JP2018043256A - Laser machining device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laser machining device capable of emitting laser beams having optimal BPP according to various kinds of workpieces.SOLUTION: A laser machining device includes: a laser oscillator; a plurality of optical paths through which laser beams emitted from the laser oscillator pass; a beam optical path switching part which guides the laser beams emitted from the laser oscillator to one selected from the plurality of optical paths; a plurality of process fibers respectively disposed in the plurality of optical paths; and a plurality of condenser lenses disposed in the plurality of optical paths so as to correspond to each of the plurality of process fibers, condensing the laser beams and guiding the beams to corresponding process fibers. The plurality of condenser lenses have focal distances different from each other; and each of the plurality of process fibers has a core diameter according to the focal distance of the corresponding condenser lens.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a laser processing apparatus, and more particularly to a laser processing apparatus that guides a laser beam through a process fiber.

  Laser light oscillated by a laser oscillator is excellent in monochromaticity and directivity, and is coherent, so it is used for various industrial processes such as cutting, drilling, welding, surface treatment, and marking. ing.

  A conventional laser processing apparatus will be described with reference to FIG. FIG. 6 is a perspective view schematically showing the configuration of the laser processing apparatus. In the figure, members having the same configuration and function are denoted by the same reference numerals.

The laser processing apparatus 2000 includes a laser oscillator 2100, a beam optical path switching unit 2200 that switches an optical path of the laser beam LB ₁₀₀ emitted from the laser oscillator 2100, and a plurality of process fibers 2300 (2300a to 2300c) on which the laser beam LB ₁₀₀ is incident. And comprising. The inside of the beam optical path switching unit 2200 is, for example, an atmospheric atmosphere. In the beam optical path switching unit 2200, the laser beam LB ₁₀₀ is propagated using the atmosphere as a medium. One end of the process fiber 2300 is connected to the beam optical path switching unit 2200, and the laser beam LB ₁₀₀ is incident on the process fiber 2300 through the beam optical path switching unit 2200. The process fiber 2300 is a medium for propagating the laser beam LB ₁₀₀ from the beam optical path switching unit 2200 to the vicinity of the workpiece (workpiece W).

Usually, a plurality of processing heads 2400 (three in the illustrated example) are connected to one laser oscillator 2100. Beam path switching unit 2200 switches the optical path of the laser beam _{LB 100,} guiding the laser beam _{LB 100} in any of a plurality of processes fibers 2300 (2300a~2300c). The laser beam LB ₁₀₀ guided to the inside of the process fiber 2300 eventually reaches the processing head 2400 connected to the other end of the process fiber 2300. In this way, laser processing is performed on a plurality of workpieces W while switching the processing head 2400 to which the laser beam LB ₁₀₀ is guided by the beam optical path switching unit 2200 and performing time sharing. Normally, the core diameter of each process fiber 2300 and the optical conditions (for example, refractive index) from the beam optical path switching unit 2200 to the tip of each processing head 2400 are equal to each other. Laser processing is performed under conditions. Hereinafter, the laser beam LB irradiated to the workpiece W from the machining head 2400 is referred to as LB ₄₀₀ .

  Regarding switching of the beam optical path, Patent Document 1 teaches a method of changing the optical path of a laser beam by a polarizing means such as a prism. Patent Document 2 proposes a method in which the arrangement of process fibers is changed and laser beams are incident on different process fibers.

The processing head 2400 includes a collimator lens 2410 and a condenser lens 2420. The density of the laser beam LB ₄₀₀ that has reached the processing head 2400 is increased by the condensing lens 2420, and the work W is irradiated. The workpiece W is fixed on the processing table 2500. On the other hand, the machining head 2400 can be moved by an X-axis motor 2710 and a Y-axis motor 2720, and predetermined machining is performed while the machining head 2400 is moved relative to the workpiece W. The laser oscillator 2100, the X-axis motor 2710, and the Y-axis motor 2720 are controlled by the machining control unit 2600, and the states are synchronized with the machining control unit 2600.

