JPH05208322A - Soak type electric discharge machining device - Google Patents

Abstract

PURPOSE:To always equally maintain sludge concentration by providing a supply quantity control means for controlling the supply quantity of machining liquid to be supplied to a machining tank through a machining liquid supply means based on the computed result of a machining quantity computing means. CONSTITUTION:Machining liquid 11 in a machining liquid tank 13 is supplied to a machining tank 12 by a machining liquid supply means 14, and a work piece 2 is soaked in the machining liquid 11 stored in the machining tank 12 so as to be machined by electric discharge. In this case, the machining quantity of the work piece 2 is computed by a machining quantity computing means 50. Next, the supply quantity of machining liquid 11 to be supplied to the machining tank 12 by the machining liquid supply means 14 is controlled by a supply quantity control means 50, based on the computed result of the machining quantity computing means 50. Sludge concentration in the machining tank 12 is always maintained constant, and cleanness is kept without soiling.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an immersion type electric discharge machine, and more particularly to an immersion type electric discharge machine for controlling the sludge concentration of a machining fluid stored in a machining tank.

[0002]

2. Description of the Related Art FIG. 6 is a system configuration diagram of a conventional immersion type electric discharge machining apparatus, and FIG. 7 is an explanatory diagram showing an enlarged part of FIG. 6 and 7, 1 is a wire electrode, 2 is a workpiece, 3 is an upper nozzle, 4 is a quill, 5 is a ball screw, 6 is a motor, 7 is a Z-axis mechanism, 8 is a lower nozzle, and 9 is a lower arm. 10 is a table. 11 is a working fluid, 1
2 is a processing tank, 13 is a processing liquid tank, 14 is a supply pump,
15 and 16 are pipes, 17 is a solenoid valve, 18 and 19 are pipes,
20 is a float switch. Further, in FIG. 7, 21 is a clamp jig, 22 is a fixing bolt, and 23 is an adjusting bolt.

Next, the operation of the above conventional device will be described. The work piece 2 is attached to the table 10, and the Z-axis mechanism 7 is driven according to a command from an NC device (not shown) according to the plate thickness of the work piece 2 to set the upper nozzle 3 immediately above the work piece 2.
Then, the processing liquid 11 in the processing liquid tank 13 is supplied to the processing tank 12 by the supply pump 14. When the working liquid 11 supplied into the working tank 12 increases and the float switch 20 detects the rise of the liquid level, the solenoid valve 17 opens and the working liquid 11 in the working tank 12 is discharged to the working liquid tank 13. When the liquid level in the processing tank 12 is lowered by discharging the processing liquid 11, the float switch 20 is closed and the electromagnetic valve 17 is closed to stop the discharging. In this way, the liquid level of the working liquid 11 in the working tank 12 is adjusted on and off to a certain range of height.

On the other hand, the wire electrode 1 is positioned relative to the workpiece 2 by the upper nozzle 3 and the lower nozzle 8. The work piece 2 immersed in the working liquid 11 in the working tank 12 is caused by the electric discharge between the wire electrode 1 and the work piece 2 and the relative movement of the wire electrode 1 and the work piece 2
Then, the electric discharge machining with a constant shape is performed.

[0005]

In the conventional immersion type electric discharge machining apparatus configured as described above, the amount of the machining liquid 11 supplied to the machining tank 12 is independent of the machining amount. In some cases, the amount of sludge contained in the working liquid 11 in the working tank 12 increased and the sludge concentration increased remarkably. For this reason, when the processing amount is large, the sludge concentration becomes high and the sludge is accumulated on the work piece 2,
The work piece 2 may cause chipping. Further, due to the increase in the sludge concentration, the working liquid 11 becomes turbid, and it may be difficult to observe the working state of the working portion.

