Laser device and transmission fiber connection adjustment method

Abstract

To provide a laser device and a transmission fiber connection adjustment method that can more easily adjust the angle of incidence of laser light incident on a transmission fiber to an appropriate condition.SOLUTION: The laser device according to the present disclosure includes: a laser oscillator that emits laser light; a focusing lens that focuses the laser light emitted from the laser oscillator; a transmission fiber that transmits the laser light focused by the focusing lens; and an incident-side angle adjustment unit that adjusts an angle of a central axis of the transmission fiber relative to an optical axis of the laser light focused by the focusing lens so that a spot diameter of the laser light emitted from the transmission fiber is equal to or smaller than a reference size.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a laser device capable of monitoring the incident position and incident angle onto a transmission fiber and a transmission fiber connection adjustment method. [Background technology]

[0002] In laser processing, laser light emitted from a laser light source is guided through a transmission fiber to a processing head and is then irradiated onto a workpiece.

[0003] The core of the transmission fiber has individual differences in the center position and the angle of deviation of the central axis. Therefore, the characteristics of the laser light emitted from the processing head change every time the attached transmission fiber is changed. Therefore, when replacing the transmission fiber, it is necessary to find the conditions under which the laser light characteristics for each individual fiber will produce the desired results, such as by adjusting the optical components inside the processing head. This also prolongs the time (downtime) required for restoration work, including the replacement of the transmission fiber.

[0004] Patent Document 1 proposes a method for facilitating the replacement of a transmission fiber by monitoring the incident end face of the transmission fiber and, based on the results, adjusting the focal point of the laser light to the center of the incident end face. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Unexamined Patent Publication No. 7-104147 Summary of the Invention [Problem to be solved by the invention]

[0006] However, Patent Document 1 does not take into consideration the angle of the laser light incident on the transmission fiber. The incident angle on the transmission fiber significantly affects the beam quality of the laser light emitted from the transmission fiber. Therefore, if the incident angle changes after replacing the transmission fiber, there is a risk that the beam quality will deteriorate.

[0007] Therefore, the present disclosure provides a laser device and a transmission fiber connection adjustment method that can more easily adjust the incident angle of laser light incident on a transmission fiber to an appropriate condition. [Means for solving the problem]

[0008] The laser device according to the present disclosure includes a laser oscillator that emits laser light, a focusing lens that focuses the laser light emitted from the laser oscillator, a transmission fiber that transmits the laser light focused by the focusing lens, and an incident-side angle adjustment unit that adjusts the angle of the central axis of the transmission fiber relative to the optical axis of the laser light focused by the focusing lens so that the spot diameter of the laser light emitted from the transmission fiber is equal to or smaller than a reference size.

[0009] The transmission fiber connection adjustment method according to the present disclosure includes a laser oscillator that emits laser light, a focusing lens that focuses the laser light emitted from the laser oscillator, and a transmission fiber that transmits the laser light focused by the focusing lens, and adjusts the angle of the central axis of the transmission fiber with respect to the optical axis of the laser light focused by the focusing lens so that the spot diameter of the laser light emitted from the transmission fiber is equal to or smaller than a reference size. [Effects of the Invention]

[0010] The laser device and transmission fiber connection adjustment method according to the present disclosure can more easily adjust the incident angle of laser light incident on the transmission fiber to an appropriate condition, which makes it easier to replace the transmission fiber and perform the adjustment work involved, reducing downtime and the burden on the operator. [Brief explanation of the drawings]

[0011] [Figure 1] Schematic diagram of a laser device according to an embodiment [Figure 2] Conceptual diagram for explaining the first embodiment [Figure 3] Conceptual diagram of angle adjustment section [Figure 4] Cross section of a transmission fiber with individual variations in the core center [Figure 5] Conceptual diagram explaining core-centered individual difference detection [Figure 6] Conceptual diagram explaining transmission fibers with individual differences in the deviation angle of the core central axis [Figure 7] Conceptual diagram explaining adjustment of the incident side angle adjustment unit [Figure 8] Conceptual diagram explaining adjustment of the output side angle adjustment unit [Figure 9] Diagram showing the connection adjustment procedure after replacing the transmission fiber [Figure 10] Conceptual diagram for explaining the second embodiment DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of a laser device according to the present disclosure will be described with reference to the drawings. Note that all of the embodiments disclosed below are merely examples, and no limitations are intended to be placed on the laser device according to the present disclosure. For example, the laser device according to the present disclosure will be described assuming that it uses a direct diode laser, but it is not limited to this, and a fiber laser, a disk laser, or the like may also be used.

[0013] Furthermore, in the embodiments disclosed below, unnecessary detailed explanations may be omitted. For example, detailed explanations of well-known matters or redundant explanations of substantially identical configurations may be omitted. This is to avoid unnecessary redundancy in the explanations and to facilitate understanding by those skilled in the art.

