JP2002319724A - Gas laser oscillator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To automate leakage checking of a gas laser oscillator. SOLUTION: A turbo blower for circulating a laser gas is stopped, and a gas pressure control is stopped. Fault checking, confirming of a leakage check mode on, starting of performing of evacuation into vacuum and the like are conducted in a vacuum pump 6, and the sequence of the leakage checking is started in the pump 6. Old data on the display screen of a display unit is cleared (M1) and all valves which participate in the sealing of a space including a discharge tube are closed (M2). After the pump is stopped (M3), a set time is awaited for T2 sec. (M4), a first gas-pressure sampling is executed, output data of a gas pressure sensor is stored in the memory of a controller, and displayed on the screen (M5). Likewise, the setting time is thereafter awaited for T3 sec. (M6, M8, and M10), and a gas-pressure sampling (M7, M9, and M11) is conducted. If the gas pressure displayed on the screen is raised sequentially at respective times, the presence of leakage is detected.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas laser oscillator used in, for example, a laser processing apparatus, and more particularly, to a gas laser oscillator having a function of checking gas leak.

[0002]

2. Description of the Related Art In general, a gas laser oscillator used in a laser processing apparatus or the like includes a discharge tube for laser excitation of a laser gas, an exhaust means for exhausting a gas in a ventilation system including a space in the discharge tube, and an opening / closing ventilation system. It is provided with related valves, a control device for controlling a system including these valves, and the like. As this control device, a control device of a laser processing device including an NC control unit can be used.

In such a gas laser oscillator, there is a possibility that laser gas leaks due to a failure of a valve or a gas joint. The pressure inside the discharge tube of the gas laser oscillator is usually close to a vacuum except for the operation stop period after the purge. Therefore, if there is a gas leak, external air enters the discharge tube arranged in the optical resonator, and the operation of the laser oscillator becomes unstable.

In order to prevent this, a gas leak is checked in a manufacturing process or a laser processing site. Conventionally, this leak check is performed using the timing at the time of stopping the operation (laser oscillation) as described below. That is, when the operation (laser oscillation) is stopped, the gas inside the discharge tube is once exhausted, so that the gas pressure is reduced to almost 0
In general, a procedure is adopted in which the power supply is once turned off when the power supply reaches, and the power supply is turned on again after a predetermined time has elapsed to read the laser gas pressure and determine whether or not there is a leak.

However, in this method, it is necessary for the worker to measure the time, the worker must be on the site, and if the measurement of the time is erroneous, it is necessary to start over from exhausting the gas in the discharge tube. There was a problem that there is.

[0006]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the above-mentioned problems of the prior art and to provide a gas laser oscillator capable of performing a leak check without imposing a burden such as time measurement on an operator. is there.

[0007]

SUMMARY OF THE INVENTION The present invention provides an exhaust means for exhausting gas in a blower system in a gas laser oscillator, all valve closing means for closing all valves related to sealing of the blower system, In a gas laser oscillator comprising a gas pressure measuring means for measuring the laser gas pressure of the gas and a time measuring means for measuring the time, the gas in the air blowing system is exhausted to a predetermined pressure by the exhaust means, and the all valve closing means After closing all valves involved in sealing the ventilation system,
The above problem has been solved by recognizing the arrival of a timing after a predetermined time by a predetermined number of times by the timing unit and measuring the gas pressure by the gas pressure measurement unit each time the arrival of the timing is recognized. is there.

Here, it is preferable that the laser oscillator further comprises a display means having a display screen, so that the measured gas pressure can be displayed on the display screen. Further, a storage unit for storing the measurement result of the gas pressure is further provided,
It is further preferable that the measurement result can be read out from the storage means and displayed on the display screen.

As described above, according to the present invention, the presence / absence of leakage of the laser oscillator is automatically tested. That is, after evacuating the air supply system and closing all valves involved in automatically closing the air supply system, the gas pressure in the discharge tube is measured at regular intervals. The measurement results are stored and can be referred to on a display screen of a display attached to the control device, for example.