As a preventive measure against these problems, it seems that the supply amount of the machining liquid 11 may be determined according to the machining amount at the time of maximum machining. The liquid 11 may be caused to flow, and the liquid flow may vibrate the wire electrode 1 to lower the machining accuracy, which is not preferable from the viewpoint of the machining accuracy and the utilization efficiency of the machining liquid. Further, since the sludge generated in the processing part is partially drifting, the processing liquid 11 to the processing tank 12
It has not been possible to constantly optimize the supply and discharge of. Further, as shown in FIG. 7, when it is attempted to process up to the end of the workpiece 2, the float switch 20 for liquid level detection is used.
However, there is a risk of collision with the clamp jig 21 and the fixing bolt 22. For this reason, it is necessary not only to pay sufficient attention not to collide with the bolt 22 or the like during processing, but also
There was a problem that the processing range was limited.

The present invention was made in order to solve the above-mentioned conventional problems, and an object thereof is to keep the sludge concentration in the processing tank constant at all times to eliminate dirt and maintain cleanliness. .. Another object is to make the liquid level detection mechanism that detects the height of the liquid level of the working liquid compact.

[0008]

According to the present invention, a working fluid in a working fluid tank is supplied to a working tank by a working fluid supply means, and a workpiece is dipped in the working fluid stored in the working tank for immersion processing. In an immersion type electric discharge machining apparatus, a machining amount calculation means for calculating a machining amount of a workpiece and a machining liquid supply amount controlled by a machining liquid supply means based on a calculation result of the machining amount calculation means are controlled. The immersion type electric discharge machining apparatus is provided with a supply amount control means.

Further, in the immersion type electric discharge machining apparatus for supplying the working fluid from the working fluid tank to the working tank by the working fluid supply means and immersing the workpiece in the working fluid stored in the working tank to perform the immersion machining, The machining amount calculation means for calculating the machining amount of the workpiece, the machining time measuring means for measuring the machining time from the start of machining of the workpiece, the machining time measured by the machining time measuring means and the machining amount calculating means for calculation. Concentration calculating means for calculating the sludge concentration in the processing tank from the processing amount, and supply amount control means for controlling the supply amount of the processing liquid supplied to the processing tank by the processing liquid supply means based on the calculation result of the concentration detecting means. This is a configuration of an immersion type electric discharge machine equipped with.

Further, the working fluid in the working fluid tank is supplied to the working tank by the working fluid supply means, the workpiece is immersed in the working fluid stored in the working tank, and the electrical condition set by the electrical condition setting means is set. In the immersion type electric discharge machine that processes according to the conditions etc., a concentration detection means for detecting the sludge concentration in the processing tank is provided, and the processing liquid supply means supplies the processing liquid to the processing tank based on the detection result of the concentration detection means. The immersion type electric discharge machining apparatus is provided with a supply amount control means for controlling the amount.

Further, the immersion type electric discharge machining apparatus is provided with stirring means for stirring the machining liquid in the machining tank.

Further, the wire electrode is positioned on the upper part of the work piece, and an upper nozzle for supplying the working liquid from the upper part of the work piece to the working part is provided. A part of the upper nozzle is immersed in the working liquid. In an electric discharge machining device for electrical discharge machining of a workpiece that has been immersed in a machining fluid with a wire electrode, a liquid level detection means for detecting the fluid level of the machining fluid in the machining tank is provided around the upper nozzle. This is a structure of a die electric discharge machine.

[0013]

Operation: When the work piece is mounted on the table, N
The C device drives the Z-axis mechanism so that the upper nozzle is positioned close to the work piece. After positioning the upper nozzle,
The supply pump is driven to supply the processing liquid in the processing liquid tank to the processing tank. Further, the machining amount is calculated from the machining conditions such as the electrical condition and the timekeeping function set by the NC device, and the machining liquid supply amount corresponding to the sludge generation amount is calculated. Then, the driving operation such as the rotation speed of the supply pump is selected, and the amount of the working fluid supplied as the calculation result is supplied to the working tank.