Special table 2014-509263 gazette JP 2012-24782 A

In order to efficiently process the workpiece W with high accuracy, BPP (Beam Parameter Product) of the laser beam LB ₄₀₀ irradiated onto the workpiece W is a point.
BPP is a parameter generally used for expressing the quality of the laser beam LB. BPP is determined by the product of the beam half-angle θ (milliradian, mrad) and the beam radius w (millimeter, mm) at the focal point (beam waist). The laser beam LB having a small BPP can be condensed so as to have a smaller beam diameter and a short focal depth. On the other hand, the laser beam LB having a large BPP has a large beam diameter and can be condensed so that the depth of focus becomes long. Therefore, for example, a laser beam LB with a small BPP is suitable for cutting a thin workpiece W, and a laser beam LB with a large BPP is suitable for cutting a thick workpiece W. That is, BPP is one of the important parameters for improving processing accuracy and productivity. The depth of focus is a range in which the beam diameters are considered to be optically the same, and specifically, a range (Rayleigh range) until the beam diameter expands to 2√2 times the beam radius. .

However, in the conventional laser processing apparatus, the BPP of the laser beam LB ₄₀₀ cannot be changed according to the workpiece W or processing conditions, and the processing accuracy and productivity are likely to decrease.

  According to one aspect of the present invention, a laser oscillator, a plurality of optical paths through which a laser beam emitted from the laser oscillator passes, and the laser beam emitted from the laser oscillator are selected from the plurality of optical paths. A beam optical path switching unit for guiding light, a plurality of process fibers respectively disposed in the plurality of optical paths, and disposed in the plurality of optical paths so as to correspond to each of the plurality of process fibers; A plurality of condensing lenses for condensing and guiding the corresponding process fibers, the plurality of condensing lenses having different focal lengths, and the plurality of process fibers respectively corresponding It is a laser processing apparatus which has a core diameter according to the focal length of the condensing lens.

  According to another aspect of the present invention, a laser oscillator, a plurality of optical paths through which a laser beam emitted from the laser oscillator passes, and the laser beam emitted from the laser oscillator are selected from the plurality of optical paths. A beam optical path switching unit that guides light to the plurality of optical fibers, a plurality of process fibers disposed in the plurality of optical paths, and a plurality of process fibers disposed to correspond to the plurality of process fibers, and the laser beam A plurality of condensing lenses that condense the light and guide it to the corresponding process fiber, and the laser beams of the plurality of corresponding process fibers respectively enter from the focal positions of the plurality of condensing lenses. The incident distances to the incident ends are different from each other, and each of the plurality of process fibers has a corresponding incident distance from the corresponding focal position. Having a core diameter corresponding to a laser processing apparatus.

  According to the laser processing apparatus of the present invention, since it is possible to irradiate a laser beam having an optimum BPP corresponding to various workpieces, laser processing with excellent processing accuracy and productivity becomes possible.

It is a perspective view which shows typically the structure of the laser processing apparatus which concerns on this invention. It is a top view which shows typically the internal structure of a beam optical path switching part. It is the side view which looked at the beam optical path switching part of FIG. 2 from the AA surface side. It is the side view which looked at the beam optical path switching part of FIG. 2 from the BB surface side. It is the side view which looked at the beam optical path switching part of Drawing 2 from the CC plane side. It is the side view which looked at the beam optical path switching part of FIG. 2 from the DD surface side. It is a top view which shows typically the internal structure of another beam optical path switching part. It is the side view which looked at the beam path switching part of FIG. 4 from the AA surface side. It is the side view which looked at the beam optical path switching part of Drawing 4 from the BB surface side. It is the side view which looked at the beam optical path switching part of Drawing 4 from the CC plane side. It is the side view which looked at the beam optical path switching part of Drawing 4 from the DD plane side. It is a perspective view which shows typically the structure of the conventional laser processing apparatus. It is a graph showing the relationship between the thickness of a workpiece | work, and a cutting speed.

