JP2014104479A - Fiber laser beam machining device, and fiber disconnection detection method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fiber laser beam machining device and a fiber disconnection detection method, that can detect disconnection of an optical fiber from a laser oscillator module to a laser beam machining head.SOLUTION: A fiber laser beam machining device includes: a plurality of laser oscillator modules 13A, 13B, ... including a plurality of pumping LD groups 19 with a plurality of pumping LDs 15A, 15B, ... and a fiber laser resonator 21 connecting the plurality of pumping LD groups 19; a feeding fiber 7 connecting the respective laser oscillator modules 13A, 13B, ...; a process fiber 9 connected with the feeding fiber 7 through a fiber coupler 11; and a laser beam machining head 5 optically connected with the process fiber 9. The respective pumping LD groups 19 include disconnection detection LDs 27, respectively. The laser beam machining head 5 includes a disconnection detection PD 29 for detecting a laser beam for detection, which is oscillated by the respective disconnection detection LDs 27.

Description

  The present invention relates to a fiber laser processing machine provided with a fiber laser oscillator and a disconnection detection method for detecting disconnection of an optical fiber in the fiber laser processing machine, and more specifically, to a plurality of laser oscillator modules that oscillate laser light. A fiber laser processing machine having a laser processing head including a disconnection detection PD for detecting a detection laser beam oscillated from the disconnection detection LD, and the disconnection detection LD, The present invention relates to a disconnection detection method for detecting disconnection of an optical fiber using a disconnection detection PD.

  As is known, a fiber laser processing machine has a configuration including a fiber laser oscillator and a laser processing head, a feeding fiber is connected to the fiber laser oscillator, and a process fiber is connected to the laser processing head. Connected.

  The feeding fiber and the process fiber are connected via a fiber coupler. The fiber laser oscillator includes a plurality of laser oscillator modules connected in parallel. The laser oscillator module includes a plurality of excitation LDs and a fiber laser resonator.

  And since the optical system from each said excitation LD to a feeding fiber is connected monolithically (monolithic), it is difficult to provide the structure for detecting the disconnection of an optical fiber in the said optical system. In a laser processing machine, in a configuration using an optical fiber, means for detecting disconnection of the optical fiber is provided (for example, see Patent Documents 1 and 2).

JP 61-249002 A JP 2012-24774 A

  The configurations described in Patent Documents 1 and 2 are configured to detect disconnection of an optical fiber provided between a laser oscillator and a laser processing head, and the optical fiber includes a separate optical fiber or conductor for detecting disconnection. It is a configuration. In the above configuration, it is possible to detect disconnection of the optical fiber disposed between the laser oscillator and the laser processing head. However, in the fiber laser processing machine, the configuration from the plurality of pumping LDs to the feeding fiber provided in the laser oscillator is connected monolithically, so the configuration as described in Patent Documents 1 and 2 should be adopted. Is difficult.

  The present invention has been made in view of the above-described problems, and includes a plurality of pumping LD groups each including a plurality of pumping LDs, and a fiber laser resonator connected to the plurality of pumping LD groups. A plurality of laser oscillator modules; a feeding fiber connected to each of the laser oscillator modules; a process fiber connected to the feeding fiber via a fiber coupler; a laser processing head optically connected to the process fiber; Each of the excitation LD groups is provided with a disconnection detection LD, and a disconnection detection PD for detecting the detection laser light oscillated from each of the disconnection detection LDs is provided. It is provided in the laser processing head.

  Further, in the fiber laser processing machine, each detection laser beam oscillated from each disconnection detection LD provided in each excitation LD group has a different wavelength.

  In the fiber laser processing machine, a laser beam input from the process fiber is provided with a bend mirror that bends in a direction of a processing nozzle provided in the laser processing head, and each detection laser beam transmitted through the bend mirror is transmitted. It comprises a diffracting means for partially diffracting, and a plurality of disconnection detecting PDs for detecting each wavelength diffracted by the diffracting means.

  Also, a disconnection detection method using the fiber laser processing machine, wherein the detection laser light generated by exciting each disconnection detection LD provided in each excitation LD group individually is detected as a disconnection detection PD. By detecting by the above, the presence or absence of disconnection of the optical fiber from each excitation LD group to the laser processing head is detected.

  Further, a plurality of laser oscillator modules each including a plurality of excitation LD groups including a plurality of excitation LDs, and a fiber laser resonator connected to the plurality of excitation LD groups, and the laser oscillator modules are connected to each other. A laser processing machine comprising: a feeding fiber, a process fiber connected to the feeding fiber via a fiber coupler, and a laser processing head optically connected to the process fiber, each laser oscillator The laser processing head is provided with a power sensor for detecting disconnection for detecting laser light individually oscillated from the module.

