WO2005038998A1

WO2005038998A1 - Solid-state laser oscillator and solid-state laser beam apparatus

Info

Publication number: WO2005038998A1
Application number: PCT/JP2003/013280
Authority: WO
Inventors: Takeshi Morimoto; Toshiki Koshimae; Toshiaki Watanabe; Kenji Kumamoto
Original assignee: Mitsubishi Denki Kabushiki Kaisha
Priority date: 2003-10-17
Filing date: 2003-10-17
Publication date: 2005-04-28

Abstract

A solid-state laser oscillator and a solid-state laser beam apparatus using the solid-state laser oscillator are disclosed. Dissolved oxygen concentration in cooling water for cooling an LD heat sink in the oscillator is reduced so as to reduce corrosion of the LD heat sink. This enables to thin the LD heat sink, to improve the cooling effect of an LD, and to downsize the LD heat sink.

Description

Description Solid-state laser oscillator and solid-state laser processing equipment Technical field

The present invention relates to a solid-state laser oscillator and a solid-state laser processing device having a countermeasure for preventing corrosion of a heat sink of a semiconductor laser that excites a solid-state laser medium. Background art

FIG. 8 is a schematic configuration diagram showing an oscillator, a processing head, a workpiece, and a laser beam optical path of a conventional solid-state laser processing apparatus. 1 9 Oscillator head.

20 is a resonator, 21 is a partial reflection mirror, 22 is a total reflection mirror, 18 is a semiconductor laser (LD) module as an excitation light source, and 11 is a solid laser medium (eg, YAG) Reference numeral 23 denotes a cavity containing a pumping light source 18 and a solid-state laser medium 11, 24 denotes a laser beam emitted from the resonator 20, 25 denotes a magnifying lens, 26 denotes a collimating lens, 27 is a beam shirt consisting of a reflective mirror 28, a damper 29, etc., 28 is a reflective mirror, 29 is a damper, 30 is a condenser lens, 31 is a fiber holder,

Reference numeral 32 denotes an optical fiber composed of a condenser lens 30 and a fiber holder 31—an incident portion, 33 denotes an optical fiber, 34 denotes a processing head, and 35a and 35b denote processing lenses. Reference numeral 36 denotes a power supply device for supplying power to the oscillator head 19, and 37 a cooling device for circulating cooling water for cooling the module 18 and the solid-state laser medium 11 and performing heat exchange. Reference numeral 38 denotes a workpiece. In general, the combination of the oscillator head 19, the power supply 36 and the cooling device 37 is called an oscillator. Next, the operation of the oscillator will be described. In the oscillator head 19 of FIG. 8, the solid-state laser medium 11 is excited by the excitation light of the excitation light source 18, and is partially reflected by the partial reflection mirror 21 provided so as to sandwich the solid-state laser medium 11. Laser oscillation is generated by mirror 22. The laser beam 24 emitted from the resonator 20 is expanded by passing through a magnifying lens 25, and becomes a parallel beam by passing through a collimating lens 26. The collimated laser beam is an optical fiber. It enters the entrance 32.

A beam shirt 27 is provided between the collimating lens 26 and the optical fiber input section 32 so that the laser beam can be cut off when it is not desired to emit the laser beam outside the laser oscillator. . The beam shirt 27 consists of a reflecting mirror 28 that reflects the laser beam and a damper 29 that absorbs the laser beam and converts it into heat. The reflective mirror 28 is operable, so that when the reflective mirror is at position A, the laser beam passes through the beam shirt _27, but when the reflective mirror is at position B, the laser is The beam is reflected by the reflecting mirror 28 and reaches the damper 29. The surface of the damper 29 is composed of a laser beam absorber, and converts the energy of one laser beam into heat. Although not shown, the damper 29 is water-cooled to release the absorbed heat.

The collimated laser beam incident on the optical fiber input section 32 is condensed by the condensing lens 30 in the optical fiber input section 32, and is held by the fiber holder 31. The light enters the end face 33 of 33 and propagates in the optical fiber. The laser beam that has passed through the optical fiber 133 exits from the end surface 33 o of the optical fiber 33 connected to the processing head 34. The laser beam guided to the processing head 34 is condensed by the condensing lenses 35a and 35b and irradiates the workpiece 38, and the processing head 34 or the processing head is processed. Drilling, cutting, welding, etc. by moving 3 8 to the desired position The processing of is carried out.

