Laser irradiation device, laser processing apparatus including same, and laser processing method

Abstract

[Problem] To provide: a laser irradiation device capable of inhibiting scattering of spatter while cutting even a plated metal sheet; a laser processing apparatus including the same; and a laser processing method. [Solution] The present invention relates to: a laser irradiation device 10 for cutting, with laser light, a plated metal sheet obtained by forming a plating film on a surface of a metal sheet; a laser processing apparatus 100 including said laser irradiation device; and a laser processing method. The laser irradiation device 10 comprises a laser head 2 having a built-in lens for collecting the laser light, and a laser oscillator 3 for introducing the laser light into the laser head 2, and irradiates the plated metal sheet with round small-diameter laser light 21a, 21b and large-diameter laser light 22a, 22b having diameters larger than those of the small-diameter laser light 21a, 21b, as the laser light. Said irradiation with the large-diameter laser light 22a, 22b breaks the plating film, and said irradiation with the small-diameter laser light 21a, 21b cuts the metal sheet.

Description

Laser irradiation device, laser processing device equipped with the same, and laser processing method

[0001] The present invention relates to a laser irradiation device for cutting a plated metal sheet with laser light, a laser processing device including the same, and a laser processing method.

[0002] Laser processing is known as one method for cutting metal plates, in which a metal plate is irradiated with laser light from a laser head and the metal plate is cut by the energy of the irradiated laser.

[0003] For example, in the field of press processing, laser processing is used when cutting a long coiled metal plate into a desired shape or when cutting a metal plate as a blank into a desired shape. Laser processing has the advantage that the metal plate can be precisely cut into the desired shape by preprogramming the cutting area along which the laser head travels, eliminating the need for a cutting die. Laser processing also has the advantage of being less likely to produce burrs.

[0004] An example of a laser processing device is a laser blanking device that cuts flat plate material into blanks using laser light emitted from a laser nozzle (laser head) while conveying the material, and that includes a laser nozzle, an endless conveyor for transporting the plate material, a pair of upstream and downstream support rollers provided below the laser nozzle, and retraction rollers provided below the upstream and downstream support rollers, where the upstream support roller, downstream support roller, and retraction roller guide the endless conveyor and are each independently positionable (see, for example, Patent Document 1).

[0005] The conveyor belt further includes a first endless belt on the front side and a second endless belt on the rear side, a first front upper inner guide roller, a first front lower inner guide roller, a first rear upper inner guide roller, a first rear middle inner guide roller, a first rear lower inner guide roller, a first guide portion, a second front upper inner guide roller, a second front middle inner guide roller, a second front lower inner guide roller, a second rear upper inner guide roller, a second rear lower inner guide roller and a second guide portion that guide the belts, and a laser nozzle (laser head) disposed above a space between the first endless belt and the second endless belt, A laser blanking device is known in which a shift section, which is formed by integrating a second front upper inner guide roller and a second front middle inner guide roller, slides in accordance with the movement of the laser nozzle in the front-to-rear direction so as to be positioned directly below the laser nozzle, and a driven shift section, which is formed by integrating a first rear lower inner guide roller and a second front lower inner guide roller, is slidable along a Y-axis driven shift rail extending in the front-to-rear direction and provided on both sides of the first endless belt and the second endless belt, and moves in the opposite direction to the movement of the shift section, following the sliding of the shift section (see, for example, Patent Document 2).

[0006] Patent No. 5916170 Patent No. 6792728

[0007] However, in the laser irradiation devices equipped with the laser heads described in Patent Documents 1 and 2, when a metal plate on which a plating film is formed for the purpose of rust prevention or the like (hereinafter also referred to as a "plated metal plate") is subjected to laser processing, a situation occurs in which so-called spatter is scattered when the plated metal plate is cut. Incidentally, if the moving speed of the laser head is increased, the degree of scattering of spatter increases.

[0008] If the scattered spatter adheres to the plated metal plate, it will impair the cleanliness of the plated metal plate, and if it enters the laser head, it will cause a decrease in the intensity of the laser light emitted from the laser head.Incidentally, if a protective glass or the like is provided to prevent the spatter from entering the laser head, the protective glass will have to be replaced frequently, which will reduce the operating rate.

[0009] The present invention has been made in consideration of the above circumstances, and aims to provide a laser irradiation device that can suppress the scattering of spatter when cutting even plated metal sheets, a laser processing device equipped with the same, and a laser processing method.