[0014] [Embodiment 1] Fig. 1 is an external view of a laser device according to an embodiment. As shown in Fig. 1, the laser device 1 includes a laser oscillator 10, a transmission fiber 50, a processing head 60, and a control unit 80. The laser oscillator 10 is, for example, a direct diode laser that uses wavelength combining technology, and includes multiple laser modules 20, a beam combiner 30, and a focusing unit 40.

[0015] The laser oscillator 10 combines laser beams emitted from a plurality of laser modules 20 into one laser beam 3 using a beam combiner 30. The laser module 20 is composed of a plurality of laser diodes, for example, a semiconductor laser array.

[0016] The focusing unit 40 focuses the laser light 3 combined by the beam combiner 30. By configuring the laser oscillator 10 in this way, a high-output laser device 1 can be obtained in which the output of the laser light 3 exceeds several kW.

[0017] The transmission fiber 50 transmits the laser light 3 focused by the focusing unit 40 to the processing head 60. The processing head 60 irradiates the laser light 3 transmitted by the transmission fiber 50 onto the object 2.

[0018] 2 is a conceptual diagram illustrating the first embodiment, and also shows the direction in which the laser light 3 travels.

[0019] 2, the beam combiner 30 has a mirror 31. The mirror 31 reflects the combined laser light 3 to guide the laser light 3 to the light collecting unit 40.

[0020] The light collecting unit 40 includes a light collecting housing 49 , an incident side holding portion 42 , and an incident side angle adjusting portion 44 .

[0021] The condenser housing 49 has an incident-side condenser lens 41 and a condenser lens adjustment unit 43. The incident-side condenser lens 41 condenses the laser light 3 reflected by the mirror 31 toward the transmission fiber 50. The condenser lens adjustment unit 43 adjusts the position of the incident-side condenser lens 41 in the X-axis, Y-axis, and Z-axis directions. The condenser lens adjustment unit 43 can adjust the condensing position of the laser light 3 (the incident position into the transmission fiber 50) by changing the position of the incident-side condenser lens 41. The adjustment method of the condenser lens adjustment unit 43 will be described in detail later.

[0022] The incident side holding part 42 has a cavity for inserting the transmission fiber 50, and has a function of holding the incident side insertion part 55 of the transmission fiber 50. In addition, the incident side insertion part 55 of the transmission fiber 50 is detachable from the incident side holding part 42.

[0023] The incident-side angle adjuster 44 adjusts the inclination of the incident-side insertion section 55 side of the transmission fiber 50. The structure and adjustment method of the incident-side angle adjuster 44 will be described in detail later.

[0024] The transmission fiber 50 has a core 52, a clad 53, an incident-side quartz block 51, and an output-side quartz block 54. The core 52 and the clad 53 are approximately cylindrical, with the core 52 being surrounded by the clad 53. The laser light 3 that enters the core 52 is transmitted to the processing head 60. The incident-side quartz block 51 and the output-side quartz block 54 are provided in contact with an end face (incident end face 57) of the transmission fiber 50 on the incident side and an end face (output end face 58) of the transmission fiber 50 on the output side.

[0025] The processing head 60 has a head housing 69 , an output side holding portion 65 , and an output side angle adjusting portion 64 .

[0026] The head housing 69 has a connection end surface 69 a into which the output side insertion portion 56 of the transmission fiber 50 is inserted, and includes a partial reflection mirror 61 , a photodetector 62 , a mirror 63 , a collimator lens 66 , and an output side condenser lens 67 .

[0027] The partial reflection mirror 61 reflects a portion, for example, 0.01%, of the laser light 3 emitted from the transmission fiber 50, and transmits the remaining laser light 3.

[0028] The photodetector 62 receives the laser light 3b reflected by the partial reflection mirror 61. The photodetector 62 is, for example, a CCD camera, and outputs an electrical signal indicating the intensity, shape, etc. of the received light.

[0029] The mirror 63 reflects the laser light 3 that has passed through the partial reflection mirror 61 toward the irradiation port of the processing head 60.

[0030] The collimating lens 66 collimates (uniformizes) the laser light 3 reflected by the mirror 63. Furthermore, the output-side condensing lens 67 condenses the laser light collimated by the collimating lens 66 toward the object 2.

[0031] The output side holding part 65 has a cavity for inserting the transmission fiber 50, and holds the output side insertion part 56 of the transmission fiber 50. The output side insertion part 56 of the transmission fiber 50 is detachable from the output side holding part 65. The output side angle adjusting part 64 adjusts the tilt of the output side insertion part 56 side of the transmission fiber 50. The output side angle adjusting part 64 has a structure similar to that of the input side angle adjusting part 44. The method of adjusting the output side angle adjusting part 64 will be described in detail later.

