WO2015125522A1

WO2015125522A1 - Laser welding head, laser welding device, and gas nozzle for laser welding head

Info

Publication number: WO2015125522A1
Application number: PCT/JP2015/050952
Authority: WO
Inventors: 正人高津
Original assignee: 株式会社アマダホールディングス
Priority date: 2014-02-24
Filing date: 2015-01-15
Publication date: 2015-08-27
Also published as: JP2015157297A

Abstract

A laser welding head equipped with: a hollow head main body on the tip end of which an emission aperture that emits laser light is formed, and which is optically connected to a laser oscillator; a protective glass which covers the emission aperture and is provided on the head main body in a detachable manner; and an annular gas nozzle provided closer to the workpiece than the protective glass. A gas passage capable of being connected to a gas supply source is formed in the interior of the gas nozzle. A first nozzle, which emits gas toward the light axis of the laser light on the irradiation-direction side of the laser light, and second nozzles, which emit gas along the irradiation direction of the laser light, are formed on the gas nozzle. The first nozzle is formed so as to communicate with the gas passage and to surround the light axis of the laser light. The second nozzles are formed so as to communicate with the gas passage and to surround the first nozzle, at a position on the outside of the first nozzle in the radial direction. By means of this laser welding head it is possible to prevent fumes from interfering with the laser light and to reduce the adhesion of sputter on the protective glass.

Description

Laser welding head, laser welding apparatus, and gas nozzle for laser welding head

The present invention relates to a laser welding device for a workpiece such as a three-dimensional workpiece, a laser welding head used in the laser welding device, and a gas nozzle for the laser welding head.

Generally, a laser welding head (hereinafter simply referred to as a welding head) in a remote laser processing apparatus such as a welding robot has a hollow head body. Further, the head main body has an emission opening for emitting laser light on the tip side thereof, and is optically connected to a laser oscillator that oscillates the laser light. A galvano scanner is provided in the head body. The galvano scanner deflects and scans laser light oscillated from a laser oscillator in two orthogonal directions (a first scanning direction and a second scanning direction) and emits the laser light from an emission opening of the head body. Further, a protective glass covering the emission opening of the head body is detachably provided at the tip of the head body.

The opening area of the exit opening of the welding head is set according to the range of deflection scanning of the laser beam by the galvano scanner. Therefore, the area of the protective glass is large, and the spatter is likely to adhere to the protective glass. Further, compared to spot welding, the distance (work distance) between the welding head and the welded portion of the three-dimensional workpiece is long, and fume is likely to stay between the welding head and the three-dimensional workpiece. In order to suppress the adhesion of spatter to the protective glass and the retention of fume between the welding head and the three-dimensional workpiece, the following techniques have been developed.

The following Patent Document 1 discloses a welding head 101 according to a first prior art example as shown in FIG. The welding head 101 has a head body 103. On the side of the three-dimensional workpiece W of the protective glass 105 of the head main body 103, air A is ejected in a curtain shape so as to cover the surface of the protective glass 105, thereby forming an air curtain. The head main body 103 is provided with an air nozzle 107 for forming an air curtain. Further, an air nozzle 109 that ejects air B toward the welded portion Wa of the three-dimensional workpiece W is also provided in the vicinity of the air nozzle 107.

Patent Documents

2 and 3 below disclose a welding head 111 according to a second prior art example as shown in FIG. The welding head 111 has a head body 113. An annular air nozzle 117 that ejects air A toward the irradiation direction side of the laser beam LB is provided on the three-dimensional workpiece W side of the protective glass 115 of the head body 113. The air nozzle 117 has an air passage 119 that can be connected to an air supply source (not shown). The air nozzle 117 is formed with an annular nozzle slit 121 for ejecting air A toward the optical axis of the laser beam LB on the irradiation direction side of the laser beam LB. The nozzle slit 121 communicates with the air passage 119.

Japanese Unexamined Patent Publication No. 2006-142383 Japanese Unexamined Patent Publication No. 2012-76111 International Publication 2008/037310 Pamphlet

However, when the three-dimensional workpiece W having a complicated shape is laser-welded using the welding head 101 in the first prior art example, the three-dimensional workpiece W is ejected from the air nozzle 109 toward the welding portion Wa of the three-dimensional workpiece W. It may not reach the welding point Wa of the workpiece W. In this case, fume retention between the welding head 101 and the three-dimensional workpiece W cannot be suppressed. Here, even if an external blower (not shown) is used, fume retention between the welding head 101 and the three-dimensional workpiece W cannot be sufficiently suppressed. Therefore, the welding conditions (processing conditions) change due to the interference of the fumes with the laser beam LB, and laser welding cannot be performed stably (first problem).

