JP2006281308A - Laser apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laser apparatus capable of maintaining an excellent beam atmosphere in a beam guide at a low cost. <P>SOLUTION: The laser apparatus (100) comprises a laser beam oscillator (2), a condensing optical system (13) to condense laser beams output from the laser beam oscillator, a beam guide (30) to lead the laser beams from the laser beam oscillator to the condensing optical system, a dehumidifying means (40) to dehumidify air, and feed means (31, 32) to feed air dehumidified by the dehumidifying means to the beam guide. The atmospheric dew point of the air dehumidified by the dehumidifying means (40) is ≤0°C. When the distance (L) between the laser beam oscillator (2) and the condensing optical system (13) is larger than the predetermined value, a plurality of dehumidifying means (40a, 40b) are preferably included. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a laser device including a laser oscillator that excites a gas medium to obtain a laser output, or a laser processing machine that performs laser processing such as laser cutting and laser welding by laser output from such a laser oscillator.

  Generally used laser devices include a laser oscillator that outputs a laser and a condenser lens that condenses the output laser. The output laser is condensed on the work by the condensing lens, whereby the work is subjected to laser cutting or laser welding. In such a laser device, the light guide is disposed so as to connect the laser oscillator and the condenser lens, and the laser output from the laser oscillator propagates through the light guide and reaches the condenser lens.

  Usually air is present in the light guide. In such a case, the laser beam is absorbed and scattered on the basis of carbon dioxide in the air, that is, carbon dioxide, water vapor, and / or organic gas, and a propagation change of the laser beam occurs. Accordingly, the laser beam diameter of the laser expands according to the propagation distance. Thereby, the interference of the laser beam in the light guide is increased, and the quality of the laser beam is lowered. In such a case, the power of the laser beam focused on the workpiece by the condenser lens also decreases, so that the workpiece often becomes defective in processing.

  Nitrogen gas is supplied into the light guide path in order to prevent the workpiece from becoming defective due to the laser power reduction. Moreover, in patent document 1, the air which reduced the carbon dioxide gas density | concentration in air to the predetermined | prescribed density | concentration is supplied in the light guide using the carbon dioxide gas concentration reduction apparatus provided with the molecular filter.

When nitrogen gas is supplied to the light guide, the air in the light guide is replaced by nitrogen gas, so that carbon dioxide, water vapor, and / or organic gas, etc. that cause absorption and scattering of the laser beam are present in the light guide. Disappear. On the other hand, even in the case of Patent Document 1, since the air in the light guide is replaced with air having a low carbon dioxide concentration, the amount of carbon dioxide that causes absorption and scattering of the laser beam is reduced. Therefore, in these cases, there is little or no change in the propagation of the laser beam. As a result, the power of the laser focused on the workpiece is also maintained, so that the workpiece can be processed well. It becomes.
JP-A-9-99287

  However, when nitrogen gas is supplied to the light guide path, it is necessary to continue supplying nitrogen when the laser apparatus is used, so that there is a problem that the running cost becomes extremely expensive. In the case of Patent Document 1, although the running cost can be suppressed by the amount of not using nitrogen gas, a considerable cost is required for installing a carbon dioxide concentration reducing device equipped with a molecular filter. Moreover, this carbon dioxide concentration reducing device needs to be energized all the time even when the laser device is not used. For this reason, the overall cost required in the case of Patent Document 1 is not so much less than when nitrogen gas is supplied to the light guide.

  In particular, in recent years, there is a tendency for the light guide path to become longer for the purpose of increasing the dimensions of the workpiece, increasing the demand for three-dimensional processing machines having a complicated structure of the light guide path, and improving the quality of the laser beam. There is also a tendency to increase the possibility of absorption and scattering of the beam. Therefore, it is desired to maintain a good beam atmosphere in the light guide so that such absorption and scattering of the laser beam does not occur.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a laser apparatus that can favorably maintain the beam atmosphere in the light guide path at low cost.

  In order to achieve the above-described object, according to a first invention, a laser oscillator, a condensing optical system for condensing a laser output from the laser oscillator, for example, a condensing lens, and the laser from the laser oscillator There is provided a laser device comprising: a light guide that guides the light to the light collecting optical system; and a dehumidifying means that dehumidifies the air in the light guide.

  According to the second aspect of the invention, a laser oscillator, a condensing optical system that condenses the laser output from the laser oscillator, for example, a condensing lens, and the laser from the laser oscillator is guided to the condensing optical system. There is provided a laser apparatus comprising a light guide path, a dehumidifying means for dehumidifying air, and a supply means for supplying dehumidified air dehumidified by the dehumidifying means to the light guide path.