[0032] The control unit 80 compares the electrical signal output from the photodetector 62 with settings (a threshold W and a reference spot size 81, which will be described later) previously set by the operator, and outputs the comparison result. Based on the comparison result output by the control unit 80, the operator adjusts the condenser lens adjustment unit 43, the incident side angle adjustment unit 44, and the output side angle adjustment unit 64, and adjusts the connection of the transmission fiber 50. The connection adjustment procedure for the transmission fiber 50 will be described in detail later.

[0033] Figure 3 is a conceptual diagram of the incident-side angle adjustment unit. Figure 3(a) is a side view of the angle adjustment unit, and Figure 3(b) is a plan view of the angle adjustment unit. The incident-side angle adjustment unit 44 is installed between the condenser housing 49 and the incident-side holder 42, and adjusts the angle of the central axis 4 of the transmission fiber 50 relative to the optical axis 3a of the laser light 3 condensed by the incident-side condenser lens 41. The incident-side angle adjustment unit 44 has an incident-side angle adjustment plate 48, an adjuster 45, and an O-ring 46.

[0034] The incident-side angle adjusting plate 48 has a cavity for inserting a transmission fiber 50 (fiber insertion portion 47).

[0035] The adjusters 45 are, for example, screws, and three of them (45a, 45b, 45c) are provided on the incident-side angle adjustment plate 48. The adjusters 45 adjust the angle of the incident-side angle adjustment plate 48 by changing the amount of tightening of the adjusters. Here, the three adjusters 45 may be configured such that two are movable and one is immovable. For example, if adjuster 45c is immovable, adjuster 45c serves as a fulcrum, and the angle of the incident-side angle adjustment plate 48 is adjusted by adjusting the amount of tightening of the other two adjusters 45a and 45b.

[0036] The O-ring 46 has a repulsive force and is provided to seal the gap between the incident side adjustment plate 48 and the light-collecting housing 49. The angle of the incident side angle adjustment plate 48 is maintained by the adjuster 45 and the O-ring 46.

[0037] The output-side angle adjuster 64 is installed between the head housing 69 and the output-side holder 65, and adjusts the angle of the output end face 58 of the transmission fiber 50 relative to the connection end face 69a of the transmission fiber 50 in the head housing 69. The structure of the output-side angle adjuster 64 is similar to that of the input-side angle adjuster 44, and therefore a description thereof will be omitted.

[0038] Here, it is preferable that the incident-side angle adjusting unit 44 is inserted so as to hold the incident end face 57 of the transmission fiber 50. Similarly, it is preferable that the output-side angle adjusting unit 64 is inserted so as to hold the output end face 58 of the transmission fiber 50. This is to improve the accuracy of adjustment by the incident-side angle adjusting unit 44 and the output-side angle adjusting unit 64.

[0039] (Individual differences in transmission fibers) Figure 4 is a cross-sectional view of a transmission fiber having individual differences in the core center. Figure 4(a) is a cross-sectional view on the XY plane of the transmission fiber 50a before replacement. Figure 4(b) is a cross-sectional view on the XY plane of the transmission fiber 50b after replacement. The term "deviation" used in the following description refers to the difference when comparing the transmission fiber 50a before replacement and the transmission fiber 50b after replacement. The gray circle indicates the spot (incident spot 21) of the laser light 3 on the incident end face 57 of the transmission fiber 50.

[0040] 4(a) and 4(b), the position of the center of the core 52 (core center C) relative to the center O of the transmission fiber 50 at the incident end face 57 is different. This causes the center P' of the incident spot 21 to be displaced from the core center C. In this case, as shown in FIG. 4(b), in the replaced transmission fiber 50b, there is a high possibility that part of the laser light 3 focused by the incident-side focusing lens 41 will be incident on the cladding 53. If the laser light 3 is incident on the cladding 53, this may result in a decrease in the output of the laser light 3 emitted from the transmission fiber and localized heat generation. In particular, if damage caused by heat accumulates, it may lead to breakage of the transmission fiber 50.

[0041] As described above, due to individual differences in the core center C, the conditions appropriate for the transmission fiber 50a before replacement, i.e., the position of the incident-side focusing lens 41 on the XYZ coordinate system, may become inappropriate for the replaced transmission fiber 50. Therefore, the worker detects the deviation of the core center C using a method described later, and makes adjustments so that the laser light 3 is also appropriately incident on the replaced transmission fiber 50b.

[0042] FIG. 5 is a conceptual diagram illustrating the detection of individual differences at the core center.

[0043] The deviation of the center position C of the core 52 on the incident end face 57 can be detected by monitoring the emitted light intensity S output from the photodetector 62. Here, the control unit 80 presets a threshold W, which is the emission intensity when the incident position of the laser light 3 on the core 52 is accurate. When the laser light 3 enters the cladding 53, the output of the laser light 3 emitted from the exit end face 58 decreases. Therefore, if the emission intensity is below the threshold W, it is determined that the incident position of the laser light 3 on the core 52 has shifted. The incidence position is adjusted by moving the incident-side collecting lens 41, that is, by moving the collecting lens adjustment unit 43 in the X, Y, and Z directions, so that the emission intensity is equal to or greater than the threshold W.

