JP2013154365A - Welding apparatus and welding method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a welding apparatus which can efficiently and readily weld a material to be welded having a gap in a butt joint thereof and difficult to move as appropriate, and to provide a welding method.SOLUTION: A welding apparatus 1 includes: an oscillator 2 for generating laser light; a laser head 3 having an optical waveguide for guiding the laser light and capable of radiating the laser light to a butt joint surface of a plurality of materials B to be welded; a laser displacement gauge 5 for measuring surface profiles of the materials B to be welded; a laser head supporting device 6 that supports the laser head 3 and can change a relative direction between the materials B to be welded and the laser head 3 based on a measurement result of the laser displacement gauge 5 so that the laser light is radiated in a direction along the butt joint surface of the materials B to be welded; a camera 7 for capturing an image of a gap in the butt joint surface; and an arithmetic device 11 that obtains a size of the gap in the butt joint surface from the image captured by the camera 7 to determine a control rate of the laser head 3 and allows the laser light to be radiated to both material sides of the materials B to be welded.

Description

  Embodiments according to the present invention relate to a welding apparatus and a welding method.

  Butt welding is known in which a plurality of materials to be welded are butted in substantially the same plane to form a butt joint, and this butt joint is welded. In laser welding, where the welded material is welded by irradiating the butt joint with laser light, if there is a gap between the welded materials, the welding speed is an appropriate value (the welding speed when the welded material comes in contact with almost no gap). It can be welded satisfactorily without defects such as dents or dents in the welded part. As an example, when butt welding a mild steel with a plate thickness of 1 mm with a laser beam, a welded material having a gap of about 0.05 mm can be favorably welded when the laser output is 3 kw and the welding speed is 4 m / min, It is known that materials to be welded with a gap of about 0.1 mm can be favorably welded by reducing the welding speed to 3 m / min (for example, see Non-Patent Document 1).

  In addition, a method of adding a filler material during welding to fill a gap between materials to be welded is also known. Such a method includes, for example, laser-arc hybrid welding using both laser welding and arc welding.

  Incidentally, a copying apparatus for butt welding including a CCD camera is known. This copying apparatus is configured to search for a groove line of a material to be welded from an image photographed by a CCD camera and to copy the welding torch to the groove line based on the search result (for example, Patent Document 1). reference.).

  Further, there is known a welding apparatus that moves a workpiece to be moved relative to the groove line direction, slides the butted portion, and reduces the gap between the workpieces for welding (see, for example, Patent Document 2). .

Japanese Patent Publication No. 5-70553 JP 2007-105775 A

  Welding at a welding speed lower than the proper value takes longer time to weld the same length, and loses the advantages of laser welding in terms of efficiency. In addition, lowering the welding speed below an appropriate value may cause an increase in penetration depth due to an increase in heat input, deformation of a material to be welded, expansion of a heat affected zone, and a decrease in toughness. Moreover, the size of the gap that can be dealt with by lowering the welding speed below the appropriate value is at most about 0.2 mm, and the laser beam passes through a gap larger than this, and this method cannot be applied.

  In addition, filling the gap between the welded materials by adding a filler material during welding, it is necessary to melt the filler material, so it takes longer time to weld the same length, Lose the advantages of laser welding in terms of efficiency. Moreover, laser-arc hybrid welding is complicated by using a heat source (arc) other than laser light, increasing heat input, concomitant increase in penetration depth, deformation of the work piece, and heat affected zone. There is a risk of enlarging and lowering toughness.

  By the way, since cans of structures such as containers and boilers use a lot of welding, it is desired to automate the welding and increase the production efficiency. However, in these structures, particularly large structures and inexpensive standard structures, the dimensional accuracy of each member corresponding to the material to be welded is low, and a large gap between the materials to be welded (for example, a gap exceeding 0.5 mm). ) May occur. In addition, in the welding operation of these structures, in addition to the mode in which the plate materials are butted against each other, a lid-like welded material is fitted into a box-shaped welded material that opens to one side (so-called inlay structure), and both welded materials are used. There is an aspect in which welding is integrated.

