JPH09182983A - Irradiating device for laser beam welding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an irradiating device for welding which can be inserted for use in an extremely narrow groove, which cools the optical fiber so as to prevent damage due to overheating and which enables laser welding in all postures. SOLUTION: The device is provided with an optical fiber 1 for introducing a laser beam, sheath body 2 for storing the optical fiber, and a filler mechanism 3; the device is so structured that the optical fiber is cooled by an assist gas 6 injected through a hole 24 formed along the optical fiber and between the sheath body and the optical fiber, and that the tiller mechanism feeds a tiller wire 7 into the luminous flux of the laser beam 5 emitted through the optical fiber.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a small-sized laser welding irradiator capable of handling a high-power laser of an optical fiber light guide type, and more particularly to an ultra-fine laser welding capable of performing narrow groove welding. Irradiator.

[0002]

2. Description of the Related Art Conventionally, as a method of welding a narrow groove for a thick plate or the like,
There has been TIG welding (Tungsten Inert Gas Welding) in which an arc is generated between a tungsten electrode and a base material in an inert gas atmosphere, and a welding rod is inserted into the arc to perform welding.
However, in TIG welding, the welding angle must be set sufficiently large because the welding head needs to be welded close to the large upper welding portion. Furthermore, the size of the device is large and the power supply device needs to be installed near the welding torch, which makes the handling complicated.

In recent years, the performance of transmission optical systems such as laser oscillators and lenses has been remarkably improved.
The beam handling optical system can be simplified, for example, by using a thin and flexible optical fiber of mm.
Also in the condensing optical system, since the condensing spot at the processing point has been miniaturized, a high-flexibility welding system using an optical fiber has been constructed to perform high-power laser welding.

Welding in all postures is required at the laying of pipelines and at narrow places, and in order to make this possible, a fiber-guided laser that can be flexibly routed is advantageous. Such a narrow groove laser welding method is disclosed in, for example, JP-A-62-220293 and JP-A-4-157.
No. 077 also discloses it.

However, in the condensing optical system used for the narrow groove laser welding, the laser beam emitted from the optical fiber is sufficiently widened and then focused by a large-diameter lens so that the light beam emitted from the fiber is well condensed and the focusing point is reduced. It was usual to configure as follows. In such a configuration, since it is necessary to reduce aberrations, a combination lens system using a plurality of lenses has to be used to increase the diameter of the processing head. In addition, in laminated welding using a filler wire with a laser, it is common to adjust the opening angle of the groove to the divergence angle of the beam in order to prevent the laser beam focused by the lens from being kicked by the groove. A long-focus processed lens is used to reduce the groove angle corresponding to a deep groove. In this case, the processing head becomes large, and it is necessary to separate it from the welding target in order to cope with a narrow groove, and it is difficult to weld at a narrow place.

FIG. 11 shows an example of a conventional laser welding head. Laser light is emitted from the end face of the optical fiber fixed to the upper end in the figure with a certain spread angle. The laser light spread to an appropriate size is condensed by a condensing optical system including a combination lens. The position of the last-stage lens can be changed in the axial direction, and the position of the focal point can be adjusted slightly. As a design example, for a laser welding head using a 1.3 kW YAG laser,
A light collecting optical part having a diameter of about 100 mm and a length of about 300 mm is obtained.

[0007] The laser light that has exited the condenser lens portion penetrates into a groove provided at the butted portion of the welding base material while converging. If the width of the groove is small, the peripheral edge of the laser beam is reflected by the edge of the groove and does not reach the inside. Therefore, in order to allow the laser beam having a converging angle to fall within the groove width, the width is usually required to be about 15 mm, depending on the plate thickness, and distortion due to filling the welding material into the wide groove width is also a problem. Was sometimes As described above, the conventional welding torch system has a problem that the torch size is large and it is difficult to weld a thick plate in all postures.

[0008] High-power laser welding makes it possible to weld a thick plate, but if the posture is upright or upward, the weld metal drips and it is difficult to weld in all positions. Incidentally, the thickness of the plate capable of supporting the molten metal by surface tension in steel welding is about 10 mm or less. In order to realize full-position welding of a thick plate, the amount of weld metal per pass must be at most about 3 mm, so that multi-layer welding is required to weld a thick plate. In ordinary arc welding, in order to realize this, the amount of welding is reduced and the lamination welding is performed in a state in which no dripping occurs.

