JP2003136269A - Laser beam machining device and its method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laser beam machining device and its method that facilitate laser beam machining for a shape-changing workpiece. SOLUTION: The laser beam machining device 10 is equipped with a copying mechanism which follows up the shape change of a workpiece to copy it easily and which always keeps a distance constant between a condensing lens 15 and the workpiece 18, an adjusting means 38 which constantly holds a path length for supplying a filler material, and a nozzle tip 26 which has an outer diameter D at least twice the diameter d of a laser guiding hole and which has a nozzle 52 for supplying the filler material to a laser beam irradiation part 36. The device injects shielding gas 47 in the direction coaxial with a laser beam 12 from near a laser beam emitting port 23 toward the laser beam irradiation part 36 of the workpiece 18. As a result, the device forms a stable shielding gas atmosphere 49 even if the shape changing workpiece 18 is located underwater, thereby enabling the filler material to be steadily fed to the laser beam irradiation part 36, preventing the surface oxidation of a weld bead, and enabling stable laser beam machining.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser machining technique for performing laser overlay welding and surface modification by remote control in maintenance work of internal structures of a nuclear reactor, and more particularly, to a shape change submerged in reactor water. The present invention relates to a laser processing apparatus and a laser processing method for performing laser processing on a structure having the same.

[0002]

2. Description of the Related Art A conventional laser processing apparatus 1 is shown in FIG.
According to FIG. 7, in the laser welding using the filler wire 2, the laser processing apparatus 1 has a three-dimensional processing machine that includes an emission optical system 4 that focuses the laser light and irradiates the laser processing target 3 with the laser light. Alternatively, the processing machine 5 such as a robot is provided. The processing machine 5 controls the position of the emission optical system 4 in response to a change in the shape of the laser processing target 3 and performs laser welding while moving the emission optical system 4.

[0003]

However, this laser processing method requires a sensor for detecting a change in the shape of the laser processing target 3 and a controller for controlling the position of the emission optical system 4, which is required in the maintenance work of the existing plant. However, it is difficult to perform laser processing of a narrow part such as inside a pipe by remote control. Further, the structure provided in the existing plant may be submerged in water, and it is necessary to perform stable laser processing even in water.

The present invention has been made in consideration of the above-mentioned circumstances, and facilitates laser processing of a laser processing object having a shape change, and performs stable laser processing even when the processing object is submerged in water. An object is to provide a laser processing device and a method thereof.

[0005]

In order to solve the above-mentioned problems, a laser processing apparatus according to the present invention has a laser oscillating device which oscillates a laser and a laser oscillating device from which the laser oscillating device is provided. A first lens optical system for collimating the oscillated laser light into parallel light; and a condenser lens optical system for condensing the laser light collimated through the first lens optical system onto a laser processing object. An output optical system for holding the condenser lens optical system while irradiating a laser processing object with laser light condensed by the condenser lens optical system,
In a laser processing apparatus comprising a solubilizing material supply means for supplying a solubilizing material to a laser beam irradiation portion of the laser beam from the emitting optical system, the emitting optical system is moved to follow the shape change of the laser processing target. A feature is that a copying mechanism is provided, and the distance between the condenser lens optical system and the laser processing target is always kept constant by this copying mechanism.

In order to solve the above-mentioned problems, in the laser processing apparatus according to the present invention, as described in claim 2, the copying mechanism causes the solubilizing material supply path from the solubilizing material supplying means to the solubilizing material supplying position. It is characterized in that a solubilizing material supply path length adjusting means for keeping the length constant is provided.

In order to solve the above-mentioned problems, in the laser processing apparatus according to the present invention, as described in claim 3, the emitting optical system causes the laser beam of the laser processing object to be processed from near the laser beam emitting port. It is characterized in that a gas jetting means for jetting a gas in the direction coaxial with the laser beam toward the irradiation part is provided, and the laser processing in water is performed by the gas jetting means.

Further, in order to solve the above-mentioned problems,
A laser processing apparatus according to the present invention is characterized in that, as described in claim 4, the emitting optical system includes a metal mesh that covers the laser beam emitting portion at the laser beam emitting port.

On the other hand, in order to solve the above-mentioned problems, in the laser processing apparatus according to the present invention, as described in claim 5, a laser beam which allows the laser beam to pass through the laser beam emission port of the emission optical system. A nozzle tip having a guide hole is provided, and the outer diameter of the nozzle tip is formed to be at least twice as large as that of the laser light guide hole.