Further, as shown in FIG. 5B, when laser welding is performed on the three-dimensional workpiece W from the side, the sputter S may scatter to the welding head 101 while drawing a parabola from the welding spot Wa. In this case, even if the air curtain is formed by the air nozzle 107, the adhesion of the sputter S to the protective glass 105 cannot be suppressed. For this reason, the adhesion amount of the sputter | spatter S to the protective glass 105 increases, and the replacement frequency of the protective glass 105 will increase (2nd problem).

On the other hand, when the three-dimensional workpiece W is laser-welded using the welding head 111 in the second prior art example, the air A ejected from the nozzle slit 121 merges on the optical axis of the laser beam LB, and the three-dimensional workpiece W Head toward the welding spot Wa. For this reason, even if the solid workpiece W has a complicated shape, fume retention between the welding head 111 and the solid workpiece W can be sufficiently suppressed. For this reason, there is no interference of the fumes with the laser beam LB, and laser welding can be performed stably (avoidance of the first problem).

However, as shown in FIG. 6B, when laser welding is performed on the three-dimensional workpiece W from the side, spatter S that scatters to the welding head 111 while drawing a parabola from the welding spot Wa is ejected from the nozzle slit 121. It is not possible to deflect the welding head 111 from the welded air A, and adhesion of the sputter S to the protective glass 115 cannot be suppressed. For this reason, the adhesion amount of the sputter | spatter S to the protective glass 115 increases, and the replacement frequency of the protective glass 115 will increase (2nd problem).

An object of the present invention is to provide a welding head, a laser welding apparatus, and a gas nozzle for a welding head that can solve not only the first problem but also the second problem. The present invention can be applied not only to a welding head or a laser welding apparatus provided with a galvano scanner, but also to various welding heads and laser welding apparatuses that cover the emission opening of the head body with a protective glass.

A first feature of the present invention is a laser welding head that is used in a laser welding apparatus that performs laser welding on a workpiece, and irradiates a laser beam toward a welding portion of the workpiece (including a three-dimensional workpiece). A hollow head body that is optically connected to a laser oscillator, the exit opening that emits light is formed at the tip, a protective glass that is detachably provided on the head body and covers the exit opening, and An annular gas nozzle provided on the workpiece side from the protective glass, and a gas passage that can be connected to a gas supply source is formed inside the gas nozzle, and the irradiation direction of the laser light on the gas nozzle A first nozzle that ejects gas toward the optical axis of the laser beam on the side, and a second nozzle that ejects gas along the irradiation direction of the laser beam are formed. The second nozzle communicates with the gas passage and is in a radial direction (of the gas nozzle) than the first nozzle. The second nozzle communicates with the gas passage. A laser welding head is provided at an outer position so as to surround the first nozzle.

In addition, in the specification and claims of the present application, “provided” includes not only the case of being provided directly but also the case of being provided indirectly via an interposed member. The “gas” includes an inert gas such as air or nitrogen. Further, regarding the “gas nozzle”, one gas nozzle may be provided, or a gas nozzle that is divided into a first gas nozzle in which the first nozzle is formed and a second gas nozzle in which the second nozzle is formed is provided. May be.

According to the first feature, even if the shape of the workpiece is complicated, the retention of fume between the welding head and the workpiece can be sufficiently suppressed, so that the interference of the fume with the laser beam is eliminated and stable. The workpiece can be stably laser-welded under the welding conditions (processing conditions). Moreover, even if the spatter is scattered from the welding location to the welding head, the spatter can be deflected from the welding head, so that the adhesion of the spatter to the protective glass can be reduced. As a result, the replacement frequency of the protective glass can be greatly reduced.

Here, the first nozzle is an annular first nozzle slit, a plurality of first nozzle holes formed at intervals in the circumferential direction, or a plurality of arcuate shapes formed at intervals in the circumferential direction. A plurality of second nozzle holes, annular second nozzle slits, or a plurality of circumferentially spaced second nozzle holes, each being a first nozzle slit. The arc-shaped second nozzle slit is preferable.

A second feature of the present invention is a laser welding apparatus, wherein the laser welding head of the first feature and the laser welding head are attached, and the laser welding head is approached from a side from a side, or And a moving device for moving the laser welding head so as to move the laser welding head laterally away from the workpiece.

