JP2010212559A - Gas laser oscillator - Google Patents

Abstract

An object of the present invention is to provide a gas laser oscillation apparatus suitable for high output that suppresses discharge disturbance due to a laser gas composition change due to the intrusion of air and moisture into a gas circulation portion during a long-term stop or the invasion of laser gas into the atmosphere. Objective.
A cylinder 14 for supplying laser gas during startup, a vacuum pump 15 for exhausting laser gas, a control for controlling the amount of laser gas supplied from the cylinder 14 and the amount of laser gas exhausted by the vacuum pump 15 using laser gas. The controller 16 includes a vacuum pump 15 at the time of start-up, and after supplying the gas from the cylinder 14 to the vicinity of the atmospheric pressure, the controller 16 discharges the laser gas again with the vacuum pump 15 and then reaches the operating gas pressure from the cylinder 14. As a sequence for supplying air, the gas pressure discharged by the vacuum pump 15 at the time of startup is lower than the gas pressure at the time of startup and higher than the gas pressure discharged by the vacuum pump 15 again.
[Selection] Figure 1

Description

  The present invention relates to a gas laser oscillation device that exhausts and supplies laser gas at startup.

  Gas laser oscillators mounted on sheet metal processing apparatuses have been used for large purposes for high-speed cutting of thin plates, cutting of thick plates such as mild steel, aluminum, and stainless steel, and welding.

  FIG. 6 shows an example of an axial flow type gas laser device as an example of a schematic configuration of a general gas laser oscillation device. Hereinafter, the gas laser oscillation device will be described with reference to FIG.

  The gas laser oscillation device shown in the figure is provided with discharge tubes 31 and 41 made of a dielectric material such as glass, and electrodes 32, 33, 42, and 43 are provided at both ends of the respective discharge tubes 31 and 41.

  The electrodes 32 and 33 and the electrodes 42 and 43 are connected to high-voltage power sources 63 and 62 so as to apply a high voltage. The discharge tubes 31 and 41 have discharge spaces 34 and 44 (in the drawing). (Hatched portion) is formed.

  As described above, normally, there are a plurality of discharge tubes sandwiched between electrodes, and the discharge tubes 31 and 41 are arranged along the optical axis 91 of the laser beam represented by a one-dot chain line.

  Discharge spaces 34 and 44 are arranged on an optical axis 91 (represented by an alternate long and short dash line) so that the final mirror 5 that is substantially totally reflected and the output mirror 6 that is partially reflected so as to sandwich the discharge tubes 31 and 41. Are arranged at both ends to form an optical resonator.

  Usually, since a high voltage of several tens of kV is applied to the electrode section, the final stage mirror 5 and the output mirror 6 are provided with non-discharge tubes 51 and 61 made of a dielectric material such as glass between the electrodes 33 and 43. Insulation.

  Note that a laser gas is caused to flow in the directions of arrows 21 and 22 through the discharge tubes 31 and 41. Therefore, the supply pipe blocks 12 and 11 for distributing and sending the laser gas to the discharge tubes 31 and 41 are connected, and the exhaust pipe block 13 for collecting the laser gas flowing out from the discharge tubes 31 and 41 is connected.

  Thus, in order to circulate the laser gas through the discharge tubes 31 and 41, the circulation pump 7 is provided in the laser gas circulation path, and the heat exchanger 8 for cooling and circulation is provided in the laser gas circulation path.

  In this way, the laser gas is circulated through the air supply piping blocks 11 and 12 and the exhaust piping block 13 at a pressure of about 10 to 30 kPa.

  In addition, each component of said laser oscillation apparatus is connected via vacuum seal members, such as an O-ring, and has isolate | separated the laser gas circulation part and air | atmosphere.

  Further, in order to discharge the deteriorated laser gas and replace it with a new laser gas, a laser gas cylinder 14 for supplying the laser gas and a vacuum pump 15 for discharging the gas dissociated by the discharge are provided. A control unit 16 that controls the amount of laser gas from the pump 15 with an electromagnetic valve is provided to control the internal pressure of the discharge tubes 31 and 41.

  The above is the configuration of a general gas laser oscillation apparatus. Next, the operation will be described.

