JPH05212628A - Electric discharge machine - Google Patents

Abstract

PURPOSE:To provide an electric discharge machine capable of confirming a proper liquid amount in a working liquid supply device corresponding to a liquid level in a working tank even during working and provided with a control ler for detecting the shortage of the liquid amount to replenish the liquid to the proper liquid amount. CONSTITUTION:A liquid level indicator 30 capable of judging the proper liquid level of contaminated liquid corresponding to a set value of any liquid level in a working tank 1 is provided in a contaminated liquid tank 21 of a working liquid supply device 50. A liquid level detecting sensor for judging a detrimental amount of the working liquid is mounted in the working liquid supply device 50, and a controller is provided which opens and closes a solenoid valve provided in a working liquid replenishing pipe on the basis of the output value of the liquid level detecting sensor to replenish the working liquid.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric discharge machining apparatus of the immersion type, and more particularly to a machining liquid level detecting apparatus and a machining fluid supply apparatus for the electric discharge machining apparatus.

[0002]

2. Description of the Prior Art Most conventional wire electric discharge machining apparatuses have been of a spray type in which the machining fluid is sprayed from the upper and lower nozzles to the wire without filling the machining tank with the machining fluid. However, in recent years, objects to be processed have diversified,
Wire electric discharge machining has come to be performed even in the machining of parts with complicated shapes.In that case, a dipping type wire electric discharge machine that fills the machining tank with the machining liquid and dips the workpiece in the machining is used. It

FIG. 8 is a schematic view showing a general wire electric discharge machining apparatus of immersion specification. In the figure, 1 is a processing tank in which a processing liquid is stored, and 2 is a table for fixing a work, which is installed in the processing tank 1. Reference numeral 3 denotes a work fixed to the table 2, and a wire electrode 4 to which a voltage is applied between the work 3 and the work 3 while traveling through the work 3.
Is processed by. Then, the processing tank 1 is moved forward, backward, leftward and rightward in the drawing by a command from the control device 5 based on the operator's input data, and the work 3 is processed into a desired shape. Reference numerals 6 and 7 denote upper and lower wire guide portions that regulate the position of the wire electrode 4, respectively.
A nozzle for injecting the working liquid is provided at the inlet / outlet portion of the. Reference numeral 8 is a lower arm connected to the lower wire guide 7, and has a pipe for guiding the traveling path of the wire inside, and the wire electrode 4 is recovered after traveling inside the lower arm 8. A Z-axis device 9 regulates the position of the upper wire guide 6 in accordance with the height of the work by a command from the control device 5 based on the input data of the operator.

Reference numeral 10 is a liquid level setting device for the machining liquid, which is attached adjacent to the machining tank 1, and a communication port (not shown) for communicating with the machining tank 1 is provided in the lower part of the leveler. Processing tank 1 and liquid level setting device 1 via this communication port
The liquid level of 0 becomes the same. Reference numeral 11 denotes a knob screw for liquid level setting, which is attached to the side wall of the liquid level setting device 10 so as to partially penetrate the liquid level setting device 10. When the screw is loosened, it can be moved up and down and can be set at an arbitrary height. Reference numeral 14 denotes a tubular bellows which is disposed inside the liquid level setting device 10 with a certain gap, the upper end of which is fixed to the end of the knob screw 11 and the lower end of which is attached to the valve 12 described later. There is. Reference numeral 12 is a box-shaped valve that is installed inside the liquid level setting unit 10 and opens and closes a discharge port 13 provided at the bottom of the liquid level setting unit 10. By opening this valve 12, the bellows 14 and the liquid are opened. The machining fluid stored in the gap of the surface level setting device 10 can be discharged. Further, the valve 12 is provided with a hole penetrating from the upper surface to the lower surface, and the working fluid overflowing the bellows 14 is discharged from the discharge port 13 through the inside of the bellows 14 and the through hole of the valve 12.