[0044] Specifically, when it is determined that the output light intensity S output by the photodetector 62 is equal to or less than the threshold value W, the condenser lens adjuster 43 is first moved in the X-axis direction. The adjustment in the X-axis direction is completed at the position where the output light intensity S is at its maximum (FIG. 5(a)). Next, the condenser lens adjuster 43 is moved in the Y-axis direction, and the adjustment in the Y-axis direction is completed at the position where the output light intensity S is at its maximum (FIG. 5(b)). Finally, the condenser lens adjuster 43 is moved in the Z-axis direction, and the adjustment in the Z-axis direction is completed at the position where the output light intensity S is equal to or greater than the threshold value W (FIG. 5(c)). For example, when the condenser lens adjuster 43 is moved +1 μm at a time from the initial position, if the output light intensity S is on an upward trend, the condenser lens adjuster 43 is further moved +1 μm. This process is repeated, and the adjustment is completed at a position moved -1 μm from the point where the output light intensity S starts to decrease, which is the optimal position. On the other hand, if the emitted light intensity S tends to decrease when moved +1 μm from the initial position, it is determined that the peak of the emitted light intensity is on the negative side, and the adjustment is made -1 μm (returning to the original position). If the emitted light intensity S tends to increase when moved further -1 μm at a time, the adjustment unit is moved another -1 μm. This process is repeated, and the adjustment unit is moved in the same direction until the emitted light intensity S starts to decrease. This process is repeated, and the position moved +1 μm from the point where the decreasing trend starts is designated as the optimal position, and the adjustment is completed. The optimal position is the position where the emitted light intensity tends to decrease whether moved +1 μm or -1 μm, with the optimal position being the origin. Note that this embodiment discloses a method of moving the lens 1 μm at a time, but the adjustment amount can be selected as long as it is 1 to 5% of the core diameter. Furthermore, the focusing lens adjustment unit 43 performs adjustment when it detects a change in the output light intensity S of 0.1% or more relative to the output from the laser oscillator. This enables adjustment to eliminate negligible increases or decreases in the emitted light intensity S.

[0045] Generally, a transmission fiber has a different deflection angle θ between the input end face 57 and the output end face 58. arg FIG. 6 is a conceptual diagram illustrating a transmission fiber having individual differences in the deflection angle of the central axis of the core. FIG. 6(a) is a cross-sectional view of the YZ plane of a transmission fiber 50a before replacement. FIG. 6(b) is a cross-sectional view of a transmission fiber 50a having an incident end face 57 with a deflection angle θ arg 6(c) is a cross-sectional view of the YZ plane of the transmission fiber 50b after replacement, which has a deflection angle θarg 6(a) and 6(b), the transmission fiber 50a before replacement has a deflection angle θ arg (negligibly small), and the transmission fiber 50b after replacement has a deflection angle θ arg and the output end face 58 has a deflection angle θ arg As shown in FIG. 6, a transmission fiber 50 has a core 52, and the laser light 3 is transmitted through the core 52. In the description according to the present disclosure, the deflection angle θ arg is the angle between the central axis 4 of the transmission fiber and the central axis 5 of the core (see FIG. 6(b)). Here, the incident angle θ in The divergence angle θ is the angle formed by the central axis 4 of the transmission fiber, particularly the central axis 5 of the core near the incident end face 57, and the outermost ray of the laser light 3 incident on the transmission fiber 50. out This refers to the angle formed by the optical axis 3 a of the laser light 3 emitted from the transmission fiber 50 and the outermost ray of the laser light 3 emitted from the transmission fiber 50 .

[0046] As shown in FIG. 6(a), the transmission fiber 50a before replacement has a deflection angle θ arg , the optical axis 3a is coaxial with the central axis 4 of the transmission fiber and the central axis 5 of the core. In this case, the laser light 3 is incident on the transmission fiber 50a at an incident angle θ in When the light is incident at an incident angle θ in The divergence angle θ is equal to out On the other hand, as shown in FIG. 6(b), the transmission fiber 50b after replacement emits light at an angle of deviation θ arg In other words, the optical axis 3a of the laser light 3 incident on the transmission fiber 50b is coaxial with the central axis 4 of the transmission fiber, but the optical axis 3a is not coaxial with the central axis 5 of the core. In this case, the laser light 3 is incident on the transmission fiber 50b at an incident angle θ in Even if the light is incident at a divergence angle θ out is the incident angle θ in and argument θ argIn other words, by replacing the transmission fiber 50, the divergence angle θ out Here, the beam quality depends on the diameter of the core 52 and the divergence angle θ out The smaller the value, the better the beam quality. out Therefore, the smaller the deviation angle θ at the entrance end face 57 of the transmission fiber 50, the better the beam quality. arg The divergence angle θ of the laser light 3 emitted from the transmission fiber 50 out As the divergence angle θ increases, the beam quality deteriorates. out is the incident angle θ in and the angle θ arg Therefore, it is difficult to improve the beam quality even if the laser light 3 after being emitted from the transmission fiber 50 is adjusted by an optical system.