  The laser gas that has passed through the air supply piping blocks 11 and 12 is introduced into the discharge tubes 31 and 41. In this state, discharge energy is obtained from the electrodes 32, 33, 42, 43 and excited to generate discharge in the discharge spaces 34, 44. The laser gas in the discharge spaces 34 and 44 flows into the exhaust pipe block 13 to become a laser gas flow 23 and returns to the heat exchanger 8 and the circulation pump 7.

  At this time, there is no gas flow in the dischargeless tubes 51 and 61, no discharge is generated, and insulation between the discharge spaces 34 and 44, the final stage mirror 5 and the output mirror 6 is maintained.

  These excited laser gases are in a resonance state by an optical resonator formed by the output mirror 6 and the final stage mirror 5, and laser light 9 is output from the output mirror 6.

  Next, referring to FIG. 6, the laser gas startup sequence of the conventional laser oscillation apparatus will be described. When the gas laser oscillator is stopped, the laser gas is filled at about atmospheric pressure. When activated, the vacuum pump 15 operates, and the control unit 16 opens the electromagnetic valve connected to the vacuum pump 15 and discharges the laser gas to a pressure of about 0.5 to 2 kPa. Thereafter, the control unit 16 controls and supplies the electromagnetic valve connected to the cylinder 14 so that the operating gas pressure is 10 to 30 kPa from the cylinder 14. Thereafter, during normal operation, a constant amount of laser gas is discharged from the vacuum pump 15 while supplying a constant amount of laser gas from the cylinder 14, and the pressure in the discharge tubes 31 and 41 is maintained by the control unit 16.

In addition, in order to remove the moisture adsorbed on the inner wall of the gas circulation path during the stop period, heat is applied by discharging for a certain time after startup, and the laser gas consumption is increased by a factor of about 5 for a certain time. Some oscillate (see, for example, Patent Document 1).
JP-A-10-56221

  In such a conventional gas laser oscillating device, when the size of the device increases due to an increase in output or the like, the number of vacuum seals increases, so that the amount of air and moisture entering the gas circulation system increases.

  In addition, the amount of leaching of a partial component of the laser gas, particularly a gas having a low molecular weight such as helium gas, also occurs. This tendency increases especially when the suspension period is long, such as weekends and holidays, so the composition of the laser gas in the laser gas circulation part immediately after startup changes from the set value, discharge disturbance occurs, the laser output decreases, and in some cases the discharge When the high voltage is applied immediately after startup, the discharge voltage may not be discharged to the discharge tube but may be discharged to the non-discharge tube 51 or may be discharged to the housing through the atmosphere, that is, a ground fault may occur.

  Conventionally, in order to avoid such a situation, it has been necessary for the user of the processing machine to manually replace the laser gas while watching the situation at the time of start-up.

  Moreover, the thing shown in patent document 1 has little effect which suppresses discharge disturbance with respect to the change of the composition of the gas immediately after starting.

  In view of the above-described conventional problems, the present invention provides a large output that suppresses discharge disturbance due to laser gas composition change due to the intrusion of air and moisture into the gas circulation portion during long-term shutdown, and the intrusion of laser gas into the atmosphere. An object of the present invention is to provide a gas laser oscillation device suitable for the above.

  In order to achieve the above object, in the gas laser oscillation apparatus of the present invention, a laser gas is used to supply the laser gas during startup, a vacuum pump for exhausting the laser gas, a laser gas amount supplied from the cylinder, and A control unit for controlling the amount of laser gas exhausted by the vacuum pump; the control unit exhausts the laser gas by the vacuum pump at start-up, and then supplies the laser gas from the cylinder to near atmospheric pressure; As a sequence for supplying air from the cylinder to the operating gas pressure after exhausting with the pump, the gas pressure exhausted with the vacuum pump at the start is lower than the gas pressure at the start and the gas pressure exhausted with the vacuum pump again Is higher than

  With this configuration, it is possible to maintain the composition of the laser gas at the start-up while reducing the consumption of the laser gas and shortening the time.

  In addition, the stop period of the gas laser oscillation device is measured with a timer provided in the control unit, and when the stop time exceeds the set value, the conventional gas replacement at the start-up is replaced with another rough gas replacement. By adding, in addition to the effects of the above configuration, the amount of laser gas used can be reduced.