  That is, in the first and second inventions, since the air in the light guide path is dehumidified, the water vapor concentration in the air is reduced. For this reason, the absorption / scattering action of the laser beam based on the presence of water vapor is reduced, so that the propagation change of the laser beam does not occur. Therefore, the quality of the laser beam does not deteriorate, and it is possible to prevent the workpiece from being defective in processing. Since the dehumidifying means itself is inexpensive and does not need to be energized all the time, in the first and second inventions, it is possible to maintain the beam atmosphere in the light guide well at a low cost.

According to the third invention, in the first or second invention, when the distance between the laser oscillator and the condensing optical system is larger than a predetermined value, a plurality of dehumidifying means are included. did.
That is, in the third invention, when the length of the light guide corresponding to the distance between the laser oscillator and the condensing optical system is larger than a predetermined length, for example, 10 m, a plurality of dehumidifying means and / or A plurality of supply means can supply a sufficient amount of dehumidified air to the light guide path so that the propagation change of the laser beam does not occur. For example, when the length of the light guide is longer than 10 m, it is preferable to supply dehumidified air 60 times or more the total light guide volume to the light guide.

According to the fourth invention, in any one of the first to third inventions, the atmospheric pressure dew point of the dehumidified air dehumidified by the dehumidifying means is 0 ° C. or less.
When the dew point of dehumidified air, that is, the temperature at which the water vapor contained in the air is cooled to form water droplets at atmospheric pressure is greater than 0 ° C., the absorption and scattering of the laser beam increases, and a good laser beam It is known that propagation cannot be maintained. Accordingly, in the fourth aspect of the invention, the atmospheric pressure dew point of the dehumidified air is set to 0 ° C. or less, so that the beam atmosphere in the light guide is well maintained. Therefore, it is particularly advantageous to use the laser device of the present invention in a hot and humid area.

According to a fifth invention, in any one of the second to fourth inventions, the apparatus further comprises switching means provided in the supply means, and an air source connected to the switching means. The carbon dioxide concentration in the air is reduced to a predetermined carbon dioxide concentration, and the switching means passes either the dehumidified air from the dehumidifying means or the air from the air source through the supply means. The light guide was supplied.
When air having a low carbon dioxide gas concentration is supplied to the light guide, it is possible to suppress the propagation change of the laser beam compared to the case where dehumidified air is supplied to the light guide. Accordingly, in the fifth aspect of the present invention, when the dehumidified air alone is not sufficient to eliminate the propagation change of the laser beam in the light guide, the laser beam is supplied by using the switching valve to supply the low carbon dioxide concentration air. It is possible to suppress the occurrence of change in propagation of the workpiece and prevent the workpiece from being defective. Therefore, it is possible to reduce the running cost of the laser device as compared with the case where only air with a low carbon dioxide gas concentration is used.

According to a sixth invention, in any one of the second to fourth inventions, the switching means provided in the supply means, and a nitrogen source connected to the switching means, the switching means, Either dehumidified air from the dehumidifying means or nitrogen from the nitrogen source is supplied to the light guide through the supply means.
When nitrogen gas is supplied to the light guide, it is possible to suppress the propagation change of the laser beam compared to the case where dehumidified air is supplied to the light guide. Accordingly, in the sixth aspect of the invention, when the dehumidified air alone is not sufficient to eliminate the propagation change of the laser beam in the light guide, nitrogen gas is supplied to the light guide using the switching valve, thereby The occurrence of changes in propagation can be suppressed, and the workpiece can be prevented from becoming defective. Therefore, it is possible to reduce the running cost of the laser device as compared with the case where only nitrogen gas is used.

According to a seventh invention, in any one of the second to fourth inventions, it comprises switching means provided in the supply means, and an air source connected to the switching means, and the air in the air source The carbon dioxide gas concentration is reduced to a predetermined carbon dioxide gas concentration, further comprising a nitrogen source connected to the switching means, wherein the switching means includes dehumidified air from the dehumidifying means and air from the air source. Alternatively, any nitrogen from the nitrogen source is supplied to the light guide through the supply means.
When air or nitrogen gas having a low carbon dioxide gas concentration is supplied to the light guide, it is possible to suppress the occurrence of changes in the propagation of the laser beam, compared to when dehumidified air is supplied to the light guide. Therefore, in the seventh aspect, when the dehumidified air alone is not sufficient to eliminate the propagation change of the laser beam in the light guide, air or nitrogen gas having a low carbon dioxide concentration is supplied to the light guide using the switching valve. By doing so, it is possible to suppress the change in propagation of the laser beam and prevent the workpiece from being defectively processed. Therefore, the running cost of the laser device can be reduced as compared with the case where only air and / or nitrogen gas having a low carbon dioxide concentration is used. If the generation of laser beam propagation changes cannot be suppressed by supplying dehumidified air, low CO2 concentration air is supplied to the light guide. It is preferable to supply nitrogen gas to the light guide when it is not possible to suppress the occurrence of this.

