Laser processing machine

Abstract

A first galvanometer mirror (32a) has a reflective coating applied to a first incident plane on which a laser beam is incident, and reflects the laser beam incident on the first incident plane. A second galvanometer mirror (32b) has a reflective coating applied to a second incident plane on which the laser beam is incident, and reflects the laser beam incident on the second incident plane. The first galvanometer mirror (32a) and the second galvanometer mirror (32b) are formed of a glass material that transmits a portion of the laser beam that is incident on the first and second incident planes and is not reflected by the reflective coating but is transmitted through the reflective coating and penetrates into the interior. A first damper (41) and a second damper (42) absorb the laser beam transmitted through the first galvanometer mirror (32a) and the second galvanometer mirror (32b).

Description

laser processing machine

[0001] The present disclosure relates to a laser processing machine.

[0002] Patent Documents 1 to 3 describe laser processing machines that process a workpiece by vibrating a laser beam emitted from a processing head using a galvanometer mirror of a galvanometer scanner unit.

[0003] Patent No. 5388948 Patent No. 6272587 Patent No. 6748150

[0004] To oscillate a laser beam at a high frequency, a galvanometer mirror is generally made of silicon (Si) or silicon carbide (SiC), which can increase its rigidity. A reflective coating is applied to the surface of the galvanometer mirror to reflect the incident laser beam. In recent years, laser beams emitted by laser oscillators have become increasingly powerful. Even if the reflectivity of a laser beam due to a reflective coating is, for example, 99.9%, the light absorption rate of silicon or silicon carbide is nearly 100%, so the galvanometer mirror generates heat due to the high-power laser beam that passes through the reflective coating without being reflected. Increasing the size of the galvanometer mirror can reduce heat generation from the galvanometer mirror.

[0005] On the other hand, there is a demand for a high vibration frequency of 1 kHz or more for the galvanometer mirror. Larger galvanometer mirrors have larger inertia, making it difficult to vibrate them at the required high frequency. Therefore, there is a demand for a laser processing machine that can suppress heat generation in the galvanometer mirror and vibrate the galvanometer mirror at a high frequency.

[0006] In one aspect of one or more embodiments, a processing head includes a collimation lens that converts a diverging laser beam into collimated light, a galvanometer scanner unit that receives the laser beam emitted from the collimation lens and vibrates the laser beam to be irradiated onto a workpiece to be processed, and a focusing lens that focuses the laser beam emitted from the galvanometer scanner unit and irradiates the workpiece, wherein the galvanometer scanner unit has a first incident plane on which the laser beam is incident and is coated with a reflective coating, a first galvanometer mirror that reflects the laser beam that has been incident on the first incident plane, and a focusing lens that rotates the first galvanometer mirror. a second galvanometer mirror having a second incident plane on which a laser beam is incident and having a reflective coating applied thereto, the second galvanometer mirror having a second incident plane on which a laser beam is incident and reflecting the laser beam that has been incident on the second incident plane; and a second galvanometer motor that drives to rotate the second galvanometer mirror, the first and second galvanometer mirrors being formed of a glass material that transmits a portion of the laser beam that has been incident on the first and second incident planes but has not been reflected by the reflective coating and has penetrated the reflective coating to enter the interior thereof, and the laser processing machine is further provided with first and second dampers that absorb the laser beam that has been transmitted through the first and second galvanometer mirrors.

[0007] According to one or more embodiments of the laser processing machine, heat generation in the galvanometer mirror can be suppressed and the galvanometer mirror can be vibrated at a high frequency.

[0008] FIG. 1 is a diagram illustrating a laser processing machine according to one or more embodiments. FIG. 2 is a perspective view illustrating a galvanometer scanner unit included in the laser processing machine according to one or more embodiments. FIG. 3 is a perspective view of a galvanometer mirror according to a first configuration example, as viewed from the back. FIG. 4 is a front view of the galvanometer mirror according to the first configuration example. FIG. 5 is a rear view of the galvanometer mirror according to the first configuration example. FIG. 6A is a plan view illustrating chamfering of four corners for forming the galvanometer mirror according to the first configuration example from a rectangular parallelepiped sapphire glass plate. FIG. 6B is a side view illustrating chamfering of a partial thickness for forming the galvanometer mirror according to the first configuration example from a rectangular parallelepiped sapphire glass plate. FIG. 7 is a perspective view illustrating an attachment structure of the galvanometer mirror according to the first configuration example to the shaft of a galvanometer motor. FIG. 8 is a perspective view of a galvanometer mirror according to a second configuration example, as viewed from the back. FIG. 9 is a front view of the galvanometer mirror according to the second configuration example. FIG. 10 is a rear view of the galvanometer mirror according to the second configuration example. Fig. 11 is a side view showing partial thickness chamfering for forming a galvanometer mirror of the second configuration example from a rectangular parallelepiped synthetic quartz plate. Fig. 12 is a perspective view of a galvanometer mirror of a modified example of the second configuration example, seen from the back. Fig. 13 is a front view of a modified galvanometer mirror of the modified example of the second configuration example. Fig. 14 is a back view of a modified galvanometer mirror of the modified example of the second configuration example. Fig. 15 is a cross-sectional view showing a detailed configuration example of a collimator unit provided in the laser processing machine according to the first embodiment. Fig. 16 is a cross-sectional view showing a detailed configuration example of a collimator unit provided in the laser processing machine according to the second embodiment. Fig. 17 is a top view showing a detailed configuration example of a collimator unit provided in the laser processing machine according to the second embodiment.