  In order to automate welding by applying a butt welding copying apparatus equipped with a CCD camera to a structure in which the gap between the welded materials tends to be large, the size of the gap between the welded materials becomes a problem. Even if the welding speed is lowered below an appropriate value, the size of the gap that can be handled is at most about 0.2 mm, and there is no change in the laser beam passing through a gap larger than this.

  In addition, a welding apparatus that moves a workpiece to be welded relative to each other and slides the butt portion to reduce the gap between the workpieces and welds the lid to the box-shaped workpiece. It is difficult to apply to an inlay structure in which a material is fitted and welded.

  Furthermore, consider the case of welding a large structure that is difficult to place on a surface plate. In this case, there are two methods for welding the entire structure: a method in which the welding apparatus or the welding location is fixed and the structure side is appropriately moved; and a structure in which the structure side is fixed and the welding device or the welding position is appropriately moved Can be taken.

  First, in the method of fixing the welding device or the welding location and moving the structure side appropriately, it is necessary to determine the position of the structure with respect to the laser beam irradiated by the welding device each time the device is moved. If it does so, the whole welding operation accompanied with the movement operation | work of a structure and a positioning operation | work will become complicated.

  On the other hand, the method of fixing the structure side and appropriately moving the welding apparatus or the welding location is convenient because the entire structure can be welded in stages. However, even in this case, when laser light is irradiated in the direction intersecting the butt joint surface, good penetration cannot be obtained in the joint.

  Then, an object of this invention is to provide the welding apparatus and welding method which can weld the to-be-welded material which has a clearance gap in a butt joint and cannot move appropriately | suitably efficiently and simply.

  In order to solve the above problems, a welding apparatus according to an embodiment of the present invention includes an oscillator that generates laser light and an optical waveguide that guides the laser light, and the laser light is applied to a butt joint surface of a plurality of materials to be welded. A laser head capable of irradiating a laser beam, a laser displacement meter for measuring the surface shape of the material to be welded, a direction for supporting the laser head and the laser beam along the joint surface based on the measurement result of the laser displacement meter A laser head support device capable of changing the relative orientation of the material to be welded and the laser head so as to irradiate the laser beam, a camera for photographing a gap between the joint surfaces, and a size of the gap from an image photographed by the camera. And an arithmetic unit that determines the control amount of the laser head and irradiates both the one side and the other side of the welded material with laser light. And wherein the door.

  In addition, a welding apparatus according to an embodiment of the present invention includes an oscillator that generates laser light, a laser head that has an optical waveguide that guides the laser light, and can irradiate the butt joint surface of the welded material with the laser light. A laser displacement meter for measuring the surface shape of the material to be welded, and the welding target so as to support the laser head and irradiate the laser light in a direction along the joining surface based on the measurement result of the laser displacement meter. And a laser head support device capable of changing the relative orientation of the material and the laser head.

  Furthermore, the welding method according to the embodiment of the present invention measures the surface shape of the workpiece, and the laser beam is irradiated in a direction along the butt joint surface of the workpiece based on the measurement result. The laser head is configured such that the relative direction between the welding material and the laser head is changed, the size of the gap between the joint surfaces is obtained, and the laser light is irradiated to both one side and the other side of the welding material. The control amount is determined, and the workpiece is welded.

  ADVANTAGE OF THE INVENTION According to this invention, the welding apparatus and welding method which can weld the to-be-welded material which has a clearance gap in a butt joint and cannot move appropriately | suitably efficiently and simply can be provided.

