Laser processing machine and laser processing method

Abstract

A laser processing machine (100) is provided with: a collimator lens (31) that converts a laser beam into collimated light; a condenser lens (36) that condenses the collimated light on a metal plate; a first lens array (32) that arranges a plurality of first microlenses in a planar manner and refracts the laser beam using each first microlens; a second lens array (33) that arranges a plurality of second microlenses in a planar manner with the center disposed at the same position as the center of the first lens array in the optical axis direction and causes the laser beam emitted from each microlens of the first lens array to enter and be refracted using each corresponding second microlens; and a rotation mechanism (331) that rotates at least either the first lens array or the second lens array along the outer periphery thereof.

Description

Technical Field

[0001] This disclosure relates to laser processing machines and laser processing methods. Background Technology

[0002] Laser processing machines that use laser beams emitted from a laser oscillator to cut metal sheets are now widely used. By appropriately setting the incident angle of the laser beam into the metal sheet (for example, setting it to about 80°), the laser processing machine can increase the laser absorption rate in the metal sheet and perform cutting processes efficiently.

[0003] On the other hand, in the cutting of metal plates using laser beams, the width of the cutting groove needs to be adjusted appropriately according to the plate thickness in order to efficiently remove the molten metal. Specifically, the thicker the plate, the wider the cutting groove needs to be.

[0004] In other words, when using a laser beam to cut metal plates, the incident angle of the laser beam into the metal plate and the width of the cutting groove become important parameters.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent No. 6419901

[0008] Patent Document 2: Japanese Patent No. 5767315 Summary of the Invention

[0009] To increase the cleavage width of a laser beam when cutting thicker metal plates, the focusing diameter of the laser beam must be increased. However, increasing the focusing diameter without changing the beam-parameter product results in a smaller incident angle. In other words, the energy density relative to the area of ​​the irradiated metal plate decreases. Therefore, to compensate for the reduced energy density with the same laser beam diameter as when the focusing diameter is smaller, the output must be increased or the cutting speed reduced, but there are limits to this. Consequently, when cutting thicker metal plates, it becomes difficult to maintain a high laser absorptivity and achieve an appropriate cleavage width. Furthermore, if the incident angle of the laser beam decreases, the irradiation angle of the laser beam irradiating the cutting edge approaches 90°, moving away from the Brewster angle. This reduces the absorptivity of the metal plate, making melting of the metal more difficult.

[0010] One aspect of the laser processing machine disclosed herein includes: a collimating lens that converts an incident laser beam into collimated light; a focusing lens that converges the converted collimated light to irradiate a metal plate; a first lens array that comprises a plurality of first microlenses arranged in a planar shape and refracts the incident laser beam using each of the first microlenses; a second lens array that comprises a plurality of second microlenses arranged in a planar shape and configured in the same shape as the first lens array, with its center set at the same position in the optical axis direction as the center of the first lens array, and refracting the laser beam emitted from each microlens of the first lens array using the corresponding second microlenses; and a rotation mechanism that rotates at least one of the first lens array and the second lens array along its outer periphery.

[0011] Therefore, when a laser processing machine of one aspect of this disclosure irradiates a metal plate to be cut with a laser beam that has rotated the first or second lens array, it can create multiple regions with high absorption rates on the metal plate. Thus, the laser processing machine of one aspect of this disclosure can control the incident angle to be close to Brewster's angle to maintain a high laser absorption rate on the metal plate, and can be modified to a focusing diameter that ensures the desired groove width for cutting.

[0012] Furthermore, one aspect of the laser processing method disclosed herein is configured such that at least one of the first lens array and the second lens array is rotated along the outer periphery by a predetermined angle by the rotation mechanism of the laser processing machine, so that the focusing diameter of the laser beam focused by the focusing lens of the laser processing machine becomes a predetermined size.

[0013] Therefore, in one aspect of the laser processing method of this disclosure, when a laser beam, which is incident with a first lens array or a second lens array rotated, is directed onto a metal plate to be cut, multiple regions with high absorption rates can be set on the metal plate. Thus, the laser processing method of this disclosure can control the incident angle to be close to the Brewster angle to maintain a high laser absorption rate on the metal plate, and can be modified to a focusing diameter that ensures the desired groove width for cutting.