According to the eighth invention, in any one of the fifth to seventh inventions, the switching action of the switching means is determined according to the distance between the laser oscillator and the condensing optical system.
According to a ninth invention, in any one of the fifth to seventh inventions, the laser beam condensed by the condensing optical system processes a workpiece, and the switching action of the switching means. Was determined according to the dimensions of the workpiece.
That is, in the eighth and ninth inventions, it is possible to efficiently select whether to use dehumidified air, air with a low carbon dioxide concentration, or nitrogen gas with a relatively simple configuration.

  According to each invention, the common effect that the beam atmosphere in the light guide path can be satisfactorily maintained at low cost can be obtained.

Further, according to the third aspect of the invention, it is possible to provide an effect that a sufficient amount of dehumidified air can be supplied to the light guide path so that the propagation change of the laser beam does not occur.
Furthermore, according to the fourth aspect of the invention, by setting the atmospheric pressure dew point of the dehumidified air to 0 ° C. or less, an effect of maintaining a good beam atmosphere in the light guide path can be achieved.
Furthermore, according to the fifth aspect, the running cost of the laser device can be reduced as compared with the case where only air with a low carbon dioxide gas concentration is used.
Furthermore, according to the sixth aspect, the running cost of the laser device can be reduced as compared with the case where only nitrogen gas is used.
Furthermore, according to the seventh aspect, the running cost of the laser device can be reduced as compared with the case where only air and / or nitrogen gas having a low carbon dioxide concentration is used.
Furthermore, according to the eighth or ninth invention, it is possible to effectively select the light guide path atmosphere with a relatively simple configuration.

Embodiments of the present invention will be described below with reference to the accompanying drawings. In the following drawings, the same members are denoted by the same reference numerals. In order to facilitate understanding, the scales of these drawings are appropriately changed.
FIG. 1 is a schematic diagram of a laser device according to the present invention. A laser apparatus 100 according to the present invention is mainly used for metal processing, and includes a laser oscillator 2 and a laser processing machine 11. As shown in FIG. 1, the laser oscillator 2 and the laser processing machine 11 are electrically connected to each other via a control device 1.

  The laser oscillator 2 is a relatively high-power laser gas oscillator of the induction discharge excitation type, for example, a carbon dioxide gas laser. The laser oscillator 2 includes a discharge tube 9 connected to a laser gas pressure control system 18. The laser gas pressure control system 18 can supply the laser gas to the discharge tube 9 and discharge the laser gas from the discharge tube 9 through the laser gas supply port 17 and the laser gas discharge port 19 formed in the laser oscillator 2. One end of the discharge tube 9 is provided with a rear mirror 6 (resonator internal mirror) that does not have partial transparency, and the other end of the discharge tube 9 is provided with an output mirror 8 that has partial transparency. The output mirror 8 is made of ZnSe, and the inner surface of the output mirror 8 is partially reflected and the outer surface of the output mirror 8 is totally reflected. A laser power sensor 5 is disposed on the rear surface of the rear mirror 6. As shown in the figure, two discharge sections 29 a and 29 b are provided in the optical resonance space of the discharge tube 9 between the rear mirror 6 and the output mirror 8.

  Each discharge section 29a, 29b includes a pair of discharge electrodes 7a, 7b arranged so as to sandwich the discharge tube 9, respectively. These discharge electrodes 7a and 7b have the same dimensions and are provided with a dielectric coating. As shown in FIG. 1, the discharge electrode 7 a is connected to the laser power source 4 via the matching circuit 3. The discharge electrode 7b is also connected to a laser power source through a similar matching circuit, but these are not shown for easy understanding. These laser power supplies are controlled independently, and the power supplied to the corresponding discharge sections 29a and 29b can be freely adjusted.

  Further, as shown in the figure, a blower 14 is disposed in the discharge tube 9, and heat exchangers 12 and 12 'are disposed upstream and downstream of the blower, respectively. Further, the laser oscillator 2 is connected to a cooling water circulation system 22 so that the laser gas in the discharge tube 9 is appropriately cooled.