1 is a schematic system configuration diagram showing a welding apparatus according to a first embodiment of the present invention. Schematic which shows the control system of the welding apparatus which concerns on 1st Embodiment of this invention. The perspective view which shows the to-be-welded material which applies the welding apparatus and welding method which concern on 1st Embodiment of this invention. The perspective view which shows the to-be-welded material which applies the welding apparatus and welding method which concern on 1st Embodiment of this invention. The top view which shows the to-be-welded material to which the welding apparatus and welding method which concern on 1st Embodiment of this invention are applied. The top view which shows the to-be-welded material to which the welding apparatus and welding method which concern on 1st Embodiment of this invention are applied. Sectional drawing which shows a junction part in the case of welding in the state where the irradiation direction of a laser beam is not along the butt | joint joint surface of the to-be-welded material B. The perspective view which shows the arrangement | positioning relationship between the welding apparatus which concerns on 1st Embodiment of this invention, and a to-be-welded material. The side view which shows the mode of the measurement of the to-be-welded material with the laser displacement meter of the welding apparatus which concerns on 1st Embodiment of this invention. Sectional drawing which shows the to-be-welded material integrated by applying the conventional welding apparatus and the welding method. Sectional drawing which shows the to-be-welded material integrated by applying the conventional welding apparatus and the welding method. Schematic which shows the aspect in which the welding apparatus and welding method which concern on 1st Embodiment of this invention connect the spot diameter of a laser beam to the one side and other side of a to-be-welded material. The schematic system block diagram which shows the welding apparatus which concerns on 2nd Embodiment of this invention. Schematic which shows the control system of the welding apparatus which concerns on 2nd Embodiment of this invention. Schematic which shows the laser head of the welding apparatus which concerns on 2nd Embodiment of this invention. The schematic system block diagram which shows the welding apparatus which concerns on 3rd Embodiment of this invention. Schematic which shows the laser head of the welding apparatus which concerns on 3rd Embodiment of this invention. The schematic system block diagram which shows the welding apparatus which concerns on 4th Embodiment of this invention. Schematic which shows the laser head of the welding apparatus which concerns on 4th Embodiment of this invention.

  An embodiment of a welding apparatus and a welding method according to the present invention will be described with reference to the drawings.

[First Embodiment]
1st Embodiment of the welding apparatus which concerns on this invention is described with reference to FIGS.

  FIG. 1 is a schematic system configuration diagram showing a welding apparatus according to a first embodiment of the present invention.

  As shown in FIG. 1, a welding apparatus 1 according to this embodiment includes an oscillator 2 that generates laser light and an optical waveguide that guides the laser light, and emits laser light to a butt joint surface of a plurality of materials to be welded B. Irradiable laser head 3, laser displacement meter 5 for measuring the surface shape of the material B to be welded, and a direction in which the laser beam follows the butt joint surface based on the measurement result of the laser displacement meter 5 while supporting the laser head 3 A laser head support device 6 capable of changing the relative orientation of the workpiece B and the laser head 3 so as to irradiate the laser beam, a camera 7 for photographing the gap between the butt joint surfaces, and a butt joint from an image photographed by the camera 7 The size of the gap between the surfaces is obtained, the control amount of the laser head 3 is determined, and laser light is irradiated to both one side (the material to be welded B1) and the other side (the material to be welded B2) of the material to be welded B. It includes a calculation device 11, the.

  Further, the welding device 1 includes a laser control device 12 that controls the operation of the oscillator 2, a laser displacement meter control device 13 as an interface that acquires measurement results from the laser displacement meter 5 and transmits the measurement results to the arithmetic device 11, and an image from the camera 7. And an image acquisition device 14 serving as an interface for acquiring the information and transmitting it to the arithmetic device 11, and a robot control device 15 for controlling the operation of the laser head support device 6.

  The optical fiber 16 guides laser light from the oscillator 2 to the laser head 3.

  The laser head support device 6 operates based on the control of the robot control device 15. The laser head support device 6 is a robot arm having multi-axis joints, and supports the laser head 3, the laser displacement meter 5 and the camera 7 in the vicinity of the material to be welded B, and the perspective direction with respect to the material to be welded B and the perspective direction. In a direction that intersects (referred to as “translation direction”). The laser head support device 6 moves the laser head 3 along the butt joint surface of the material to be welded B within the movable range by making full use of multi-axis joints. The laser head support device 6 includes a sensor group 17 that measures displacement and the like in order to specify the position coordinates of the laser head 3, the laser displacement meter 5, and the camera 7. The sensor group 17 is a displacement meter such as a potentiometer.

