generated when the discharge electrode 2 is brought close to the workpiece 3 by the lowering of the processing head unit 1 to process a fine hole. It is.
[0004]
This processing proceeds while repeating melting of the workpiece 3 and removal of electric discharge machining waste due to heat generated by electric discharge. Therefore, the discharge is pulsed.
[0005]
This ultra fine electric discharge machine has various major features as follows. That is, by minimizing the discharge energy and miniaturizing the discharge electrode 2, it is possible to perform micro electric discharge machining, and any material 3 can be processed as long as it has conductivity, Even the workpiece 3 made of a material having high hardness can be easily processed. Further, it is possible to process a material having a high specific resistance such as silicon ferrite, which has a problem such as cracking in normal electric discharge machining, and also provides a processing force to the workpiece 3 because it is non-contact machining. It can be processed without any problem, and can be processed with high precision into curved surfaces, inclined surfaces, thin plates, etc., which are difficult by drilling. Furthermore, if the hole diameter is 50 μm or more, it is possible to process a hole having a depth 10 times that of the hole. Therefore, the hole diameter can be suitably applied to processing of a mold used for plastic processing such as punching of micro mechanical parts. It has various big features such as.
[0006]
[Problems to be solved by the invention]
However, in the conventional ultra-fine electric discharge machine, as shown in FIG. 5, since the electric discharge machining liquid 20 is supplied in such a manner that the electric discharge machining liquid 20 is directly sprayed and dripped onto the electric discharge machining position of the workpiece 3, the machining liquid supply is performed. Since the electric discharge machining fluid 20 ejected from the discharge nozzle 21a of the section 21 is not streamlined due to the surface tension, as shown in the plan view of FIG. As shown in the cross-sectional view of FIG. 7, bubbles 24 are generated as the electric discharge machining waste 23 rises by electric discharge. In such a case, the discharge phenomenon does not always occur in the electric discharge machining liquid 20 that is an electrical insulator, resulting in a discharge phenomenon in the air, so that the processed surface of the workpiece 3 is roughened. In addition to the above-described processing failure, the air between the discharge electrode 2 and the workpiece 3 may cause an inconvenience that the discharge phenomenon is interrupted and the processing stops.
[0007]
Further, in order to prevent the above-described discharge phenomenon in the air, a machining liquid layer is formed by the electric discharge machining liquid 20, and the discharge gap G between the workpiece 3 and the discharge electrode 2 is formed in the machining liquid layer. Therefore, a large amount of electric discharge machining liquid 20 which is expensive pure water is required and the running cost is high, and a storage tank for storing a large amount of used electric discharge machining liquid 20 is required. As a result, the overall size of the apparatus increases and the cost increases. In addition, as the flow rate of the electric discharge machining fluid 20 increases, the fine electric discharge electrode 2 is vibrated and cannot be processed with high accuracy, or the electric discharge electrode 2 may be damaged. is there. Further, as clearly shown in FIG. 7, the machining liquid layer formed by the electric discharge machining liquid 20 sprayed in a large amount forms a thick stagnation including the electric discharge machining waste 23, and the electric discharge machining swarf 23 becomes the discharge electrode in the stagnation. If it adheres to 2, the electric discharge will generate | occur | produce in the wide range exceeding a predetermined range, and the process defect may arise in the workpiece 3 resulting from this.
[0008]
In addition, since the machining liquid supply unit 21 is rotatably attached to the machining table 13, the machining liquid supply unit 21 is provided each time a difference in the thickness of the workpiece 3 or the movement of the machining position is performed. The direction of the discharge nozzle 21a must be adjusted by turning.
[0009]
Therefore, the present invention has been made in view of the above-described conventional problems, and is capable of always reliably covering the discharge gap between the discharge electrode and the workpiece with an electric discharge machining liquid having a flow rate as small as possible. An object of the present invention is to provide an ultra-fine electric discharge machine having a configuration capable of forming a liquid layer.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, in the ultra-fine electric discharge machine of the present invention, a voltage is applied to a workpiece that is horizontally mounted on a machining table surface via an electric discharge machining fluid, and the workpiece is applied to the workpiece. A discharge electrode that generates a machining discharge due to the proximity of the discharge electrode and concentrated around the discharge electrode to ensure a discharge gap between the tip of the discharge electrode and the discharge machining position of the workpiece. In order to form a thin working fluid layer that can be covered, a machining fluid supply unit that continuously supplies the electrical discharge machining fluid from a discharge nozzle in a necessary minimum amount, and the used electrical discharge machining in the machining fluid layer A machining liquid recovery unit that absorbs and recovers the liquid from the liquid absorption nozzle together with the electric discharge machining waste, and the machining liquid supply unit and the machining liquid recovery unit include a discharge direction of each of the discharge nozzles and a liquid absorption nozzle. The liquid absorption direction is the workpiece. The intersection at the processing position by the discharge electrodes, and by said discharge nozzle and said liquid absorbing nozzle is provided in an arrangement opposed in proximity on the same line with each other, said supplied from the machining fluid supply unit discharge machining After the liquid is used in the machining discharge, the machining liquid recovery unit absorbs and collects the liquid supplied from the machining liquid supply unit, and reaches the liquid suction nozzle from the discharge nozzle. It is characterized in that it is recovered by the machining fluid recovery unit without deviating from a certain flow path.