YAG, YLF, ruby, glass, etc. are used as the solid-state laser medium in the solid-state laser oscillator. For example, the resonator of a solid-state laser oscillator using YAG is a YAG rod, which is a solid-state laser medium 11 sandwiched between two mirrors, a partial reflection mirror 3 and a total reflection mirror 14, as shown in Fig. 9. The laser light is extracted by exciting and oscillating a columnar crystal called “LD” 40 obtained from an LD module 18 as an excitation light source. Generally, a plurality of LD modules 18 are used side by side as shown in FIG. The characteristic of the YAG laser is that its wavelength is 1.0 βm, which is shorter than that of a CO 2 laser, which is 10 times shorter, so that fiber transmission is possible. However, there is a high demand in the current factory where there is a high demand for flexible production forms.

FIG. 10 is a schematic diagram of an LD module 18 used as an excitation light source. Reference numeral 12 denotes an LD, which is assembled so as to be sandwiched between the upper electrode 13a and the lower electrode 13b together with the insulator 39. Then, excitation light is obtained from the LD 12 by applying a voltage between the upper electrode 13 a and the lower electrode 13 b. Since the life of the LD is greatly influenced by the change in the temperature of the LD, the temperature of the LD must be kept as constant and low as possible in order to extend the life of the LD. Also, the wavelength of the LD light changes with the temperature of the LD, and if the wavelength of the LD light changes, the absorptance in the YAG changes, resulting in a change in beam quality and laser output, resulting in unstable processing quality. It is necessary to keep the temperature change of the LD small.

On the other hand, in a solid-state laser oscillator, the power input to the LD is changed to obtain the desired laser output. Changing the input power of the LD necessarily changes the temperature of the LD, but as mentioned above, the life of the LD is short if the temperature changes greatly. The output wavelength fluctuates. For this reason, in order to efficiently cool the heat generating part and reduce the temperature change of the LD, as shown in Fig. 11, cooling water is supplied to the lower electrode (hereinafter also referred to as LD heat sink) 13b, and the LD heater is cooled. The LD is indirectly cooled while directly cooling Tosink 13b. To further enhance the cooling effect, the thickness of the LD heat sink has been reduced to shorten the distance between the LD and the cooling water, and copper with good thermal conductivity has been used for the LD heat sink. Further, in the conventional solid-state laser oscillator described in Japanese Patent Application Laid-Open No. 2002-76500 and Japanese Patent Application Laid-Open No. Some of them control the change of LD wavelength and deterioration of life. Disclosure of the invention

By the way, copper, which is generally used as a heat sink, reacts with dissolved oxygen in water and corrodes. Therefore, a sufficient thickness is required to prevent perforation due to corrosion during the life of the product. For this reason, the distance between the LD and the cooling water becomes longer, and as a result, the heat radiation resistance increases, and the cooling effect of the LD decreases. In addition, the heat sink itself becomes larger, which is a major constraint on product design. .

On the other hand, in the conventional gas laser oscillator described in Japanese Patent Application Laid-Open No. Hei 8-380899, the brazing material and copper caused by phosphorus due to the dissolved oxygen in the cooling water flowing through the heat exchanger that cools the laser medium gas. In order to solve the problem of boundary corrosion progressing at the pipe boundary, causing holes in the heat exchanger and leakage of cooling water, the dissolved oxygen in the cooling water was reduced by installing a deoxygenator in the cooling water circulation path. There is a technology to prevent corrosion. However, in the present invention, the thickness of the LD heat sink must be increased in order to prevent the LD heat sink from being corroded by cooling water flowing through the LD heat sink of the solid-state laser oscillator. Therefore, the cooling effect of the LD is reduced, and the problem when the LD heat sink is enlarged is solved, and both the configuration and the problem are described in Japanese Patent Application Laid-Open No. 8-3066989. It is different from technology.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is possible to reduce the thickness of an LD heat sink by reducing the dissolved oxygen concentration during cooling and reducing the corrosion of an LD heat sink. It is an object of the present invention to provide a solid-state laser oscillator capable of improving the cooling effect of an LD and reducing the size of an LD heat sink and a solid-state laser processing apparatus using the solid-state laser oscillator.

