JPH04261712A - Wire cut electric discharging machining device - Google Patents

Abstract

PURPOSE:To decrease the installation area of a tank for recovering a work liquid, and further the installation area of a work liquid feeding device. CONSTITUTION:A water storage tank 2c stored with the work liquid overflowed by exceeding the capacity of a dipping tank 2a with the position of the bottom part being set at the higher position than that of the dipping tank 2a, is provided on a work tank 2, work liquid discharging parts 2d. 2e are respectively formed on the side wall of the bottom part vicinity. In each branch pipe 11a, 11b leading to the tank 5 of a work liquid feed device, check valves 13a, 13b checking the counterflow of the work liquid to the dipping tank 2a and water storage tank 2c respectively are provided. A drinage pump 12 having a speed set means sucking the work liquid via the respective check valves 13a, 13b from the dipping tank 2a or water storage tank 2c is set up at the downstream side than the confluence point inside the discharging route. The driving control of the drinage pump 12 is executed with the work liquid inside the dipping tank 2a and water storage tank 2c being detected by float switches 14a, 14b respectively.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wire-cut electric discharge machining apparatus that can reduce the installation area of a machining fluid supply device for supplying and discharging machining fluid to and from a machining tank.

0002

2. Description of the Related Art Generally, in a wire-cut electric discharge machining apparatus, a workpiece immersed in a machining fluid in a machining tank placed on an XY table is subjected to electric discharge machining using a wire electrode that is continuously fed out. The wire electrode after electrical discharge machining is
It is continuously pulled out from inside the processing tank and collected in a collection box. At this time, the wire electrode that is pulled out from inside the machining tank is pulled out from the inside of the machining tank to the outside with machining fluid attached thereto, so that the machining fluid in the machining tank decreases.

[0003] Therefore, in this type of wire-cut electrical discharge machining apparatus, machining fluid is constantly supplied into the machining tank, and means such as a toy are used to catch overflow machining fluid.

FIG. 2 is an overview diagram showing an example of a conventional wire-cut electric discharge machining apparatus, and FIG. 3 is an enlarged side view showing the main parts thereof. In the figure, 1 is the main body of the electric discharge machine to which a wire electrode (not shown) is attached and is fed out, 2 is installed on the table 3 (XY table is not shown) of the main body 1,
A machining tank (not shown) holds a workpiece immersed in machining fluid; 4 is a machining fluid supply device that supplies and discharges machining fluid to and from machining tank 2; 5 is located at a lower position than machining tank 2; is,
A tank 5a that stores the machining liquid discharged from the machining tank 2 through the discharge pipe 6 has an opening at its top.

As shown in FIG. 3, the machining tank 2 is provided with an immersion tank 2a in which the workpiece is accommodated, and an outside of one side of the immersion tank 2a, and is used to store processing liquid exceeding the capacity of the immersion tank 2a. and a toy 2b into which the water flows, and a discharge pipe 6 is connected to the lower end of the toy 2b.

A slidable discharge plate 7 is installed inside the dipping tank 2a to cover a lower opening (not shown) formed in the toy area, and when the discharge plate 7 is slid upward, the processing tank is removed. The machining fluid in the tank 2 passes through the discharge pipe 6, flows into the tank 5 from the upper opening 5a of the tank 5, and is collected.

Further, the machining liquid that exceeds the capacity of the immersion tank 2a passes through the toy 2b and directly flows into the tank 5 from the upper opening 5a of the tank 5, where it is collected.

[0008]

[Problems to be Solved by the Invention] However, as described above, the conventional wire is designed to collect the machining fluid discharged from the machining tank 2 into the tank 5 of the machining fluid supply device 4 by utilizing natural fall. In a cut electric discharge machining device, the tank 5 of the machining fluid supply device 4 is connected to the machining tank 2 on the side of the electric discharge machine main body.
Because it had to be placed at a lower position than the above, there were the following problems.

That is, since the machine is operated by a human, the height of the machine, particularly the height of the processing tank 2 into which workpieces are taken in and out, is set to a certain fixed height. For this reason, in the case where the machining fluid discharged from the machining tank 2 is recovered by gravity, the height of the machining fluid supply device 4, especially the height of the tank 5 from which the machining fluid is collected, is also determined. In other words, as long as the machining liquid capacity is constant, the installation area of the tank 5 and, by extension, the installation area of the machining liquid supply device 4 will not become smaller. Also, the rate of drainage cannot be controlled.