[0014] According to one aspect of the laser processing machine and laser processing method of the present invention, the incident angle can be controlled to be close to Brewster's angle to maintain a high laser absorption rate of the metal plate to be cut, and the cutting process can be performed with a focusing diameter that can ensure an appropriate groove width corresponding to the thickness of the metal plate. Attached Figure Description

[0015] Figure 1 This is an overall diagram showing the structure of a laser processing machine according to one embodiment.

[0016] Figure 2This is a diagram illustrating a structural example of a collimation unit included in one embodiment of a laser processing machine.

[0017] Figure 3A This is a front view of the first lens array of a laser processing machine according to one embodiment.

[0018] Figure 3B This is a front view of the second lens array of a laser processing machine according to one embodiment.

[0019] Figure 4A This is a diagram showing the position of a laser beam incident on the first lens array when the microlenses of the first lens array and the second lens array of a laser processing machine in one embodiment are aligned.

[0020] Figure 4B This is a diagram showing the position of a laser beam incident on the second lens array when the microlenses of the first and second lens arrays of a laser processing machine in one embodiment are aligned.

[0021] Figure 4C This is a diagram showing the size of the laser beam (focused beam) emitted onto the metal plate when the microlenses of the first lens array and the second lens array of a laser processing machine in one embodiment are aligned.

[0022] Figure 5A It is a graph showing the energy density distribution of a laser beam incident on a first lens array in one embodiment of a laser processing machine.

[0023] Figure 5B It is a graph showing the energy density distribution of a laser beam injected into a laser processing machine according to one embodiment on a second lens array.

[0024] Figure 6A This is a diagram showing the position of a laser beam incident on the first lens array when the positions of the microlenses in the first lens array and the second lens array of a laser processing machine in one embodiment are inconsistent.

[0025] Figure 6B This is a diagram showing the position of a laser beam incident on the second lens array when the positions of the microlenses in the first and second lens arrays of a laser processing machine in one embodiment are inconsistent.

[0026] Figure 6C This is a diagram showing the size of the laser beam (focused beam) emitted onto the metal plate when the microlenses of the first lens array and the second lens array of a laser processing machine in one embodiment are not in the same position.

[0027] Figure 7This is an enlarged view showing a laser beam incident on a portion of the microlenses within the second lens array of a laser processing machine according to one embodiment.

[0028] Figure 8A This is a diagram showing the image of a laser beam illuminating a focusing lens without rotating the second lens array of a laser processing machine according to one embodiment.

[0029] Figure 8B It is shown in Figure 8A The image shows the image of a laser beam focused on a metal plate in the indicated state.

[0030] Figure 8C This is a diagram (one of) showing the imaging information of a laser beam illuminating a condenser lens when the second lens array of a laser processing machine in one embodiment has been rotated by a predetermined angle.

[0031] Figure 8D It is shown in Figure 8C The image shows the image of a laser beam focused on a metal plate in the indicated state.

[0032] Figure 8E This is a diagram (second one) showing the imaging information of a laser beam illuminating a condenser lens when the second lens array of a laser processing machine in one embodiment has been rotated by a predetermined angle.

[0033] Figure 8F It is shown in Figure 8E The image shows the image of a laser beam focused on a metal plate in the indicated state.

[0034] Figure 9 It is a graph showing the absorption rate relative to the incident angle when a laser beam emitted by a laser processing machine according to one embodiment is incident on a metal plate. Detailed Implementation

[0035] Hereinafter, a laser processing machine according to one embodiment will be described with reference to the accompanying drawings. Figure 1 This is an overall view showing the structure of a laser processing machine 100 according to one embodiment. Figure 2 This is a diagram showing an example of the structure of the collimation unit 30 included in a laser processing machine 100 according to one embodiment. Figure 3A This is a front view of the first lens array 32 of a laser processing machine 100 according to one embodiment. Figure 3B This is a front view of the second lens array 33 of a laser processing machine 100 according to one embodiment.

[0036] One embodiment of the laser processing machine 100 includes: a collimating lens 31 that converts an incoming laser beam into collimated light; a focusing lens 36 that converges the converted collimated light and irradiates a metal plate; a first lens array 32 that is configured by arranging a plurality of first microlenses L1 in a planar shape, and refracts the incoming laser beam using each of the first microlenses L1; a second lens array 33 that is configured by arranging a plurality of second microlenses L2 in a planar shape and having the same shape as the first lens array 32, with its center set at the same position in the optical axis direction as the center of the first lens array 32, and refracting the laser beam emitted from each microlens L1 of the first lens array 32 using each of the corresponding second microlenses L2; ​​and a rotation mechanism 331 that rotates at least one of the first lens array 32 and the second lens array 33 along its outer periphery.