In the solid-state laser oscillator and the solid-state laser processing device according to the present invention, a deoxygenating device is provided in a circulation path for circulating cooling water for cooling the LD for exciting the solid-state laser medium.

In the solid-state laser oscillator according to the present invention, a deoxygenation device is provided in a circulation path for circulating cooling water for cooling the LD that excites the solid-state laser medium, thereby reducing the concentration of dissolved oxygen in the cooling water and reducing the LD concentration. By reducing the corrosion of the heat sink, the thickness of the LD heat sink can be reduced, the cooling effect of the LD can be improved, and the LD heat sink can be downsized. Further, in the solid-state laser beam machine according to the present invention, since the cooling effect of the LD is improved, the beam quality and laser output of the laser oscillated from the solid-state laser medium are stabilized, and the processing quality can be stabilized. Brief Description of Drawings

FIG. 1 is a configuration diagram showing a solid-state laser processing apparatus and an oscillator based on Embodiment 1 of the present invention.

FIG. 2 is a configuration diagram showing a part of the solid-state laser oscillator according to the first embodiment of the present invention. ' FIG. 3 is a flowchart showing the control of the operation of the deoxidizer by the control device.

Fig. 4 is a graph showing the relationship between the temperature of water flowing through the deoxygenation unit, the amount of water flowing through the deoxygenation unit, and the vacuum pressure in the deoxygenation unit. It is.

FIG. 5 is a flowchart showing a flow for controlling the deoxidizing ability of the deoxidizing apparatus.

FIG. 6 is a configuration diagram showing a part of the solid-state laser oscillator according to the second embodiment of the present invention.

FIG. 7 is a configuration diagram showing a part of a solid-state laser oscillator based on Embodiment 3 of the present invention.

FIG. 8 is a configuration diagram of a conventional solid-state laser processing device and an oscillator. FIG. 9 is a configuration diagram of a resonator in a conventional solid-state laser oscillator. FIG. 10 is a schematic diagram of a conventional LD module.

FIG. 11 is a side view and a sectional view of a conventional LD module. BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1

FIG. 1 shows a solid-state laser processing apparatus and a solid-state laser oscillator according to a first embodiment for carrying out the present invention. The same components as those of the conventional laser processing apparatus shown in FIG. As shown in FIG. 1, the solid-state laser processing apparatus according to the present invention includes a cooling device 37 for cooling an LD or the like, a deoxygenating device 16 for reducing the concentration of dissolved oxygen in the cooling water, and a control device 1 for controlling the operation thereof. It is equipped with 7. FIG. 2 shows a detailed configuration of the cooling device 37, the deoxygenation device 16 and the control device 17. In Fig. 2, 1 is a heat exchanger that removes the heat of the LD and cools the warmed cooling water. Is a cooling tank that stores the cooled cooling water, 3a and 3b are flow meters that determine the flow rate of the cooling water, 4a and 4b are filters that remove dust, etc., 7 is a hollow fiber membrane, etc. Deoxygenation units that can be constructed, 6 is a vacuum pump that reduces the pressure inside the deoxygenation unit, 8 is a pressure gauge that measures the vacuum pressure inside the deoxygenation unit, 5 is a solenoid valve, 9 is a pure unit, 10 is Pump for forced circulation of cooling water, 17 is a control unit, 1 a is a storage unit in the control unit, 17 b is a calculation unit in the control unit, .17 c is a control unit in the control unit, 18 Is an LD module. The LD module 18 constitutes the resonator shown in FIG. 9 and is incorporated in the solid-state laser oscillator and solid-state laser processing apparatus shown in FIG.

Next, the operation will be described. As shown in Fig. 2, the cooling water branches off from the cooling water tank 2 via the pump 10 and one is supplied to the LD heat sink 13b through the filter 4b and the LD heat sink 13b The LD 12 takes away the generated heat, and then returns to the cooling water tank 2 through the heat exchanger 1. The other branch via pump 10 passes through valve 15a, pure water 9 and deoxygenation unit 7, and returns to cooling water tank 2.

Pure water device 9 is turned LD heat one sink 1 3 b are electrodes as _c above, which is provided for keeping the coolant pure hydrated and conductivity low <, if electrical. Conductivity high cooling This is to prevent the power supply unit and LD 12 from being destroyed when water flows through the LD heat sink 13 b, causing electricity to flow through the cooling water and ground fault.