SUMMARY OF THE INVENTION In view of the above points, it is an object of the present invention to provide a wire-cut electrical discharge machining device that can reduce the installation area of a machining fluid supply device.

[0011]

[Means for Solving the Problems] A wire-cut electric discharge machining apparatus according to the present invention is formed to be separated from an immersion tank, and has a bottom position set at a higher position than that of the immersion tank, and a water storage tank in which the machining fluid that has flowed out in excess of the capacity of the dipping tank is stored; a first machining fluid discharge section provided on the side wall near the bottom of the dipping tank; and from the first machining fluid discharge section. and a second machining fluid discharge part provided on a side wall near the bottom of the water storage tank, which is in an upper position, and a vertical pipe having a plurality of branch pipes connected to each of the machining fluid discharge parts on one end side, A pipe that joins the machining fluid discharged from each machining fluid discharge section and leads it to the tank, and a pipe that is installed in a branch pipe that connects to the first machining fluid discharge section and prevents the machining fluid from flowing back into the immersion tank. a machining fluid discharge path consisting of the first check valve, a second check valve that is installed in a branch pipe connected to the second machining fluid discharge section and prevents the machining fluid from flowing back into the water storage tank, and the piping; A drainage pump is installed on the downstream side of the confluence point in the immersion tank and sucks up the machining liquid from the immersion tank or the water storage tank through the respective check valves, and a first float switch that detects the liquid; a second float switch installed in the water storage tank that detects the machining liquid in the water storage tank; and based on the judgment results and operation commands of each of the float switches. and drive control means for controlling the drive of the drainage pump.

0012

[Operation] In the present invention, different fluid pressures act on each check valve from the machining fluid in the vertical pipe of the pipe, and when the drainage pump is driven, the opening and closing control of each check valve is automatically controlled by this fluid pressure difference. Therefore, the discharge operation of the machining liquid in the water storage tank or the machining liquid in the immersion tank can be performed independently.

Furthermore, since the machining fluid is sucked up by the drainage pump and collected in the tank of the machining fluid supply device, the length of the tank is determined by the set height position of each machining fluid discharge part of the immersion tank and the water storage tank 2c. It can be installed to protrude upwards.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be explained below using illustrated embodiments.

FIG. 1 is a block diagram schematically showing a wire-cut electric discharge machining apparatus according to an embodiment of the present invention, in which parts corresponding to the conventional apparatus are given the same reference numerals. The wire-cut electric discharge machining apparatus of this embodiment has a machining tank 2 that fixes the workpiece in a state where it is immersed in the machining fluid, and an immersion tank 2a to which machining fluid is continuously supplied during machining, and an immersion tank 2a. and a water storage tank 2c, which is isolated and whose bottom position is set higher than that of the immersion tank 2a, and in which the machining fluid that has flowed out in excess of the capacity of the immersion tank 2a is stored. .

A first machining fluid discharge part 2d is bored in the lower part of the side wall of the immersion tank 2a on the side of the water storage tank.
One end of a first discharge pipe 11a extending in the horizontal direction is connected to the machining fluid discharge section 2d. Also, the water storage tank 2 is located at a higher position than the first machining fluid discharge part 2d of the immersion tank 2a.
A second machining fluid discharge part 2e is formed at the lower part of the side wall of c, and a first discharge pipe 1 is connected to the second machining fluid discharge part 2e.
One end of a second discharge pipe 11b, which has the same diameter as 1a and extends in parallel, is connected for communication. And these discharge pipes 11a, 11
The other end of b is a single third discharge pipe 11 extending vertically upward.
c. That is, the first and second
The discharge pipes 11a and 11b are formed as branch pipes, and the third discharge pipe 11c is formed as a machining liquid merging passage.

