JPS603531B2 - Electric discharge machining equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is an electric discharge method in which a DC power source is turned on and off using a switch such as a transistor to generate machining pulses, and the generated pulses are supplied to the machining gap between the power source and the workpiece to perform machining. Concerning the improvement of processed diamond counterfeiting.

To connect a machining pulse power source to the machining gap between the electrode and the workpiece, a long cable is used to connect the mechanical device and the power source, which are usually constructed separately. However, due to the inductance and resistance of the cable, electrical discharge The disadvantage is that the wave height cannot be increased.

The present invention has been proposed in view of this drawback, and includes providing a capacitor and a discharge control switch near the gap in a machining gap connected to a pulse power source, and a pulse power source that controls the capacitor and discharge control switch. A capacitor discharge circuit comprising a generating circuit is connected in parallel to the machining gap, and a capacitor charging circuit comprising a rectifier in the charging direction of the capacitor is connected in series between the machining gap and the capacitor. The present invention will be explained below with reference to an embodiment of the drawings.

In FIG. 1, 1 is a machining electrode, 2 is a workpiece, and they face each other to form a machining gap. Reference numeral 3 constitutes a DC power source obtained by rectifying a commercial current exposure source, 4 a transistor switch, 5 a pulse generation circuit that generates switch control pulses, and a pulse power source that generates processing pulses by on/off switching of the switch 4.

This pulse power source is connected to the machining gap via a cable 6. 7 is a discharge capacitor, 8 is a discharge control switch,
At least these two 7, 8 are arranged near the machining gap,
The lead wire is shortened and connected to the machining gap.

Reference numeral 9 denotes a generating circuit for generating switch 8 control pulses, which together with the capacitor 7 and switch 8 constitutes a capacitor discharge circuit. The pulse generating circuit 9 is connected to the pulse generating circuit 5 so as to be controlled in conjunction with the pulse generating circuit 5, but may operate independently.

The processing pulse power source generates processing pulses by controlling the on/off switching of the switch 4, thereby generating a processing pulse train. Although the generated pulses are supplied to the machining gap through the cable 6, machining is not directly performed by these machining pulses. A capacitor 7 is provided in the machining gap, and the supplied machining pulse is connected to a rectifier 10.
The capacitor 7 is charged through the capacitor 7. When the switch 8 is turned on, the capacitor 7 is discharged through the switch 8 into the machining gap. Since the capacitor 7 is disposed near the machining gap and connected with a short lead wire, it is possible to discharge a pulse with an increased peak value lp. That is, the peak value lp is expressed as lp=V, and 7 in the pulse is expressed as 7=Lamp.
is configured to be as small as possible and less than IAH, and according to actual measurements, it is approximately 0.
．． It was the 3rd French day.

Therefore, depending on the capacitor capacity, it becomes as follows. 1
．． In the case of 5F, 0.3rH, 90V, D=〇. 7 mountains Sec? lp=200A I. In the case of French F, 0.3rH, 90V, 7 d 0.5 French Sec, 1p: 15 mountains A O. 5F, 0.2rH, 90V Keni ○. 3 peaks Sec,lp=140A By inserting the capacitor discharge circuit near the machining gap in this way, the waveform of the machining pulse supplied from the machining pulse power source is converted into a pulse with increased peak value, and the waveform is discharged into the machining gap. be able to.

The oscillation frequency of the pulse generation circuit 9 is normally set to about 1 to 10 KHz, but if it is controlled in synchronization with the pulse generation circuit 5 of the machining pulse power source, all machining pulses supplied from the machining pulse power source are capacitor discharged. If the circuit converts the waveform into a pulse with increased peak value and discharges, and if the switch 8 is controlled on/off at a frequency lower than the repetition frequency of the supplied machining pulse, then the machining pulse train will have less It is possible to perform a pulsed discharge that incorporates a pulse that increases the peak value by a certain percentage.

Of course, if the capacitor capacity of the peak value increasing pulse due to capacitor discharge is sufficiently small compared to the supplied machining pulse, the discharge will have a waveform such that the peak value increasing pulse is superimposed on the machining pulse. In this way, the machining speed is significantly improved by converting the waveform of the machining pulse supplied from the machining pulse power source by the capacitor discharge provided near the machining gap and discharging the wave height increasing pulse.

