JPH0545370B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Application of the Invention) The present invention relates to an improvement in a wire-cut electric discharge machining apparatus that performs electric discharge machining using a thin wire as an electrode.

[Prior art and problems]

Conventionally, the wire electrode is energized by contacting it with an energizing pin. Since only one current-carrying pin is provided on one side of the workpiece, the contact area is small and the current-carrying loss is large. Another disadvantage is that the arc generated between the wire electrode and the workpiece extends for a long time, overheating the wire electrode and causing wire breakage.

[Means for solving problems]

The present invention was proposed in view of these points,
A plurality of current-carrying pins are provided along the moving direction in contact with the moving wire electrode, and at least one of the current-carrying pins closest to the workpiece is arranged opposite to each other with the wire electrode sandwiched therebetween. It is characterized by letting you do it.

〔Example〕

The present invention will be described below with reference to an embodiment of the drawings. Reference numeral 1 denotes a wire electrode, which is supplied from a reel (not shown), guided, and runs and moves with a predetermined tension and speed. Reference numeral 2 denotes a workpiece, which faces the wire electrode 1 and forms a machining gap, and performs electrical discharge machining by repeating pulsed discharge. 31, 32, 33, 34 are a plurality of current-carrying pins arranged along the moving direction and in contact with the wire electrode on the upper side of the workpiece;
Reference numerals 43 and 44 denote a plurality of current-carrying pins that are arranged along the moving direction and in contact with the wire electrode on the lower side of the workpiece. 31 and 32, 4 facing each other in between
1 and 42. Each energizing pin is 31, 32 and 4
1, 42, 33 and 43, and 34 and 44 are connected as a pair and connected to a power source. Reference numeral 7 denotes a processing power source, which is connected to each of the current-carrying pins through respective shunt circuits 51, 52, and 53. 61, 62, 63 are switches and resistors inserted in each shunt circuit, and the shunt circuit 51 of the current-carrying pins 31, 41 closest to the workpiece 2
Each switch 61,
62 and 63 adjust the impedance to equalize the current values flowing from each shunt circuit through each current-carrying pin.

In the above process, the wire electrode 1 and the workpiece 2, which move with a predetermined tension and speed, are faced and processed. Machining fluid is supplied from a nozzle (not shown) between the opposing surfaces, and pulse discharge is repeated to perform machining. During machining, a relative machining feed of the machining shape is applied to the workpiece 2 by an NC control device (not shown), and a wire cut with a predetermined contour shape is performed. For pulse discharge, switch 61,6
2 and 63 are turned on and off simultaneously or by phase difference control.
The DC current from the power supply 7 is transferred from the shunt circuits 51, 52, 53 to the respective energizing pins 31, 32, 53.
It is supplied in pulses through 33, 34, 41, 42, 43, and 44, and pulse discharge is repeated. The current flowing through each of the shunt circuits 51, 52, and 53 is matched so that the shunt current flows equally according to each distance from the discharge part of the current-carrying pin, and the current flows in a concentrated manner in some of the current-carrying pins. Never happened. Therefore, since the current is divided into multiple parts and passed through each current-carrying pin, the current-carrying contact area of the current-carrying pin increases accordingly, which reduces heating loss at the contact area between each current-carrying pin and the wire electrode. Able to conduct electricity with high efficiency. Moreover, since overheating is prevented, stable electric discharge machining can be performed with less disconnection of the wire electrode. In addition, multiple energizing pins are installed in parallel,
Since the discharge current is equally distributed to each pin for power supply, the consumption of the current-carrying pins is reduced to a factor of 1/2 compared to the number of parallel pins, and the service life can be significantly increased.
Then, the wire electrodes 1
Since the arc discharge generated in the machining area opposite to the workpiece 2 develops along the wire electrode 1 and is made to face each other, the shortest position above and below the workpiece 2 This can be interrupted by opposing current-carrying pins 31, 32 and 41, 42 arranged in the same direction. Therefore, it is possible to prevent wire breakage due to heating of the wire electrode 1 by this arc, prevent evaporation of the supplied machining fluid, increase the amount of cooling fluid supplied to the machining part, and improve electrical discharge machining performance.

〔effect〕

As explained above, in the present invention, a plurality of current-carrying pins are provided along the moving direction in contact with a moving wire electrode, and the discharge current is shunted from the machining power source to conduct electricity, so that the current-carrying contact area is reduced. increases, reduces heat loss, and enables highly efficient current conduction.
It is possible to stably supply large current by increasing the peak value without distorting the waveform, making it easy to perform high-speed machining. Moreover, breakage of the wire electrode due to overheating can be prevented, and stable and efficient electrical discharge machining can be performed. In addition, by dividing the current, the consumption of each current-carrying pin can be reduced, and the life of the pin can be increased. or,
Of the multiple current-carrying pins, the one closest to the workpiece is configured with a pair of current-carrying pins that are placed opposite each other with a wire electrode in between, so that the arc that is transmitted through the wire electrode from the area between the machining areas can be avoided. This has the effect of preventing heating and disconnection of the wire electrode due to the progressing arc, and preventing vaporization of the supplied machining fluid to enhance the cooling effect and increase the machining speed.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of an embodiment of the present invention. 1... Wire electrode, 2... Workpiece, 31, 3
2, 33, 34, 41, 42, 43, 44... energizing pin, 51, 52, 53... shunt circuit, 61,
62, 63...Switch, 7...Processing power supply.

Claims (1)

[Claims] 1. A wire electrode traveling between guides and a workpiece are faced to each other via a machining gap, and a pulse discharge is repeatedly generated between the wire electrode and the workpiece while machining fluid is supplied to the machining gap. In a wire-cut electrical discharge machining device that performs machining of a desired contour shape by applying a relative machining feed while giving a relative machining feed, a plurality of energizing pins that contact the wire electrode and energize are installed in the travel path of the wire electrode on both sides of the workpiece. At least one of the plurality of current-carrying pins located closest to the workpiece is constituted by a pair of current-carrying pins that are arranged opposite to each other with a wire electrode in between. Wire cut electrical discharge machining equipment.