Furthermore, a drainage pump 12 is connected to the end of the third discharge pipe 11c, and the drainage pump 12 drains the immersion tank 2a.
Alternatively, the machining fluid can be sucked up from the water storage tank 2c, and the sucked machining fluid can be transferred to the drain pump 1.
A fourth discharge pipe 11d connected to 2 is passed through the tank of the machining fluid supply device, which is set to have a length that projects above the set height position of each machining fluid discharge port of the immersion tank 2a and the water storage tank 2c. 5 can be collected into the tank 5 through the upper opening 5a.

In the middle of each of the discharge pipes 11a and 11b, there is a pipe that prevents the machining fluid from flowing back from the drain pump 12 to the immersion tank 2a and the water storage tank 2c, and always fills the third discharge pipe 11c with the machining fluid. A first check valve 13a for generating a state in which the discharge pipe 11c is filled with priming water.
and a second check valve 13b are installed, respectively. Therefore, different hydraulic pressures from the machining fluid in the third discharge pipe 11c act on these check valves 13a and 13b, and the check valve 13a at the lower position is higher than the check valve 13b at the upper position. Since the connection position with the third discharge pipe 11c is low, the third discharge pipe 11
The fluid pressure received from the machining fluid in c is high. This fluid pressure difference plays an important role in the discharge operation of the machining fluid in the water storage tank, which will be described later.

Each of the check valves 13a and 13b is provided with a spring that urges the valve body toward the processing tank 2, and among these, the spring on the immersion tank 2a side is When the machining fluid is in a full state, the spring constant is such that the valve body of the check valve 13a can be closed at the last possible moment, and the spring on the water storage tank 2c side is set so that the machining fluid reaches a predetermined water level in the water storage tank 2c. When the water level is slightly lower than this water level, the spring constants are set so that the valve body of the check valve 13b can be closed just at the last possible moment. These spring constants are set ignoring the hydraulic pressure received from the machining fluid in the third discharge pipe 11c, and the predetermined water level in the water storage tank 2c is defined as the discharge of the machining fluid in the water storage tank 2c. The timing is the water level.

A first float switch 14a is provided inside the immersion tank 2a to detect the machining fluid in the immersion tank 2a, and is also provided inside the water storage tank 2c to detect the machining fluid in the water storage tank 2c. A second float switch 14b is installed, and detection signals from each float switch 14a, 14b are output to the numerical control device 15, respectively.

The numerical control device 15 includes an amplifier 16a that amplifies the input signal from each float switch 14a, 14b.
, 16b, an in-immersion tank machining fluid presence determining means 17a for determining the presence or absence of machining fluid in the immersion tank 2a from the detection result of the float switch 14a sent via the amplification device 16a, and an amplification device 16b. Processing fluid presence/absence determination means 17b in the water storage tank determines the presence or absence of machining fluid in the water storage tank 2c based on the detection result of the float switch 14b sent through the system, and the determination results of these machining fluid presence/absence determination means 17a, 17b. and a stop/discharge command signal output means 19 for controlling the stop/discharge of the drainage pump 12 based on the program 18 and an external input means such as a knob.
It has a drive control circuit 20 that sets the speed of the drainage pump 12 that is drive-controlled by the drain pump 12 .

When the processing fluid presence determination means 17b in the water storage tank determines that processing fluid is present in the water storage tank 2c from the detection result of the float switch 14b, the stop/discharge command signal output means 19
It has a delay circuit (not shown) that delays a predetermined period of time and outputs a signal indicating the presence of machining fluid. Thereby, the number of operations of the drain pump 12 can be reduced and its lifespan can be extended.

The stop/discharge command signal output means 19 outputs a discharge command signal to the drain pump 12 to operate the drain pump 12 while the processing fluid presence/absence determining means 17b in the water storage tank determines that the processing fluid is present. When the discharge command is issued by the program 18, a discharge command signal is output to the drain pump 12 while the machining fluid presence determining means 17a determines that the machining fluid is present in the immersion tank. Further, when the signal output from each machining fluid presence/absence determining means 17a, 17b disappears, a stop command signal is immediately output to the drain pump 12 to stop the drain pump 12, and the third drain The state in which the pipe 11c is always filled with machining fluid is maintained.

