JPS5959322A - Electrode for discharge machining of minute holes - Google Patents

Abstract

PURPOSE:To offer an electrode for electric discharge machining of minute holes, which is easy to manufacture and durable for a long period, by making the electrode in such a construction that rotation of electrode does not involve deflection, that any wire commercially available can be used therein, and that the wire is used continuously being sent off. CONSTITUTION:A wire 1 as electrode for discharge machining is set under guidance of a wire guide 2 made of ceramics to be mounted on a mandrel 3 made of hardened steel. The wire guide 2 is fitted by pressure in the mandrel 3 at a fit of h6 60 p6 according to JIS specification. As wire guide 2 is used a ceramic pipe designed for an optical fiber connector with its periphery's concentricity with the hole below 1mum, and the mandrel 3 is equipped with its periphery's concntricity with the hole below 1mum. The mandrel 3 is supported by a scroll chuck 11 and a V-shaped block bearing 12, and the discharge machining is carried out by mounting a pulley 13 on the mandrel 3 and rotating by a belt 14. When the wire 1 has worn to a certain degree, a screw 5 is loosened and the wire 1 drawn out to provide continued processing.

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to an electrode assembly for microhole electrical discharge machining.
No deflection occurs even when the electrode is rotated, and a commercially available small diameter wire (71u, polar core wire) can be used as an electrode attachment. When the electrode wears out, the wire that becomes the electrode can be pulled out and used repeatedly. An object of the present invention is to provide an electrode structure for micro-hole electric discharge machining, which has a long blue line and is easy to manufacture. .

Conventional structure and its problems In electrical discharge machining of micro holes with a diameter of 0.1 mm or less, -1, Machining "When the electrode is stopped and when it is rotated" 2
There are two methods. Avoid full rotation of the electrode 1/
ζ Yo Shika rJ direction of machining speed - L-2 The roundness of the machined hole, the shape accuracy of the white clay, but considering the runout of the electrode and the molding time of the electrode - C1 Conventional time, electrode The main body is the addition of ・Iku・11-.

When making electrodes (11) during machining with the electrode stopped, if you use a small diameter wire that does not require electrode production by cutting, you can use one that is cut directly into the holder, or a one-diameter wire that does not require cutting. Remove the plating, reinforce it, and soak it./Protect, kite, and chucking ζ, glass, and Ruhi wires with +I-, and when using a relatively thick wire, use the tip that will become the processing electrode. There is an electrode whose only part is made thinner by electrolytic polishing.

However, with any of the electrode structures, the concentricity between the tip of the electrode on the processing side and the outer circumference of the electrode cannot be less than several 71, and it is difficult to install the electrode perpendicularly to the workpiece. It was impossible to rotate the machine and perform machining.

Furthermore, when performing electrical discharge machining with an electrode stop, the wire shape is transferred to the workpiece, so if machining is performed using a commercially available small diameter wire that is not finished with sufficient dimensional accuracy, it is difficult to make a perfect circle. It was difficult to drill holes with good quality.

On the other hand, when machining is performed by rotating the electrode, the electrode structure is formed using a chuckable round rod with a diameter of 1mm4U, which is formed into an electrode of the desired diameter by rotating the electrode phase and using reverse discharge. Ta.

With such a molded electrode, sufficient accuracy can be obtained, but it takes about 1 hour to mold a micro-large electrode with a diameter of 30 μIll from an electrode phase with a diameter of 1 mm.
It takes a considerable amount of time to produce. 'Also, the molded part (the part with a diameter of 3014 rtt) is short, so its lifespan is short, and once it is removed from the handle, it warps, so it has to be used while being molded each time it is processed. .

Purpose of the Invention The present invention has been made in view of the above-mentioned problems, and it rotates the electrode by aligning the center axis of the support tube with the center of rotation of the nine rotating supports with high precision. There is no deflection, and when the electrode is worn out due to discharge, it can be pulled out from the rotating support, and a commercially available thin core wire can be used as the electrode material. [Purpose and purpose] To provide an electrode structure for micro-hole electrical discharge machining that is easy to manufacture, has a long life, and is easy to produce.
It is something that

SUMMARY OF THE INVENTION In order to achieve the above-mentioned objects, the present invention supports the electrode core wire in a slidable manner on a support tube, and also connects the outer periphery of the support tube with the same hole of the hole through which the electrode core wire is inserted. The support tube is press-fitted into the rotary support with a sufficiently high degree of concentricity and a sufficiently small degree of concentricity between the support tube insertion hole and the outer periphery.

