JPH1015741A - Electric discharge machining method and device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a work from being strongly pressed by an electrode by performing electric discharge machining for a work by a pipe-like electrode, and stopping the feed of the electrode on detecting that the electrode is brought into contact with an insulator to stop electric discharge machining. SOLUTION: When feed is given to an electrode 19, the electrode 19 is bent while being rotated, and a little bent to a V-shaped notch part 31 side in an oscillation preventing member 27 to come into contact with a sensor 35 of the inside edge. When the electrode 19 comes into contact with the sensor 35, the lower end part of the electrode 19 is brought into contact with an insulator WI to be detected as the occurrence of bending in the electrode 19, and the feed for the electrode by a servo motor 5 is stopped to stop electric discharge machining. Accordingly, it is possible to prevent the electrode 19 from being largely bent to be broken.

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 method and apparatus for forming a hole in a work using a pipe-shaped electrode, and more particularly, to an electric discharge machining method for a work integrally provided with an insulator. And an apparatus.

[0002]

2. Description of the Related Art An electric discharge machine for forming a hole in a work using a pipe-shaped electrode has an electrode holder provided on a machining head which is moved up and down by driving a servomotor, and an upper end portion is held by the electrode holder. The lower end of the pipe-shaped electrode is opposed to the work, a discharge is generated between the lower end of the electrode and the work, and a hole is formed in the work by ejecting a machining flow from the electrode.

[0003]

When the above-mentioned conventional electric discharge machining apparatus performs electric discharge machining on a work integrally provided with an insulator such as diamond, ceramics, rubber or the like, the electrodes reach the insulator. Then, since no current is supplied, the servomotor is driven and controlled so as to feed the electrode assuming that the distance between the work and the lower end of the electrode is large.

[0004] Accordingly, the electrode or the electrode may be strongly pressed against the work, thereby damaging the work or the electrode, and applying a large load to the servo motor side. Is not performed by electric discharge machining.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and the invention according to claim 1 performs electric discharge machining on a workpiece using a pipe-shaped electrode. This is an electric discharge machining method in which the feed of the electrode is stopped to stop the electric discharge machining when it is detected that the electrode has contacted the insulator.

According to a second aspect of the present invention, the workpiece is subjected to electrical discharge machining using a pipe-shaped electrode, and when it is detected that the electrode has come into contact with the insulator, the feed of the electrode is stopped, and the discharge is stopped. This is an electric discharge machining method in which the above-mentioned stop state is maintained until no more occurs.

According to a third aspect of the present invention, an electrode holder is provided on a machining head which is moved up and down by driving a servomotor, and a lower end of an electrode whose upper end is held by the electrode holder abuts on an insulator. When the electrode is bent,
This is an electric discharge machining apparatus provided with a sensor for detecting the deflection.

According to a fourth aspect of the present invention, there is provided an electrode mounted on an electrode holder provided on the processing head, the processing head being provided on a slider which is moved up and down by driving of a servomotor. An electric discharge machining apparatus comprising: an urging support device for urging and supporting the machining head upward to support the weight of the head; and a sensor for detecting a relative rise of the machining head with respect to the slider. .

According to a fifth aspect of the present invention, in the fourth aspect of the present invention, the biasing support device is provided so as to be capable of adjusting an upward biasing force.

According to the first aspect of the present invention, electric discharge machining is performed on a workpiece by using a pipe-shaped electrode, and when it is detected that the electrode comes into contact with an insulator, the feed of the electrode is stopped and the electric discharge machining is stopped. Is an electric discharge machining method for stopping the operation.

Therefore, a hole is formed in the work by electric discharge machining, and the tip of the electrode comes into contact with the insulator. When this contact is detected, the feeding of the electrode is stopped. Therefore, it is possible to prevent the workpiece from being strongly pressed by the electrode.

According to a second aspect of the present invention, electric discharge machining is performed on a workpiece using a pipe-shaped electrode, and when it is detected that the electrode has come into contact with an insulator, the feeding of the electrode is stopped, so that no discharge occurs. This is an electric discharge machining method in which the above-mentioned stopped state is maintained until the above.

Therefore, when a hole is formed in the work and it is detected that the lower end of the electrode has come into contact with the insulator, the feeding of the electrode is stopped. Then, the stopped state is maintained until the discharge stops.

Therefore, the work is not strongly pressed by the electrode, so that the work and the electrode are prevented from being damaged, and the lower end of the machining hole formed by the electric discharge machining is accurately machined.