Further, as described above, when performing lamination welding or the like in a groove, if the groove angle is smaller than the focusing angle of the laser beam, the periphery of the laser beam is kicked by the edge of the groove. Because the energy of the laser beam does not reach the depth of the groove,
It was necessary to make the groove angle larger than the convergence angle of the laser beam, so that the groove width could not be reduced, and there was a limit to narrow groove processing. Further, in order to lengthen the effective portion having the energy density required for processing, it is necessary to reduce the spread of the light beam, and the distance from the exit end of the optical fiber to the lens must be increased.

Further, if a quartz lens is used as the light condensing system, it is difficult to cool the lens, so that radiant heat may cause overheating and damage to the coating and damage to the lens itself. In addition, distortion due to heat causes problems in the optical system.

[0011]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a small size laser welding irradiator which can be used by being inserted into a narrow groove. An object of the present invention is to provide a fiber-guided laser welding irradiator capable of performing good welding and enabling laser welding using an extremely narrow groove in all positions.

[0012]

In order to solve the above problems, a laser welding irradiator of the present invention comprises an optical fiber for guiding a laser beam, a sheath for accommodating the optical fiber, and a filler supply mechanism. The auxiliary gas is ejected through a hole formed along the optical fiber with the optical fiber, and the filler supply mechanism is configured to feed the filler wire into the light flux of the laser emitted from the optical fiber. And Further, in the laser welding irradiator of the present invention, the tip of the sheath body is projected from the tip of the optical fiber, and a part of the laser light emitted from the optical fiber is reflected by the inner wall of the sheath body to be focused and energy of the laser light is You may make it reach a distant place.

Further, the laser welding irradiator of the present invention is
A microlens with a short focal length is provided at the tip of the optical fiber, the sheath also covers the microlens, and the filler supply mechanism supplies the tip of the filler wire into the laser beam condensed by the microlens. You may. A gradient index lens may be used instead of the micro lens. Further, a cylindrical lens whose central axis is orthogonal to the laser optical axis may be used instead of the microlens, and the filler wire may be supplied in the longitudinal axis direction of the laser beam linearly converted by the cylindrical lens.

Further, the irradiator for laser welding of the present invention comprises:
A gas nozzle for spraying a protective gas from the lateral direction between the tip of the filler wire and the tip of the sheath may further be provided, and the sheath, the gas nozzle, and the filler wire may be arranged in a line. Further, the laser welding irradiator of the present invention has a mechanism for extruding the sheath, so that the sheath itself is melted by laser light emitted from the optical fiber and fused with the target base material. Good.

Furthermore, at least one second optical fiber is provided in addition to the first optical fiber for guiding the laser light, and the surface of the base material to be welded is preheated using the laser light emitted from the second optical fiber. Alternatively, the filler wire may be melted using laser light emitted from the first optical fiber to fill the welded portion. Further, a monitoring optical fiber having the fiber tip directed toward the welding portion may be provided.

Further, the moving mechanism of the present invention is provided with a rotating jig that rotates in all postures, and by mounting the laser welding irradiator on the rotating jig, it is possible to irradiate laser light in all directions. It is. In the laser welding irradiator of the present invention, it is preferable that the base material of the optical fiber is quartz and that the laser light of an iodine laser is used.

According to the laser welding irradiator of the present invention, an optical fiber, a sheath, and a filler supply mechanism are provided, an auxiliary gas is jetted through a hole formed along the optical fiber, and the filler supply mechanism is provided with a laser beam. The tip of the filler wire is fed into the light beam. The laser welding irradiator is heated by the radiation emitted when the welding base metal and filler wire are melted by the laser energy and tries to raise the temperature.However, an auxiliary gas is used to protect the surface of the welding base metal and to assist welding and to assist the welding. Because it flows along
The optical fiber is cooled by the auxiliary gas to avoid the temperature rise.
Further, since it is sufficient that there is a space between the sheath and the optical fiber for allowing the auxiliary gas to pass, the diameter of the sheath may be slightly larger than the outer diameter of the optical fiber, and the finished outer diameter is, for example, 2.5.
mm and extremely thin. Therefore, even if the groove is narrow, the irradiator body can be inserted into the groove and welded, so that there is no restriction on the groove angle as in the prior art, and the present invention is applied to an extremely narrow groove of, for example, about 4 mm. Can be.