Further, in order to solve the above-mentioned problems, in the laser processing apparatus according to the present invention, as described in claim 6, the nozzle tip is formed on the inner circumferential surface of the laser light guide hole in the circumferential direction. It is characterized by comprising a solubilizing agent supply nozzle for supplying the solubilizing agent to the laser beam irradiation portion of the laser processing target.

In the laser processing apparatus configured as described above, it is possible to stably supply the solubilizing material to the laser light irradiation portion of the laser processing target even for the laser processing target having a shape change, and stable. Enables laser processing. Further, since a stable shield gas atmosphere can be formed in water, it is possible to perform stable laser processing even when the object to be laser processed is in water.

In order to solve the above-mentioned problems, the laser processing method according to the present invention comprises, as described in claim 7, a parallel light forming step of converting output laser light oscillated from a laser oscillator into parallel light. The converging step of converging the collimated output laser light with the condensing lens optical system and the irradiation step of irradiating the laser processing target object with the condensed output laser light from the emission optical system are sequentially executed. When a laser processing object is irradiated with output laser light, a solubilizing material is supplied to the laser beam irradiation part to perform laser processing on the laser processing object. Position adjustment step for keeping the distance between the condensing lens optical system and the laser processing object constant by moving the exiting optical system, and the length of the solubilizing agent supply path to the solubilizing agent supplying position for supplying the solubilizing agent Keep constant Run a reduction material supply path length adjusting step simultaneously and performing laser processing of the laser processing object.

Further, in order to solve the above-mentioned problems, the laser processing method according to the present invention is, as described in claim 8, a laser which is irradiated toward a laser processing object during the irradiation step. It is characterized by comprising a gas ejection step of ejecting gas in a direction coaxial with light, and performing the laser processing by simultaneously performing the irradiation step of irradiating a laser processing target object with laser light and the gas ejection step.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a laser processing apparatus and a laser processing method thereof according to the present invention will be described below with reference to the drawings.

[First Embodiment] FIG. 1 is a schematic view showing a first embodiment of a laser processing apparatus according to the present invention.

The laser processing apparatus 1 shown in the first embodiment
Reference numeral 0 indicates a laser oscillation device 11 for oscillating a laser, and a first lens optical system 13 for forming parallel light on the optical path of the output laser light 12 oscillated by the laser oscillation device 11. Reflection mirror 14 that changes the direction of parallel light
And a condenser lens 15 for condensing parallel light. Further, the laser processing apparatus 10 holds the condenser lens 15 of the condenser lens optical system 16 and irradiates the laser processing target (hereinafter referred to as target) 18 with the condensed output laser light 12 The emitting optical system 19 and the solubilizing material supply means 21 for supplying the filler wire 20 as the solubilizing material.

Emission optical system 1 in laser processing apparatus 10
Reference numeral 9 denotes a lens holder 22 which holds the condenser lens 15, a slide nozzle 24 which holds the lens holder 22 concentrically and has a laser light emission port 23, and an output laser beam 12 from the laser beam emission port 23. And a disk-shaped nozzle tip 26 having a possible laser light guide hole 25.

At the time of laser processing in the laser processing apparatus 10, the output laser light 12 oscillated by the laser oscillator 11 is converted into parallel laser light 12 through the first lens optical system 13, and the parallel laser light 12 is generated. The light 12 is reflected by the reflection mirror 14 at 90 ° and is output to the object 18 Laser light 1
Irradiate 2.

Further, even if the object 18 has a change in shape, the copying mechanism 28 of the laser processing apparatus 10 allows
It is possible to perform stable laser processing.

The copying mechanism 28 is a mechanism for moving the emission optical system 19 in accordance with the shape change of the object 18. The slide nozzle 24 included in the emitting optical system 19 includes
Since the lens holder 22 is fixed and the lens holder 22 holds the condenser lens 15, the slide nozzle 24 integrally holds the condenser lens 15 via the lens holder 22. . The slide nozzle 24 is axially slidably supported in the cylindrical casing 29, is constantly urged by the spring 30 toward the target 18, and is constantly pushed toward the target 18.

Accordingly, by rolling the roller 31 provided in the nozzle tip 26 of the laser processing apparatus 10, the object 18
When it is moved up, the emission optical system 19 follows the shape change of the object 18, and the slide nozzle 24 of the emission optical system 19 follows the surface of the object 18 to move the condenser lens 1
5 and the object 18 are always kept constant.

On the other hand, the solubilizing material supply means 21 supplies the solubilizing material during the laser processing. The solubilized material supply means 21 has a filler wire 20 as a solubilized material, and this filler wire 20 passes through a wire guide tube 33, a wire supply path 34, and a wire supply hole 35 as a solubilized material supply path, and a laser beam irradiation section. 36.

