JPH08118157A - Electric discharge machine - Google Patents

Abstract

PURPOSE: To allow a hole, having an axis intersecting the longitudinal direction of an electrode, to be machined in machined material by providing a hollow connecting part, having a curved axis substantially made a tangent, between both guide parts, and providing a bar electrode movably in the longitudinal direction through the guide parts and the connecting part. CONSTITUTION: When a head is lowered at the specified feed speed, bar electrodes 7 are smoothly guided from the vertical state with the axes thereof placed in the feed direction by guide parts 21, connecting parts 14 and guide parts 22 so as to coincide with the axial direction of machined holes 23 to be machined in machined material 2. Accordingly, plural specified machined holes 23 are simultaneously machined by electric discharge in the machined material 2. After the end of machining, the bar electrodes 7 are moved up, and a table is moved per specified pitch in the orthogonal direction, for instance, through a control device to machine a following row of machined holes 23.

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 for machining a work material by an electric discharge between an electrode and the work material, and more particularly to an axis line intersecting the longitudinal direction of a rod-shaped electrode on the work material. The present invention relates to an electric discharge machine suitable for processing a hole having a hole.

[0002]

2. Description of the Related Art Conventionally, electric discharge machining is capable of machining high hardness materials, which are difficult to machine by cutting, and can be machined to the same contour as the cross section of the tool electrode, so it is used for machining various irregular holes. And has the advantage that high-precision processing is possible.

FIG. 6 is a diagram showing the construction of essential parts of an example of a conventional electric discharge machine. In FIG. 6, reference numeral 51 denotes a bed, and a column 52 is erected on the edge of the bed 51, and a feed mechanism 53 interposed at the upper end of the column 52 moves a holder 55 holding an electrode 54 in the vertical direction. Configure as possible. A processing tank 57 containing a processing liquid 56 is provided on the bed 51,
The material 58 to be processed is placed in the processing tank 57. And electrode 5
4 and the work piece 58 are respectively connected to a working power source (not shown), the feed mechanism 53 lowers the electrode 54, and the working fluid 5
By generating an electric discharge between the electrode 54 and the work material 58 in 6, the work material 58 can be processed into holes, recesses and the like.

[0004]

By using the above-described electric discharge machining, it is possible to machine a hole having a minute diameter of 1 mm or less. In this case, the axis of the hole and the feeding direction of the electrode 54 are aligned. Need to let. Therefore, it is impossible to simultaneously process a plurality of holes having axes intersecting the feed direction of the electrode 54 at different angles.

FIG. 7 is a cross sectional view showing an example of a blade for a gas turbine. In FIG. 7, since the outer surface of the blade 61 is exposed to high temperature gas, the blade 61 is made of a corrosion resistant heat resistant alloy, and has a cavity 62 inside and a cooling hole 63 communicating with the cavity 62 so that the blade 61 is compressed from the cavity 62. Air is ejected to form an air film on the surface of the blade 61.

Since the plurality of cooling holes 63 as described above have their axes not intersecting in the same direction but intersecting each other, when machining these cooling holes 63, the cooling holes 63 must be changed each time. It is necessary to align the axis of the electrode with the feeding direction of the electrode 54 (see FIG. 6). Since 40 to 80 cooling holes 63 are provided in one blade 61, in this case, for example, setup change is required every 20 minutes, and not only automatic operation is naturally impossible, There has been a problem that a great deal of time and man-hours are required for the working work, the working efficiency is lowered, and the working cost is increased.

Next, FIG. 8 is an explanatory view showing the vicinity of the cooling hole 63 in FIG. 7, (a) is an enlarged cross section, and (b) is a view in the direction A in (a). In FIG. 8, 64
Is a concave portion, which is provided on the surface of the blade 61 in the downstream direction of the gas flow in the cooling hole 63. In the case of processing such a concave portion 64, after processing the cooling hole 63, it has to be processed by another electric discharge machine, and there is a problem that processing time and processing man-hour increase.

