JP2000036629A - Method for detecting abnormal discharge from laser oscillator, laser oscillator, and method for discriminating fault of abnormal discharge detecting means for laser oscillator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid damage to an electrode by abnormal discharge by making the abnormal discharge detectable by means of the other detecting circuit system when one detecting circuit system becomes unoperatable. SOLUTION: In a method for detecting abnormal discharge from a laser oscillator, a detection bar 15 which is an abnormal discharge receiving member is incorporated in a vacuum vessel 3 and a first abnormal discharge detecting system which recognizes the occurrence of abnormal discharge when discharge is made to the bar 15 and a second abnormal discharge detecting system which recognizes the occurrence of abnormal discharge when the output value of the laser oscillator found by arithmetically processing the laser light emitted from the oscillator becomes different from the laser output command value given to an oscillator control section 11 are provided so that the two systems may detect the abnormal discharge.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for detecting abnormal discharge in a laser oscillator, a laser oscillator, and a method for determining a failure in abnormal discharge detection means in a laser oscillator. An object of the present invention is to provide a method for detecting abnormal discharge in a laser oscillator, a method for detecting abnormal discharge in a laser oscillator, and a method for determining a failure in abnormal discharge detection means in a laser oscillator, which is detected by a discharge detection system to prevent electrode damage.

[0002]

2. Description of the Related Art For example, as shown in FIG. 2, a laser oscillator of a laser processing apparatus for cutting or welding a work includes a pair of electrodes 103, 103 in a vacuum vessel 101.
Are disposed facing each other with a predetermined distance, and these electrodes 103, 1
A predetermined voltage is applied by the high-voltage power supply unit 105 during 03.
A laser medium (not shown) provided in the vacuum vessel 101 is excited to emit laser light.

[0003] The output of the laser light is output from an NC unit 107.
Is issued to the oscillator control unit 109. Upon receiving the laser output command, the oscillator control section 109 drives the high-voltage power supply section 105 to instruct a predetermined voltage to be applied between the pair of electrodes 103. As a result, a laser beam corresponding to the output command is output.

By the way, in the laser oscillator of the laser processing apparatus having the above-described configuration, when air leak or water leak into the vacuum vessel 101 occurs, normal discharge cannot be performed, and the discharge shifts to abnormal discharge. When the discharge is normal, the discharge is normally performed between the electrodes 103. However, when the discharge is abnormal, the discharge is performed to the frame of the vacuum vessel 101 or the like.

[0005]

If the discharge is continued as it is, the electrodes 103 may be damaged in a few seconds to a few tens of seconds. In order to prevent this, for example, as shown in FIG. 2, a detection bar 111 for discharging the electric charge when an abnormal discharge occurs inside the vacuum vessel 101 is provided, and the detection of the discharge by the detection bar 111 is detected. An abnormal discharge detection circuit 113 is provided. The oscillator control unit 109 stops the voltage application by the high voltage power supply unit 105 to stop the abnormal discharge, and simultaneously outputs an alarm to the NC unit 107 to stop machining. Provided.

However, if the detection bar 111 breaks, the abnormal discharge detection circuit 113 fails, or the alarm detection level is set incorrectly, the abnormal discharge cannot be detected and the electrodes 103 are also damaged. There is a fear.

[0007]

As described above, in the laser oscillator, although a circuit system for detecting abnormal discharge is provided, abnormal discharge is detected when there is a disconnection of the detection bar 111, although it is rare. Will be impossible,
In the present invention, two abnormal discharge detection systems are provided so that abnormal discharge can be detected by another detection system even if one detection system stops operating.

By providing two circuits for detecting abnormal discharge, it is possible to detect abnormal discharge in the other system even if one of the detection circuits does not operate for some reason. Damage is avoided.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments to which the present invention is applied will be described in detail with reference to the drawings.

As shown in FIG. 1, a laser oscillator according to the present embodiment has a vacuum vessel 3 in which a pair of electrodes 1 and 1 are arranged to face each other and a laser medium (not shown) is provided.
A high-voltage power supply unit 5 for applying a predetermined voltage between the electrodes 1 and 1; an optical sensor 7 for receiving the emitted laser light; and an amplifier for amplifying the laser light received by the optical sensor 7. A certain amplifier 9, an oscillator control unit 11 which drives and controls the high-voltage power supply unit 5, performs arithmetic processing on the laser light amplified by the amplifier 9, and outputs a laser output value; An NC device 13 which is a control device to which a laser output value is input from the control unit 11, a detection bar 15 which is an abnormal discharge receiving member arranged in the vacuum vessel 3, and that abnormal discharge has been performed on the detection bar 15. And an abnormal discharge detecting circuit 17 for detecting the abnormal discharge.

A high-voltage power supply 5 for applying a high-voltage to excite the laser medium is connected to the pair of electrodes 1 and 1 which are opposed to each other at a predetermined distance in the vacuum vessel 3. The high-voltage power supply unit 5 includes the oscillator control unit 1
1 is controlled by the oscillator control unit 11 so as to be turned on / off. The oscillator control unit 11 receives a laser output command from the NC device 13 and drives the high-voltage power supply unit 5 according to the laser output command.