[0010] The present inventors have conducted extensive research to solve the above problems, and have found that the above problems can be solved by irradiating a large-diameter laser beam and a small-diameter laser beam, destroying the plating film with the irradiation of the large-diameter laser beam and cutting the metal plate with the irradiation of the small-diameter laser beam, thereby completing the present invention.

[0011] The present invention is a laser irradiation device for cutting a plated metal plate having a plating film formed on the surface of the metal plate with laser light, and is equipped with a laser head having a built-in lens for focusing the laser light and a laser oscillator for introducing the laser light into the laser head, and is a laser irradiation device that irradiates the plated metal plate with a round small-diameter laser light and a large-diameter laser light having a diameter larger than that of the small-diameter laser light, so that the plating film is destroyed by irradiation with the large-diameter laser light and the metal plate is cut by irradiation with the small-diameter laser light.

[0012] In the laser irradiation device of the present invention, it is preferable that the large-diameter laser beam is annular and surrounds the small-diameter laser beam, the plating film is destroyed by irradiation of the large-diameter laser beam, and the metal plate is cut by irradiation of the small-diameter laser beam. Also, in the laser irradiation device of the present invention, it is preferable that the large-diameter laser beam is circular and includes the small-diameter laser beam, the plating film is destroyed by irradiation of only the large-diameter laser beam, and the metal plate is cut by simultaneous irradiation of the small-diameter laser beam and the large-diameter laser beam.

[0013] In the laser irradiation device of the present invention, it is preferred that the plated film is a zinc plated film or an aluminum plated film, the metal plate is a steel plate, the plated metal plate has a thickness of 9.0 mm or less, the output of the small-diameter laser beam is 0.5 to 15.0 kW, and the output of the large-diameter laser beam is 0.1 to 10.0 kW.

[0014] The present invention is a laser processing apparatus for cutting a plated metal sheet having a plating film formed on the surface thereof with a laser beam, the laser processing apparatus comprising the above-mentioned laser irradiation device for irradiating a laser beam and a conveyor for transporting the plated metal sheet, the laser processing apparatus cutting the plated metal sheet with the laser beam while continuously transporting the plated metal sheet. Furthermore, the laser processing apparatus of the present invention preferably further comprises a pair of Y-rails provided on both sides of the conveyor and extending in the transport direction, and an X-rail extending across the entire width of the conveyor, the laser head being guided by the X-rail for reciprocating movement, and the X-rail being guided by the Y-rail for reciprocating movement.

[0015] The present invention is a laser processing method using the above laser processing device, in which a laser head is moved along a planned cutting location of a plated metal plate while simultaneously outputting a small-diameter laser beam and a large-diameter laser beam. In this case, in the laser processing method of the present invention, the relative speed of the laser head with respect to the plated metal plate is preferably 1.0 to 150 m / min.

[0016] The laser irradiation device of the present invention irradiates a plated metal sheet with a large-diameter laser beam and a small-diameter laser beam. In addition to cutting the metal sheet with the small-diameter laser beam, the large-diameter laser beam destroys the plating film, thereby suppressing spatter scattering during cutting of the plated metal sheet. As a result, spatter scattering can be prevented from adhering to the plated metal sheet or from penetrating into the laser head. Therefore, the laser irradiation device of the present invention can suppress spatter scattering during cutting of a plated metal sheet. For example, when using a steel sheet having a zinc-plated or aluminum-plated film formed thereon and having a thickness within the above-described range, setting the output power of the small-diameter laser beam and the output power of the large-diameter laser beam within the above-described ranges can effectively suppress spatter scattering during cutting.

[0017] Here, the reason why the use of the above-mentioned laser irradiation device can suppress scattering of spatter is not clear, but it is thought that, apart from cutting the metal plate with irradiation of a small-diameter laser beam, destroying the plating film with irradiation of a large-diameter laser beam prevents the melting of the metal plate material and the vaporization of the plating film from occurring simultaneously, thereby suppressing scattering of the metal plate material as spatter due to volume expansion caused by the vaporization of the plating film. However, the reason is not limited to this.

[0018] In the laser irradiation device of the present invention, when the large-diameter laser light is annular and surrounds the small-diameter laser light, or when the large-diameter laser light is round and includes the small-diameter laser light, the plating film can be destroyed by irradiation with the large-diameter laser light just before cutting the metal plate by irradiation with the small-diameter laser light, so that the plating metal plate can be cut efficiently while suppressing the scattering of spatter.