[0037] In one embodiment, the microlenses of the first lens array 32 and the microlenses of the second lens array 33 of the laser processing machine 100 are shaped into regular hexagons or quadrilaterals.

[0038] In one embodiment, the focal length of the microlenses in the second lens array 33 of the laser processing machine 100 is set to be shorter than that of the microlenses in the first lens array 32.

[0039] In one embodiment, the laser processing machine 100 includes a first lens array 32 and a second lens array 33 disposed between the collimating lens 31 and the condenser lens 36.

[0040] like Figure 1 As shown, the laser processing machine 100 includes a laser oscillator 10 that generates and emits a laser beam, a laser processing unit 20, and a processing optical fiber 12 that transmits the laser beam emitted from the laser oscillator 10 to the laser processing unit 20. Furthermore, the laser processing machine 100 includes a control unit 40 for controlling the entire laser processing machine 100. The NC unit 40 is an example of a control device.

[0041] The laser processing machine 100 uses a laser beam emitted from a laser oscillator 10 to cut a metal plate W. The laser oscillator 10 is preferably a laser oscillator that amplifies the excitation light emitted from a laser diode and emits a laser beam of a predetermined wavelength, or a laser oscillator that directly utilizes the laser beam emitted from a laser diode. Examples of laser oscillators 10 include solid-state laser oscillators, fiber laser oscillators, disk laser oscillators, and direct diode laser oscillators (DDL oscillators).

[0042] The processing optical fiber 12 is assembled along the cable guide tubes (not shown) arranged on the X and Y axes of the laser processing unit 20.

[0043] The laser processing unit 20 includes a processing table 21 for placing a metal plate W, a portal-shaped X-axis carriage 22 that moves freely along the X-axis direction on the processing table 21, and a Y-axis carriage 23 that moves freely along the Y-axis direction perpendicular to the X-axis on the X-axis carriage 22. Furthermore, the laser processing unit 20 includes a collimation unit 30 fixed to the Y-axis carriage 23.

[0044] The collimation unit 30 includes: a collimating lens 31 positioned at a predetermined position to receive a laser beam emitted from the emitting end of the processing optical fiber 12; a first lens array 32 receiving the laser beam emitted from the collimating lens 31; and a second lens array 33 receiving the laser beam emitted from the first lens array 32. The collimating lens 31, the first lens array 32, and the second lens array 33 are arranged in the direction of the optical axis of the received laser beam. Furthermore, the center of the second lens array 33 is set at the same position as the center of the first lens array 32 in the optical axis direction.

[0045] The collimating lens 31 is a lens with a positive focal length that converts the incident laser beam into parallel light (collimated light). The detailed structures of the first lens array 32 and the second lens array 33 are described below. Furthermore, the collimating unit 30 has a curved reflector 34 that reflects the laser beam emitted from the second lens array 33 downwards in a direction perpendicular to the Z-axis and Y-axis.

[0046] The collimation unit 30 is fixed to a Y-axis slide 23 that is movable along the Y-axis direction, and the Y-axis slide 23 is disposed on an X-axis slide 22 that is movable along the X-axis direction. Thus, the laser processing unit 20 can move the position where the laser beam emitted from the nozzle 37 irradiates the metal plate W in both the X-axis and Y-axis directions.

[0047] Furthermore, the laser processing unit 20 has a processing head 35 connected to the collimation unit 30 below the collimation unit 30. The processing head 35 has a condenser lens 36 that focuses the laser beam reflected by the curved reflector 34 and directs it toward the metal plate W. The condenser lens 36 is a lens with a positive focal length. A nozzle 37 for emitting a laser beam is detachably mounted at the front end of the processing head 35.

[0048] The collimation unit 30, the processing head 35, and the nozzle 37 constitute a beam irradiation unit that converts the laser beam, which is a diverging light, into collimated light and then focuses it to irradiate the metal plate W.

[0049] Based on the above structure, the laser processing machine 100 can use the processing fiber 12 to transmit the laser beam emitted from the laser oscillator 10 to the laser processing unit 20, and irradiate the metal plate W with the laser beam focused by the focusing lens 36 to cut the metal plate W.

