JP7146420B2 - Laser processing equipment - Google Patents

Description

The present invention relates to a laser processing apparatus.

2. Description of the Related Art There is known a technique for preventing adhesion of vaporized substances generated during laser irradiation to a transmission window (protection window) when welding is performed using a laser processing apparatus in a low-pressure atmosphere such as a vacuum.

Patent Literature 1 discloses a laser processing apparatus in which unevenness is provided on the inner peripheral surface of a beam guide positioned between a transmission window and a workpiece.

JP-A-62-107891

The technique described in Japanese Patent Application Laid-Open No. 2002-200000 prevents vaporized substances from entering the inside of the beam guide by forming unevenness on the inner peripheral surface of the beam guide and injecting a shield gas into the inside of the beam guide. The technique described in Patent Literature 1 is an effective technique at a degree of vacuum ranging from atmospheric pressure to a medium vacuum. However, in a high vacuum (10 ^-1 Pa or less) where the state of the evaporated substances is in the molecular flow region, the evaporated substances entering from the beam guide fly straight, so the effect of the unevenness provided inside the beam guide is small. Become. In addition, simply injecting the shield gas makes it difficult for the molecules of the shield gas to collide with the vaporized substances in the molecular flow, so the effect of injecting the shield gas may be reduced. Therefore, in Patent Document 1, there is a possibility that it is not possible to prevent evaporation substances from adhering to the protective window when performing welding in a high vacuum.

An object of the present invention is to solve the above-described problems, and to provide a laser processing apparatus capable of suppressing adhesion of vaporized substances entering a laser irradiation nozzle to a protective window during welding in a high vacuum. and

A laser processing apparatus according to a first aspect of the present invention includes a chamber, a laser oscillator provided outside the chamber for oscillating laser light, a laser irradiation nozzle provided inside the chamber, and a condenser lens. a laser head having a protective window; a shield gas injection device for injecting shield gas into an internal space of the laser irradiation nozzle; a conductance plate having a hole in the center with a hole diameter designed based on the inner diameter of the laser irradiation nozzle; and an exhaust device for controlling the pressure inside the chamber, wherein the conductance plate The flow of vaporized material in the internal space of the laser irradiation nozzle is controlled to be a medium flow or a viscous flow.

With this structure, the shield gas can be injected into the internal space of the laser irradiation nozzle, and the conductance plate provided in the internal space of the laser irradiation nozzle can be cooled. Therefore, when welding in a high vacuum, it is possible to suppress adhesion of vaporized substances that have entered the laser irradiation nozzle to the protective window.

Further, the conductance plate has an annular shape with a hole in the center. .3· _R ·T/√2·NA·π·σ ² ·{(Q _g /C)+P ₀ } is preferably satisfied. where, _R : gas constant, T (K): absolute temperature, NA: Avogadro's constant, σ (m): molecular diameter of shielding gas, Q _g (Pa·m ³ /s): supply rate of shielding gas , P ₀ (Pa): the pressure in the chamber.

This structure controls the flow of vaporized material in the internal space of the laser irradiation nozzle. Therefore, since the effect of the shield gas is improved, it is possible to further suppress adhesion of vaporized substances that have entered the laser irradiation nozzle to the protective window.

Also, the inner diameter D (m) of the laser irradiation nozzle preferably satisfies D>2.1·10 ⁻² /{(10/C)+100}.

With this structure, it is possible to appropriately control the flow of vaporized material in the internal space of the laser irradiation nozzle. Therefore, it is possible to further suppress adhesion of evaporated substances that have entered the laser irradiation nozzle to the protective window.

Moreover, it is preferable that a plurality of the conductance plates are provided, and the holes of the plurality of conductance plates gradually become smaller toward the downstream side.

With this structure, it is possible to physically suppress the intrusion of vaporized substances into the laser irradiation nozzle. Therefore, it is possible to further suppress adhesion of evaporated substances that have entered the laser irradiation nozzle to the protective window.

Moreover, it is preferable to provide a cooling part for cooling the conductance plate.

This structure allows the conductance plate to be cooled. Therefore, the vaporized material that has entered the inside of the laser irradiation nozzle is cooled, solidified, and adheres to the conductance plate, so that the vaporized material that has entered the laser irradiation nozzle can be further suppressed from adhering to the protective window. .