The supplied amount of the working liquid in the working tank is adjusted to a substantially constant range by the opening / closing operation of the electromagnetic valve by the liquid level detecting mechanism, and the workpiece is immersed in the stored working liquid.
Electric discharge is performed between the dipped work piece and the wire electrode fed from the positioned upper nozzle, and the work piece is electric discharge machined while relatively moving. During processing, the stirring mechanism agitates the working fluid in the working tank,
The distribution of sludge generated in the processing tank is made uniform as the processing progresses. When the amount of working fluid supplied is large, the operating frequency of the supply pump and the electromagnetic valve for discharge increases. In this way, when a large amount of sludge is generated, a large amount of machining fluid circulates in the machining fluid tank and the machining tank, and the sludge concentration is diluted to a low constant concentration.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. Example 1. FIG. 1 is a system configuration diagram showing an immersion type electric discharge machining apparatus according to a first embodiment of the present invention, and FIG. 2 is an explanatory diagram of a liquid level detection mechanism in the first embodiment. Although a part of the description is duplicated, the present invention will be described in some detail. In FIG. 1, 1 is a wire electrode, and 2 is a workpiece to be processed by the wire electrode 1. 3 is the work piece 2
The wire electrode 1 is positioned by the upper nozzle provided on the upper part of the. 4 is a quill for holding the upper nozzle 3, 5 is a ball screw, and 6 is a motor. The upper nozzle 3 and the quill 4 form a Z-axis mechanism. And Z
The motor 6 of the shaft mechanism 7 rotates the ball screw to move the upper nozzle 3 together with the quill 4 in the Z-axis direction to move the workpiece 2
To face.

Reference numeral 8 is a lower nozzle, and 9 is a lower arm.
The lower nozzle 8 is held by the lower arm 9, and the workpiece 2
The upper nozzle 3 is opposed to the upper nozzle 3. Reference numeral 10 is a table on which the workpieces 2 are loaded, 11 is a working fluid in which the workpieces 2 on the table 10 are immersed, and 12 is a working tank to which the working fluid 11 is supplied and stored. 13 is a processing fluid 11 equipped with a filtration mechanism
Fluid tank for storing, 14 is a supply pump, 15 and 1
6 is a pipe. The supply pump 14 is connected to the working liquid tank 13 and the working tank 12 by pipes 15 and 16, and supplies the working liquid 11 in the working liquid tank 13 to the working tank 12. 17
Is a solenoid valve, and 18 and 19 are pipes that connect the solenoid valve 17 to the processing tank 12 and the processing liquid tank 13. The electromagnetic valve 17 causes the machining fluid 11 in the machining tank 12 to flow back to the machining fluid tank 13 by opening and closing, and regulates the discharge amount of the machining fluid 11 stored in the machining tank 12.

A liquid level detecting mechanism 30 is provided around the upper nozzle 3, and a detailed explanatory view is shown in FIG. 31
Is a float of the liquid level detection mechanism 30, and 32 is a protective cover. The cover 32 is provided around the upper nozzle 3 on the same circumference, and the float 31 is arranged in an annular gap so as to be vertically movable. 33 is a movable contact mounted on the upper surface of the float 31, 34 is a fixed contact facing the movable contact 33 and integrated with the upper nozzle 3, and 35 is a seal ring. The seal ring 35 is provided between the float 31 and the cover 32 to slidably seal the float 31 and separate the movable contact 33 and the fixed contact 34 from the machining liquid 11.

Reference numeral 50 is an NC device. The NC device 50 is provided with various setting devices, for example, a machining voltage V, a current I,
Electrical conditions such as current duty ratio D are set.
Further, the NC device 50 is also provided with a time counting function for measuring the elapsed time from the start of processing of the workpiece 2 and various arithmetic / control functions. Then, the processing speed and the processing amount are obtained from the above electrical conditions, the measuring time, or the processing conditions such as the plate thickness of the workpiece 2, and the supply amount of the processing liquid corresponding to the amount of sludge generated during the processing is calculated. .. In addition, the NC device 50 also controls the start / stop operation of the Z-axis mechanism 7, the supply pump 14, the stirring mechanism 40, etc. based on the processing conditions.