[0050] Next, refer to Figure 2The structure of the straight element 30 will be explained using an example. Figure 2 As shown, the first lens array 32 and the second lens array 33 within the collimation unit 30 are disposed between the collimating lens 31 and the condenser lens 36. Furthermore, the second lens array 33 is mounted on a rotation mechanism 331 for rotating the second lens array 33 along its outer circumference.

[0051] The drive unit 332 uses a rotation mechanism 331 to rotate at least one of the first lens array 32 and the second lens array 33 by a predetermined angle along its outer periphery, so that the focusing diameter of the laser beam focused by the focusing lens 36 becomes a predetermined size. Furthermore, in this embodiment, the second lens array 33 is rotated by the rotation mechanism 331.

[0052] The drive unit 332 drives the rotation mechanism 331, thereby rotating the second lens array 33 along its outer periphery. Thus, the rotation mechanism 331 enables the second lens array 33 to rotate about its center axis. The drive unit 332 is, for example, a motor. The NC device 40 controls the drive unit 332. Alternatively, the drive unit 332 can be controlled by other control devices connected to the NC device 40.

[0053] Here, refer to Figure 3A and Figure 3B The first lens array 32 and the second lens array 33 will be described. For example... Figure 3A As shown, the first lens array 32 is constructed by arranging multiple first microlenses L1 in a planar shape. Furthermore, as... Figure 3B As shown, the second lens array 33 arranges a plurality of second microlenses L2 in a planar shape and forms the same shape as the first lens array 32. In this embodiment, the first microlens L1 and the second microlens L2 are each shaped as a regular hexagon. Furthermore, the focal length of each second microlens L2 is set to be shorter than the focal length of each first microlens L1.

[0054] Next, refer to Figure 2 as well as Figures 4A to 5B The operation performed by the laser processing machine 100 in the following case is explained: the first lens array 32 and the second lens array 33 are arranged in the collimation unit 30 such that the positions of each first microlens L1 and each second microlens L2 are aligned in the optical axis direction.

[0055] Figure 4A This is a diagram showing the position of a laser beam incident on the first lens array 32 when the microlenses of the first lens array 32 and the second lens array 33 of a laser processing machine 100 in one embodiment are aligned. Figure 4BThis is a diagram showing the position of a laser beam incident on the second lens array 33 when the positions of the microlenses of the first lens array 32 and the second lens array 33 of a laser processing machine 100 in one embodiment are aligned. Figure 4C This is a diagram showing the size of the laser beam (focused light) emitted onto the metal plate when the microlenses of the first lens array 32 and the second lens array 33 of a laser processing machine 100 in one embodiment are aligned.

[0056] Figure 5A It is a graph showing the energy density distribution of a laser beam incident on a first lens array 32 in a laser processing machine 100 according to one embodiment. Figure 5B It is a graph showing the energy density distribution of a laser beam injected into a laser processing machine 100 according to one embodiment on a second lens array 33.

[0057] like Figure 2 As shown, if a laser beam is emitted from the emitting end 12e of the processed optical fiber 12 as indicated by the dashed line, the collimating lens 31 converts the emitted laser beam into parallel light (collimated light). Here, parallel light means that the laser beam is parallel. Figure 4A As shown by the dashed line, parallel light emitted from the collimating lens 31 enters the first microlens L1, which corresponds to the core diameter of the beam within the first lens array 32. At this time, as... Figure 5A As shown, the energy density distribution of the laser beam on the single-dotted dashed line E-E' of the first lens array 32 becomes a curve with the peak value centered at a single point.

[0058] Each first microlens L1, after entering the laser beam, refracts the laser beam, focusing it at a position a predetermined focal length away. For example... Figure 4B As shown by the dashed line, the laser beam, after passing through the focal point, is directed into a predetermined range within the center of each corresponding second microlens L2 in the second lens array 33. At this time, as... Figure 5B As shown, the energy density distribution of the laser beam on the dashed line F-F' of the second lens array 33 exhibits a peak value that is dispersed according to each second microlens L2, with the peak value increasing closer to the center. Furthermore, at this time, the center position SL of each second microlens L2 after the laser beam is incident coincides with the center SB of the laser beam incident onto that second microlens L2. Each second microlens L2 after the laser beam is incident converts the laser beam into parallel light.

[0059] Parallel light emitted from each of the second microlenses L2 is reflected by the curved mirror 34, bending its path and directing it towards the condenser lens 36. The condenser lens 36 converges the parallel light in such a way that the focal point is at or near the surface of the metal plate W, causing the laser beam to irradiate the metal plate W. In this case, the laser beam irradiating the metal plate W is as follows: Figure 4C The light is focused on a single point.