Moreover, it is preferable to provide a nozzle exhaust device provided in the laser irradiation nozzle for exhausting the shield gas injected into the internal space of the laser irradiation nozzle to the outside.

With this structure, the shielding gas that has entered the internal space of the laser irradiation nozzle can be exhausted to the outside. Therefore, since the supply amount of the shield gas can be increased, it is possible to further suppress adhesion of vaporized substances that have entered the laser irradiation nozzle to the protective window.

A laser processing apparatus according to a second aspect of the present invention includes a chamber, a laser oscillator provided outside the chamber for oscillating laser light, a laser irradiation nozzle provided inside the chamber, and a condenser lens. a laser head having a protective window for protecting the condenser lens; a shield gas injection device for injecting shield gas into an internal space of the laser irradiation nozzle; An exhaust device is provided for exhausting the shield gas injected into the space to the outside.

With this structure, the shield gas can be injected into the internal space of the laser irradiation nozzle, and the shield gas injected into the inside of the laser irradiation nozzle can be exhausted to the outside of the chamber. Therefore, when welding in a high vacuum, it is possible to suppress adhesion of vaporized substances that have entered the laser irradiation nozzle to the protective window.

Further, it is preferable that the internal space includes a conductance plate provided downstream of the protective window in the irradiation direction of the laser beam.

This structure controls the flow of vaporized material in the internal space of the laser irradiation nozzle. As a result, the effect of the shielding gas is improved, so that deposition of vaporized substances that have entered the laser irradiation nozzle onto the protective window can be further suppressed.

FIG. 1 is a diagram showing an outline of a laser processing apparatus to which each embodiment of the present invention is applied. FIG. 2 is a diagram for explaining gas flow in a laser processing apparatus to which each embodiment of the present invention is applied. FIG. 3 is a diagram showing an example of the configuration of the laser head according to the first embodiment of the invention. FIG. 4 is a table for explaining the state of vaporized substances inside the laser irradiation nozzle. FIG. 5 is a diagram showing an example of the configuration of the cooling section of the laser head according to the first embodiment of the present invention. FIG. 6 is a diagram showing an example of the configuration of a laser head according to a modification of the first embodiment of the invention. FIG. 7 is a diagram showing an example of the configuration of a laser head according to a second embodiment of the invention. FIG. 8 is a diagram showing an example of the configuration of a laser head according to the third embodiment of the invention.

A preferred embodiment of a laser processing apparatus according to the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that the present invention is not limited by this embodiment, and when there are a plurality of embodiments, a combination of each embodiment is also included.

An outline of a laser processing apparatus according to an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a schematic diagram showing an outline of a laser processing apparatus according to an embodiment of the present invention. Detailed descriptions and illustrations of components that are not directly related to the present invention are omitted.

As shown in FIG. 1, the laser processing apparatus 10 includes a chamber 11, a laser oscillator 12, a shield gas injection device 13, an exhaust device 14, a moving mechanism 15, a control device 16, an optical fiber cable 21, It includes a laser head 30 , a conductance plate 40 and a cooling section 50 . In this embodiment, the laser processing device 10 is, for example, a device for welding the workpiece T in a vacuum.

The chamber 11 is a container that creates a vacuum in its interior space. In this embodiment, the vacuum is assumed to be, for example, a high vacuum of the order of 10 ⁻¹ (Pa: Pascal) or less.

The laser oscillator 12 is provided outside the chamber 11 and oscillates a laser for irradiating the object T to be processed. A laser oscillator 12 is connected to a laser head 30 via an optical fiber cable 21 . In this case, the laser oscillated by the laser oscillator 12 is propagated to the laser head 30 via the optical fiber cable 21, and then irradiated to the workpiece T as the laser light L. As shown in FIG.

The shield gas injection device 13 is provided outside the chamber 11 and supplies shield gas to the internal space of the laser irradiation nozzle 31 of the laser head 30 through the shield gas supply pipe 22 . A pressure regulator 131 and a flow rate regulator 132 are connected to the shield gas injection device 13 . The pressure regulator 131 adjusts the pressure of the shield gas that the shield gas injection device 13 injects into the laser irradiation nozzle 31 . The flow rate adjuster 132 adjusts the flow rate of the shield gas that the shield gas injection device 13 injects into the laser irradiation nozzle 31 . In this embodiment, the shield gas is nitrogen, argon, or the like.

