JP2023124356A - Laser processing device - Google Patents

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

The present invention relates to a laser processing apparatus that jets an assist gas to a workpiece to discharge debris and cool a processed portion.

2. Description of the Related Art Laser processing apparatuses are known for performing cutting, drilling, welding, surface marking processing, and the like on workpieces such as metals. This type of laser processing apparatus includes a laser oscillator, an optical system, a processing head, etc. A laser beam output from the laser oscillator is guided through the optical system to the processing head, and is irradiated onto a workpiece from a nozzle port. Along with this, an assist gas is jetted coaxially with the laser beam from the nozzle port of the processing head to discharge debris and cool the processed portion (see, for example, Patent Document 1).

By the way, some laser processing apparatuses for marking, grooving, etc. of a workpiece are provided with a large-area optical system of, for example, 20φ or more, which is a combination of a galvanometer scanner and an fθ lens in the optical system. In this case, since the opening diameter of the nozzle port at the tip of the processing head also becomes large, there is a situation in which the flow velocity of the assist gas cannot be increased sufficiently. For this reason, in Patent Document 1, a so-called double nozzle is adopted in which an opening for ejecting gas is separately provided around the opening from which the laser beam is output at the tip of the nozzle.

JP-A-7-223086

However, as described above, when the double nozzles are provided, the structure of the nozzles becomes complicated, and a negative pressure region is formed inside the nozzles by the assist gas jetted at high speed. Due to the formation of this negative pressure region, an ascending air current is generated from the processing point to the central part of the injection at the center of the nozzle, and there is a problem that ejected matter such as debris is caught inside the nozzle. Problems such as fouling of optical parts and attenuation of laser output occur due to the entrainment of the ejected matter. In addition, there is also the problem of non-uniformity in the flow velocity for each injection position. In addition to the main assist gas, there is also a method in which the auxiliary assist gas is injected from the side around the main assist gas. lead to a decline.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and its object is to supply a high-speed assist gas with a simple structure even in a device having a large-area optical system and a relatively large nozzle port. To provide a laser processing apparatus capable of

In order to achieve the above object, the laser processing apparatus (1) of the present invention transmits a laser beam (L) from a laser oscillator (2) through an optical system (4) to a nozzle port ( 10), and an assist gas supply mechanism (5) injects the assist gas (A) from the nozzle port coaxially with the laser beam. It has a nozzle portion (9) whose diameter is reduced toward the nozzle port, and has an airtight gas purge area (11) on the base end side that opens toward the nozzle portion side. A slit-shaped ejection port (13) is positioned to flow gas along the inner wall surface of the nozzle portion toward the nozzle port at high speed, and the assist gas supply mechanism supplies the first assist gas to the gas purge area. in a positive pressure state, and a second gas supply unit (15) for supplying a second assist gas to the ejection port.

According to the above configuration, the laser beam is emitted from the laser oscillator through the optical system and irradiated onto the workpiece from the nozzle port at the tip of the machining head. Along with this, the assist gas is injected coaxially with the laser beam from the nozzle port by the assist gas supply mechanism. At this time, the second assist gas supplied at a relatively high pressure from the second gas supply section of the assist gas supply mechanism is supplied from the slit-shaped ejection port at the base end of the nozzle section to the inner wall surface of the nozzle section. is jetted at high speed toward the nozzle port along the In addition, a first assist gas is supplied to the gas purge area at a positive pressure by a first gas supply section.

Here, when an optical system with a large area is provided, there is a circumstance that the opening diameter of the nozzle port also becomes large. becomes a negative pressure, drawing in the first assist gas in the gas purge area communicating with the inside of the nozzle. By maintaining the positive pressure of the first assist gas in the gas purge area, the first assist gas can be actively introduced into the negative pressure area. As a result, the assist gas in which the first and second assist gases are mixed is ejected coaxially with the laser beam from the nozzle port at a relatively high speed. This makes it possible to eliminate the unstable negative pressure region inside the nozzle and to perform stable injection by positively drawing in the first assist gas. As a result, the gas flow velocity inside the nozzle can be made uniform, and the problems associated with the formation of the negative pressure region can be eliminated. Therefore, even if the laser has a large-area optical system and a relatively large nozzle port, it is possible to supply a high-speed assist gas with a simple structure, thereby enabling high-quality laser processing.