[0010]

FIG. 1 is a block diagram showing a main configuration of a laser oscillator according to one embodiment of the present invention. In the figure, reference numeral 1 denotes a discharge tube constituting a main body of a laser oscillator including an optical resonator, which is connected to a control device 10 via a drive circuit (not shown) to turn on / off discharge and discharge. Voltage control and the like are controlled. The laser output unit of the optical resonator is provided with a shutter (not shown) for optically blocking / passing a laser output beam, and the opening and closing of the shutter is performed by the control device 10.

The supply of the laser gas to the discharge tube 1 is performed from a cylinder 2 through a supply valve 3 and a gas pressure control valve 4.
The control of the supply valve 3 and the gas pressure control valve 4 is also performed by the controller 10 (connection lines are not shown). Reference numeral 8 denotes a sensor for detecting the gas pressure in the discharge tube 1, and its output is sent to the control device 10. As will be described later, at the time of a leak check, the output of the gas pressure sensor 8 is sampled by the control device 10 and stored, displayed, printed, and the like. The storage is performed using a memory built in the control device 10, and the display and printing are performed using a display 11 and a printer 12 attached or connected to the control device 10.

As is well known, the discharge tube 1 is provided with a gas circulation path that passes through the inside of the optical resonator (inside the optical resonance space) and the outside (outside of the optical resonance space) to prevent overheating of the laser gas. ing. Reference numeral 9 denotes a turbo blower for flowing gas along the gas circulation path, and its on / off is controlled by a control device 10. Further, heat exchangers 21 and 22 are provided on the suction side and the discharge side of the turbo blower 9 respectively.
Is provided.

Further, the discharge tube 1 is provided with an exhaust passage, which is connected to a vacuum pump 6 via an exhaust valve 7. The control device 10 also controls opening and closing of the exhaust valve 7 and on / off of the vacuum pump 6.
(Connection lines are not shown). When the exhaust valve 7 is opened and the vacuum pump 6 is turned on, the gas in the discharge tube 1 (including the circulation path) is exhausted to the outside, and so-called vacuuming is performed. In order to rapidly supply the laser gas to the inside of the discharge tube 1 (including the circulation path) and to bring the pressure to the atmospheric pressure, a bypass from the cylinder 2 to the discharge tube 1 through the purge valve 5 is used. The opening and closing of the purge valve 5 is also controlled by the control device 10 (connection lines are not shown).

As described above, the control device for controlling each part of the laser oscillator may be dedicated to the laser oscillator. However, in the case of a laser processing machine, the control device for performing NC control of the processing machine is also used. Can be done. In any case,
The control device includes a CPU, a memory, and an interface for input / output with each unit of the laser oscillator, has a function of executing a leak check-related process described below, and controlling the associated laser oscillator unit.

In the present embodiment, utilizing the above system configuration, a leak check-related process is executed when the operation of the laser oscillator is stopped. This processing is performed by setting necessary conditions for the control device 10 (setting of times T1 to T3 described later, etc.).
Is carried out automatically without bothering the operator. An outline of the leak check related processing is shown in the flowchart of FIG. FIG. 3 is a flowchart showing an outline of a leak check sequence included in the processing.

The main points of each step are as follows. The state of the laser oscillator at the start of the processing is such that the gas pressure is the gas pressure at the end of the operation (for example, 0.1 atm), and the shutter for optically blocking / passing the laser output beam is closed. is there. The discharge is naturally off.

Step S1: The turbo blower 9 is stopped,
Stop the gas pressure control.

Step S2: Check whether there is any abnormality in the vacuum pump 6. Usually, a vacuum pump is equipped with a temperature sensor for detecting an abnormality,
By monitoring at 0, the presence or absence of abnormality of the vacuum pump 6 is checked. Since the point in time when this step S2 is executed is immediately after the stop of the operation, if there is an abnormality in the vacuum pump 6, it is detected as a high temperature exceeding a predetermined value.

