JPH05261620A - Electro-discharge machine - Google Patents

Abstract

PURPOSE:To provide an electro-discharge machine that recognizes a dielectric fluid level position in a work tank, positioning a dielectric fluid level without resting on the level setting by an operator, and is able to improve the extent of reliability on operational automation and fire prevention. CONSTITUTION:This machine is provided with a flow detector 8 detecting a flow rate of dielectric fluid, a work tank position detector 12 detecting a height position of a work tank 1, a keyboard 16 setting height of a workpiece, a lifting motor 11 making the work tank 1 go up and down, and an arithmetic processing part 21 controlling every part concerned. This arithmetic processing part 21 judges a height position of the work tank 1 as that of a dielectric fluid level when there is a dielectric fluid outflow from a dielectric fluid outlet 6, and it controls the lifting motor 11 so as to shift the work tank to a position, where the dielectric fluid level is situated, in the more upper part than height of the workpiece 2 set up by the keyboard 16 at the specified interval.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric discharge machine for fixing a workpiece to be machined in a machining fluid stored in a machining tank and performing electric discharge machining.

[0002]

2. Description of the Related Art As is well known, since an electric discharge machine performs electric discharge in a combustible mineral oil to perform machining, it always involves a risk of fire. In order to cut off oxygen, which is one of the problems, it is essential in electric discharge machining to immerse a workpiece in a machining fluid for machining. Generally, it is said that it is desirable that the working liquid level is 50 mm or more above the workpiece (hereinafter, the distance between the working liquid surface and the workpiece is a safety distance). On the other hand, if the machining liquid surface is set extremely above the workpiece, it is difficult to observe the electrical discharge machining state during machining, which is not a good idea. Therefore, in the electric discharge machining, it is necessary to position the machining liquid surface at an optimum position according to the height of the workpiece.

FIG. 6 is a sectional view showing a conventional electric discharge machine. The electric discharge machine has a vertically movable machining tank 1 for storing a machining fluid 7 such as flammable mineral oil, and a hole 1a is opened at the bottom of the machining tank 1. The machining tank 1 is shown in the drawing. It is designed so that it can be raised and lowered by a drive means that does not. Further, in the hole 1a of the processing tank 1, a table 3 for fixing the workpiece 2 is provided.
Is inserted, and the hole 1a of the processing tank 1 and the table 3 are sealed by packing 4, and the table 3 is
A supply pipe 3a is provided to guide the processing liquid 7 supplied from a pump (not shown) into the processing tank 1. An electrode 5 for discharging is opposed above the processing tank 1. Further, the processing tank 1 is provided with a processing liquid outlet 6 for discharging the overflowing processing liquid 7, and the processing liquid outlet 6 has
A flow rate detector 8 that detects the amount of the machining fluid 7 that overflows is provided.

Next, the operation will be described. The machining fluid supplied through the supply pipe 3a fills the machining tank 1, and the overflowing machining fluid 7 flows out from the machining fluid outlet 6 provided in the machining tank 1. As a result, the surface of the processing liquid for the processing tank becomes constant. Then, the workpiece 2 is fixed to the table 3 fixed to the base of the electric discharge machine, and the machining liquid outlet 6 is separated from the workpiece 2 by a safety distance according to the height of the workpiece 2. The machining tank 1 is raised so as to be positioned, the machining liquid surface with respect to the workpiece 2 is positioned, and electric discharge machining is performed.

[0005]

DISCLOSURE OF THE INVENTION A conventional electric discharge machine is
It is configured as described above, the work must be performed visually by the operator, and the reliability is poor in terms of whether a safe distance is maintained between the workpiece and the machining liquid surface,
Further, when the operator forgets this setting, there is a problem that the machining cannot be performed normally, and the machining liquid 7 may be ignited during the machining.

The present invention has been made to solve the above problems, and the electric discharge machine recognizes the position of the machining liquid surface in the machining tank, and the machining liquid is set without depending on the operator's liquid level setting. It is an object of the present invention to provide an electric discharge machine capable of positioning a surface and improving the automation of work and the reliability of fire prevention.

[0007]

An electric discharge machine according to the present invention detects a machining tank that stores a machining fluid and can be moved up and down, and a flow rate of the machining fluid flowing out from a machining fluid outlet provided in the machining tank. Flow detector, a position detector that detects the height position of the machining tank, and the height position of the machining tank is determined as the height position of the machining liquid when there is a machining fluid outflow from the machining fluid outlet. It is characterized in that it is provided with the judging means of No. 1.

Further, the electric discharge machine according to the present invention comprises a drive device for raising and lowering the machining tank, a data input device for setting the height of the workpiece, and a height of the workpiece set by the data input device. And a control means for controlling the driving means to move the machining tank so that the machining liquid surface is positioned at a predetermined distance above the machining tank.

