KR20060134165A - Gas laser oscillator and gas laser material processing machine - Google Patents

Abstract

Laser gas pressure in a housing (7) is detected by means of a gas pressure sensor (12) and then a pressure comparison circuit (13) makes a decision as to whether it is normal or not. Output current from an inverter (10) for driving a blower (5) refluxing the laser gas is detected by means of a current detection circuit (9) and then a current comparison circuit (11) makes a decision as to whether it is normal or not. Results from the pressure comparison circuit (13) and the current comparison circuit (11) are fed to an AND circuit (15) and ANDed. Results from the AND circuit (15), the current detection circuit (9) and the gas pressure sensor (12) are fed to the comparing/operating section (17) in a controller (14) where a decision is made as to whether the blower is abnormal or not. If the blower is abnormal, a signal is delivered to an oscillator and a processing machine control section (18) to stop the operation of the oscillator and a processing machine. Consequently, abnormality of the blower (5) can be detected regardless of a variation in laser gas pressure.

Description

GAS LASER OSCILLATOR AND GAS LASER MATERIAL PROCESSING MACHINE}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas laser oscillator using a blower and a gas laser processor equipped with the gas laser oscillator.

In general, a gas laser oscillator has a pair of electrodes in a sealed housing, forcibly circulating laser gas enclosed in the housing by a blower. The laser gas is excited by the discharge generated by the pair of electrodes, and is irradiated to the outside by resonating by the partial reflection mirror and the total reflection mirror. And it sends to a processing head through several mirrors, and processes the workpiece | work on a processing table.

By the way, the blower which circulates a laser gas in such a laser oscillator is handled as a kind of consumable. If the blower stops for any reason during laser oscillation, the laser gas circulation stops and damages the optical component and the electrode in the housing. Moreover, when used for laser processing, by damaging the optical component and electrode in a laser oscillator, processing will continue, with the quality of a laser beam being abnormal, and the extensive influence which leads to processing defect will arise extensively. Throw it away. In the conventional blower maintenance management, the blower deterioration state is judged by the blower life expectancy generally estimated from the use of a laser oscillator during regular inspection. In addition, as a means of knowing the abnormality of the conventional blower, the abnormality can be solved from the relationship between the current value and the inertia rotation time of the inertia-rotating blower when the laser oscillator disclosed in Japanese Patent Laid-Open No. 1-106487 is stopped. A method of detecting or a method of detecting an abnormality is known by comparing the output current of the inverter section for supplying power to the blower disclosed in Japanese Patent Application Laid-Open No. 2003-110172 with a predetermined value.

The determination of blower deterioration by the conventional life expectancy has a drawback that the early blower replacement is inevitable from the preventive maintenance phase, and cannot be found except at regular inspections. In addition, the abnormal detection means of the conventional blower disclosed in Japanese Patent Laid-Open No. 1-106487 can detect abnormality only when the blower stops, and it is difficult to prevent abnormal stop during the use of the oscillator or the processing machine. On the other hand, with the conventional abnormality detection method of the blower disclosed in Japanese 2003-110172, it is possible to prevent abnormal stop during processing, but in general, the current value of the blower is not only deteriorated by the blower but also by the laser gas pressure in the housing. Since it deteriorates, there exists a fault which judges that the pressure change of a laser gas is deterioration of a blower.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object thereof is to provide a gas laser oscillator and a gas laser having a device capable of detecting a deterioration of a blower during the use of an oscillator or a processor regardless of the pressure deterioration of the laser gas. To get a processor.

In the gas laser oscillator and the gas laser processing machine which concern on this invention, it is equipped with the current detection means which detects the output current value of the inverter which supplies a drive electric power to a blower, and the pressure detection means which detects the pressure of the laser gas in an optical body, The abnormality of the blower is detected by using the output current value of the inverter detected by the current detecting means and the laser gas pressure value detected by the pressure detecting means.

With the above configuration, the present invention can detect the deterioration of the blower during the use of the oscillator or the processing machine regardless of the pressure change of the laser gas. Thereby, in a laser oscillator, the blower abnormal stop in laser oscillation can be prevented beforehand, and the effect that the damage of the optical component and electrode in the optical body accompanying a blower abnormal stop can be greatly reduced is acquired. Moreover, in the laser processing machine, the blower abnormal stop during laser processing can be prevented beforehand, and the effect that processing defects exerted extensively with the conventional blower abnormal stop can be suppressed only in the part in which the machine stopped.