The evacuation device 14 is provided outside the chamber 11 and forms a vacuum inside the chamber 11 by evacuating the air inside the chamber 11 . The evacuation device 14 can be realized, for example, by a vacuum pump.

The moving mechanism 15 is provided inside the chamber 11 and moves the laser head 30 inside the chamber 11 . Although the movement mechanism 15 is not particularly limited, for example, the movement mechanism 15 moves the laser head 30 not only in three-dimensional directions but also in angular directions about the optical axis. In FIG. 1, an orthogonal coordinate system is used, in which the x direction is the left-right direction, the y direction is the front-rear direction (depth direction), and the z direction is the height direction.

The control device 16 is provided outside the chamber 11 and connected to the laser oscillator 12, the shield gas injection device 13, the pressure regulator 131, the flow rate regulator 132, the exhaust device 14, and the movement mechanism 15. there is The control device 16 controls the operation of the laser processing device 10 by controlling each device. The control device 16 adjusts the conditions of the laser light L emitted from the laser head 30 by controlling the laser oscillator 12, for example. The control device 16 controls, for example, the shield gas injection device 13, the pressure regulator 131, and the flow rate regulator 132, thereby adjusting the pressure and flow rate of the shield gas injected into the laser irradiation nozzle 31. do. The control device 16 adjusts the pressure inside the chamber 11 by controlling the exhaust device 14, for example. The control device 16 moves the laser head 30 and adjusts the irradiation position of the laser beam L on the workpiece T by controlling the moving mechanism 15, for example. Such a control device 16 can be realized by a device having an electronic circuit including a CPU (Central Processing Unit).

An optical fiber cable 21 connects a laser oscillator 12 provided outside the chamber 11 and a laser head 30 provided inside the chamber 11 . The optical fiber cable 21 propagates the laser light oscillated by the laser oscillator 12 to the laser head 30 .

The laser head 30 is provided inside the chamber 11 and has a laser irradiation nozzle 31 , a condenser lens 32 and a protection window 33 . The laser irradiation nozzle 31 has, for example, a cylindrical shape, and is a nozzle through which the laser light supplied from the laser oscillator 12 is passed. The condenser lens 32 condenses the laser supplied from the laser oscillator 12 inside the laser irradiation nozzle 31 . The protective window 33 is provided inside the laser irradiation nozzle 31 downstream of the condenser lens 32 in the irradiation direction of the laser light L, and prevents fumes and the like generated when the object T to be processed is irradiated with the laser light L. protects the condenser lens 32 from the evaporated material. As a result, the laser beam L is irradiated from the tip of the laser irradiation nozzle 31 through the protective window 33 .

The conductance plate 40 is at least one annular plate provided on the downstream side of the protection window 33 in the irradiation direction of the laser light L, although the details will be described later. The conductance plate 40 controls the flow of vaporized material in the internal space of the laser irradiation nozzle 31 so that it changes from molecular flow to intermediate flow or viscous flow.

The cooling unit 50 is provided outside the laser irradiation nozzle 31 at least in a region where the conductance plate 40 is provided, although the details will be described later. Although the cooling unit 50 is not particularly limited, it is, for example, a cooler capable of supplying a liquid coolant to the inside.

Here, the pressure inside the chamber 11 will be described with reference to FIG. FIG. 2 is a diagram showing gas flow in the internal space of the chamber 11. As shown in FIG.

In FIG. 2, it is assumed that processing is performed while the pressure inside the chamber 11 is P (Pa). At this time, if the exhaust speed of the exhaust device 14 is S (m ³ /s), the exhaust amount of the exhaust device 14 can be expressed as PS (Pa·m ³ /s). Also, the amount of gas released from the inner wall of the chamber 11 is Q _C (Pa·m ³ /s), the amount of gas generated from the workpiece T during welding is Q _W (Pa·m ³ /s), and the laser irradiation nozzle 31 Let Q _g (Pa·m ³ /s) be the amount of shielding gas supplied to , and P ₀ (Pa) be the ultimate pressure of the exhaust device 14 . In this case, each parameter satisfies the following relational expression.
Qg=PS-( _QC + _QW + _P0S ) ( ₁ )