  FIG. 7 shows a graph representing the relationship between the thickness and the cutting speed when a workpiece (stainless steel plate) is cut using three types of laser beams LB. The laser beam LB is emitted from a laser oscillator with an output of 4 kW, and its BPP is 4 mm · mrad, 6 mm · mrad, and 8 mm · mrad, respectively. As can be seen from this graph, the cutting speed is affected by the BPP of the laser beam LB and the thickness of the workpiece. For example, when the thickness of the workpiece is less than 5 mm, when the laser beam LB having a BPP of 4 mm · mrad is used, the cutting speed is higher than that of the laser beam LB having another BPP. When the thickness of the workpiece is about 5 to 18 mm, when the laser beam LB having a BPP of 6 mm · mrad is used, the cutting speed is faster than the laser beam LB having another BPP. When the thickness of the workpiece exceeds 18 mm, when the laser beam LB having the BPP of 8 mm · mrad is used, the cutting speed becomes faster than the laser beam LB having the other BPP.

6, when the workpiece W is irradiated with the laser beam LB ₄₀₀ emitted from the process fiber 2300, the BPP of the laser beam LB ₄₀₀ is the half angle θ and the core diameter of the process fiber 2300 × It can be expressed as a product of 1/2. That is, in order to irradiate the workpiece W with the laser beam LB ₄₀₀ having a small BPP, the process fiber 2300 having a small core diameter may be used. On the other hand, in order to irradiate the workpiece with the laser beam LB ₄₀₀ having a large BPP, a process fiber 2300 having a large core diameter may be used. However, as described above, the core diameters of the process fibers arranged in the laser processing apparatus 2000 are the same. The core of the process fiber 2300 is a region where the refractive index of the laser beam LB is the highest in the process fiber 2300, and the core diameter is a diameter in a cross section perpendicular to the longitudinal direction of the process fiber 2300 of the core.

Usually, the laser beam LB is once condensed by a condenser lens (not shown) and then guided to the process fiber 2300. Therefore, the BPP of the laser beam LB ₄₀₀ is incident on the condenser lens, and then the laser beam LB incident on the process fiber 2300 has a beam radius at the focal point of the condenser lens and a half angle θ of the beam spread (that is, the process fiber). 2300) and the core diameter of the process fiber 2300 through which the laser beam LB propagates. Therefore, in the present embodiment, the two parameters are changed according to the workpiece or machining conditions.

  The laser processing apparatus of the present embodiment guides a laser oscillator, a plurality of optical paths through which a laser beam emitted from the laser oscillator passes, and a laser beam emitted from the laser oscillator to one selected from the plurality of optical paths. Beam optical path switching unit, multiple process fibers arranged in multiple optical paths, and multiple optical paths so as to correspond to each of multiple process fibers, condensing laser beam A plurality of condensing lenses for guiding light to the process fiber.

  In the first embodiment of the laser processing apparatus, the plurality of condensing lenses have different focal lengths, and the plurality of process fibers each have a core diameter corresponding to the focal length of the corresponding condensing lens. When the focal length is different, the beam diameter at the focal point of the laser beam LB (hereinafter referred to as the focal beam diameter Dbf) changes. The beam optical path switching unit selects one of the combinations of a plurality of condensing lenses and process fibers that can obtain a beam diameter corresponding to the workpiece W or BPP suitable for processing conditions, and switches the optical path of the laser beam LB. The laser beam LB condensed by the condenser lens is incident on the corresponding process fiber at the focal position.

  In the second embodiment of the laser processing apparatus, the incident distances from the focal positions of the plurality of condenser lenses to the incident ends where the laser beams of the plurality of process fibers respectively corresponding to the plurality of condenser lenses are incident are different from each other. Each of the plurality of process fibers has a core diameter corresponding to the incident distance from the corresponding focal position. When the incident distance changes, the beam diameter of the laser beam LB at the incident end of the process fiber (that is, the beam diameter when entering the process fiber, hereinafter referred to as the incident beam diameter Dbi) changes. The beam optical path switching unit selects one of the combinations of a plurality of condensing lenses and process fibers that can obtain a beam diameter corresponding to the workpiece W or BPP suitable for processing conditions, and switches the optical path of the laser beam LB.