1 is a side view of a laser oscillator showing Embodiment 1 of the present invention.

2 is a configuration diagram for detecting the front view and blower deterioration of the laser oscillator according to Embodiment 1 of the present invention.

3 is an example of a graph showing the relationship between the laser gas pressure and the blower current.

4 is a flowchart showing the operation of Embodiment 1 of the present invention.

5 is a configuration diagram for detecting the front view and blower deterioration of the laser oscillator according to the second embodiment of the present invention.

6 is a flowchart showing the operation of Embodiment 2 of the present invention.

7 is a configuration diagram for detecting the front view and blower deterioration of the laser oscillator in the third and fourth embodiments.

8 is a flowchart showing the operation of Embodiment 3 of the present invention.

9 is a flowchart showing the operation of Embodiment 4 of the present invention.

Best Mode for Carrying Out the Invention

Embodiment 1.

FIG. 1 is a schematic diagram showing a cross section of a laser oscillator in Embodiment 1 for carrying out the present invention, and FIG. 2 is a schematic diagram of a laser processing machine showing a longitudinal section of the laser oscillator and an apparatus for detecting an abnormal blower and a main body portion of a machine.

FIG. 1, in a second FIG housing 7 in the can is filled with a laser gas such as C0 _2, N _2, He. This laser gas is forcedly circulated in the direction of the arrow 6 by the plurality of blowers 5 arranged in the housing 7. After passing through the discharge space 2 between the pair of electrodes 1, the laser gas, which has become a high temperature, passes through the gas duct 3 and is cooled by the heat exchanger 4. The cooled laser gas is again refluxed between the electrodes 1 by the plurality of blowers 5. The laser gas circulated by the discharge generated by the pair of electrodes 1 is excited, and is resonated by the partial reflection mirror 20 and the total reflection mirror 16 and irradiated to the outside. And it sends to the processing head 24 in the machine main body 21 through the some mirror 26, irradiates the workpiece | work 23 on the processing table 25, and performs a process. The operation of the laser oscillator and the laser processing machine is controlled by the oscillator and the processor control unit 18 in the control device 14.

The pressure of the laser gas enclosed in the housing 7 varies depending on the model, but in general, the set value is set between about 50 Torr and about 200 Torr, and the difference from the set value is kept within the range of about ± 2 Torr. It is becoming. At the time of laser gas exchange, the pressure in the housing 7 is reduced to around 0.1 Torr. The laser gas pressure in the housing 7 is monitored by the gas pressure sensor 12 which is a laser gas pressure detecting means. And the output of the gas pressure sensor 12 is compared with the normal laser gas pressure by the pressure comparison circuit 13 which is a laser gas pressure comparison means, and it is determined whether the laser gas pressure is normal or abnormal.

On the other hand, the drive part of the blower 5 is comprised by the inverter 10 which supplies electric power, the current detection circuit 9 which is a blower current detection means, and the thermal relay 8. If a large current flows to the blower 5 by burning or the like, the thermal relay 8 moves to stop the laser oscillator. In addition, the output current of the inverter 10 is detected by the current detection circuit 9, and the current comparison circuit 11 which is a blower current comparison means determines whether the current value is normal or abnormal compared with the normal current value.

Since the blower 5 is rotating at a high speed in a vacuum state of about 50 to 200 Torr as described above, a method of reducing friction is adopted by applying a vacuum grease having a high vapor pressure to the bearing mechanism. However, even in this manner, wear of the bearing mechanism is often caused. Wear of the bearing mechanism increases the current required for rotation of the blower.

On the other hand, fluctuations in the blower current are also caused by fluctuations in the laser gas pressure as described above. Here, FIG. 3 shows a relationship between the blower current value and the laser gas pressure. Although FIG. 3 is a value in the laser oscillator used by the inventor for examination of the present invention, in general, when the laser gas pressure increases, the blower current also increases, and when the laser gas pressure decreases, the relationship that the blower current also decreases is established.