Reference numeral 50 denotes a machining liquid supply device, which is a machining liquid tank 20 for storing the machining liquid, a sewage tank 21 for storing the sewage discharged from the discharge port 13 of the machining tank 1 in the machining liquid tank 20, Similarly, a clean fluid tank 22 for storing the clean fluid to be supplied to the machining tank 1 in the machining fluid tank 20, a machining fluid supply pump 23 for supplying the clean fluid stored in the clean fluid tank 22 to the machining tank 1, The filter pump 25 is installed in the clean liquid tank 22.
It is composed of a filter 24 for filtering the waste liquid sent by. During processing, the processing liquid supply pump 23
Supplies clean liquid also to the wire guide portions 6 and 7, and the clean liquid is jetted from a jet nozzle installed therein and stored in the processing tank 1. Reference numeral 26 denotes a liquid level indicator for indicating the liquid level of the waste liquid tank 21, which is a float 27 that moves up and down as the liquid level moves up and down, and a guide member fixed at one end to the float 27 and fixed to the upper surface of the machining liquid tank 20. The indicator rod 29 is vertically movably guided and supported by the reference numeral 60, and the indicator scales 28a and 28b displayed on the indicator rod 29. The instruction scale 28a is set so as to indicate the upper surface of the guide member 60 when the working fluid is not supplied to the working tank 1 at all (hereinafter referred to as "steady state") and the working fluid has an appropriate amount. The scale 28b is set so as to indicate the upper surface of the guide member 60 when the filter pump 25 is the minimum allowable liquid surface that does not suck air.

Next, the operation will be described. Before the processing is started, the processing liquid is in a steady state as shown in FIG. 9, and the processing liquid supply pump 23 is stopped. In this steady state, the filter pump 25 is operating, the waste liquid is sent to the clean liquid tank 22 and filtered by the filter 24, and the clean liquid overflowing the clean liquid tank 22 flows into the clean liquid tank 21. By this circulation, the working fluid soiled by the processing is regenerated into the clean fluid. Since the supply capacity of the filter pump 25 is designed to be larger than that of the processing liquid supply pump 23, the clean liquid tank 22 will be filled with water as in the steady state if the filter pump 25 is operated even during processing. Is becoming During the processing, the processing liquid supply pump 23 operates to supply the cleaning liquid in the cleaning liquid tank 22 to the processing tank 1. In the processing tank 1, the liquid level is set by the knob screw 11 according to the height of the work, and the processing liquid exceeding the set value is discharged from the discharge port 13 and returned to the waste liquid tank 21. After the processing is completed, the valve 12 is opened and the processing liquid is all returned to the waste liquid tank 21.

The machining liquid tank 20 has a predetermined amount of the machining liquid in a steady state, that is, the indicator scale 2 of the liquid level indicator 26.
An amount that 8a indicates the upper surface of the guide member 60 is inserted. The entire amount of this liquid can be stored in the processing liquid tank 20, and even if the liquid level of the processing tank 1 is maximized as shown in FIG. 10, the liquid level of the waste liquid tank 21 is lower than the suction port of the filter pump 25. It is set not to become. Waste tank 2
When the liquid level of 1 is lower than the suction port of the filter pump 25, the filter pump 25 may suck air, which may cause a failure. This is indicated by the indicator scale 28b.

[0008]

In the conventional wire-type electric discharge machining apparatus of the immersion type as described above, only the initial liquid level in the steady state is displayed. However, it is not possible to determine whether the amount of liquid is appropriate when the processing liquid is contained. Therefore, in order to confirm the amount of reduction of the working fluid due to evaporation, scattering to the outside, etc., it is necessary to return to a steady state once and confirm by the liquid level indicator 26, and in the case of machining that requires a long time, Processing cannot be interrupted, and even such confirmation cannot be done.