[0009]

[0023] A laser processing machine according to one or more embodiments will be described below with reference to the accompanying drawings. First, an example of the overall configuration of a laser processing machine according to one or more embodiments will be described. In Fig. 1, a laser processing machine 100 includes a laser oscillator 10, a process fiber 12, a laser processing unit 20, an NC device 50, and an assist gas supply device 80.

[0010] The laser oscillator 10 generates and emits a laser beam, and the process fiber 12 transmits the laser beam emitted from the laser oscillator 10 to the laser processing unit 20. Typically, the laser oscillator 10 is a fiber laser oscillator that emits a laser beam with a wavelength of 1060 nm to 1080 nm. The laser oscillator 10 is not limited to a fiber laser oscillator. The NC device 50 is an example of a control device that controls each part of the laser processing machine 100.

[0011] The laser processing unit 20 has a processing table 21 on which the sheet metal W, which is the workpiece to be processed, is placed, a gate-shaped X-axis carriage 22, a Y-axis carriage 23, a collimator unit 30 fixed to the Y-axis carriage 23, and a processing head 35. The X-axis carriage 22 is configured to be movable in the X-axis direction on the processing table 21. The Y-axis carriage 23 is configured to be movable in the Y-axis direction perpendicular to the X-axis on the X-axis carriage 22. The X-axis carriage 22 and the Y-axis carriage 23 function as a movement mechanism that moves the processing head 35 along the surface of the sheet metal W in the X-axis direction, the Y-axis direction, or any combined direction of the X-axis and Y-axis directions.

[0012] Instead of moving the processing head 35 along the surface of the metal sheet W, the processing head 35 may be configured to be fixed in position and the metal sheet W may move. The laser processing machine 100 may be provided with a movement mechanism that moves the processing head 35 relative to the surface of the metal sheet W.

[0013] The processing head 35 is fitted with a nozzle 36 having a circular opening 36a at its tip, which emits a laser beam from the opening 36a. The laser beam emitted from the opening 36a of the nozzle 36 is irradiated onto the metal sheet W. An assist gas supply device 80 supplies nitrogen, oxygen, or the like as an assist gas to the processing head 35. When the metal sheet W is processed, the assist gas is sprayed onto the metal sheet W from the opening 36a.

[0014] 2, the collimator unit 30 includes a collimation lens 301, a galvanometer scanner unit 302, and a bend mirror 303. The collimation lens 301 converts the divergent laser beam emitted from the process fiber 12 into parallel light (collimated light). The galvanometer scanner unit 302 includes a galvanometer motor 33a (first galvanometer motor) and a galvanometer motor 33b (second galvanometer motor) that drive a galvanometer mirror 32a (first galvanometer mirror) and a galvanometer mirror 32b (second galvanometer mirror) to rotate them within a predetermined angle range, respectively.

[0015] The collimated laser beam emitted from the collimation lens 301 is incident on the galvanometer mirror 32a, which reflects the incident laser beam. The laser beam reflected by the galvanometer mirror 32a is incident on the galvanometer mirror 32b, which reflects the incident laser beam. The laser beam reflected by the galvanometer mirror 32b is incident on the bend mirror 303. The bend mirror 303 reflects the laser beam emitted from the galvanometer scanner unit 302 downward in the Z-axis direction, which is perpendicular to the X-axis and Y-axis.

[0016] 2, the galvanometer motors 33a and 33b are fixed to a support member (not shown), and the positions of the galvanometer mirrors 32a and 32b within the space of the collimator unit 30 are set. The galvanometer mirrors 32a and 32b may be collectively referred to as galvanometer mirrors 32, and the galvanometer motors 33a and 33b may be collectively referred to as galvanometer motors 33. The detailed configuration of the collimator unit 30 will be described later.

[0017] The processing head 35 includes a focusing lens 304 that focuses the laser beam reflected by the bend mirror 303 and irradiates the metal plate W with the focused laser beam.