As shown in formula (1), in order to maintain the state of the predetermined pressure P (Pa) inside the chamber 11, the supply amount Q _g (Pa·m ³ /s) of the shielding gas must satisfy the following relationship: must satisfy the formula.
Qg≦PS-( _QC + _QW + _P0S ) ( ₂ )

Specifically, the larger the supply amount Q _g (Pa·m ³ /s) of the shielding gas, the closer the flow of the vaporized material entering the laser irradiation nozzle 31 can be to an intermediate flow or a viscous flow. As a result, adhesion of evaporated substances to the protective window 33 can be prevented. However, when the supply amount Q _g (Pa·m ³ /s) of the shielding gas increases, the pressure inside the chamber 11 increases. In this embodiment, the control device 16 obtains the pressure inside the chamber 11 by means of a pressure gauge (not shown) or the like in order to control the supply amount Q _g (Pa·m ³ /s) of the shielding gas. Then, the control device 16 feeds back the obtained pressure value and controls the flow rate regulator 132 according to the equation (2), thereby controlling the supply amount Q _g (Pa·m ³ /s) of the shielding gas. . That is, the controller 16 can appropriately adjust the supply amount Q _g (Pa·m ³ /s) of the shielding gas while maintaining the pressure of the chamber 11 at vacuum.

[First embodiment]
The configuration of the laser head of the laser processing apparatus according to the first embodiment will be described in detail with reference to FIG. FIG. 3 is a diagram showing an example of the cross-sectional configuration of the laser head of the laser processing apparatus according to the first embodiment.

As shown in FIG. 3, inside the laser irradiation nozzle 31, a condenser lens 32 and a protection window 33 are provided downstream of the condenser lens 32 in the irradiation direction of the laser light L. As shown in FIG. A shield gas supply pipe 22 is connected in the vicinity of the protective window 33 to supply the shield gas. A plurality of shield gas supply pipes 22 may be provided along the contour of the laser irradiation nozzle 31 . Further, inside the laser irradiation nozzle 31, the first conductance plate 41, the second conductance plate 42, the third conductance plate 43, and the fourth conductance plate 41, the second conductance plate 42, the third conductance plate 43, and the fourth conductance plate are located downstream of the protection window 33 in the irradiation direction of the laser beam L. a plate 44; In addition, the laser irradiation nozzle 31 has at least the first conductance plate 41 to the fourth conductance plate 44, and the laser irradiation nozzle 31 in the region where the first conductance plate 41 to the fourth conductance plate 44 are provided. A cooling unit 50 is provided.

In this embodiment, the first conductance plate 41 to the fourth conductance plate 44 are annular parts provided along the inner surface of the laser irradiation nozzle 31 and having a hole diameter d (m). Also, the first conductance plate 41 to the fourth conductance plate 44 have the same shape. By providing the first to fourth conductance plates 41 to 44 inside, the state of the vaporized substance flowing in the internal space of the laser irradiation nozzle 31 can be adjusted from molecular flow to intermediate flow or viscous flow. In addition, in this embodiment, four conductance plates are provided, but this is an example and does not limit the present invention.

Here, the relationship between the inner diameter D (m) of the laser irradiation nozzle 31 and the hole diameter of each conductance plate will be described. N (N is an integer equal to or greater than 1) conductance plates are provided inside the laser irradiation nozzle 31, and when the hole diameter of the _N -th conductance plate is dN (m), the conductance of the conductance plate _CN (m ³ /s) satisfies the following relational expression.
C _N =116·(π·(d _N /2) ² )/[1−{(π·(d _N /2) ² )/(π·(D/2) ² )}] (3 )

The total conductance C (m ³ /s) of N conductance plates can be calculated by the following relational expression.
C=1/{(1/C ₁ )+(1/C ₂ )+...+(1/C _N )}...(4)

In this case, the inner diameter D(m) of the laser irradiation nozzle 31 satisfies the following relational expression.
D>2.1·10 ⁻² /{(10/C)+100} (5)

As shown in FIG. 4, the state of molecules in the internal space of the laser irradiation nozzle 31 can be determined by the Knudsen number K. As shown in FIG. The Knudsen number K is a value defined by λ/D, where λ (m) is the mean free path of a molecule and D (m) is the tube diameter of the laser irradiation nozzle 31 . When the Knudsen number is K<0.01, the evaporated substance in the internal space of the laser irradiation nozzle 31 becomes a viscous flow. When the Knudsen number is 0.01<K<0.3, the vaporized material in the internal space of the laser irradiation nozzle 31 becomes an intermediate flow. When the Knudsen number is K>0.3, the evaporated substance in the internal space of the laser irradiation nozzle 31 becomes a molecular flow. That is, based on the outer shape of the laser irradiation nozzle 31, by designing the hole diameters of the first conductance plate 41 to the fourth conductance plate 44 so that the Knudsen number becomes K<0.3, the inside of the laser irradiation nozzle 31 The state of evaporative substances in space can be controlled from molecular flow to intermediate flow or viscous flow.

