JP6435153B2 - Laser resonator, laser processing apparatus, and laser resonator dehumidification method - Google Patents

Description

  The present invention relates to a laser resonator, a laser processing apparatus, and a laser resonator dehumidification method.

2. Description of the Related Art Conventionally, as a laser processing apparatus for processing a sheet metal, an apparatus using a carbon dioxide (CO ₂ ) laser oscillator, a YAG laser oscillator, or a fiber laser oscillator as a laser light source is known. The fiber laser oscillator has advantages such as better light quality and extremely high oscillation efficiency than the YAG laser oscillator. For this reason, a fiber laser processing apparatus using a fiber laser oscillator is used for industrial purposes, particularly for sheet metal processing (cutting or welding). In recent years, DDL processing apparatuses using a direct diode laser (DDL) oscillator as a laser light source have been developed.

  The fiber laser oscillator includes a housing, a light engine housed in a substantially sealed state in the housing, a control device that controls an oscillation operation, and a cooling device. The light engine includes a plurality of laser modules each having a semiconductor laser as a laser light source, and a combiner that combines laser beams generated by the laser modules. The laser beam combined by the combiner is output to the outside through the process fiber.

  Generally, the laser oscillation efficiency of a semiconductor laser has temperature dependence. Therefore, it is necessary to maintain the temperature of the light engine that generates heat with the oscillation of the laser light at an appropriate temperature by cooling so that high oscillation efficiency is always obtained. A cooling device is provided to maintain an appropriate temperature of the light engine. This cooling is usually performed by flowing and circulating, for example, cooling water at 24 ° C. into a cooling water channel (cooling pipe) disposed in the housing.

  By the way, if the amount of water vapor contained in the air in the housing exceeds the amount of saturated water vapor at the temperature of the cooling water, condensation may occur on the surface of the cooling pipe, causing problems in electronic components in the light engine. Increases nature. Therefore, it is necessary to inject the cooling water into the cooling pipe after sufficiently reducing the humidity of the air in the housing and the air in the laser module with a dehumidifier.

  Conventionally, there has been known a laser oscillator that uses compressed air that can be supplied abundantly as purge air from the outside during dehumidification, uses this compressed air as dry air with a low dew point by a gas separation membrane module, and supplies this to a plurality of laser modules. (See Patent Document 1).

JP 2013-239696 A

  In Patent Document 1, it is also proposed that dry air supply and dehumidification inside a casing by an air conditioner are simultaneously performed in a dehumidifying operation before the start of laser oscillation. However, Patent Document 1 does not sufficiently study control of the air conditioner operation after the start of laser oscillation, and there is room for study to obtain high oscillation efficiency after the start of laser oscillation.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a laser resonator, a laser processing apparatus, and a laser resonator dehumidification method that can appropriately prevent dew condensation in a housing that houses a laser diode. Is to provide.

According to one aspect of the present invention, a laser module that houses a laser diode that oscillates a laser, a housing that houses the laser module, a cooling path connected to the laser module, and a purge that is supplied from the outside An air purge unit that generates dry air having a low dew point from compressed air and supplies the dry air to the laser module via an air supply path, and has a blower opening in the housing, and is provided in the housing in parallel with the supply of dry air by the air purge unit. comprising of the air conditioner for controlling the by Ri temperature before Symbol dry air to control the temperature, wherein the air supply path, the laser resonator is routed in the vicinity of the air blowing port, a laser processing apparatus and laser resonator A method of dehumidifying a vessel is provided.

  According to the present invention, it is possible to provide a laser resonator, a laser processing apparatus, and a laser resonator dehumidification method that can appropriately prevent dew condensation in a housing that houses a laser diode.

1 is an overall view for explaining a laser processing apparatus according to an embodiment of the present invention. It is a figure for demonstrating the laser oscillator which concerns on embodiment of this invention. It is a figure for demonstrating the air purge unit of the laser processing apparatus which concerns on embodiment of this invention. It is a graph for demonstrating the time transition of the purge air temperature of the laser processing apparatus which concerns on embodiment of this invention, the temperature in a housing | casing, and external temperature. In the laser machining apparatus according to an embodiment of the present invention, in the case where the non-use using air conditioner is a graph illustrating the time course of the dew point temperature of the purge air in the laser module. It is a graph for demonstrating temporal transition of the air-conditioner side temperature of the laser processing apparatus which concerns on embodiment of this invention, an opposite side temperature, and external temperature. It is a flowchart which shows an example of the dehumidification method of the laser oscillator which concerns on embodiment of this invention.

  Embodiments of the present invention will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals.