An object of the present invention is to solve the above problems existing in the prior art and to provide an electric discharge machine suitable for machining a hole having a shaft line intersecting the longitudinal direction of an electrode in a workpiece. And

[0009]

In order to achieve the above object, in the present invention, an electric discharge machine for machining a hole having an axis intersecting with the longitudinal direction of a flexible rod-shaped electrode in a workpiece. In the case of (1), between the electrode head, which holds the rear end of the rod-shaped electrode and is movable in the longitudinal direction of the rod-shaped electrode, and the table on which the workpiece is placed, the approach portion holder and the guide are provided with a predetermined gap. The guide part holder and the guide part holder are formed integrally with each other, and the guide part holder is penetrated by a hollow guide part having an axis in the moving direction of the rod electrode and the guide part holder in the axial direction of the machining hole of the workpiece. And provided with a hollow connecting portion having a curved axis line substantially tangential to the axis between the two guide portions,
A technical means was adopted in which the rod-shaped electrode is configured to be movable in the longitudinal direction via the guide portion and the connecting portion.

In the present invention, the approach portion holder, the guide portion holder and the table can be formed so as to be relatively movable in the direction orthogonal to the moving direction of the rod-shaped electrode.

[0011]

With the above structure, by moving the rod-shaped electrode in the longitudinal direction, the tip of the rod-shaped electrode is guided in the axial direction of the hole to be machined in the workpiece, and the predetermined hole can be electric discharge machined. . Further, by moving the material to be processed in a direction orthogonal to the moving direction of the rod-shaped electrode by NC control, for example, it is possible to discharge the concave portion having a predetermined shape continuously or independently of the hole processing. You can do it.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an explanatory view of the essential structure of an embodiment of the present invention. In FIG. 1, reference numeral 1 is a table, which is placed on a bed (not shown, see reference numeral 51 in FIG. 6) that constitutes an electric discharge machine, and is formed so as to be controllably movable in the XY directions in a horizontal plane, for example. On the table 1, a mounting table 3 for mounting the work piece 2 and a supporting table 4 for supporting an approach portion holder and a guide portion holder, which are formed as will be described later, are mounted via, for example, bolts or other fastening means. Set up.

Next, 5 is a head, which is constructed so as to be movable in the vertical direction by an appropriate feeding mechanism (not shown). An electrode head 6 is provided below the head 5 and holds the rear ends (upper ends) of the plurality of rod-shaped electrodes 7. In addition, the rod-shaped electrode 7 is formed in a hollow tubular shape, and the working liquid is circulated from the working liquid supply portion provided in the electrode head 6 into the rod-shaped electrode 7 so that the working liquid is ejected from the tip (lower end) of the rod-shaped electrode 7. You may comprise.

Reference numeral 8 is an approach portion holder, and 9 is a guide portion holder. The bracket 1 is integrally connected through a connecting member 10 and fixed to one end of the approach portion holder 8, for example.
1 and a linear bearing 12 provided on this bracket, and is vertically movable relative to a guide 13 provided on the lower portion of the head 5. Reference numeral 14 denotes a connecting portion, which is formed in a hollow tubular shape and is provided between the approach portion holder 8 and the guide portion holder 9 so that the rod-shaped electrode 7 can move in the connecting portion 14 in the longitudinal direction.

Reference numeral 15 is a sub-table, and the bracket 1
Supporting table 4 which supports the table 1 and is provided on the table 1.
Then, for example, it is formed so as to be relatively movable in the XY directions. 2 is a partially enlarged cross-sectional explanatory view showing the approach portion holder 8 and the guide portion holder 9 shown in FIG. 1 and the vicinity thereof, and the same portions are denoted by the same reference numerals as those in FIG. In FIG. 2, reference numeral 21 denotes a guide portion, which is formed in the approach portion holder 8 in a hollow shape so as to have an axis in the moving direction of the rod-shaped electrode 7. 22 is a guide part, which is formed in a hollow tubular shape,
The guide portion holder 9 is provided with a processing hole 2 to be provided in the workpiece 2.
It is provided so as to match the axial direction of 3.

The connecting portion 14 is formed in a hollow tubular shape as described above, but its axis is formed in an arc or a curved line with the axis of the guide portions 21 and 22 as a tangent line, and the rod-shaped electrode 7 is bent undesirably. The rod-shaped electrode 7 is formed so that the axis of the rod-shaped electrode 7 can be smoothly changed without a directional force. The axis of the connecting portion 14 is preferably formed in a curved shape with the axis of the guide portions 21 and 22 as a tangent line, but the rod-shaped electrode 7 can be smoothly guided even if the two axes do not completely match. Good.