The deoxygenator 16 comprises a vacuum pump 6, a deoxygenating unit 7 composed of a hollow fiber membrane, etc., and a flow meter 3a, a pressure gauge 8, a solenoid valve 5, and a filter 4a for controlling the deoxygenating unit 7. It is added and installed in parallel with LD heat sink 13b. The gas (oxygen) in the cooling water is removed from the cooling water flowing through the deoxygenation unit 7 by reducing the pressure inside the deoxygenation unit by the vacuum pump 6 connected to the deoxygenation unit 7. . At this time, the cooling water temperature, The temperature inside the deoxygenation L nit and the amount of cooling water flowing into the deoxygenation unit are measured with a water temperature gauge 14, a pressure gauge 8, and a flow meter 3a, respectively, and the signals from these measuring instruments are controlled by the controller. The operation of the deoxygenator 16 is controlled by transmitting it to 17. The control device 17 compares the data transmitted from the various measuring instruments with the setting values stored in the memory 17a of the storage unit 17a storing various set values, or An operation unit 17b for performing calculations and a control unit 17c for controlling operations such as a pump valve are provided.

Next, the operation control of the deoxidizer 16 by the controller 17 will be described with reference to the flowchart of FIG.

S001: The pump 10 is started by a signal from the control unit 17c of the control device 17.

The S 002 valve 15a is opened and water is passed through the pure water device 9 and the deoxygenating unit 7, and the vacuum pump 6 is driven.

S 00 3 The solenoid valve 5 is kept “open.” By taking in outside air into the vacuum pump 6, moisture and foreign substances in the vacuum pump 6 are removed, and the performance is secured. (Prolapse

S004: After a specified time (several minutes), the solenoid valve 5 is closed, and the inside of the deoxygenating unit 7 is evacuated, so that the gas (oxygen) can be removed from the cooling water flowing through the deoxidizing unit 7. Etc.). (Normal operation of deoxidizer)

The following is the operation when the pressure inside the deoxygenating unit is abnormal during the normal operation of the deoxidizer.

S 005: During normal operation of the deoxygenator, the vacuum pressure in the deoxygenator unit 7 is measured by the pressure gauge 8, the measurement data is transmitted to the controller 17, and the storage unit 1 is stored in the controller 17. The calculation unit 17b compares the vacuum pressure set value in 7a with the measurement data to determine whether the vacuum pressure is normal.

S06: When determined to be abnormal, the number of vacuum pressure abnormalities stored in storage unit 17a Is added by the operation unit 17b.

S O 07: The cumulative number of abnormalities in the storage unit 17 a is compared with the specified value N in the calculation unit 17 b.

SO 08: If the cumulative number of abnormalities is equal to or less than the specified value N, the solenoid valve 5 is opened for several minutes by the control unit 17c, and the water or foreign matter in the vacuum pump, which may be the cause of the vacuum pressure abnormality, is discharged to the outside. Let

S09: After a few minutes, the solenoid valve 5 is closed by the control unit 17c, and the deoxidizer returns to normal operation (return to S004).

S 0 1 0 ': (One branch of S 0 7) If the cumulative number of vacuum pressure abnormalities is equal to or greater than the specified value N, the vacuum pressure abnormality is indicated by the indicator or indicator in the controller 17 And inform the operator.

S 0 1 1: The vacuum pump 6 is stopped by the control unit 17 c, the solenoid valve 5 is opened, the knob 15 a is closed, and the operation of the deoxidizer 16 is stopped. At this time, by opening the valve 15 b and bypassing the deoxygenation device 16, the oscillator and the pure water device 9 continue to operate as usual (continue to SO 12).

'The following is the operation when the amount of cooling water is abnormal during the normal operation of the deoxidizer. S012: (One branch of S005) When the vacuum pressure is normal, the flow rate of cooling water flowing into the deoxygenation unit 7 is measured by the flow meter 3a, and the measurement data is sent to the control unit 1. The control unit 17 compares the flow rate set value in the storage unit 17a with the measurement data in the control unit 17 to determine whether the flow rate is normal by comparing it in the calculation unit 17b.

S013: When it is determined that the flow rate is abnormal, the operator is informed of the flow rate abnormality by the indicator or indicator lamp on the controller 17 to notify the operator.

