JPH04105821A - Feeding piece for wire cut electric discharging machine - Google Patents

Abstract

PURPOSE:To make one part of the feeding electric power not to be dispersed as a Joule heat, by composing a feeding piece with the conductive material whose electric resistance is smaller than that of a cemented carbide material, and providing a hard material plating layer on the surface. CONSTITUTION:Feeding pieces 20, 22 are formed with the conductive material whose proper electric resistance is smaller than that of a cemented carbide material, and the wear protection is planned with the plating layer 24 of the hard metal material of chrome, etc., being provided on the surface contacted with a wire electrode 13. Thus, the loss of the work energy accompanied by a Joule heat at the contact and electrifying part between the feeding piece and wire electrode is reduced, the electric discharging power to be fed is applied as electric discharging energy effectively, and the work efficiency of the wire cut electric discharging can largely be improved. Also, the generation rates of work flaws and wear on the surface of the feeding piece are reduced sufficiently by the protection layer of the hard metal material of the surface, and the service life of the feeding piece can be improved.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a wire-cut electrical discharge machine, and in particular, a wire-cut electrical discharge machine that comes into contact with a traveling wire electrode to generate electrical discharge between the wire electrode and a workpiece. This invention relates to an improved structure of a feeder for supplying electric power.

[Prior art]

In a wire-cut electric discharge machine, a metal workpiece, which is the material to be machined, is mounted on a worktable that can be moved in two orthogonal axes within a plane, and a wire electrode is run in a fixed direction via the workpiece to move the workpiece. By applying a pulse voltage through a small gap between the wire electrode and the wire electrode, an electric discharge phenomenon is generated, and the discharge energy is used to remove machining debris from the workpiece and perform electric discharge machining on the workpiece. At this time, since the workpiece is controlled to move in two axial directions together with the worktable, a desired shape can be formed on the workpiece by electrical discharge machining.

Conventionally, in such a wire-cut electrical discharge machine, a feeder that contacts a running wire electrode and supplies pulse voltage from an electrical discharge machining power supply as electric power for electrical discharge machining is as follows.
In order to avoid poor electrical contact due to abrasion occurring at the contact portion with the traveling wire electrode, it is formed using a superhard material. That is, normally, a cylindrical or dice-shaped feeder made of a superhard material is placed facing the travel path of the wire electrode.

[Problem to be solved by the invention]

However, the conventionally used cemented carbide associative materials are
Compared to copper material, which is a typical conductive material with low electrical resistance, for example, the latter copper-based material has a specific electrical resistance of about 1.7 μΩ/m, while the latter cemented carbide has a specific electrical resistance of about 20 μΩ. /m, and therefore, between the carbide feeder and the wire electrode, part of the power supplied from the electrical discharge machining power source is dissipated as Joule heat, and a part of the electrical discharge machining energy is wasted. The result is that it is consumed in

Therefore, the present invention aims to solve these problems.

[Means to solve the problem]

In view of the above-mentioned problem to be solved, the present invention considers the material for the feeder of a wire-cut electric discharge machine, and selects the material in order to prevent the dissipation of machining energy due to Joule heat. That is, according to the present invention, in a feeder for a wire-cut electrical discharge machine that supplies electrical discharge force from the electrical discharge machine power source between a work mounted on a work table and a wire electrode running in a predetermined direction, The present invention provides a feeder for a wire-cut electrical discharge machine, characterized in that the feeder is made of a conductive material having a lower electrical resistance than a cemented carbide material. Preferred conductive materials include, for example, oxygen-free copper (specific It is made of a copper material, brass material, etc. with an electrical resistance of about 1.7 μΩ/m. Furthermore, preferably, the surface of the feeder made of a conductive material with low electrical resistance is coated with a metal material that is harder than the main body of the feeder, for example,
A plating layer of chromium or the like is formed to reduce surface abrasion due to contact with the wire electrode. Hereinafter, the present invention will be further explained with reference to the accompanying drawings in terms of its functions, effects, etc.

〔Example〕

FIG. 1 is a schematic diagram showing the configuration of the electrical discharge machining section of a wire-cut electrical discharge machine according to the present invention, FIG. 2 is a perspective view showing the structure of a feeder according to an embodiment of the present invention, and FIG. 1 is a graph diagram showing a comparison of effects between the feeder according to the present invention and a conventional feeder based on an experiment.

As shown in FIG. 1, in the wire-cut electrical discharge machine, a workpiece 12 is mounted on a worktable 11 and can move together with the worktable 11 in two axes within a plane. The directional movement is controlled by an electric discharge machining control device (not shown), such as a well-known NC control device. Wire electrodes 1 are placed above and below the workpiece 12.
Upper and lower wire guides 14.15 are provided for guiding the wire 3 along a predetermined travel path from the wire electrode supply source to the wire electrode winding device via guide rollers 16.17. An electric cable is wired to supply electric discharge machining power from a machining power source.