In such a case, in order to prevent the filter pump 25 from sucking in air, it is often empirically predicted that the amount of reduction of the working fluid will be reduced, and the working fluid is replenished successively during the working. However, if the appropriate amount or more is replenished, the total amount of the liquid exceeds the capacity of the working liquid tank 20, and if the working liquid in the working tank 1 is discharged to the waste liquid tank 21 after the processing is completed, the working liquid tank 20 is discharged from the outside. Will overflow to. In order to prevent such a situation, it is conceivable to increase the capacity of the machining liquid tank 20 by adding an increase in the amount of liquid due to replenishment in advance, but this causes a problem of cost increase and installation space expansion.

The present invention has been made in order to solve the above problems, and provides a wire electric discharge machining apparatus capable of confirming a necessary machining liquid amount according to a liquid level in a machining tank even during machining. It is an object of the present invention to obtain a wire electric discharge machining apparatus including a machining fluid replenishing device that detects a shortage of the fluid volume and replenishes the fluid to an appropriate fluid volume.

[0011]

A wire electric discharge machine according to a first aspect of the present invention sets a machining tank in which a machining fluid for immersing a workpiece is stored, a liquid level in the machining tank, and a set fluid level. A liquid level setting device that discharges the machining liquid that has exceeded, a machining liquid supply device that supplies the machining liquid to the machining tank and stores the machining liquid discharged from the machining tank, and a machining liquid that corresponds to the set level of the machining tank. A liquid level indicator for determining an appropriate liquid level in the supply device.

A wire electric discharge machining apparatus according to a second aspect of the present invention includes a machining tank in which a machining fluid for immersing a work is stored,
A liquid level setter that sets the liquid level in the processing tank and discharges the processing liquid that exceeds the set liquid level, and supplies the processing liquid to the processing tank and stores the processing liquid discharged from the processing tank. A machining fluid supply device, a fluid level detection sensor that detects the fluid level of the machining fluid in the machining fluid supply device, and a solenoid valve installed in the machining fluid replenishment pipe that supplements the machining fluid in the machining fluid supply device. And the appropriate liquid level in the machining fluid supply device corresponding to the set fluid level value in the machining tank and the fluid level value in the machining fluid supply device detected by the fluid level detection sensor are compared and detected. Means for replenishing the machining fluid in the machining fluid supply device by opening the solenoid valve when the fluid level value in the machining fluid supply device is lower than the appropriate fluid level value corresponding to the set fluid level value And a control device having.

[0013]

In the wire electric discharge machining apparatus configured as described above, since the liquid level indicator indicates the proper amount of liquid corresponding to each liquid level in the machining tank, the operator does not have excess or insufficient machining liquid even during machining. Can be confirmed and the working fluid can be easily replenished. Further, in the second invention, the liquid level detection sensor detects the liquid level of the working liquid in the working liquid supply device, and outputs a signal corresponding to the liquid level to the control device. Then, the control device compares the detected liquid surface level value with the appropriate liquid surface level value in the machining liquid supply device corresponding to the set liquid surface level value of the processing tank, and the detected liquid surface level value is When the value is lower than the appropriate liquid level, the solenoid valve is opened to replenish the working fluid supply device with the reduced working fluid.

[0014]

【Example】

Example 1. FIG. 1 is a schematic view showing an embodiment of the first invention,
2 is an external perspective view of FIG. 1, and FIG. 3 is a perspective view showing a main part of the present invention. In the figure, 1 to 25 and 50 are the same parts as those of the conventional device shown in FIG. Reference numeral 30 denotes a liquid level indicator, which is a cylindrical holder 31 fixed to the upper surface of the processing liquid tank 20, a rectangular window portion 32 provided in the vertical direction on the front surface of the holder 31, and one side of the window portion 32 in the vertical direction. It is composed of a scale 33 displayed on the side, an indicator rod 34 which is vertically guided and supported by a holder 31, and a float 27 which is fixed to one end of the indicator rod 34 and moves up and down as the liquid level rises and falls. In addition, the indicator line 3 is provided on the upper portion of the indicator rod 34.
5 is displayed, and the pointing position of the pointing line 35 is the window 32.
It can be confirmed from outside via.