S0114: It is considered that the abnormal flow rate was caused by some cause in the piping leading to the deoxygenation unit 7 or the LD cooling water system. In this case, the cooling of the LD 12 is not performed and the LD 12 may be thermally damaged. Stop the oscillator, deionizer 9 and deoxygenator 16 by 1 7 c

0 stop, vacuum pump 6 stop, solenoid valve 5 open, valve 15 a closed).

S 0 16: (one branch of S 0 1 2) When the flow rate of the cooling water is normal, if there is a command to stop the oscillator, the control unit 17 c stops the pure water device 9 and the deoxygenation device 16 ( Pump 10 stopped, vacuum pump 6 stopped, solenoid valve 5 opened, valve 15a closed). If there is no command to stop the oscillator, return to normal operation (return to SO04).

As described above, by providing a deoxygenator 16 in the circulation path of the cooling water that cools the LD 12, the dissolved oxygen concentration in the cooling water can be reduced, and the corrosion of the LD heat sink 13 b is prevented. be able to. This makes it possible to reduce the thickness of the LD heat sink 13b, thereby improving the cooling effect of the LD 12 and miniaturizing the LD heat sink 13b. Further, since the cooling effect of the LD is improved, the life of the LD is prolonged, and the maintenance cost can be reduced. Further, since the laser wavelength of the LD is stabilized by the improvement of the cooling effect of the LD, the beam quality and laser output of the laser output from the solid-state laser medium 11 are stabilized, and the processing quality is improved. In addition, by providing a pressure gauge 8 for measuring the vacuum pressure inside the deoxidizing unit 7 and a flow meter 3a for measuring the flow rate of the cooling water passing through the deoxidizing unit 7, it is possible to know the abnormality of the device quickly. For example, it is possible to prevent the dissolved oxygen concentration from deteriorating due to an abnormality in the deoxidizer 16 and the thermal destruction of the LD 12 beforehand.

Next, a control method for correcting a change in the capacity of the deoxygenating unit 7 in response to a sudden change in the cooling water temperature will be described.

The deoxidizing capacity of the deoxidizing unit 7 varies greatly depending on the temperature of the water flowing through the deoxidizing unit 7. When the water temperature falls from T1 to T2 as shown in Fig. 4a, the deoxidizing capacity of the deoxidizer deteriorates from D01 to D02. This is a characteristic of the hollow fiber membrane used as the deoxygenation unit 7, and the water temperature rises. The deaeration performance is improved because the boundary resistance formed by the laminar flow (the vicinity of the interface, in this case, the difficulty of moving gas between the cooling water and the inner wall of the deoxygenating unit) is reduced. Conversely, when the water temperature is low, the deaeration capacity decreases due to the large boundary resistance.o

In the case of a laser oscillator, the temperature of the cooling water changes significantly due to changes in the installation environment and laser output (LD input power). For example, installation environment specifications of the laser oscillator is 5 ° C~35 ^e C, also the deoxygenation device 1 6 is normally used when the water temperature is 5 ° C decreases, the deoxidizing ability is decreased by about 20% . If the water temperature changes to the same level as the oscillator installation environment, the deoxygenator 16 will be large-scale to obtain a sufficient deoxygenation effect over the entire temperature range. Therefore, it is necessary to measure the water temperature and perform control appropriate to the change in deoxygenation capacity.

In the present invention, the oxygen removal capacity of the oxygen absorber is changed by the flow rate of the cooling water passing through the oxygen absorber and the vacuum pressure in the oxygen absorber, and the oxygen is passed through the oxygen absorber 7. (1) Correction by cooling water flow rate and (2) Correction by deoxygenation unit internal pressure are applied as control methods to correct the change in deoxygenation capacity with respect to the change in cooling water temperature. Hereinafter, (1) and (2) will be described.

(1) The capacity of the deoxygenation unit with respect to the cooling water flow rate is shown in Figure 4.b. As the flow rate decreases, the deoxygenation capacity increases. Therefore, as shown in Fig. 4b, when the water temperature drops from T1 ° C to T2 ° C and the deoxygenation capacity deteriorates from D01 [ppm] to D02 [ppm], the cooling water flow rate is changed to F1 [L / min] to F 2 [L / min], the deoxygenation capacity can be restored to D 01 [ppm]. In the correction based on the cooling water flow rate, by controlling the valve 15a as a flow rate adjusting means and controlling the flow rate of the cooling water flowing into the deoxidizing unit 7, the dissolved acid of the cooling water after passing through the hollow fiber membrane deoxidizing unit is adjusted. Reduce the elemental amount to below the target dissolved oxygen concentration D 01 [ppm].