  As described above, these configurations always eliminate the change in the composition of the laser gas in the stopped gas circulation path even when starting after a long-term stop, and stabilize the discharge start voltage and the discharge state. Stable laser output can be obtained. Stable processing performance can be obtained.

  Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment)
FIG. 1 is a schematic configuration diagram of a gas laser oscillating device at the start-up of the present invention. The gas laser oscillating device shown in the figure is provided with discharge tubes 31 and 41 made of a dielectric material such as glass. Electrodes 32, 33, 42 and 43 are provided at both ends.

  The electrodes 32 and 33 and the electrodes 42 and 43 are connected to high-voltage power sources 63 and 62 so as to apply a high voltage. The discharge tubes 31 and 41 have discharge spaces 34 and 44 (in the drawing). (Hatched portion) is formed.

  As described above, normally, there are a plurality of discharge tubes sandwiched between electrodes, and the discharge tubes 31 and 41 are arranged along the optical axis 91 of the laser beam represented by a one-dot chain line.

  Discharge spaces 34 and 44 are arranged on an optical axis 91 (represented by an alternate long and short dash line) so that the final mirror 5 that is substantially totally reflected and the output mirror 6 that is partially reflected so as to sandwich the discharge tubes 31 and 41. Are arranged at both ends to form an optical resonator.

  Usually, since a high voltage of several tens of kV is applied to the electrode section, the final stage mirror 5 and the output mirror 6 are provided with non-discharge tubes 51 and 61 made of a dielectric material such as glass between the electrodes 33 and 43. Insulation.

  Note that a laser gas is caused to flow in the directions of arrows 21 and 22 through the discharge tubes 31 and 41. Therefore, the supply pipe blocks 12 and 11 for distributing and sending the laser gas to the discharge tubes 31 and 41 are connected, and the exhaust pipe block 13 for collecting the laser gas flowing out from the discharge tubes 31 and 41 is connected.

  Thus, in order to circulate the laser gas through the discharge tubes 31 and 41, the circulation pump 7 is provided in the laser gas circulation path, and the heat exchanger 8 for cooling and circulation is provided in the laser gas circulation path.

  In this way, the laser gas is circulated through the air supply piping blocks 11 and 12 and the exhaust piping block 13 at a pressure of about 10 to 30 kPa.

  In addition, each component of said laser oscillation apparatus is connected via vacuum seal members, such as an O-ring, and has isolate | separated the laser gas circulation part and air | atmosphere.

  Further, in order to discharge the deteriorated laser gas and replace it with a new laser gas, a laser gas cylinder 14 for supplying the laser gas and a vacuum pump 15 for discharging the gas dissociated by the discharge are provided. A control unit 16 that controls the amount of laser gas from the pump 15 with an electromagnetic valve is provided to control the internal pressure of the discharge tubes 31 and 41.

  The configuration so far is the same as the conventional one, but the feature of the present embodiment is that the controller 16 discharges the laser gas with the vacuum pump 15 at the start-up and supplies air from the cylinder 14 to the vicinity of the atmospheric pressure. After the laser gas is again discharged from the vacuum pump 15 by the vacuum pump 15, the gas pressure discharged from the vacuum pump 15 at the time of startup is lower than the gas pressure at the time of startup and again The point is that the pressure is higher than the gas pressure discharged by the vacuum pump 15.

  The control unit 16 can perform this sequence at every activation. However, if the activation is not performed after a long-term stop, the composition of the laser gas may be maintained without performing the above-described sequence.

  Therefore, in the present embodiment, the control unit 16 is provided with a timer 16a for measuring the stop time.

  Next, the operation will be described.

  FIG. 2 shows a chart at start-up in the present embodiment. When the activation signal is input to the control unit 16, the stop time measured by the timer 16a is compared with the set value. When the stop time is smaller than the set value, the start is performed according to the conventional start sequence shown in FIG. On the contrary, when the stop time is larger than the set value, the activation is performed according to the activation sequence shown in FIG.

  Next, the activation sequence shown in FIG. 3 will be described.