Further, the filler wire is inserted into the laser beam emitted from the tip of the optical fiber, melted by the energy of the laser light, and fused with the welding base material. At this time, plasma is generated between the filler wire and the tip of the irradiator, but the auxiliary gas blown from the periphery of the optical fiber blows off the plasma, so that the particles converted into plasma adhere to the end face of the irradiator and stain the surface of the tip of the optical fiber. Nothing. In this way, by flowing an inert gas such as argon Ar, helium He, or nitrogen N ₂ through the welding head during processing, the head including the lens and the like can be cooled, and at the same time, between the workpiece and the head. The generated plasma-like metal particles are blown away to prevent the melt from adhering to the head portion, and perform a shielding function to protect the optical system.

Further, in the laser welding irradiator of the second embodiment of the present invention, since the tip of the sheath body projects from the tip of the optical fiber, a part of the laser light emitted from the optical fiber is reflected by the inner wall of the sheath body. . This reflected light is refocused and diverged in front of the optical fiber, so that the reflected light has the same effect as if the radiation surface had advanced forward. Since this reflected light is combined with the laser light emitted directly through the opening of the sheath body, the energy density of the laser beam becomes substantially high, which has the effect of making the energy of the laser light reach farther. Therefore, in the laser welding irradiator of the second embodiment, sufficient welding is possible even if the distance from the filler wire, that is, the distance from the welding base material is increased.

Since the laser welding irradiator of the third embodiment of the present invention is provided with a microlens having a short focal length at the tip of the optical fiber, the laser light emitted from the end face of the optical fiber inside the sheath is once near the focal point. It is collected and diffused again. Therefore, the same effect as when the emission surface of the laser light has advanced to the front occurs, since the range in which the energy of the laser light can be used for welding spreads farther, it is possible to insert the filler wire further away. It becomes easy to avoid the influence of plasma generated due to the melting of the filler wire. The auxiliary gas blown along the optical fiber can be injected from a slot formed in the inner wall of the sheath surrounding the microlens.

If the microlens is a gradient index lens, not only can a very small irradiator be constructed, but also the manufacture and assembly of the lens can be facilitated and the manufacturing process can be simplified, so that the irradiator is economically economical. Can be manufactured.
Further, when a cylindrical lens whose central axis is orthogonal to the laser optical axis is attached to the tip of the optical fiber, the laser light is diffused in a direction perpendicular to the central axis of the cylindrical lens, so that the irradiation range becomes an elliptical shape. By advancing the welding while supplying the filler wire in the long axis direction of the irradiation range, the welding base material and the filler wire can be sufficiently preheated and fused at an appropriate temperature to perform high-quality welding.

The laser welding irradiator further includes a gas nozzle for blowing a protective gas from the lateral direction between the tip of the filler wire and the tip of the sheath, and the sheath, the gas nozzle, and the filler wire are arranged in a line. Since the gas ejected from the gas nozzle blows out the plasma generated between the sheath tip and the filler wire reliably from the vertical direction, it is possible to prevent the end face of the optical fiber and the lens surface at the tip of the sheath from being contaminated with flying particles. .

Further, in a device having a mechanism for extruding the sheath, wherein the sheath itself is melted by laser light emitted from the optical fiber and fused with the target base material, the sheath forms a consumable member. Therefore, the size of the head is further reduced, and welding can be performed by inserting the head into an extremely narrow portion. Further, in the apparatus having a second optical fiber for preheating in addition to the first optical fiber for guiding the laser light for welding, the base material to be welded is preheated with the laser light from the second optical fiber to pre-form the surface of the base material. Since the wettability of the surface is improved by light melting, the molten filler metal fits well into the surface of the material and forms a good weld having no unmelted portion with the base material.

The one provided with the monitoring optical fiber with the fiber tip directed to the welded portion can monitor the welded portion remotely via a monitor or the like during welding and check the target position without changing the size of the irradiator so much. It can be used to grasp the state of welding by observing the state of light emission due to dripping or melting. In addition, according to the moving mechanism of the present invention, which includes a rotating jig that rotates in all postures and mounts the laser welding irradiator on the rotating jig, the laser beam can be irradiated in all directions. Laying and welding in narrow places can be realized.