[0018] The laser processing machine 100 is centered so that the laser beam emitted from the opening 36a of the nozzle 36 is positioned at the center of the opening 36a. In the standard state, the laser beam is emitted from the center of the opening 36a. The galvanometer scanner unit 302 functions as a beam vibration mechanism that vibrates the laser beam, which travels through the processing head 35 and is emitted from the opening 36a, within the opening 36a. The NC device 50 controls the galvanometer motor 33a to rotate the galvanometer mirror 32a, and controls the galvanometer motor 33b to rotate the galvanometer mirror 32b.

[0019] The galvano scanner unit 302 can displace the laser beam irradiated onto the metal sheet W in the X-axis direction, the Y-axis direction, or any combined direction of the X-axis and Y-axis directions under the control of the NC device 50. This allows the galvano scanner unit 302 to vibrate the laser beam in a direction parallel to the traveling direction of the processing head 35 (laser beam), in a direction perpendicular to the traveling direction, or so that the beam spot draws a circle.

[0020] Next, configuration examples of the galvanometer mirror 32 will be described in detail. In a first configuration example of the galvanometer mirror 32, the galvanometer mirror 32 is formed using sapphire glass as the glass material. The galvanometer mirror 32 formed using sapphire glass in the first configuration example will be referred to as galvanometer mirror 32S. In a second configuration example of the galvanometer mirror 32, the galvanometer mirror 32 is formed using synthetic quartz as the glass material. The galvanometer mirror 32 formed using synthetic quartz in the second configuration example will be referred to as galvanometer mirror 32Q (or 32Q'). Any of the galvanometer mirrors 32S, 32Q, and 32Q' is used as the galvanometer mirrors 32a and 32b in FIG. 2. The galvanometer mirrors 32S, 32Q, and 32Q' will be described in detail in order.

[0021] <First Configuration Example> Figures 3 to 5 are a perspective view, a front view, and a rear view, respectively, of the galvanometer mirror 32S as seen from the back. Sapphire glass is formed by artificially crystallizing high-purity aluminum oxide to large crystals. As will be described later, the galvanometer mirror 32S is shaped as shown in Figures 3 to 5 by chamfering multiple faces of a rectangular sapphire glass plate.

[0022] 3 to 5, a laser beam is incident on the incident plane S11. The incident plane S11 is coated with a reflective coating made of a dielectric multilayer film that reflects a laser beam in a predetermined wavelength band. The incident plane S11 has a reflectance of 99.5% or more for laser beams with wavelengths of 1040 nm to 1150 nm. Therefore, the incident plane S11 reflects 99.5% or more of the incident laser beam.

[0023] As will be described later, the lower end of the galvanometer mirror 32S in Fig. 3 is the end that is connected to the tip of the shaft 331 (see Fig. 7) of the galvanometer motor 33. A first end face 321 located on the lower end side is connected to the incident plane S11. A second end face 322 located on the opposite side of the shaft 331 from the first end face 321 is also connected to the incident plane S11. The direction connecting the first end face 321 and the second end face 322 is defined as the length direction.

[0024] As shown in FIG. 4 , the length from the first end face 321 to the second end face 322 is L32. The widest portion 32WP is the portion that is widest in the width direction perpendicular to the length direction. The width of the widest portion 32WP is W32. The length L32 and the width W32 have a relationship of L32 > W32. As an example, the length L32 is approximately 33 mm, and the width W32 is approximately 22 mm. The widest portion 32WP is located closer to the second end face 322 than the center of the length L32 of the galvanometer mirror 32S. The entire lengthwise range of the widest portion 32WP is located closer to the second end face 322 than the center of the length L32.

[0025] 3 to 5 , the first side end surface 323 and the second side end surface 324 respectively connect both widthwise ends of the first end surface 321 to both widthwise ends of the widest portion 32WP. The widthwise distance between the first side end surface 323 and the second side end surface 324 increases from the first end surface 321 toward the widest portion 32WP. The third side end surface 325 and the fourth side end surface 326 respectively connect both widthwise ends of the second end surface 322 to both widthwise ends of the widest portion 32WP. The widthwise distance between the third side end surface 325 and the fourth side end surface 326 increases from the second end surface 322 toward the widest portion 32WP.

[0026] The galvanometer mirror 32S has a thickest portion 327 in the center in the width direction. As an example, the thickness of the thickest portion 327 is 3 mm. In the galvanometer mirror 32S, the thickest portion 327 is formed over the entire range from the first end face 321 to the second end face 322. The surface of the thickest portion 327 is a flat surface S12. The first side portion 328 and the second side portion 329 are provided on both sides of the thickest portion 327 in the width direction. The thicknesses of the first side portion 328 and the second side portion 329 become thinner from the thickest portion 327 toward both ends in the width direction. The surfaces of the first side portion 328 and the second side portion 329 are flat surfaces S13 and S14, respectively.