That is, the servo-controlled machining gap can be widened by converting the electric discharge into a pulse with increased peak value or by incorporating the pulse with increased peak value into the machining pulse. As a result, the machining shoulder removal effect is improved, and passivated materials such as machining debris in the machining gap are removed.
It is possible to melt and remove the discharge peaks etc. on the surface of the workpiece.
The electric discharge is stabilized in a pulsed manner, and arcs and the like are no longer generated. Therefore, this stable machining improves the machining speed. For example, according to experiments, when the pulses supplied from the processing pulse power source are 90V, 720F sec, and 50A pulses, and when processing Fe material with an Fe material electrode, a 1F capacitor is placed near the processing gap. When the discharge circuit is connected with an inductance of 0.3 and the switch inserted in the discharge circuit is turned on and off synchronously with the processing pulse supplied from the pulse power source to perform capacitor discharge, The processing speed increased to about three times that of the case without a capacitor connected, and the electrode consumption ratio E/W was 3%.

Note that the E/W when no capacitor was provided was 18%. In this way, it was confirmed that the machining speed was significantly improved simply by providing a discharge-controlled capacitor near the machining gap. FIG. 2 shows a modified example, and parts with the same symbols as those in FIG. 1 indicate the same parts.

In this circuit, the capacitor 7 is connected to the machining gap via the switch 8, and connected to the machining pulse power source via the rectifier ID, so that there is no discharge in the machining gap due to direct machining pulses other than capacitor discharge. All of the discharge occurs in the machining gap by capacitor discharge.The pulse generation circuit 9 operates using the charging and dew pressure of the capacitor 7 as a signal, and every time the required charging is performed, it emits a control pulse and turns on the switch 8 to discharge. With this circuit device, the capacity of the capacitor 7 is set for the machining pulse energy supplied from the pulse power source so that one discharge is performed per pulse, so that each machining pulse becomes a peak value increasing pulse. The machining speed can be increased by converting the waveform into electric discharge and increasing the wave height value.

In FIG. 3, the processing pulse voltage is detected by the detection resistor 11, and the output control pulse of the pulse generation circuit 9 activated by this detection signal and the charging pressure of the capacitor 7 is AND gated! 2
The switch 8 is connected to control the switch 8, and the switch 8 is turned on and capacitor discharge is performed only when processing pulses are being supplied from the pulse power source. In this case, the discharge waveform of the machining gap is such that the capacitor discharge is superimposed on the machining pulse, and the timing of the capacitor discharge can be arbitrarily controlled by controlling the phase difference of the pulse generating circuit 9. FIG. 4 shows a capacitor discharging circuit comprising a plurality of capacitors, switches, pulse generating circuits, etc., which is controlled by a ring counter 13 or the like so as to sequentially discharge the capacitor.

In FIG. 5, a charging power source 14 is inserted so as to be superimposed on the machining pulse supplied to the charging circuit of the capacitor 7, thereby accelerating the charging speed and making it possible to charge to a higher voltage than the machining pulse.

The capacitor discharge circuit in each of the above embodiments can be housed in one case and configured compactly by connecting the output terminal to the machining gap.

It should be noted that discharge circuits with various circuit configurations other than the above embodiments can be used, but the waveform of the machining pulse is converted into a pulse height increasing pulse by a capacitor discharge, and the pulse is discharged into the machining gap. Because
The wave height value can be easily increased, and the processing speed can be significantly improved.

[Brief explanation of drawings]

FIG. 1 is a circuit configuration diagram of an embodiment of the present invention, and FIGS.
The figure is a circuit configuration diagram of another embodiment. 1 is an electrode, 2 is a workpiece, 3 is a DC power source, 4 is a switch, 5 is a pulse generation circuit, 6 is a cable, 7 is a capacitor, 8 is a switch, 9 is a pulse generation circuit, and 1 is a rectifier. O” Nezumi 21 Mist O 31 Cheek Spear 4 Nezumi O 5 Nezumi

Claims (1)

[Claims] 1 A pulse power source consisting of a DC electrode, an on/off switch, and a pulse generation circuit that controls the switch is connected to the machining gap between the machining electrode and the workpiece by a cable, and a capacitor and a discharge switch are installed near the machining gap. A capacitor discharge circuit consisting of the capacitor, a discharge switch, and a pulse generation circuit for controlling the switch is connected in parallel to the machining gap, and a capacitor charging circuit consisting of a rectifier in the charging direction of the capacitor is connected to the machining gap. An electric discharge machining device characterized by connecting capacitors in series.