As a result of the check, if there is an abnormality in the vacuum pump 6, the leak check is abandoned, and the process is terminated through steps S11 and S12. In this case,
Naturally, after the processing is completed, an allowance (repair, replacement, etc.) for the abnormality of the vacuum pump 6 is required, but the detailed description is omitted because it is not particularly related to the present invention. If there is no abnormality in the vacuum pump 6, the process proceeds to step S3.

Step S3: Wait for a preset time T1 second (for example, 75 seconds).

Step S4: Check ON / OFF of the leak check mode. If it is on, the process proceeds to step S5, and if it is off, the process proceeds to step S6. A mode flag is set in the control device 10 for switching the leak check mode on / off. For example, a leak check mode on / off switch is provided in the control device 10, and when the operator presses (for example, presses) the switch, a mode flag is set and the leak check mode is turned on.

In this embodiment, however, it is assumed that once the operator activates the switch, the on state of the leak check mode is maintained even if the switch is subsequently deactivated (pulled back). Accordingly, even if the switch is accidentally deactivated after the switch is activated, the following steps need not be repeated.

Step S5: The necessity of evacuation is checked. A flag is set in the control device 10 to identify the necessity of evacuation. For example, the controller 10 is provided with a switch for switching the necessity of evacuation, and an operator operates the switch to determine whether or not evacuation is required. If evacuation is required, the process proceeds to step S7. If evacuation is not required, the process proceeds to step S11.

Step S6: Confirmation of setting of parameters T2 and T3 related to the leak check sequence (Step S10; see FIG. 3) is performed.

Step S7: The evacuation is started.

Step S8: The leak check mode is reconfirmed using the time required for evacuation. If the mode is the leak check mode, the process proceeds to step S10; otherwise, the process proceeds to step S9.

Step S9: The vacuum pump 6 is stopped.
The evacuation stop timing is a point in time when a predetermined time elapses after the evacuation starts.

Step S10: Enter a leak check sequence. The outline is shown in the flowchart of FIG. The main points of each of the steps M1 to M12 are as follows.

Step M1: Clear the display of old data (gas pressure sampling result, etc.) on the display screen (leak diagnosis screen) of the display device 11. Also, the memory area in which the data of the current leak check result (such as the gas pressure sampling result) is written is cleared. Thereby, for example, the columns displaying the first to fourth gas pressure measurement results are displayed in a blank state (no data display) on the display screen (leak diagnosis screen) of the display 11.

Step M2: all valves (supply valve 3, gas pressure control valve 4, purge valve 5, exhaust valve 7) involved in sealing the space including the discharge tube 1 and the gas circulation path are closed (already closed). Confirmation of the valve that is used).

Step M3: Confirm stoppage of the vacuum pump 6 (if not stopped, stop the vacuum pump 6).

Step M4: Wait for a preset time T2 seconds (for example, 30 seconds).

Step M5: The first gas pressure sampling is performed. The control device 10 stores the output of the gas pressure sensor 8 received via the interface in the memory, and displays the first gas pressure sampling result on the display 11.
(Pressure data is displayed in the corresponding column).

Step M6: Wait for a preset time T3 seconds (for example, 300 seconds).

Step M7: A second gas pressure sampling is performed. The control device 10 stores the output of the gas pressure sensor 8 received via the interface in the memory, and displays the result of the second gas pressure sampling on the display 11.
(Pressure data is displayed in the corresponding column).

Step M8: Wait for a preset time T3 seconds (for example, 300 seconds).

Step M9: A third gas pressure sampling is performed. The control device 10 stores the output of the gas pressure sensor 8 received via the interface in the memory, and displays the result of the third gas pressure sampling on the display 11.
(Pressure data is displayed in the corresponding column).