[0027] The galvanometer mirror 32S having the above-described shape can be formed by chamfering the four hatched corners C1 to C4 of the rectangular parallelepiped sapphire glass plate 320S as shown in FIG. 6A, and by chamfering the hatched areas T1 and T2 of the sapphire glass plate 320S in the thickness direction as shown in FIG. 6B.

[0028] Of the laser beams incident on the incident plane S11, a small portion that is not reflected by the reflective coating penetrates the reflective coating and enters the interior of the galvanometer mirror 32S. Because the optical absorption rate of sapphire glass, the glass material forming the galvanometer mirror 32S, is less than 1%, the galvanometer mirror 32S transmits more than 99% of the laser beam that penetrates its interior. Therefore, the galvanometer mirror 32S generates almost no heat due to the laser beam that passes through it without being reflected by the reflective coating. Therefore, heat generation is suppressed even if the beam diameter of the collimated light emitted from the collimation lens 301 is narrowed, so there is no need to enlarge the galvanometer mirror 32S, and it can be minimized in size.

[0029] The flat surfaces S12 to S14 are preferably coated with an anti-reflection coating made of a dielectric multilayer film, and the flat surfaces S12 to S14 on which the anti-reflection coating is applied have a transmittance of 98% or more for laser beams with wavelengths of 1040 nm to 1150 nm.

[0030] 7, a fixing portion 332 for fixing the end of the galvanometer mirror 32S on the first end face 321 side is provided at the tip of the shaft 331 of the galvanometer motor 33. The end of the galvanometer mirror 32S on the first end face 321 side is inserted between a pair of protruding walls of the fixing portion 332 and adhered with an adhesive, thereby fixing the galvanometer mirror 32S to the fixing portion 332. In this way, the galvanometer mirror 32S is connected to the shaft 331 of the galvanometer motor 33, and rotation of the shaft 331 causes the galvanometer mirror 32S to rotate integrally.

[0031] With the galvanometer mirror 32S, the chamfering of the four corners C1 to C4 and the chamfering of the thickness direction of the regions T1 and T2 allows for a significant reduction in inertia compared to the inertia of a rectangular parallelepiped sapphire glass plate 320S. The galvanometer mirror 32S can suppress heat generation, allowing for a reduction in size of the galvanometer mirror 32S, which in turn reduces inertia. Therefore, if the laser processing machine 100 uses the galvanometer mirror 32S as the galvanometer mirror 32, the galvanometer mirror 32 can be vibrated at a high frequency. The high frequency is, for example, 1 kHz or higher.

[0032] When the galvanometer mirror 32S is rotated by the galvanometer motor 33 within a predetermined angle range, if the galvanometer mirror 32S is deformed due to vibration of the galvanometer mirror 32S, the beam profile of the laser beam emitted from the galvanometer mirror 32S deteriorates. The deterioration of the beam profile of the laser beam reduces the brightness of the laser beam on the surface of the metal sheet W. The brightness of the laser beam on the surface of the metal sheet W is set to 100% when the laser beam emitted from the galvanometer mirror 32S is irradiated onto the metal sheet W while the galvanometer motor 33 is not driving the galvanometer mirror 32S. It is preferable to set the thickness of the thickest portion 327 to a thickness that will provide a brightness of at least 98% when the laser beam emitted from the galvanometer mirror 32S is irradiated onto the metal sheet W while the galvanometer motor 33 is driving the galvanometer mirror 32S and the galvanometer mirror 32S is deformed.

[0033] Galvanometer mirror 32S has a shape in which four corners C1 to C4 and thickness regions T1 and T2 are chamfered, and therefore is more susceptible to deformation than rectangular sapphire glass plate 320S. If the thickness of thickest portion 327 is set to a thickness that can obtain the maximum laser beam brightness of 98% or more, as described above, deformation of galvanometer mirror 32S is not substantially a problem.

[0034] <Second Configuration Example> Figures 8 to 10 are a perspective view, a front view, and a rear view, respectively, of the galvanometer mirror 32Q as seen from the back. As will be described later, the galvanometer mirror 32Q is shaped as shown in Figures 8 to 10 by chamfering multiple faces of a rectangular parallelepiped synthetic quartz plate. In the second configuration example, parts that are substantially the same as those in the first configuration example are given the same reference numerals, and their description may be omitted.

