Laser Processing Equipment

Abstract

To provide a laser processing device that comprises a large-area optical system and having a comparatively large-size nozzle port, which can supply high-speed assist gas with a simple structure.SOLUTION: A processing head 3 has, at a tip side, a nozzle part 9 whose inner wall portion reduces in diameter toward a nozzle port 10, and airtightly has, at a base end side, a gas purge area 11 opening to the nozzle part 9 side, and comprises a slit-like jetting port 13, positioned at a base end portion of the nozzle part 9, through which gas is flown at a high speed along an inner wall surface of the nozzle part 9 toward the nozzle port 10. An assist gas supply mechanism 5 includes a first gas supply part 12 that supplies first assist gas in a positive pressure state to the gas purge area 11 and a second gas supply part 15 that supplies second assist gas to the jetting port 13.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a laser processing apparatus that ejects debris and cools a processing area by injecting an assist gas onto a workpiece. [Background technology]

[0002] For example, there is known a laser processing device for cutting, drilling, welding, surface marking, etc., of a workpiece such as a metal. This type of laser processing device includes a laser oscillator, an optical system, a processing head, etc., and guides a laser beam output from the laser oscillator to the processing head via the optical system, and irradiates the workpiece from a nozzle opening. In addition, it is configured to inject an assist gas from the nozzle opening of the processing head coaxially with the laser beam, to discharge debris and cool the processed part (see, for example, Patent Document 1).

[0003] Incidentally, for example, in laser processing devices that perform marking or groove processing on workpieces, some are equipped with a large-area optical system, for example, 20φ or more, in which a galvanometer scanner and an fθ lens are combined in the optical system. In this case, the opening diameter of the nozzle port at the tip of the processing head is also large, so that the flow rate of the assist gas cannot be made sufficiently high. For this reason, in Patent Document 1, a so-called double nozzle is adopted at the tip of the nozzle, in which a separate port for gas ejection is provided around the port from which the laser light is output. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 7-223086 Summary of the Invention [Problem to be solved by the invention]

[0005] However, as described above, in the case of providing a double nozzle, the nozzle configuration becomes complicated, and a negative pressure region is formed inside the nozzle by the assist gas ejected at high speed. The formation of this negative pressure region generates an updraft from the processing point to the center of the nozzle, which causes problems with debris and other ejected material being drawn into the nozzle. This ejection of material causes problems such as damage to optical components and attenuation of laser output. There is also a problem of uneven flow speed at each ejection position. In addition to the main assist gas, there is also a type of gas injection system that ejects auxiliary assist gas from the side around the main assist gas, but this leads to a decrease in processing quality compared to the case of ejecting assist gas at high speed coaxially with the laser light.

[0006] The present invention has been made in consideration of the above circumstances, and its object is to provide a laser processing apparatus that is capable of supplying assist gas at high speed with a simple configuration, even when it is equipped with a large-area optical system and has a relatively large nozzle orifice. [Means for solving the problem]

[0007] In order to achieve the above object, the laser processing apparatus (1) of the present invention irradiates laser light (L) from a laser oscillator (2) through an optical system (4) from a nozzle opening (10) at the tip of a processing head (3), and injects an assist gas (A) from the nozzle opening coaxially with the laser light by an assist gas supply mechanism (5). The processing head has a nozzle section (9) at its tip side whose inner wall section narrows toward the nozzle opening, and has an airtight gas purge area (11) at its base end side that opens toward the nozzle section, and is equipped with a slit-shaped nozzle (13) located at the base end of the nozzle section and that flows gas at high speed along the inner wall surface of the nozzle section toward the nozzle opening. The assist gas supply mechanism includes a first gas supply section (12) that supplies a first assist gas to the gas purge area under positive pressure, and a second gas supply section (15) that supplies a second assist gas to the nozzle opening.

[0008] According to the above configuration, the laser beam is irradiated from the laser oscillator through the optical system to the workpiece through the nozzle opening at the tip of the processing head. At the same time, the assist gas supply mechanism ejects the assist gas from the nozzle opening coaxially with the laser beam. At this time, the second assist gas supplied at a relatively high pressure by the second gas supply unit of the assist gas supply mechanism is ejected at high speed from the slit-shaped ejection port at the base end of the nozzle unit along the inner wall surface of the nozzle unit toward the nozzle opening. In addition, the first assist gas is supplied at positive pressure to the gas purge area by the first gas supply unit.