According to a third aspect of the present invention, an electrode holder is provided on a machining head that is moved up and down by driving a servomotor, and a lower end of an electrode whose upper end is held by the electrode holder is in contact with an insulator. When the electrode is bent,
This is an electric discharge machining apparatus provided with a sensor for detecting the deflection.

Therefore, when the lower end portion of the electrode comes into contact with the insulator during electric discharge machining of the workpiece, and the feed is further applied to cause the electrode to bend, the sensor detects the bending. Therefore, it is possible to immediately stop the feeding of the electrode when the sensor detects the above, and it is possible to prevent the electrode and the workpiece from being damaged.

According to a fourth aspect of the present invention, there is provided an electrode mounted on an electrode holder provided on the processing head, wherein the processing head is provided on a slider which is moved up and down by driving a servomotor. An electric discharge machining apparatus comprising: an urging support device for urging and supporting the machining head upward to support the weight of the head; and a sensor for detecting a relative rise of the machining head with respect to the slider. .

Therefore, when the lower end of the electrode comes into contact with the insulator during electric discharge machining, the head rises relatively to the slider, and this rise is detected by the sensor. Therefore, the feed of the electrode can be immediately stopped when the relative elevation of the processing head is detected by the sensor, and damage to the workpiece and the electrode can be prevented.

According to a fifth aspect of the present invention, in the fourth aspect of the present invention, the biasing support device is provided so as to be capable of adjusting the upward biasing force.

Therefore, when the weight changes due to the change of the electrode, the biasing force can be adjusted to correspond to the above-mentioned weight, and the relative rise of the processing head when the electrode comes into contact with the insulator is smoothly performed. be able to.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown conceptually in FIG. 1, an electric discharge machine 1 according to the present embodiment has a vertical position corresponding to the height of a work W arranged in a machining tank (not shown). An adjustable lifting frame 3 is provided, on which a ball screw 7 rotated by a servomotor 5 is rotatably supported. A ball nut 11 provided integrally with the slider 9 is screwed to the ball screw 7 so as to be vertically movable, and the slider 9 is configured to be vertically moved by the rotational drive of the servo motor 5.

The slider 9 is provided with a processing head 13 on which an electrode holder 17 rotated by a motor 15 is rotatably mounted. The electrode holder 17 includes a chuck for detachably holding an upper end of a pipe-shaped electrode 19 for performing electric discharge machining on the work W.

An electrode guide portion 21 having a vertical guide hole (not shown) for guiding the electrode 19 is provided at a lower portion of the elevating frame 3. A bracket 23 provided on the lifting frame 3 at a position above the electrode guide portion 21
Is provided with an up-down guide rod 25, and on this guide rod 25, a vibration preventing member 27 for preventing rotation vibration of the electrode 19 is vertically movably supported.

As shown in FIG. 2, the anti-sway member 27 is formed in a plate-like shape having a fitting portion 29 on the base side, which is fitted to the guide rod 23 with proper friction so as not to fall by its own weight. A V-shaped notch 31 is formed at the tip of the shake preventing member 27. An arc-shaped concave portion 33 having a diameter slightly larger than the diameter of the electrode 19 is formed at the bottom of the notch 31 (the bottom of the V-shaped portion) in order to regulate and suppress the deflection of the electrode 19. Further, a sensor 35 for detecting the contact of the electrode 19 is provided on the inner edge of the V-shaped notch 31.

This sensor 35 is for detecting that the electrode 19 has been bent, and it is only necessary to be able to detect that the electrode 19 has been bent and a large displacement has occurred from the concave portion 33. For example, it is desirable to use a contact sensor.

In the above configuration, the work W integrally provided with the insulator WI is disposed in the processing tank, the upper end of the electrode 19 is mounted on the electrode holder 17 provided on the processing head 13, and the motor 15 is driven. The electrode 19 is rotated by the rotation of the servo motor 5 and the slider 19 is lowered to feed the electrode 19, the electrode 19 is guided by the electrode guide portion 21, and a machining flow is ejected from the lower end of the electrode 19. However, by performing discharge between the electrode 19 and the work W, a work hole corresponding to the outer diameter of the electrode 19 is formed in the work W.

When the rotation of the electrode 19 tends to swing near the center of the electrode 19, the swing preventing member 2
The deflection of the electrode 19 is suppressed by the arcuate concave portion 33 of FIG.

When the lower end portion of the electrode 19 abuts on the insulator WI provided on the work W as the electric discharge machining of the work W proceeds, no discharge occurs between the work W and the electrode 19, so that the work W Assuming that the distance (clearance) from the lower end of the electrode 19 is large, the servo motor 5 feeds the electrode 19 to reduce the clearance.