Description of examples Hereinafter, one embodiment of the present invention will be explained using gold drawings.

FIG. 1 shows an overall configuration diagram of an embodiment of an electrode assembly for microhole electrical discharge machining according to the present invention, FIG. 2 shows a side sectional view of the same, and FIG. 3 shows a side view of the same.

A thin wire (electrode core wire) 1 that becomes the processing electrode.

The rod is guided by a wire guide (support tube) 2 made of lamic lamic and placed on a mandrel (rotary support) 3 made of hardened steel.

Wire guide 2 iJ: J I 5 as shown in Figure 2
The mandrel 3 is fitted with a culm of h6-p6 and a length of 71 is placed.

In this embodiment, the wire guide 2 is a ceramic pipe for optical fiber connectors in which the outer circumference and the hole have a concentricity of 1 ltm or less, and the mandrel 31-J has a concentricity of 1 μm or more and the concentricity of the outer circumference and the hole is 1 ltm or less. It has been processed. The above two pieces are combined and press-fitted at the position where the fringes of the electrode 1 are minimized. Since the press-fitting allowance in the longitudinal direction is sufficiently long compared to the wire guide diameter, there is little inclination. This y
The bending of the wire is very small.

Here, a method for manufacturing a wire guide 2 whose outer periphery and hole have a sufficiently small diameter of 1/I II+ or less will be described with reference to FIGS. 4(a) and 4(b).

If the wire guide 2 is made of sintered material, for example, ceramics, the guide can be manufactured by vacuum extrusion (7 molding).
Becomes Noh. FIG. 4(a) is a left side view of the vacuum extrusion molding 62, and FIG.

In other words, mold d has 1 gold and 6. It consists of a pin 7 and a pin holder 8 in which the pin 7 is embedded, and a ceramic kneaded phase 9 is placed in the fourth (1(b)) space between the hebin polder 8 in the direction of the arrow from the left. The twisted material 9 is connected to the pin 7 and [21 gold 6
(It becomes a pipe shape and is extruded from the outside of the mold.) Here, the combination of pin 7 and D gold 6 is extruded by increasing the degree of A'Ft. LL-HBI can obtain 10 lt rrt or less. After completion of this process, a wire is passed through the hole and the outer circumference of the pipe is cylindrically ground using a centerless grinder using the wire as a guide. Noise degree 371'
n? The following high-precision ceramic pipes can be obtained.

In pipe manufacturing by extrusion molding, no problems arise in manufacturing even if the outer diameter of the pipe becomes thicker than the hole diameter, or even if the hole becomes deeper.

Now the outer diameter of the pipe 2. If the diameter is 5 mm N degrees or more, the rigidity of the tool is sufficient even if holes are drilled on the mandrel using the usual method, such as reaming after trilling. Holes with concentricity are obtained.

Next, a method of press-fitting the wire guide 2 and mandrel 3 together at a position where the deflection of the electrode 1 is minimized will be described.

Figure 5] shows the positional relationship between the hole of the wire guide and the outer periphery, and Figure 5(b) i-1 shows the positional relationship between the hole of the mandrel and the outer periphery. In the figure (a), the hole L·○' is offset by rl at an angle θ1 from the center O of the outer periphery of the wire guide 2. In FIG. In the same figure (b), the hole center O"' of the mandrel 3 is the center hole of the outer periphery 0"
The position of the angle θ2 is shifted by r2.

When combining this wire guide 2 and 1 mandrel 3, the mandrel is rotated clockwise by θ2 in FIG. 5, and the wire guide 2 is rotated counterclockwise by 1800-01° and then combined, as shown in FIG. The positional relationship will be like this.

That is, the concentricity R between the hole of the wire guide 2 and the mandrel 3 in the combined state is shown by the formula (1), R-r 2 r 1 . . .
(1) The concentricity R after assembly is better than the conversion 1i in the middle 1 body.

Therefore, by assembling the wire guide 2 and mandrel 3, each of which has a concentricity of a few micrometers, it is possible to completely eliminate the warping and deflection.
An electrode structure for electrical discharge machining with a small hole is obtained.