Therefore, it is sufficient that the axes of the guide portions 21 and 22 are substantially tangent to the curved axis of the connecting portion 14. The inner diameter of the guide portion 22 is 0.02 to 0.05 mm larger than the outer diameter of the rod electrode 7 (for example, 1 mm), and the inner diameter of the guide portion 21 and the connecting portion 14 is larger than the outer diameter of the rod electrode 7.
The size is preferably 0.1 to 0.15 mm. Alternatively, the guide portion 21 and the connecting portion 14 may be separately formed so as to communicate with each other in the approach portion holder 8.

With the above structure, the workpiece 2 is positioned and fixed on the mounting table 3 as shown in FIG. 1, and a working liquid is supplied between the rod-shaped electrode 7 and the workpiece 2 (or the workpiece is processed). The head 5 is lowered at a predetermined feeding speed while the material 2 is immersed in the working liquid. Then, as shown in FIG. 2, the rod-shaped electrodes 7 are changed from the vertical state in which their axes are the feed direction,
With the guide portion 21, the connecting portion 14 and the guide portion 22,
The workpiece 2 is smoothly guided so as to match the axial direction of the processing hole 23 to be processed. Therefore, it is possible to perform electric discharge machining on the workpiece 2 at the same time for a predetermined plurality of machining holes 23.

After the above processing is completed, the rod-shaped electrode 7 is raised, and the table 1 is moved through a control device (not shown).
For example, in FIG. 1 and FIG. 2, the processing holes 23 in the next row are processed by moving the processing holes 23 in a direction orthogonal to the paper surface by a predetermined pitch. In this case, the support base 4 fixed on the table 1 and the bracket 11 supporting the approach portion holder 8 and the guide portion holder 9 relatively move in a direction orthogonal to the moving direction of the rod-shaped electrode 7 via the sub-table 15. Since it is formed so as to be possible, the relative movement between the rod-shaped electrode 7 and the workpiece 2 as described above can be smoothly performed without any trouble.

When it is desired to secure a space on the mounting table 3 when the rod-shaped electrode 7 is replaced or the work piece 2 is attached and detached, the bracket 11, the approach portion holder 8 and the guide portion holder 9 are removed. Alternatively, for example, when the bearing 12 and the guide 13 are restrained from moving relative to each other in the vertical direction by bolts or other means, the head 5 is moved upward, so that the bracket 13, the approach portion holder 8 and the guide 13 together with the guide 13 are moved. The part holder 9 may be configured to be raised.

FIG. 3 is an enlarged sectional view of an essential part showing an electric discharge machining mode in another embodiment of the present invention, and the same portions are designated by the same reference numerals as those in FIG. In FIG. 3, reference numeral 24 denotes a concave portion, which corresponds to the concave portion 64 shown in FIG. 8 and is provided on the surface of the blade which is the workpiece 2 in the downstream direction (right direction) of the gas flow in the machining hole 23.

In FIG. 3, first, as shown by a chain line, the rod-shaped electrode 7 is moved in the longitudinal direction to discharge the machining hole 23 in the workpiece 2 and then the rod-shaped electrode 7 is slightly moved up. By performing electric discharge machining while relatively moving the workpiece 2 and the rod-shaped electrode 7 in the directions of three orthogonal axes (XYZ directions), the recess 24 having a predetermined shape can be machined. FIG. 4 is a plan view showing the recess 24 in FIG. 3, and the recess 24 is formed by moving the rod-shaped electrode 7 relative to the work piece 2 as indicated by a plurality of circles as shown in FIG. It is formed.

FIG. 5 is an explanatory view of a main part configuration showing still another embodiment of the present invention, and the same portions are denoted by the same reference numerals as those in FIG. In FIG. 5, reference numeral 31 is a main body, and
It is a stationary component member corresponding to the support column 52 or the feed mechanism 53 in. Next, 32 is a guide rod, the lower end of which is connected to the approach holder 8 through the connecting member 33, and the upper end of which is engaged with a guide 34 provided in the main body 31 so as to be vertically movable.

