JPH0259222A - Manufacture of working electrode guide - Google Patents

Abstract

PURPOSE:To manufacture a working electrode guide for discharge fine holes by forming a straight hole with a uniform bore guiding a working electrode, and a slit extending outward from the straight hole at groove width narrower than the bore size in a working electrode guide body by means of wire-cut electro-discharging machining. CONSTITUTION:In a working electrode guide 10', there are provided with a guide hole 42 of a straight hole of the same axis as an axis of a workpiece 10 serving as a body, slits 43a-43d extending outward therefrom and through holes 44a-44d in parallel with the guide hole 42 at a proper diameter to each end of these slits. In the through hole 44c, there is provided with a slit 45, opened to the outside, for admission or retraction to or from the workpiece 10, of a wire electrode. A bore of the guide hole 42 is made somewhat larger than the outside dimension of a working electrode being guided by this guide, and each groove width of these slits 43a-43d is made smaller than the bore, and formed by means of wire electro-discharge machining. Therefore the pipelike electrode guide for fine hole work can be easily manufactured.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a method for manufacturing a machining electrode guide for electrical discharge small hole machining, which is used when drilling a narrow hole in a workpiece by electrical discharge machining. be.

(Prior art) When drilling a small hole of approximately 0.51φ or less in a workpiece by electric discharge machining, a pipe-shaped electrode is used as a machining electrode, and machining liquid is injected into the discharge machining gap through the pipe-shaped electrode. A small-hole electric discharge machine is generally used in which the pipe-shaped electrode is rotated while supplying a sufficient amount of the material, and machining is performed by a machining pulse applied between the pipe-shaped electrode and the workpiece.

In this type of electric discharge machine, the electrode wears out rapidly, so a long machining rTX and pole are installed, and a machining electrode guide installed near the workpiece is placed close to the tip of the TL pole. The structure is such that the long processing electrode can be rotated stably.

The conventional machining electrode guide used for the purpose mentioned above is
As shown in FIG. 5, the main body 21 and the main body 21
has a sleeve portion 22 integrally extending downward from the lower end surface 21a along the central axis thereof, and has a through hole into which a desired pipe electrode 30 for processing is inserted through the main body portion 21 and the sleeve portion 22. 23 is formed. This through hole 23
For example, three support members 24, 25, and 26 are provided inside to support the rotating pipe electrode 30 for processing. These support members are made of a material with excellent wear resistance such as sapphire, and the processing pipe electrode 30, which rotates and interlocks along the axial direction, is connected to the three support members 24, 25.
．． 26, it is supported at three points.

(Problems to be Solved by the Invention) The conventional machining electrode guide described above has a structure in which the machining electrodes are supported at intervals by support members provided at intervals within the through hole. The problem is that it is complicated and its manufacturing cost is high. Also,
In this conventional machining electrode guide, as the long machining pipe electrode is rotated, the machining pipe electrode 30 is placed between the chuck 31 and the machining electrode guide 20 in the fifth position.
When vibration occurs as shown by the dotted line in the figure, this vibration is transmitted downward as shown by the dotted line, and the machining pipe electrode portion protruding from the machining electrode guide 20 also A runout will occur as shown by the chain line. For example, in the case of a 0.21Φ machining pipe electrode, if its protrusion length is 10 mm, this deflection will be approximately 70 μm at its tip.

For this reason, not only machining accuracy is not achieved, but also the discharge state in the discharge machining gap becomes unstable, resulting in another problem that the time required for machining becomes extremely long.

Furthermore, as mentioned above, conventional machining electrode guides have a structure in which a support member such as a sapphire guide is placed in the through hole through which the electrode passes. When pulling up the pipe electrode, if the guide hole of the processing electrode guide is clogged because the debris generated around the pipe electrode for processing is scraped off in the through hole, it is necessary to remove it for the support member. It is extremely difficult to remove, which makes it unusable, and it also has the problem of being uneconomical.

An object of the present invention is to provide an improved method for manufacturing a machining electrode guide for electrical discharge small hole machining, which makes it possible to eliminate the above-mentioned problems in the prior art.

(Means for Solving the Problems) According to the present invention, in a method for manufacturing a machining electrode guide for guiding a machining electrode for electric discharge small hole machining, the main body of the machining electrode guide prepared in advance includes: Wire-cut electric discharge machining is performed to create a straight guide hole having a uniform inner diameter for guiding a required machining electrode, and a groove width narrower than the inner diameter extending radially outward from the guide hole. It is characterized by forming a slit.