In actual work, a tool microscope with high magnification (xsoo) is used to determine the concentricity '6+11, and θ1. θ2. The position of the combination is determined by determining the position of the combination, and the entire press-fit is performed.

Now, as described above, wire guide 2 and mandrel 3
is set up, and the -force 1 [electrode--
- In order to hold the very thin wire 1 in the mandrel with good straightness and to obtain electrical continuity with the mandrel 3, the rear end of the wire 1 is fixed as shown in Fig. 7. A vibro made of a conductive material is bonded with solder (marquee, etc.) and fixed to the mandrel 3 with a metal screw 4, as shown in FIG.

The outer diameter of wire guide 2 and the hole diameter of mandrel 3 are JIS
The fit is about h6-h7.

In actual electrical discharge machining, the mandrel 3 is chucked with a scroll chuck 11 as shown in FIG. This is done by attaching it and rotating it directly with the belt 14. If the wear of the wire 1 has progressed after performing [addition xl:], loosen the screw 6 shown in Fig. 2 and remove the wire
It can be scooped by letting it fall naturally due to gravity or by pulling it out with tweezers.

There are two ways to guide the wire 1, as shown in FIG. 10, using a guide 15 with a sufficiently long guide section, and as shown in FIG.
There is a method using 6. In the case shown in Figure 11, it is passed through when a sufficient length of the guard cannot be obtained depending on the hole diameter. In addition to ceramic, the wire guide may be made of ruby, sintered metal, hard metal, or the like. Regarding the quality of the pipe 5, it may be of any conductivity.

In this embodiment, the clearance between the wire 1 and the wire guide 2 is about 111, which can be ignored.

Also, in the above explanation, Den 4? Although the case where i1 is rotated and used is shown, it is also possible to perform processing without rotating the electrode.

DETAILED DESCRIPTION OF THE INVENTION According to the present invention, as described in detail, the support tube is press-fitted into the rotary support 11 so that there is almost no misalignment between the center of rotation of the rotary support and the center of the hole in the support tube, and the electrode core wire is inserted into the support tube. Because the support is slidable, there is almost no deflection even when the electrode is rotated, and a microhole with high roundness and shape accuracy can be obtained. Since the electrode can be fed out and used, and commercially available small-diameter core wires can be used as the electrode, an electrode for micro-discharge]]-1 that can be used for a long period of time and is easy to manufacture can be obtained.

[Brief explanation of the drawing]

Fig. 1 is an overall configuration diagram showing one embodiment of the microhole electrical discharge machining ffl electrode structure of the present invention, Fig. 2 is a cross-sectional view of the same, Fig. 3 is a front view of the same, Fig. 4 (a), ( b) is a side view and a cross-sectional view of the base used for manufacturing the wire guide, FIGS. Figure 7 is a diagram illustrating the main parts of the second embodiment, Figures 8 and 9 are diagrams explaining how to use the same embodiment, and Figures 10 and 11 are configuration examples of the support tube. FIG. 1... Wire (electrode core wire), 2,115.16
...Wire guide (support tube, 3...
Man l-' l/le (rotating support), 4... Pipe fixing screw, 5... Pipe, 6... Cap, 7... Pin, 8 ...Bin holder,
11...Scroll chuck, 12...
Bearing, 13...Pulley. Name of agent: Patent attorney Toshio Nakao and 1 other person
1r:A? Figure 2 Figure 3 Figure 4 ((1)
(b) (d) lb no 6
Figure 15 Figure 8 Death Figure 9? vHs ] OPI Figure 11 12F

Claims (2)

[Claims] (1) The electrode core wire is inserted through the hole and the support tube is slidably supported, and the hole through which the electrode core wire is inserted is sufficiently concentric with the outer periphery. An electrode assembly for micro-hole electrical discharge machining, which is press-fitted into a rotary point j with sufficient concentricity between the hole through which the support tube is inserted and its outer periphery. (2) The direction of the deviation lj between the center of the hole L through which the electrode core wire of the support tube is inserted and the center of the outer periphery is the deviation between the center of the hole through which the support tube of the rotary support is inserted and the center of the outer periphery. The electrode assembly for microhole electrical discharge machining according to claim 1, wherein the support tube is press-fitted into the rotary support body so as to coincide with the direction.