  With the above configuration, the laser beam LB having BPP suitable for the workpiece W can be emitted from the machining head. Therefore, the processing accuracy and productivity of laser processing are improved.

[First Embodiment]
The first embodiment will be described below with reference to FIGS. 1 to 3D. FIG. 1 is a perspective view schematically showing the configuration of the laser processing apparatus of the present embodiment. FIG. 2 is a plan view schematically showing an internal configuration of the beam optical path switching unit. 3A is a side view of the beam optical path switching unit of FIG. 2 as viewed from the AA plane side. 3B to 3D are side views of the beam optical path switching unit of FIG. 2 as viewed from the BB plane, the CC plane, and the DD plane, respectively. In the figure, members having the same configuration and function are denoted by the same reference numerals.

As shown in FIGS. 1 and 2, the laser processing apparatus 1000 according to this embodiment includes a laser oscillator 100, a plurality of optical paths through which the laser beam LB ₁ emitted from the laser oscillator 100 passes, and a plurality of process fibers 300. (310 to 330), a plurality of second condensing lenses 220 (221 to 223) for condensing the laser beam LB ₁ and guiding it to the corresponding process fiber 300, and a beam for switching the optical path of the laser beam LB ₁ 200 A of optical path switching parts. Any one of the process fibers 300 and the corresponding second condenser lens 220 are disposed in the optical path.

The laser oscillation mechanism of the laser oscillator 100 is not particularly limited, and includes a semiconductor laser using a semiconductor as a laser oscillation medium, a gas laser using a gas such as carbon dioxide (CO ₂ ) as a medium, a solid-state laser using YAG, or the like. Can be mentioned. Among these, a semiconductor laser is preferable in terms of excellent light quality and oscillation efficiency.

The inside of the beam optical path switching unit 200 is, for example, an atmospheric atmosphere, and the laser beam LB ₁ is propagated through the beam optical path switching unit 200 using the atmosphere as a medium. One end of the process fiber 300 is connected to the beam optical path switching unit 200, and the laser beam LB ₁ is reflected and collected in the beam optical path switching unit 200 and then enters the process fiber 300. The process fiber 300 is a medium for propagating the laser beam LB to the vicinity of the workpiece W. Hereinafter, referred to laser beam LB that enters the process the fiber 300 and the laser beam LB ₂ refers to the laser beam LB emitted from the process the fiber 300 with the laser beam LB _3, the laser beam LB of the laser beam LB ₄ emitted from the machining head 400 (See FIGS. 1 and 2).

Usually, a plurality of processing heads 400 (three in the illustrated example) are connected to one laser oscillator 100. The beam optical path switching unit 200 switches the reflection position of the laser beam LB ₁ and focuses it, and then guides the focused laser beam LB ₂ to one of the plurality of process fibers 300 (300a to 300c). . The laser beam LB ₃ propagated inside the process fiber 300 eventually reaches the processing head 400 connected to the other end of the process fiber 300. In this way, the optical path is switched by the beam optical path switching unit 200 and the laser beam LB ₁ is distributed to the plurality of processing heads 400, so that laser processing is performed on the plurality of workpieces W while performing time sharing. Is done.

The processing head 400 includes a collimator lens 410 and a first condenser lens 420. The density of the laser beam LB ₃ that has reached the processing head 400 is increased by the first condenser lens 420 and is irradiated onto the workpiece W. The workpiece W is fixed on the processing table 500. On the other hand, the machining head 400 can be moved by an X-axis motor 710 and a Y-axis motor 720, and predetermined machining is performed while moving the machining head 400 relative to the workpiece W. The laser oscillator 100, the beam optical path switching unit 200, the X-axis motor 710, and the Y-axis motor 720 are controlled by the processing control unit 600, and the states are synchronized with the processing control unit 600. The beam optical path switching unit 200 may be controlled by another control unit (not shown) controlled by the processing control unit 600. For example, the processing control unit 600 selects a process fiber 300 for guiding the laser beam LB _2, transmits the signal to the other control unit. Then, another control unit that has received this signal may control the beam optical path switching unit 200.