[0047] The transmission fiber 50b after replacement shown in FIG. 6(c) has an incident end face 57 with a deflection angle θ arg and the output end surface 58 has a deflection angle θ arg As mentioned above, the divergence angle θ out is the incident angle θ in and the angle θ arg Therefore, the deflection angle θ arg The transmission fiber 50b has a deflection angle θ arg However, the optical axis 3a of the laser light 3 emitted from the transmission fiber 50b is angled with respect to the central axis 4 of the transmission fiber 50b.

[0048] As described above, the deflection angle θ arg Therefore, the conditions appropriate for the transmission fiber 50a before replacement, i.e., the angles of the incident-side angle adjuster 44 and the output-side angle adjuster 64, may become inappropriate for the transmission fiber 50b after replacement. arg By detecting the deviation and adjusting the angles of the incident-side angle adjuster 44 and the output-side angle adjuster 64, the laser light 3 is adjusted so as to be properly incident on the replaced transmission fiber 50b as well.

[0049] In the above explanation, the transmission fiber 50a before replacement has a deflection angle θ arg However, this is not limited to this example. arg In addition, each transmission fiber 50 may have a deflection angle θ arg Needless to say, the sizes are different.

[0050] Fig. 7 is a conceptual diagram illustrating adjustment of the incident side angle adjuster. Fig. 7(a) is a conceptual diagram of the laser device before adjustment of the incident side angle adjuster 44. Fig. 7(b) is the output result of the control unit 80 before adjustment of the incident side angle adjuster 44. Fig. 7(c) is a conceptual diagram of the laser device after adjustment of the incident side angle adjuster 44. Fig. 7(d) is the output result of the control unit 80 after adjustment of the incident side angle adjuster 44.

[0051] Fig. 8 is a conceptual diagram illustrating adjustment of the output side angle adjuster. Fig. 8(a) is a conceptual diagram of the laser device before adjustment of the output side angle adjuster 64. Fig. 8(b) is the output result of the control unit 80 before adjustment of the output side angle adjuster 64. Fig. 8(c) is a conceptual diagram of the laser device after adjustment of the output side angle adjuster 64. Fig. 8(d) is the output result of the control unit 80 after adjustment of the output side angle adjuster 64.

[0052] 7 and 8, the incident-side quartz block 51 and the exit-side quartz block 54 are not shown. In the following description, the spot diameter 82 refers to the diameter of the electrical signal output from the photodetector 62. The deflection angle θ of the core 52 at the incident end face 57 arg The deviation is detected by monitoring the spot diameter 82 obtained from the photodetector 62. As shown in FIG. 7(b), the control unit 80 presets a reference size 81 when the optical axis 3a of the laser light 3 incident on the transmission fiber 50 is at an optimum position relative to the central axis 5 of the core. As described above, when the transmission fiber 50 is rotated at a deflection angle θ arg When the laser beam 3 is output from the transmission fiber 50, the divergence angle θ outbecomes larger. In other words, the spot diameter 82 captured by the photodetector 62 becomes larger than the reference size 81. Therefore, as shown in FIGS. 7(c) and 7(d), the operator adjusts the incident-side angle adjuster 44 so that the spot diameter 82 becomes equal to or smaller than the reference size 81. In other words, the operator adjusts the angle of the central axis 4 of the transmission fiber with respect to the optical axis 3a of the laser light 3 focused by the incident-side focusing lens 41 so that the spot diameter 82 becomes equal to or smaller than the reference size 81. This optimizes the relationship between the laser light 3 incident on the transmission fiber 50 and the central axis 5 of the core. The optimized state in this embodiment is a state in which the optical axis 3a of the incident laser light 3 and the central axis 5 of the core are parallel to each other.

[0053] Specifically, if the spot diameter 82 is equal to or larger than the reference size 81, the three adjusters 45 in the incident-side angle adjustment unit 44 are moved to adjust the angle of the transmission fiber 50. For example, when adjuster 45c is fixed as a fulcrum and adjusters 45a and 45b are moved, adjuster 45a is first moved by +1 mrad from the initial position, and if the spot diameter 82 is on a decreasing trend, it is moved by another +1 mrad. This process is repeated until the position moved by -1 mrad from the point where the spot diameter 82 starts to increase is set as the optimal position, and the adjustment is terminated. On the other hand, if the spot diameter 82 starts to increase when adjuster 45a is moved by +1 mrad, it is moved by -1 mrad (returned to the original position). If the spot diameter 82 is on a decreasing trend when it is further moved by -1 mrad, it is moved another -1 mrad. This process is repeated until the position moved by +1 mrad from the point where the increase starts is set as the optimal position, and the adjustment is terminated. The optimum position is a position where, when the optimum position is set as the origin, the emitted light intensity tends to decrease whether the position is moved by +1 mrad or −1 mrad.