The details of the operation are described below using the flowchart in Fig. 5a. S 101: Measure the cooling water temperature with a thermometer 14 (at this time, the cooling water flow rate F 1 [L / min]). Here, it is assumed that the outside air temperature drops rapidly and the cooling water temperature changes from T 1 ° C to T 2 ° C.

S102: The capacity of the deoxidizer 16 decreases due to the decrease in cooling water temperature, and the amount of dissolved oxygen in the cooling water increases. Water temperature T 2 ° based on the value sent from the water temperature gauge 14 to the controller 17 and the data on the relationship between the water temperature and the deoxidizer capacity stored in the memory 17a of the controller 17 The amount of dissolved oxygen D 0 2 [p pm] at C is calculated by the operation unit 17 b of the controller 17.

S103: Cooling required to keep the calculated dissolved oxygen content DO2 [ppm] (> specified value DO1 [ppm]) below the specified value D01 [ppm] at the cooling water temperature T2 ° C The water flow rate F 2 [L / min] is stored in the calculation unit 17 b of the control unit 1.7 based on the relationship data between the flow rate and the deoxidizer capacity stored in the storage unit 17 a of the control unit 17. Calculate.

S104: Control unit 17c of control unit 17 adjusts the opening of pulp 15a so that the cooling water flow rate calculated by operation unit 17b of control unit 17 is reached, and the amount of cooling water To adjust.

S105: When there is no command to stop the pure water system, return to water temperature measurement (return to S101).

S106: If a stop command is issued, open pump 10, vacuum pump 6, and solenoid valve 5, and stop the pure water system.

In the present invention, the flow rate adjusting means of the cooling water flow rate is set to the opening degree of the valve 15a. At this time, of course, the total flow rate of the cooling water flowing through the pump 10 must be equal to or greater than the sum of the flow rate into the deoxygenation unit 7 and the minimum cooling water flow required for LD cooling. Absent.

(2) Next, as shown in Figure 4c, the capacity of the deoxygenation unit with respect to the vacuum pressure inside the deoxygenation unit increases as the vacuum pressure decreases. Therefore, as shown in Fig. 4c, when the water temperature drops from T1 ° C to T2 ° C and the deoxygenation capacity deteriorates from D01 [ppm] to D02 [ppm], the vacuum pressure is changed to P1 [Pa ] To P 2 [P a], the deoxygenation ability can be restored to D 01 [p P m]. In the correction based on the pressure inside the deoxygenating unit, the rotation of the vacuum pump 6 is controlled as a pressure adjusting means, and the vacuum pressure in the deoxidizing unit 7 is controlled, so that the hollow fiber membrane deoxygenating unit is passed. [Reduce the dissolved oxygen content of wheat cooling water to the target dissolved oxygen concentration D 01 [ppm] or less.

The details of the operation will be described below using the flowchart of FIG. 5B. S201: Measure the cooling water temperature with a thermometer 14 (at this time, the pressure inside the deoxidizing unit P1 [Pa]). Here, it is assumed that the outside air temperature drops rapidly and the cooling ice temperature changes from T 1 ° C to T 2 ° C.

S202: The capacity of the deoxygenator 16 decreases due to the decrease in cooling water temperature, and the amount of dissolved oxygen in the cooling water increases. Water temperature T 2 ° C based on the value sent from the water temperature gauge 14 to the controller 17 and the data on the relationship between the water temperature and the deoxidizer capacity stored in the memory 17a of the controller 17 Calculate the dissolved oxygen amount D 0 2 [ppm] at the calculation unit 17 b of the control device.

S 203: Deoxygenation required to keep the calculated dissolved oxygen amount DO 2 [ppm] (> specified value D 01 [ppm]) below the specified value DO 1 [p pm] at the cooling water temperature T 2 ° C The unit pressure P 2 [Pa] is stored in the storage unit 17 a of the control unit 17. The relationship between the vacuum pressure stored in the storage unit 17 a and the capacity of the deoxidizing unit 17 Calculate with b.

S204: Inside the deoxygenation unit calculated by the operation unit 17b of the controller 17 According to the pressure, the control unit 17c of the control device 17 adjusts the rotation speed of the vacuum pump 6 to adjust the vacuum pressure.