  In FIG. 1, a high-speed axial flow type laser oscillator 2 is shown, but the laser oscillator 2 may be another type of laser oscillator, for example, a three-axis orthogonal type oscillator or a gas slab laser by thermal diffusion cooling. Good.

  The laser beam machine 11 is arranged so that the laser beam output from the output mirror 8 of the laser oscillator 2 can enter the laser beam machine 11. The laser processing machine 11 includes a reflecting mirror 10 that reflects an incident laser. As shown in the figure, the laser beam reflected by the reflecting mirror 10 is irradiated to the workpiece 20 on the machining table 21 through the condenser lens 13 and the machining head 16. Here, both surfaces of the condensing lens 13 made of ZnSe are coated with total reflection. Although not shown in the drawing, a parabolic mirror may be employed instead of the condenser lens 13.

  Further, the workpiece 20 is positioned at a predetermined location by changing the position of the machining table 21 in the horizontal direction. Further, as shown in FIG. 1, the laser processing machine 11 is provided with an assist gas supply system 15. Assist gas from an assist gas source (not shown) installed outside the laser processing machine 11 is supplied to a desired position of the processing head 16 by an assist gas supply system 15.

  Incidentally, as shown in FIG. 1, the light guide 30 is disposed between the laser oscillator 2 and the laser processing machine 11. More precisely, the light guide 30 is a hollow pipe connecting the output mirror 8 of the laser oscillator 2 and the condenser lens 13 of the laser processing machine 11. As shown in the drawing, the light guide path 30 is arranged coaxially with respect to the center line C of the laser output from the output mirror 8 and includes a reflecting mirror 10 that reflects the laser.

  In the first embodiment of the present invention, the laser device 100 includes the dehumidifier 40 connected to the opening 32 formed on the side surface of the light guide 30 by the supply passage 31. In the embodiment shown in FIG. 1, the supply passage 31 and the opening 32 associated therewith are positioned approximately at the center between the laser oscillator 2 and the laser processing machine 11. This dehumidifier 40 makes the water vapor | steam in air drop-like by contacting the air suck | inhaled from the outside with an internal cooler, and discharges dehumidified air with which water vapor | steam was reduced next. Of course, you may make it employ | adopt the dehumidifier 40 provided with the other mechanism which can remove the water vapor | steam in air. In FIG. 1, the dehumidifier 40 controlled by the control device 1 dehumidifies the air sucked from the outside and discharges it to the supply passage 31.

  FIG. 2 is a detailed view of the control device. The control device 1 for electrically connecting the laser oscillator 2 and the laser processing machine 11 is composed of a digital computer as shown in FIG. 2 and includes a ROM (read only memory) and a ROM connected to each other by a bidirectional bus 106. A storage unit 105 including a RAM (random access memory), a processing unit 104 such as a CPU (microprocessor), an input unit 102 as an input port, and an output unit 103 as an output port are provided. The input unit 102 and the output unit 103 are appropriately connected to predetermined components of the laser oscillator 2, the laser processing machine 11, the dehumidifier 40, and an air source 50 and a nitrogen source 60 described later.

  During the operation of the laser apparatus 100, the laser gas is supplied into the discharge tube 9 through the laser gas supply port 17 by the laser gas pressure control system 18. Next, the laser gas is circulated in a circulation path composed of the discharge tube 9 by the blower 14. As indicated by arrows in FIG. 1, the laser gas sent out from the blower 14 passes through a heat exchanger 12 ′ for removing compression heat and is supplied to the discharge sections 29a and 29b.

  When a predetermined voltage, for example, an alternating voltage of several hundred kHz to several tens of MHz is applied by the discharge electrodes 7a and 7b in the discharge sections 29a and 29b, the laser gas is excited by the discharge action, thereby generating a laser. According to a known principle, the laser is amplified in the optical resonance space, and the output laser is extracted through the output mirror 8. The laser gas having a high temperature due to the discharge action is cooled by the heat exchanger 12 and returns to the blower 14 again. At this time, it is assumed that the cooling water circulation system 22 operates and the laser gas in the discharge tube 9 is appropriately cooled.

  The laser extracted from the output mirror 8 is supplied from the laser oscillator 2 through the light guide 30 to the laser processing machine 11 as shown in the figure. In the laser processing machine 11, the laser is appropriately reflected by the reflecting mirror 10 disposed in the light guide path 30. The reflected laser beam is condensed by the condenser lens 13 and irradiated onto the workpiece 20 through the machining head 16. Thereby, the workpiece 20 on the machining table 21 can be machined, for example, cut or welded.