Further, the electric discharge machine according to the present invention has a discharge control means for controlling the discharge from the electrodes, a data input device for setting the height of the electrodes, and a position for detecting the position of the head to which the electrodes are attached. The electrode height set by the data input device is subtracted from the position of the detector and the head detected by the position detector to obtain the electrode lower end position, and the electrode lower end position is located below the machining tank height with a predetermined interval. And an arithmetic processing means for controlling the discharge control means so as to stop the discharge from the electrode.

In the electric discharge machine according to the present invention, when the machining tank is moved by the driving means to immerse the workpiece in the machining fluid, the electric discharge machine changes from the machining fluid outflow amount flowing out from the machining fluid outlet. The second to judge that the processed product is immersed in the processing liquid
It is characterized in that it is provided with the judging means.

[0011]

Based on the above configuration, the electric discharge machine according to the present invention detects the flow rate of the machining fluid flowing out from the machining fluid outlet by the flow rate detector and the height position of the machining tank by the position detector to perform machining. When the machining liquid flows out from the liquid outlet, the height position of the machining tank is judged as the height position of the machining liquid surface by the first judging means.

Further, in the electric discharge machine according to the present invention, the machining tank is moved up and down to a predetermined position by the driving device, the height of the workpiece is set by the data input device, and the workpiece set by the data input device is set. The driving means is controlled by the control means so as to move the machining tank to a position where the machining liquid surface is located above the height at a predetermined interval, and the machining liquid surface is positioned at a predetermined interval with respect to the workpiece. To do.

Further, in the electric discharge machine according to the present invention, the height of the electrode is set by the data input device, the position of the head to which the electrode is attached is detected by the position detector, and the position of the head detected by the position detector is detected. Then, the electrode height set by the data input device is subtracted to obtain the electrode lower end position, and when the electrode lower end position is not below the machining tank height with a predetermined interval, the discharge from the electrode is stopped. The control means is controlled by the arithmetic processing means.

In the electric discharge machine according to the present invention, when the machining tank is moved by the driving means and the workpiece is immersed in the machining fluid, the electric discharge machine changes from the variation of the machining fluid outflow from the machining fluid outlet. It is judged by the second judging means that the processed product is immersed in the processing liquid.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 2 is a cross-sectional view of essential parts showing an electric discharge machine according to an embodiment of the present invention. This electric discharge machine has a vertically movable machining tank 1 for storing a machining fluid 7 such as flammable mineral oil, and a hole 1a is opened at the bottom of the machining tank 1. And the ball nut 9 is fixed to the processing tank 1,
A ball screw 10 is screwed onto the ball nut 9.
Further, the ball screw 10 is connected to a lifting motor 11 as a driving means, and the ball motor 10 is rotated by the lifting motor 11 so that the processing tank 1 is lifted together with the ball nut 9. Further, the lifting motor 11 is provided with a processing tank position detector 12 that detects the height position of the processing tank 1 by detecting the rotational position of the lifting motor 11. A table 3 for fixing the workpiece 2 is inserted into the hole 1a of the processing tank 1, and the hole 1a of the processing tank 1 and the table 3 are sealed by a packing 4, and the table 3 has Supply pipe 3 that guides the processing liquid 7 supplied from a pump (not shown) into the processing tank 1.
a is provided, and the supply pipe 3a is provided with an electromagnetic valve 13 for turning on / off the inflow of the processing liquid 7. Also,
A head 14 that can be moved up and down is provided above the processing tank 1, an electrode 5 that discharges is provided in the head 14, and a position detector 1 that detects the position of the head 14 is provided.
5 are provided. Further, the machining tank 1 is provided with a machining fluid outlet 6 for discharging the overflowing machining fluid 7, and the machining fluid outlet 6 has a flow rate detection for detecting the amount of the machining fluid 7 overflowing. A container 8 is provided.

On the other hand, the electric discharge machine, as shown in FIG.
The keyboard 16 has a keyboard 16 for setting the height of the workpiece, and the keyboard 16 stores input information in the safety distance storage unit 17 or the electrode information storage unit 18 or displays / displays it on the CRT 19. The control unit 20 is connected. The safety distance storage unit 17 and the electrode information storage unit 18 are connected to a first determination unit, a control unit, an arithmetic processing unit, and an arithmetic processing unit 21 as a second determination unit. 21 is a processing tank position detector 1
2, a processing tank position input section 22 for inputting a signal from the processing tank 2, a processing tank drive control section 23 for controlling the lifting motor 11, a flow rate input section 24 for inputting a signal from the flow rate detector 8, and a head 14.
Head position input section 25 for inputting a signal from the position detector 15 for detecting the position of the solenoid valve, solenoid valve control section 26 for controlling the solenoid valve 13, discharge control section 2 for controlling discharge by the electrode 5.
7, and a workpiece height storage unit 29 that stores the workpiece height information d3 from the NC information input unit 28 that reads the NC program 100 is connected.