The wire supply passage 34 is formed so as to extend substantially axially between the slide nozzle 24 and the lens holder 22, and the wire supply hole 35 is provided in the nozzle tip 26, and the wire supply hole 35 is supplied. The mouth side faces inward in the radial direction and is obliquely directed so as to intersect the output laser beam 12 on the object 18.

As described above, according to this embodiment,
The emission optical system 19 also follows the object 18 having a shape change by the copying mechanism 28, and stable laser processing becomes possible.

[Second Embodiment] FIG. 2 shows a second embodiment of the laser processing apparatus 10 according to the present invention.

Laser processing apparatus 10A showing this embodiment
The solubilized material supply means 21 includes a solubilized material supply path length adjusting means (hereinafter, referred to as adjusting means) 38. Adjusting means 38
Since the mechanism other than that is the same as that of the laser processing apparatus 10 shown in FIG. 1, the same reference numerals are given and the description thereof is omitted.

According to FIG. 2, this adjusting means 38 is a drive for feeding a wire reel 39 as a solubilizing material supply means around which a filler wire is wound and a filler wire 20 fed from the wire reel 39 into a wire guide tube 33. A roller 40 and a driven roller 41 that follows the driving roller 40 are provided in opposition to each other, and the driving roller 40 is rotationally driven by a roller driving motor 42. The drive roller 40 and the driven roller 41 are housed in a roller cover 44. This roller cover 44 is
It has a guide hole through which the filler wire 20 passes and is provided in the main body of the laser processing apparatus 10A via a mounting shaft 45.

The mechanism of the adjusting means 38 will be described with reference to FIG. The filler wire 20 from the wire reel 39 is sandwiched between the driving roller 40, the driving roller 40 and the driven roller 41, and is fed out. When the roller driving motor 42 is driven and the driving roller 40 rotates, the filler wire 20 sandwiched between the driving roller 40 and the driven roller 41 is fed into the wire guide tube 33.

When performing laser processing, the laser processing apparatus 10
The output mechanism 19 follows (moves up and down) following the surface shape of the object 18 by the copying mechanism 28 (see FIG. 1).
The slide nozzle 24 and the lens holder 2 shown in FIG.
Since 2 moves up and down (follows) along the shape of the object 18, the wire guide tube 33 attached to the slide nozzle 24 also moves up and down according to the shape of the object 18.

The vertical movement of the wire guide tube 33 is performed by the wire reel 39 from the wire supply position, that is, the laser beam irradiation section 3.
Since the length of the solubilizing material supply path up to 6 is varied, it is not preferable for stable wire supply.

Therefore, as shown in FIG. 2, the wire guide tube 3
3 By providing the stoppers 46a and 46b near the upper end and sandwiching the roller cover 44, the roller cover 44 is attached to the mounting shaft 45 in response to the vertical movement of the wire guide tube 33.
It is designed to be able to move up and down around the axis.

As described above, according to this embodiment,
The roller cover 4 corresponds to the vertical movement of the wire guide tube 33.
4 moves up and down about the mounting shaft 45,
The length of the solubilized material supply path from the wire reel 39 to the wire supply position is always constant, and stable supply of the filler wire 20 to the molten portion is possible.

[Third Embodiment] FIG. 3 shows a third embodiment of the laser processing apparatus 10 according to the present invention, and shows an example of underwater laser welding using the laser processing apparatus 10. In the present embodiment, parts that are not different in mechanism from the laser processing apparatus 10 shown in FIG. 1 are designated by the same reference numerals and description thereof will be omitted.

As shown in FIG. 3, the emission optical system 19 provided in the laser processing apparatus 10B is provided with a gas ejection means 48 for flowing an inert gas as a shield gas 47 in the direction coaxial with the output laser beam 12, and this gas ejection is performed. The shield gas 47 ejected from the means 48 forms a shield gas atmosphere 49 at the tip of the nozzle tip 26. And
Laser welding is performed within this shield gas atmosphere 49.

The nozzle tip 26 is plated with gold to form a dome-shaped metal mesh or punch plate 50.
By attaching, the shield gas 47 flowing in the direction coaxial with the output laser beam 12 is jetted out into the water, and the shield gas 47 becomes fine bubbles 51 in the water to stabilize the shield gas atmosphere 49.

As described above, according to this embodiment,
Since the stable shield gas atmosphere 49 can be formed, stable laser processing can be performed even in water.