In the laser welding irradiator in which the base material of the optical fiber is quartz, the quartz has a wavelength of 1.
Since a 315 μm iodine laser beam is well transmitted, a high-power iodine laser can be used for welding to obtain a laser welding head that generates strong energy. Furthermore, since iodine lasers can be transmitted over long distances using a quartz-based optical fiber, instead of having a laser generator for each laser processing device, a large iodine laser generator is installed in one corner of the processing plant and installed. By using a method in which an optical fiber network as a starting point is set up in the factory and laser energy is distributed to the laser processing head of the present invention provided at each processing position via an optical distributor, a large output is obtained at various points in the factory. Laser processing using laser energy can be enabled.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION An irradiator for laser welding according to the present invention comprises:
A predetermined ratio of an optical fiber that guides a powerful laser beam generated by the laser device, a sheath body that houses the optical fiber and has a hole that forms a passage along the optical fiber, and a filler wire that is a consumable member for welding the base material is used. And a filler supply mechanism for supplying the gas through the hole between the sheath and the optical fiber, and ejecting an auxiliary gas such as an inert gas supplied from an auxiliary gas holder outside the irradiator. While wrapping the surface of the material and preventing its oxidation, it ensures good welding and also cools the optical fiber, which is heated by radiant heat. At the same time, the filler supply mechanism feeds the tip of the filler wire into the light beam of the laser emitted from the optical fiber, so that the filler wire is melted by the laser energy and the welding base material is welded and welded.

In the irradiator for laser welding of the present invention, the sheath only needs to have a diameter enough to accommodate the optical fiber and to provide a hole through which the auxiliary gas flows, and it is slightly thicker than the optical fiber, for example, an outer diameter of 2.5 mm. It is possible to It should be noted that even a lens system provided with a lens system at the tip can be finished to an outer diameter of about 4 mm by selecting a lens system having a small diameter. Since the tip of the laser welding irradiator of the present invention is extremely narrow as described above, the groove width is formed slightly larger than this, and the tip of the irradiator is inserted into the groove to perform lamination welding on its bottom. You can do so.

In the method of welding by inserting a thin irradiator into a groove as described above, the groove angle is set so that a part of the laser beam converged from a distance is not kicked by the groove. It is not necessary to adjust the convergence angle, and it is sufficient that the width of the groove is slightly larger than the width of the tip of the irradiator. For example, for a laser welding irradiator with a tip outer diameter of 2.5 mm, the groove width is set to 4 even if the offset due to lateral shrinkage due to heat is considered.
mm. The groove width can be set to about 6 mm for a laser welding irradiator having an outer diameter of 4 mm. If the groove width can be reduced, the effect of suppressing a decrease in base material strength due to excessive heat input by welding and a decrease in dimensional accuracy due to welding distortion is great.

If the filler wire is melted near the front surface of an optical system such as an optical fiber or a lens, plasma-generated particles may adhere to the surface and cause a problem. To prevent this, the filler wire can be melted at a position away from the end of the irradiator without reducing the energy of the laser beam. Furthermore, when the sheath is formed of the same metal as the base material, melted by laser light, used for welding the base material, and the depleted portion is supplied by a filler feeding device, a sheath body is provided at the tip of the irradiator. There is no need to separately provide a filler feeder outside, and the tip of the irradiator to be inserted into the groove is only the sheath of the optical fiber. Therefore, the posture of the irradiator can be freely changed within the narrow groove for welding. And all-position welding is facilitated. Hereinafter, an irradiation device for laser welding according to the present invention will be described using embodiments with reference to the drawings.

[0030]

Embodiment 1 FIG. 1 is a partial sectional view showing a use state of a first embodiment of the present invention. FIG. 1A is a front view, and FIG. 1B is a side view. The optical fiber 1 guides a laser beam from a laser device (not shown) such as a YAG laser or an iodine laser capable of generating strong energy, and emits the laser beam 5 with a predetermined spread angle from its tip.