S205: Return to water temperature measurement if there is no command to stop the pure water system (Return to S201)

S206: If a stop command is issued, open pump 10, vacuum pump 6, and solenoid valve 5, and stop the pure water system.

By controlling the flow rate and vacuum pressure, the dissolved oxygen concentration in the cooling water after passing through the hollow fiber membrane deoxygenating unit is controlled to the specified value D 0 1 [ppm] or less, and the deoxygenating capacity decreases due to the change in cooling water temperature. Supplement. It is desirable to use the two control methods depending on the cooling water path configuration. Of course, they can be used together. ■

In the first embodiment, the flow rate of the deoxidizer 17 and that of the deionizer 9 are the same.If the flow rate is reduced to secure the dissolved oxygen concentration, the flow rate to the deionizer 9 is reduced, and the cooling is performed. The conductivity of the water increases. If the conductivity of the cooling water rises, there is a concern that L 12 and power supply may be destroyed due to ground fault. For this reason, in a configuration such as the present embodiment in which the purifier 9 wants to secure a flow rate, it is more appropriate to control the dissolved oxygen concentration by the deoxidizer 16 by controlling the rotation speed of the vacuum pump 6 and controlling the vacuum pressure. I have.

As described above, a thermometer 14 for measuring the temperature of the cooling water is provided to measure the temperature of the water, and a pressure adjusting means (for example, a vacuum pump 6) for adjusting the vacuum pressure in the deoxygenating unit 7 according to the change in the temperature of the water. By controlling the water flow rate adjusting means (for example, valve 15 and pump 10) that adjusts the flow rate of the cooling water flowing through the deoxygenating unit, it is possible to suppress the decrease in the capacity of the oxygen device due to a change in the water temperature. There is no need to introduce a suitable deoxidizer.

Embodiment 2

Embodiment 2 A solid-state laser processing apparatus and a solid-state laser processing apparatus according to Embodiment 2 for carrying out the present invention. The configuration of the solid-state laser oscillator is the same as that of the first embodiment shown in FIG. However, since the detailed configurations of the cooling device 37, the deoxygenation device 16 and the control device 17 are different, they will be described with reference to FIG. Regarding the installation of the deoxidizer 16, in addition to FIG. 2, there is an installation case as shown in FIG. 6 and FIG. 7 described in the third embodiment. In FIG. 6, the deoxidizer 16 is connected to the LD heat sink 13 b And the water purifier 9 are installed in parallel. The advantage is that if the deoxidizer 16 fails, the valve 15a can be closed and the deoxidizer 16 can be replaced while the pure water device 9 is operating. In the installation method shown in Figs. 2 and 6, a pump is installed in series with the flow meter 3a, and the flow rate of the cooling water flowing into the deoxidizer Γ6 can be controlled independently by controlling the rotation speed of the pump. It can be used as a flow control means instead of the valve 15a.

In this embodiment, since there is nothing to limit the amount of cooling water flowing to the deoxygenating unit 7 as in Embodiments 1 and 3, it is more appropriate to perform the flow control 1.7. When the flow rate control is performed, a large vacuum pump for obtaining a high vacuum pressure is not required, so that the size and weight of the apparatus can be reduced. (On the other hand, it takes more time for the amount of dissolved oxygen in the cooling water to fall below the reference value than in other embodiments.)

Embodiment 3.

The configurations of the solid-state laser processing apparatus and the solid-state laser oscillator according to the third embodiment for carrying out the present invention are the same as those in FIG. 1 of the first embodiment. However, since the detailed configurations of the cooling device 37, the deoxygenation device 16 and the control device 17 are different, they will be described with reference to FIG. In FIG. 7, the deoxidizer 16 is installed in series with the LD heat sink 13b and the filter 4b. The advantage is that the installation method shown in FIGS. 2 and 6 can be used to reliably control the dissolved oxygen concentration. In Fig. 7, since the deoxygenator 16 is installed in series with the LD heat sink, the water in the cooling water tank circulates several times to reduce the dissolved oxygen concentration. Dissolved oxygen concentration can be controlled more quickly and more reliably than the methods shown in Figs. On the other hand, since it is necessary to realize a low dissolved oxygen concentration at a large flow rate, a large number of deoxygenating units 7 are required and the size becomes large. In the case of this embodiment, the oscillator cooling water amount is determined from the cooling efficiency of the LD 12, and a larger amount of cooling water flows through the deoxidizer 16 than in the first and second embodiments. As the flow rate increases, the dissolved oxygen concentration of the cooling water after passing through one deoxygenating unit increases, so in order to achieve the specified dissolved oxygen concentration, increase the number of deoxygenating units or reduce the degree of pressure reduction. I have to increase it. An increase in the number of deoxygenating units increases cost and size, and so control by vacuum pressure is more advantageous. Industrial applicability