[0011]
In this ultra-fine electric discharge machine, the electric discharge machining liquid does not deviate from a constant flow path from the discharge nozzle of the machining liquid supply unit arranged so as to face each other in close proximity to the liquid absorption nozzle of the machining liquid recovery unit. In order to flow stably, the streamline of the electric discharge machining fluid is always stable. And the electric discharge machining liquid that is continuously supplied in a minimum amount is concentrated around the discharge electrode, and it is a thin process that can always reliably cover the discharge gap between the workpiece and the discharge electrode. to form a liquid layer. As a result, it is possible to reliably prevent the occurrence of an electric discharge phenomenon in the air, and it is possible to always perform highly accurate micro electric discharge machining. Moreover, since the EDM, which is generally expensive, can be used very effectively while supplying only the necessary minimum, the running cost can be greatly reduced, and the conventional EDM can be stored. No storage tank is required. In addition, since the flow rate of the electric discharge machining liquid is very small, the fine electric discharge electrode never oscillates due to the influence of the electric flow of the electric discharge machining liquid, so that highly accurate electric discharge machining is always performed stably. Thus, troubles such as breakage of the discharge electrode do not occur.
[0012]
Moreover, since the electric discharge machining waste generated by the electric discharge machining is absorbed by the liquid absorption nozzle of the machining liquid recovery part immediately after the occurrence, the phenomenon that the electric discharge machining waste is caused by the electric discharge as in the case of a conventional processing machine does not occur. Also, there will be no occurrence of a large amount of bubbles. In addition, since the electrical discharge machining fluid is supplied in small amounts to form a thin machining fluid layer, there is no occurrence of a state in which the machining fluid layer forms a thick stagnation including electrical discharge machining waste as in conventional processing machines. Since the processing waste hardly adheres to the discharge electrode, it is possible to reliably prevent discharge in a wide range exceeding a predetermined range, which has been generated in the case of a conventional processing machine.
[0013]
In the above invention, it is preferable that the machining fluid supply unit and the machining fluid recovery unit are supported by the discharge electrode mounting member via a support member.
[0014]
As a result, the machining fluid supply unit, the machining fluid recovery unit, and the discharge electrode always move together while maintaining a predetermined relative position, so that the difference in the thickness of the workpiece, the progress of machining, or the machining position Even when moving, a suitable positional relationship is always automatically maintained. As a result, electrical discharge machining fluid is always sprayed to the required location in any situation, so it is possible to reliably prevent the occurrence of discharge phenomenon in the air, and machining defects such as rough machining of the workpiece. Does not occur.
[0015]
Moreover, in the said invention, it is preferable to use the pure water which is a perfect electric insulation liquid as an electric discharge machining liquid.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a side view showing an outline of a main part of an ultrafine electric discharge machine according to an embodiment of the present invention, and FIG. 2 is a plan view thereof. In this ultra-fine electric discharge machine, each of a machining liquid supply unit 27 that supplies pure water as the electric discharge machining liquid 20 and a machining liquid collection unit 28 that collects the used electric discharge machining liquid 20 while absorbing the liquid. The discharge nozzle 27a and the liquid suction nozzle 28a are supported in a suspended form on the mandrel 9 via support members 29 and 30 in an inclined state toward the electric discharge machining position of the workpiece 3 respectively. Other configurations are the same as the existing ones.