[Fourth Embodiment] A laser processing apparatus 10 according to a fourth embodiment of the present invention will be described with reference to FIGS. 4 and 5. Since the overall configuration is the same as that of the laser processing apparatus 10 shown in FIG. 1, the same reference numerals are given and description thereof is omitted.

4A and 4B show the shape of the nozzle tip 26 in the laser processing apparatus 10C. Figure 4
According to (A) and (B), this nozzle tip 26
Is a disk shape having a laser light guide hole 25 through which the output laser light 12 passes at the center. By making the nozzle tip outer diameter D twice or more the laser guide hole diameter (nozzle tip inner diameter) d, it is possible to prevent the surface oxidation of the welding beads caused by the disturbance of the shield gas atmosphere 49.

As a concrete example, the laser output is 1 k.
W, welding speed 0.3 m / min, shield gas flow 60
In laser welding under the condition of 1 / min, the ratio of the nozzle tip outer diameter D and the laser guide hole diameter d was changed, and the length l of the oxidized surface portion with respect to the welding bead total length L was investigated. Shown in A). A schematic view of the welding beads for laser welding is shown in FIG. 5 (B).

According to FIG. 5A, the nozzle tip outer diameter D
And the laser guide hole diameter d is 2 or more, that is, if the nozzle tip outer diameter D is twice or more the laser guide hole diameter d, the length 1 of the surface oxidized portion of the weld bead is equal to the total length L of the weld bead. Is almost 0%, indicating that the surface of the weld bead is not oxidized.

As described above, according to this embodiment,
It is possible to prevent the surface oxidation of the welding beads caused by the disturbance of the shield gas atmosphere 49.

[Fifth Embodiment] FIG. 6 shows a laser processing apparatus 10 according to a fifth embodiment of the present invention. Since the overall configuration is the same as that of the laser processing apparatus 10 shown in FIG. 1, the same reference numerals are given and description thereof is omitted.

FIG. 6 shows an example in which the disk-shaped nozzle tip 26 of the laser processing apparatus 10D is provided with the solubilizing agent supply nozzle 52. According to FIG. 6, the solubilizing agent supply nozzle 52 is provided on one circumferential surface of the laser light guide hole 25 of the nozzle tip 26 in the circumferential direction. The laser processing apparatus 10D is provided with the solubilizing material supply nozzle 52 on the circumferential surface of the laser light guide hole 25 of the nozzle tip 26, so that the shield gas atmosphere 49 formed in the vicinity of the laser light irradiation unit 36 is provided.
It is possible to stably supply the filler wire 20 as the solubilizing material to the laser light irradiation section 36 without disturbing the temperature.

As described above, according to this embodiment,
The filler wire 20 can be accurately supplied to the laser light irradiation unit 36 without disturbing the shield gas atmosphere 49 formed in the vicinity of the laser light irradiation unit 36 by the solubilizing material supply nozzle 52, and stable laser processing can be performed. Become.

[0045]

In the laser processing apparatus according to the present invention, the laser processing apparatus easily follows the change in the shape of the object,
Since the distance between the condensing lens and the object and the length of the solubilizing agent supply path are kept constant, the solubilizing agent is stably supplied to the laser light irradiation section, stable laser processing is possible, and a dome-shaped metal mesh is provided. As a result, a stable shield gas atmosphere can be formed and stable laser processing can be performed even in water.

Further, the surface oxidation of the welding bead due to the disturbance of the shield gas atmosphere is prevented, and stable laser processing can be performed without disturbing the shield gas atmosphere.

On the other hand, in the laser processing method according to the present invention,
The position adjustment process of the condenser lens system for keeping the distance between the condenser lens system and the object constant according to the shape change of the object, the solubilizing agent supply means, and the solubilizing agent supply path length to the solubilizing agent supply position. By performing the solubilizing material supply path length adjusting step for keeping the above constant at the same time, stable laser processing becomes possible. At the same time as the laser irradiation process, a stable shield atmosphere is formed by performing a gas ejection process that ejects a shield gas in the direction coaxial with the laser light that is irradiated toward the target object, and laser processing that is stable even in water. Is possible.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a laser processing apparatus according to the present invention.

FIG. 2 is a schematic diagram of a solubilized material supply path length adjusting means.

FIG. 3 is a schematic view of underwater laser welding.

FIG. 4A is a schematic sectional view of a nozzle tip shape,
FIG. 4B is a schematic plan sectional view taken along the line IV-IV in FIG.

FIG. 5A is an explanatory view illustrating the relationship between the nozzle tip shape and the welding bead surface oxidation in underwater laser welding;
(B) is a figure which shows a welding bead surface.

