JPS62259720A - Electrode for wire-cut electric-discharge machining - Google Patents

Abstract

PURPOSE:To keep odd wire disconnection due to discharge concentration, by constituting an electrode for wire-cut electric-discharge machining in a way of covering a wire rod outer surface with a covered layer consisting of a semiconductor material or a material mixing this semiconductor material in a low melting-point metallic material. CONSTITUTION:A covered layer 21 is formed in a wire electrode 20. This covered layer 21 is made up of an elemental semiconductor material or such one mixing directly a compound semiconductor material or into an alloy making a low melting-point metallic material or these ones the main ingredient. With the presence of this covered layer 21, size of a discharge current is subjected to a restriction through which discharge is dispersed whereby discharge concentration is not entailed there at all, and wire disconnection due to this discharge concentration is hard to occur and, what is more, high speed machining comes possible to be done without enlarging an electrode diameter.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a wire cutter/electrical discharge machine, and particularly to a structure of a wire electrode thereof.

[Conventional technology]

FIG. 4 is an explanatory diagram showing an example of a conventional wire-cut electrical discharge machine. In the figure, (1) ζ supply bobbin (2)
The wire electrode (31t) is directly connected to the electromagnetic brake (3a) and applies a predetermined tension to the wire electrode (1), and the brake roller (4a), (4b) and (4C) are respectively connected to the wire M1i (31t). It is an idler that changes the running direction of 11. (5) is the upper guy 1: double power feeding die,
(6) is a lower guide/power feeding die. These upper guide (5) and lower guide (6) are arranged inside the machining liquid jetting nozzles (71, (81), respectively.

(9) is a pump that supplies machining fluid, and is connected to machining fluid jetting nozzles (71, (81) via pipes.

The wire electrode (1) has an upper guide (5) and a lower guide (6).
), and is opposed in a predetermined direction to the workpiece indicated by the symbol (support). (Il+ is a pulse power supply unit for applying voltage between the wire electrode (1) and the workpiece (12+) to cause discharge. α3)
is the wire electrode feeding roller, and pull out the wire electrode (1) from the feeding bobbin (2) and run it at a predetermined speed.

The operation of the wire-cut electrical discharge machine configured as described above will be explained as follows. First, the wire electrode (
1) and the machining fluid jet nozzle (7) coaxially.

While spouting the machining liquid 001 from (8), a pulse voltage is applied between the wire electrode (1) and the workpiece side by the pulse power supply unit 1-QD. In the minute gap between the facing wire electrode (1) and the workpiece α2, electrical discharge is repeated using the machining fluid as a medium, and a part of the workpiece side is melted and scattered by the thermal energy during the discharge.

In addition, the relative movement between the wire Ti pole (1) and the workpiece α2 to maintain a constant opposing micro-gap and to perform intermittent discharge is numerically controlled by an X-Y cross table (not shown). It is usually done by this method. In this way, by repeating electrical discharge and controlling the X-Y table, machining grooves are continuously formed, and the workpiece (121) is machined into an arbitrary shape.

[Problem that the invention seeks to solve]

In the conventional wire-cut electrical discharge machine as described above, a single brass wire is mainly used as the wire M 4'U fil. If the electrode is made of a metal material, the occurrence of discharge tends to be concentrated, and once the discharge is concentrated, a difference in diameter occurs due to wear of the wire electrode. Then, the wire electrode becomes easily disconnected at the suction part. There is a problem in that this tendency becomes more pronounced as the input energy added between songs increases.

The present invention was made to solve these problems, and an object of the present invention is to obtain an electrode for a wire-cut electrical discharge machine that avoids discharge concentration and prevents wire breakage.

[Means for solving problems]

The electrode for a wire-cut electrical discharge machine according to the present invention has its outer surface covered with a coating layer made of a semiconductor material or a material in which a semiconductor material is mixed with a low-melting point metal material.

[Effect]

In the wire-cut electric discharge machine electrode according to the present invention, a coating layer is formed on the outer surface of the RI pole wire, and when electric charge accumulates in the capacitor formed between the poles and discharges, a capacitor is formed. Since the material itself has electrical resistance, the magnitude of the discharge current at one location is limited. Therefore, a plurality of discharges occur within the same electrode surface, and the discharges are dispersed.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

FIGS. 1(A) and 1(B) are an explanatory diagram showing a state in which an electrode and a workpiece face each other according to an embodiment of the present invention, and an equivalent circuit diagram thereof. In the figure, (support) is the workpiece, ■ is the wire electrode, and Qυ is the coating layer of the wire electrode (■). This coating layer Qυ is made of a single semiconductor material or a compound semiconductor material (hereinafter simply referred to as a semiconductor material) directly or mixed in a low melting point metal material or an alloy mainly composed of these materials, and is made of conventional metals (such as brass). ) The surface of the wire electrode is coated. Due to the existence of such a covering layer Qυ, an equivalent circuit as shown in the same figure (B) is obtained, in which R-r indicates a resistor and C indicates a capacitor, respectively. When the covering layer Qυ contains a semiconductor material, the resistances R and r in FIG. 1(B) become large, and the magnitude of the discharge current is limited. Further, if a low melting point metal material is further included, electrode wear increases, which easily widens the distance between the electrodes, and the discharge is dispersed to other regions with high potential gradients.

Figure 2 shows an experimental setup for measuring the dispersion state of discharge when using the above wire electrode.The workpiece is divided into three by insulating layers, Discharge current 'l, 'Hp flowing through each insulated workpiece
13 current transformers (23a) and (23b) respectively
.

(23c).

In the apparatus shown in Fig. 3, the waveforms of each current 1□ to 13 when the wire electrode shown in Fig. 1 is touched are shown in Fig. 3 (A).
FIG. 3B shows a case where a conventional wire electrode (1) (brass wire) is used.

As is clear from the figure, it can be seen that when the wire electrode (3) is used, the discharge is significantly more dispersed than in the conventional case.

〔Effect of the invention〕

As is clear from the above explanation, the wire-cut electric discharge machine according to the present invention? The llS pole has a coating layer containing a semiconductor material, etc., which limits the magnitude of the discharge current, which disperses the discharge and prevents discharge concentration, making it difficult for wire breakage to occur due to discharge concentration. There is. For this reason, it has become possible to increase the energy input to the wire electrode, and it has become possible to realize high-speed machining without increasing the diameter of the wire electrode.

[Brief explanation of drawings]

FIGS. 1(A) and 1(B) are explanatory diagrams and equivalent circuit diagrams showing a state in which an electrode for a wire-cut electrical discharge machine and a workpiece face each other according to an embodiment of the present invention, and FIG. Figures 3 (A) and (B) are explanatory diagrams showing the experimental equipment for measuring the dispersion state of discharge. Figure 4 is a diagram showing the configuration of the wire electrical discharge machine. - Wire electrode, 0211...Covering layer Note that the same reference numerals in the drawings indicate the same or corresponding parts. Agent Patent Attorney Masaru Sato Fig. 1 (A) (8) Fig. 2 (0) f, case of IFA's revocation (20) - (b)
) 4 wires qhi, h(on)
．． Figure 4

Claims (1)

[Claims] 1. An electrode for a wire-cut electrical discharge machine, the outer surface of which is covered with a coating layer made of a semiconductor material or a mixture of a low melting point metal material and a semiconductor material.