[0017]
As clearly shown in FIG. 2, the machining liquid supply unit 27 and the machining liquid collection unit 28 are configured such that the discharge direction of each discharge nozzle 27 a and the liquid suction direction of the liquid suction nozzle 28 a depend on the discharge electrode 2 of the workpiece 3. The discharge nozzle 27a and the liquid absorption nozzle 28a intersect with each other at the processing position, and are supported by the mandrel 9 via the individual support members 29 and 30 in an arrangement where the discharge nozzle 27a and the liquid absorption nozzle 28a face each other as close as possible. As a result, the machining fluid supply unit 27 and the machining fluid recovery unit 28 move up and down integrally with the mandrel 9 while keeping the relative position of the discharge electrode 2 constant.
[0018]
In the ultra-fine electric discharge machine, the electric discharge machining liquid 20 sprayed from the discharge nozzle 27a of the machining liquid supply unit 27 toward the electric discharge machining position of the workpiece 3 is used for electric discharge machining, and then is subjected to electric discharge machining waste. 23 is absorbed and collected by the liquid suction nozzle 28a of the machining liquid collection unit 28 together. The electric discharge machining fluid 20 is absorbed and collected by the machining fluid recovery unit 28 by the amount supplied from the machining fluid supply unit 27, and discharged from the machining fluid supply unit 27 arranged close to each other on the same line. It flows stably without deviating from a fixed flow path from the nozzle 27a to the liquid suction nozzle 28a of the machining liquid recovery unit 28.
[0019]
For this reason, the electric discharge machining liquid 20 is always sprayed at a location shifted from the electric discharge machining position in the workpiece 3 because the streamline thereof is always stable.
[0020]
As described above, the electric discharge machining liquid 20 always flows stably without deviating from a constant flow path, so it is only necessary to continuously supply a small amount from the machining liquid supply unit 27. As clearly shown in FIG. 2, the minute amount of the electric discharge machining liquid 20 is concentrated around the discharge electrode 2 and always covers the discharge gap G between the workpiece 3 and the discharge electrode 2 reliably. A thin working fluid layer 20a that can be formed can be formed. Since this thin working fluid layer 20a is always formed at a location covering the discharge gap G between the workpiece 3 and the discharge electrode 2, it is possible to reliably prevent the occurrence of a discharge phenomenon in the air. It is always possible to perform highly accurate micro-EDM. In addition, since the electric discharge machining liquid 20 which is expensive pure water can be used very effectively while supplying the necessary minimum amount by a minute amount, the running cost can be greatly reduced. In addition, there is an advantage that a conventional storage tank for storing the used electric discharge machining liquid 20 is unnecessary.
[0021]
In addition, since the flow rate of the electric discharge machining liquid 20 is very small, the fine electric discharge electrode 2 does not vibrate under the influence of the flow of the electric discharge machining liquid 20 at all. Thereby, it is further certain that high-precision fine electrical discharge machining is always performed stably, and troubles such as breakage of the discharge electrode 2 do not occur.
[0022]
FIG. 3 is a process diagram sequentially showing the process of processing microholes in the workpiece 3 by the above-described ultrafine electrical discharge machine. FIG. 3 (a) shows the discharge caused by the proximity of the descending discharge electrode 2 to the workpiece 3. FIG. The state which generate | occur | produced and the process of the micropore was started is shown. (B) and (c) show the progress of the micro hole processing in sequence, (d) shows the processing completion state of the micro hole 31, and (e) shows the state where the discharge electrode 2 is raised after the processing is completed.
[0023]
As shown in the figure, since the electric discharge machining waste 23 generated by the electric discharge machining is absorbed by the liquid absorption nozzle 28a of the machining liquid recovery unit 28 immediately after the occurrence, the electric discharge machining waste 23 rises by electric discharge as in the case of a conventional machining machine. Such a phenomenon does not occur, and a large amount of bubbles 24 associated therewith does not occur. Further, since the electric discharge machining liquid 20 is supplied in small amounts to form a thin machining liquid layer 20a, there is a situation in which the machining liquid layer 20a includes the electric discharge machining waste 23 and forms a thick stagnation as in a conventional machining machine. Therefore, since the electric discharge machining waste 23 hardly adheres to the discharge electrode 2, it is possible to reliably prevent electric discharge in a wide range exceeding a predetermined range, which has been generated in the case of a conventional processing machine.
[0024]
In addition, the machining fluid supply unit 27, the machining fluid recovery unit 28, and the discharge electrode 2 move up and down integrally while always maintaining a predetermined relative position. Therefore, the thickness difference of the workpiece 3 and the progress of the machining are determined. Alternatively, a suitable positional relationship is always automatically maintained when the machining position is moved. For this reason, the electric discharge machining liquid 20 is always reliably sprayed to a required portion in any situation, so that the occurrence of a discharge phenomenon in the air can be reliably prevented. Therefore, processing defects such as roughening of the processing surface of the workpiece 3 do not occur.