  When the gas laser oscillator is stopped, the laser gas is filled at about atmospheric pressure. When activated, the vacuum pump 15 is operated, the electromagnetic valve connected to the vacuum pump 15 is opened, the laser gas is discharged to a pressure of about 10 kPa, and then the electromagnetic valve connected to the vacuum pump 15 is closed and the electromagnetic valve connected to the cylinder 14 is Open and supply laser gas to atmospheric pressure. After that, the solenoid valve connected to the cylinder 14 is closed, the solenoid valve connected to the vacuum pump 15 is opened, the laser gas is discharged again to a pressure of about 0.5 to 2 kPa, and then the solenoid valve connected to the cylinder 14 is opened. Laser gas is supplied at an operating gas pressure of 10 to 30 kPa. Thereafter, during normal operation, both the solenoid valve connected to the cylinder 14 and the solenoid valve connected to the vacuum pump 15 are controlled by the control unit 16 so that the laser gas is supplied while the laser gas is discharged. The pressure is kept.

  Thus, as a sequence at the time of startup, the gas pressure discharged by the vacuum pump at the time of startup is set lower than the gas pressure at the time of startup and higher than the gas pressure discharged by the vacuum pump again, so that only twice. In both cases, it is possible to reduce the amount of laser gas consumed compared to discharging the laser gas to a pressure of about 0.5 to 2 kPa, and to shorten the time until startup.

  Although it is possible to set the gas pressure when discharging with the first vacuum pump to a lower value and set the gas pressure when discharging again with the vacuum pump to a higher value, it is not limited to the laser gas supply / discharge sequence. Since the sequence for starting the discharge is also included as a series of sequences, considering that the stop time is smaller than the set value, it is possible to set the sequence before the start of discharge to be the same. It is preferable from the viewpoint.

  FIG. 4 shows the effect of this embodiment.

  As shown in the figure, when the stop time increases, the laser output at the time of start-up decreases in the conventional gas laser oscillation device, but in this embodiment, the laser immediately after start-up is not affected by the stop time. The output can be kept.

  In addition, since there is no discharge turbulence in the conventional startup sequence after a single gas replacement when starting after a short-term stop, the conventional start-up sequence is used and startup after a long-term stop is performed without increasing the startup time or laser gas consumption. Sometimes the startup sequence described above is used, so that stable laser output can be easily obtained.

  The laser oscillator according to the present invention is useful as a gas laser oscillator capable of stabilizing the laser output and the laser mode.

Schematic configuration diagram of a gas laser oscillation device in an embodiment of the present invention Explanatory drawing of the starting sequence of the gas laser oscillation apparatus in embodiment of this invention Explanatory drawing of the starting sequence of the gas laser oscillation apparatus in embodiment of this invention Explanatory drawing which shows correlation of stop time and laser output in embodiment of this invention and the conventional gas laser oscillation apparatus Schematic configuration diagram of a conventional gas laser oscillator Explanatory diagram of startup sequence of conventional gas laser oscillator

14 cylinder 15 vacuum pump 16 control unit 16a timer

Claims (3)

A cylinder for supplying the laser gas during startup using a laser gas, a vacuum pump for exhausting the laser gas, a laser gas amount supplied from the cylinder, and a controller for controlling the amount of laser gas exhausted by the vacuum pump; The controller is configured to supply the laser gas from the cylinder to the operating gas pressure after exhausting the laser gas again from the cylinder after the vacuum pump is exhausted at the start-up and then supplying the laser gas to the vicinity of the atmospheric pressure. As a gas laser oscillation apparatus, the gas pressure discharged by the vacuum pump at the time of activation is lower than the gas pressure at the time of activation and higher than the gas pressure discharged by the vacuum pump again. A timer for observing the stop time is provided in the control unit, and only when the stop time is equal to or longer than a set time, the control unit discharges the laser gas with the vacuum pump at the start and then from the cylinder to the vicinity of atmospheric pressure. The gas laser oscillation apparatus according to claim 1, wherein after the supply of air, the laser gas is discharged again by the vacuum pump, and then supplied from the cylinder to an operating gas pressure. When the stop period is equal to or longer than a set time, the control unit discharges the laser gas with the vacuum pump at startup, and then supplies the laser gas from the cylinder to near atmospheric pressure, and then discharges the laser gas again with the vacuum pump. 3. A selection means for selecting whether to supply air from the cylinder up to an operating gas pressure or to supply air from the cylinder up to the operating gas pressure after the laser gas is discharged by the vacuum pump at the time of startup. Gas laser oscillation device.

Images