  A fiber laser processing apparatus will be described as an example of a laser processing apparatus according to an embodiment of the present invention. As shown in FIG. 1, the fiber laser processing apparatus 51 includes a laser processing machine 10 that performs laser processing on a workpiece W, and a laser oscillator 1 that supplies laser light to the laser processing machine 10 via a process fiber FB1. And an air purge unit 20 for supplying dry air having a low dew point to the laser oscillator 1 via the air supply path AR1 and to the laser processing machine 10 via the air supply path AR2.

  The laser processing machine 10 includes a collimator unit 13 that collimates the laser light L emitted from the exit end face of the process fiber FB1 by the collimator lens 12, and a bend that reflects the laser light collimated by the collimator lens 12. A mirror 14, a laser head 16 that condenses the laser light reflected by the bend mirror 14 into a high energy density laser light by the condenser lens 15, and a processing table on which a work W that performs processing by the condensed laser light is installed. 18. The collimator unit 13 can introduce dry air having a low dew point supplied from the air supply path AR2 into the inside thereof, thereby preventing dust from entering the optical path.

  Next, the laser oscillator 1 will be described with reference mainly to FIG. As shown in FIG. 2, the laser oscillator 1 includes a housing KT, a light engine EG housed in a substantially sealed state inside the housing KT, a control unit SG that controls the operation of the laser oscillator 1, and a power supply unit. It has PW, cooling part RF, and the air-conditioning equipment (air conditioner) C attached to the housing | casing KT. The control unit SG and the power supply unit PW also have a casing SG1 and a casing PW1, respectively, and the inside thereof is generally sealed.

  The light engine EG fuses a plurality of (four in this example) laser modules 2, a plurality of unit fibers FB2 that respectively transmit the laser beams generated by the laser modules 2, and a plurality of unit fibers FB2. And a combiner 3 for bringing them together. A feed fiber FB3 and a beam switch 4 are connected in series between the combiner 3 and the process fiber FB1, and the laser light collectively output from the combiner 3 is fed to the feed fiber. The light is output into the process fiber FB1 through the FB3 and the beam switch 4. Each laser module 2 is provided with a temperature sensor 6 for measuring the temperature in the laser module 2 and a dew point temperature sensor 7 for measuring the dew point temperature, and the measurement result is sent to the control unit SG. In addition, a temperature sensor 8 that measures the temperature in the housing TK is provided in the housing TK, and the measurement result is sent to the control unit SG.

  The cooling unit RF includes a cooling water supply unit RF1 and a water channel system RF2 piped from the cooling water supply unit RF1 to each laser module 2 and the power supply unit PW. The cooling water supply unit RF1 cools each laser module 2 and the power supply unit PW by flowing cooling water through the water channel system RF2. The cooling water supply unit RF1 maintains and manages the cooling water at 24 ° C. ± 1 ° C., for example.

  Distributor 5 that distributes low dew point dry air supplied from air purge unit 20 via air supply path AR1 to predetermined devices and parts is provided in housing KT. Specifically, the low dew point dry air supplied to the distributor 5 is supplied to each of the plurality of laser modules 2 via a plurality of air branches AR1a branched from the air supply path AR1.

  The laser module 2 includes an excitation light source using a semiconductor laser, a drive circuit, a heat sink, a resonator, and the like (all not shown) and is accommodated in the housing KT. The output of one laser module 2 is about several hundred W (for example, 350 W). Accordingly, since the four laser modules 2 are provided in the example shown in FIG. 2, when the output of each laser module 2 is 350 W, the laser light output from them is collected by the combiner 3 and then processed. It is emitted from the fiber FB1 with an output of 1.4 kW.

  Next, the air purge unit 20 will be described with reference mainly to FIG. The air purge unit 20 includes an activated carbon tank 21, an oil mist filter 22, a low dew point reducing unit 23, and a branching unit 24. A compressor 31 is connected to the input side of the air purge unit 20, and two delivery ports P2a and P2b are provided on the output side.

  The compressor 31 supplies the compressed air A to the input side of the air purge unit 20 through the prefilter 30. The prefilter 30 removes relatively large foreign matters such as oil, foreign matter, oil mist, and water droplets mixed in the compressed air. The compressed air A supplied to the air purge unit 20 passes through the activated carbon tank 21 and the oil mist filter 22 to remove oil, dust, oil mist and the like.

  The compressed air A that has passed through the oil mist filter 22 is branched into two systems by the branching portion 26 via the pressure switch 25. One compressed air A branched into two systems is supplied to the delivery port P2a, and sent out toward the laser processing machine 10 through the air supply path AR2. The other compressed air A branched into the two systems passes through 23 at the dew point reduction unit.