  According to the present invention, each of the plurality of excitation LD groups including the plurality of excitation LDs includes the disconnection detection LD, and the processing head includes the disconnection detection PD. In the optical system from the LD group for laser to the laser processing head, if a break occurs in the optical fiber, the break can be easily detected.

It is explanatory drawing which showed notionally and schematically the structure of the laser processing machine which concerns on embodiment of this invention. It is explanatory drawing which showed notionally and schematically the structure of the laser processing machine which concerns on 2nd Embodiment.

  Hereinafter, the configuration of the laser processing machine according to the embodiment of the present invention will be described with reference to the drawings. The overall configuration of the fiber laser processing machine including the fiber laser oscillator is a well-known configuration. The configuration will be described conceptually and schematically.

  Referring to FIG. 1, a fiber laser processing machine 1 according to an embodiment of the present invention includes a fiber laser oscillator 3 and a laser processing head 5. The fiber laser oscillator 3 and the laser processing head 5 are optically connected via a feeding fiber 7 and a process fiber 9. The feeding fiber 7 and the process fiber 9 are optically connected via a fiber coupler 11 in which a collimator lens and a condenser lens are incorporated.

  The fiber laser oscillator 3 includes a plurality of laser oscillator modules 13A, 13B,. Each of the laser oscillator modules 13A, 13B,... Includes a pumping LD group 19 in which a plurality of pumping LDs 15A, 15B,. A fiber laser resonator 21 is connected to the pumping LD group 19. That is, each laser oscillator module 13A, 13B,... Has a configuration including the excitation LD group 19 and the fiber laser resonator 21. The fiber laser oscillator 3 has a configuration in which the beam combiner 23 is optically connected in parallel.

  One end of the feeding fiber 7 is connected to the beam combiner 23, and the other end is connected to the fiber coupler 11. One end of the process fiber 9 is connected to the fiber coupler 11, and the other end is connected to the laser processing head 5. The laser processing head 5 includes a collimator lens CL that collimates the laser light emitted from the emission end of the process fiber 9 and condenses the laser light to irradiate the workpiece W. It has. Further, the laser processing head 5 includes a bend mirror 25 that bends the laser light transmitted through the collimator lens CL in the direction of the condenser lens FL.

  In the configuration described above, in order to detect disconnection (including damage) of the optical fiber in the optical system from each excitation LD group 19 in the fiber laser oscillator 3 to the laser processing head 5, the excitation LD in each excitation LD group 19 is detected. A disconnection detection LD 27 is connected to the combiner 17. The wavelength of the laser light oscillated from the disconnection detection LD 27 is different from the wavelength of the laser light oscillated from the excitation LDs 15A, 15B,. On the back side of the bend mirror 25 in the laser processing head 5, a disconnection detection PD 29 as a light receiving element that detects a part of transmitted light of the detection laser light oscillated from each disconnection detection LD 27. Is provided.

  With the above-described configuration, the disconnection detection LD 27 connected to each excitation LD group 19 is individually excited to detect the detection laser light oscillated and detected by the disconnection detection PD. The presence or absence of disconnection of the optical fiber between the laser beam and the laser processing head 5 can be detected. Here, for example, when the disconnection detecting LD 27 in the laser oscillator module 13A is excited and the detection laser light of the disconnection detecting LD is detected by the disconnection detecting PD 29, the laser oscillator module 13A and the laser processing head 5 are connected. The optical fiber can be detected as normal.

  Similarly, the disconnection detecting LD 27 in each laser oscillator module 13B, 13C,... Is sequentially excited, and the detection laser light is detected by the disconnect detection PD 29, so that each laser oscillator module 13B, 13C,. The presence or absence of disconnection of the optical fiber between the head 5 can be detected.

  As already understood from the above description, the laser oscillator module 13C and the laser processing head are detected despite the fact that no disconnection has occurred in the optical fiber between the laser oscillator modules 13A and 13B and the laser processing head 5, for example. 5 is detected as being broken, the laser oscillator module 13C can be detected as being damaged. Therefore, in this case, the fiber laser oscillator 3 can be repaired by replacing the laser oscillator module 13C with a new laser oscillator module.

  The probability that all the disconnection detecting LDs 27 in all the laser oscillator modules 13A, 13B,... Are defective at the same time is extremely small. Therefore, even if each disconnection detecting LD 27 in each of the laser oscillator modules 13A, 13B,... Is sequentially excited, if the detection laser beam cannot be detected by the disconnection detecting PD 29, the fee is detected. It is possible to detect that there is a failure such as disconnection in a part or the whole of the optical system in the ding fiber 7, the fiber coupler 11, the process fiber 9, or the laser processing head 5.