Step M10: Time T3 set in advance
Wait for second (for example, 300 seconds).

Step M11: A fourth gas pressure sampling is performed. The controller 10 stores the output of the gas pressure sensor 8 received via the interface in the memory, and displays the fourth gas pressure sampling result on the display 1.
1 (the pressure data is displayed in the corresponding column). In this step, the repetition of the standby for a predetermined time and the gas pressure sampling is ended. The number of repetitions of the standby / gas pressure sampling is a preset number.
In this example, four times are set.

Step M12: The end processing of the leak check sequence is performed. With this process, the end of the leak check sequence is stored in the memory of the control device 10 together with the time. The end of the sequence is displayed on the display screen (leak diagnosis screen) of the display 11 together with the time.

Step S11: The purge valve 5 is opened to supply the laser gas to the discharge tube 1. This supply is performed while the output of the gas pressure sensor 8 is checked by the control device 10 in a short cycle. When the inside of the discharge tube 1 reaches the atmospheric pressure, the purge valve 5 is closed and the supply of the laser gas is terminated.

Step S12: A leak check completion process is performed. This processing includes processing for confirming that the valves 3, 4, 5, and 7 are closed, confirming that the vacuum pump 6 has been stopped, and inverting the leak check mode flag (from on to off).

Thus, the leak check related processing is completed. While this process is being performed, the operator does not have to do any work and can leave the site. The result of the leak check can be confirmed on the display screen (leak diagnosis screen) of the display 11 after the processing is completed. If necessary, the past leak check data can be read out from the memory and displayed on the display screen (leak diagnosis screen) of the display device 11. Further, the data can be printed on the printer 12.

The determination as to whether or not there is a substantial leak is usually made based on a standard provided in advance for each system. Generally speaking, if the data of the gas pressure sampling result rises each time sampling is performed, there is a leak, otherwise, there is no leak.

[0045]

According to the present invention, the manufacture of a laser oscillator,
In maintenance and repair, the check of the gas leak of the resonator is automated, so that the work of the leak check is reliably performed, and the unstable operation of the oscillator due to the gas leak is prevented.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a main configuration of a laser oscillator according to an embodiment of the present invention.

FIG. 2 is a flowchart illustrating an outline of a leak check-related process executed in the embodiment of the present invention.

FIG. 3 is a flowchart illustrating an outline of a leak check sequence included in a leak check related process.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Discharge tube 2 Cylinder 3 Supply valve 4 Gas pressure control valve 5 Purge valve 6 Exhaust valve 7 Vacuum pump 8 Gas pressure sensor 9 Turbo blower 10 Control device 11 Display device 12 Printer 21, 22 Heat exchanger

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Motohiko Sato 3580 Kobaba, Oshino-mura, Oshino-mura, Minamitsuru-gun, Yamanashi F-Fan Co., Ltd. F-term (reference) 5F071 HH02 HH03 JJ05

Claims (3)

[Claims] An exhaust means for exhausting gas in a blowing system of a gas laser oscillator, all valve closing means for closing all valves related to sealing of the blowing system, and a gas pressure for measuring a laser gas pressure in the blowing system. In a gas laser oscillator including a measuring unit and a time measuring unit for measuring time, the exhausting unit exhausts gas in a blowing system to a predetermined pressure, and the entire valve closing unit seals the blowing system. After closing all the valves, the arrival of a timing after a predetermined time is recognized a predetermined number of times by the timing unit, and the gas pressure is measured by the gas pressure measurement unit every time the arrival of the timing is recognized. Gas laser oscillator. 2. A display device further comprising a display means having a display screen.
The gas laser oscillator according to claim 1, wherein the measured gas pressure is displayed on the display screen. 3. The gas laser oscillator according to claim 2, further comprising storage means for storing a measurement result of the gas pressure, wherein the measurement result is read from the storage means and displayed on the display screen.