According to a third aspect of the present invention, there is provided a gas nozzle for a laser welding head, the gas passage being formed therein and connectable to a gas supply source, and directed toward the optical axis of the laser beam on the laser beam irradiation direction side. A first nozzle that ejects gas and a second nozzle that ejects gas along the irradiation direction of the laser beam, the first nozzle being in communication with the gas passage, and the laser Formed so as to surround the optical axis of light, and the second nozzle communicates with the gas passage and is formed so as to surround the first nozzle at a position radially outward from the first nozzle. Provide a gas nozzle.

It is a schematic block diagram of the laser welding machine (welding robot) which concerns on embodiment. (A) is sectional drawing of the air nozzle (gas nozzle) of the welding head of the said laser welding machine, (b) is a bottom view of the air nozzle seen along the arrow IIB in (a). It is a side view which shows the said laser welding machine which performs laser welding from a side. It is a graph which shows the relationship between the number of processes at the time of performing laser welding from the side, and the number of spatters. (A) is a side view of the welding head which concerns on a 1st prior art example, (b) is a side view which shows this welding head which performs laser welding from a side. (A) is a side view of the welding head which concerns on a 2nd prior art example, (b) is a side view which shows this welding head which performs laser welding from a side.

Embodiments will be described with reference to FIGS. 1 to 4. As shown in FIG. 1, the remote laser welding apparatus according to the present embodiment is a welding robot 1 that performs laser welding on a three-dimensional workpiece W supported on a table (not shown). The welding robot 1 is a known 6-axis articulated robot. Further, the welding robot 1 has a robot arm (moving device) 3 at its tip. The robot arm 3 is attached with a laser welding head 5 (hereinafter simply referred to as a welding head 5) that irradiates a laser beam LB toward the welding spot Wa of the three-dimensional workpiece W. The three-dimensional workpiece W is formed by three-dimensionally connecting a plurality of metal workpieces. The welding location Wa becomes a butt portion of the metal workpiece. The robot arm 3 can move so as to approach the solid work W from the side and to move away from the solid work W to the side.

The welding head 5 includes a hollow head body 7. The head main body 7 has an emission opening 9 for emitting the laser beam LB at the tip thereof. A connector 11 is provided at the base end of the head body 7. One end of a transmission fiber 13 is connected to the connector 11. The other end of the transmission fiber 13 is optically connected to a fiber laser oscillator 15 that oscillates the laser beam LB. That is, the head body 7 is optically connected to the fiber laser oscillator 15 via the connector 11 and the transmission fiber 13.

In the head body 7, a collimating lens 17 is provided that can move along the optical axis direction of the laser beam LB. The collimating lens 17 converts the laser light LB emitted from the transmission fiber 13 into parallel light. That is, the collimating lens 17 converts the laser light LB oscillated from the fiber laser oscillator 15 into parallel light.

A galvano scanner 21 is provided on the light exit side of the collimating lens 17. The galvano scanner 21 scans while deflecting the laser beam LB emitted from the collimating lens 17 and emits the laser beam LB to the emission opening 9. The galvano scanner 21 includes a first galvanometer mirror 25 and a second galvanometer mirror 29. The first galvanometer mirror 25 is rotated by the first galvanometer motor 23 and scans while deflecting the laser beam LB in the first scanning direction. The second galvanometer mirror 29 is rotated by the second galvanometer motor 27 and scans while deflecting the laser beam LB in the second scanning direction. A reflecting mirror 31 is provided between the collimating lens 17 and the first galvanometer mirror 25.

An Fθ lens 33 is provided between the exit opening 9 and the galvano scanner 21. The Fθ lens 33 condenses the laser beam LB that is two-dimensionally scanned by the galvano scanner 21. Further, a protective glass 35 covering the emission opening 9 is detachably attached to the tip of the head body 7. Further, an annular air nozzle (gas nozzle) 37 that ejects air toward the irradiation direction side of the laser beam LB is provided on the side of the three-dimensional workpiece W with respect to the protective glass 35. The air nozzle 37 is attached to the head body 7 by a bracket 39.

As shown in FIG. 1, FIG. 2A and FIG. 2B, the air nozzle 37 has an annular first nozzle member 41 and an annular second nozzle member 43 attached with a mounting screw (not shown) or the like. They are integrally joined. An annular air passage (gas passage) 45 is formed inside the air nozzle 37. The air passage 45 can be connected to an air supply source (gas supply source) 47 such as a fan via a pipe 49. In the present embodiment, the air nozzle 37 is formed by integrally joining two annular members (the first nozzle member 41 and the second nozzle member 43), but may be configured by a single member.