For example, a membrane air dryer (dehumidification filter) can be used as the low dew point reduction unit 23. The membrane type air dryer uses a moisture permeable membrane module 23a in which a hollow fiber membrane such as a porous fluorine-based material having moisture permeability is bundled into a tubular shape as a gas separation membrane module, and the supplied compressed air is supplied to the moisture permeable membrane module 23a. To generate dry air by dehumidification.

More specifically, referring to FIG. 3, when compressed air A1 that has passed through the oil mist filter 22 is supplied from one end side of the moisture permeable membrane module 23a, the compressed air A1 in the compressed air A1 is caused by the difference in water vapor partial pressure inside and outside the membrane. Water vapor (H ₂ O) permeates the membrane and escapes from the cylindrical wall to the outside (see arrow Ab), and becomes dry air A2 from which only moisture has been removed, and is discharged from the other end. The discharged dry air A2 is sent to the distributor 5 of the laser oscillator 1. Since the membrane air dryer is small and light and easy to install, it is suitable for incorporation into equipment such as the air purge unit 20. Moreover, since a power supply is unnecessary, handling is easy.

  By using the above-described moisture permeable membrane module (dehumidifying filter) 23a in the low dew point reducing unit 23 described above, for example, low dew point dry air having a dew point temperature of about −25 ° C. to −5 ° C. is generated. The dew point temperature can be controlled by the pressure of the purge air supplied to the moisture permeable membrane module 23a. The dew point temperature of the purge air is set lower than the temperature of the cooling water (for example, 24 ° C. ± 1 ° C.) in order to prevent condensation.

  The low dew point dry air A2 discharged from the low dew point reducing unit 23 is sent to the sending port P2b via the flow meter 24. The dry air supplied to the sending port P2b is sent to the distributor 5 of the laser oscillator 1 through the air supply path AR1.

  According to the above-described configuration, even when the door (not shown) of the housing KT is opened for maintenance of the laser oscillator 1, the low dew point dry air is supplied directly into the laser module 2 and the power supply unit PW. Therefore, the dew point temperature of the air inside each does not rise rapidly.

  The fiber laser processing apparatus 51 conventionally dehumidifies the purged compressed air that is installed in a factory and supplied to a processing machine or the like through a moisture permeable membrane module as a gas separation membrane module after removing foreign matter by a filter. The dry air having a low dew point obtained by dehumidification is branched into a plurality of supply paths, the dry air having a low dew point is supplied to the laser oscillator 1 through one of the branched supply paths, and the other supply paths in the branched branches The low dew point dry air supplied to the laser oscillator 1 is supplied to each of the plurality of laser modules by the distributor 5, thereby dehumidifying the inside of the laser module 2 and Reduce the dew point.

  According to this dehumidification method, a large flow rate of low dew point dry air can be supplied to the inside of the laser module 2, and the waiting time from the start of dehumidification operation to the output of laser light is short, making the fiber laser processing apparatus very easy to use. Can be good.

  The dehumidifying operation described above is controlled by the control unit SG. For example, the control unit SG controls a pressure switch (valve or the like) 25 installed in a low dew point dry air supply path to reduce the amount of dry air supplied at a low dew point per unit time. You may adjust so that it may become power saving in the range which does not arise. Alternatively, the flow rate may be monitored by a flow meter 24 in the low dew point dry air supply path, and an abnormality may be notified by an alarm or the like when the flow rate falls below a predetermined value.

  In the embodiment of the present invention, the laser module is controlled by controlling the temperature of air in the casing KT by the air conditioner C in parallel with the dehumidifying operation by supplying the low-dew point dry air to the laser module 2 and the power supply unit PW. The temperature of the purge air supplied into 2 is also indirectly controlled. The operation of the air conditioner C is controlled by the control unit SG. In addition to the temperature control by the air conditioner C, the dehumidifying operation of the air conditioner C may be performed.

  By controlling the temperature in the housing KT by the air conditioner C, the purge air can be supplied to the laser module 2 while lowering the temperature of the purge air (or suppressing the temperature rise). Thereby, in addition to the cooling effect by the cooling water supplied to the laser module 2, the laser module 2 can be efficiently cooled by the synergistic effect of the cooling by the purge air in the laser module 2, and the laser oscillation efficiency can be improved. Can be improved.

  The temperature in the housing KT is controlled to a set temperature (for example, 28 ° C.) ± 5 ° C. of the air conditioner C. The temperature of the purge air in the laser module 2 is preferably controlled to a temperature (for example, 28 ° C. ± 5 ° C.) that substantially matches the temperature in the housing KT. The temperature of the purge air in the laser module 2 is controlled to be equal to or lower than the upper limit temperature allowed for the operation of the laser diode in the laser module 2.