The operation of the first embodiment of the present invention having the above configuration will be described below with reference to the flowchart of FIG. After attaching the work piece 2 to the table 10, the NC device 50
Command to drive the Z-axis mechanism 7 according to the plate thickness of the workpiece 2 to position the upper nozzle 3 close to the workpiece 2. After positioning, the supply pump 14 is operated to supply the working liquid 11 in the working liquid tank 13 to the working tank 12. When the working liquid 11 is supplied into the working tank 12 to raise the liquid level and float the float 31, the movable contact 33 and the fixed contact 34 come into contact with each other to be turned on. The ON signal of the contact is output to the solenoid valve 17 via the path shown by the arrows in FIGS. 1 and 2, and the solenoid valve 17 is opened to discharge the machining fluid 11 from the machining tank 12 to the machining fluid tank 13. When the liquid level in the processing tank 12 drops due to the discharge of the processing liquid 11, the float 31 also descends and the contact points 3 again.
3 and 34 are turned off, the solenoid valve 17 is also closed, and the discharge of the machining fluid 11 is stopped.

In this way, the liquid level detection mechanism 30 controls the liquid level of the working liquid 11 in the working tank 12 to be on / off within a certain range of height. The sludge and the like of the working fluid 11 returned to the working fluid tank 13 is filtered by a filtering mechanism, and then the purified working fluid 11 is supplied to the working tank 12 again by the supply pump 14.

On the other hand, the wire electrode 1 is suspended between the upper nozzle 3 and the lower nozzle 8 and positioned relative to the workpiece 2. Electric discharge machining is performed by causing an electric discharge between the wire electrode 1 and the workpiece 2 and moving the wire electrode 1 and the workpiece 2 relatively. During processing, the stirrer 41 is rotated by the motor 42 of the stirring mechanism 40,
By stirring the working liquid 11 in the working tank 12, the sludge concentration generated by the working is made uniform in the working tank 12.

The electrical processing conditions of the workpiece 2 are set by the NC device 50, and the processing speed is calculated from the set electrical processing conditions. Further, the processing amount is calculated from the calculated processing speed and the plate thickness of the workpiece 2. Since the amount of sludge generated depending on the processing amount is predicted, the processing tank 12
The supply amount of the working fluid 11 supplied to is calculated. The supply amount of the machining fluid 11 obtained as the calculation result can be selected by the NC device 50 from the rotation speed of the supply pump 14 to a predetermined amount. Thus, the supply amount of the processing liquid 11 supplied from the supply pump 14 to the processing tank 12 corresponds to the amount of generated sludge.

Example 2. In the above-described first embodiment, a configuration is adopted in which the supply amount of the working fluid 11 is once calculated and set and then not changed. Generally, since the sludge concentration in the processing tank 12 is low at the beginning of processing, the supply amount of the processing liquid 11 does not need to be so large. Further, even when the processing time is short, the supply of the processing liquid 11 may be reduced in some cases. Therefore, if the change in the sludge concentration inside the processing tank 12 is measured according to the elapsed processing time and the supply amount of the processing liquid 11 is changed according to the measured value, the supply of the processing liquid 11 can be performed more effectively. It will be.

Therefore, in the second embodiment of the present invention, the working fluid 11 is used.
The sludge concentration in the inside is calculated at regular time intervals, and the supply amount of the working liquid 11 is increased according to the working time. A flow chart showing the operation of the second embodiment is
As shown in FIG. 4 is different from FIG. 3 in that the calculation of the supply amount of the working fluid 11 based on the sludge concentration calculated for each elapsed processing time is cyclically repeated as shown in the flowchart.

Example 3. In the first embodiment, the supply amount of the working fluid 11 is determined by calculation using the NC device 50, but the sludge concentration in the working fluid 11 may be directly detected. The configuration of the third embodiment based on the actual measurement is shown in FIG. In FIG.
Reference numeral 60 is a sludge concentration detecting mechanism. Reference numeral 61 is a light emitting diode of the density detection mechanism 60, 62 is a phototransistor, and 63 is a controller. Both the light emitting diode 61 and the phototransistor 62 are waterproofed, and are arranged so as to face each other in the processing liquid 11 in the processing tank 12 at regular intervals. The light projected from the light emitting diode 61 is reflected or scattered by the sludge suspended in the working liquid 11, and the phototransistor 62 receives the attenuated light. The controller 63 uses the phototransistor 6
The supply amount of the working fluid 11 is controlled via the supply pump 14 according to the output of 2.