The optical sensor 7 is provided on an extension of an optical path from which the laser light is emitted so as to receive the laser light emitted from the vacuum vessel 3. The laser light received by the optical sensor 7 is amplified by the amplifier 9 and sent to the oscillator control unit 11. The oscillator control section 11 performs arithmetic processing on the amplified laser light and inputs it to the NC device 13 as a laser output value.

In the laser oscillator of the present embodiment, when an abnormal discharge occurs in the vacuum vessel 3, two detection systems (detection means) are provided as detection circuits for detecting the abnormal discharge state. I have. One of them is that when an abnormal discharge occurs in the vacuum vessel 3, the charge is discharged to a detection bar 15 arranged in the vacuum vessel 3, and that the discharge of the detection bar 15 is controlled by the oscillator control. A first abnormal discharge detection system (first abnormal discharge detecting means) in which the oscillator control unit 11 notifies the unit 11 and issues a command to stop the voltage application to the high voltage power supply unit 5 to stop the abnormal discharge.
It is.

The other is that when the laser output command value and the laser output value become different values, the oscillator control section 11 issues a command to the high voltage power supply section 5 to stop voltage application. Abnormal discharge was stopped.
It is a second abnormal discharge detection system (second abnormal discharge detection means).

In the laser oscillator having the two abnormal discharge detection systems, when a laser output command is issued from the NC unit 13 to the oscillator control unit 11, the oscillator control unit 11 drives the high voltage power supply unit 5. Then, a predetermined voltage is applied between the electrodes 1 and 1 to cause a discharge, and the discharge excites a laser medium to emit a laser beam outward from the vacuum vessel 3. When the discharge is performed normally, the laser beam is emitted from the NC device 13 according to the laser output command given to the oscillator control unit 11. Therefore, the laser output value of the laser light received by the optical sensor 7 is substantially equal to the laser output command value. In the laser oscillator of the present embodiment, the high-voltage power supply unit 5 is drive-controlled by the oscillator control unit 11 so that the laser output command value and the laser output value are substantially the same.

However, if air leak or water leak into the vacuum vessel 3 occurs, normal discharge is not performed, and abnormal discharge occurs as indicated by a dotted arrow in FIG. It is discharged to the frame of the container 3. When the detection bar 15 is discharged, the abnormal discharge detection circuit 17 detects the discharge and notifies the oscillator control unit 11 that the abnormal discharge has occurred. Then, the oscillator control unit 11 issues a command to the high-voltage power supply unit 5 to stop the voltage application, stops the abnormal discharge, and simultaneously outputs an alarm to the NC device 13 to stop the machining.

On the other hand, when an abnormal discharge occurs, the optical sensor 7, which receives the laser light that is constantly emitted, receives a laser light having a smaller output than that in the normal discharge. The laser light is amplified by the amplifier 9 and sent to the oscillator control unit 11, where it is processed and input to the NC unit 13 as a laser output value. At this time, the laser output value is smaller than the laser output command value, that is, a value different from the laser output command value. When the difference between the laser output command value and the laser output value is equal to or more than a predetermined value, the oscillator control unit 11
When the high-voltage power supply unit 5 cannot be controlled, the present system
This time is determined to be abnormal, and the voltage application by the high voltage power supply unit 5 is stopped.

In the laser oscillator according to the present embodiment, two abnormal discharge detection systems (abnormal discharge detection means) are provided. Therefore, even if one of the detection systems stops operating, the other detection system operates. Therefore, occurrence of abnormal discharge can be detected, and the abnormal discharge can be stopped. Therefore, without damaging the electrodes 1 and 1,
In addition, there is no possibility that the laser oscillator is stopped to cause a processing failure of the work.

When only one of the detection systems has operated, it can be determined that the other detection system has failed, and when both of the detection systems have not operated, it can be determined that both have failed. For example, when only the first abnormal discharge detecting means operates, the second abnormal discharge detecting means has failed. Conversely, when only the second abnormal discharge detecting means operates, the first abnormal discharge detecting means has failed. It is determined that the detection means has failed. And
If both the first and second abnormal discharge detecting means do not operate, it is determined that both of them have failed.

Although a specific embodiment to which the present invention is applied has been described above, the present invention can be variously modified without being limited to the above-described embodiment.

[0021]

The present invention is embodied in the form described above and has the following effects.

According to the abnormal discharge detecting method for a laser oscillator of the present invention, two abnormal discharge detecting systems for detecting abnormal discharge are prepared and the abnormal discharge is detected by the two systems. Even if the detection system becomes abnormal, the other detection system detects abnormal discharge, so that damage to the electrodes can be avoided and machining defects of the work can be eliminated.

According to the laser oscillator of the present invention, when an abnormal discharge is detected by the abnormal discharge detection circuit, the oscillator control unit issues a command to stop the voltage application to the power supply unit to stop the abnormal discharge. When the output command value and the laser output value become different values, the oscillator control unit issues a command to stop the voltage application by the power supply unit to stop the abnormal discharge, that is, the abnormal discharge is detected by two abnormal discharge detection units. Because it is configured to detect
Even if one of the detecting means does not operate for some reason, the other detecting means operates. Therefore, the abnormal discharge can be detected and the discharge can be stopped immediately to avoid damage to the electrodes.