When cutting or drilling the workpiece W by the laser processing apparatus 1000 (hereinafter, collectively referred to as laser cutting), the processing head 400, the high-pressure gas (high pressure on the laser beam LB ₄ coaxial to the workpiece W oxygen, nitrogen, A gas hole for spraying air or the like and a gas path for supplying high-pressure gas to the gas hole are disposed (none of which is shown). In laser cutting, the workpiece W is cut or drilled while part of the workpiece W melted by the laser beam LB ₄ is removed by high-pressure gas.

When two or more workpieces W are welded by the laser processing apparatus 1000 (laser welding), the processing head 400 has a gas hole for blowing an inert gas (argon, helium, etc.) to the workpiece W at a low pressure, and the gas hole. A gas path for supplying an inert gas is arranged in each (not shown). The workpieces W are welded together while the oxidation of the workpiece W melted by the laser beam LB _{4 is} suppressed by an inert gas. May be surface treated workpiece W by the laser processing apparatus 1000, similar to the above, irradiates the workpiece W, the laser beam LB ₄ while blowing an inert gas. When marking the workpiece W by the laser processing apparatus 1000 is irradiated to the workpiece W, the laser beam LB ₄ while blowing gas in accordance with the desired color.

Next, the switching mechanism of the beam optical path switching unit 200 will be described with reference to FIG. 2 and FIGS. 3A to 3D.
Beam path switching unit 200, a plurality of second reflecting mirror 210 and (210a-210c), a second condenser lens for light focusing the laser beam LB ₁ that is reflected, respectively, by the second reflecting mirror 210 220 (221 and 222 223). The laser beam LB ₁ emitted from the laser oscillator 100 passes through the light guide path 250 and enters the beam optical path switching unit 200.

Each of the second reflecting mirrors 210 includes a stepping motor 230 (230a to 230c), and rotates by driving the stepping motor 230. The initial state of the second reflecting mirror 210, i.e., when not energized stepping motor 230, the second reflecting mirror 210 is in the reflecting position for reflecting the laser beam LB _1. When the stepping motor 230 is energized, the second reflecting mirror 210 rotates to a passing position where the laser beam LB ₁ passes as it is (see FIGS. 3A to 3D). Beam path switching unit 200, by energizing the at least one of the plurality of stepping motors 230, or to both without energization, it switches the reflection position of the laser beam LB _1. When all the stepping motors 230 are energized, the laser beam LB ₁ is not guided to the process fiber 300 but is incident on the beam absorber 240.

  The second condenser lenses 220 (221, 222, 223) have different focal lengths Df. The focal length Df affects the focal beam diameter Dbf of the laser beam LB. For example, when the focal length Df of the condenser lens is short, the focal beam diameter Dbf is small.

The laser beam LB ₂ collected by the second condenser lens 220 enters the process fiber 300. At this time, the 2nd reflective mirror 210, the 2nd condensing lens 220, and the process fiber 300 are arrange | positioned so that it may respond | correspond one-to-one. For example, as shown in FIGS. 3B to 3D, the laser beam LB _1a reflected by the second reflecting mirror 210a is condensed by the second condenser lens 221 and enters the process fiber 310. Similarly, the laser beam LB _1b reflected by the second reflecting mirror 210b is condensed by the second condenser lens 222 and enters the process fiber 320. The laser beam LB _1c reflected by the second reflecting mirror 210c is condensed by the second condenser lens 223 and enters the process fiber 330. Each process fiber 300, the second condenser lens 220 is a laser beam LB ₂ which is condensed, and is arranged to be incident at the focal position.

The plurality of process fibers 300 (310, 320, 330) have different core diameters. The core diameter of the process fiber 300 is determined according to the focal length Df (that is, the focal beam diameter Dbf). For example, the core diameter of the process fiber 300 is preferably 115 to 140% of the focal beam diameter Dbf. This makes it easier to obtain a desired BPP of the laser beam LB ₄ , reduces energy loss when the laser beam LB ₂ enters the process fiber 300, and improves productivity.

The core of the process fiber 300 is a region where the refractive index of the laser beam LB ₂ is the highest in the process fiber 300. In the core, the laser beam LB ₂ is totally reflected and confined in the process fiber 300. The core diameter is a diameter in a cross section perpendicular to the longitudinal direction of the process fiber 300 of the core. Usually, the core is formed along the longitudinal center line of the process fiber 300, and a region (clad) having a lower refractive index is formed around the core. Therefore, the laser beam LB ₂ introduced into the core does not enter the clad, while a part of the laser beam LB ₂ introduced into the clad can enter the core. The clad may be formed of a plurality of regions having different refractive indexes. In this case, the refractive index decreases toward the outside of the process fiber 300.

The BPP of the laser beam LB ₄ depends on the BPP of the laser beam LB ₃ immediately after being emitted from the process fiber 300. The BPP of the laser beam LB ₃ can be represented by the product of the half angle θ and the core diameter of the process fiber 300 × ½. That is, by guiding the laser beam LB ₂ having a large focal beam diameter Dbf to the process fiber 300 having a large core diameter suitable for the focal beam diameter Dbf, the laser beam LB ₃ having a large BPP can be obtained. As a result, the BPP of the laser beam LB ₄ is increased. On the other hand, in case of irradiation with a small laser beam LB ₄ of BPP the workpiece W, using a smaller process fiber 300 having a core diameter of, for guiding the laser beam LB ₂ having a small focal beam diameter Dbf there.

When the focal length Df ₁ of the second condenser lens 221 is 100 mm, when the laser beam LB ₁ having a beam diameter of 20 mm is condensed, the focal beam diameter Dbf of the laser beam LB ₂ is about 80 μm. Therefore, the core diameter of the process fiber 310 is set to about 100 μm, and the laser beam LB ₂ is incident thereon. The BPP of the laser beam LB ₄ emitted from the process fiber 310 is about 4 mm · mrad.

When the focal length Df ₂ of the second condenser lens 222 is 200 mm, when the laser beam LB ₁ is condensed, the focal beam diameter Dbf of the laser beam LB ₂ is about 160 μm. Therefore, the core diameter of the process fiber 320 is set to about 200 μm, and the laser beam LB ₂ is incident thereon. The BPP of the laser beam LB ₄ emitted from the process fiber 320 is about 8 mm · mrad.

When the focal length Df ₃ of the second condenser lens 223 is 300 mm, when the laser beam LB ₁ is condensed, the focal beam diameter Dbf of the laser beam LB ₂ is about 240 μm. Therefore, the core diameter of the process fiber 330 is set to about 300 μm, and the laser beam LB ₂ is incident thereon. The BPP of the laser beam LB ₄ emitted from the process fiber 330 is about 12 mm · mrad.

As described above, in the present embodiment, a plurality of second condenser lenses 220 having different focal lengths Df are arranged in the optical path from the laser oscillator 100 to the process fiber 300, and the focal lengths of the second condenser lenses 220 are arranged. A plurality of process fibers 300 having a core diameter corresponding to Df are arranged. Accordingly, it is possible to appropriately switch the optical path of the laser beam LB ₁ emitted from one laser oscillator and generate a plurality of laser beams LB ₄ having different BPPs. As a result, the workpiece W can be laser machined using the laser beam LB having BPP corresponding to the machining content, the thickness and material of the workpiece W, the machining shape, and the like.

[Second Embodiment]
In the second embodiment, focal positions F of the plurality of second condenser lenses 220 and incident ends of the plurality of process fibers 300 corresponding to the plurality of second condenser lenses 220, respectively, on which the laser beams LB are incident, Are different from each other (incident distance Di). Therefore, the incident beam diameter Dbi of the laser beam LB ₂ incident on the process fiber 300 varies depending on the combination of the second condensing lens 220 and the process fiber 300 that pass through. Furthermore, the core diameters of the plurality of process fibers 300 are different from each other so as to correspond to the incident beam radius Dbi by the second condenser lens 220 corresponding thereto. Therefore, the BPP of the laser beam LB ₃ emitted from the process fiber 300, and consequently the BPP of the laser beam LB ₄ emitted from the processing head 400 can be changed efficiently.

  Hereinafter, the present embodiment will be described with reference to FIGS. 4 to 5D. FIG. 4 is a plan view schematically showing the internal configuration of the beam optical path switching unit. 5A is a side view of the beam optical path switching unit of FIG. 4 as viewed from the AA plane side. 5B to 5D are side views of the beam path switching unit of FIG. 4 as viewed from the BB plane, CC plane, and DD plane, respectively. In the figure, members having the same configuration and function are denoted by the same reference numerals. Note that the laser oscillator 100, the process fiber 300, the processing head 400, the processing table 500, and the processing control unit 600 have the same configuration as that of the first embodiment, for example. The configuration or operation of the second reflecting mirror 210 and the stepping motor 230 may also be the same as in the first embodiment. The optical properties (including the focal length) of each second condenser lens 220 may be the same or different. Hereinafter, a case where the plurality of second condenser lenses 220 all have the same optical properties will be described as an example.

  The plurality of second condenser lenses 220 and the plurality of process fibers 300 corresponding thereto are arranged so that the incident distances Di are different from each other. For example, as described above, when the optical properties of the second condenser lenses 220a to 220c are the same, the incident ends 300t of the plurality of process fibers 300 corresponding to the plurality of second condenser lenses 220 are used. The physical distances up to are different from each other. In FIG. 4, each 2nd condensing lens 220 is fixed, and the position of the incident end of process fiber 310-330 is each changed and arrange | positioned.

In the illustrated example, the process fiber 310 is disposed so that the incident end 310 t thereof coincides with the focal position F of the second condenser lens 221. Therefore, the incident beam diameter Dbi when entering the process the fiber 310 of the laser beam LB ₂ is the same as the focal beam diameter DBF. On the other hand, the incident ends (320t, 330t) of the process fibers 320 and 330 do not coincide with the focal position F of the corresponding second condenser lens (222, 223). That is, the laser beam LB ₂ is incident on the process fiber 320 or the process fiber 330 in a defocused state. Therefore, the beam diameter when entering the process the fiber 320 or process fiber 330 of the laser beam LB ₂ (incident beam diameter Dbi) is greater than the focal beam diameter DBF.

For example, if the focal length Df both the 100mm of the second condenser lens 220a-c, when focusing the laser beam LB ₁ having a beam diameter of 20 mm, the focal point the beam diameter Dbf is about 80μm at the focal position F . When placing the process fiber 310 as described above, that is, when the incident distance Di ₁ to place the process fiber 310 so that the 0 mm, by focusing the laser beam LB ₁ at the second condenser lens 220a, The incident beam diameter Dbi of the laser beam LB ₂ when entering the process fiber 310 is the same as the focal beam diameter (about 80 μm).

When the process fiber 320 is arranged so that the incident distance Di is 80 mm, the laser beam LB ₂ is incident when the laser beam LB ₁ is condensed by the second condenser lens 220 b and incident on the process fiber 320. The beam diameter Dbi is about 160 μm. When the process fiber 330 is arranged so that the incident distance Di is 60 mm, the laser beam LB ₂ is incident when the laser beam LB ₁ is condensed by the second condenser lens 220 c and incident on the process fiber 330. The beam diameter Dbi is about 240 μm.

Similarly, in this embodiment, the core diameters of the plurality of process fibers 300 are different from each other. The core diameter of the process fiber 300 is determined according to the incident distance Di (that is, the incident beam diameter Dbi). For example, the core diameter of the process fiber 300 is preferably 115 to 140% of the incident beam diameter Dbi. This makes it easier to obtain a desired BPP of the laser beam LB ₄ , reduces energy loss when the laser beam LB ₂ enters the process fiber 300, and improves productivity.