  The laser head support device 6 has a joint that changes the direction of the laser head 3, that is, the irradiation direction of the laser light. This joint allows the laser head 3 to swing, so-called swinging motion. The oscillation of the laser head 3 changes the direction of the laser beam with respect to the workpiece B.

  Further, the laser head support device 6 includes a driving device 18 that changes the direction of the laser head 3. The drive device 18 changes the direction of the laser head 3 in accordance with a command from the arithmetic device 11 via the robot control device 15. The orientation of the laser head 3 may be changed manually based on the measurement result of the laser displacement meter 5.

  Here, a material to be welded that needs to be welded beyond the movable range of the laser head 3 by the laser head support device 6 is called a large structure. When welding a large structure, the welding apparatus 1 appropriately moves at least the laser head support device 6, the laser head 3, the laser displacement meter 5, and the camera 7 to appropriately weld the welding portion of the entire large structure.

  The camera 7 is a CCD camera.

  The arithmetic unit 11 acquires an image photographed by the camera 7 and a laser beam adjusting unit 19 that determines a control amount of the laser head 3 in which the spot diameter of the laser beam to be welded B is larger than the gap between the butt joint surfaces. Then, a scanning line is searched from the brightness of this image, the position of the butt joint surface is obtained, and a scanning processing unit 21 for determining a control amount in the translation direction of the laser head 3 so that the laser beam follows the groove line, and a laser displacement And a swing processing unit 22 that obtains a total of 5 measurement results and determines a control amount in the swing direction of the laser head 3 so that the laser light follows the butt joint surface.

  The laser light adjusting unit 19 acquires an image taken by the camera 7, searches for a groove line from the brightness of the image, obtains the size of the gap of the butt joint surface, and determines the size of the welded material B from the size of the gap. Control amount determination for determining the control amount in the near and near direction of the laser head 3 so as to connect the required spot diameter calculation unit 23 for obtaining a required size of the spot diameter of the laser beam to be connected to the spot diameter required by the necessary spot diameter calculation unit 23 And a laser output adjustment unit 26 that increases the output of the oscillator 2 as the spot diameter obtained by the required spot diameter calculation unit 23 increases.

  The robot controller 15 sends the control amount in the translation direction, the control amount in the oscillation direction, and the control amount in the perspective direction of the laser head 3 from the arithmetic unit 11 in accordance with the start or stop of the operation of the oscillator 2 by the laser control device 12. Based on these control amounts, the respective joints of the laser head support device 6 are driven, and as a result, the laser head 3 is moved to weld the material B to be welded.

  In addition, the robot control device 15 acquires a measurement result from the sensor group 17 of the laser head support device 6 and stores it, a control amount in the translation direction of the laser head 3 from the arithmetic device 11, and a swing direction. And the control amount in the perspective direction are obtained, and these control amounts are compared with the measurement results of the sensor group 17 stored in the teaching data storage unit 27 to perform numerical control of the laser head support device 6. And comprising.

  FIG. 2 is a schematic diagram showing a control system of the welding apparatus according to the first embodiment of the present invention.

  As shown in FIG. 2, the calculation device 11 of the welding apparatus 1 according to the present embodiment includes a gap amount calculation function 31, a necessary spot diameter calculation function 32, a perspective position calculation function 33, a laser output calculation function 35, Laser head-to-be-welded material distance calculation function 36, laser head movement amount calculation function 37, joint surface inclination amount calculation function 38, laser head swing amount calculation function 39, laser head support device control amount calculation function 41, .

  The gap amount calculation function 31 obtains the groove line, and hence the size of the gap between the butt joint surfaces, from the brightness and darkness of the image taken by the camera 7. The necessary spot diameter calculation unit 23 includes a gap amount calculation function 31.