[0060] The focusing diameter d of the focusing point at this time is as shown in the following formula (1).

[0061] Formula 1

[0062]

[0063] Here, f collimate It is the focal length of collimating lens 31, f focus It is the focal length of the condenser lens 36, d core It is the core diameter of the laser beam.

[0064] Next, refer to Figure 2 as well as Figures 6A-7 The operation performed by the laser processing machine 100 under the following conditions will be explained: Starting from a state where the positions of each first microlens L1 in the first lens array 32 are consistent with the positions of each second microlens L2 in the second lens array 33, the second lens array 33 is moved along the outer circumferential direction... Figure 4B The arrow direction is rotated by a predetermined angle, causing the position of the corresponding microlens to deviate.

[0065] Figure 6A This is a diagram showing the position of a laser beam incident on the first lens array 32 when the positions of the microlenses of the first lens array 32 and the second lens array 33 of a laser processing machine 100 in one embodiment are inconsistent. Figure 6B This is a diagram showing the position of a laser beam incident on the second lens array 33 when the positions of the microlenses of the first lens array 32 and the second lens array 33 of a laser processing machine 100 in one embodiment are inconsistent. Figure 6C This is a diagram showing the size of the laser beam (focused light) emitted onto the metal plate when the microlenses of the first lens array and the second lens array of the laser processing machine in the embodiment are not in the same position.

[0066] Figure 7 This is an enlarged view showing a portion of the microlenses within the second lens array 33 of a laser processing machine 100 according to one embodiment, and a laser beam incident on the microlenses within the second lens array 33.

[0067] In this case, if a laser beam is emitted from the emitting end 12e of the processing optical fiber 12 and converted into parallel light by the collimating lens 31, then as Figure 6A As shown by the dashed line, the laser beam is directed into the first microlens L1 within the central range corresponding to the core diameter of the beam within the first lens array 32.

[0068] Each first microlens L1, after entering the laser beam, focuses the laser beam at a position away from a predetermined focal length. For example... Figure 6BAs shown by the dashed line, the laser beam, after passing through the focal point, is directed into predetermined ranges of the corresponding second microlenses L2 within the second lens array 33. Here, for the second microlens L21 at the center of the second lens array 33, the laser beam is directed into the range around its center; however, for the second microlenses L2 outside L21, the beam is directed into a range offset from the center of that second microlens L2. Thus, a deviation occurs between the center position SL of the second microlenses L2 (excluding the second microlens L21) into which the laser beam is directed and the center SB of the laser beam directed into that second microlens L2.

[0069] At this time, since the focal length of the second microlens L2 is set to be shorter than that of the first microlens L1, even if there is a deviation between the center position SL of the second microlens L2 and the center SB of the laser beam injected into the second microlens L2, the laser beam can still be injected into the second microlens L2.

[0070] If a deviation occurs between the center position SL of the second microlens L2 and the center SB of the laser beam incident on the second microlens L2, the focal point of the multiple laser beams emitted from each of the second microlenses L2 and reflected by the curved mirror 34 will deviate after being converged by the condenser lens 36. The further the position of the microlens L2 is from the center of the second lens array 33, the greater this deviation will be.

[0071] As an example, Figure 7 The diagram shows an enlarged view of the second microlens L21 located at the center of the second lens array 33, a laser beam B21 incident on L21, the second microlens L22 adjacent to L21 and a laser beam B22 incident on L22, and the second microlens L23 adjacent to L22 and a laser beam B23 incident on L23. Here, the second microlens L23 is the second microlens L2 located at the position furthest from the second microlens L21 (the outermost position within the second lens array 33) within the second lens array 33.

[0072] Here, when the center position of the second microlens L21 is set as SL21, the center position of the laser beam B21 is set as SB21, the center position of the second microlens L23 is set as SL23, the center position of the laser beam B23 is set as SB23, and the rotation angle of the second lens array 33 is set as θ, although SL21 and SB21 are the same, an angle θ is generated between the straight line connecting SL21 and SL23 and the straight line connecting SB21 and SB23.

[0073] Thus, the multiple laser beams emitted from each of the second microlenses L2 of the second lens array 33 and reflected by the curved reflector 34 are converged by the condenser lens 36, as shown in the image. Figure 6CThe focal point position deviates, and the focusing diameter d2 appears to increase. The focusing diameter d2 at this time is shown in equation (2) below.