Therefore, in order to identify the factor which a blower current fluctuates more than a blower, it set as the following structures. The result output of the pressure comparison circuit 13 and the result output of the current comparison circuit 11 are sent to the AND circuit 15 to perform AND processing. The result of the AND circuit 15 and the output of the current detection circuit 9 and the output of the gas pressure sensor 12 are sent to the comparison operation unit 17 in the control unit 14 to determine whether or not the blower is abnormal in the comparison operation unit 17. If it is determined that the error is abnormal, a signal is sent to the oscillator and the machine control unit 18 to stop the oscillator and the machine, and a signal is also sent to the alarm device 19 to inform the operator of the error.

Next, the operation of the oscillator and the laser processing machine in the first embodiment will be described using the flowchart of FIG. 4 with reference to FIG. Here, the set gas pressure 55 ± 2 Torr of the laser oscillator in which the inventor considered the invention, the relationship between the laser gas pressure and the blower current shown in FIG. 3, and the set blower current 3.1 ± 0.1 corresponding to the set gas pressure obtained from FIG. Use A as an example. Of course, the relationship between the set gas pressure, the set blower current, the laser gas pressure, and the blower current may be appropriately determined by the oscillator to be applied, and is not particularly limited to the above values.

First, the blower current Id is detected by the current detection circuit 9, and the detected value is output to the blower current comparison circuit 11 and the comparison calculation unit 17 (step S01).

Next, the laser gas pressure Pd in the housing 7 is detected by the gas pressure sensor 12, and the detected value is output to the pressure comparison circuit 13 and the comparison calculation unit 17 (step S02).

Next, in the current comparison circuit 11, the set blower current Is (3.1 ± 0.1 A) stored in the current comparison circuit 11 is compared with the blower current value Id, and the current value Id is the set blower current value. Outputs a high signal (hereinafter referred to as H) if it is within the range of 3.1 ± 0.1 A, and outputs a low signal (hereinafter referred to as L) to the AND circuit (15) if the current value (Id) is not within the range of the set blower current value of 3.1 ± 0.1 A. (Step S03).

Next, the pressure comparison circuit 13 compares the set gas pressure Ps (55 ± 2 Torr) stored in the pressure comparison circuit 13 with the laser gas pressure Pd, and the gas pressure Pd is set to 55 ± 2 Torr. The high signal (hereinafter referred to as "H") is outputted when it is in the range of, and the low signal (hereinafter referred to as "L") is outputted when the gas pressure (Pd) is not in the range of 55 ± 2 Torr of set gas pressure (step S04).

Next, the AND circuit 15 performs an AND process on the output of the current comparison circuit 11 and the output of the pressure comparison circuit 13, and outputs the result to the comparison operation unit 17 (step S05).

If the result of the AND processing in Step S05 is High (hereinafter referred to as H), the blower 5 determines that it is normal and continues monitoring of the blower abnormality again from Step S01. In the case where the result of the AND processing in Step S05 is Low (hereinafter L), the possibility of blower abnormality is considered, and the following processing is performed.

In the comparison operation unit 17, the ideal blower current value Ic corresponding to the gas pressure Pd detected in step S02 is obtained by using the relationship between the blower current value stored in the comparison operation unit 17 and the laser gas pressure (FIG. 3). It calculates (step S06).

When the blower current value Id detected in step S01 falls within the range of Ic ± 0.1 A, the comparison calculation unit 17 determines that the blower 5 is normal, and continues to monitor the blower abnormality from step S01 again. If the blower current value Id does not fall within the range of Ic ± 0.1 A, the blower 5 determines that it is abnormal and sends a stop signal to the oscillator and the processing control unit 18, and also sends a signal to the alarm device 19 ( Step S07).

The oscillator and the machine control device 18 stop the oscillator and the machine, and the alarm device 19 alerts the operator (step S08).

The blower 5 is replaced by the operator who has received the warning (step S09).

In the first embodiment, by implementing the operation having the above-described configuration, by using the output current value of the inverter for driving the blower and the output of the gas pressure sensor, the factor of the gas pressure, which is a variation factor of the blower current, is eliminated and the blower is abnormal. The laser oscillator can be surely detected. Thereby, the effect which can greatly reduce that a blower stops during laser oscillation and damages the optical component and electrode in an optical body is acquired. Moreover, in the laser processing machine using this oscillator, the effect which can suppress processing defect to the minimum is acquired.