The sheath 2 has an outer diameter of about 2.5 mm, and is provided with a plurality of vertical beams 22 on the inner wall. The optical fiber 1 is held on the central axis to protect the optical fiber 1 from damage, and is formed between the vertical beams. The inert gas 6 such as nitrogen, argon, and helium supplied from a gas supply device (not shown) is caused to flow through the vertical groove 24. The vertical beam 22 may be inserted between the optical fiber 1 and the cylindrical sheath 2 as a spacer, or may be formed on the inner wall of the sheath 2 by broaching or the like.

The filler supply device 3 includes a filler guide tube 3
2 and a feed roller 34. Filler guide tube 3
Reference numeral 2 denotes a smooth curve, and the projection is provided so that the tip is located in front of the tip of the sheath 2, and the tip of the filler wire 7 fed from the feed roller 34 is inserted into the light beam of the laser beam 5. . The filler guide tube 32 is arranged so as to stay outside the light beam of the laser light in order to avoid damage by the laser light.

FIG. 1 shows a state in which a thick plate 4 is butt-welded by a narrow groove welding method using the laser welding irradiator of the present embodiment. The groove 42 has a width of about 4 mm, and a weld layer 44 having several layers already formed is formed at the innermost part. The laser beam 5 emitted from the optical fiber 1
Irradiate and heat the surface of. The laser beam 5 also irradiates and melts the tip of the filler wire 7 supplied from the tip of the filler guide tube 32, adapts to the surface of the heated base material 4, spreads it, and further laminates a single welding layer 44. . The laser beam 5 remains emitted from the optical fiber 1 and dissipates at a considerably large angle, but has sufficient energy to melt them because the distance to the filler wire 7 and the welding base material 4 is short.

The filler wire 7 is a wire of the same material as the base material 4 and is supplied by a feed roller 34 as it is consumed. Since the base material of the optical fiber 1 is made of quartz or the like and is a poor conductor of heat, it is difficult to release the radiant heat received due to the welding operation performed very close to maintain the temperature optimally. Therefore, the optical fiber 1 is cooled by flowing an inert gas 6 having a function of an auxiliary gas for protecting the surface by spraying the surface of the welding base material along the optical fiber 1. Since the shielding gas necessary for welding is used as the cooling gas in this manner, the optical fiber 1 is constantly cooled during welding, and thus has an effect of protecting the irradiator.

When the consumable member 7 and the base material 4 are melted by the laser beam 5, plasma is generated. When the plasma adheres to the surface of the optical fiber 1 and particles are deposited, the end face becomes dirty and the radiation efficiency of the laser beam decreases. The laser light is absorbed in the portion and the quartz fiber is burned. The inert gas 6 also ejects from the tip of the optical fiber 1 and blows off this plasma to also prevent the end face of the fiber from becoming cloudy.
In the drawings, the case where the irradiator is moved in the direction opposite to the filler wire 7 to perform welding is expressed. However, the welding may be performed in such a manner that the welding proceeds in the direction in which the filler wire 7 is supplied. .

[0036]

Embodiment 2 FIG. 2 is a partial sectional view showing a second embodiment of the laser welding irradiator according to the present invention. In the following drawings, elements having the same functions as the elements shown in the above-mentioned figures will be denoted by the same reference numerals, and the description will be simplified. In the second embodiment of the laser welding irradiator according to the present invention, the tip of the optical fiber 1 is pulled in from the tip of the sheath 2, and the inner wall 26 at the tip of the sheath 2 is coated with a substance that reflects laser light. ing.

For this reason, the peripheral portion of the laser beam 5 emitted from the optical fiber 1 is reflected by the inner wall 26 of the sheath, converges, and is radiated again. That is, since the same effect as when the radiation position of the laser beam 5 is advanced is produced, compared to the laser welding irradiator of the first embodiment, the tip of the sheath and the filler wire 7 are provided.
And the distance from the welding base material 4 can be increased. Therefore, the radiation received by the irradiator is reduced, and the optical system is less likely to be contaminated by the plasma generated from the filler wire 7 and the like, so that the gas blowing for cooling and for protecting the optical system may be weak. In addition, as the sheath 2 having an inner wall coated with a laser light reflecting material, for example, gold or silver having a high laser light reflectance is vapor-deposited on an aluminum rod having a low melting temperature, and nickel having a high strength is applied as a structural member thereon. And finally, a pipe obtained by chemically dissolving aluminum can be used.