[0074] Formula 2

[0075]

[0076] Here, r is the distance from the center position SL21 of the second microlens L21 located at the center of the second lens array 33 to the center position SL23 of the outermost second microlens L23 into which the laser beam is incident; θ is the rotation angle of the second lens array 33; and f is the distance from the center position SL21 of the second microlens L21 located at the center of the second lens array 33 to the center position SL23 of the outermost second microlens L23 into which the laser beam is incident. array d is the focal length of each of the second microlenses L2 in the second lens array 33, and d is the focusing diameter of the laser beam emitted from each of the second microlenses L2 in the second lens array 33 after being focused by the focusing lens 36.

[0077] Figures 8A to 8F The simulation results show the changes in the focusing diameter of the laser beam caused by varying the rotation angle of the second lens array 33 in the laser processing machine 100 configured as described above. Here, the fiber core diameter of the laser beam emitted from the processing fiber 12 is set to... The focal length of the collimating lens 31 is set to f120, the focal length of each first microlens L1 in the first lens array 32 is set to f44.5, the focal length of each second microlens L2 in the second lens array 33 is set to f42.3, and the focal length of the condenser lens 36 is set to f150. Furthermore, Figure 9 The absorptivity is shown relative to the incident angle when the laser beam is incident on the metal plate.

[0078] Figure 8A This is a diagram showing the image of a laser beam illuminating a focusing lens 36 without rotating the second lens array 33 of the laser processing machine 100 in one embodiment (rotation angle 0°). Figure 8B It is shown in Figure 8A The image shows the image of a laser beam focused on a metal plate W in the indicated state.

[0079] Figure 8C This is a diagram showing the image of a laser beam illuminating a focusing lens 36 when the second lens array 33 of a laser processing machine 100 in one embodiment is rotated by a predetermined angle (0.2° along the outer periphery). Figure 8D It is shown in Figure 8C The image shows the image of a laser beam focused on a metal plate W in the indicated state.

[0080] Figure 8EThis is a diagram showing the image of a laser beam illuminating a focusing lens 36 when the second lens array 33 of a laser processing machine 100 of one embodiment is rotated by a predetermined angle (0.4° along the outer periphery). Figure 8F It is shown in Figure 8E The image shows the image of a laser beam focused on a metal plate W in the indicated state.

[0081] Figure 9 It is a graph showing the absorption rate relative to the incident angle when a laser beam irradiated by a laser processing machine 100 of one embodiment is incident on a metal plate W.

[0082] Figure 8A , Figure 8C as well as Figure 8E The width of the shooting information is 50mm. Figure 8B , Figure 8D as well as Figure 8F The width of the captured information is 1mm.

[0083] Based on the above simulation results, such as Figure 8A , Figure 8C as well as Figure 8E As shown, regardless of whether the second lens array 33 rotates, the beam diameter of the laser beam illuminating the condenser lens 36 remains essentially unchanged. If the beam diameter of the laser beam illuminating the condenser lens 36 remains unchanged, then the incident angle of the laser beam entering the metal plate W also remains unchanged. The absorptivity relative to the incident angle of the laser beam entering the metal plate is as follows: Figure 9 As shown in the graph, the incident angle (around 80°) with the highest absorption rate is the Brewster angle. Therefore, by pre-setting the incident angle of the laser beam into the metal plate W to be close to the Brewster angle, this incident angle can be maintained even when the second lens array 33 is rotated, thereby ensuring a certain laser absorption rate and energy density on the metal plate W.

[0084] In contrast, such as Figure 8B , Figure 8D as well as Figure 8F As shown, the larger the rotation angle of the second lens array 33, the larger the focusing diameter of the laser beam focused on the metal plate W. If the focusing diameter is increased by increasing the rotation angle of the second lens array 33, the width of the cutting groove in the metal plate W can be enlarged. In other words, by adjusting the rotation angle of the second lens array 33, the focusing diameter of the laser beam focused on the metal plate W by the focusing lens 36 can be adjusted, thus changing the width of the cutting groove.

[0085] Therefore, for a laser beam with the same energy, if the focusing diameter is increased without changing the beam or parameter product, the energy density of the laser beam irradiating the metal plate W will decrease. However, in this embodiment, a high laser absorptivity can be maintained at an incident angle close to Brewster's angle, and multiple regions with high absorptivity can be set in the metal plate W. The metal plate W can be melted with a focusing diameter that ensures a groove width corresponding to the thickness of the metal plate W.