Between the vicinity of the inner periphery of the first nozzle member 41 and the inner periphery of the second nozzle member 43, an annular first nozzle slit 51 (an example of a first nozzle) is an optical axis of the laser beam LB (air nozzle central axis). Is formed so as to surround. Air A is ejected from the first nozzle slit 51 toward the optical axis (air nozzle central axis) of the laser beam LB on the irradiation direction side of the laser beam LB. That is, an annular first nozzle slit 51 is formed on the inner periphery of the air nozzle 37 so as to surround the optical axis of the laser beam LB. In other words, the gas ejection direction of the first nozzle slit 51 is directed to the optical axis of the laser beam LB on the irradiation direction side of the laser beam LB. Further, the first nozzle slit 51 is communicated with the air passage 45. In addition, an annular shim (not shown) surrounding the air passage 45 is interposed between the first nozzle member 41 and the second nozzle member 43 to adjust the size of the first nozzle slit 51. Also good. The first nozzle includes a plurality of first nozzle holes (not shown) formed at intervals in the circumferential direction, and a plurality of arc-shaped first nozzle slits formed at intervals in the circumferential direction ( (Not shown) may be formed (another example of the first nozzle).

In the vicinity of the inner peripheral edge of the second nozzle member 43, a plurality of second nozzle holes 53 (an example of second nozzles) are formed so as to surround the first nozzle slit 51. The air B is ejected from the second nozzle hole 53 along the irradiation direction of the laser beam LB (air nozzle central axis). That is, a plurality of second nozzle holes 53 are formed at intervals in the circumferential direction so as to surround the optical axis of the laser beam LB at a position radially outside the first nozzle slit 51 of the air nozzle 37. In other words, the gas ejection direction of the second nozzle hole 53 is set parallel to the irradiation direction of the laser beam LB. Further, the plurality of second nozzle holes 53 communicate with the air passage 45. The second nozzle may be formed as an annular second nozzle slit (not shown) or a plurality of arcuate second nozzle slits (not shown) formed at intervals in the circumferential direction. (Another example of the second nozzle). The second nozzle may be formed on another annular air nozzle (not shown) having a diameter larger than the diameter of the air nozzle 37.

According to the welding robot 1 having the above-described configuration, the welding head 5 is moved to a position corresponding to the welding location Wa of the three-dimensional workpiece W by controlling the robot arm 3. Then, the laser beam LB oscillated by the fiber laser oscillator 15 is transmitted to the welding head 5 through the transmission fiber 13. The laser beam LB transmitted to the welding head 5 is converted into parallel light by the collimator lens 17 and scanned while being deflected by the galvano scanner 21 in the first scanning direction and the second scanning direction. The laser beam LB scanned while being deflected is collected by the Fθ lens 33 and irradiated to the welding spot Wa from the emission opening 9 of the head body 7 through the protective glass 35. Thereby, the solid workpiece W is laser-welded. During the operation of the fiber laser oscillator 15, the welding head 5 can be moved integrally with the robot arm 3 along the welding location Wa.

By supplying air from the air supply source 47 to the air passage 45 during laser welding, the air A is ejected from the first nozzle slit 51 toward the optical axis of the laser beam LB on the irradiation direction side of the laser beam LB. At the same time, air B is ejected from the plurality of second nozzle holes 53 along the irradiation direction of the laser beam LB. Then, the air A ejected from the first nozzle slit 51 is merged on the optical axis of the laser beam LB toward the welding spot Wa, and the air A ejected from the plurality of second nozzle holes 53 is the laser beam LB. While surrounding the air A that merges on the optical axis of the head, it goes around the welded portion Wa.

That is, since the first nozzle slit 51 is formed in the air nozzle 37 so as to surround the optical axis of the laser beam LB, and the first nozzle slit 51 communicates with the air passage 45, the first nozzle slit 51 is ejected from the first nozzle slit 51. The air A merges on the optical axis of the laser beam LB and travels toward the welding location Wa. Thereby, even if the shape of the solid workpiece W is complicated, the retention of fume between the welding head 5 and the solid workpiece W can be sufficiently suppressed.

