JPS6190824A - Electric discharge machine - Google Patents

Abstract

PURPOSE:To promote discharge of unnecessary material in tank thus to improve the maintenancability by producing uncombustible foam in the liquid on the basis of a detection signal of unnecessary material produced more than predetermined amount in machining tank under machining. CONSTITUTION:Upon accumulation of unnecessary conductive material 200 on the bottom of machining tank to shortcircuit between detectors 206a, 206b for starting timer, a timer 201 will start to open a solenoid valve 202 for setting time. Consequently, uncombustible gas in a cylinder 203 will flow through a solenoid valve 202 and a piping 204 for uncombustible gas and eject through a small hole 205a of foam generator 205 into the working liquid to produce foam which is dispersed into the machining tank. Here, unnecessary material 200 accumulated around the small hole is dispersed into insulative working liquid to lower the apparent specific gravity of insulative working liquid mixed with foam and the unnecessary material 200 thereby the unnecessary material will ride easily on the discharge flow to be discharged quickly to the outside. Consequently, electric discharge machining is stabilized while maintenancability is improved.

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention relates to an electric discharge machining apparatus, in particular, an electrode and a workpiece that are opposed to each other in a machining tank with an insulating machining fluid interposed between them, and a The present invention relates to an electric discharge machining apparatus that processes a workpiece by generating electric discharge.

[Conventional technology]

FIG. 2 is a schematic configuration diagram showing a conventional electrical discharge machining device.
In the figure, an electrode 10 faces a workpiece 14 placed in a processing tank 12 with an insulating processing liquid 16 in between. A processing power source 18 is connected between the electrode 10 and the workpiece 14.

This machining power source 18 is composed of a DC power source 18a, a switching element 18b for controlling the machining current on and off, a current limiting resistor 18C, and an oscillator 18d for controlling the on/off of the switching element 18b. The electrode 10 and the workpiece 14 are intermittently supplied to the gap 20 between opposing electrodes.

The machining current I is expressed by the following formula: I = 1 - (E is the voltage value of the DC power supply 18a, R is the resistance value of the current limiting resistor 18C, and Vg is the voltage between electrodes). The interelectrode voltage value vg is 20 to 30v during arc discharge.

The voltage is Ov during a short circuit, EV during no discharge, and Ov when the switching element 18b is off.

Therefore, if this inter-electrode voltage value Vg is detected and averaged by the smoothing circuit 22, the inter-electrode gap control can be performed using this value. In other words, when the gap between the poles is wide, discharge tends to occur (
Therefore, the average voltage value Vs is high.

When the gap between the electrodes is narrow, a short circuit occurs or discharge occurs easily, so that the average voltage value v5 decreases. Therefore, this average voltage value vs
is compared with the reference voltage value vr, and this difference is amplified by the amplifier 24 and inputted to the hydraulic servo coil 26. The electrode 10 can be controlled so that

[Problem that the invention seeks to solve]

In the above-mentioned conventional electric discharge machining equipment, when the workpiece is machined by the arc discharge generated between the electrode and the workpiece, unnecessary materials such as machining powder and sludge generated by this machining are removed. It was dispersed in the insulating machining fluid in the tank, and was discharged out of the machining tank at the same time as the insulating machining fluid was discharged. However, due to factors such as the shape and arrangement of the workpieces and the size of the machining tank, the insulating machining fluid may accumulate, and the above-mentioned unnecessary materials accumulate in the machining tank, causing periodic There was a problem in that it was necessary to clean the

This invention was made in order to solve such problems, and an object of the present invention is to provide an electrical discharge machining device that can promote the discharge of unnecessary materials in the machining tank and improve the maintainability of the machining tank. do.

[Means for solving problems]

This electric discharge machining apparatus according to the present invention includes a detection means for detecting that a certain amount or more of unnecessary materials generated during machining has accumulated in a machining tank and outputting a signal, and a detection means for outputting a signal based on the output signal from the detection means. A bubble generating means is provided for generating bubbles of non-flammable gas in the machining liquid to promote discharge of the above-mentioned unnecessary substances.

[Effect]

In this invention, when the detection means outputs a signal indicating that a certain amount or more of unnecessary matter has accumulated in the machining tank, the bubble generation means generates bubbles in the machining fluid based on this signal. These air bubbles reduce the specific gravity of the machining fluid, allowing unnecessary materials to be smoothly discharged out of the machining tank.