As described above, the solid-state laser oscillator and the solid-state laser processing apparatus according to the present invention are suitable for use in processing such as drilling, cutting, and welding with a laser beam.

Claims

The scope of the claims

1. Solid state laser medium,

A semiconductor laser that excites the solid-state laser medium;

A heat sink arranged in contact with the semiconductor laser;

A circulation path for circulating cooling water for cooling the heat sink;

A solid-state laser oscillator comprising: a deoxygenating device provided in the circulation path.

2. The solid-state laser oscillator according to claim 1, wherein the deoxidizer is provided in series with the circulation path.

3. The solid-state laser oscillator according to claim 1, wherein the deoxidizer is provided in parallel with the circulation path.

4. The deoxygenator is

A deoxygenation unit consisting of a hollow fiber membrane, etc.

4. The solid-state laser oscillator according to claim 1, comprising a vacuum pump for evacuating the inside of the deoxygenating unit.

5. a pressure gauge for detecting a vacuum pressure in the deoxygenating unit;

5. The solid-state laser oscillator according to claim 4, further comprising a control device that outputs an abnormal signal when the vacuum pressure detected by the pressure gauge exceeds a set range value.

6. A flow meter for detecting the flow rate of the cooling water passing through the deoxygenating unit, and a control device for outputting an abnormal signal when the flow rate detected by the flow meter exceeds a set range value. The solid-state laser oscillator according to claim 4 or claim 5.

7. a thermometer for detecting the temperature of the cooling water;

A flow meter for detecting a flow rate of the cooling water passing through the deoxygenating unit; and a flow rate adjusting means for adjusting a flow rate of the cooling water passing through the deoxygenating unit. The temperature of the cooling water detected by the thermometer Exceeds the setting range, The solid-state laser according to any one of claims 4 to 6, further comprising a control device that changes a flow rate of the cooling water passing through the deoxygenating unit by the flow rate adjusting unit. Oscillator.

8. The control device includes:

A storage unit that stores the amount of change in the deoxidizing capacity of the deoxygenating device due to the change in the temperature of the cooling water, and the amount of change in the deoxidizing capability of the deoxidizing device due to the change in the amount of cooling water passing through the deoxidizing unit. When,

A calculating unit that calculates a deoxygenation capacity changed by a change in the water temperature of the cooling water, and calculates a water amount of the cooling water for restoring the changed deoxygenation capacity;

8. The solid-state laser oscillator according to claim 7, further comprising a control unit that controls a water amount adjusting unit to realize the water amount.

9. a thermometer for detecting a temperature of the cooling water;

A pressure gauge for detecting a vacuum pressure in the deoxygenating unit;

Pressure adjusting means for adjusting the vacuum pressure in the deoxygenating unit; and when the temperature of the cooling water detected by the thermometer exceeds a set range, the pressure adjusting means adjusts the vacuum pressure in the oxygen unit. The solid-state laser oscillator according to any one of claims 4 to 8, further comprising a control device for changing the value.

1 0. The control means:

A storage unit that stores a change in the oxygen removal capacity of the oxygen absorber due to a change in the temperature of the cooling water, and an amount of change in the oxygen removal capacity of the oxygen absorber due to a change in the vacuum pressure in the oxygen absorber.

A calculating unit that calculates a deoxidation capacity changed by a change in the temperature of the cooling water and calculates a vacuum pressure for restoring the changed deoxygenation capacity; 10. The solid-state laser oscillator according to claim 9, comprising: a control unit that controls a pressure adjusting unit to realize the vacuum pressure.

1 1. Equipped with a processing head that irradiates the laser beam output from the solid-state laser oscillator onto the workpiece,

10. A solid-state laser processing apparatus comprising the solid-state laser oscillator according to any one of claims 1 to 10.