[0009] Here, when a large-area optical system is provided, the opening diameter of the nozzle port is large. However, the second assist gas flows at high speed through the inner part of the nozzle port near the outer periphery, causing the inner part to become negative pressure, and drawing in the first assist gas in the gas purge area that is connected to the nozzle part. By maintaining the first assist gas in the gas purge area at positive pressure, the first assist gas can be actively introduced into the negative pressure area. As a result, the assist gas in a state in which the first and second assist gases are mixed is ejected from the nozzle port at a relatively high speed coaxially with the laser light. This allows stable ejection by actively drawing in the first assist gas while eliminating the unstable negative pressure area inside the nozzle. As a result, the gas flow rate inside the nozzle is made uniform, and the above-mentioned problems associated with the formation of the negative pressure area can be eliminated. Therefore, even when a large-area optical system is provided and the nozzle port is relatively large, it is possible to supply the assist gas at a high speed with a simple configuration, and thus high-quality laser processing is possible. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram showing an embodiment of a laser processing apparatus. [Diagram 2] Diagram showing the processing head part [Diagram 3] FIG. 3 is a cross-sectional view showing an internal configuration of the processing head; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] (One embodiment) An embodiment will be described below with reference to the drawings. In this embodiment, a specific example will be described in which a surface marking process is performed on a workpiece W made of, for example, a metal plate. FIG. 1 shows a schematic overall configuration of a laser processing device 1 according to this embodiment. This laser processing device 1 includes a known laser oscillator 2, a processing head 3, and an optical system 4 that guides a laser beam output from the laser oscillator 2 to the processing head 3. In addition, the laser processing device 1 includes an assist gas supply mechanism 5 that injects an assist gas G onto the workpiece W. Although not shown, a movement mechanism for moving the processing head 3 relative to the workpiece W is also provided.

[0012] The optical system 4 includes a mirror 4a for bending the optical path of the laser light L, and is also provided with a galvanometer scanner 6 and an fθ lens 7 located at the upper part, which is the base end side, of the processing head 3. This makes the optical system 4 a large-area optical system. Note that a large-area optical system refers to an optical system in which the lens diameter is, for example, 20 mmφ or more. The galvanometer scanner 6 is controlled by a control device 8 including a computer. The control device 8 is also configured to control the entire laser processing apparatus 1.

[0013] Here, the processing head 3 will be described in detail with reference to Figs. 2 and 3. As shown in Fig. 2, the processing head 3 has, for example, a cylindrical body 3a, and the galvanometer scanner 6 and the fθ lens 7 constituting the optical system 4 described above are assembled in the upper part of the body 3a. A nozzle section 9 is provided at the lower end, which is the tip part of the body 3a. A nozzle opening 10 for spraying the laser light L and the assist gas G is provided at the bottom part of the nozzle section 9. In this case, the nozzle opening 10 is also configured to be relatively large for scanning the laser light L, for example, with a diameter of 8 mmφ or more.

[0014] 2 and 3, a gas purge area 11 is provided between the fθ lens 7 and the nozzle portion 9 in the body 3. This gas purge area 11 opens to the nozzle portion 9 side and has one or more supply ports 11a in its peripheral wall, and is configured to be airtight so that gas does not leak to any side other than the nozzle portion 9 side. As shown in FIG. 1, the supply port 11a of this gas purge area 11 is connected to a first gas supply unit 12, and a first assist gas is supplied from the first gas supply unit 12 at positive pressure. As the first assist gas, for example, an inert gas such as helium gas or argon gas is used.

[0015] 3, the nozzle portion 9 has an inner wall surface that is tapered from the upper end toward the nozzle port 10 in the figure. The upper end of the nozzle portion 9 opens in a circular shape so as to communicate with the gas purge area 11. The nozzle portion 9 is provided with a slit-shaped outlet 13 around the entire circumference at the base end side, i.e., near the upper portion, for flowing the second assist gas at high speed into the nozzle portion 9. The outlet 13 is provided facing downward along the taper of the inner wall surface of the nozzle portion 9, and communicates with supply ports 14 provided at two locations, for example, on the left and right ends in the figure.

[0016] At this time, as shown in Fig. 3, the nozzle portion 9 is formed by butting two parts 9a, 9b together in the axial direction, i.e., in the vertical direction, and the ejection port 13 and the supply port 14 are formed at the butted portion. As shown in Fig. 1, the two supply ports 14 are connected to a second gas supply unit 15, and a second assist gas is supplied from the second gas supply unit 15 at a high pressure, for example, a pressure of 0.1 MPa or more. As the second assist gas, an inert gas of a different kind from the first assist gas, for example, nitrogen gas, is used.