(Function) When forming guide holes and slits connected to the guide holes in the main body by wire-cut electrical discharge machining, these can be formed in one machining process regardless of the number of slits.
It is possible to process guide holes of any diameter and slits connected to them.

(Example) Fig. 1 shows a workpiece that will become the main body of the machining electrode guide for manufacturing a machining electrode guide for guiding a machining electrode for electric discharge small hole machining by the method of the present invention. 10 is shown set in a wire-cut electrical discharge machine 20. The wire cut electric discharge machine 20 includes upper and lower guides 22 and 23 that support and guide a wire electrode 21 of a required diameter.
This is a known device comprising a running wire electrode 21 and current-carrying members 24 to 27 that are electrically connected, and only the main parts thereof are shown in FIG.

The workpiece 10 is made of a material such as carbide, and has a cylindrical shape with one end having a conical shape.
is firmly gripped by an electrically grounded conductive clamp member 28 such that its axis is parallel to the axis of the wire electrode 21 in the processing area of the workpiece 10. A machining pulse is applied between the workpiece 10 and the wire electrode 21 from a machining power source (not shown) via current-carrying members 24 to 27, and a machining pulse is applied between the workpiece 10 and the wire electrode 21. The workpiece 10 is machined by sparks generated in the discharge machining gap that is formed. Note that actually, machining fluid is supplied to this discharge machining gap, but the first
In the figure, illustration of a device for supplying machining fluid is omitted.

The clamp member 28 is fixed to an X-Y moving table (not shown) by appropriate means, and by moving the X-Y moving table in a direction perpendicular to the running direction A of the wire electrode 21, the workpiece 10 can be moved there. It can be processed into a shape consisting of a plane parallel to the axis or a curved surface.

FIG. 2 shows the planned shape of the machining electrode guide to be machined by the method of the present invention, on the upper end surface tO of the workpiece 10.
This is shown as a machining trajectory on a. As shown in FIG. 2, the wire electrode 21 and the workpiece 20 are sequentially processed from the processing start point a to b+c→... until the processing end point t, where the wire electrode 21 and the workpiece 20 are relatively translated. By performing the movement, the shaded portion in FIG. 2 can be removed.

FIG. 3 shows the processing electrode guide 10' processed in this manner. The processing electrode guide lO' includes a straight guide hole 42 coaxial with the axis of the workpiece 10 serving as the main body, and a plurality of slits 43a, 43b extending from the guide hole 42 toward the outside in the radial direction of the main body 41. , 43
Through holes 44 & 44 d having appropriate diameters and parallel to the guide hole 42 are formed at the end portions of the guide holes 43 c and 43 d, and the sleeves 43 a to 43 d. The through hole 44c is
The wire electrode 21 is opened to the outside through a slit 45 formed by a machining trajectory a-b for entering the workpiece 10 and a machining trajectory S-t for leaving the workpiece 10.

Here, the inner diameter of the guide hole 42 is a predetermined dimension that is slightly larger than the outer diameter dimension of the processing electrode guided by it, and the width of each groove of the sleeves 43a to 43d is the same as that of the guide hole 42.
The machining locus shown in FIG. 2 is determined so that the required dimensions and shape are narrower than the inner diameter of. Of course, this machining trajectory is determined in the same manner as in the case of normal wire cut electric discharge machining, taking into account the diameter of the wire electrode used, the machining gap width required for electric discharge machining, and the planned machining shape. There is.

In this way, according to wire cut electrical discharge machining, for example, 0
．． A machining electrode guide for guiding a pipe-shaped electrode for machining a small hole of about 2Φ can be fabricated very easily. This type of machining can be performed automatically by inputting the machining shape data showing the required machining trajectory shown in Figure 2 and other necessary data into the numerical control device that controls the movement of the X-Y moving table. It can be processed into

As described above, this machining electrode guide 10' can be easily and precisely formed by wire-cut electrical discharge machining, and has the following advantages.

That is, since the guide hole 42 is a straight hole, even if the upper part of the circular electrode for machining guided by it generates vibration due to rotation, this vibration will be transmitted to the lower end of the circular electrode for machining that forms the discharge machining gap. Therefore, electrical discharge machining of fine holes can be performed accurately, stably, and at a high level.