Next, the operation of this embodiment will be described.
The NC program 100 is read by the NC information input unit 28, and the workpiece height information d3 is stored in the workpiece height storage unit 29.
Stored in. On the other hand, the distance from the machining liquid surface to the work piece 2, that is, the safety distance information d1 is stored in the safety distance storage unit 17 from the keyboard 16 via the input / display control unit 20. Then, when the operation is started, the arithmetic processing unit 21
Then, the safety distance information d1 and the workpiece height information d3 are added, and the added value and the processing tank position information d4 read from the processing tank position detector 12 via the processing tank position input unit 22.
The machining tank drive control unit 23 drives the elevation drive motor 11 so that the machining tank 1 and the machining tank 1 are moved.

Then, the arithmetic processing unit 21 reads the machining fluid flow rate information d5 from the flow rate detector 8 via the flow rate input 24 and confirms that the machining fluid 7 is flowing out from the machining fluid outlet 6, It is guaranteed that the workpiece 2 is immersed in the machining liquid 7, and the automatic setting process of the machining liquid surface ends. On the other hand, the electrode length information d2 is stored in the electrode information storage unit 18 via the input / display control unit 20 like the safety distance information d1.
Stored in. The arithmetic processing unit 21 includes the head position input unit 2
The electrode length information d2 is subtracted from the head position information d6 read via 5 to obtain the electrode lower end position. When this electrode lower end position does not exist below the machining tank position information d4, that is, at a predetermined distance from the machining liquid surface, the discharge control unit 27 is instructed to prohibit discharge. As a result, the lower end position of the electrode and the machining liquid surface position are compared and monitored by the absolute position amount, and at least the lower end of the electrode is immersed in the machining liquid surface even if there is an error in NC data or an error in setting the origin position of NC coordinates. If it is not, the discharge will not occur,
The risk of fire is reduced.

Next, a process in which the electric discharge machine automatically recognizes the height of the workpiece will be described with reference to the flowchart of FIG. The arithmetic processing unit 21 first moves the processing tank 1 to the upper limit position by the elevation drive motor 11 via the processing tank drive control unit 23 (step 1), and opens the electromagnetic valve 13 by the electromagnetic valve control unit 26 to supply the supply pipe 3a. The machining liquid 7 flows in from the inlet of (step 2). Then, based on the machining fluid flow rate information d5 from the flow rate input unit 24, it is judged whether or not the machining fluid is flowing out from the machining fluid outlet 6 (step 3), and when it is judged that the machining fluid is flowing out, that is, in the machining tank 1. After confirming that the processing liquid 7 has been filled, the processing tank 1 is moved to the lower limit position by the elevation drive motor 11 via the processing drive control unit 23 (step 4). This means that when the workpiece 2 has a recess 2a on the upper surface as shown in FIG. 4, for example, when the machining liquid surface accompanying the rise of the machining tank 1 reaches the edge 2b of the recess, the machining liquid 7 Flow into the concave portion 2a, and the machining liquid level in the machining tank 1 is temporarily lowered to prevent the machining liquid from flowing out, so that the machining liquid 2 reaches the upper end 2c of the workpiece 2 before the machining liquid surface reaches the upper end 2c. May be determined to have been immersed in the machining liquid, and therefore the machining tank 1 is once moved to the upper limit and the machining tank 7 is filled with the machining liquid 7 before the recognition process is performed. This is because the machining liquid 7 is stored in advance in the recess 2a to prevent the machining liquid from flowing into the recess 2a in the process of recognizing the height of the workpiece, thereby avoiding a determination error. At this time, again, it is confirmed from the machining fluid inflow amount information d5 that the machining fluid is flowing out from the machining fluid outlet 5 (step 5), and after confirming that the machining tank 7 is filled with the machining fluid 7. The electromagnetic valve controller 27 closes the electromagnetic valve 13 to stop the supply of the machining liquid (step 6) (see FIG. 5A).

Then, the arithmetic processing section 21 starts the raising of the processing tank 1 again by the elevation drive motor 11 via the processing tank drive control section 23 (step 7). As a result, the table 3 and the workpiece 2 relatively enter the machining tank 1 (see FIG. 5 (b)), and the outflow of the machining liquid is detected by the flow rate detector 8. When the workpiece 2 is completely immersed in the machining fluid 7, the machining fluid 7 does not flow out (see FIG. 5).
(See (c)). The flow rate is 0 according to the machining fluid inflow information d5.
(Step 8), the processing tank position information d4 is stored in the workpiece height storage section 29 as the workpiece height information d3 (step 9). Further, the arithmetic processing unit 21 is provided in the processing tank 1
The machining tank drive controller 23 drives the lifting drive motor 11 so that the height position of the machining tank coincides with the position of the stored workpiece height information d3 and the safety distance information d1.
(Step 10) (see FIG. 5D), the solenoid valve 13 is opened, and the supply of the machining fluid 7 is restarted (Step 1).
1).