When feed is applied to the electrode 19 as described above, the electrode 19 is curved while rotating, and slightly curved toward the V-shaped notch 31 side of the vibration preventing member 27, and It contacts the sensor 35. When the electrode 19 comes into contact with the sensor 35 as described above, the lower end of the electrode 19 contacts the insulator WI and detects that the electrode 19 is bent, and the servo motor 5 stops feeding the electrode 19 and discharges. Stop machining. Thereafter, the machining head 13 is returned to the original raised position by rotating the servo motor 5 in the reverse direction, and the electrode 19 can be separated from the work W.

Therefore, it is possible to prevent the electrode 19 from being greatly bent and damaged. In other words, even in the case of the work W provided with the insulator WI, the electric discharge machining of the hole can be performed in the metal portion without damaging the electrode 19 and the like.

When the electrode 19 is thin and easily bent as described above, the lower end of the electrode 19 comes into contact with the insulator WI provided on the workpiece W by detecting the bending of the electrode 19. Can be detected.
Therefore, it is also possible to provide a ring surrounding the electrode 19 and provide a contact sensor or the like on this ring to detect the deflection of the electrode 19.

The sensor only needs to detect that the electrode 19 is bent and deviated from a predetermined position, and an optical sensor, a magnetic sensor, a limit switch, or the like may be used.

FIG. 3 shows that, for example, the electrode 19 is thick,
3 shows a configuration capable of coping with a case where bending is unlikely to occur even when the lower end of the workpiece W contacts the insulator WI of the work W. In this example, components having the same functions as those of the above-described configuration are denoted by the same reference numerals, and redundant description will be omitted.

In this embodiment, a construction different from the above-mentioned construction is such that the machining head 13 is provided on the slider 9 so as to be movable up and down relatively, and the machining head 13 is designed to support the weight of the machining head 13 and the electrode 19. 13 is provided with a biasing support device 37 that biases and supports the upward direction.

More specifically, the slider 9 is provided with a protrusion 41 capable of supporting a bracket 39 provided on the processing head 13 from below, and the protrusion 41 has a hole 43 opened upward. It is provided. An upper portion of an elastic member 45 such as a coil spring provided in the hole 43 comes into contact with an urging force adjusting member 47 such as a screw member which is screwed to the bracket portion 39 of the processing head 13 so as to be vertically adjustable. is there.

Therefore, the urging force of the elastic member 45 is applied by the urging force adjusting member 47 to the working head 13 and the electrode 1.
By adjusting to balance with the weight of 9 mag,
When a slight upward external force acts on the processing head 13, the processing head 13 can be raised relatively smoothly with respect to the slider 9.

In order to detect the relative rise of the processing head 13 with respect to the slider 9, a sensor 49 such as a limit switch is provided at an appropriate position of the slider 9.
Is provided.

In the above configuration, the electric discharge machining is performed on the work W in the same manner as described above, and the insulator WI provided on the work W is provided.
After the lower end of the electrode 19 abuts on the slider 19, if the slider 9 is further lowered by the servomotor 5 to feed the electrode 19, the electrode 19 is relatively thick and hardly bent. In this case, The processing head 13 is raised relatively to the slider 9. In this case, since the processing head 13 is supported by the slider 9 via the urging support device 37 so as to be able to move up and down, the processing head 13 is relatively raised by a slight external force.

When the relative elevation of the processing head 13 with respect to the slider 9 is detected by the sensor 49, the feed of the electrode 19 by the servo motor 5 is stopped. Immediately after the lower end of the electrode 19 contacts the insulator WI as described above, a burr-like portion WB is formed between the lower end of the processing hole WH formed in the workpiece W and the electrode 19, as shown in FIG. Will remain,
The state in which the feed of the electrode 19 by the servomotor 5 is stopped is maintained until the burr-shaped portion WB is subjected to electric discharge machining so that no discharge occurs (until spark out).

In this case, since the electrode 19 is relatively thick and is held almost vertically without causing large bending, the feeding of the electrode 19 is stopped until the burr-shaped portion WB is subjected to electric discharge machining. But there is no big problem.

If the machining accuracy of the machining hole WH is not required, the servomotor 45 is stopped immediately after the detection operation of the sensor 49, the feed of the electrode 19 is stopped, and the flash portion WB is subjected to electric discharge machining. Servo motor 5 without any
It is also possible to reverse the rotation to return to ascending. Further, it is also possible to use a timer or the like, and after the sensor 49 performs the detection operation, the servo motor 5 is rotated in the reverse direction after the set time of the timer elapses, and the machining head 13 is raised and returned.