[0038]

Embodiment 3 FIG. 3 is a partial sectional view showing a third embodiment of the laser welding irradiator according to the present invention. FIG. 4 shows the IV of FIG.
FIG. 4 is a cross-sectional view taken along plane IV. The laser welding irradiator of the third embodiment differs from that of the first embodiment in that a microlens 10 having a short focal length is incorporated at the tip of the sheath 2. The microlens 10 having a short focal length focuses the laser beam 5 emitted from the optical fiber 1 and focuses the laser beam 5 before the welding position. The filler supply device 3 inserts the tip of the filler wire 7 farther from the focal point.
Since the laser light 5 is once focused on the focal point, the same effect as when the radiation position of the laser light 5 is advanced is produced as in the laser welding irradiator of the second embodiment. Therefore, the distance between the tip of the sheath 2 and the filler wire 7 or the welding base material 4 can be increased, the radiation received by the irradiator is small, and the optical system is not easily polluted by the plasma generated from the filler wire 7 and the like. Therefore, the gas blowing for cooling and for protecting the optical system may be weak.

As shown in FIG. 4, a groove 24 is formed in the inner wall of the distal end portion of the sheath body 2 in the axial direction by broaching, and the microlens 10 is inserted into the groove peak 22 and fixed. 6 is ejected.
Instead of processing the sheath 2 to form the groove 24, a holder having an inert gas 6 passage and fixing the microlens 10 at the center axis position of the sheath 2 is provided between the sheath and the microlens. May be interposed. In such a structure, the outer diameter of the sheath body can be suppressed to 4 mm, so that the groove width can be reduced to about 6 mm even if the offset is considered.

[0040]

Embodiment 4 FIG. 5 is a partial sectional view showing a fourth embodiment of the laser welding irradiator according to the present invention. The difference between the laser welding irradiator of the fourth embodiment and that of the third embodiment is that:
Instead of incorporating a short focal length microlens at the tip of the sheath 2, a gradient index lens 12 is incorporated. The inner wall of the sheath 2 has a flow path 24 for coaxially flowing an inert gas with the lens. The use of the small refractive index distribution type lens 12 not only enables the construction of an extremely small irradiator whose outer diameter of the sheath 2 is about 3 mm, but also facilitates the manufacture and assembly of the lens and simplifies the manufacturing process. The irradiator can be manufactured economically. The laser welding irradiator of the fourth embodiment can handle up to a groove width of about 4 mm.

[0041]

Embodiment 5 FIG. 6 is a partial sectional view showing a fifth embodiment of the laser welding irradiator of the present invention. FIG. 7 shows VI of FIG.
It is the arrow line view seen from I-VII. The laser irradiation irradiator of the fifth embodiment differs from that of the third embodiment in that a cylindrical lens 14 is incorporated in the distal end portion of the sheath 2 instead of incorporating a short focal length microlens. The cylindrical lens 14 is set so that the cylindrical axis is orthogonal to the optical axis of the laser beam 5. When the laser beam 5 hits the cylindrical lens 14, the laser beam expands in the direction orthogonal to the cylindrical axis, and the cross section of the laser beam 5 becomes an ellipse having an extremely long major axis. The filler supply device 3 is configured to supply the filler wire 7 from the longitudinal axis direction of the cross section of the laser beam 5.

The laser welding irradiator of the fifth embodiment is formed in a shape that is long in the longitudinal axis direction of the cross section of the laser beam 5 and narrow in the direction perpendicular thereto. When a laser welding irradiator is inserted into a narrow narrow groove and welded while moving along the groove, the portion extending in the long axis direction of the laser beam 5 is melted by the laser beam 5 into the pre-heated base metal portion. Since the applied filler wire 7 hits, the familiarity of the consumable material 44 to be laminated with the base material 4 is improved, and the quality of welding is improved.