  FIG. 2 shows a second embodiment of the present invention. In the second embodiment, the wavelength of the detection laser light oscillated in each disconnection detection LD in each laser oscillator module 13A, 13B,... Is set to a different wavelength. A diffraction grating or prism is provided as an example of the diffracting means 31 that diffracts a part of each detection laser beam transmitted through the bend mirror 25 in the laser processing head 5. Further, a photodiode array 33 is provided for detecting the detection laser light of each wavelength diffracted by the diffraction means 31.

  With the above configuration, when there is detection laser light that cannot be detected in the photodiode array 33, the laser oscillator module provided with the disconnection detection LD 27 that oscillates the detection laser light that cannot be detected has failed. Can be detected as having occurred. In addition, when no detection laser light can be detected by the photodiode array 33, it is assumed that a disconnection has occurred in a part or a plurality of positions of the feeding fiber 7, the fiber coupler 11, the process fiber 9, or the laser processing head 5. It can be detected.

  By the way, the present invention is not limited to the above-described embodiment, and can be implemented in other forms by making appropriate changes. For example, instead of the disconnection detection PD 29, a configuration including a power sensor may be employed. In this case, for example, each laser oscillator module 13A, 13B,..., Excitation of each excitation LD 15A, 15B,. .. Is performed for each laser oscillation to detect whether a failure has occurred in each of the laser oscillator modules 13A, 13B,..., For example, a failure has occurred in the feeding fiber 7 or the like. An effect similar to that of the form can be obtained.

  The laser output is detected by the power sensor each time laser oscillation is individually performed by each laser oscillator module 13A, 13B,. Then, the detection value by the power sensor is compared with the set value obtained in advance by experiments or the like and stored in the set value memory by the comparison means. As described above, when the detection value is equal to or smaller than the set value as a result of comparison by the comparison means, for example, it can be detected that the excitation LDs 15A, 15B,. Therefore, this can be dealt with by replacing the corresponding laser oscillator module with a new laser oscillator module.

  In addition, each excitation LD 15A, 15B,... In each laser oscillator module 13A, 13B,... Can be individually excited so that each excitation LD 15A, 15B,. Is possible. In this case, the failure of each of the excitation LDs 15A, 15B,... Can be detected.

DESCRIPTION OF SYMBOLS 1 Fiber laser processing machine 3 Fiber laser oscillator 5 Laser processing head 7 Feeding fiber 9 Process fiber 11 Fiber coupler 13A, 13B, ... Laser oscillator module 15A, 15B, ... LD for excitation
19 LD group for excitation 21 Fiber laser resonator 25 Bend mirror 27 LD for disconnection detection
29 PD for disconnection detection
31 Diffraction means 33 Photodiode array

Claims (5)

A plurality of laser oscillator modules each including a plurality of pumping LD groups each including a plurality of pumping LDs, and a fiber laser resonator connected to the plurality of pumping LD groups;
A feeding fiber connected to each of the laser oscillator modules, and
A process fiber connected to the feeding fiber via a fiber coupler;
A laser processing machine comprising a laser processing head optically connected to the process fiber,
Each excitation LD group includes a disconnection detection LD, and the laser processing head includes a disconnection detection PD for detecting a detection laser beam oscillated from each disconnection detection LD. A featured fiber laser processing machine.   2. The fiber laser processing machine according to claim 1, wherein each of the detection laser beams oscillated from each disconnection detection LD provided in each of the excitation LD groups has a different wavelength.   The fiber laser processing machine according to claim 2, further comprising a bend mirror that bends the laser light input from the process fiber in a direction of a processing nozzle provided in the laser processing head, and for each detection that has passed through the bend mirror. A fiber laser processing machine comprising a diffracting means for diffracting a part of a laser beam, and comprising a plurality of disconnection detecting PDs for detecting each wavelength diffracted by the diffracting means.   A disconnection detection method using the fiber laser processing machine according to claim 1, wherein the detection laser light generated by exciting each disconnection detection LD provided in each excitation LD group is disconnected. A disconnection detection method characterized by detecting the presence or absence of disconnection of an optical fiber from each excitation LD group to a laser processing head by detecting with a detection PD. A plurality of laser oscillator modules each including a plurality of pumping LD groups each including a plurality of pumping LDs, and a fiber laser resonator connected to the plurality of pumping LD groups;
A feeding fiber connected to each of the laser oscillator modules, and
A process fiber connected to the feeding fiber via a fiber coupler;
A laser processing machine comprising a laser processing head optically connected to the process fiber,
A fiber laser processing machine, wherein the laser processing head includes a disconnection detection power sensor for detecting laser light individually oscillated from each laser oscillator module.

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