[0054] Next, the same operation is performed on the adjuster 45b, and the spot diameter 82 is adjusted to be equal to or smaller than the reference size 81.

[0055] In an actual adjustment procedure, as shown in FIG. 7 , before adjusting the incident-side angle adjuster 44, that is, before adjusting the spot diameter 82 to be equal to or smaller than the reference size 81, the exit-side angle adjuster 64 may be adjusted so that the center position P of the spot diameter coincides with the center position Q of the reference size, as shown in FIG. 8 . This is because it is easier to fit the spot diameter 82 into the reference size 81 when the center position Q of the reference size and the center position P of the spot diameter coincide with each other than when they do not. Therefore, the operator adjusts the angle of the exit-side angle adjuster 64 so that the center position P of the spot diameter coincides with the center position Q of the reference size. In other words, the operator adjusts the angle of the exit end face 58 of the transmission fiber 50 with respect to the connection end face 69 a of the head housing 69 so that the center position P of the spot diameter coincides with the center position Q of the reference size. For example, as shown in the upper part of Figure 7(b), if the spot diameter 82 is misaligned, the tightening amount of adjuster 45a and adjuster 45b is adjusted using adjuster 45C as a fulcrum, so that the center position P of the spot diameter and the center position Q of the reference size are aligned.

[0056] The deviation between the center position Q of the reference size and the center position P of the spot diameter is determined by the deviation angle θ arg This includes not only the deviation of the core center C at the output end face 58 but also the deviation of the core center C at the output end face 58. However, in the present invention, by installing the photodetector 62 so that the distance from when the laser light 3 emitted from the output end face 58 reaches the photodetector 62 is a certain value or more, for example, 50 mm or more, the deviation angle θ at the output end face 58 can be reduced more than the deviation of the core center C at the output end face 58. arg This configuration allows for large deviations to be detected.

[0057] This will be explained using an example in which the distance on the optical path from the exit end face 58 to the photodetector 62 is 50 mm. Under these conditions, if the individual difference in the core center C is 10 μm, the center position P of the spot diameter will only shift by 10 μm. On the other hand, if the deviation angle θ arg If the individual difference in the angle of deviation is 5 mrad, the spot diameter 82 will deviate by 50 mm × 5 mrad = 250 μm.arg It becomes possible to observe the deviation to a large extent.

[0058] In this embodiment, the deviation angle θ at the output end face 58 is larger than the deviation of the core center C at the output end face 58. arg The reason for this is explained below. During laser processing, the deviation angle θ at the output end face 58 is arg The deviation of the core center C at the output end face 58 affects the angle of the optical axis 3a of the laser light 3 output from the machining head 60 relative to the workpiece. On the other hand, the deviation of the core center C at the output end face 58 affects the position of the focal point of the laser light focused by the machining head 60. Here, the output side angle adjustment unit 64 adjusts the angle of the output end face 58 of the transmission fiber 50 relative to the connection end face 69a of the transmission fiber 50 in the head housing 69, so that the angle of the optical axis 3a of the laser light output from the transmission fiber 50 relative to the workpiece changes due to the adjustment of the output side angle adjustment unit 64. Therefore, in this embodiment, the deviation angle θ at the output end face 58 arg The configuration is such that the deviation can be observed to a large extent.

[0059] If the deviation of the center position P of the spot diameter is 10% or less of the diameter of the core 52, the output side angle adjustment unit 64 is not adjusted. This is because if the deviation of the center position P of the spot diameter is 10 mμm or less, the cause is either a deviation of the core center C or a negligibly small deviation angle θ arg In the case of a laser device for which it is strongly required that the focal point and the nozzle center coincide with each other, such as in cutting processing, it is possible to deal with this by providing a separate position adjustment mechanism (not shown) for the output-side focusing lens 67 of the processing head 60 and adjusting the focal point by adjusting the position of the output-side focusing lens 67, etc.

[0060] (Adjustment procedure) FIG. 9 is a diagram showing the connection adjustment procedure after replacing the transmission fiber. This flow is performed after replacing the transmission fiber 50. First, laser oscillation is started (step S1), and it is determined whether the intensity of the emitted light received by the photodetector 62 is equal to or greater than the threshold W (step S2). If the intensity of the light received by the photodetector 62 is lower than the threshold W, the position (incident position) of the optical axis 3a of the laser light 3 incident on the transmission fiber 50 by the incident-side focusing lens 41 is adjusted (step S6). After adjusting the incident position, it is again determined whether the light received by the photodetector 62 is equal to or greater than the threshold W (step S2). This cycle is repeated until the light received by the photodetector 62 is equal to or greater than the threshold W.