In addition, the inverter is usually equipped with a current detection function, and an alarm is sent when the blower current drops below a certain value. On the other hand, the blower current detection circuit detects the output current from the inverter and sends an alarm if it is not a current value suitable for gas pressure. In this way, by detecting the blower current at two places, the interlock is doubled.

Further, the blower current detection circuit need not be provided as many as the number of blowers, and one current detection circuit may be provided if a set value suitable for the number of blowers is set.

Embodiment 2.

By the way, in Embodiment 1, abnormality detection of the laser gas pressure and abnormality detection of a blower were performed in separate operation, but you may implement in the same operation | movement. As a structure, as shown in FIG. 5, the path | route which sends a stop signal from the pressure comparison circuit 13 to the oscillator and the processor control part 18 is provided about FIG. 2 which is a block diagram of Embodiment 1. As shown in FIG. The operation will be described using the flowchart of FIG.

Basically, it was almost the same as 4th degree, The difference was changed step S04 to new step S14, and step S10 and step S11 were newly added. Steps S14, S10, and S11 will be described below.

After the blower current is compared in step S03, the pressure comparison circuit 13 compares the set gas pressure Ps (55 ± 2 Torr) and the laser gas pressure Pd stored in the pressure comparison circuit 13, and compares the gas pressure. If (Pd) is within the range of 55 ± 2 Torr of set gas pressure, High signal (hereinafter H) is output.If gas pressure (Pd) is not within the range of 55 ± 2 Torr of gas pressure, it is judged that it is over gas pressure. A stop signal is sent to the control unit 18, and a signal is also sent to the alarm device 19 (step S14).

The oscillator and the processor control unit 18 stop the oscillator and the processor, and the alarm device 19 alerts the operator (step S10).

The operator 14 who received the warning exchanges the laser gas (step S11).

The second embodiment has the configuration described above and realizes the operation, thereby obtaining the same effects as those of the first embodiment, and also detecting abnormality in gas pressure during the abnormality detection process of the blower, even when the gas pressure is abnormal. The oscillator and the processing machine can be stopped immediately, and the damage of the optical component or the electrode in the oscillator body can be greatly reduced, and the processing defect can be minimized during the laser processing.

Embodiment 3.

FIG. 7 is a schematic diagram of a laser processing machine showing an apparatus for detecting a longitudinal cross section and a blower abnormality of a laser oscillator according to Embodiment 3 for carrying out the present invention, and a main body portion of a processing machine.

As shown in FIG. 7, the third embodiment eliminates the current comparison circuit 11, the pressure comparison circuit 13, and the AND circuit 15 from the first embodiment, and detects the gas detection pressure and the gas pressure of the current detection circuit 9. It is a structure which sends the detected value of the sensor 12 to the comparison calculating part 17, and determines the abnormality of a blower.

Next, the operation of the laser oscillator and the laser processing machine in the third embodiment will be described using the flowchart of FIG. 8 with reference to FIG. Here, as in Embodiment 1, the inventors correspond to the set gas pressure 55 ± 2 Torr of the laser oscillator in which the present invention has been studied, the relationship between the laser gas pressure and blower current shown in FIG. 3, and the set gas pressure obtained from FIG. Set blower current 3.1 ± 0.1 A as an example. Of course, what is necessary is just to determine suitably the relationship formula of a setting gas pressure, a laser gas pressure, and a blower current, and a setting blower current by the oscillator to apply, and are not specifically limited to the said value.

First, the blower current Id is detected by the current detection circuit 9, and the detected value is output to the comparison calculating section 17 (step S21).

Next, the gas pressure sensor 12 detects the laser gas pressure Pd in the housing 7 and outputs the detected value to the comparison calculation unit 17 (step S22).

In the comparison operation unit 17, the ideal blower current value Ic corresponding to the gas pressure Pd detected in step 2 is calculated using the relationship between the blower current value stored in the comparison operation unit 17 and the laser gas pressure (FIG. 3). (Step S23).