Next, the operation of the wire-cut electric discharge machining apparatus of this embodiment having the above-described configuration will be explained. In addition,
Since the operation of electric discharge machining itself is well known, only the discharge control of the machining fluid will be explained here. It is also assumed that the speed of the drain pump 12 is set in advance by a knob.

First, a workpiece is fixed in the immersion tank 2a, and a wire electrode is passed through the machining start hole.
A is filled with machining fluid. Then, when the wire electrode is fed out and electrical discharge machining is started, machining fluid is continuously supplied into the immersion tank 2a. At this time, float switch 1
4a detects the presence of machining fluid in the immersion tank 2a, and outputs the detection signal to the presence/absence determination means 17a of machining fluid in the immersion tank via the amplifier 16a.

The processing fluid presence/absence determination means 17a in the immersion tank includes the following steps:
Based on the detection result of the float switch 14a, it is determined that there is machining fluid in the immersion tank 2a, and a machining fluid presence signal is output to the stop/discharge command signal output means 19 to notify that there is machining fluid in the immersion tank 2a. .

When the stop/discharge command signal output means 19 receives the processing fluid presence signal from the processing fluid presence determination means 17a in the immersion tank, the program 18 checks whether a discharge command has been output and outputs the discharge command. If not, the drain pump 12 is placed in a stopped state.

Next, when the machining fluid overflows from the immersion tank 2a and flows into the water storage tank 2c, the float switch 14b detects this and transmits the detection signal to the machining fluid in the water storage tank via the amplifier 16b. It is output to the presence/absence determining means 17b.

In the water storage tank processing fluid presence/absence determination means 17b,
It is determined that machining fluid is present in the water storage tank 2c from the detection result of the float switch 14b, and after a predetermined delay, the stop/discharge command signal output means 19 is notified that machining fluid is present in the water storage tank 2c. Output a signal.

The stop/discharge command signal output means 19 outputs a discharge command signal to the drive control circuit 20 to start the drain pump 12 when a machining fluid presence signal is input from the water storage tank machining fluid presence determination means 17b. drive.

At this time, each check valve 13a, 13b is in the state described below.

That is, the check valve 13a located at the lower position uses its spring force to maintain the back pressure that the valve element receives from the processing liquid in the immersion tank, and furthermore, the check valve 13a maintains the back pressure that the valve body receives from the processing liquid in the immersion tank, and furthermore, the back pressure applied to the valve body from the processing liquid in the third discharge pipe is added to this holding force. It is in a state where a certain amount of hydraulic pressure is applied. In addition, the check valve 13b located at the upper position maintains the back pressure that the valve body receives from the processing liquid in the water storage tank with its spring force, and further adds to this holding force the back pressure that is applied to the valve body from the processing liquid in the third discharge pipe. The hydraulic pressure is applied.

Therefore, when the drain pump 12 is driven, the suction force of the drain pump 12 is applied to the check valve 13b located at the upper position.
On the other hand, since the pressure of the machining fluid in the third discharge pipe is lower than that of the check valve 13a located at the lower position, it acts more strongly. As a result, the check valve 13b opens before the check valve 13a, and the water storage tank 2c
The machining fluid inside is introduced into the third discharge pipe 11c.

Third discharge pipe 11 for processing fluid in water storage tank 2c
When the introduction into the tank 2c starts, the suction force of the drain pump 12 also acts on the machining fluid in the water storage tank 2c, and the back pressure applied to the valve body of the check valve 13b further increases, causing the valve body to become larger. The check valve 13b is opened to increase the flow rate passing through the check valve 13b. As a result, the flow rate required by the drain pump 12, that is, the flow rate to be introduced into the third drain pipe 11c determined by the suction force of the drain pump 12, can be ensured entirely by the flow rate passing through the check valve 13b. , while the check valve 13b is open,
The check valve 13a in the lower position is placed in a closed state. At this time, the check valve 13a in the lower position receives the hydraulic pressure corresponding to the depth from the machining liquid in the third discharge pipe 11c and the spring pressure of the check valve 13a itself, and the valve body receives the spring pressure of the check valve 13a itself, and is in a closed state.