[0035] 8 to 10, a laser beam is incident on the incident plane S21. The incident plane S21 is coated with a reflective coating made of a dielectric multilayer film that reflects a laser beam in a predetermined wavelength band. The incident plane S21 has a reflectivity of 99.5% or more for laser beams with wavelengths of 1040 nm to 1150 nm. Therefore, the incident plane S21 reflects 99.5% or more of the incident laser beam. The first end face 321 and the second end face 322 are connected to the incident plane S21.

[0036] 9 , the length from the first end face 321 to the second end face 322 is L32, and the width of the widest portion 32WP is W32. As with the galvanometer mirror 32S, the length L32 and the width W32 have a relationship of L32 > W32. As an example, the length L32 is approximately 33 mm, and the width W32 is approximately 22 mm. The widest portion 32WP is located closer to the second end face 322 than the center of the length L32 of the galvanometer mirror 32Q.

[0037] 8 to 10 , the first side end surface 323 and the second side end surface 324 respectively connect both widthwise ends of the first end surface 321 to both widthwise ends of the widest portion 32WP. The widthwise distance between the first side end surface 323 and the second side end surface 324 increases from the first end surface 321 toward the widest portion 32WP. The third side end surface 325 and the fourth side end surface 326 respectively connect both widthwise ends of the second end surface 322 to both widthwise ends of the widest portion 32WP. The widthwise distance between the third side end surface 325 and the fourth side end surface 326 increases from the second end surface 322 toward the widest portion 32WP.

[0038] The galvanometer mirror 32Q has a thickest portion 327 in the widthwise center thereof. For example, the thickness of the thickest portion 327 is approximately 4.4 mm. In the galvanometer mirror 32Q, the thickest portion 327 does not extend over the entire range from the first end face 321 to the second end face 322, but extends over the range from the first end face 321 to the widest portion 32WP. The end of the thickest portion 327 on the second end face 322 side is located at a predetermined position in the longitudinal direction of the widest portion 32WP. The surface of the thickest portion 327 forms a flat surface S22.

[0039] The first side portion 328 and the second side portion 329 are provided on both sides in the width direction of the thickest portion 327. The thicknesses of the first side portion 328 and the second side portion 329 become thinner from the thickest portion 327 toward both ends in the width direction. The surfaces of the first side portion 328 and the second side portion 329 are flat surfaces S23 and S24, respectively.

[0040] Galvanometer mirror 32Q has inclined tip 330 formed on the second end face 322 side. The thickness of inclined tip 330 becomes thinner from the end of thickest portion 327 on the second end face 322 side toward second end face 322. The surface of inclined tip 330 forms flat surface S25.

[0041] The galvanometer mirror 32Q having the above-described shape can be formed by chamfering the rectangular parallelepiped synthetic quartz plate 320Q shown in Figure 11 in the same manner as the sapphire glass plate 320S shown in Figures 6A and 6B, and further chamfering the hatched region T3 in the thickness direction. In other words, the galvanometer mirror 32Q can be formed by chamfering the four corners C1 to C4 and the regions T1 to T3 in the thickness direction of the rectangular parallelepiped synthetic quartz plate 320Q.

[0042] Of the laser beams incident on the incident plane S21, a small portion that is not reflected by the reflective coating passes through the reflective coating and enters the interior of the galvanometer mirror 32Q. Because the optical absorption rate of synthetic quartz, the glass material that forms the galvanometer mirror 32Q, is nearly 0%, the galvanometer mirror 32Q transmits nearly 100% of the laser beam that enters its interior. Therefore, the galvanometer mirror 32Q generates almost no heat due to the laser beam that passes through without being reflected by the reflective coating. Therefore, there is no need to increase the size of the galvanometer mirror 32Q; a minimum size is sufficient.

[0043] The flat surfaces S22 to S25 are preferably coated with an anti-reflection coating made of a dielectric multilayer film, and the flat surfaces S22 to S25 on which the anti-reflection coating is applied have a transmittance of 98% or more for laser beams with wavelengths of 1040 nm to 1150 nm.

[0044] The attachment structure of galvanometer mirror 32Q to shaft 331 of galvanometer motor 33 is the same as the attachment structure of galvanometer mirror 32S to shaft 331 of galvanometer motor 33 shown in Fig. 7. Galvanometer mirror 32Q is fixed to fixed portion 332 by inserting the end portion on the first end face 321 side between a pair of protruding walls of fixed portion 332 and adhering with an adhesive. Galvanometer mirror 32Q is connected to shaft 331 of galvanometer motor 33, and rotation of shaft 331 rotates galvanometer mirror 32Q integrally therewith.