  The required spot diameter calculation function 32 calculates the required size of the spot diameter of the laser beam to be connected to the workpiece B from the size of the gap of the butt joint surface obtained by the gap amount calculation function 31. The required spot diameter calculation unit 23 includes a required spot diameter calculation function 32.

  The perspective position calculation function 33 calculates the position of the laser head 3 in the perspective direction for connecting the spot diameters required by the necessary spot diameter calculation function 32. The control amount determination unit 25 includes a perspective position calculation function 33.

  The laser output calculation function 35 obtains an appropriate laser output capable of efficiently proceeding welding at the spot diameter required by the required spot diameter calculation function 32, and determines the control amount of the oscillator 2 corresponding to this. The laser output adjustment unit 26 includes a laser output calculation function 35.

  The laser head-to-be-welded material distance calculation function 36 obtains a measurement result from the sensor group 17 of the laser head support device 6 and obtains a relative positional relationship between the to-be-welded material B and the laser head 3. The control amount determination unit 25 includes a laser head-to-be-welded material distance calculation function 36.

  The laser head movement amount calculation function 37 includes a position in the perspective direction of the laser head 3 obtained by the perspective position calculation function 33 and a relative relationship between the laser head 3 and the workpiece B to be welded obtained by the laser head-to-be-welded material distance calculation function 36. The amount of control of the laser head 3 in the perspective direction is determined from the specific positional relationship. The control amount determination unit 25 includes a laser head movement amount calculation function 37.

  The joint surface tilt amount calculation function 38 obtains the measurement result of the laser displacement meter 5 and determines how the workpiece B is tilted with reference to the laser head support device 6. The swing processing unit 22 includes a joint surface inclination amount calculation function 38.

  The laser head swing amount calculation function 39 determines a control amount in the swing direction of the laser head 3 in order to bring the laser light along the butt joint surface from the inclination of the workpiece B required by the joint surface tilt amount calculation function 38. The swing processing unit 22 includes a laser head swing amount calculation function 39.

  The laser head support device control amount calculation function 41 is a control amount in the swing direction of the laser head 3 acquired from the laser head swing amount calculation function 39 and a perspective direction of the laser head 3 acquired from the laser head movement amount calculation function 37. In addition to the control amount, a numerical value for driving each joint of the laser head support device 6 based on the control amount in the translation direction of the laser head 3 acquired from the copying processing unit 21 and the measurement result acquired from the teaching data storage unit 27 Take control. The robot control unit 28 includes a laser head support device control amount calculation function 41.

  The welding apparatus 1 can butt a plurality of, for example, two flat plates in substantially the same plane to form a butt joint, and of course can weld this butt joint. It is suitable for so-called can making, in which a lid-like workpiece is fitted (so-called inlay structure) and both workpieces are welded and integrated. Therefore, the material to be welded B to be manufactured will be described.

  3 and 4 are perspective views showing a material to be welded to which the welding apparatus and the welding method according to the first embodiment of the present invention are applied.

  5 and 6 are plan views showing a material to be welded to which the welding apparatus and the welding method according to the first embodiment of the present invention are applied.

  As shown in FIGS. 3 to 6, the welded material B to which the welding apparatus 1 and the welding method according to the present embodiment are applied includes a box-shaped welded material B1 that opens to one side and a lid-shaped welded material B2. And comprising. The welded material B1 includes a stepped portion b1 that supports the welded material B2 fitted into the opening edge.

  The shape of the butt joint between the material to be welded B1 and the material to be welded B2 is type I.

  When the work piece B2 is fitted into the stepped portion b1 of the work piece B1, the butt joint between the edge of the work piece B2 and the opening of the work piece B1, that is, the work piece B2 and the work piece B1. A gap G is generated on the surface. The gap G is generated because the dimensional accuracy of the workpieces B1 and B2 is not sufficiently high. However, if the accuracy is too high, it is difficult to fit the workpiece B2 into the workpiece B1. It is not preferable because the welding materials B1 and B2 are expensive.