[0061] If the intensity of the light received by the photodetector 62 is equal to or greater than the threshold W, it is determined whether the center position P of the spot diameter is within the range of the center position Q of the preset reference size (step S3). If the center position P of the spot diameter is within or outside the range of the preset center position Q, the output-side angle adjuster 64 adjusts the angle of the output end face 58 of the transmission fiber 50 relative to the connection end face 69a of the processing head 60 (head housing 69) (step S7). After adjusting the output-side angle adjuster 64, it is again determined whether the center position P of the spot diameter is within the range of the center position Q of the preset reference size (step S3). This cycle is repeated until the center position P of the spot diameter is within the range of the preset center position Q.

[0062] If the center position P of the spot diameter is within the range of the preset center position Q, it is determined whether the spot diameter 82 received by the photodetector 62 is equal to or smaller than the reference size 81 (step S4). If the spot diameter 82 received by the photodetector 62 is not equal to or smaller than the reference size 81, the incident-side angle adjuster 44 adjusts the angle of the central axis 4 of the transmission fiber relative to the optical axis 3a of the laser light 3 focused by the incident-side focusing lens 41 (step S8). After adjusting the incident-side angle adjuster 44, it is again determined whether the spot diameter 82 received by the photodetector 62 is equal to or smaller than the reference size 81 (step S4). This cycle is repeated until the spot diameter 82 received by the photodetector 62 is equal to or smaller than the reference size 81. If the spot diameter 82 received by the photodetector 62 is equal to or smaller than the reference size 81, the adjustment is terminated (step S5).

[0063] By first adjusting the incident position using the incident-side condenser lens 43 (step S2), it becomes possible to eliminate and monitor the possibility of misalignment of the incident position in the subsequent adjustment (step S4) of the incident-side angle adjuster 44. Furthermore, this flow may be performed not only after replacing the transmission fiber 50, but also periodically thereafter. (Effects, etc.) In this embodiment, the deviation of the core center C at the incident end face 57 of the laser light 3 and the deviation angle θ arg This makes it possible to further suppress deterioration of beam quality after replacement of the transmission fiber 50. In addition, the burden on the worker can be reduced, and furthermore, downtime due to replacement of the transmission fiber 50 can be reduced. In addition, in this embodiment, the deviation angle θ at the output end face 58 can be detected. arg This makes it possible to further improve the precision of the connection adjustment of the transmission fiber 50.

[0064] In this embodiment, by monitoring the laser light 3 emitted from the transmission fiber 50, the deviation of the core center C at the incident end face 57 of the laser light 3 and the deflection angle θ at the incident end face 57 can be detected by a single photodetector 62. arg and the deviation angle θ at the output end face 58 argIn other words, it is possible to detect the deviation of the core center C at the incident end face 57 of the laser light 3, the deviation of the deflection angle θ at the incident end face 57, and arg and the deviation angle θ at the output end face 58 arg There is no need to provide a dedicated photodetector for monitoring the deviation of each of the laser beams. Furthermore, in this embodiment, the angle adjustment is performed using the laser beam 3 emitted from the laser oscillator 10, so there is no need to install a new light source. These are useful in reducing manufacturing costs.

[0065] In the above description, the deviation of the core center C at the incident end face 57 of the laser light and the deflection angle θ at the incident end face 57 are arg and the deviation angle θ at the output end face 58 arg Although the deviation has been explained as being caused by individual differences in the transmission fiber 50, some deviations may occur when the fiber is attached to the laser device 1. In this embodiment, the laser light 3 emitted from the transmission fiber 50b after attachment is monitored and adjusted, so that it is possible to detect and correct not only individual differences in the transmission fiber 50 itself but also individual differences that occur during attachment.

[0066] [Embodiment 2] To make the processing head 60 more compact, it is necessary to make the photodetector 62 smaller, that is, to make the spot diameter 82 smaller. Therefore, in this embodiment, a configuration that allows the processing head 60 to be made smaller is proposed.

[0067] In the following description of the disclosed embodiment, only the configurations different from the first embodiment will be described.

[0068] 10 is a conceptual diagram illustrating embodiment 2. In a head housing 69 of a laser device according to embodiment 2, a collimator lens 66 is provided in the optical path before the partial reflection mirror 61.

[0069] The collimating lens 66 collimates the laser light 3 emitted from the emission end face 58. The partially reflecting mirror 61 reflects a portion, for example, 0.01%, of the laser light 3 collimated by the collimating lens 66 and transmits the remaining laser light 3.

[0070] The photodetector 62 receives the laser light 3b reflected by the partial reflection mirror 61. The mirror 63 reflects the laser light 3b that has passed through the partial reflection mirror 61 toward the irradiation port of the processing head 60. The output-side focusing lens 67 focuses the laser light that has been collimated by the collimating lens 66 toward the object 2.