[0021]

As described above, according to the electric discharge machine of the present invention, the flow rate of the machining fluid flowing out from the machining fluid outlet is detected by the flow rate detector to detect the height position of the machining tank. The height of the machining tank is determined as the height position of the machining liquid surface by the first determining means when the machining liquid is discharged from the machining liquid outlet through the machining device. It is not necessary to manage the liquid surface, the liquid surface position can be recognized with high accuracy, and workability and fire protection reliability can be improved.

Further, according to the electric discharge machine of the present invention, the height of the work piece is set by the data input device, and the height of the work piece is set at a predetermined interval above the height of the work piece set by the data input device. The drive means is controlled by the control means so as to move the machining tank to the position where the liquid surface is located, and the machining liquid surface is positioned at a predetermined interval with respect to the workpiece. On the other hand, the machining liquid surface is automatically positioned at a predetermined interval to eliminate the need for the operator to manage the machining liquid surface, and the setup time at the time of machining can be reduced.

Further, according to the electric discharge machine of the present invention, the height of the electrode is set by the data input device, the position of the head to which the electrode is attached is detected by the position detector, and the head is detected by the position detector. The electrode height set by the data input device is subtracted from the position to determine the electrode bottom end position, and the discharge from the electrode is stopped when the electrode bottom end position is not below the machining tank height with a predetermined interval. Since the electric discharge control means is configured to be controlled by the arithmetic processing means, the machining can be stopped in response to a command such that the tip position of the electrode is to perform electric discharge machining above the machining liquid level, which improves safety. Can be planned.

According to the electric discharge machine of the present invention, when the machining tank is moved by the driving means to immerse the workpiece in the machining fluid, the discharge amount of the machining fluid flowing out from the machining fluid outlet is changed so that the machining fluid is discharged. Since the second judging means judges that the workpiece is immersed in the machining liquid, the machining is stopped in response to a command to perform electric discharge machining when the tip position of the electrode is above the machining liquid surface. Therefore, it is possible to improve safety.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an electric discharge machine according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of essential parts showing an electric discharge machine according to this embodiment.

FIG. 3 is a flowchart showing the operation of this embodiment.

FIG. 4 is a perspective view showing an example of a workpiece.

FIG. 5 is a diagram showing an operation of this embodiment.

FIG. 6 is a cross-sectional view of essential parts showing a conventional electric discharge machine.

[Explanation of symbols]

 1 Processing Tank 2 Workpiece 3a Supply Pipe 5 Electrode 6 Processing Fluid Outlet 7 Processing Fluid 8 Flow Rate Detector 9 Ball Nut 10 Ball Screw 11 Lifting Motor 12 Processing Tank Position Detector 13 Solenoid Valve 14 Head 15 Position Detector 16 Keyboard 21 Arithmetic processing unit

Claims (4)

[Claims] 1. An electric discharge machine for fixing a workpiece in a state of being immersed in a machining fluid and performing electric discharge machining, a machining tank which stores the machining fluid and is capable of moving up and down, and a machining fluid outlet provided in the machining tank. The flow rate detector that detects the flow rate of the machining fluid flowing out from the position detector, the position detector that detects the height position of the machining tank, and the machining tank height position when the machining fluid flows out from the machining fluid outlet. An electric discharge machine comprising: a first determining means for determining the height position of the surface. 2. A drive device for raising and lowering the processing tank, a data input device for setting the height of a workpiece, and a position at a predetermined distance above the height of the workpiece set by the data input device. So that the machining liquid surface is located at
The electric discharge machine according to claim 1, further comprising: a control unit that controls the driving unit to move the machining tank. 3. A discharge control means for controlling discharge from an electrode, a data input device for setting a height of the electrode, a position detector for detecting a position of a head to which the electrode is attached, and a position detector for detecting the position. The electrode height set by the data input device is subtracted from the position of the head to obtain the electrode lower end position, and the electrode discharge is generated when the electrode lower end position is not below the machining tank height with a predetermined interval. The electric discharge machine according to claim 1 or 2, further comprising: arithmetic processing means for controlling the electric discharge control means so as to stop. 4. The work piece is immersed in the machining liquid due to a change in the amount of the machining liquid flowing out from the machining liquid outlet when the work tank is moved by the driving means to immerse the work piece in the machining liquid. 4. An electric discharge machine according to claim 1, further comprising a second judging means for judging.