JPH0457627A - Wire-cut electric discharge machine - Google Patents

Abstract

PURPOSE:To prevent the generation of electric discharge and electric contact due to the fine vibration of a wire electrode and prolong the life of an electric feeder by executing the electricity feed to the wire electrode through a pinch roller which revolves, nipping the wire electrode, besides through the electric feeder. CONSTITUTION:A wire-cut electric discharge machine is equipped with the upper and lower electric feeders 8 and 9 which are connected with one output edge of an electric discharge work power source 10, in contact with a traveling wire electrode 1, and a pinch roller 13 which revolves, nipping the wire electrode 1, and whose revolution is controlled to a prescribed revolution speed. Further, electricity feed is performed from the electric discharge working power source 10 through the surface conductor part of the pinch roller 13. The wire electrode 1 in the electric discharge machining is vibrated by the electric discharge reaction force in a working gap and the turbulent flow of the working liquid which is pressurized and supplied into the working gap and separated from the surfaces of the electricity feeders 8 and 9. However, since electricity is supplied at all times into the wire electrode 1 nipped by the pinch roller 13, the breakage of the electric feeders 8 and 9 due to the electric discharge, electric contact, etc., can be improved drastically.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a wire-cut electrical discharge machining device, and more particularly to a power supply device for a wire electrode.

[Prior Art] FIG. 4 is a configuration diagram showing a conventional wire-cut electric discharge machining apparatus. In the figure, (1) is the wire electrode, (2) is the wire supply bobbin, (3) is the main wire brake device that applies braking force to the running wire electrode (1), and (4) is the wire supply bobbin (2). A wire brake device applies brake force, (5) is an upper guide pulley that guides the wire electrode (1) to the processing gap, and (6) is a lower guide pulley. (7) is the workpiece to be processed. (8)
(9) is a lower feeder for feeding power to the wire electrode (1) on the upper side of the workpiece (7), (10) is the wire electrode (1) and the workpiece (
7) is an electric discharge machining power source that supplies pulsed current; (11) is a pinch roller that rotates by sandwiching the wire electrode (1) and whose speed is controlled at a predetermined rotation speed; (12) is a used wire This is a wire recovery device in which the electrode (1) is recovered.

Next, the operation will be explained. The wire electrode (1) is connected to the main wire brake device (3) and the main wire brake device (4).
), the paper is wound up by a pinch roller (11) whose rotational speed is controlled, and sent at a predetermined running speed.

On the other hand, a pulse current for electrical discharge machining is supplied between the wire electrode (1) and the workpiece (7) from the electrical discharge machining power supply (10), but since the wire electrode (1) runs during machining, the upper feeder (8) and the lower feeder (9) while sliding on the surfaces thereof.

[Problems to be Solved by the Invention] In the wire-cut electric discharge machining apparatus having the above configuration, power is supplied to the wire electrode (1) during machining by the upper and lower feeders connected to one output end of the electric discharge machining power source (10). This is done only by (8) and (9).

However, the upper and lower feeders (8) and (9) are subject to wear due to mechanical causes due to sliding with the high-tension wire electrode (1), electrical discharge due to vibration of the wire electrode (1), electrolytic corrosion, etc. There was a problem in that the surface of the feeder or the feeder itself had to be replaced frequently due to wear due to physical causes.

The present invention was made to solve the above problems,
It is an object of the present invention to provide a wire-cut electrical discharge machining device that can extend the life of a feeder, facilitate positioning of the feeder, and reduce the frequency of wire breakage near the feeder.

[Means for Solving the Problems] A wire-cut electrical discharge machining apparatus according to a first aspect of the invention includes at least one feeder connected to one of the output ends of an electrical discharge machining power source while contacting a traveling wire electrode; It is equipped with a pinch roller that rotates while pinching the wire electrode and whose rotation is controlled at a predetermined rotation speed, and the surface of the pinch roller that comes into contact with the wire electrode is a conductor, and the surface conductor part of the pinch roller and the electrical discharge machining power source are connected. The output terminal to which the feeder is connected is connected.

The wire-cut electric discharge machining apparatus according to the second invention rotates while sandwiching the wire electrode between at least one feeder connected to one of the output ends of the electric discharge machining power supply while contacting the traveling wire electrode. A bearing comprising a pinch roller whose rotation is controlled at a predetermined number of rotations, the entire pinch roller in contact with the wire electrode and the rotating shaft of the pinch roller being conductors, and the rotating shaft of the pinch roller being filled with a conductive substance. The bearing is connected to the output end to which the feeder of the electrical discharge machining power source is connected.

[Effect] During electrical discharge machining, the wire electrode vibrates slightly due to the discharge reaction force in the machining gap and the turbulent flow of pressurized machining fluid that is fed into the machining gap, and detaches from the surface of the feeder against which it is pressed. However, according to the first invention, since the wire electrode is energized not only through the feeder but also through the pinch roller that controls the running speed of the wire electrode, even if the wire electrode is detached from the surface of the feeder, The voltage and current generated in the gap are almost negligibly small, and the wear of the feeder due to electrical causes is significantly reduced.

According to the second invention, the wire electrode is energized not only through the feeder but also through the pinch roller; however, in the case where the energization to the pinch roller is through a bearing filled with a conductive substance and through the rotating shaft of the pinch roller. It will be done.

[Example] Fig. 1 is a configuration diagram of a wire-cut electrical discharge machining apparatus showing one embodiment of the first invention, and Figs. 2 and 3 show wire-cut electrical discharge machining apparatus each showing another embodiment of the first invention. It is a block diagram of a processing device. In the figure, the same reference numerals as in FIG. 4 indicate the same or corresponding parts.