In addition, a plurality of second nozzle holes 53 are formed at positions outside the first nozzle slit 51 in the radial direction so as to surround the optical axis of the laser beam LB, and the plurality of second nozzle holes 53 are formed in the air passage 45. Therefore, the air B ejected from the plurality of second nozzle holes 53 travels around the welding point Wa while surrounding the air A that merges on the optical axis of the laser beam LB. As a result, as shown in FIG. 3, when laser welding is performed on the three-dimensional workpiece W from the side, even if the spatter S scatters to the welding head 5 while drawing a parabola from the welding location Wa, the spatter S is transferred to the welding head 5 (the spattering direction of the spatter S can be changed as indicated by the white arrow in FIG. 3).

Therefore, according to the present embodiment, even if the shape of the three-dimensional workpiece W is complicated, the retention of fume between the welding head 5 and the three-dimensional workpiece W can be sufficiently suppressed, so that the fume laser light LB is obtained. The solid workpiece W can be stably laser-welded under stable welding conditions (processing conditions).

Further, when laser welding is performed on the three-dimensional workpiece W from the side, the spatter S can be deflected from the welding head 5 even if the spatter S scatters to the welding head 5 while drawing a parabola from the welding spot Wa. Adhesion of the sputter S to the glass 35 can be reduced. As a result, the replacement frequency of the protective glass 35 can be greatly reduced.

The welding head 5 according to the present embodiment, the welding head 101 according to the first prior art example (see FIG. 5B), and the welding head 111 according to the second prior art example (see FIG. 6B) are used. Then, laser welding was performed on the solid workpiece W from the side. FIG. 4 shows the relationship between the number of welded solid workpieces W and the number of spatters attached to the protective glass 35. As shown in FIG. 4, when the welding head 5 is used, the number of spatters can be significantly reduced as compared with the case where the welding head 101 and the welding head 111 are used. Note that the number of pulse shots required to weld one solid workpiece W is set to 3960 times, and an external blower was used only in the case of the first prior art example.

The present invention is not limited to the above embodiment, and can be implemented in various modes.

Claims

A laser welding head that is used in a laser welding apparatus that performs laser welding on a workpiece and irradiates a laser beam toward a welding portion of the workpiece,
A hollow head body optically connected to a laser oscillator, formed at the tip with an emission opening for emitting laser light;
A protective glass that is detachably provided on the head body and covers the emission opening,
An annular gas nozzle provided on the workpiece side from the protective glass, and
A gas passage connectable to a gas supply source is formed inside the gas nozzle,
A first nozzle that ejects gas toward the optical axis of the laser beam on the irradiation direction side of the laser beam and a second nozzle that ejects gas along the irradiation direction of the laser beam are formed on the gas nozzle. Has been
The first nozzle communicates with the gas passage and is formed to surround the optical axis of the laser beam,
The laser welding head, wherein the second nozzle communicates with the gas passage and is formed to surround the first nozzle at a position radially outward from the first nozzle.
The laser welding head according to claim 1,
The first nozzle is an annular first nozzle slit, a plurality of first nozzle holes formed at intervals in the circumferential direction, or a plurality of arc-shaped first nozzles formed at intervals in the circumferential direction. Slit,
The second nozzles are a plurality of second nozzle holes, annular second nozzle slits formed at intervals in the circumferential direction, or a plurality of arc-shaped second nozzles formed at intervals in the circumferential direction. A laser welding head that is a slit.
A laser welding apparatus,
The laser welding head according to claim 1 or 2,
A moving device that is mounted with the laser welding head and moves the laser welding head so that the laser welding head approaches the workpiece from the side or moves the laser welding head away from the workpiece laterally; Laser welding equipment provided.
A gas nozzle for a laser welding head,
A gas passage formed therein and connectable to a gas supply source;
A first nozzle that ejects gas toward the optical axis of the laser beam on the irradiation direction side of the laser beam;
A second nozzle that ejects gas along the irradiation direction of the laser beam,
The first nozzle is formed to communicate with the gas passage and surround an optical axis of the laser beam;
The gas nozzle, wherein the second nozzle communicates with the gas passage and is formed at a position radially outward from the first nozzle so as to surround the first nozzle.
A gas nozzle for a laser welding head according to claim 4,
The first nozzle is an annular first nozzle slit, a plurality of first nozzle holes formed at intervals in the circumferential direction, or a plurality of arc-shaped first nozzles formed at intervals in the circumferential direction. Slit,
The second nozzles are a plurality of second nozzle holes, annular second nozzle slits formed at intervals in the circumferential direction, or a plurality of arc-shaped second nozzles formed at intervals in the circumferential direction. A gas nozzle that is a slit.