After machining is completed, when the circular electrode for machining is pulled up by raising the head and the tip of the circular electrode for machining is pulled out from the guide hole 21 of the electrode guide 10' for electric discharge machining, the circular electrode for machining is removed by electric discharge machining. The burr generated at the tip of the electrode is scraped off by the guide hole 21, and the burr is removed by the guide hole 2.
Invades and adheres to 1. However, since the guide hole 21 is a straight hole, this type of metal piece can be easily removed by inserting an appropriate circular rod-shaped body into the guide hole 21, and can also be removed using a pin cage or the like.
These metal pieces can be easily removed via 3d. Therefore, unlike the conventional electrode guide shown in FIG. 3, it can be used repeatedly and is extremely economical. Note that in this case, the through holes 44a to 4
4d, foreign matter discharged from the guide hole 42 can be effectively taken out to the outside through the corresponding slit, but these through holes may be provided as necessary. In that case, the slit may be provided in all or only part of the slit. Moreover, the number of slits can be one or more and an arbitrary number can be provided.

In the above embodiment, the groove 45 was formed to eliminate the need for a machining start hole, but the groove 45 is not necessarily necessary. For example, after machining the first through hole 44c as the machining start hole, the wire is Start electric discharge machining, d-+e→
The machining may be completed at point r after passing through...

As can be seen from the above description, the processing electrode guide 50 as shown in FIG. 4 is also used. Similarly, it can be machined by wire cut electrical discharge machining. The processing electrode guide 50 shown in FIG. 4 includes a main body 12 having a substantially conical shape, and a sleeve integrally extending downward coaxially with the main body 12 from the center of the lower surface 12a of the main body 12. The main body part 12 and the sleeve part 13, in which a guide 14 is formed coaxially with the axis of the main body part 12 and the sleeve part 13, are made of carbide.

The inner diameter of the guide hole 14 is set to be slightly larger than the outer diameter of the circular electrode for processing to be used.
is a straight six, and the circular electrode for machining is supported and guided by the entire inner circumferential wall of the guide hole 14, and when the circular electrode for machining is rotated, the deflection of the circular electrode for machining is caused by the circular electrode guide for machining 10. The structure is such that it does not transmit to the electrode portion protruding from the sleeve portion 13.

The machining electrode guide 10 is further provided with a slot 15 having a groove width narrower than the inner diameter dimension of the guide hole 14 which extends radially outward and reaches each outer peripheral surface of the main body portion 12 and the sleeve portion 13. It is formed.

This machining electrode guide 50 can also be precisely machined by wire-cut electric discharge machining in the same manner as the machining electrode guide 10' shown in FIG. 3 is formed by wire-cut electric discharge machining.

(Effects of the Invention) According to the method of the present invention, a hole of an extremely small diameter having a slit connected to a straight hole for guiding an electrode and a special shape having a narrow width slit are used for machining a small hole by electrical discharge. Since the electrode guide can be machined easily and with high precision, it can be used repeatedly, is highly economical, and has the effect of being able to provide a machining electrode guide at a low cost that enables high-precision electrical discharge small hole machining. play.

[Brief explanation of the drawing]

Figure 1 is a perspective view showing a workpiece set in a wire-cut electric discharge machine for forming an electrode guide for electric discharge machining according to the method of the present invention, and Figure 2 is a wire-cut electric discharge machine shown in Figure 1. FIG. 3 is a plan view showing the machining trajectory of the workpiece set in the machine; FIG. 3 is a perspective view showing the machining electrode guide obtained by machining the workpiece according to the machining trajectory shown in FIG. 2; FIG. 5 is a perspective view of another machining electrode guide formed by the method of the present invention, and FIG. 5 is a sectional view showing the structure of a machining electrode guide made by the conventional method. DESCRIPTION OF SYMBOLS 10... Workpiece material, 10'... Electrode guide for processing, 20... Ichiban wire cut electric discharge machine, 42... Fist guide hole, 43a to 43d... φ slit. Figure 1 Figure 3 Figure 5

Claims (1)

[Claims] 1. In a method for manufacturing a machining electrode guide for guiding a machining electrode for electric discharge small hole machining, a required machining electrode is guided into the main body of a machining electrode guide prepared in advance by wire cut electric discharge machining. A machining electrode guide characterized by forming a straight guide hole having a uniform inner diameter dimension and a slit having a groove width narrower than the inner diameter dimension and extending radially outward from the guide hole. manufacturing method.