[0017] As a result, the second assist gas is supplied at high pressure from the second gas supply unit 15 to the supply port 14 and is ejected from the slit-shaped nozzle 13 downward, i.e., in the direction of arrow A2 in FIG. 3, at high speed. The second assist gas flows at high speed along the inner wall surface of the nozzle unit 9 and is ejected from the nozzle port 10 toward the processing position of the workpiece W. The gas purge area 11, the first gas supply unit 12, the nozzle 13, the second gas supply unit 15, etc. constitute an assist gas supply mechanism 5. Although not shown in detail, the laser oscillator 2, the first gas supply unit 12, and the second gas supply unit 15 are also controlled by the control device 8.

[0018] Next, the operation of the laser processing apparatus 1 configured as above will be described. When performing surface marking processing on the workpiece W in the laser processing apparatus 1, the control device 8 drives the laser oscillator 2 and controls the galvano scanner 6. As a result, as shown in Fig. 1, the laser light L output from the laser oscillator 2 is irradiated onto the workpiece W from the nozzle opening 10 of the processing head 3 through the optical system 4, and a predetermined marking is performed. At the same time, the control device 8 drives and controls the first gas supply unit 12 and the second gas supply unit 15, and the assist gas supply mechanism 5 injects the assist gas A from the nozzle opening 10 coaxially with the laser light L.

[0019] As a result, the assist gas A is sprayed onto the processed portion of the workpiece W, discharging generated debris and cooling the processed portion of the workpiece W. Specifically, as shown in Fig. 3, the second assist gas supplied at a relatively high pressure to the supply port 14 of the processing head 3 by the second gas supply unit 15 flows at high speed from the slit-shaped outlet 13 of the nozzle unit 9 along the inner wall surface of the nozzle unit 9 in the direction of the arrow A2, and is sprayed downward at high speed from the nozzle port 10. At the same time, the first assist gas is supplied at positive pressure from the first gas supply unit 12 to the gas purge area 11 in the processing head 3.

[0020] Here, when a large-area optical system 4 such as the galvano scanner 6 and the fθ lens 7 is provided, the opening diameter of the nozzle orifice 10 also becomes large. However, as shown in Fig. 3, the second assist gas flows at high speed in the inner peripheral portion of the nozzle orifice 10 in the direction of the arrow A2, causing the inner portion to become negative pressure, and the first assist gas in the gas purge area 11 communicating with the nozzle portion 9 is drawn in the direction of the arrow A1. Since the first assist gas in the gas purge area 11 is maintained at positive pressure, the first assist gas can be actively introduced into the negative pressure region.

[0021] As a result, the assist gas A, which is a mixture of the first and second assist gases, is ejected from the nozzle opening 10 at a relatively high speed coaxially with the laser light L, and is sprayed at high speed onto the processed portion of the workpiece W. Therefore, the assist gas A effectively removes debris and cools the processed portion. In this case, the first assist gas is actively drawn in for stable ejection while eliminating the unstable negative pressure region inside the nozzle portion 9. As a result, the gas flow speed inside the nozzle portion 9 is made uniform, and problems such as the entrainment of ejected material such as debris into the nozzle portion 9 due to the formation of a negative pressure region can be eliminated.

[0022] Thus, according to this embodiment, the processing head 3 is provided with an airtight gas purge area 11 opening on the nozzle portion 9 side, and the first assist gas is supplied under positive pressure, while the second assist gas is caused to flow at high speed from a slit-shaped nozzle 13 provided in the nozzle portion 9 along the inner wall surface of the nozzle portion 9 toward the nozzle opening 10. This makes it possible to supply the assist gas A at high speed with a simple configuration even in a case where the nozzle opening 10 is relatively large and the optical system 4 has a large area. This provides the excellent effect of enabling high-quality laser processing.

[0023] Particularly in this embodiment, the nozzle portion 9 is configured such that the two parts 9a and 9b are butted together to form the slit-shaped outlet 13. This allows the slit-shaped outlet 13 to be easily formed, and the shape and gap dimensions of the outlet 13 can be easily changed by replacing the parts 9a and 9b. In addition, the shape of the inner wall surface of the nozzle portion 9, such as the taper angle, can be easily changed by replacing the part 9b. The flow rate of the assist gas can also be easily adjusted by adjusting the slit width of the outlet.

[0024] In this embodiment, the first gas supply unit 12 and the second gas supply unit 15 are configured to be able to supply different types of assist gas. This configuration allows the first assist gas and the second assist gas to be used separately. In this embodiment, for example, a relatively inexpensive nitrogen gas is used as the second assist gas, which is used more frequently, and a relatively expensive helium gas, which has a high cooling effect, is used as the first assist gas. This makes it possible to perform high-quality processing while suppressing the overall cost of the assist gas.