Specifically, when the relationship of the following formula (6) is satisfied, the state of the vaporized substance becomes intermediate flow or viscous flow.
D=λ/K>λ/0.3 (≈3.3λ) (6)
The mean free path λ (m) in the laser irradiation nozzle 31 is defined by _R as the gas constant, T (K) as the absolute temperature, NA as the Avogadro constant, σ (m) as the molecular diameter of the shielding gas, and σ (m) as the diameter of the shield gas molecule. When the pressure in the internal space is P _g (Pa), the following relational expression is satisfied.
λ=R・T/√2・N _A・π・σ ²・P _g (7)

Here, the shielding gas supply amount is Q _g (Pa·m ³ /s), the conductance of the internal space of the laser irradiation nozzle 31 is C (m ³ /s), and the pressure inside the chamber is P ₀ (Pa). In this case, the pressure P _g (Pa) in the internal space of the laser irradiation nozzle 31 satisfies the following relational expression.
_{Pg =} ( _Qg /C)+P0 (8)

Then, R≈8.31 (JK ⁻¹ mol ⁻¹ ), T=298 (K), N _A ≈6.02·10 ²³ (mol ⁻¹ ), σ≈3.8·10 ⁻¹⁰ (m) (When the shielding gas is nitrogen), by substituting Q _g =10 (m ³ /s) and P ₀ =100 (Pa) into equations (6), (7), and (8), , equation (5) can be calculated.

Refer to FIG. 3 again. The cooling unit 50 cools the laser irradiation nozzle 31 in a region including at least the first conductance plate 41 to the fourth conductance plate 44, for example.

The cooling unit 50 will be described with reference to FIG. FIG. 5 is a schematic diagram showing an example of the configuration of the cooling unit 50. As shown in FIG. As shown in FIG. 5, the cooling part 50 is, for example, a liquid flow path wound around the outer periphery of the laser irradiation nozzle 31 and supplied with liquid coolant. Since the vaporized material is a gas, when it collides with the inner surface of the laser irradiation nozzle 31 and the first to fourth conductance plates 41 to 44, it is cooled and solidified. Therefore, the vaporized material is likely to adhere to the inner surface of the laser irradiation nozzle 31 and the first to fourth conductance plates 41 to 44 . As a result, the vaporized material is prevented from entering the upstream region of the laser irradiation nozzle 31, thereby preventing the vaporized material from adhering to the protective window. Note that the cooling unit 50 is provided over the entire laser irradiation nozzle 31 and may cool the entire laser irradiation nozzle 31 .

Next, a modified example of the conductance plate will be described with reference to FIG. FIG. 6 is a schematic diagram showing a modification of the conductance plate.

The first to fourth conductance plates 41 to 44 shown in FIG. 3 have the same shape. Here, since the laser light L is condensed by the condensing lens 32 so as to have a focal point at the position of the workpiece T, the diameter of the laser light L becomes narrower toward the tip of the laser irradiation nozzle 31 . Therefore, according to the size of the diameter of the laser beam L, the hole diameter of each of the first conductance plate 41 to the fourth conductance plate 44 can be made small.

As shown in FIG. 6, the hole diameter of the first conductance plate 41A is d ₁ (m). The hole diameter of the second conductance plate 42A is d ₂ (m). The hole diameter of the third conductance plate 43A is d ₃ (m). The hole diameter of the fourth conductance plate 44A is d ₄ (m). In this case, it is formed so that d ₄ <d ₃ <d ₂ <d ₁ . As a result, the vaporized material is physically suppressed from entering the laser irradiation nozzle 31, so that the amount of the vaporized material entering the inside of the laser irradiation nozzle 31 is reduced, and adhesion of the evaporated material to the protective window is further suppressed. be done. In this embodiment, each conductance plate has been described as an annular plate, but this is an example and does not limit the present invention. Each conductance plate may be, for example, a T-shaped plate in cross section.