A feeding device 35 is provided with a worm wheel 37 and a pinion 38 fixed to a feed shaft 36 rotatably provided in the main body 31, and the pinion 38 is engaged with a rack 39 provided on the guide rod 32. In combination, worm wheel 37 is configured to engage worm 40. Therefore, by rotating the worm 40 with a handle (not shown), the guide rod 32 can be moved up and down by the pinion 38 and the rack 39. That is, the approach portion holder 8 and the guide portion holder 9 can be moved up and down, and both members can be held at arbitrary positions.

With the above structure, as in the case of the embodiment shown in FIG. 1, the approach portion holder 8 and the guide portion holder 9 can be held at a predetermined position for processing, and the rod-shaped electrode 7 can be replaced. Alternatively, at the time of attaching and detaching the work piece 2, the approach portion holder 8 and the guide portion holder 9 are moved upward through the guide rod 32 (in parallel with the raising of the rod-shaped electrode 7 by the head 5), and the mounting table is moved. A space can be secured above 3.

In the present embodiment, the hole drilling of the blade for the gas turbine was described as the workpiece, but the present invention is not limited to this, and can naturally be applied to the drilling of other workpieces. It can be widely applied to drilling holes having an axis that intersects the longitudinal direction of the rod electrode. Further, an approach portion holder and a guide portion holder for guiding the moving direction of the rod-shaped electrode so as to match with the axis of the processing hole are formed so as to be detachable and proximate to the workpiece through, for example, a fluid pressure cylinder or other driving means. You can also do it. Further, by appropriately selecting the cross-sectional shape of the rod-shaped electrode, it is possible to perform electric discharge machining of holes whose cross-section is not circular.

[0027]

EFFECTS OF THE INVENTION Since the present invention has the structure and operation as described above, the following effects can be obtained.

(1) A plurality of holes having axis lines intersecting with the feed direction of the rod-shaped electrode at different angles can be simultaneously formed. (2) Since a plurality of holes can be drilled by one setup, it is possible to perform hole drilling work with high efficiency including automatic operation, and it is possible to greatly reduce the drilling cost.

(3) Even when a continuous recess is formed around the hole, either continuously or independently of the hole processing,
A plurality of pieces can be processed successively.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a main part configuration showing an embodiment of the present invention.

FIG. 2 is an enlarged partial cross-sectional explanatory view showing an approach portion holder 8 and a guide portion holder 9 shown in FIG. 1 and the vicinity thereof.

FIG. 3 is an enlarged sectional view of an essential part showing an electric discharge machining mode in another embodiment of the present invention.

FIG. 4 is a plan view showing a recess 24 in FIG.

FIG. 5 is an explanatory diagram of a main part configuration showing still another embodiment of the present invention.

FIG. 6 is an explanatory diagram of a main part configuration showing an example of a conventional electric discharge machine.

FIG. 7 is a cross-sectional view showing an example of a blade for a gas turbine.

8 is an explanatory view showing the vicinity of a cooling hole 63 in FIG. 7, (a) showing an enlarged cross section, and (b) showing an arrow A direction in (a).

[Explanation of symbols]

 6 electrode head 7 rod-shaped electrode 8 approach part holder 9 guide part holder 14 connecting part

Claims (2)

[Claims] 1. An electric discharge machine for machining a hole in a material to be processed, the hole having an axis intersecting the longitudinal direction of a flexible rod-shaped electrode, wherein the rear end of the rod-shaped electrode is held and moved in the longitudinal direction of the rod-shaped electrode. An approach part holder and a guide part holder are integrally formed with a predetermined gap between the electrode head formed so that it is possible to work and the table on which the work piece is placed. In the direction of movement of the workpiece, and the guide holder is provided with a hollow guide portion having an axis in the axial direction of the machining hole of the workpiece, and the axis is substantially tangential between the guide portions. The electric discharge machine is characterized in that a hollow connecting portion having a curved axis line is provided, and the rod-shaped electrode is configured to be movable in the longitudinal direction via the guide portion and the connecting portion. 2. The electric discharge machine according to claim 1, wherein the approach portion holder, the guide portion holder, and the table are formed so as to be relatively movable in a direction orthogonal to the moving direction of the rod-shaped electrode.