〔Example〕

FIG. 1 is a sectional view showing an embodiment of the present invention, and the same parts as in FIG. 2 are given the same reference numerals.

In FIG. 1, 203 is a cylinder of nonflammable gas;
Processing tank 1 is connected via electromagnetic pulp 202 whose opening and closing are controlled by the output of timer 201 and nonflammable gas piping 204.
2 is connected to a bubble generator 205 provided at the bottom.

206a and 206b are detectors for starting the timer 201 as detection means made of conductive electrodes, and are installed at a certain distance apart at the bottom of the processing tank, and a timer drive power source 201a is connected to one of them. There is. 200
are unnecessary materials such as processing powder and sludge that have accumulated at the bottom of the processing tank. Reference numeral 110 denotes a pipe for discharging the insulating machining fluid, the discharge end of which opens at the top of the storage tank 99 for the machining fluid 16. This storage tank 99 is connected to the processing tank 1 by a processing fluid supply pipe 103.
2, and in the middle of this supply pipe 103 is a pump 1 that supplies the machining fluid 12 from the storage tank 99 to the machining tank 12.
00 is set.

The workpiece is cut by arc discharge in the minute gap between the electrode 10 and the workpiece 14 facing the electrode 10, and at the same time, unnecessary materials 200 such as machining powder and sludge are generated. These unnecessary substances are dispersed in the insulating machining fluid 16, and a portion passes through the machining fluid discharge pipe 110 and is discharged together with the insulating machining fluid.

However, since the specific gravity of the unnecessary material 200 is higher than that of the insulating machining fluid, most of it is not discharged and settles at the bottom of the machining tank 12. Unholy matter 200, which is a conductive substance, accumulates at the bottom of the processing tank, and the timer activation detectors 2062, 2
When 06b is short-circuited, the timer 201 is started and the electromagnetic pulp 202 is opened for a preset time. Therefore, the nonflammable gas stored in the cylinder 203 is guided to the bubble generator 205 through the electromagnetic pulp 202 and the nonflammable gas pipe 204, and processed through the small hole 205a made in the bubble generator 205. It squirts into the liquid, becomes bubbles, and disperses within the processing tank. At this time, at the same time, unnecessary materials 200 accumulated around the small holes are dispersed into the insulating working fluid. Insulating processing with non-flammable gas bubbles and the above-mentioned unnecessary materials 200 At night, the apparent specific gravity is lighter than when there are no bubbles, and the above-mentioned unnecessary materials are more likely to follow the flow of discharging the non-flammable machining fluid. and is immediately discharged out of the processing tank.

In the above embodiment, the timer is started according to the output of the timer start detector and the electromagnetic pulp is controlled for a preset time. It has the same effect as the example.

〔Effect of the invention〕

As described above, according to the present invention, it is detected that a certain amount or more of unnecessary substances such as sludge generated by electrical discharge machining has accumulated at the bottom of the machining tank, and air bubbles are generated in the machining fluid.
Since the discharge of the above-mentioned unnecessary substances is promoted, machining during electrical discharge machining can be stabilized. Additionally, there is no need to periodically remove unnecessary materials accumulated at the bottom of the processing tank, resulting in improved maintainability.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention, and FIG. 2 is a principle diagram showing a conventional electrical discharge machining apparatus. 10 is an electrode, 12 is a processing tank, 14 is a workpiece, 16 is an insulating processing liquid, 206a and 206b are detection means (starting detector), and 205 is a bubble generation means (bubble generator). In addition, in the figures, the same reference numerals indicate the same or equivalent parts 1-0 Patent applicant Mitsubishi Electric Corporation Procedural amendment (voluntary)

Claims (1)

[Claims] In an electric discharge machining apparatus that processes the workpiece by disposing an electrode and the workpiece facing each other in a machining tank with an insulating machining fluid interposed therebetween, and generating electric discharge between the electrode and the workpiece, the workpiece is a detection means for detecting that a certain amount or more of unnecessary materials generated during processing has accumulated in the processing tank and outputting a signal; and a detection means for outputting a signal based on the output signal from the detection means An electrical discharge machining apparatus comprising: a bubble generating means for generating bubbles of nonflammable gas to promote discharge of the unnecessary substances.