  In order to make the outlet temperature of the purge air (the temperature at the discharge port of the air branch AR1a) close to the temperature in the casing KT or substantially coincide with the temperature in the casing KT, the air supply path AR1 and the air branch that propagate the purge air It is preferable that the AR1a is routed to some extent within the housing KT. Further, it is preferable that the air supply path AR1 and the air branch AR1a are routed in the vicinity of the air outlet of the air conditioner C. The purge air is supplied only to the laser module 2 in the housing KT. However, the purge air is also supplied to the parts that require cooling in the housing KT or other parts in the housing KT using piping. May be.

<Example>
Next, an example of the dehumidifying method of the laser oscillator 1 using the fiber laser processing apparatus 51 according to the embodiment of the present invention will be described. At an outside temperature of 40 ° C. and a humidity of 95%, the output of the laser oscillator 1 is 4.2 kW. By supplying 0.5 MPa of purge air to the moisture permeable membrane module 23a, the dew point temperature of the purge air is dehumidified to about −15 ° C. The air conditioner C controls the temperature in the housing KT at a set temperature of 35 ° C. The time transition of the purge air temperature, the temperature inside the housing KT, and the outside air temperature at that time was measured. The measurement results are shown in FIG.

  In FIG. 4, laser oscillation is not performed for about 40 minutes from the start of measurement. At this time, supply of purge air having a dew point temperature of −15 ° C. is also started. Thereafter, laser oscillation is started. At this time, purge air having a dew point temperature of −15 ° C. is continuously supplied, but the air conditioner C is not operated. After about 1 hour and 10 minutes from the start of laser oscillation, purge air having a dew point temperature of −15 ° C. is continuously supplied, and the air conditioner C is operated at a set temperature of 35 ° C. As shown in FIG. 4, when laser oscillation is started, the temperature in the laser module 2 rises to about 50 ° C., and the temperature in the housing KT and the outside air temperature are approximately the same at about 40 ° C. Thereafter, by starting the temperature control of the air conditioner C, the temperature in the housing KT is reduced to about 35 ° C., and the temperature control of the air conditioner C and cooling with cooling water also reduces the temperature of the laser module 2 to about 33 ° C., It can be seen that the temperature inside the casing KT is close.

  FIG. 5 shows the temporal transition of the dew point temperature of the purge air in the laser module 2 when the air conditioner C is used and when it is not used at an outside air temperature of 40 ° C. and a relative humidity of 80%. When the maintenance temperature of the cooling water is 24 ° C. ± 1 ° C., the amount of water vapor in the air in the laser module 2 will not exceed the saturation water vapor amount if the dew point temperature is less than the lower limit temperature of the cooling water of 23 ° C. Condensation does not occur. FIG. 5 shows that when the air conditioner C is used, the time for the dew point temperature to drop to less than 23 ° C. is about 2 minutes, and the dew point temperature decreases most quickly. After that, when the air conditioner C is used, it can be seen that the dew point temperature is stable at about 15 ° C.

  FIG. 6 shows temporal transitions of the side closer to the air conditioner C (air conditioner side temperature), the temperature farther from the air conditioner C (opposite side temperature), and the outside air temperature. From FIG. 6, it can be seen that both the air-conditioner side temperature and the opposite-side temperature are stable after about 2 minutes, and the air-conditioner-side temperature is lower than the opposite-side temperature.

<Dehumidification method of laser oscillator>
Next, an example of the dehumidifying method of the laser oscillator 1 according to the embodiment of the present invention will be described. In step S1, the supply of purge air is started. At the same time, in step S2, the temperature in the housing KT is controlled by the air conditioner C at the set temperature. In step S3, the control unit SG determines whether or not the dew point temperature in the laser module 2 is equal to or lower than a threshold value. The threshold value is set to be lower than the temperature of the cooling water, and may be stored in advance in the memory of the control unit SG. When the dew point temperature in the laser module 2 becomes equal to or lower than the threshold value, the control unit SG controls the pressure switch 25 to decrease the supply amount of the purge air or stop the supply. When the dew point temperature in the laser module 2 becomes higher than the threshold value, the supply amount of purge air may be increased or the supply may be restarted. Thus, by varying the flow rate of the purge air, the effect can be rapidly increased at the time of start-up, and after the temperature and humidity are stabilized, the flow rate of the purge air can be suppressed to save power.