  Moreover, when the to-be-welded material B is a large-sized structure, the welding apparatus 1 and the welding method weld and integrate the to-be-welded material B while changing the relative position with respect to the to-be-welded material B to be fixed. (FIG. 6).

  In this way, by moving the welding location to which the welding apparatus 1 and the welding method are applied instead of the material to be welded B, the number of operations related to the placement of the material to be welded B is suppressed, and the material to be welded B is substantially reduced. After the placement, the entire workpiece B can be welded without being moved.

  By the way, if the welding location to which the welding apparatus 1 and the welding method are applied is moved, the irradiation direction of the laser beam may not be located in the butt joint surface of the material to be welded B.

  FIG. 7 is a cross-sectional view showing a joint portion when welding is performed in a state where the irradiation direction of the laser beam is not along the butt joint surface of the material B to be welded. FIG. 7 shows a portion without a gap G for the sake of simplicity.

  As shown in FIG. 7, if the irradiation direction L of the laser beam is no longer located in the butt joint surface P of the workpiece B as the welding location to which the welding apparatus 1 and the welding method are applied, The penetration W is inclined with respect to the butt joint surface P, and an unmelted region Z is generated, so that a good joint cannot be obtained.

  Therefore, the welding apparatus 1 uses the laser displacement meter 5 to clarify the shape of the material to be welded B, and hence the direction of the butt joint surface, and by oscillating the laser head 3, the laser light irradiation direction is applied to the butt joint surface. Make it.

  FIG. 8 is a perspective view showing the positional relationship between the welding apparatus and the material to be welded according to the first embodiment of the present invention.

  FIG. 9 is a side view showing a state of measurement of the material to be welded by the laser displacement meter of the welding apparatus according to the first embodiment of the present invention.

  As shown in FIGS. 8 and 9, the swing processing unit 22 of the welding apparatus 1 measures the surface shape of the material to be welded B with the laser displacement meter 5, and the positional relationship between the surface shape and the welding surface (generally, The direction of the butt joint surface is specified from (perpendicular to), and the laser head 3 is swung so that the laser beam irradiation direction is aligned with the butt joint surface.

  The angle θ formed between the laser beam irradiation direction and the butt joint surface is determined by the distances a, b, c, d between the laser displacement meters 5a, 5b, 5c, 5d arranged at four locations and the material B to be welded. From the distance e in the translation direction for each measurement point, the following equation is used.

θ = tan ⁻¹ {(ba) ÷ e}
By the way, when a conventional welding apparatus or welding method is applied to the material to be welded B, the lid-shaped material to be welded B2 may be deformed by a thermal effect or the gap G may be enlarged.

  10 and 11 are cross-sectional views showing a material to be welded integrated by applying a conventional welding apparatus or welding method.

  As shown in FIG. 10, welding the workpiece B with the gap G by lowering the welding speed from an appropriate value increases the heat input to the welded portion, compared to the plate thickness of the workpiece B2. There is a possibility that the heat-affected zone becomes large, and the lid-like welded material B2 is expanded by heat, and the welded material B2 is deformed when the welded portion W is cooled and solidified.

  Moreover, as shown in FIG. 11, the conventional welding apparatus or welding method welds one edge even if the gap G of each edge of the workpiece B2 is weldable before welding. Then, the gap G is concentrated on the other edge, and the size of the gap may exceed the size that can be welded.

  Further, in the conventional welding apparatus or welding method, if the size of the gap between the butt joint surfaces approaches the spot diameter of the laser beam or becomes larger than the spot diameter, the laser beam passes through the gap and cannot be welded.