As described above, in this embodiment, the pressure in the internal space of the laser irradiation nozzle 31 can be increased by providing the conductance plate in the internal space of the laser irradiation nozzle 31 . Thereby, this embodiment can suppress adhesion of evaporated substances to the protective window 33 .

In addition, in this embodiment, by cooling the conductance plate provided in the internal space of the laser irradiation nozzle 31, the vaporized material can adhere to the conductance plate. As a result, this embodiment can further suppress deposition of vaporized substances on the protection window 33 .

In addition, in this embodiment, by decreasing the hole diameter of the conductance plate toward the tip of the laser irradiation nozzle 31 , it is possible to physically suppress the intrusion of the vaporized material into the laser irradiation nozzle 31 . As a result, this embodiment can further suppress deposition of vaporized substances on the protection window 33 .

[Second embodiment]
The configuration of the laser head of the laser processing apparatus according to the second embodiment will be described in detail with reference to FIG. FIG. 7 is a diagram showing an example of a cross-sectional configuration of a laser head of a laser processing apparatus according to the second embodiment. A laser head 30A according to the second embodiment differs from the first embodiment in that a nozzle exhaust device 60 for exhausting the pressure in the internal space of the laser irradiation nozzle 31 is provided.

As shown in FIG. 7 , a nozzle exhaust device 60 is connected to the laser irradiation nozzle 31 via a nozzle exhaust pipe 61 . The nozzle exhaust device 60 may be directly attached to the laser irradiation nozzle 31 without the nozzle exhaust pipe 61 . The nozzle exhaust device 60 exhausts the injected shielding gas in the internal space of the laser irradiation nozzle 31 to the outside of the chamber 11 . Here, suppose that the exhaust amount of the nozzle exhaust device 60 is Q _n (Pa·m ³ /S). In this case, the relational expression of the supply amount Q _g (Pa·m ³ /S) of the shielding gas required to maintain the state of the predetermined pressure P inside the chamber 11 is changed as follows. .
Qg≦(PS+ _Qn )−( _QC + _{QW + P0S} ) (9)

As shown in the above equation (9), in the second embodiment, the supply amount of the shield gas can be increased by the exhaust amount of the nozzle exhaust device 60 .

As described above, in the present embodiment, by providing the nozzle exhaust device 60 in the laser irradiation nozzle 31, the supply amount of the shielding gas injected into the internal space of the laser irradiation nozzle 31 can be increased. As a result, in this embodiment, the flow of evaporative substances in the internal space of the laser irradiation nozzle 31 can be brought close to an intermediate flow or a viscous flow, so adhesion of the evaporative substances to the protective window 33 can be further prevented.

[Third embodiment]
The configuration of the laser head of the laser processing apparatus according to the third embodiment will be described in detail with reference to FIG. FIG. 8 is a diagram showing an example of a cross-sectional configuration of a laser head of a laser processing apparatus according to a third embodiment. The laser head 30B according to the third embodiment differs from the second embodiment in that the cooling section 50 is not provided and the pressure is not controlled by a conductance plate.

As shown in FIG. 8 , a nozzle exhaust device 60 is connected to the laser irradiation nozzle 31 via a nozzle exhaust pipe 61 . A first conductance plate 41 and a second conductance plate 42 are provided in the internal space of the laser irradiation nozzle 31 .

The first conductance plate 41 and the second conductance plate 42 define a space for the nozzle exhaust device 60 to exhaust gas in the laser irradiation nozzle 31 . In this case, the nozzle exhaust device 60 exhausts the shield gas in the space defined by the first conductance plate 41 and the second conductance plate 42 to the outside. That is, the supply amount of the shield gas can be increased by the exhaust amount of the nozzle exhaust device 60 . In addition, in the internal space of the laser irradiation nozzle 31, a plurality of conductance plates may be provided downstream of the protection window 33 in the irradiation direction of the laser light L.

As described above, in the present embodiment, by providing the nozzle exhaust device 60 in the laser irradiation nozzle 31, the supply amount of the shielding gas injected into the internal space of the laser irradiation nozzle 31 can be increased. As a result, in this embodiment, the flow of evaporative substances in the internal space of the laser irradiation nozzle 31 can be brought close to an intermediate flow or a viscous flow, so adhesion of the evaporative substances to the protective window 33 can be further prevented.