The figure which shows one Embodiment and shows roughly the whole structure of a laser processing apparatus. Diagram showing the processing head Cross-sectional view schematically showing the internal configuration of the processing head

(one embodiment)
An embodiment will be described below with reference to the drawings. In this embodiment, a specific example will be described in which the surface of a work W made of a metal plate is subjected to marking processing. FIG. 1 schematically shows the overall configuration of a laser processing apparatus 1 according to this embodiment. This laser processing apparatus 1 includes a well-known laser oscillator 2 , a processing head 3 , and an optical system 4 that guides laser light output from the laser oscillator 2 to the processing head 3 . Further, an assist gas supply mechanism 5 for injecting an assist gas G to the work W is provided. Although not shown, a moving mechanism for moving the machining head 3 relative to the work W is also provided.

The optical system 4 includes a mirror 4a for bending the optical path of the laser beam L, and is positioned above the processing head 3 on the base end side and includes a galvanometer scanner 6 and an fθ lens 7 . Thus, the optical system 4 is a large-area optical system. The large-area optical system means an optical system having a lens diameter of 20 mmφ or more, for example. The galvanometer scanner 6 is controlled by a control device 8 including a computer. Further, the control device 8 is configured to control the laser processing device 1 as a whole.

Here, the processing head 3 will be described in detail with reference to FIGS. 2 and 3 as well. As shown in FIG. 2, the processing head 3 has, for example, a cylindrical body 3a, and a galvanometer scanner 6 and an f.theta. A nozzle portion 9 is provided at the lower end portion, which is the tip portion of the body 3a. A nozzle port 10 for injecting the laser beam L and the assist gas G is provided on the bottom surface of the nozzle portion 9 . In this case, the nozzle port 10 is also relatively large for scanning with the laser beam L, for example, the diameter is 8 mmφ or more.

As also shown in FIGS. 2 and 3, a gas purge area 11 is provided between the f.theta. The gas purge area 11 is open to the nozzle portion 9 side and has one or more supply ports 11a on its peripheral wall portion, so that the gas does not leak to any part other than the nozzle portion 9 side. It is airtightly configured. As shown in FIG. 1, the supply port 11a of the gas purge area 11 is connected to the first gas supply section 12, and the first assist gas is supplied from the first gas supply section 12 at positive pressure. It has become so. An inert gas such as helium gas or argon gas is used as the first assist gas.

As shown in FIG. 3, the inner wall surface of the nozzle portion 9 is configured to have a tapered shape in this case, in which the diameter of the inner wall surface of the nozzle portion 9 decreases from the upper end toward the nozzle port 10 as a whole. The upper end of the nozzle portion 9 has a circular opening so as to communicate with the gas purge area 11 . The nozzle portion 9 is provided with a slit-shaped ejection port 13 located on the base end side, i.e., near the upper portion thereof, over the entire circumference thereof for allowing the second assist gas to flow into the nozzle portion 9 at high speed. It is The ejection port 13 is provided downward along the taper of the inner wall surface of the nozzle portion 9, and communicates with, for example, two supply ports 14 provided at both the left and right ends in the figure.

At this time, as shown in FIG. 3, the nozzle portion 9 is configured by connecting two parts 9a and 9b in the axial direction, that is, in the vertical direction. A supply port 14 is configured. As shown in FIG. 1, the two supply ports 14 are connected to a second gas supply section 15, and the second assist gas is supplied from the second gas supply section 15 at a high pressure, for example, 0.1 MPa or higher. is supplied at a pressure of As the second assist gas, an inert gas such as nitrogen gas, which is different from the first assist gas, is used.

As a result, the second assist gas is supplied from the second gas supply unit 15 to the supply port 14 at high pressure, and ejected from the slit-shaped ejection port 13 downward, that is, in the direction of arrow A2 in FIG. 3 at high speed. The second assist gas flows along the inner wall surface of the nozzle portion 9 at high speed and is jetted from the nozzle port 10 toward the processing position of the workpiece W. As shown in FIG. An assist gas supply mechanism 5 is composed of the gas purge area 11, the first gas supply section 12, the ejection port 13, the second gas supply section 15, and the like. 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 controller 8.