  In the present invention, the dehumidifier 40 is activated through the control device 1 when the laser is output from the laser oscillator 2. Thereby, the dehumidified air formed by the dehumidifier 40 flows into the light guide path 30 from the opening 32 through the supply path 31 as indicated by an arrow. This dehumidified air scavenges air that has been present in the light guide path 30 before the laser oscillator 2 is activated. Accordingly, when a predetermined time elapses after the dehumidifier 40 is activated, the air in the light guide path 30 is replaced with dehumidified air. Therefore, the laser output from the laser oscillator 2 propagates in the dehumidified air with reduced water vapor.

  FIG. 3 is a diagram showing the relationship between the atmosphere in the light guide and the laser beam diameter. In FIG. 3, the vertical axis indicates the laser beam diameter D of the laser measured in the vicinity of the condenser lens 13 in the light guide 30. The horizontal axis in FIG. 3 shows the atmosphere in the light guide 30, and the nitrogen (dry nitrogen) atmosphere and the carbon dioxide concentration-reduced air atmosphere in which the carbon dioxide (carbon dioxide) concentration is lowered in order from the left in FIG. 3 shows a dehumidified air atmosphere formed by the dehumidifier 40, a normal air atmosphere.

  Since carbon dioxide, water vapor, and / or organic gas, etc. are present in the air, when the laser propagates in normal air, the laser is absorbed and scattered by these carbon dioxide, etc., and the laser beam diameter D Will expand. Therefore, as shown in FIG. 3, the laser beam diameter D when the laser propagates in the air is the largest.

  On the other hand, when the laser propagates in a nitrogen atmosphere, since the nitrogen is an inert gas and does not contain carbon dioxide, water vapor, and / or organic gas, etc., the absorption and scattering of the laser is the smallest. The laser beam diameter D is also the smallest.

  The fact that the laser beam diameter D is small means that the absorption and scattering of the laser beam in the light guide 30 is small. Therefore, when the laser beam diameter D is small, the quality of the laser beam does not deteriorate, and the laser power in the workpiece 20 does not decrease. That is, when the laser beam diameter D is small, processing defects of the workpiece 20 do not occur. That is, when the laser beam diameter D is relatively small, it can be said that the beam atmosphere in the light guide 30 is good.

  In addition, when the laser propagates in the carbon dioxide concentration-reduced air atmosphere, the amount of carbon dioxide in the air is reduced, so that the absorption and scattering of the laser based on the carbon dioxide gas is also reduced as the carbon dioxide gas is reduced. In this case, since water vapor in the air is not removed, the laser beam diameter D is larger in the case of a carbon dioxide concentration-reduced air atmosphere than in the case of a nitrogen atmosphere, as shown in FIG.

  Further, when the laser propagates through the dehumidified air atmosphere formed by the dehumidifier 40 as in the first embodiment of the present invention, the amount of water vapor in the air is reduced. Also decreases with the reduction of water vapor. In this case, since carbon dioxide in the air is not removed, the laser beam diameter D is larger in a dehumidified air atmosphere than in a carbon dioxide concentration-reduced air atmosphere. In this case, the atmospheric dew point of the dehumidified air, that is, the temperature at which the water vapor contained in the air is cooled to form water droplets at atmospheric pressure is 0 ° C. or lower.

  However, as can be seen from FIG. 3, the laser beam diameter D in the three cases of the nitrogen atmosphere, the carbon dioxide concentration reduced air atmosphere, and the dehumidified air atmosphere is larger than the laser beam diameter D in the air atmosphere as compared with the case of the air atmosphere. And the difference in the laser beam diameter D between these three cases is extremely small. Therefore, in the three cases of the nitrogen atmosphere, the carbon dioxide concentration-reduced air atmosphere, and the dehumidified air atmosphere, the laser beam diameter D obtained in the vicinity of the condenser lens 13 is substantially the same, and the occurrence of machining defects in the workpiece 20 is also the same. It can be judged that there are few.

  In other words, even when the laser is propagated in the dehumidified air atmosphere from the dehumidifier 40 as in the present invention, the laser beam diameter is the same as that in the case of a nitrogen atmosphere and a carbon dioxide concentration-reduced air atmosphere with relatively high running costs. D and the machining result of the workpiece 20 are obtained. The dehumidifier 40 is available at a relatively low cost, and need only be driven only when the laser oscillator 2 outputs the laser. Therefore, the cost required to form the dehumidified air atmosphere in the light guide 30 using the dehumidifier 40 is significantly less than the cost required to form the nitrogen atmosphere and the carbon dioxide concentration reduced air atmosphere. . In other words, in the present invention, by supplying the dehumidified air formed by the dehumidifier 40 to the light guide 30, the beam atmosphere in the light guide can be favorably maintained at low cost.