[0071] Here, the beam size of the laser light 3 emitted from the output end face 58 increases until it is collimated by the collimator lens 66. In other words, the size of the spot diameter 82 received by the photodetector 62 is determined by the distance to the collimator lens 66. Therefore, by providing the collimator lens 66 in the optical path system before the partial reflection mirror 61 as in the second embodiment, the distance required to determine the size of the spot diameter 82 is shorter than in the configuration of the first embodiment in which the spot diameter 82 is determined by the distance from the output end face 58 to the photodetector 62, and as a result, the spot diameter 82 can be made smaller. In other words, it is easy to adjust the spot diameter 82 to match the size of the processing head 60.

[0072] The configuration of the first embodiment and the configuration of the second embodiment are appropriately selected depending on the size of the processing head 60. The connection adjustment procedure of the transmission fiber 50 is the same as the adjustment procedure described in the first embodiment (see FIG. 9).

[0073] [Variations] The configuration of the present disclosure has been described above based on the embodiments, but the present disclosure is not limited to the above embodiments. Furthermore, the materials, numerical values, etc. described in the above embodiments are merely preferred examples and are not limited thereto. Furthermore, the configuration of the laser device can be modified as appropriate within the scope of the technical concept of the present disclosure.

[0074] For example, the adjustment of the condenser lens adjustment unit 43, the incident-side angle adjustment unit 44, and the output-side angle adjustment unit 64 may be automatically controlled by instructions from the control unit 80. In the case of automatic adjustment, this can be realized by providing the condenser lens adjustment unit 43, the incident-side angle adjustment unit 44, and the output-side angle adjustment unit 64 with a receiver capable of communicating with the control unit 80 wirelessly or via a cable, and a motor capable of adjusting each optical system according to instructions from the receiver.

[0075] For example, the photodetector 62 may be a thermopile or the like, as long as it is capable of outputting the light intensity distribution. [Industrial Applicability]

[0076] The present disclosure is useful for a laser device and a transmission fiber connection adjustment method that allow easier position adjustment of a transmission fiber. [Explanation of symbols]

[0077] 1. Laser device 2. Object 3 Laser light 3a optical axis 4. Central axis of transmission fiber 5. Core axis 10 Laser oscillator 40 Light Concentration Unit 41 Condenser lens (incident side condenser lens) 43 Condenser lens adjustment unit 44 Incident side angle adjustment section 50 Transmission Fiber 57 Incidence end face 58 Output end face 60 processing head 69a Connection end face 61 Partially Reflecting Mirror 62 Photodetector 64 Output side angle adjustment unit 66 Collimating Lens 80 Control Unit 81 Standard size 82 spot diameter Q Center position of reference size P Center position of spot diameter S Output light intensity W threshold

Claims

1. a laser oscillator that emits laser light; a condenser lens that condenses the laser light emitted from the laser oscillator; a transmission fiber that transmits the laser light focused by the focusing lens; an incident-side angle adjustment unit that adjusts the angle of the central axis of the transmission fiber with respect to the optical axis of the laser light focused by the focusing lens so that the spot diameter of the laser light emitted from the transmission fiber is equal to or smaller than a reference size.

2. a processing head configured to irradiate an object with the laser light emitted from the transmission fiber; The processing head includes: a partial reflection mirror that reflects a part of the laser light emitted from the transmission fiber; a photodetector that receives the laser light reflected by the partial reflection mirror and outputs a spot diameter of the laser light, The laser device according to claim 1 , wherein the incident-side angle adjuster adjusts the spot diameter of the laser light output by the photodetector to a reference size or less.

3. The photodetector also outputs the intensity of the laser light; 3. The laser device according to claim 2, further comprising a focusing lens adjustment unit that adjusts a position of the focusing lens that focuses the laser light emitted from the laser oscillator so that the intensity of the laser light output by the photodetector is equal to or greater than a threshold.

4. the transmission fiber has an exit end surface from which the laser light is emitted, The processing head is a laser device having a connection end face to which the transmission fiber is connected, 3. The laser device according to claim 2, further comprising an output side angle adjustment unit that adjusts the angle of the output end face of the transmission fiber relative to the connection end face of the processing head so that the center position of the spot diameter of the laser light output by the photodetector and the center position of a preset spot diameter have a predetermined positional relationship.

5. The laser device according to claim 2 , wherein the processing head further comprises a collimating lens in an optical path before the partial reflection mirror.

6. a laser oscillator that emits laser light; a condenser lens that condenses the laser light emitted from the laser oscillator; a transmission fiber that transmits the laser light focused by the focusing lens, a transmission fiber connection adjusting method for adjusting an angle of a central axis of the transmission fiber with respect to an optical axis of the laser light focused by the focusing lens so that a spot diameter of the laser light emitted from the transmission fiber is equal to or smaller than a reference size.

7. 5. A transmission fiber connection adjustment method using the laser device according to claim 4, comprising: A transmission fiber connection adjusting method in which the adjustment of the output side angle adjusting section is performed before the adjustment of the input side angle adjusting section.

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