[0045] With the galvanometer mirror 32Q, the inertia can be significantly reduced compared to that of the rectangular parallelepiped synthetic quartz plate 320Q by chamfering the four corners C1 to C4 and the thickness direction of the regions T1 to T3. The galvanometer mirror 32Q can reduce heat generation, allowing the galvanometer mirror 32Q to be made smaller, and the smaller size can reduce the inertia. Therefore, if the laser processing machine 100 uses the galvanometer mirror 32Q as the galvanometer mirror 32, the galvanometer mirror 32 can be vibrated at a high frequency. The high frequency is, for example, 1 kHz or higher.

[0046] In the case of the galvanometer mirror 32Q, the brightness of the laser beam on the surface of the metal sheet W is set to 100% when the laser beam emitted from the galvanometer mirror 32Q is irradiated onto the metal sheet W while the galvanometer motor 33 is not driving the galvanometer mirror 32Q. It is preferable that the thickness of the thickest part 327 is set to a thickness that will result in a brightness of at least 98% when the laser beam emitted from the galvanometer mirror 32Q is irradiated onto the metal sheet W while the galvanometer motor 33 drives the galvanometer mirror 32Q and the galvanometer mirror 32Q is deformed.

[0047] The reason why galvanometer mirror 32Q, whose glass material is synthetic quartz, has inclined tip 330, which is chamfered in the thickness direction in region T3, is as follows: When galvanometer mirror 32 is vibrated, galvanometer mirror 32Q, whose glass material is synthetic quartz, is more likely to deform than galvanometer mirror 32S, whose glass material is sapphire glass. Therefore, it may be necessary to make the thickness of thickest portion 327 of galvanometer mirror 32Q thicker than that of galvanometer mirror 32S. If the thickness of thickest portion 327 of galvanometer mirror 32Q is made thicker than that of thickest portion 327 of galvanometer mirror 32S, it is preferable to provide inclined tip 330 to further reduce inertia.

[0048] <Modification of the Second Configuration Example> Figures 12 to 14 show a galvanometer mirror 32Q', which is a modification of the galvanometer mirror 32Q. Figures 12 to 14 are a perspective view, a front view, and a rear view, respectively, of the galvanometer mirror 32Q' as seen from the rear. In the galvanometer mirror 32Q', parts that are substantially the same as those in the galvanometer mirror 32Q are designated by the same reference numerals, and descriptions thereof may be omitted.

[0049] As shown in Figures 12 and 14, the galvanometer mirror 32Q' has a trapezoidal thickest portion 327' located in the center of the width direction. The surface of the thickest portion 327' is a trapezoidal flat surface S22'. By changing the rectangular thickest portion 327 and flat surface S22 of the galvanometer mirror 32Q to the trapezoidal thickest portion 327' and flat surface S22', the first side portion 328 and the second side portion 329 are respectively a first side portion 328' and a second side portion 329', and the inclined tip portion 330 is an inclined tip portion 330'. The surfaces of the first side portion 328' and the second side portion 329' are flat surfaces S23' and S24', respectively, and the surface of the inclined tip portion 330' is a flat surface S25'.

[0050] The galvanometer mirror 32Q' having the above-described shape can be formed by chamfering the four corners of the rectangular parallelepiped synthetic quartz plate 320Q, similar to the galvanometer mirror 32Q, and by chamfering a portion of the thickness to form a first side portion 328', a second side portion 329', and an inclined tip portion 330'. The attachment structure of the galvanometer mirror 32Q' to the shaft 331 of the galvanometer motor 33 is the same as the attachment structure of the galvanometer mirror 32Q to the shaft 331 of the galvanometer motor 33.

[0051] According to the galvanometer mirror 32Q', when the length L32, width W32, and thickness of the thickest part 327' are the same as the length L32, width W32, and thickness of the thickest part 327 in the galvanometer mirror 32Q, the inertia can be made smaller than that in the galvanometer mirror 32Q.

[0052] Although the galvanometer mirror 32S, whose glass material is sapphire glass, does not have the inclined tip 330, which is formed by chamfering the region T3 in the thickness direction, the inclined tip 330 may be provided to further reduce the inertia. Also, the galvanometer mirror 32Q or 32Q', whose glass material is synthetic quartz, may be configured without the inclined tip 330 or 330'.

[0053] Next, a detailed configuration example of the collimator unit 30 provided in the laser processing machine 100 will be described with reference to Figures 15 to 17. Figure 15 shows the collimator unit 30 provided in the laser processing machine 100 according to the first embodiment, and Figures 16 and 17 show the collimator unit 30 provided in the laser processing machine according to the second embodiment. Figures 15 to 17 show the case where the galvanometer mirror 32S is used as the galvanometer mirror 32.