Next, the operation of the third embodiment will be described. The process is the same as in Example 1 until the processing is started. When the processing is started, sludge is generated and the processing liquid 11 in the processing tank 12 begins to become dirty. The processing tank 12 includes a stirrer 41 of a stirring mechanism 40.
Is installed, the motor 42 is driven, and the machining fluid 11
Are stirred and the sludge concentration is made uniform in the processing tank 12. Therefore, the sludge distribution in the processing tank 12 becomes uniform, and the sludge concentration may be detected anywhere. In the present invention, the sludge concentration is detected using light as follows.

The light projected from the light emitting diode 61 of the concentration detecting mechanism 60 installed inside the processing tank 12 passes through the processing liquid 11 and is received by the phototransistor 62.
The output of the phototransistor 62 that receives the transmitted light changes corresponding to the sludge concentration, and the output decreases when the sludge concentration becomes high. Further, when the sludge concentration in the working fluid 11 becomes thin, the output increases. And
The controller 63 increases the supply amount of the supply pump 14 when the sludge concentration becomes high based on the output of the phototransistor 62. On the contrary, when the sludge concentration becomes thin, the supply amount is reduced so that the sludge concentration in the processing tank 12 is controlled to be substantially constant. In the third embodiment, the sludge concentration is directly detected and the detected amount is supplied to the pump 1.
Since the servo system which returns to 4 and controls the supply amount of the working fluid 11 is adopted, the supply amount accurately follows the change of the sludge concentration.

In the third embodiment described above, the case where the sludge concentration is detected by using light has been described as an example, but the configuration may be such that the amount of the working fluid 11 supplied to the working tank 12 is controlled by the sludge concentration. For example, weight or magnetism may be used.

[0029]

INDUSTRIAL APPLICABILITY The present invention provides the immersion type electric discharge machining in which the working fluid in the working fluid tank is supplied to the working tank by the working fluid supply means, and the workpiece is immersed in the working fluid stored in the working tank to perform the dipping processing. In the apparatus, a processing amount calculation means for calculating a processing amount of a workpiece, and a supply amount control means for controlling a supply amount of a processing liquid supplied to a processing tank by a processing liquid supply means based on a calculation result of the processing amount calculation means. And a submerged electric discharge machine comprising:

Further, in the immersion type electric discharge machining apparatus for supplying the working fluid from the working fluid tank to the working tank by the working fluid supply means and immersing the workpiece in the working fluid stored in the working tank to perform the immersion machining, The machining amount calculation means for calculating the machining amount of the workpiece, the machining time measuring means for measuring the machining time from the start of machining of the workpiece, the machining time measured by the machining time measuring means and the machining amount calculating means for calculation. Concentration calculating means for calculating the sludge concentration in the processing tank from the processing amount, and supply amount control means for controlling the supply amount of the processing liquid supplied to the processing tank by the processing liquid supply means based on the calculation result of the concentration detecting means. This is a configuration of an immersion type electric discharge machine equipped with.

Further, the working fluid in the working fluid tank is supplied to the working tank by the working fluid supply means, the workpiece is dipped in the working fluid stored in the working tank, and the electrical condition set by the electrical condition setting means is set. In the immersion type electric discharge machine that processes according to the conditions etc., a concentration detection means for detecting the sludge concentration in the processing tank is provided, and the processing liquid supply means supplies the processing liquid to the processing tank based on the detection result of the concentration detection means. The immersion type electric discharge machining apparatus is provided with a supply amount control means for controlling the amount.

Further, the immersion type electric discharge machining apparatus is provided with a stirring means for stirring the machining liquid in the machining tank.

Further, the wire electrode is positioned on the upper part of the work piece, and an upper nozzle for supplying the working liquid from the upper part of the work piece to the working part is provided. A part of the upper nozzle is immersed in the working liquid. In an electric discharge machining device for electrical discharge machining of a workpiece that has been immersed in a machining fluid with a wire electrode, a liquid level detection means for detecting the fluid level of the machining fluid in the machining tank is provided around the upper nozzle. A die electric discharge machine was constructed.