Next, the operation of the laser processing apparatus 1 having the above configuration will be described. In the laser processing apparatus 1 , when performing the surface marking processing of the work W, the control device 8 drives the laser oscillator 2 and controls the galvanometer scanner 6 . As a result, as shown in FIG. 1, the laser beam L emitted from the laser oscillator 2 passes through the optical system 4 and is irradiated onto the work W from the nozzle port 10 of the processing head 3 to perform predetermined marking. 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 coaxially with the laser beam L from the nozzle port 10. be done.

As a result, the assist gas A is sprayed onto the processed portion of the work W, and the generated debris is discharged and the processed portion of the work W is cooled. At this time, specifically, as shown in FIG. It flows at high speed in the direction of the arrow A2 along the inner wall surface of the nozzle portion 9 from the shaped ejection port 13, and is jetted downward from the nozzle port 10 at high speed. At the same time, the gas purge area 11 in the processing head 3 is supplied with the first assist gas at a positive pressure from the first gas supply section 12 .

Here, when the large-area optical system 4 such as the galvanometer scanner 6 and the fθ lens 7 is provided, the opening diameter of the nozzle port 10 is also increased. However, as shown in FIG. 3, the second assist gas flows at high speed in the direction of the arrow A2 in the inner peripheral portion of the nozzle port 10, so that the inner portion becomes negative pressure and communicates with the inside of the nozzle portion 9. The first assist gas in the gas purge area 11 is drawn in the arrow A1 direction. By maintaining the positive pressure of the first assist gas in the gas purge area 11, the first assist gas can be positively introduced into the negative pressure area.

As a result, the assist gas A in which the first and second assist gases are mixed is ejected from the nozzle port 10 coaxially with the laser beam L at a relatively high speed, and sprayed onto the processed portion of the workpiece W at a high speed. will be available. Therefore, the ejection of debris and the cooling of the machined portion by the assist gas A are effectively performed. In this case, it is possible to eliminate the unstable negative pressure region inside the nozzle portion 9 and to perform stable injection by positively drawing in the first assist gas. As a result, the gas flow velocity inside the nozzle portion 9 can be made uniform, and problems such as entrainment of ejected matter such as debris into the inside of the nozzle portion 9 due to the formation of the negative pressure region can be eliminated.

As described above, according to the present embodiment, the processing head 3 is airtightly provided with the gas purge area 11 opening on the nozzle portion 9 side, and the first assist gas is supplied in a positive pressure state. The second assist gas is caused to flow along the inner wall surface of the nozzle portion 9 toward the nozzle port 10 at a high speed from the slit-shaped ejection port 13 provided. As a result, even when the optical system 4 has a large area and the nozzle port 10 is relatively large, it is possible to supply the assist gas A at a high speed with a simple structure, which in turn enables high-quality laser processing. It is possible to obtain an excellent effect.

In particular, in this embodiment, the two parts 9a and 9b that constitute the nozzle portion 9 are butted together to form the slit-shaped ejection port 13. As shown in FIG. As a result, the slit-shaped ejection port 13 can be easily formed, and the shape of the ejection port 13 and the size of the gap can be easily changed by exchanging the parts 9a and 9b. Also, by replacing the part 9b, the shape of the inner wall surface of the nozzle portion 9, for example, the taper angle, etc., can be easily changed. Adjustment of the slit width of the ejection port also facilitates adjustment of the flow velocity of the assist gas.

Further, in this embodiment, the first gas supply section 12 and the second gas supply section 15 are configured to be able to supply different types of assist gas. With this configuration, the first assist gas and the second assist gas can be selectively used. In this embodiment, for example, nitrogen gas, which is relatively inexpensive, is used as the second assist gas, which is used more frequently, and helium gas, which is relatively expensive but has a high cooling effect, is used as the first assist gas. adopted. As a result, high-quality processing can be performed while suppressing the cost of the assist gas as a whole.