When all of the machining fluid in the water storage tank 2c is introduced into the third discharge pipe 11c, there is no signal input from the float switch 14b to the water storage tank machining fluid presence/absence determination means 17b. The in-tank machining fluid presence determination means 17b determines that there is no machining fluid in the water storage tank 2c, and sends a machining fluid no signal to the stop/discharge command signal output means 19 to inform that there is no machining fluid in the water storage tank 2c. Output.

The stop/discharge command signal output means 19 outputs a stop command signal to the drive control circuit 20 to start the drain pump 12 when there is no machining fluid signal input from the water storage tank machining fluid presence determination means 17b. Stop immediately.

When the drain pump 12 stops and its suction force disappears, the valve body of the check valve 13b moves to the third drain pipe 11c.
It receives hydraulic pressure corresponding to the depth from the machining fluid inside and the spring pressure of the check valve 13b itself, and is biased toward the water storage tank 2c and closed. In this state, only air exists in the water storage tank 2c, and the pressure that acts as back pressure is much lower than that of liquid. collapses significantly, and the force with which the valve body is biased in the closing direction by the spring becomes relatively large. As a result, the force that causes the check valve 13b to close, including the hydraulic pressure corresponding to the depth received from the machining fluid in the third discharge pipe, becomes larger than that of the check valve 13a located at the lower position.

Next, when the force for closing the check valve 13b is greater than that of the check valve 13a in the lower position as described above, that is, there is no machining liquid in the water storage tank 2c. When the program 18 outputs a discharge command when there is no liquid and the immersion tank 2a is filled with machining fluid, the stop/discharge command signal output means 19 sends a discharge command signal to the drive control circuit 20. output and drain pump 12
drive.

When the drain pump 12 is driven, the suction force of the drain pump 12 is applied to the check valve 13b located at the upper position.
Since the pressure of the machining fluid in the third discharge pipe is lower than that of the check valve 13a located at the lower position, it acts more strongly. However, at this point, each check valve 13a,
Since the difference in the force for closing the valve body between valves 13b is larger, check valve 13a opens earlier than check valve 13b, and the machining liquid in immersion tank 2a is drained to third discharge pipe 11c.
be introduced within.

[0040] Third discharge pipe 11 for machining fluid in the immersion tank 2a
When the introduction into the tank c starts, the suction force of the drain pump 12 also acts on the machining fluid in the immersion tank 2a, and the back pressure that the valve body of the check valve 13a receives from the machining fluid in the immersion tank further increases. , the valve body is opened wide to increase the flow rate passing through the check valve 13a. As a result, the flow rate required by the drain pump 12 can be secured entirely by the flow rate passing through the check valve 13a, so while the check valve 13a is open, the check valve 13b in the upper position is closed. placed in a state. At this time, the check valve 13b in the upper position has a valve body that is connected to the third discharge pipe 11c.
The check valve 13b receives hydraulic pressure corresponding to the depth from the machining fluid inside and the spring pressure of the check valve 13b itself, and is biased toward the water storage tank 2c and is in a closed state.

When all of the machining liquid in the immersion tank 2a is introduced into the third discharge pipe 11c, the signal input from the float switch 14a to the in-immersion tank machining liquid presence/absence determination means 17a is eliminated, so that The machining fluid presence determination means 17a determines that there is no machining fluid in the immersion tank 2a, and outputs a machining fluid no signal to the stop/discharge command signal output means 19 to inform that there is no machining fluid in the immersion tank 2a. .

The stop/discharge command signal output means 19 outputs a stop command signal to the drive control circuit 20 to immediately start the drain pump 12 when there is no processing fluid signal input from the processing fluid presence determination means 17a in the immersion tank. make it stop.

When the drain pump 12 stops and its suction force disappears, the valve body of the check valve 13a moves to the third drain pipe 11c.
The check valve 13a receives the hydraulic pressure corresponding to the depth from the machining fluid inside and the spring pressure of the check valve 13a itself, and is biased toward the immersion tank 2a and closed. In this state, there is only air inside the immersion tank 2a, which has a much lower back pressure than the liquid.
If we focus only on the spring of the check valve 13a, the state of balance with the back pressure will be greatly disrupted, and the force with which the valve element is biased in the closing direction by the spring will become relatively large. As a result, the check valve 13 receives the hydraulic pressure corresponding to the depth from the machining fluid in the third discharge pipe.
The force for closing a is larger than that of the check valve 13b located at the upper position as initially set.