[0043]

Embodiment 6 FIG. 8 is a partial sectional view showing a sixth embodiment of the laser welding irradiator of the present invention. The laser welding irradiator of the sixth embodiment differs from that of the first embodiment in that the sheath 2 itself is formed of a consumable member. The irradiator for laser welding according to the present embodiment has a mechanism 26 for pushing out the sheath 2, so that the sheath 2 itself is melted by the laser light 5 emitted from the optical fiber 1 and fused with the target base material 4. It was done. A jig 28 having a hole 24 through which the protective gas 6 flows with little friction with the sheath 2 is attached to the tip of the optical fiber 1 so that the optical fiber 1 is held at the center axis position of the sheath 2. It has become.

In welding, the sheath 2 is pushed out by the pushing mechanism 26 as it is consumed, and when it is completely consumed, a new sheath 2 is set from the tip side of the laser welding irradiator to continue welding. The sheath 2 can be formed of the same material as the welding base material 4. In the laser welding irradiator thus configured, since the sheath 2 forms a consumable member, the size of the head is further reduced, and welding can be performed by inserting the head into an extremely narrow portion.

[0045]

Seventh Embodiment FIG. 9 is a perspective view showing a seventh embodiment of the laser welding irradiator according to the present invention. The laser welding irradiator of the seventh embodiment further includes a gas nozzle 16 for blowing a protective gas from the lateral direction between the tip of the sheath 2 and the tip of the filler wire 7 shown in each of the above embodiments. The gas nozzle 16 and the filler supply device 3 are arranged in a line. The housing 18 fixes these positional relationships and relays the laser light, auxiliary gas, or filler wire supplied from a welding apparatus main body (not shown) to the welding portion.

In the laser welding irradiator configured as described above, the auxiliary gas ejected from the gas nozzle 16 reliably blows off the plasma generated between the tip of the sheath 2 and the filler wire 7 from the vertical direction. To prevent the end surface of the optical fiber 1 and the surface of the optical system such as the lens 10 from being contaminated by scattering particles. Also, each of the components is extremely thin,
Since these are arranged in a line, the welding base material 4 can be welded by inserting the tip into the narrow groove 42.

[0047]

[Embodiment 8] FIG. 10 is a partial sectional view showing an eighth embodiment of the laser welding irradiator of the present invention. The laser welding irradiator of the eighth embodiment has a second optical fiber 11 in addition to the first optical fiber 1 for guiding the laser light, and transmits an optical signal with the tip of the monitoring optical fiber 81 directed to the welding portion. And an optical fiber monitoring device 8 that can be displayed on a monitor at a remote location. In the figure, reference numeral 61 denotes an auxiliary gas supply pipe. The auxiliary gas is distributed to the sheath 2 of the first optical fiber 1 and the sheath 21 of the second optical fiber 11 in the housing 18.

The surface of the base metal 4 to be welded is preheated by using the laser light 51 irradiated from the second optical fiber 11 to melt the base material lightly in advance, thereby improving the surface wettability. (1) The filler wire 7 is melted using the laser beam 5 emitted from the optical fiber 1 and filled in the welded portion. Therefore, the molten filler metal fits well into the surface of the material, and forms a good weld having no unmelted portion with the base material. In addition, the welding portion being welded can be monitored by a remote monitor, and the welding position can be grasped by confirming the target position and observing the state of melting and light emission. If the above elements are arranged in a line and incorporated into the housing 18, it is not necessary to increase the width of the irradiator, and welding within a narrow groove is possible.

In the laser welding irradiator of the present invention, the base material of the optical fiber can be quartz. Since quartz transmits iodine laser light with a wavelength of 1.315 μm well, the laser welding irradiator using quartz as the base material of the optical fiber uses a high-output iodine laser to generate powerful energy. Head. Furthermore, since the iodine laser can be transmitted over long distances using a quartz optical fiber, a large iodine laser generator is installed at one corner of the processing plant, and an optical fiber network starting from this is set up inside the factory, A system for distributing laser energy to the laser welding irradiator of the present invention provided at each welding position via a distributor can be provided. In such a system, laser welding using high-power laser energy can be performed at various points in a factory.

Further, the laser welding irradiator of the present invention is mounted on a moving mechanism and performs a welding operation while moving automatically or by remote control. The moving mechanism includes a rotary jig that rotates in all the postures, and the laser welding irradiator is mounted on the rotary jig. Since laser light irradiation is possible in all directions with such a moving mechanism, it is possible to lay pipelines and weld in narrow places,
In addition, large structures and thick plates can be welded.