[0019] In the laser processing apparatus of the present invention, a laser head is moved along the intended cutting area of ​​a plated metal sheet and irradiated with laser light, thereby cutting the plated metal sheet. In other words, continuous laser processing is possible, resulting in excellent production efficiency. In this case, since the laser head of the laser processing apparatus is the same as that of the laser irradiation device described above, it is possible to suppress the scattering of spatter when cutting the plated metal sheet. As a result, scattering spatter can be suppressed not only from adhering to the plated metal sheet and entering the laser head, but also from adhering to the conveyor.

[0020] The laser processing device of the present invention performs continuous laser processing while transporting the plated metal plate on a conveyor, resulting in extremely high production efficiency. Furthermore, the laser processing device is equipped with a Y-axis rail and an X-axis rail, allowing the laser head to move smoothly in all directions on a plane parallel to the plated metal plate. This allows for high-precision laser processing even when the intended cutting area has a complex shape or a smooth curve.

[0021] In the laser processing method of the present invention, by simultaneously outputting a small-diameter laser beam and a large-diameter laser beam while moving a laser head along the intended cutting location of the plated metal sheet, the plating film is destroyed first, and the metal sheet is cut immediately thereafter, thereby efficiently cutting the plated metal sheet while suppressing spatter scattering. Furthermore, in the above laser processing method, since it is sufficient to simply simultaneously output a small-diameter laser beam and a large-diameter laser beam while moving the laser head, complex control is not required, and laser processing can be performed relatively easily. In this case, by setting the relative speed of the laser head with respect to the plated metal sheet within the above range, spatter scattering can be suppressed and productivity can be improved.

[0022] Fig. 1 is a perspective view schematically illustrating a first embodiment of a laser irradiation device according to the present invention. Fig. 2(a) is a side view showing a state in which a laser head of the laser irradiation device according to the first embodiment is irradiating a laser beam, and Fig. 2(b) is a schematic cross-sectional view of the laser head shown in Fig. 2(a). Fig. 3(a) is an explanatory diagram showing the shape of a small-diameter laser beam irradiated from the laser head of the laser irradiation device according to the first embodiment when it reaches a plated metal plate, and Fig. 3(b) is an explanatory diagram showing the shape of a large-diameter laser beam irradiated from the laser head of the laser irradiation device according to the first embodiment when it reaches a plated metal plate. Fig. 4(a) is an explanatory diagram showing a cross-sectional view of the power density distribution of the laser beam on a plated metal plate when the plated metal plate is irradiated with a laser beam by the laser irradiation device according to the first embodiment, and Fig. 4(b) is an explanatory diagram showing the power density distribution of Fig. 4(a) from above. Fig. 5(a) is an explanatory diagram showing the shape of a small-diameter laser beam irradiated from a laser head of a laser irradiation device according to a second embodiment when it reaches a plated metal sheet, and Fig. 5(b) is an explanatory diagram showing the shape of a large-diameter laser beam irradiated from a laser head according to the second embodiment when it reaches a plated metal sheet. Fig. 6 is a perspective view showing an embodiment of a laser processing device according to the present invention. Figs. 7(a) to 7(d) are explanatory diagrams showing the shape of a large-diameter laser beam irradiated from a laser head of a laser irradiation device according to another embodiment when it reaches a plated metal sheet.

[0023] Preferred embodiments of the present invention will be described in detail below, with reference to the drawings as necessary. In the drawings, identical elements are designated by the same reference numerals, and duplicate explanations will be omitted. Furthermore, unless otherwise specified, positional relationships such as up, down, left, and right are based on the positional relationships shown in the drawings. Furthermore, the dimensional ratios of the drawings are not limited to those shown.

[0024] (Laser irradiation device) The laser irradiation device according to the present invention is for irradiating laser light, and more specifically, is a device for cutting a plated metal plate having a plating film formed on the surface of the metal plate with laser light. That is, in the laser irradiation device, a laser head is moved and the plated metal plate can be cut with laser light irradiated from the laser head.

[0025] Here, the shape of the plated metal sheet may be flat or three-dimensional before and after laser processing. Furthermore, the plated metal sheet may be cut to a predetermined size (so-called blank material) before laser processing, or may be a long piece wound into a coil. For example, the laser processing device may use a blank material and cut it into a desired shape to form a processed material, or may use a coil-shaped material and cut it into a blank material.

[0026] In the plated metal sheet, the material of the metal sheet is not particularly limited as long as it can be cut by laser light, and examples thereof include iron sheet, aluminum sheet, titanium sheet, steel sheet (including high-tensile steel and ultra-high-tensile steel), alloy sheets thereof, etc. Among these, steel sheet is preferably used as the material of the metal sheet from the viewpoint of its versatility and excellent strength, and from the viewpoint of being able to fully enjoy the effects of the present invention.

[0027] When the metal plate is a steel plate, the thickness of the plated metal is preferably 9.0 mm or less, and more preferably 0.4 to 9.0 mm. Since the plated film is an extremely thin film, the thickness of the metal plate itself may be within the above range. If the thickness of the plated metal plate exceeds 9.0 mm, laser processing takes longer than when the thickness is within the above range, and although the amount of scattered spatter is reduced, there is a drawback in that productivity decreases.

[0028] In plated metal sheets, the material of the plating film can be nickel, chromium, zinc, copper, gold, silver, tin, aluminum, etc. Among these, when the metal sheet is a steel sheet, it is preferable to use zinc or aluminum as the material of the plating film, which has a greater ionization tendency than iron and has excellent rust prevention effects. In other words, the plating film is preferably a zinc plating film or an aluminum plating film.

[0029] (First Embodiment of Laser Irradiation Device) Fig. 1 is a perspective view schematically showing a first embodiment of a laser irradiation device according to the present invention. As shown in Fig. 1, a laser irradiation device 10 according to the first embodiment includes a laser head 2 and a laser oscillator 3 connected to the laser head 2 via a fiber cable 4. In the laser irradiation device 10, the laser oscillator 3 is a device for introducing laser light into the laser head 2, and a known device can be used as appropriate. The laser oscillator 3 is installed at an arbitrary position outside the laser head 2. Similarly, a known device can be used as the fiber cable 4 as appropriate.

[0030] Fig. 2(a) is a side view showing a state in which the laser head of the laser irradiation device according to the first embodiment is irradiating laser light, and Fig. 2(b) is a schematic cross-sectional view of the laser head shown in Fig. 2(a). As shown in Fig. 2(b), the laser head 2 has a nozzle opening 20 at its lower end. Therefore, in the laser irradiation device 10, laser light is irradiated downward from the nozzle opening 20 of the laser head 2. The laser head 2 also has a built-in lens (not shown) for focusing the laser light introduced from the laser oscillator 3.

[0031] 2A, the laser irradiation device 10 is capable of irradiating a small-diameter laser beam 22a and a large-diameter laser beam 21a as laser beams. Note that the laser irradiation device 10 is capable of irradiating the large-diameter laser beam 21a and the small-diameter laser beam 22a simultaneously or separately from the laser head 2 by adjusting the laser beam introduced from the laser oscillator 3.

[0032] FIG. 3A is an explanatory diagram showing the shape of a small-diameter laser beam irradiated from the laser head of the laser irradiation device according to the first embodiment when it reaches a plated metal plate, and FIG. 3B is an explanatory diagram showing the shape of a large-diameter laser beam irradiated from the laser head according to the first embodiment when it reaches a plated metal plate. Note that FIGS. 3A and 3B illustrate the shape of the laser beam when it reaches the plated metal plate, and the shape of the laser beam before reaching the plated metal plate is not limited thereto. As shown in FIG. 3A, the small-diameter laser beam 22a is round (circular), and the entire circle is the laser beam. Note that such a round shape includes not only a perfect circle but also an ellipse. As shown in FIG. 3B, the large-diameter laser beam 21a is a continuous ring (donut-shaped), and the portion between the outer and inner circles is the laser beam. Furthermore, the large-diameter laser beam 21a has a larger diameter than the small-diameter laser beam 22a and forms a ring surrounding the small-diameter laser beam 22a. That is, the small-diameter laser beam 22a is irradiated inside the inner circle of the large-diameter laser beam 21a.

[0033] 4A is an explanatory diagram showing a cross-sectional view of the power density distribution of laser light on a plated metal plate when the plated metal plate is irradiated with laser light by the laser irradiation device according to the first embodiment, and FIG. 4B is an explanatory diagram showing the power density distribution of FIG. 4A from above. As shown in FIGS. 4A and 4B, in the laser irradiation device 10, the large-diameter laser light 21a is irradiated onto a relatively wide area a1 outside the small-diameter laser light 22a. This destroys the plating film on the plated metal plate. Meanwhile, the small-diameter laser light 22a is irradiated onto a relatively narrow area a2 inside the large-diameter laser light 21a. This cuts the metal plate.

[0034] In the laser irradiation device 10 according to the first embodiment, the laser head 2 irradiates the plated metal plate with laser light from the nozzle opening 20 of the laser head 2 while moving. Therefore, in the plated metal plate, the plated film is destroyed by irradiation with only the large-diameter laser beam 21a, and then the metal plate is cut by irradiation with only the small-diameter laser beam 22b. In this way, the laser irradiation device 10 destroys the plated film, which is thought to be the cause of spatter scattering, immediately before cutting, thereby efficiently cutting the plated metal plate while suppressing spatter scattering. Furthermore, since the plated film is not left in that state after energy is applied and destroyed, but is cut immediately, oxidation of the portion of the plated metal plate where the plated film is destroyed can be minimized.

[0035] In this case, the output power of the small-diameter laser beam 22a is not particularly limited as long as it can cut the metal plate, but is preferably 0.5 to 15.0 kW from the viewpoints of safety and energy cost. The output power of the large-diameter laser beam 21a is not particularly limited as long as it can destroy the plating film, but is preferably 0.1 to 10.0 kW from the viewpoints of safety and energy cost. The output power of the small-diameter laser beam 22a per unit area is preferably greater than the output power of the large-diameter laser beam 21a per unit area. For example, when a steel plate having a thickness of 9 mm or less and a zinc-plated or aluminum-plated film is used as the plated metal plate, setting the output power of the small-diameter laser beam and the output power of the large-diameter laser beam within the above ranges effectively prevents spatter from scattering during cutting.

[0036] Here, the types of the small-diameter laser light 22a and the large-diameter laser light 21a are not particularly limited, but for example, a solid-state laser, a liquid laser, a gas laser, a semiconductor laser, a free electron laser, a metal vapor laser, a chemical laser, etc. can be used.

[0037] (Second embodiment of laser irradiation device) Similar to the laser irradiation device 10 according to the first embodiment, the laser irradiation device according to the second embodiment includes a laser head 2 and a laser oscillator 3 connected to the laser head 2 via a fiber cable 4. That is, the laser irradiation device according to the second embodiment is the same as the laser irradiation device 10 according to the first embodiment except for the laser light, as will be described later.

[0038] FIG. 5A is an explanatory diagram showing the shape of a small-diameter laser beam irradiated from a laser head of a laser irradiation device according to a second embodiment when it reaches a plated metal plate, and FIG. 5B is an explanatory diagram showing the shape of a large-diameter laser beam irradiated from a laser head according to a second embodiment when it reaches a plated metal plate. Note that FIGS. 5A and 5B show the shape of the laser beam when it reaches a plated metal plate, and the shape of the laser beam before reaching the plated metal plate is not limited thereto. As shown in FIG. 5A, the small-diameter laser beam 22b is round (circular), and the entire circle is the laser beam. Note that such a round shape includes not only a perfect circle but also an ellipse. As shown in FIG. 5B, the large-diameter laser beam 21b is round (circular), and the entire circle is the laser beam. Note that such a round shape includes not only a perfect circle but also an ellipse. The large-diameter laser beam 21b has a larger diameter than the small-diameter laser beam 22b and is round so as to include the small-diameter laser beam 22b. That is, the small-diameter laser beam 22b is irradiated onto the central portion of the large-diameter laser beam 21b so as to overlap with the large-diameter laser beam 21b.

[0039] In the laser irradiation device according to the second embodiment, the laser head 2 irradiates the plated metal plate with a laser beam from the nozzle opening 20 of the laser head 2 while moving. Therefore, immediately after the plating film on the plated metal plate is destroyed by irradiation with only the large-diameter laser beam 21b, the metal plate is cut by simultaneous irradiation with the large-diameter laser beam 21b and the small-diameter laser beam 22b. In this way, the laser irradiation device destroys the plating film, which is thought to be the cause of spatter scattering, just before cutting, thereby efficiently cutting the plated metal plate while suppressing spatter scattering. Furthermore, since the plated film is not left in that state after energy is applied and cut, but is cut immediately, oxidation of the portion of the plated metal plate where the plating film is destroyed can be minimized.

[0040] Here, the range of the output power of the small-diameter laser beam 22b and the range of the output power of the large-diameter laser beam 21b are the same as those described above, and therefore, a description thereof will be omitted. Note that the output power per unit area of ​​the small-diameter laser beam 22b is preferably greater than the output power per unit area of ​​the large-diameter laser beam 21b. Furthermore, the types of the small-diameter laser beam 22b and the large-diameter laser beam 21b are the same as those described above, and therefore a description thereof will be omitted.

[0041] (Laser processing device) The laser processing device according to the present invention is a device for performing laser processing, and more specifically, is a device that moves the laser head 2 of the above-described laser irradiation device 10 while transporting a plated metal sheet, and cuts the plated metal sheet with laser light irradiated from the nozzle opening 20 of the laser head 2. The laser processing device is excellent in productivity because it can continuously perform laser processing while continuously transporting the plated metal sheet. In this specification, the "transport direction" means the transport direction of the plated metal sheet.

[0042] Fig. 6 is a perspective view showing one embodiment of a laser processing apparatus according to the present invention. It should be noted that the plated metal plate and the laser oscillator 3 are not shown in Fig. 6. As shown in Fig. 6, the laser processing apparatus 100 according to this embodiment includes a laser irradiation device 10 for irradiating the plated metal plate with laser light, a conveyor 1 for transporting the plated metal plate (not shown), and a Y-axis rail 5 and an X-axis rail 6 for moving the laser head 2.

[0043] In the laser processing apparatus 100, conveyors 1 are arranged side by side on the left and right, and the left conveyor 1 and the right conveyor 1 have the same structure. The conveyors 1 have the function of transporting the plated metal sheet in a predetermined transport direction A before and after laser processing, and the left and right conveyors 1 are driven synchronously when transporting the plated metal sheet. Note that if the plated metal sheet is small, it is also possible to drive only the conveyor 1 on one side.

[0044] The conveyor 1 is made up of an upstream conveyor 1a and a downstream conveyor 1b arranged in series. Both the upstream conveyor 1a and the downstream conveyor 1b have a belt and guide rolls that guide the belt. The upstream conveyor 1a and the downstream conveyor 1b can be driven independently.

[0045] In the conveyor 1, a gap S is provided between the upstream conveyor 1a and the downstream conveyor 1b. Therefore, the distance of the gap S in the conveying direction A of the plated metal plate corresponds to the distance between the upstream conveyor 1a and the downstream conveyor 1b in the conveying direction A. In addition, in the width direction, the gap S is the entire width between the upstream conveyor 1a and the downstream conveyor 1b.

[0046] The distance of the gap S in the conveying direction A of the plated metal sheet and the position of the gap S can be changed by moving the guide roll on the downstream side of the upstream conveyor 1a upstream or downstream and / or by moving the guide roll on the upstream side of the downstream conveyor 1b upstream or downstream. For example, to move the gap S upstream without changing the distance in the conveying direction A of the plated metal sheet, the guide roll on the downstream side of the upstream conveyor 1a can be moved upstream and the guide roll on the upstream side of the downstream conveyor 1b can be moved upstream. To move the gap S downstream without changing the distance in the conveying direction A of the plated metal sheet, the guide roll on the downstream side of the upstream conveyor 1a can be moved downstream and the guide roll on the upstream side of the downstream conveyor 1b can be moved downstream. Both the upstream conveyor 1a and the downstream conveyor 1b have tension adjustment rolls for adjusting the belt tension.

[0047] In the laser processing apparatus 100, the distance of the gap S in the conveying direction A of the plated metal sheet can be changed depending on the type and size of the plated metal, the laser processing conditions, etc. Furthermore, in the laser processing apparatus 100, the laser head 2 is moved while irradiating the plated metal sheet with laser light, so the gap S is made to follow the movement of the laser head 2 so that the gap S is positioned directly below the laser head 2. This makes it possible to prevent the belt from being damaged by the laser light. Note that this following of the gap S occurs in relation to the movement of the laser head 2 in the conveying direction A of the plated metal sheet.

[0048] The laser head 2 is positioned above the gap S. A pair of Y-axis rails 5 are provided on both sides of the conveyor 1 and extend in the conveying direction A. The reciprocating movement of the laser head 2 in the conveying direction A of the plated metal plate is guided by the Y-axis rails 5. In other words, the operating range of the laser head 2 in the conveying direction A of the plated metal plate depends on the length of the Y-axis rails 5. As described above, the gap S is made to follow the movement of the laser head 2 in the conveying direction A.

[0049] [Correction based on Rule 91 22.05.2025] On the other hand, the X-axis rail 6 extends across the entire width of the conveyor 1. The reciprocating movement of the laser head 2 in the width direction is guided by the X-axis rail 6. Note that the gap S does not follow the movement of the laser head 2 only in the conveying direction A.

[0050] That is, the laser head 2 is guided by the X-axis rail 6 and is capable of reciprocating movement, and the X-axis rail 6 is guided by the Y-axis rail 5 and is capable of reciprocating movement. Therefore, by providing the Y-axis rail 5 and the X-axis rail 6, it becomes possible to smoothly move the laser head 2 in any direction on a plane parallel to the plated metal plate, such as forward and backward, left and right, diagonal directions, and curved directions. Furthermore, even if the intended cutting location of the plated metal plate (hereinafter referred to as the "intended cutting location") has a complex shape or a smooth curve, it becomes possible to perform laser processing with high precision.

[0051] In the laser processing apparatus 100, a collection box (not shown) is provided below the gap S. The collection box follows the movement of the gap S. The collection box is provided across the entire width according to the shape of the gap S. In the laser processing apparatus 100, the plated metal plate is cut by laser light irradiated from the nozzle opening 20 of the laser head 2. Spatter generated during cutting falls and is collected in the collection box. At this time, as described above, scattering of spatter is suppressed by using the laser head 2.

[0052] (Laser Processing Method) The laser processing method according to this embodiment uses the laser processing apparatus 100 described above. Specifically, in a first step, a planned cutting location is set on the plated metal plate. Next, in a second step, a conveyance speed of the plated metal plate is set, and a movement trajectory of the laser head 2 is set accordingly to cut the planned cutting location of the plated metal plate. Next, in a third step, movement of the laser head 2 relative to the X-axis rail 6 and movement of the X-axis rail 6 relative to the Y-axis rail 5 are set so that the laser head 2 moves along the movement trajectory. These steps are then executed by computer control.

[0053] In this laser processing method, the small-diameter laser beams 22a, 22b and the large-diameter laser beams 21a, 21b are simultaneously outputted while the laser head 2 is moved along the intended cutting location of the plated metal plate. As a result, at any point in the intended cutting location, the large-diameter laser beams 21a, 21b are first irradiated, and then the small-diameter laser beams 22a, 22b are irradiated.

[0054] Therefore, in the case of a plated metal plate, the plating film is always destroyed first, and the metal plate is cut at the position where the plating film is destroyed, so that scattering of spatter can be efficiently suppressed, regardless of the direction of movement of the laser head 2. Furthermore, in the laser processing method, the small-diameter laser beams 22 a, 22 b and the large-diameter laser beams 21 a, 21 b are simply output simultaneously while the laser head 2 is moved, so that complicated control of the laser beam irradiation is not required, and laser processing can be performed relatively easily.

[0055] In the laser processing method, the relative speed of the laser head 2 to the plated metal plate is preferably 1.0 to 150 m / min. In this case, scattering of spatter can be suppressed and productivity can be improved.

[0056] Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments.

[0057] In the laser irradiation device 10 according to the first embodiment, the large-diameter laser beam 21a is a continuous ring (donut-shaped) (see (b) of FIG. 3), and in the laser irradiation device 10 according to the second embodiment, the large-diameter laser beam 21b is a round beam (see (b) of FIG. 5), but the shape is not limited to these as long as the plating film can be destroyed outside the small-diameter laser beam.

[0058] 7A to 7D are explanatory diagrams showing the shape of a large-diameter laser beam irradiated from a laser head of a laser irradiation device according to another embodiment when it reaches a plated metal plate. The large-diameter laser beam may have, for example, a circular arrangement of circles as shown in Fig. 7A, a circular arrangement of circles as shown in Fig. 7B, a spiral arrangement of circles as shown in Fig. 7C, or a concentric arrangement of multiple rings as shown in Fig. 7D.

[0059] In the laser processing apparatus 100 according to this embodiment, the conveyors 1 are arranged side by side on the left and right, but there may be only one conveyor 1, or three or more conveyors may be arranged side by side. Also, in the conveyor 1, a tension adjustment roll is used as a means for adjusting the belt tension, but this is not limited to this and any known method may be used as appropriate.

[0060] In the laser processing apparatus 100 according to this embodiment, a gap S is provided between the upstream conveyor 1a and the downstream conveyor 1b, but it is also possible to use only one of the upstream conveyor 1a or the downstream conveyor 1b, and guide the belt at the position where laser processing is performed in a downward detour away from the plated metal plate to provide a certain space.

[0061] In the laser processing apparatus 100 according to this embodiment, the laser head 2 is moved while transporting the plated metal plate, and the plated metal plate is cut with laser light irradiated from the nozzle opening 20 of the laser head 2. However, it is also possible to move the laser head 2 while the plated metal plate is stopped, for example, intermittently, and cut the plated metal plate with laser light irradiated from the nozzle opening 20 of the laser head 2.