As described above, the wire-cut electrical discharge machining apparatus of this embodiment uses the difference in fluid pressure applied to each check valve 13a, 13b to discharge the machining fluid in the water storage tank or the machining fluid in the immersion tank. can be performed independently in the same manner as before.

Furthermore, since the discharged machining fluid is sucked up by the drain pump 12 and collected in the tank 5 of the machining fluid supply device, the length of the tank 5 can be adjusted according to each machining process in the dipping tank 2a and the water storage tank 2c. It can be installed to protrude above the set height position of the liquid discharge part, and the installation area of the tank 5,
In turn, the installation area of the machining fluid supply device can be reduced.

Furthermore, since the speed of the drain pump 12 can be set using external input means such as a knob, it is possible to control the drain speed.

Note that in the embodiment described above, each check valve 13a
, 13b are automatically closed by the hydraulic pressure received from the machining fluid in the third discharge pipe 11c and the spring pressure of the check valve itself. Alternatively, the numerical control device may be provided with a valve opening/closing control means for controlling the opening/closing operations of these solenoid valves in synchronization with the driving/stopping timing of the drainage pump. It has the following effects.

[0048]

As described above, according to the present invention, the tank of the machining fluid supply device can be set to a length that protrudes above the set height position of the machining fluid discharge portion of the machining tank.
This has the effect of reducing the installation area of the tank and, by extension, the installation area of the machining fluid supply device.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram schematically showing a wire-cut electric discharge machining apparatus according to an embodiment of the present invention.

FIG. 2 is an external view schematically showing an example of a conventional wire-cut electric discharge machining apparatus.

FIG. 3 is a side view showing an enlarged main part of a conventional wire-cut electrical discharge machining apparatus.

[Explanation of symbols]

2 Processing tank 2a Immersion tank 2c Water storage tank 2d First machining fluid discharge part 2e Second machining fluid discharge part 4 Processing fluid supply device 5 Tank 11a First discharge pipe (branch pipe) 11b Second discharge pipe (branch pipe) 11c Third discharge pipe (vertical pipe) 11d Fourth discharge pipe 12 Drain pump 13a First check valve 13b Second check valve 14a First float switch 14b Second float switch

Claims (1)

[Claims] Claim 1: A machining tank of an electric discharge machine having an immersion tank in which a workpiece is fixed while being immersed in a machining fluid and to which machining fluid is continuously supplied during machining, and a machining machine that is discharged from the machining tank. It has a tank for recovering the liquid and a machining liquid supply device that supplies and discharges the machining liquid between the machining tank and the workpiece immersed in the machining liquid using a wire electrode that is continuously fed out. In a wire-cut electrical discharge machining device for electrical discharge machining, the device is formed to be separated from the immersion tank, and the bottom position is set higher than that of the immersion tank, and the flow exceeds the capacity of the immersion tank. a water storage tank in which the machining fluid is stored, and a first tank provided on the side wall near the bottom of the immersion tank.
and a second machining fluid discharge part provided on the side wall near the bottom of the water storage tank, which is located above the first machining fluid discharge part.
It has a machining fluid discharge part and a vertical pipe with a plurality of branch pipes connected to each of the machining fluid discharge parts on one end side, and the machining fluid discharged from each machining fluid discharge part is merged into the tank. a first check valve that is installed in a branch pipe that connects to the first machining fluid discharge section and prevents backflow of the machining fluid to the immersion tank; and a branch that connects to the second machining fluid discharge section. A second check valve is installed in the pipe and prevents the machining fluid from flowing back into the water storage tank, and a second check valve is installed downstream of the confluence point in the machining fluid discharge path consisting of the piping and prevents the machining fluid from flowing back into the water storage tank. a drain pump that sucks up the machining fluid from the water tank through each check valve; a first float switch installed in the immersion tank to detect the machining fluid in the immersion tank; and a first float switch installed in the water storage tank. and a second float switch for detecting the machining fluid in the water storage tank, and a drive control means for controlling the drive of the drainage pump based on the determination results and operation commands of each of the float switches. Wire cut electrical discharge machining equipment featuring: