JPS60180725A - Discharge machining power supply - Google Patents

Abstract

PURPOSE:To allow the positive and negative voltage to be applied across a work and an electrode with a simple circuit by turning on or off a switching element connected in parallel with a serial circuit of a capacitor, the electrode and the work. CONSTITUTION:When a DC power supply E is turned on, the voltage VG is applied across a gap between an electrode P and a work W due to a closed circuit with the electrode P connected to the positive side and the work W to the negative side, then a capacitor C is charged by a leak current, and the charge voltage VC is generated with the electrode P side made negative and a transistor side positive. Next, when a pulse is applied to the base G of the transistor T to turn it on, the charge voltage VC of the capacitor C is applied across the work W and the electrode P. In this case, on the contrary the gap voltage VG is applied with the work W side made positive and the electrode P side negative, then a discharge occurs between the work W and the electrode P, and the charge stored in the capacitor C flows as a discharge current I between the work W and the electrode P to perform discharge machining. Accordingly, the positive and negative voltage can be applied.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application and Prior Art The present invention relates to an electric discharge machining power source that applies positive and negative voltages between a workpiece and an electrode in electric discharge machining.

Prior Art and Purpose of the Invention In electric discharge machining, when an electrolytic machining fluid such as water is used, electrolysis occurs. In particular, when rough machining a workpiece that is susceptible to electrolytic corrosion, such as cemented carbide, electrolytic corrosion occurs, making the workpiece brittle.

In addition, during the second cut, the surface of the workpiece becomes rough due to selective electrolytic corrosion of particles due to the electrolytic action, resulting in poor finished surface roughness.

It is known that these drawbacks can be improved by applying a reverse voltage to the V-tube between the electrode and the workpiece during non-machining, contrary to that during machining, and various methods exist, but the present invention The present invention aims to provide an electric discharge machining power source that can apply positive and negative voltages between the workpiece and the electrode through an internal circuit. In the electrical discharge machining power supply for electrical discharge machining, a series circuit consisting of a resistor and a resistor connected in series with the electrode and the workpiece is connected to a DC power supply, and the series circuit of the conductor and the resistor is switched in parallel with the series circuit of the electrode and the workpiece. This electrical discharge machining power supply is configured so that an iL-negative voltage can be applied between the electrode and the workpiece by connecting elements and turning the switching element on and off.

Embodiment FIG. 1 shows an embodiment of the present invention, where E is a DC power supply, R is a current limiting resistor, T is a transistor as a switching element, G is the base of the transistor, C is a capacitor, and P is an electrode. , W is the workpiece.

Therefore, the operation of this embodiment will be explained with reference to FIG. 2 which shows the timing and each waveform.

When the DC power supply E is turned on, a closed circuit of the DC power supply E, the resistor R, the capacitor C1 electrode P, the work W, and the DC power supply E creates a gap between the electrode P and the work W as shown in Fig. 2 (C). A gap voltage Va is applied. In this case, a voltage is applied to the electrode P on the plus side and the workpiece W on the minus side. Thereafter, the capacitor C is charged by the leakage current between the electrode P and the workpiece W, as shown in FIG. 2 (b).

Electrode P side is negative, resistor R1 or transistor T
A charging voltage Vc with a positive connection side is generated. In this state, when the transistor T is turned on by applying a pulse as shown in FIG. is applied between the electrodes 8 and 8. In this case, as shown in Fig. 2 (c), the work W
A gap voltage Va in which the side of the electrode P is positive and the side of the electrode P is negative is applied. After that, a discharge occurs between the workpiece W and the electrode 8, and the charge stored in the capacitor C becomes a discharge current I through the transistor T as shown in FIG. Perform flow discharge machining. Then, when the transistor T is turned off, the voltage returns to 1. ．． A reverse voltage VO, which is opposite to that during machining, is applied between P and work W as shown in Figure 2 (c), and the same operation as described above is performed, and this operation is repeated to perform electrical discharge machining. be exposed.

Effects of the Invention As described above, the present invention makes it possible to apply positive and negative voltages between the electrode and the workpiece using a simple circuit.
Electrolytic corrosion of the workpiece can be prevented even in electrical discharge machining using an electrolytic machining fluid such as water.

[Brief explanation of the drawing]

FIG. 1 is a diagram that does not show one embodiment of the present invention, and FIG. 2 is a diagram that shows the timing and each waveform of the same embodiment. 1st: DC power supply, T... switching element, C...
...Condenser υ, R...Resistance, P...Electrode, W...
·work. Special 51 applicant FANUC Co., Ltd. (1 idiot) Figure 1 Figure 2

Claims (1)

[Claims] In the electrical discharge machining power supply for electrical discharge machining, in which a voltage is applied between the electrode and the workpiece to cause discharge, a series circuit consisting of a capacitor υ and a resistor connected in series with the electrode and the workpiece is connected to a DC power supply, and the capacitor and the An electrical discharge machining power supply in which a switching element is connected in parallel with a series circuit of an electrode and a workpiece, and positive and negative voltages are applied between the electrode and the workpiece by turning on and off the switching element.