FIG. 6 is a schematic view showing the position of a solubilizing material supply nozzle.

FIG. 7 is a schematic configuration diagram of a conventional laser processing apparatus.

[Explanation of symbols]

10 Laser processing equipment 11 Laser oscillator 12 laser light 13 First lens optical system 14 Reflection mirror 15 Condensing lens 16 Condenser lens optical system 18 Target 19 Output optical system 20 filler wire 21 Solubilizing agent supply means 22 Lens holder 23 Laser emission port 24 slide nozzle 25 Laser light guide hole 26 nozzle tips 28 Copying mechanism 29 Cylindrical casing 30 spring 31 Laura 33 wire guide tube 34 Wire supply path 35 Wire supply hole 36 Laser light irradiation part 38 Adjustment means 39 wire reel 40 drive roller 41 Driven roller 42 Roller drive motor 44 Roller cover 45 mounting shaft 46a, 46b clasp 47 Shield gas 48 Gas ejection means 49 Shield gas atmosphere 50 metal mesh 51 air bubbles 52 Solubilizing agent supply nozzle

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Masataka Tamura             2-4 Suehiro-cho, Tsurumi-ku, Yokohama-shi, Kanagawa               Toshiba Keihin Office (72) Inventor Hidenori Takahashi             8th Shinsugita Town, Isogo Ward, Yokohama City, Kanagawa Prefecture             Ceremony company Toshiba Yokohama office F-term (reference) 4E068 BB02 CA12 CB05 CE05 CH03                       CJ08

Claims (8)

[Claims] 1. A laser oscillating device for oscillating a laser, a first lens optical system for collimating a laser beam oscillated by the laser oscillating device, and a parallel light via the first lens optical system. A condensing lens optical system that condenses the laser light that has become a laser processing target object, and a laser beam that is condensed by the condensing lens optical system while holding the condensing lens optical system to the laser processing target object. In a laser processing apparatus provided with an emitting optical system for irradiating and a solubilizing material supplying means for supplying a solubilizing material to a laser beam irradiation part of the laser light from the emitting optical system, in response to a change in shape of a laser processing object, A laser processing apparatus provided with a copying mechanism for moving an emission optical system to follow and keeping a constant distance between the condenser lens optical system and a laser processing object by the copying mechanism. 2. The profiling mechanism comprises solubilizing material supply path length adjusting means for keeping the solubilizing material supply path length from the solubilizing material supplying means to the solubilizing material supply position constant.
The laser processing device described. 3. The emission optical system includes gas ejection means for ejecting gas in the direction coaxial with the laser light toward the laser light irradiation portion of the laser processing target from the vicinity of the laser light emission port,
The laser processing apparatus according to claim 2, wherein laser processing in water is performed by the gas jetting means. 4. The laser processing apparatus according to claim 2, wherein the emitting optical system is provided with a metal mesh that covers the laser light emitting portion at the laser light emitting port. 5. The emission optical system includes a nozzle tip having a laser light guide hole through which a laser light can pass, the outer diameter of the nozzle tip being at least twice as large as that of the laser light guide hole. The laser processing apparatus according to claim 2, wherein 6. The nozzle tip is provided with a solubilizing agent supply nozzle for supplying a solubilizing agent to a laser beam irradiating portion of a laser processing object on an inner circumferential surface of a laser beam guide hole in a circumferential direction. Item 2. A laser processing device according to item 2. 7. A step of forming a parallel light beam that collimates an output laser beam emitted from a laser oscillator, a step of condensing the collimated output laser beam by a condenser lens optical system, and a condensing step. An irradiation step of irradiating the laser processing target with the output laser light thus generated from the emission optical system is sequentially performed, and when irradiating the laser processing target with the output laser light, a solubilizing material is supplied to the laser light irradiation unit, In a laser processing method for performing laser processing on an object to be laser processed, the emission optical system is moved following the shape change of the object to be laser processed, and the distance between the condenser lens optical system and the object to be laser processed is changed. Laser processing of the laser processing target is performed by simultaneously executing the position adjusting process for keeping constant and the solubilizing agent supply path length adjusting step for keeping the solubilizing agent supply path length up to the solubilizing agent supply position for supplying the solubilizing agent constant. Special Laser processing method to be. 8. The irradiation for irradiating a laser beam on a laser processing target object, comprising a gas ejection step for ejecting a gas in a direction coaxial with a laser beam for irradiation on the laser processing target object in the irradiation step. The laser processing method according to claim 7, wherein the laser processing is performed by simultaneously performing the step and the gas injection step.