Then, the feeder 2 is placed inside the upper and lower wire guides 14 and 15.
0.22 is provided, and when this feeder 20.22 comes into contact with the running wire electrode 13, -discharge power is applied.

According to the present invention, the feeders 20 and 22 are both made of a conductive material, such as a copper material or a brass material, whose specific electrical resistance can be significantly reduced compared to a conventional feeder made of a cemented carbide material. It is formed into a cylindrical member or a dice-shaped member.

FIG. 2 shows a cylindrical feeder 20 or 22, and in this embodiment, the main feeder body 23 is formed of the above-mentioned low electrical resistance material, and the surface in contact with the wire electrode 13 is made of chromium, etc. A structure is shown in which a layer 24 of hard metal material is provided to provide wear protection. By depositing and forming such a wear protection layer with a thickness of about 100 to 120 microns by plating, the service life of the feeder 20 or 22 can be extended.

In the case of a cylindrical feeder, the cylindrical surface is used as a contact surface with the wire electrode 13 and as a current-carrying surface, and if the feeder 20 or 22 is periodically rotated around the mounting axis, the contact surface can be updated. can be achieved.

In addition, in the case of a dice shape, cube shape, rectangular parallelepiped shape, etc., the flat side surface is used as the contact and current-carrying surface, and in this case as well, the contact and current-carrying surfaces are replaced so as to be updated periodically. Good. Further, the shape of the feeder 20.22 is not limited to the above-mentioned cylindrical shape or rectangular shape, and may be formed into a multifaceted structure or the like. Furthermore, the feeder 20.22 is not limited to being provided in both the upper and lower wire guides 14.15, but may be provided only inside either one of the wire guides 14 or 15, if necessary. Good example.

According to the feeder for a wire-cut electric discharge machine of the present invention having the above-described configuration, it is made of a metal material or a conductive material that has a lower specific electrical resistance than a conventional feeder made of a cemented carbide material. , the contact between the feeder and the wire electrode and the loss of machining energy due to Joule heat in the current-carrying part are reduced, so the electrical discharge that is supplied from the electrical discharge machining power source to the electrical discharge machining part through the minute gap between the wire electrode and the workpiece is reduced. Electric power is effectively applied as electrical discharge machining energy. As a result, the machining efficiency of wire cut electrical discharge machining can be greatly improved. In addition, if the main body of the feeder is made of a material with low electrical resistance as described above, and a protective layer of hard metal material is formed on the surface by plating, etc., the incidence of processing scratches on the surface of the feeder can be reduced. The incidence of wear is sufficiently reduced, and the service life of the feeder can be improved.

Figure 3 is a graph that experimentally confirms the improvement in machining efficiency of the feeder according to the present invention, and the horizontal axis shows examples of conventional cemented carbide materials and low electrical resistance materials according to the present invention. Copper and brass materials are shown, and the vertical axis is the processing speed (conventional value 100
(expressed as %). From this graph, it was found that in the case of the feeder according to the present invention, the machining speed could be improved by about 20%, and therefore the workpiece machining efficiency per unit time could be improved. Furthermore, it is possible to further improve machining efficiency by increasing the amount of machining fluid discharged from the wire guide to the electrical discharge machining section.
Confirmed experimentally.

〔Effect of the invention〕

According to the feeder of the wire-cut electric discharge machine according to the present invention, the dissipation of machining energy due to Joule heat at the contact between the feeder and the wire electrode and the current-carrying part is reduced, so the electric discharge machining power supplied from the electric discharge machining power supply is reduced. The amount of energy effectively utilized as electric discharge machining energy was improved, and therefore, the machining efficiency of wire cut electric discharge machining was improved.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing the configuration of the electrical discharge machining section of a wire-cut electrical discharge machine according to the present invention, FIG. 2 is a perspective view showing the structure of a feeder according to an embodiment of the present invention, and FIG. FIG. 2 is a graph diagram showing a comparison of effects between the feeder according to the present invention and a conventional feeder based on an experiment. 12...Work, 11...Work table, 13.
...Wire electrode, 14.15...Upper and lower wire guide,
20.22...Feeding electron.

Claims (1)

[Claims] 1. In a power supply for a wire-cut electrical discharge machine that supplies electrical discharge force from an electrical discharge machine power source between a work mounted on a work table and a wire electrode running in a predetermined direction, A feeder for a wire-cut electric discharge machine, characterized in that the feeder is made of a conductive material having a lower electrical resistance than a cemented carbide material. 2. The feeder for a wire-cut electric discharge machine according to claim 1, wherein the feeder is made of the low electrical resistance material and has a plated layer of hard material on its surface.