  In the embodiment shown in FIG. 1, the dehumidifier 40 is connected to the light guide 30 via the supply passage 31, but a part of the dehumidifier 40 is not provided with the supply passage 31, but the opening of the light guide 30. 32 may be provided directly. In this case, the air in the light guide path 30 is sucked into the dehumidifier 40 from the portion of the dehumidifier 40 and dehumidified by the dehumidifier 40, and then the dehumidified air is sent back to the light guide path 30 through the opening 32. Like that. That is, a dehumidified air atmosphere is formed in the light guide 30 by directly dehumidifying the air in the light guide 30. Even in such a case, it is clear that the same effect as described above can be obtained.

  The supply passage 31 and the opening 32 associated therewith are preferably positioned substantially at the center between the output mirror 8 of the laser oscillator 2 and the condenser lens 13 of the laser processing machine 11. In such a case, the dehumidified air supplied from the opening 32 through the supply passage 31 is distributed almost evenly in the light guide 30, and the absorption scattering of the laser beam is evenly reduced over the entire light guide 30. be able to.

  Incidentally, as described above, in the present invention, the atmospheric pressure dew point of the dehumidified air formed by the dehumidifier 40 is 0 ° C. or less. On the other hand, when the atmospheric pressure dew point of the dehumidified air is greater than 0 ° C., water vapor is generated in the dehumidified air, so that absorption and scattering of the laser beam occurs and the laser beam diameter D increases, thereby forming a good beam atmosphere. Can not do it. In particular, in a high-temperature and high-humidity area, naturally, there is a large amount of water vapor in the air present in the light guide path 30, so that the laser beam is also easily absorbed and scattered. On the other hand, in the present invention, since the inside of the light guide path 30 is replaced by dehumidified air, the water vapor in the light guide path 30 is extremely less than the water vapor in the external air. Therefore, it is particularly advantageous to use the laser device 100 of the present invention in a hot and humid area.

  FIG. 4 is a schematic view of a laser device according to the second embodiment of the present invention. In FIG. 4 and FIG. 5 to be described later, members denoted by the same reference numerals as those in FIG. 1 are the same as those described with reference to FIG. In the second embodiment, the light guide 30 that connects the output mirror 8 and the condenser lens 13 is relatively long. In FIG. 4, the light guide path 30 is assumed to be longer than 10 m.

  In the second embodiment, two openings 32 a and 32 b are formed on the side surface of the light guide path 30. In order to distribute the dehumidified air evenly in the light guide path 30, the two openings 32 a and 32 b are formed at positions that substantially divide the entire light guide path 30 between the output mirror 8 and the condenser lens 13. Is preferred. Dehumidifiers 40a and 40b are connected to supply passages 31a and 31b extending from the openings 32a and 32b, respectively. These dehumidifiers 40a and 40b are the same as the dehumidifier 40 shown in the first embodiment.

  When the light guide path 30 is relatively long, the volume of the light guide path 30 naturally increases, so that it becomes difficult to supply a sufficient amount of dehumidified air to the light guide path so that the propagation change of the laser beam does not occur. It takes a considerable time to replace the light guide 30 with the dehumidified air only by the single dehumidifier 40. In the embodiment shown in FIG. 4, since the dehumidified air is supplied from a plurality of, for example, two dehumidifiers 40a and 40b, a sufficient amount of dehumidified air is introduced so that the propagation change of the laser beam does not occur. It can be supplied to the optical path, and the air in the light guide path 30 can be replaced with dehumidified air in a short time. In the present embodiment, it is preferable to supply the dehumidified air (per unit time) 60 times or more the entire volume of the light guide 30 into the light guide 30, and thereby, a laser beam of the same level as in a nitrogen atmosphere or the like. It becomes possible to ensure the diameter D. Therefore, also in the present embodiment, the beam atmosphere in the light guide path can be favorably maintained at a low cost. As a matter of course, a configuration including a larger number of dehumidifiers 40 may be used.