[0051]

As described above, since the laser welding irradiator of the present invention is made extremely thin using a part slightly thicker than a thin optical fiber, it can be inserted into a narrow groove to perform laser welding. it can. Further, since the auxiliary gas for laser welding is transported along the optical fiber, the optical fiber is not overheated and damaged even if the laser welding irradiator is arranged near the welded portion. Since the laser welding irradiator of the present invention can perform welding work in all postures, it can be used to lay a pipeline or construct a large structure.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view showing a use state of a first embodiment of the present invention. FIG. 1A is a front view, and FIG. 1B is a side view.

FIG. 2 is a partial cross-sectional view showing a second embodiment of the present invention.

FIG. 3 is a partial sectional view showing a third embodiment of the present invention.

FIG. 4 is a sectional view taken along line IV-IV of FIG. 3;

FIG. 5 is a partial sectional view showing a fourth embodiment of the present invention.

FIG. 6 is a partial sectional view showing a fifth embodiment of the present invention.

FIG. 7 is a view taken along the line VII-VII in FIG. 6;

FIG. 8 is a partial sectional view showing a sixth embodiment of the present invention.

FIG. 9 is a perspective view showing a seventh embodiment of the present invention.

FIG. 10 is a partial sectional view showing an eighth embodiment of the present invention.

FIG. 11 is a view showing an example of use of a conventional laser welding head.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Optical fiber 2 Sheath body 3 Filler feeding device 4 Welding base material 5 Laser light 6 Protective gas 7 Filler wire 10 Microlens 44 Laminated welding layer

Claims (11)

[Claims] 1. An optical fiber for guiding a laser beam, a sheath for accommodating the optical fiber, and a filler supply mechanism are provided, and an auxiliary gas is ejected through a hole formed along the optical fiber between the sheath and the optical fiber. At the same time, the irradiator for laser welding is configured so that the filler supply mechanism feeds the filler wire into the light flux of the laser emitted from the optical fiber. 2. The irradiator for laser welding according to claim 1, wherein a tip of the sheath body projects from a tip of the optical fiber, and a part of laser light emitted from the optical fiber is a tip portion of the sheath body. A laser welding irradiator that is reflected by the inner wall of the laser and focused so that the energy of the laser light reaches far. 3. The laser welding irradiator according to claim 1, further comprising a microlens having a short focal length at a tip portion of the optical fiber, the sheath also covering the microlens, and the filler. An irradiator for laser welding, wherein a supply mechanism supplies the tip of the filler wire into the laser light flux condensed by the microlens. 4. The laser welding irradiator according to claim 3, wherein a gradient index lens is used in place of the microlens. 5. The laser welding irradiator according to claim 3, wherein a cylindrical lens arranged so that its central axis is orthogonal to the laser optical axis is used instead of the microlens, and is converted into a linear shape by the cylindrical lens. An irradiator for laser welding, characterized in that a filler wire is supplied in the axial direction of the laser beam. 6. The irradiator for laser welding according to claim 1, further comprising a gas nozzle for spraying a protective gas laterally between the tip of the filler wire and the tip of the sheath body. A laser welding irradiator configured such that the sheath body, the gas nozzle, and the filler wire are arranged in a line. 7. The irradiator for laser welding according to claim 1, further comprising a mechanism for pushing out the sheath body, the sheath body being melted and welded by laser light emitted from the optical fiber. Laser welding irradiator designed to be fused with the target base material. 8. The laser welding irradiator according to claim 1, further comprising at least one second optical fiber for guiding laser light, and the laser light is irradiated from the second optical fiber. A laser welding irradiator that preheats the material surface of the welded portion with laser light and melts the filler wire with the laser light emitted from the first optical fiber to fill the welded portion. 9. The laser welding irradiator according to any one of claims 1 to 8, further comprising a monitoring optical fiber having a fiber tip directed to a welded portion. . 10. A rotary jig that rotates in all orientations is provided, and the laser welding irradiator according to claim 1 is mounted on the rotary jig to enable irradiation of laser light in all directions. Moving mechanism. 11. The laser welding irradiator according to claim 1, wherein a base material of the optical fiber is quartz, and the laser light generated by an iodine laser is used. An irradiator for laser welding, which is characterized in that