(Other embodiments)
Although illustration is omitted, several other embodiments will be described below. In the above embodiment, different types of gases are used as the first assist gas and the second assist gas, but the same type of gas is supplied to the first gas supply section and the second gas supply section. can be configured as According to this, only one kind of assist gas can be used, and the configuration can be simplified as compared with the case where two kinds of gases are used. As the type of assist gas, various inert gases such as carbon dioxide can be employed in addition to those described above.

Also, the first assist gas cooled by an air cooler or the like can be supplied to the gas purge area, whereby the cooling effect of the processing portion can be further enhanced. If the supply port 14 for supplying the second assist gas to the ejection port 13 is configured to supply gas from the tangential direction, the second assist gas flowing from the ejection port 13 can be jetted while being spirally rotated. can be done. The shape of the nozzle port is not limited to circular, but may be other shapes such as square. It is also possible to change the flow direction and flow velocity by making the nozzle mouth part a so-called Laval shape. By enclosing, for example, a shield plate between the tip portion of the processing head and the processing surface of the workpiece, processing can be performed in a gas-purged state.

Furthermore, if a suction mechanism for sucking debris from the portion between the machining head and the machining surface of the work is added, the debris can be discharged more reliably. The workpiece W may be a material other than metal, such as plastic, and may be subjected to processing other than marking, such as cutting, drilling, and grooving. The present invention is applicable not only to those equipped with a galvanometer scanner and an fθ lens, but also to those equipped with a large-area optical system such as a large-sized lens.

In addition, the overall configuration of the laser processing apparatus described in the above embodiment is merely an example, and may involve relative movement between the processing head and the workpiece, for example, by a robot device. Various modifications are possible. Although the present disclosure has been described with reference to examples, it is understood that the present disclosure is not limited to such examples or structures. The present disclosure also includes various modifications and modifications within the equivalent range. In addition, various combinations and configurations, as well as other combinations and configurations, including single elements, more, or less, are within the scope and spirit of this disclosure.

The controller and techniques described in this disclosure may be implemented by a dedicated computer provided by configuring a processor and memory programmed to perform one or more functions embodied by the computer program. can be Alternatively, the controller and techniques described in this disclosure may be implemented by a dedicated computer provided by configuring the processor with one or more dedicated hardware logic circuits. Alternatively, the controller and techniques described in this disclosure can be implemented by a combination of a processor and memory programmed to perform one or more functions and a processor configured with one or more hardware logic circuits. It may also be implemented by one or more dedicated computers configured. The computer program may also be stored as computer-executable instructions on a computer-readable non-transitional tangible storage medium.

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, and 9 is a nozzle. , 10 is a nozzle port, 11 is a gas purge area, 12 is a first gas supply unit, 13 is an injection port, 14 is a supply port, 15 is a second gas supply unit, W is a work (workpiece), and L is a laser. Light, A indicates an assist gas.

Claims (4)

A laser beam (L) from a laser oscillator (2) is irradiated from a nozzle port (9) at the tip of a processing head (5) through an optical system (4), and an assist gas supply mechanism (5) is used to irradiate the nozzle port. A laser processing apparatus (1) that injects an assist gas (A) from a laser beam coaxially with
The processing head has a nozzle portion (9) on the tip end side, the inner wall portion of which is tapered toward the nozzle port, and an airtight gas purge area (11) on the base end side that opens toward the nozzle portion side. and a slit-shaped ejection port (13) located at the base end of the nozzle portion for flowing gas along the inner wall surface of the nozzle portion toward the nozzle port at high speed,
The assist gas supply mechanism includes a first gas supply unit (12) that supplies a first assist gas to the gas purge area in a positive pressure state, and a second gas supply unit (12) that supplies a second assist gas to the ejection port. a feeder (15); and a laser processing device. 2. The laser processing apparatus according to claim 1, wherein said ejection port is formed by abutting two of the parts constituting said nozzle portion. 3. The laser processing apparatus according to claim 1, wherein the first gas supply section and the second gas supply section are configured to be capable of supplying different types of gases. 3. The laser processing apparatus according to claim 1, wherein the first gas supply section and the second gas supply section are configured to supply the same type of gas.

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