In the above case, the core diameter of the process fiber 310 may be the smallest, for example, about 100 μm. The BPP of the laser beam LB ₄ emitted from the process fiber 310 is about 4 mm · mrad. The core diameter of the process fiber 330 may be the largest, for example, about 300 μm. The BPP of the laser beam LB ₄ emitted from the process fiber 330 is about 12 mm · mrad. The core diameter of the process fiber 320 may be about 200 μm, for example. The BPP of the laser beam LB ₄ emitted from the process fiber 320 is about 8 mm · mrad.

As described above, in the present embodiment, the second condenser lens 220 and the process fiber 300 are arranged so that the incident distance Di is different, and the core diameter of the arranged process fiber 300 is set to the second condenser lens. According to the incident beam diameter Dbi of the laser beam LB ₂ condensed at 220. Thus, even when the second optically same condensing lens is used, the optical path of the laser beam LB ₁ emitted from one laser oscillator is switched as appropriate, and a plurality of laser beams LB _{4 having} different BPPs are used. Can be generated. As a result, the workpiece W can be laser machined using the laser beam LB having BPP corresponding to the machining content, the thickness and material of the workpiece W, the machining shape, and the like.

  According to the laser processing apparatus of the present invention, it is possible to emit a laser beam according to the processing content, the thickness and material of the workpiece, the processing shape, and the like, so that the processing accuracy and productivity are improved and high versatility is provided.

1000: Laser processing apparatus 100: Laser oscillator 200, 200A, 200B: Beam optical path switching unit 210, 210a-210c: Second reflection mirror 220, 220a-220c, 221, 222, 223: Second condenser lens 230, 230a- 230c: Stepping motor 240: Beam absorber 250: Light guide path 300, 310, 320, 330: Process fiber 300t, 310t, 320t, 330t: Incident end 400: Processing head 410: Collimator lens 420: First condenser lens 500: Processing Table 600: Processing control unit 710: X-axis motor 720: Y-axis motor 2000: Laser processing device 2100: Laser oscillator 2200: Beam optical path switching unit 2210, 2210a to 2210c: Reflection mirrors 2220, 2221 to 22 3: condenser lens 2300,2300A～2300c: Process Fiber 2400: machining head 2410: a collimator lens 2420: condensing lens 2500: processing table 2600: processing control unit 2710: X-axis motor 2720: Y-axis motor

Claims (2)

A laser oscillator;
A plurality of optical paths through which a laser beam emitted from the laser oscillator passes;
A beam optical path switching unit for guiding the laser beam emitted from the laser oscillator to one selected from the plurality of optical paths;
A plurality of process fibers respectively disposed in the plurality of optical paths;
A plurality of condensing lenses disposed in the plurality of optical paths so as to correspond to the plurality of process fibers, respectively, condensing the laser beam and guiding the laser beams to the corresponding process fibers,
The plurality of condensing lenses have different focal lengths;
The laser processing apparatus, wherein each of the plurality of process fibers has a core diameter corresponding to the focal length of the corresponding condensing lens. A laser oscillator;
A plurality of optical paths through which a laser beam emitted from the laser oscillator passes;
A beam optical path switching unit for guiding the laser beam emitted from the laser oscillator to one selected from the plurality of optical paths;
A plurality of process fibers disposed in the plurality of optical paths;
A plurality of condensing lenses disposed in the plurality of optical paths so as to correspond to the plurality of process fibers, respectively, condensing the laser beam and guiding the laser beams to the corresponding process fibers,
The incident distances from the focal positions of the plurality of condenser lenses to the incident ends on which the laser beams of the plurality of corresponding process fibers are incident are different from each other,
The laser processing apparatus, wherein each of the plurality of process fibers has a core diameter corresponding to the incident distance from the corresponding focal position.

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