REFERENCE SIGNS LIST 10 laser processing device 11 chamber 12 laser oscillator 13 shield gas injection device 14 exhaust device 15 moving mechanism 16 control device 21 optical fiber cable 22 shield gas supply pipe 30 laser head 31 laser irradiation nozzle 32 condenser lens 33 protection window 40 conductance plate 41 , 41A first conductance plate 42, 42A second conductance plate 43, 43A third conductance plate 44, 44A fourth conductance plate 50 cooling unit 60 nozzle exhaust device 61 nozzle exhaust pipe L laser beam T workpiece

Claims (10)

a chamber;
a laser oscillator provided outside the chamber for oscillating laser light;
a laser head provided inside the chamber and having a laser irradiation nozzle, a condenser lens, and a protective window;
a shield gas injection device for injecting a shield gas into the internal space of the laser irradiation nozzle;
a conductance plate provided in the internal space downstream of the protective window in the irradiation direction of the laser beam , and having a hole in the center portion with a hole diameter designed based on the inner diameter of the laser irradiation nozzle ;
an exhaust device that controls the pressure inside the chamber,
The laser processing apparatus, wherein the conductance plate controls the flow of the vaporized substance in the internal space of the laser irradiation nozzle to a medium flow or a viscous flow. 2. The laser processing apparatus according to claim 1 , further comprising a cooling part for cooling said conductance plate. a chamber;
a laser oscillator provided outside the chamber for oscillating laser light;
a laser head provided inside the chamber and having a laser irradiation nozzle, a condenser lens, and a protective window;
a shield gas injection device for injecting a shield gas into the internal space of the laser irradiation nozzle;
a conductance plate provided in the internal space downstream of the protection window in the irradiation direction of the laser light;
an exhaust device for controlling the pressure inside the chamber;
a cooling unit that cools the conductance plate;
with
The laser processing apparatus, wherein the conductance plate controls the flow of the vaporized substance in the internal space of the laser irradiation nozzle to a medium flow or a viscous flow. 4. The laser processing apparatus according to any one of claims 1 to 3 , further comprising a nozzle exhaust device provided in said laser irradiation nozzle for exhausting said shielding gas injected into said internal space of said laser irradiation nozzle to the outside. . a chamber;
a laser oscillator provided outside the chamber for oscillating laser light;
a laser head provided inside the chamber and having a laser irradiation nozzle, a condenser lens, and a protective window;
a shield gas injection device for injecting a shield gas into the internal space of the laser irradiation nozzle;
a conductance plate provided in the internal space downstream of the protection window in the irradiation direction of the laser light;
an exhaust device for controlling the pressure inside the chamber;
a nozzle exhaust device provided in the laser irradiation nozzle for exhausting the shielding gas injected into the internal space of the laser irradiation nozzle to the outside;
with
The laser processing apparatus, wherein the conductance plate controls the flow of the vaporized substance in the internal space of the laser irradiation nozzle to a medium flow or a viscous flow. The conductance plate has an annular shape with a hole in the center,
When the inner diameter of the laser irradiation nozzle is D (m) and the conductance of the conductance plate is C, D>3.3 R T/√2 N _A π σ ² {(Q _g /C )+P ₀ }, the laser processing apparatus according to claim 1 . 7. The laser processing apparatus according to claim 6 , wherein said inner diameter D (m) of said laser irradiation nozzle satisfies D>2.1·10 ⁻² /{(10/C)+100}. A plurality of the conductance plates,
The laser processing apparatus according to any one of claims 1 to 7 , wherein the holes of the plurality of conductance plates gradually become smaller toward the downstream side. a chamber;
a laser oscillator provided outside the chamber for oscillating laser light;
a laser head provided inside the chamber and having a laser irradiation nozzle, a condenser lens, and a protection window for protecting the condenser lens;
a shield gas injection device for injecting a shield gas into the internal space of the laser irradiation nozzle;
A laser processing apparatus comprising an exhaust device provided in the laser irradiation nozzle for exhausting the shield gas injected into an internal space of the laser irradiation nozzle to the outside. 10. The laser processing apparatus according to claim 9 , further comprising a conductance plate provided in said internal space downstream of said protective window in the irradiation direction of said laser beam.

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