As a result, a small amount of working liquid is supplied at the time of finishing such as a small working amount, and a large amount of working liquid is supplied to the working tank when the plate thickness is thick or the working speed is fast, so that the sludge concentration is always uniform. Will be held in. Therefore, the workpiece does not cause chipping, and the sludge concentration increases so that the working fluid becomes turbid and does not hinder the observation of the working state of the working portion. Further, since the supply of the processing liquid corresponds to the sludge amount, that is, the processing speed, the supply is appropriate, the utilization efficiency is high, and the processing accuracy can be improved. In addition, the installation of stirring means makes the distribution of sludge uniform, the liquid level detector is compact, and the conventional float switch can eliminate the risk of collision with clamp jigs and fixing bolts, and the processing range. You can

Therefore, according to the present invention, the sludge concentration in the processing tank is always kept constant and clean, the utilization efficiency of the processing liquid is high, and the processing of the workpiece can be performed with high accuracy. It is possible to provide an immersion type electric discharge machine having the advantages of

[Brief description of drawings]

FIG. 1 is a system configuration diagram showing an immersion electric discharge machining apparatus according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram of a liquid level detection device according to the first embodiment.

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

FIG. 4 is a flowchart showing an operation according to the second embodiment of the present invention.

FIG. 5 is a system configuration diagram showing another embodiment of the present invention.

FIG. 6 is a system configuration diagram in a conventional immersion electric discharge machine.

FIG. 7 is an explanatory diagram of the vicinity of a workpiece in a conventional immersion type electric discharge machining apparatus.

[Explanation of symbols]

1 Wire Electrode 2 Workpiece 3 Upper Nozzle 11 Processing Liquid 12 Processing Tank 13 Processing Liquid Tank 14 Supply Pump (Processing Liquid Supply Means) 30 Liquid Level Detection Mechanism (Liquid Level Detection Means) 40 Stirring Mechanism (Stirring Means) 50 NC Device (Electrical condition setting means, processing amount calculation means, processing time measurement means, concentration calculation means, supply amount control means) 60 Concentration detection mechanism (concentration detection means)

Claims (5)

[Claims] 1. An immersion type electric discharge machining apparatus for supplying a working fluid from a working fluid tank to a working tank by a working fluid supply means, and immersing a workpiece in the working fluid stored in the working tank for immersion machining. Processing amount calculation means for calculating the processing amount of the workpiece, and supply amount control means for controlling the supply amount of the processing liquid supplied to the processing tank by the processing liquid supply means based on the calculation result of the processing amount calculation means. An immersion type electric discharge machine comprising: 2. An immersion type electric discharge machining apparatus for supplying a machining fluid from a machining fluid tank to a machining tank by a machining fluid supply means, immersing a workpiece in the machining fluid stored in the machining tank, and performing immersion machining. Machining amount calculating means for calculating the machining amount of the workpiece, machining time measuring means for measuring the machining time from the start of machining of the workpiece, machining time measured by the machining time measuring means and the machining amount The concentration calculation means for calculating the sludge concentration in the processing tank from the processing amount calculated by the calculation means, and the supply amount of the processing liquid supplied to the processing tank by the processing liquid supply means based on the calculation result of the concentration detection means. An immersion type electric discharge machining apparatus comprising: a supply amount control means for controlling. 3. The electricity set by the electrical condition setting means by supplying the working fluid from the working fluid tank to the working tank by the working fluid supply means and immersing the workpiece in the working fluid stored in the working tank. In an electric discharge machining apparatus for machining under mechanical conditions, a concentration detecting means for detecting sludge concentration in the machining tank, and a machining liquid supplied to the machining tank by the machining liquid supplying means based on a detection result of the concentration detecting means. And a supply amount control means for controlling the supply amount of the immersion type electric discharge machining apparatus. 4. The immersion electric discharge machining apparatus according to claim 1, further comprising stirring means for stirring the machining liquid in the machining tank. 5. An upper nozzle for positioning the wire electrode on the upper part of the work piece and supplying the working liquid to the working part from the upper part of the work piece, and part of the upper nozzle is the working liquid. In an electric discharge machining apparatus for electrical discharge machining of a workpiece immersed in a machining fluid by immersing it in a wire electrode, a liquid level detecting means for detecting the liquid level of the machining fluid in the machining tank on the outer periphery of the upper nozzle. An immersion type electric discharge machine characterized by being provided with.