  By the way, when the occurrence of absorption / scattering of the laser beam is expected, the dehumidified air atmosphere may be switched to the carbon dioxide concentration reduced air atmosphere or the nitrogen atmosphere. FIG. 5 is a schematic view of a laser device according to the third embodiment of the present invention. In FIG. 5, a passage 49 extending from the dehumidifier 40 is connected to the supply passage 31 via a switching valve 70. Furthermore, passages 59 and 69 extending from the air source 50 and the nitrogen source 60 are also connected to the supply passage 31 via the switching valve 70.

  The air source 50 includes a molecular filter 51 inside. Air in the air source 50 is supplied to the passage 59 through the molecular filter 51. Since the molecular filter 51 serves to filter the carbon dioxide molecules, the air passes through the molecular filter 51, so that the carbon dioxide concentration is reduced. The molecular filter 51 is regenerated by supplying air in the reverse direction after a predetermined period of use or after processing a predetermined amount of air. On the other hand, the nitrogen source 60 is filled with dry nitrogen.

  The air source 50 and the nitrogen source 60 are electrically connected to the control device 1 so that air and nitrogen with a small amount of carbon dioxide gas are supplied to the corresponding passages 59 and 69, respectively, according to a command from the control device 1. It has become. Similarly, the switching valve 70 operates so that any one of the passages 49, 59, and 69 communicates with the supply passage 31 according to a command from the control device 1.

  In the third embodiment shown in FIG. 5, any one of dehumidified air, air with less carbon dioxide, and nitrogen can be supplied to the light guide 30 by appropriately switching the switching valve 70. Thereby, also in 3rd embodiment, the effect similar to having mentioned above can be acquired.

  Note that whether to select dehumidified air, air with less carbon dioxide, or nitrogen is determined based on, for example, the optical path length L, that is, the distance between the output mirror 8 and the condenser lens 13. Good. FIG. 6 is a flowchart for determining which atmosphere to use. In step 101 shown in FIG. 6, it is determined whether or not the optical path length L of the laser apparatus 100 is larger than a predetermined length L0. The optical path length L0 of the predetermined length is, for example, 10 m. When the optical path length L is equal to or shorter than the predetermined length L0, the routine proceeds to step 106, where the switching valve 70 is switched so that the dehumidified air from the dehumidifier 40 is used.

  When it is determined that the optical path length L is greater than the predetermined length L0, the routine proceeds to step 102 where it is determined whether or not the output P of the laser oscillator 2 is greater than a predetermined value P0. The predetermined value P0 is assumed to be 2 kW, for example. If it is determined that the output P is less than or equal to the predetermined value P0, the routine proceeds to step 106. In such a case, since it is determined that the propagation change of the laser beam is not so large that the workpiece 20 becomes defective, the switching valve 70 is switched to use the dehumidified air from the dehumidifier 40.

  On the other hand, when it is determined that the output P of the laser oscillator 2 is larger than the predetermined value P0, the routine proceeds to step 103, where it is further determined whether or not the optical path length L is larger than the predetermined value L1. The predetermined value L1 is larger than the predetermined value L0. When it is determined that the optical path length L is equal to or less than the predetermined value L1, the routine proceeds to step 105, where the switching valve 70 is switched so that the carbon dioxide concentration reduced air from the air source 50 is used. On the other hand, if it is determined that the optical path length L is greater than the predetermined value L1, the routine proceeds to step 104 where the switching valve 70 is switched to use the nitrogen gas from the nitrogen source 60.

  That is, as the optical path length L becomes longer, absorption and scattering of the laser beam can occur. Therefore, as the optical path length L becomes longer, the atmosphere in the light guide path is selected in the order of dehumidified air, carbon dioxide concentration-reducing air, and nitrogen gas. ing. In such a case, the use of carbon dioxide concentration-reduced air and nitrogen gas, which have a relatively high running cost, can be reduced as much as possible. Note that either nitrogen gas or carbon dioxide concentration-reduced air may be appropriately used without providing step 103 in FIG. In such a case, either the air source 50 or the nitrogen source 60 may be excluded.

  Further, whether to select dehumidified air, air with less carbon dioxide, or nitrogen may be determined based on the dimensions of the workpiece 20. FIG. 7 is another flowchart for determining which atmosphere is adopted. In step 201 in FIG. 7, it is determined whether or not the dimension of the workpiece 20, more precisely, the surface area A is larger than a predetermined value A <b> 1. When the surface area A of the workpiece 20 is equal to or less than the predetermined value A1, the process proceeds to step 205, and the switching valve 70 is switched to use dehumidified air.