If the blower current value Id detected in step S21 falls within the range of Ic ± 0.1 A, the comparison calculation unit 17 determines that the blower 5 is normal, and continues to monitor the blower abnormality from step S21 again. If the blower current value Id does not fall within the range of Ic ± 0.1 A, the blower 5 determines that it is abnormal and sends a stop signal to the oscillator and the processor control unit 18, and also sends a signal to the alarm device 19 ( Step S24).

The oscillator and the processor control unit 18 stop the oscillator and the processor, and the alarm device 19 alerts the operator (step S25).

The blower 5 is replaced by the operator who received the warning (step S26).

The third embodiment has the above configuration and realizes the operation, thereby obtaining the same effect as the first embodiment and attaining the advantage that the circuit configuration is simpler than the first embodiment.

Embodiment 4.

By the way, in Embodiment 3, although the abnormality of the blower was detected by comparing the detected blower current value Id and the calculated blower current value Ic, even if the abnormality of a blower is detected by comparing the detected gas pressure Pd and the calculated gas pressure Pc. do. The configuration is the same as in the seventh degree. The operation will be described using the flowchart of FIG.

It is basically the same as the eighth degree, except that the steps S23 and S24 are replaced with the new steps S33 and S34. Hereinafter, steps S33 and S34 will be described.

In the comparison operation unit 17, the ideal gas pressure Pc corresponding to the blower current value Id detected in step S21 is calculated using the relationship between the blower current value stored in the comparison operation unit 17 and the laser gas pressure (FIG. 3). (Step S33).

When the gas pressure Pd detected in step S22 is within the range of Pc ± 2 Torr, the comparison calculation unit 17 determines that the blower 5 is normal, and continues monitoring the blower abnormality from step S21 again. If the gas pressure Pd does not fall within the range of Pc ± 2 Torr, the blower 5 determines that it is abnormal and sends a stop signal to the oscillator and the processor control unit 18, and also sends a signal to the alarm device 19 (step). S34).

The fourth embodiment has the above-described configuration and realizes the operation, thereby obtaining the same effect as the first embodiment, and attaining the advantage that the circuit configuration is simpler than the first embodiment.

As mentioned above, the gas laser oscillator and gas laser processing machine which concern on this invention are especially suitable for being used for the gas laser oscillator and gas laser processing machine which oscillate or process by operating a blower continuously for a long time.

Claims (5)

With an enclosed ore, A laser gas enclosed in the housing, A pair of electrodes for generating a discharge in said laser gas, A gas laser oscillator provided with a blower for flowing the laser gas between the electrodes, Current detecting means for detecting an output current value of an inverter for supplying driving power to the blower; Pressure detecting means for detecting a pressure of the laser gas in the housing; And an abnormality of the blower is detected using an output current value of the inverter detected by the current detecting means and a laser gas pressure value detected by the pressure detecting means. The method of claim 1, The relationship between the output current value of the inverter and the pressure value of the laser gas is stored, an ideal output current value is calculated from the laser gas pressure value detected by the pressure detecting means and the relationship expression, and the ideal output current value and the current detection means are detected. And a control device for controlling the gas laser oscillator to stop when it is determined that the blower is abnormal by comparing the actual output current value. The method of claim 2, Current comparison means for comparing the output current value and the set output voltage value of the inverter; Pressure comparison means for comparing the laser gas pressure value and the set gas pressure value detected by the pressure detection means; And an AND circuit for ANDing the results of each of the current comparing means and the pressure comparing means, And in the AND circuit, when it is determined that one of the results of each of the current comparing means and the pressure comparing means is out of a set value, the control device determines a blower abnormality. The method of claim 1, The relationship between the output current value of the inverter and the pressure value of the laser gas is stored, and an ideal laser gas pressure value is calculated from the output current value of the inverter detected by the current detection means and the relationship equation, and the ideal laser gas pressure value and the pressure are calculated. A gas laser oscillator, comprising a control device for controlling the gas laser oscillator to stop when it is determined that the blower is abnormal by comparing the actual laser gas pressure value detected by the detection means. With an enclosed ore, A laser gas enclosed in the housing, A pair of electrodes for generating a discharge in said laser gas, A gas laser processing machine for processing by a gas laser oscillator provided with a blower for flowing the laser gas between the electrodes, The gas laser oscillator is a gas laser oscillator according to any one of claims 1 to 4.

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