[0062] In the laser processing apparatus 100 according to this embodiment, laser processing is performed on the plated metal plate between the conveyors 1, but this is not limiting. For example, a table with a pinholder may be provided separately from the conveyor 1, and laser processing may be performed at that location. That is, the plated metal plate may be transported by the conveyor 1, and laser processing may be performed on the plated metal plate at the table with a pinholder (processing location).

[0063] [Correction based on Rule 91 22.05.2025] In the laser processing apparatus 100 according to this embodiment, large-diameter laser beams 21a, 21b and small-diameter laser beams 22a, 22b are irradiated from a single nozzle opening 20 of the laser head 2, but the laser processing apparatus 100 may have separate nozzle openings for irradiating the large-diameter laser beams 21a, 21b and separate nozzle openings for irradiating the small-diameter laser beams 22a, 22b. Furthermore, the laser processing apparatus 100 may have separate nozzle heads for irradiating the large-diameter laser beams 21a, 21b and separate laser heads for irradiating the small-diameter laser beams 22a, 22b.

[0064] In the laser processing apparatus according to this embodiment, the X-axis rail 6 and the Y-axis rail 5 are used as means for moving the laser head 2, but the present invention is not limited to this.

[0065] The present invention can be used as a laser irradiation device 10 for irradiating a plated metal sheet with a laser beam to perform cutting (laser processing), a laser processing device 100 including the same, and a laser processing method. For example, the present invention can be used as a laser irradiation device 10 for cutting a blank material into a desired shape to obtain a processed material, or as a laser processing device 100 including the same and a laser processing method for cutting a coiled material into a blank material. The laser irradiation device 10, the laser processing device 100 including the same, and the laser processing method of the present invention can suppress the scattering of spatter when cutting even a plated metal sheet.

[0066] REFERENCE SIGNS LIST 1 conveyor 10 laser irradiation device 100 laser processing device 1a upstream conveyor 1b downstream conveyor 2 laser head 20 nozzle opening 21a, 21b large diameter laser beam 22a, 22b small diameter laser beam 3 laser oscillator 4 fiber cable 5 Y-axis rail 6 X-axis rail S gap

Claims

1. A laser irradiation device for cutting a plated metal plate, which has a plating film formed on the surface of the metal plate, with laser light, comprising: a laser head with a built-in lens for focusing laser light; and a laser oscillator for introducing laser light into the laser head; the laser light irradiated onto the plated metal plate is a round small-diameter laser beam and a large-diameter laser beam having a diameter larger than that of the small-diameter laser beam; the large-diameter laser beam destroys the plating film when irradiated, and the metal plate is cut when irradiated with the small-diameter laser beam.

2. A laser irradiation device according to claim 1, wherein the large-diameter laser beam is annular and surrounds the small-diameter laser beam, and the plating film is destroyed by irradiation of only the large-diameter laser beam, and the metal plate is cut by irradiation of only the small-diameter laser beam.

3. A laser irradiation device according to claim 1, wherein the large-diameter laser beam is round and contains the small-diameter laser beam, and the plating film is destroyed by irradiation with only the large-diameter laser beam, and the metal plate is cut by simultaneous irradiation with the small-diameter laser beam and the large-diameter laser beam.

4. [Correction based on Rule 91 22.05.2025] The laser irradiation device according to claim 1, wherein the plating film is a zinc plating film or an aluminum plating film, the metal plate is a steel plate, the thickness of the plated metal plate is 9.0 mm or less, the output of the small-diameter laser beam is 0.5 to 15.0 kW, and the output of the large-diameter laser beam is 0.1 to 10.0 kW.

5. A laser processing device for cutting a plated metal plate having a plating film formed on the surface of the metal plate with laser light, comprising: a laser irradiation device according to claim 1 for irradiating the laser light; and a conveyor for transporting the plated metal plate, wherein the laser processing device cuts the plated metal plate with the laser light while continuously transporting the plated metal plate.

6. A laser processing device according to claim 5, further comprising a pair of Y-axis rails provided on both sides of the conveyor and extending in the conveying direction, and an X-axis rail extending across the entire width of the conveyor, wherein the laser head is guided by the X-axis rail to be able to move back and forth, and the X-axis rail is guided by the Y-axis rail to be able to move back and forth.

7. A laser processing method using the laser processing device according to claim 6, wherein the small-diameter laser beam and the large-diameter laser beam are output simultaneously while the laser head is moved along the intended cutting location of the plated metal plate.

8. A laser processing method according to claim 7, wherein the relative speed of said laser head with respect to said plated metal plate is 1.0 to 150 m / min.

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