  When the surface area A of the workpiece 20 is larger than the predetermined value A1, the routine proceeds to step 202, where it is further determined whether or not the surface area A is larger than the predetermined value A2 (A2> A1). When the surface area A is less than or equal to the predetermined value A2, the switching valve 70 is switched to use the carbon dioxide concentration-reduced air from the air source 50 (step 204), and the surface area A is greater than the predetermined value A2. The switching valve 70 is switched so that nitrogen from the nitrogen source 60 is used (step 203).

  As the size of the workpiece 20 increases, the length of the light guide 30 increases accordingly. Therefore, absorption and scattering of the laser beam may also occur. Therefore, as the size of the workpiece 20, for example, the surface area increases, dehumidified air, If carbon dioxide concentration-reduced air and nitrogen gas are selected in this order, the use of carbon dioxide concentration-reduced air and nitrogen gas, which have a relatively high running cost, can be minimized.

  Naturally, any one of dehumidified air, carbon dioxide concentration-reduced air, and nitrogen gas may be selected according to other parameters, for example, the energy density of the laser beam. In this case, as the energy density of the laser beam decreases, the dehumidified air, carbon dioxide concentration-reduced air, and nitrogen gas may be selected in this order. Further, it is within the scope of the present invention to appropriately combine some of the embodiments described above.

1 is a schematic diagram of a laser device according to a first embodiment of the present invention. It is detail drawing of a control apparatus. It is a figure which shows the relationship between the atmosphere in a light guide path, and a laser beam diameter in case a laser output is 5 kW and optical path length is 10 m. 2 is a schematic view of a laser device according to a second embodiment of the present invention. 4 is a schematic view of a laser device according to a third embodiment of the present invention. It is a flowchart at the time of determining which atmosphere is employ | adopted in the laser apparatus based on this invention. It is another flowchart at the time of determining which atmosphere is employ | adopted in the laser apparatus based on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Control apparatus 8 Output mirror 9 Discharge tube 10 Reflective mirror 11 Laser processing machine 13 Condensing lens 16 Processing head 20 Processing workpiece 21 Processing table 30 Light guide path 31 Supply path 31a, 31b Supply path 32 Opening part 32a, 32b Opening part 40 Dehumidification Dehumidifier 49 Passage 49, 59, 69 Passage 50 Air source 51 Molecular filter 60 Nitrogen source 70 Switching valve 100 Laser device

Claims (9)

A laser oscillator;
A condensing optical system for condensing the laser output from the laser oscillator;
A light guide that guides the laser from the laser oscillator to the condensing optical system;
A laser apparatus comprising a dehumidifying means for dehumidifying air in the light guide. A laser oscillator;
A condensing optical system for condensing the laser output from the laser oscillator;
A light guide that guides the laser from the laser oscillator to the condensing optical system;
A dehumidifying means for dehumidifying the air;
A laser apparatus comprising: supply means for supplying dehumidified air dehumidified by the dehumidifying means to the light guide path.   3. The laser device according to claim 1, wherein a plurality of dehumidifying means are included when a distance between the laser oscillator and the condensing optical system is larger than a predetermined value.   4. The laser device according to claim 1, wherein an atmospheric pressure dew point of the dehumidified air dehumidified by the dehumidifying means is 0 ° C. or less. 5. Furthermore, switching means provided in the supply means,
An air source connected to the switching means, the carbon dioxide concentration of the air in the air source is reduced to a predetermined carbon dioxide concentration,
5. The switching unit according to claim 2, wherein either one of the dehumidified air from the dehumidifying unit and the air from the air source is supplied to the light guide path through the supply unit. 6. The laser device described in 1. Switching means provided in the supply means;
A nitrogen source connected to the switching means,
5. The switch according to claim 2, wherein the switching unit supplies either the dehumidified air from the dehumidifying unit or the nitrogen from the nitrogen source to the light guide through the supply unit. 6. The laser apparatus described. Switching means provided in the supply means;
An air source connected to the switching means, the carbon dioxide concentration of the air in the air source is reduced to a predetermined carbon dioxide concentration,
Furthermore, comprising a nitrogen source connected to the switching means,
5. The switching means supplies either dehumidified air from the dehumidifying means, air from the air source, or nitrogen from the nitrogen source to the light guide through the supply means. The laser device according to any one of the above.   The laser device according to any one of claims 5 to 7, wherein a switching action of the switching unit is determined according to a distance between the laser oscillator and the condensing optical system. The laser focused by the focusing optical system is designed to process a workpiece.
The laser device according to any one of claims 5 to 7, wherein a switching action of the switching means is determined according to a dimension of the workpiece.

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