  As described above, according to the embodiment of the present invention, the air conditioner C is installed in the casing KT of the laser oscillator 1 and the purge air is supplied to the laser module 2, and at the same time, the air conditioner C includes the inside of the casing KT. By controlling this temperature, the temperature of the purge air supplied to the laser module 2 can also be indirectly controlled (reduced or suppressed). As a result, condensation in the laser module 2 and the housing KT can be prevented, and high oscillation efficiency can be obtained by cooling with cooling water and purge air.

(Other embodiments)
Although the present invention has been described with reference to embodiments, it should not be understood that the description and drawings that form part of this disclosure limit the present invention. From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art.

  In the embodiment of the present invention, the fiber laser processing apparatus has been described as an example, but the types of the laser oscillator and the laser processing apparatus are not particularly limited. For example, the present invention is also applicable to a DDL processing apparatus having a DDL resonator that oscillates multi-wavelength laser light. In particular, for a DDL processing apparatus, since the LD outputs a relatively high power, the amount of heat generated from the LD is large, and it is effective to apply the laser oscillator according to the embodiment of the present invention.

  Further, the low-dew point dry air branched on the downstream side of the air purge unit 20 may be supplied to the laser processing machine 10.

  Further, the laser processing machine may be welded or other than the one that cuts the workpiece W, and the type of processing is not limited.

  Further, the air purge unit 20 may be integrally accommodated in the laser oscillator 1.

  As described above, the present invention naturally includes various embodiments not described herein. Therefore, the technical scope of the present invention is defined only by the invention specifying matters according to the scope of claims reasonable from the above description.

DESCRIPTION OF SYMBOLS 1 ... Laser oscillator 2 ... Laser module 3 ... Combiner 4 ... Beam switch 5 ... Distributor 6, 8 ... Temperature sensor 7 ... Dew point temperature sensor 10 ... Laser processing machine 12 ... Collimator lens 13 ... Collimator unit 14 ... Bend mirror 15 ... Condensing Lens 16 ... Laser head 18 ... Processing table 20 ... Air purge unit 21 ... Activated carbon tank 22 ... Oil mist filter 23 ... Low dew point part 23a ... Moisture permeable membrane module 24 ... Flow meter 25 ... Pressure switch 26 ... Branch part 51 ... Fiber laser Processing equipment A, A1 ... Compressed air A2 ... Dry air AR1 ... Air supply path AR1a, AR1b ... Air branch C ... Air conditioner EG ... Optical engine FB1 ... Process fiber FB2 ... Unit fiber FB3 ... Feed fiber KT ... Housing L ... Laser light P1 ... Supply port P2a, P2b ... Delivery port PW ... Power supply unit PW1 ... Housing RF ... Cooling unit RF1 ... Cooling water supply unit RF2 ... Water channel system SG ... Control unit SG1 ... Housing t ... Dehumidification time W ... Workpiece

Claims (7)

A laser module that houses a laser diode that oscillates the laser;
A housing for housing the laser module;
A cooling path connected to the laser module;
An air purge unit that generates dry air with a low dew point from compressed compressed air supplied from the outside and supplies the dry air to the laser module via an air supply path;
And air conditioning to control the temperature of the housing to the air purge unit according to the dry-air supply and in parallel with the casing by Ri before Symbol dry air to control the temperature of the body has a blower opening,
With
The laser oscillator, wherein the air supply path is routed in the vicinity of the blower opening.   2. The laser oscillator according to claim 1, wherein the temperature in the housing is controlled so that the air conditioner is equal to or lower than an upper limit temperature allowed by the laser diode.   3. The laser oscillator according to claim 1, wherein a dew point temperature of the dry air is lower than a set temperature of the cooling path.   4. The laser oscillator according to claim 1, wherein a dew point temperature of the dry air is −25 ° C. to −5 ° C. 5. A dew point temperature sensor for measuring a dew point temperature of purge air in the laser module;
5. The laser oscillator according to claim 1, wherein when the dew point temperature of the purge air in the laser module becomes a threshold value or less, the supply amount of the purge air is reduced. The laser oscillator according to any one of claims 1 to 5,
A transmission fiber for transmitting laser light oscillated by the laser oscillator;
A laser processing machine for condensing the laser beam transmitted by the transmission fiber and processing the workpiece;
A laser processing apparatus comprising: A dehumidifying method for a laser oscillator according to any one of claims 1 to 5,
A dry air supply step in which the air purge unit generates dry air with a low dew point from the purged compressed air, and supplies the generated dry air to the laser module via the air supply path;
In parallel with the dry air supply step, a dry air temperature control step for controlling the temperature of the dry air passing through the air supply path routed at least in the vicinity of the air blowing port by controlling the temperature in the housing by the air conditioner; ,
A method for dehumidifying a laser oscillator, comprising:

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