[0054] 15 , the collimator unit 30 has a housing 30B fixed on a base 30C and a housing 30A connected to the housing 30B. The housings 30A, 30B, and the base 30C are made of metal such as aluminum or copper. The housing 30A connects the process fiber 12 and houses a collimation lens 301 at the end on the housing 30B side. The collimation lens 301 is attached to a collimation lens attachment portion 311. A cylindrical laser beam traveling path 30A1 is formed in the housing 30A. A diverging laser beam emitted from the process fiber 12 passes through the laser beam traveling path 30A1 and enters the collimation lens 301.

[0055] The housing 30B houses a galvanometer scanner unit 302. A laser beam path 30B1 is formed in the housing 30B, along which the laser beam travels. The laser beam emerges from the collimation lens 301, enters the plane of incidence S11 (first plane of incidence) of the galvanometer mirror 32a, is reflected by the plane of incidence S11, and is then reflected by the plane of incidence S11 (second plane of incidence) of the galvanometer mirror 32b. A galvanometer motor 33a is attached to the top of the housing 30B by a motor holder 33h, and the galvanometer mirror 32a is located within the laser beam path 30B1. A galvanometer motor 33b is attached to the side of the housing 30B by a motor holder 33h, and the galvanometer mirror 32b is located within the laser beam path 30B1.

[0056] The laser beam traveling path 30B1 is connected to a first transmitted light traveling path 30B2 that causes the laser beam that has passed through the galvanometer mirror 32a to travel toward the outside of the housing 30B, and a second transmitted light traveling path 30B3 that causes the laser beam that has passed through the galvanometer mirror 32b to travel toward the outside of the housing 30B.

[0057] A first damper 41 is attached to the outer surface of the housing 30B so as to close the terminal end of the first transmitted light path 30B2, and a second damper 42 is attached to the outer surface of the housing 30B so as to close the terminal end of the second transmitted light path 30B3. The first damper 41 and the second damper 42 can be formed by black plating an aluminum or copper metal plate. Examples of black plating that can be used include black Ni plating and black Cr plating. The first damper 41 and the second damper 42 preferably have an absorptivity of 70% or more in the wavelength band of the laser beam.

[0058] The first damper 41 absorbs the laser beam transmitted through the galvanometer mirror 32a and converts it into heat. The second damper 42 absorbs the laser beam transmitted through the galvanometer mirror 32b and converts it into heat. A first heat sink 43 and a second heat sink 44 are attached to the first damper 41 and the second damper 42, respectively, via a heat dissipation sheet or heat dissipation gel. The first heat sink 43 and the second heat sink 44 are in contact with or close to the first damper 41 and the second damper 42, respectively. The first heat sink 43 and the second heat sink 44 dissipate heat generated in the first damper 41 and the second damper 42, respectively.

[0059] The first damper 41 and the first heat sink 43 may be integrated, and the second damper 42 and the second heat sink 44 may be integrated. That is, the collimator unit 30 includes the first heat sink 43 and the second heat sink 44 which are separate from or integrated with the first damper 41 and the second damper 42, respectively.

[0060] The bend mirror 303 is attached to a bend mirror mounting plate 313, which is fixed to the housing 30 B. The focusing lens 304 is attached to a focusing lens mounting portion 314.

[0061] 15, the galvanometer mirror 32 is made of a glass material that transmits the laser beam that has penetrated the reflective coating and entered the interior, thereby suppressing heat generation from the galvanometer mirror 32. The laser beam that has passed through the galvanometer mirror 32 is absorbed by the first damper 41 and the second damper 42, and the first damper 41 and the second damper 42 are air-cooled by the first heat sink 43 and the second heat sink 44, so heat generation by the laser beam that has passed through the galvanometer mirror 32 does not pose a problem.

[0062] Since heat generation by the galvanometer mirror 32 can be suppressed, it is possible to reduce the size of the galvanometer mirror 32. Therefore, the laser processing machine 100 can vibrate the galvanometer mirror 32 at a high frequency.

[0063] 16 and 17, the same parts as those in Fig. 15 are denoted by the same reference numerals, and their description may be omitted. In Fig. 16, a laser beam traveling path 30B4 is formed in a housing 30B instead of the laser beam traveling path 30B1, the first transmitted light traveling path 30B2, and the second transmitted light traveling path 30B3. Galvanometer mirrors 32a and 32b are located in the laser beam traveling path 30B4.

[0064] The laser beam traveling path 30B4 has a first terminal end face B41 at a position a predetermined distance away from the galvanometer mirror 32a on the flat surfaces S12 to S14 side of the galvanometer mirror 32a. The first terminal end face B41 prevents the laser beam from traveling through the galvanometer mirror 32a. The laser beam traveling path 30B4 also has a second terminal end face B42 at a position a predetermined distance away from the galvanometer mirror 32b on the flat surfaces S12 to S14 side of the galvanometer mirror 32b. The second terminal end face B42 prevents the laser beam from traveling through the galvanometer mirror 32b.