(13) is a pinch roller whose surface is a conductor, (14) is a negative end that slides on the surface conductor part of the pinch roller (13), and the other end is a power supply (8) of the electric discharge machining power source (10), ( 9) is connected to the output end, which is connected to the brush, (15)
is a pool containing mercury (16), and a pinch roller (13)
) is provided in such a position that the surface conductor part of the pool (16) is in contact with or submerged in the mercury (16), and a part of the pool (15) is connected to the feeders (8) and (9) of the electric discharge machining power source (10). connected to the output end. (17) is the pinch roller (1
3) is the rotation axis.

Usually, the upper and lower feeders (8) and (9) are wire electrodes (
Since the wire electrode (1) is placed in a position slightly eccentric from the center of the guide (not shown), the wire electrode under tension (
1), power is supplied by pressing the power supply electrons (8) and (9) from one side in a tight manner. However, the wire electrode (1) vibrates slightly due to the discharge reaction force in the machining gap during electrical discharge machining and the turbulent flow of pressurized machining fluid (not shown) that is fed into the machining gap, and the wire electrode (1) vibrates slightly. ),
(9) Detach from the surface.

In the configuration shown in Fig. 1, the running wire electrode (1) includes upper and lower feeders (8) and (9) as well as a pinch roller (13).
) is also supplied with power from the electric discharge machining power source (10) through the surface conductor portion of the wire electrode (1), and the wire electrode (1) sandwiched between the pinch rollers (13) will not come off even if there is vibration. Therefore, the wire electrode <1) is the feeder (8),
(9) Even if it detaches from the surface, the wire electrode (1)
The voltage and current generated between the feeder (8) and (9) are significantly reduced compared to the case where only the feeder (8) and (9) are used. 8), (9)
Surface damage is significantly improved.

In the configuration shown in FIG. 2, power is supplied to the surface conductor portion of the pinch roller (13) via a brush (14) that slides on the surface of the pinch roller (13), which further improves the first invention. It can be easily achieved.

In the configuration shown in FIG. 3, power is supplied to the surface conductor portion of the pinch roller (13) via the mercury pool (15), and the first invention can be achieved more reliably.

In addition, the pinch roller (13) and its rotating shaft (
17) is entirely made of a conductor, and a bearing (not shown) that supports the rotating shaft (17) is filled with a liquid metal such as mercury or a conductive substance such as conductive powder, and this bearing is further processed by electrical discharge machining. In an embodiment according to the second invention, the pinch roller (13) is electrically connected to the output end to which the feeders (8) and (9) of the power source (10) are connected. The entire device can be made compact without requiring any special equipment outside the device.

[Effects of the Invention] According to the first invention, power is supplied to the wire electrode not only by the feeder but also through the pinch roller that rotates while pinching the wire electrode, which reduces the discharge reaction in the machining gap during discharge machining. Even if the wire electrode separates from the feeder surface due to minute vibrations of the wire electrode due to force or turbulent flow of machining fluid, the voltage generated between the wire electrode and the feeder at that time,
The current is significantly reduced compared to the conventional one, and therefore damage to the feeder surface due to discharge and electrolytic corrosion is significantly reduced, making it possible to extend the life of the feeder. Furthermore, regarding the squeezing angle of the wire electrode with respect to the feeder, there is no need for more delicate adjustment than in the past, making positioning of the feeder easier. Furthermore, since the frequency of occurrence of discharge and electrolytic corrosion is reduced, the frequency of wire breakage near the feeder can also be reduced.

According to the second invention, the electrical discharge machining power source is connected to the pinch roller by using the entire pinch roller and the rotating shaft of the pinch roller as conductors, and using a bearing that supports the rotating shaft and has a conductive substance sealed inside. Since this method eliminates the need for special external equipment, the entire device can be made more compact.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing one embodiment of the first invention, Figs. 2 and 3 are block diagrams showing different embodiments of the first invention, and Fig. 4 is a conventional wire cut discharge. It is a block diagram of a processing device. In the figure, (1) is a wire electrode, (8) is an upper feeder, (9) is a lower feeder, (10) is an electrical discharge machining power supply, and (1) is a wire electrode.
3) is a pinch roller with a conductive surface, (14) is a brush,
(15) A pool of mercury. (17) is the rotating shaft of the pinch roller. In each figure, the same reference numerals indicate the same or corresponding parts.

Claims (2)

[Claims] (1) At least one feeder connected to one of the output ends of the electric discharge machining power supply while contacting the running wire electrode, rotating while sandwiching the wire electrode, and controlling the rotation at a predetermined rotation speed. a pinch roller, the surface of the pinch roller that comes into contact with the wire electrode is a conductor, and the surface conductor portion of the pinch roller is connected to an output end of the electric discharge machining power source to which the feeder is connected. A wire cut electric discharge machining device characterized by the following. (2) At least one feeder connected to one of the output ends of the electrical discharge machining power supply while contacting the running wire electrode, rotates while sandwiching the wire electrode, and the rotation is controlled at a predetermined rotation speed. the entire pinch roller in contact with the wire electrode and the rotating shaft of the pinch roller are conductors, and the rotating shaft of the pinch roller is supported by a bearing filled with a conductive substance; A wire-cut electric discharge machining apparatus, characterized in that a bearing is connected to an output end of the electric discharge machining power source to which the feeder is connected.