Next, the scale 33 will be described. The height position of the upper wire guide 6 is set according to the height of the work, and this position is displayed on the display of the control device 5 as a Z-axis set value. The liquid level of the processing tank 1 is set by the knob screw 11 corresponding to the Z-axis set value, and when the liquid level of the processing tank 1 is determined, the liquid level of the waste liquid tank 21 is determined correspondingly. Therefore, if the position indicated by the indicator line 35 of the liquid level indicator 26 at the proper liquid level of the wastewater tank 21 corresponding to the Z-axis set value is graduated in advance with the Z-axis set value, the Z-axis is set even during machining. By comparing the axis setting value and the numerical value indicated by the instruction line 35, it is possible to confirm whether the amount of machining fluid is excessive or insufficient. That is, the indicator line 3
If the numerical value indicated by 5 and the Z-axis set value displayed on the display of the control device 5 match, it indicates that the proper liquid amount set in the initial state is maintained, and the instruction line 35 indicates If the value to be set is larger than the Z-axis set value, it indicates that the amount is smaller than the proper liquid amount. Therefore, when the working fluid is decreasing, the operator only needs to replenish the working fluid until the instruction line 35 matches the Z-axis set value, and the work can be performed reliably while visually confirming.

Example 2. FIG. 4 is a schematic view showing an embodiment of the second invention. In the figure, 1 to 4, 6 to 25 and 50 are the same parts as those of the conventional device shown in FIG. Reference numeral 40 is a liquid level detection sensor attached to the bottom surface of the waste liquid tank 21, 41 is an electromagnetic valve that operates according to a command from the control device 5a, and is attached to a pipe for replenishing the processing liquid.

In the apparatus of the present embodiment configured as described above, the liquid level detection sensor 40 detects the pressure P of the waste liquid on the bottom of the waste tank 21, and outputs the pressure signal V to the controller 5a. .. Since the pressure P detected by the liquid level detection sensor 40 is proportional to the liquid level H of the waste liquid as shown in FIG. 5, the pressure signal V proportional to the pressure P is applied to the control device 5.
When output to a, the value of the pressure signal V becomes a value proportional to the liquid level H of the waste liquid tank 21. FIG. 6 shows the relationship between the pressure P detected by the liquid level detection sensor 40 and the pressure signal V output to the control device 5a. On the other hand, the control device 5a
Is set as the upper limit HU and the lower limit HL of the liquid level level of the waste liquid tank 21 corresponding to the Z-axis set value, and the liquid level detection sensor 40 sets the pressure PL corresponding to the lower limit value HL.
Is detected and the solenoid valve 41 is opened when the pressure signal VL is output, and the working fluid is replenished. Then, the liquid level of the waste liquid tank 21 rises, the liquid level detection sensor 40 detects the pressure PU corresponding to the upper limit value HU, and when the pressure signal VU is output, the solenoid valve 41 is closed.

FIG. 7 shows a timing chart in the above control. In FIG. 7A, the horizontal axis represents time and the vertical axis represents the liquid surface level of the waste liquid tank 21, and shows the fluctuation of the liquid surface level over time. In FIG. 7B, the horizontal axis represents time and the vertical axis represents the output value of the liquid level detection sensor 40, and shows the change in the output value of the liquid level detection sensor 40 over time. In FIG. 7C, the horizontal axis represents time and the vertical axis represents the open / closed state of the solenoid valve 41, and the open / closed state of the solenoid valve 41 at a certain time is shown. As shown in the figure, the liquid level of the wastewater tank 21 decreases with the elapse of the processing time, and when the liquid level detection sensor 40 detects the pressure PL corresponding to the lower limit value HL and outputs the pressure signal VL to the control device 5a. In response to this signal, the control device 5a sends a signal to open the solenoid valve 41, and the solenoid valve 41 opens. While the electromagnetic valve 41 is open, the working liquid is replenished and the liquid level in the waste liquid tank 21 rises, and the liquid level detection sensor 40 causes the pressure P corresponding to the upper limit value HU.
When U is detected and the pressure signal VU is output to the control device 5a, the control device 5a receives a signal from the control device 5a to send a signal to close the solenoid valve 41, and the solenoid valve 41 is closed. By repeating such a series of operations, the height of the liquid surface of the waste liquid tank 21 is always kept within a fixed range.