[0086] To summarize again, from Figure 8A , Figure 8C , Figure 8E , Figure 8B , Figure 8D as well as Figure 8F It is understandable that regardless of whether the second lens array 33 rotates, the beam diameter of the laser beam irradiating the focusing lens 36 will not change significantly. Therefore, the incident angle of the laser beam into the metal plate W will not change. However, since multiple regions with high absorption rates can be set by rotating the second lens array 33, the size of the focusing diameter of the laser beam focused on the metal plate W can be adjusted, and the width of the groove for cutting can be changed.

[0087] In the above embodiments, the case where the position of the first microlens L1 is deviated from the position of the corresponding second microlens L2 by rotating the second lens array 33 has been described. However, this disclosure is not limited to this; the same effect can be obtained by rotating at least one of the first lens array 32 and the second lens array 33 to deviate the corresponding microlenses from the predetermined angle. For example, the position of the first microlens L1 from the position of the second microlens L2 can also be deviated from the predetermined angle by rotating the first lens array 32 or by rotating the first lens array 32 and the second lens array 33 in opposite directions.

[0088] Furthermore, in the above embodiment, the case where the plurality of first microlenses L1 in the first lens array 32 within the alignment unit 30 and the plurality of second microlenses L2 in the second lens array 33 are respectively hexagonal has been described, but it is not limited to this. It is acceptable for them to be arranged in a shape in which adjacent microlenses can be arranged without gaps between them, for example, they can also be quadrilateral.

[0089] Furthermore, in the above embodiments, the case where the first microlens L1 and the second microlens L2 are composed of convex lenses has been described, but it is not limited to this. It is also possible that the first microlens L1 is composed of a convex lens and the second microlens L2 is composed of a concave lens.

[0090] Furthermore, in the above embodiment, the case where the first lens array 32 and the second lens array 33 are positioned between the collimating lens 31 and the condenser lens 36 has been described. With this configuration, the positions of the first lens array 32 and the second lens array 33 can be easily determined. However, this structure is not limited to; the first lens array 32 and the second lens array 33 may also be positioned between the processing fiber 12 and the collimating lens 31, or between the condenser lens 36 and the focusing point.

[0091] Furthermore, the aforementioned laser processing machine 100 can also be equipped with a zoom function to adjust the focal length of the laser beam.

[0092] This disclosure is not limited to the embodiments described above, and various modifications can be made without departing from the spirit of this disclosure.

[0093] The disclosure of this application is related to the subject matter set forth in Japanese Patent Application No. 2021-029795 filed on February 26, 2021, and all of the above disclosures are incorporated herein by reference.

Claims

1. A laser processing machine, characterized in that, have: A collimating lens, which converts an incoming laser beam into collimated light; A condensing lens, which focuses the converted collimated light and directs it toward the metal plate; The first lens array is formed by arranging multiple first microlenses in a planar shape, and uses each first microlens to refract the incident laser beam; The second lens array arranges multiple second microlenses in a planar shape and forms the same shape as the first lens array. The center is set at the same position as the center of the first lens array in the optical axis direction. The corresponding second microlenses are used to allow the laser beam emitted from each microlens of the first lens array to enter and be refracted. as well as A rotating mechanism that causes either the first lens array or the second lens array to rotate along its outer periphery. The first lens array and the second lens array are arranged in a specific configuration.

2. The laser processing machine according to claim 1, characterized in that, The microlenses of the first lens array and the microlenses of the second lens array are shaped as regular hexagons or quadrilaterals.

3. The laser processing machine according to claim 1 or 2, characterized in that, The focal length of the microlenses in the second lens array is set to be shorter than that of the microlenses in the first lens array.

4. The laser processing machine according to claim 1 or 2, characterized in that, The first lens array and the second lens array are disposed between the collimating lens and the condensing lens.

5. The laser processing machine according to claim 3, characterized in that, The first lens array and the second lens array are disposed between the collimating lens and the condensing lens.

6. A laser processing method, wherein the laser processing is performed by the laser processing machine according to any one of claims 1 to 5, characterized in that, The aforementioned rotating mechanism rotates at least one of the first lens array and the second lens array by a predetermined angle along the outer periphery, so that the focusing diameter of the laser beam focused by the aforementioned focusing lens becomes a predetermined size.

Images