[0065] At least the first end face B41 and the second end face B42 are black-plated. As in the first embodiment, black Ni plating or black Cr plating can be used as the black plating. By black-plating the first end face B41 and the second end face B42, the first end face B41 and the second end face B42 function as first and second dampers that absorb the laser beam. The first end face B41 and the second end face B42 preferably have an absorption rate of 70% or more in the wavelength band of the laser beam. Since it is not easy to black-plat only the first end face B41 and the second end face B42, the entire housing 30B may be black-plated.

[0066] 17 , a water channel 45 for cooling the first end face B41 and the second end face B42 is provided in the housing 30B near the first end face B41 and the second end face B42. Tubes 46a and 46b, through which cooling water flows, are connected to the water channel 45 by pipe joints 47a and 47b, respectively. The cooling water flows from a tube (e.g., tube 46a) on one side of the housing 30B through the water channel 45 to a tube (e.g., tube 46b) on the other side.

[0067] 16 and 17 , the galvanometer mirror 32 is made of a glass material that transmits the laser beam that has penetrated the reflective coating and entered the interior, thereby suppressing heat generation in the galvanometer mirror 32. The laser beam that has passed through the galvanometer mirror 32 is absorbed by the first end face B41 and the second end face B42, which function as first and second dampers. The first end face B41 and the second end face B42 are water-cooled by cooling water flowing through the water passage 45, so heat generation by the laser beam that has passed through the galvanometer mirror 32 does not pose a problem.

[0068] 16 and 17, the heat generated by the galvanometer mirror 32 can be suppressed, thereby enabling the size of the galvanometer mirror 32 to be reduced. Therefore, the laser processing machine 100 can vibrate the galvanometer mirror 32 at a high frequency.

[0069] The present invention is not limited to one or more of the above-described embodiments, and various modifications can be made without departing from the spirit and scope of the present invention.

[0070] This application claims priority based on Japanese Patent Application No. 2023-144233, filed with the Japan Patent Office on September 6, 2023, the entire disclosure of which is incorporated herein by reference.

Claims

1. A laser beam scanner comprising: a collimation lens that converts a diverging laser beam into collimated light; a galvanometer scanner unit that receives the laser beam emitted from the collimation lens and vibrates the laser beam to be irradiated onto a workpiece to be processed; and a processing head having a focusing lens that focuses the laser beam emitted from the galvanometer scanner unit and irradiates the workpiece, wherein the galvanometer scanner unit comprises: a first galvanometer mirror having a first incident plane on which the laser beam is incident and which is coated with a reflective coating, and which reflects the laser beam that is incident on the first incident plane; a first galvanometer motor that drives to rotate the first galvanometer mirror; a second galvanometer mirror having a second incident plane on which the laser beam is incident and which is coated with a reflective coating, and which reflects the laser beam that is incident on the second incident plane; and a second galvanometer motor that drives to rotate the second galvanometer mirror, the first and second galvanometer mirrors are formed of a glass material that transmits a portion of the laser beam that is incident on the first and second incident planes and that is not reflected by the reflective coating but penetrates the reflective coating to enter the interior of the laser processing machine; and the laser processing machine further comprises first and second dampers that absorb the laser beam that has transmitted through the first and second galvanometer mirrors.

2. The laser processing machine according to claim 1, wherein a housing that houses the galvanometer scanner unit is formed with a laser beam traveling path that propagates a laser beam that is emitted from the collimation lens, enters the first incident plane, is reflected by the first incident plane, enters the second incident plane, and is reflected by the second incident plane, and first and second transmitted light traveling paths that are connected to the laser beam traveling path and propagate the laser beam that has passed through the first and second galvanometer mirrors toward the outside of the housing, and the first and second dampers are attached to the outer surface of the housing so as to close the ends of the first and second transmitted light traveling paths, respectively.

3. A laser processing machine according to claim 2, further comprising first and second heat sinks which are separate from or integral with said first and second dampers, respectively.

4. The laser processing machine according to claim 1, wherein a housing for accommodating the galvanometer scanner unit is provided with a laser beam path for propagating a laser beam which is emitted from the collimation lens, enters the first incident plane, is reflected by the first incident plane, enters the second incident plane, and is reflected by the second incident plane, and the laser beam path has first and second terminal faces which impede the propagation of the laser beam which has passed through the first and second galvanometer mirrors, respectively, and at least the first and second terminal faces are black-plated, so that the first and second terminal faces function as the first and second dampers.

5. A laser processing machine according to claim 4, wherein the housing has water passages near the first and second end faces for cooling the first and second end faces.

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