Although the wire electric discharge machining apparatus has been described in the above embodiment, if a liquid level detecting sensor is attached to the machining tank 1 and a signal of the liquid level of the machining tank 1 is transmitted to the control device 5a. It can also be applied to a die-sinking electric discharge machine.

[0020]

As described above, according to the present invention, the proper liquid amount in the machining liquid supply device corresponding to each liquid level of the machining tank can be confirmed by the liquid level indicator. Even in this case, the reduction amount of the working fluid can be confirmed, and an appropriate amount of the working fluid can be easily replenished.

Further, a liquid level detecting sensor installed in the machining liquid supply device detects the amount of decrease in the machining liquid,
Since the machining liquid is replenished by opening and closing the solenoid valve, the amount of the machining liquid can be kept constant during machining.

[Brief description of drawings]

FIG. 1 is a schematic view showing an embodiment of the first invention.

FIG. 2 is an external perspective view of FIG.

FIG. 3 is a diagram showing a liquid level indicator according to a first embodiment of the present invention.

FIG. 4 is a schematic view showing an embodiment of the second invention.

FIG. 5 is a diagram showing a relationship between a pressure P detected by a liquid surface level detection sensor and a liquid surface level H of a sewage tank according to a second aspect of the invention.

FIG. 6 is a diagram showing a relationship between a pressure P detected by a liquid surface level detection sensor and a pressure signal V output to a control device in the second invention.

FIG. 7 is a timing chart for explaining replenishment control of a working fluid in the second invention.

FIG. 8 is a schematic view showing a general wire electrical discharge machining apparatus of immersion specification.

9 is a schematic diagram showing a steady state of the wire electric discharge machine shown in FIG.

10 is a schematic diagram showing a state in which a machining fluid is filled in a machining tank of the wire electric discharge machining apparatus of FIG.

[Explanation of symbols]

 1 Processing tank 5a Control device 10 Processing tank liquid level setting device 30 Liquid level indicator 40 Liquid level detection sensor 41 Solenoid valve 50 Processing liquid supply device

Claims (2)

[Claims] 1. A machining tank in which a machining fluid for immersing a work is stored, and a liquid level setting device for setting a fluid level in the machining tank and discharging a machining fluid exceeding the set fluid level.
A machining liquid supply device that supplies the machining liquid to the machining tank and stores the machining liquid discharged from the machining tank, and an appropriate liquid level in the machining liquid supply device corresponding to the set level of the machining tank are determined. An electric discharge machine comprising: 2. A machining tank in which a machining fluid for immersing a workpiece is stored, and a liquid level setting device for setting a fluid level in the machining tank and discharging a machining fluid exceeding the set fluid level.
A machining liquid supply device that supplies the machining liquid to the machining tank and stores the machining liquid discharged from the machining tank, and a liquid level detection sensor that detects the liquid level of the machining liquid in the machining liquid supply device. A solenoid valve installed in a machining fluid replenishing pipe for replenishing the machining fluid in the machining fluid supply device, and an appropriate liquid level value in the machining fluid supply device corresponding to the set fluid level value in the machining tank, Comparing with the liquid level value in the machining liquid supply device detected by the liquid level detection sensor, the liquid level value in the machining liquid supply device corresponds to the set liquid level value An electric discharge machining apparatus comprising: a control device having means for opening the solenoid valve to replenish the machining fluid in the machining fluid supply device when the machining level is lower than the surface level value.