[0025]
【The invention's effect】
As described above, according to the ultrafine electric discharge machine of the present invention, the electric discharge machining liquid is constant from the discharge nozzle of the machining liquid supply unit arranged close to the same line to the liquid absorption nozzle of the machining liquid recovery unit. Because it is configured to flow stably without deviating from the flow path, it is possible to concentrate the electrical discharge machining fluid around the discharge electrode and to ensure that the discharge gap between the workpiece and the discharge electrode is always covered reliably. A liquid layer can be formed, it is possible to reliably prevent the occurrence of electric discharge phenomenon in the air and always perform highly accurate fine electric discharge machining, and save expensive pure water as much as possible. The cost can be greatly reduced, and a storage tank for storing the used electric discharge machining liquid becomes unnecessary.
[0026]
Moreover, since the fine discharge electrode never oscillates under the influence of the flow of the electric discharge machining liquid, it is further certain that high-precision fine electric discharge machining is always performed stably, and troubles such as breakage of the discharge electrode can be avoided. It does not occur. In addition, since the EDM waste generated by EDM is absorbed by the liquid absorption nozzle of the machining fluid recovery section immediately after the occurrence, there is no occurrence of soaring of EDM waste or the generation of a large amount of bubbles. It is possible to reliably prevent discharge in a wide range exceeding a predetermined range due to adhesion to the discharge electrode.
[Brief description of the drawings]
FIG. 1 is a side view showing a schematic configuration of a main part of an ultrafine electric discharge machine according to an embodiment of the present invention.
FIG. 2 is a sectional plan view of the processing machine.
FIG. 3 is a process diagram sequentially illustrating a process of processing a microhole in a workpiece by the processing machine same as above.
FIG. 4 is a configuration diagram showing the overall configuration of an ultra-fine electric discharge machine.
FIGS. 5A and 5B show a conventional ultra-fine electric discharge machine, in which FIG. 5A is a partial side view, and FIG.
FIG. 6 is a plan view showing a state in which the electric discharge machining liquid is sprayed on a position shifted from the electric discharge machining position of the workpiece in the ultra-fine electric discharge machine.
FIG. 7 is a cross-sectional view showing a state in which bubbles are generated and electric discharge machining waste adheres to the discharge electrode in the ultra fine electric discharge machine.
[Explanation of symbols]
2 Discharge electrode 3 Work material 9 Mandrel (mounting member)
DESCRIPTION OF SYMBOLS 20 Electric discharge machining liquid 20a Processing liquid layer 27 Processing liquid supply part 27a Discharge nozzle 28 Processing liquid collection | recovery part 28a Liquid absorption nozzles 29 and 30 Support member G Discharge gap

Claims (3)

A voltage is applied between the workpiece horizontally mounted on the machining table surface via the electric discharge machining liquid, and a discharge electrode that generates a machining discharge by proximity to the workpiece;
In order to intensively gather around the discharge electrode to form a thin working fluid layer that can always reliably cover the discharge gap between the tip of the discharge electrode and the discharge machining position of the workpiece A machining fluid supply unit that continuously supplies the electrical discharge machining fluid from the discharge nozzle in a necessary minimum amount;
A machining fluid recovery part that absorbs and recovers the used electrical discharge machining fluid in the machining fluid layer from a liquid suction nozzle together with electric discharge machining waste;
The processing liquid supply unit and the processing liquid recovery unit have a discharge direction of each discharge nozzle and a liquid absorption direction of the liquid absorption nozzle intersect at a processing position of the workpiece by the discharge electrode, and the discharge nozzle. And the liquid absorption nozzle are provided in an arrangement close to each other on the same line and facing each other, so that the electric discharge machining liquid supplied from the machining liquid supply unit is used in the electric discharge for the machining The machining fluid recovery unit absorbs and recovers the amount supplied from the machining fluid supply unit, and does not deviate from a constant flow path from the discharge nozzle to the liquid suction nozzle. An ultra-fine electrical discharge machine characterized by being collected in   The ultrafine electric discharge machine according to claim 1, wherein the machining liquid supply unit and the machining liquid recovery unit are supported by a mounting member of the discharge electrode via a support member.   The ultrafine electric discharge machine according to claim 1 or 2, wherein pure water is used as the electric discharge machining liquid.

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