[0025] (Other embodiments) Hereinafter, although illustrations are omitted, some other embodiments will be described. In the above embodiment, the first assist gas and the second assist gas are different types of gas, but the first gas supply unit and the second gas supply unit can be configured to supply the same type of gas. In this way, only one type of assist gas is required, and the configuration can be simplified compared to the case where two types of gas are used. As the type of assist gas, various inert gases such as carbon dioxide can be adopted in addition to those mentioned above.

[0026] Also, the first assist gas cooled by an air cooler or the like can be supplied to the gas purge area, which can further enhance the cooling effect of the processing part. If the supply port 14 that supplies the second assist gas to the nozzle 13 is configured to supply gas from a tangential direction, the second assist gas flowing from the nozzle 13 can be sprayed while rotating in a spiral shape. The shape of the nozzle port is not limited to a circle, and can be other shapes, such as a square. The nozzle port part can be a so-called Laval shape to change the flow direction and flow speed. By surrounding the space between the tip of the processing head and the processing surface of the workpiece with, for example, a shielding plate, processing can be performed in a gas purged state.

[0027] Furthermore, if a suction mechanism is added to suck up debris from between the processing head and the processing surface of the workpiece, it becomes possible to more reliably discharge the debris. The workpiece W may be made of plastic or other materials other than metal, and may be processed by cutting, drilling, grooving, or other methods other than marking. The present invention is not limited to those equipped with a galvanometer scanner and an fθ lens, but may be generally applied to those equipped with a large-area optical system such as a large lens.

[0028] In addition, the overall configuration of the laser processing device described in the above embodiment is merely an example, and various modifications are possible, such as a configuration involving relative movement between the processing head and the workpiece by a robot device. Although the present disclosure has been described based on the embodiment, it is understood that the present disclosure is not limited to the embodiment or structure. The present disclosure also includes various modifications and modifications within the equivalent range. In addition, various combinations and forms, and even other combinations and forms including only one element, more than one element, or less than one element, are also within the scope and concept of the present disclosure.

[0029] The control unit and the method described in the present disclosure may be realized by a special-purpose computer provided by configuring a processor and a memory programmed to execute one or more functions embodied in a computer program. Alternatively, the control unit and the method described in the present disclosure may be realized by a special-purpose computer provided by configuring a processor with one or more dedicated hardware logic circuits. Alternatively, the control unit and the method described in the present disclosure may be realized by one or more special-purpose computers configured by a combination of a processor and a memory programmed to execute one or more functions and a processor configured with one or more hardware logic circuits. Also, the computer program may be stored in a computer-readable non-transitory tangible recording medium as instructions executed by a computer. [Explanation of symbols]

[0030] In the drawings, 1 is a laser processing device, 2 is a laser oscillator, 3 is a processing head, 4 is an optical system, 5 is an assist gas supply mechanism, 6 is a galvanometer scanner, 7 is an fθ lens, 8 is a control device, 9 is a nozzle section, 10 is a nozzle port, 11 is a gas purge area, 12 is a first gas supply section, 13 is an injection port, 14 is a supply port, 15 is a second gas supply section, W is a workpiece (processed object), L is a laser light, and A is an assist gas.

Claims

1. A laser processing device (1) in which a laser beam (L) from a laser oscillator (2) is irradiated from a nozzle opening (10) at the tip of a processing head (3) through an optical system (4), and an assist gas (A) is sprayed from the nozzle opening coaxially with the laser beam by an assist gas supply mechanism (5), The processing head has a nozzle portion (9) at a tip end side, the inner wall portion of which narrows toward the nozzle opening, and has an airtight gas purge area (11) at a base end side which opens toward the nozzle portion, and is provided with a slit-shaped nozzle (13) located at the base end of the nozzle portion for flowing gas at high speed along the inner wall surface of the nozzle portion toward the nozzle opening, the assist gas supply mechanism includes a first gas supply unit (12) that supplies a first assist gas under a positive pressure to the gas purge area, and a second gas supply unit (15) that supplies a second assist gas to the nozzle; The assist gas injected from the nozzle opening is composed of a mixture of the first assist gas and the second assist gas. Laser processing equipment.

2. 2. The laser processing device according to claim 1, wherein the ejection port is formed by butting together two of the components that constitute the nozzle portion.

3. 3. The laser processing apparatus according to claim 1, wherein the first gas supply unit and the second gas supply unit are configured to be capable of supplying different types of gases.

4. 3. The laser processing apparatus according to claim 1, wherein the first gas supply unit and the second gas supply unit are configured to supply the same type of gas.

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