In this embodiment, the urging support device 37
The structure of the elastic member 4 such as a coil spring
Although the configuration using No. 5 has been described, the configuration of the biasing support device 37 is such that a magnet is provided on each of the slider 9 and the processing head 13 in order to utilize the repulsive force of the magnets of the same polarity. It is also possible. Furthermore, it is also possible to adopt a configuration in which the processing head 13 is suspended using a pulley and a weight. Further, it is also possible to provide a structure in which a fluid pressure mechanism such as an air spring is provided on the slider 9 and the processing head 13 is vertically movably supported by the fluid pressure mechanism. In this case, by adjusting the fluid pressure, it is possible to cope with a change in the weight of the processing head or the like.

In the above description, the case where the electrode 19 is rotated has been exemplified. However, if the cross-sectional shape of the electrode 19 is not circular, the electrode 19 is of course not rotated.

[0044]

As will be understood from the above description, in short, in the first aspect of the present invention, electric discharge machining is performed on a workpiece using a pipe-shaped electrode, and the electrode comes into contact with an insulator. Since this is an electric discharge machining method in which the feed of the electrode is stopped to stop the electric discharge machining when it is detected, the electrode is not strongly pressed by the work, and the electrode and the work are prevented from being damaged. be able to.

According to a second aspect of the present invention, the workpiece is subjected to electrical discharge machining using a pipe-shaped electrode, and when it is detected that the electrode has come into contact with the insulator, the feed of the electrode is stopped, and the discharge is stopped. Since the above-mentioned stop state is maintained until no more occurs, it is possible to prevent the work from being pressed by the electrode, and to accurately process the lower end portion of the machining hole by the electric discharge machining.

According to a third aspect of the present invention, an electrode holder is provided on a machining head which is moved up and down by driving of a servomotor, and a lower end of an electrode whose upper end is held by the electrode holder is in contact with an insulator. When the electrode is bent,
Since the sensor for detecting the deflection is provided, when the sensor detects the deflection of the electrode, the feed of the electrode can be stopped immediately, and the problem of pressing the workpiece with the electrode. Does not occur.

According to a fourth aspect of the present invention, a machining head is provided on a slider which is vertically moved by driving a servomotor so as to be relatively vertically movable, and an electrode mounted on an electrode holder provided in the machining head and the machining head are provided. A biasing support device for biasing and supporting the processing head upward to support the weight of the head is provided, and a sensor for detecting a relative rise of the processing head with respect to the slider is provided. When the electrode comes into contact with the workpiece and the processing head rises relatively to the slider, the above-mentioned rise can be detected by a sensor, and the feed of the electrode can be stopped immediately upon detection.
Therefore, the work is not strongly pressed by the electrode.

According to a fifth aspect of the present invention, in the fourth aspect of the present invention, the biasing support device is provided so that the upward biasing force can be adjusted. Even if the weight changes, it can be easily handled.

[Brief description of the drawings]

FIG. 1 is an operation explanatory view conceptually showing an electric discharge machine according to the present invention.

FIG. 2 is an explanatory diagram of a shake preventing member.

FIG. 3 is an explanatory view showing a support structure of a processing head for a slider.

FIG. 4 is an explanatory view of a processing hole of a work.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electric discharge machine 5 Servo motor 9 Slider 13 Machining head 17 Electrode holder 19 Electrode 27 Anti-shake member 35 Sensor 37 Urging support device 45 Elastic member 47 Urging force adjusting member 49 Sensor

Claims (5)

[Claims] An electric discharge machining is performed on a workpiece using a pipe-shaped electrode, and when it is detected that the electrode comes into contact with an insulator, the feed of the electrode is stopped to stop the electric discharge machining. Electrical discharge machining method. 2. A discharge machining is performed on a workpiece using a pipe-shaped electrode, and when it is detected that the electrode has come into contact with an insulator, the feed of the electrode is stopped, and the stopped state is maintained until no discharge occurs. An electric discharge machining method characterized by holding. 3. An electrode holder is provided on a processing head which is moved up and down by driving of a servomotor, and a lower end of an electrode whose upper end is held by the electrode holder abuts on an insulator to cause bending of the electrode. And a sensor for detecting the deflection when the electric discharge machining is performed. 4. A processing head is provided on a slider which is moved up and down by driving a servo motor so as to be able to move up and down relatively.
An urging support device for urging and supporting the processing head in an upward direction so as to support an electrode mounted on an electrode holder provided in the processing head and the weight of the processing head, and a relative position of the processing head with respect to the slider; An electric discharge machine characterized by comprising a sensor for detecting an excessive rise. 5. The electric discharge machining apparatus according to claim 4, wherein the urging support device is provided so as to adjust an upward urging force.