According to the failure determination method for abnormal discharge detecting means in the laser oscillator of the present invention, when only one of the two detecting means operates, it is determined that the other detecting means is faulty and both detecting means are faulty. If it has not operated, it can be determined that both of the detection means are faulty.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a schematic configuration of a laser oscillator according to the present embodiment in which two abnormal discharge detection circuits are provided.

FIG. 2 is a block diagram showing a schematic configuration of a conventional laser oscillator having one system of an abnormal discharge detection circuit.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electrode 3 Vacuum container 5 High voltage power supply part 7 Optical sensor 9 Amplifier 11 Oscillator control part 13 NC device 15 Detection bar 17 Abnormal discharge detection circuit

Claims (4)

[Claims] An oscillator control section drives a power supply section in response to a laser output command from a control device to apply a voltage between a pair of electrodes arranged in a vacuum vessel and discharge the laser light, thereby causing the vacuum vessel to emit laser light. The laser light is received by an optical sensor and sent to the oscillator control unit, and the laser control unit performs arithmetic processing on the laser light and inputs the laser output value to the control unit. A laser oscillator that is driven and controlled so that the output value substantially matches, wherein an abnormal discharge receiving member is provided in the vacuum vessel, and when the abnormal discharge receiving member is discharged, an abnormal discharge occurs. A first abnormal discharge detection system, and a second abnormal discharge detection system when an abnormal discharge occurs when the laser output command value and the laser output value are different from each other by a predetermined value or more. And a system, abnormal discharge detection method in a laser oscillator, characterized in that to detect the abnormal discharge in these two systems. 2. An oscillator control section drives a power supply section in response to a laser output command from a control device to apply a voltage between a pair of electrodes arranged in a vacuum vessel and discharge the laser light. The laser light is received by an optical sensor and sent to the oscillator control unit, and the laser control unit performs arithmetic processing on the laser light and inputs the laser output value to the control unit. A laser oscillator that is driven and controlled so that the output value substantially matches, when an abnormal discharge occurs in the vacuum container, discharges the charge to an abnormal discharge receiving member disposed in the vacuum container, A first abnormality in which the oscillator control unit notifies the oscillator control unit that the abnormal discharge receiving member has been discharged, and the oscillator control unit issues a command to stop voltage application to the power supply unit to stop abnormal discharge. When the laser output command value and the laser output value are different from each other by a predetermined value or more, the oscillator control unit issues a command to stop the voltage application to the power supply unit to perform abnormal discharge. A laser oscillator comprising: a second abnormal discharge detecting means for stopping the laser oscillator. 3. A vacuum vessel provided with a pair of electrodes opposed to each other and provided with a laser medium, and a power supply for exciting a laser medium by applying a voltage between the pair of electrodes to discharge the laser medium. Unit, an optical sensor that receives the emitted laser light, an amplifier that amplifies the laser light received by the optical sensor, and a drive control unit that controls the power supply unit, and performs an arithmetic process on the laser light that is amplified by the amplifier. An oscillator control unit that outputs a laser output value to the oscillator control unit, and a control device that receives the laser output value from the oscillator control unit; and an abnormal discharge occurs in the vacuum vessel. An abnormal discharge receiving member disposed in the vacuum vessel, which discharges the electric charge sometimes, and detecting that the electric charge has been discharged to the abnormal discharge receiving member. Abnormal discharge detection circuit, when abnormal discharge is detected by the abnormal discharge detection circuit, the oscillator control unit issues a command to stop voltage application to the power supply unit to stop abnormal discharge, When the laser output command value and the laser output value are different from each other by a predetermined value or more, the oscillator control unit issues a command to stop the voltage application to the power supply unit to stop the abnormal discharge. A laser oscillator characterized in that: 4. An oscillator control section drives a power supply section in response to a laser output command from a control device to apply a voltage between a pair of electrodes disposed in a vacuum vessel and discharge the laser light by applying a voltage to the vacuum vessel. The laser light is received by an optical sensor and sent to the oscillator control unit, and the laser control unit performs arithmetic processing on the laser light and inputs the laser output value to the control unit. A laser oscillator that is driven and controlled so that the output value substantially matches, and when an abnormal discharge occurs in the vacuum container, the charge is discharged to an abnormal discharge receiving member disposed in the vacuum container. Notifying the oscillator control unit that the abnormal discharge receiving member has been discharged, the oscillator control unit issues a command to stop voltage application to the power supply unit to stop the abnormal discharge. Detecting means, when the laser output command value and the laser output value are different from each other by a predetermined value or more, the oscillator control unit issues a command to stop voltage application to the power supply unit to stop abnormal discharge. And a second abnormal discharge detecting means for determining whether or not the first abnormal discharge detecting means and the second abnormal discharge detecting means have failed if any one of the first abnormal discharge detecting means and the second abnormal discharge detecting means operates. A failure determination method for abnormal discharge detection means in a laser oscillator, wherein both failure means are determined to be failed when both of them do not operate.