  Therefore, in the welding apparatus 1 and the welding method according to the present embodiment, the control amount of the laser head 3 is determined according to the size of the gap between the butt joint surfaces, and one side of the welding material B (the welding material B1) and Both sides of the other side (the material to be welded B2) are irradiated with laser light. More specifically, the welding apparatus 1 and the welding method according to the present embodiment prevent the laser light from passing through the gap of the butt joint surface by adjusting the control amount of the laser head 3, particularly the control amount in the perspective direction, The laser head 3 is controlled so that the spot diameter extends over both the workpieces B1 and B2.

  FIG. 12 is a schematic view showing an aspect in which the welding apparatus and the welding method according to the first embodiment of the present invention connect the spot diameter of laser light to one side and the other side of the workpiece.

  As shown in FIG. 12, the condenser lens 42 of the laser head 3 according to the present embodiment focuses the focal point f at the position of the focal length La. Accordingly, the welding apparatus 1 moves the separation distance Lb between the laser head 3 and the workpiece B or the separation distance Lb between the condenser lens 42 and the workpiece B closer to the condenser lens 42 side than the focal point f. The hole shape is enlarged, and the spot diameter W0 of the laser beam to be connected to the workpiece B is increased. At this time, the welding apparatus 1 brings the condensing lens 42 close to the material to be welded B so that the spot diameter W0 is larger than the size of the gap G, melts the joint portions of the materials to be welded B1 and B2, and the gap G And welding the material B to be welded. The separation distance Lb is determined by a control amount in the perspective direction of the laser head 3 and may be controlled by moving the entire laser head 3 or may be controlled by moving only the condenser lens 42.

  At this time, the butt joint surface of the material to be welded B deviates from the focal point f, that is, defocuses, the energy density of the laser beam at the butt joint surface decreases, and in some cases, welding becomes difficult. Increase the laser power appropriately.

  Further, the relationship between the size of the gap G between the butt joint surfaces and the required size of the spot diameter of the laser beam to be welded B can be obtained by organizing data collected experimentally in advance prior to welding. Specifically, the welding apparatus 1 is made of SUS304 (austenitic stainless steel) having a gap G by proportionally increasing the spot diameter from about 0.6 mm to about 1.2 mm with respect to the gap G of about 0.2 mm. The welding material B is welded. Further, by setting the spot diameter to about 1.2 mm, the welding speed to about 0.75 m / min, the laser output to about 3 kW, and the heat input to about 2400 J / cm, the welding apparatus 1 has a gap G of about 0.6 mm. SUS316L (austenitic stainless steel) to be welded B having a thickness of 8 mm can be welded. Furthermore, by setting the spot diameter to about 0.6 mm, the welding speed to about 2 m / min, the laser output to about 1 kW, and the heat input to about 3000 J / cm, the welding apparatus 1 has a gap G of about 0.2 mm. It is also possible to weld the material B to be welded of SUS304 (austenitic stainless steel).

  Further, the relationship between the size of the spot diameter of the laser beam connected to the material to be welded B and the laser output capable of performing welding efficiently is obtained by organizing data collected experimentally in advance prior to welding.

  The welding apparatus 1 applies substantially the same welding conditions to a material to be welded B made of SUS304, SUS316L other austenitic stainless steel, carbon steel, or Inconel (registered trademark, nickel-base superalloy). Can be welded. On the other hand, it is necessary for the welding apparatus 1 to greatly increase the heat input condition for a material having a high laser beam reflectance such as an aluminum alloy or copper.

  And the welding method which concerns on this embodiment measures the surface shape of the to-be-welded material B, and based on the result of this measurement, the to-be-welded material is irradiated in the direction along the butt joint surface of the to-be-welded material B The relative direction between B and the laser head 3 is changed, the size of the gap between the butt joint surfaces is obtained, and both one side (the material to be welded B1) and the other side (the material to be welded B2) of the material to be welded B The control amount of the laser head 3 is determined so that the laser beam is irradiated, and the workpiece B is welded.

  Further, in the welding method according to the present embodiment, the control amount of the laser head 3 is determined such that the spot diameter of the laser beam to be connected to the workpiece B is larger than the gap between the butt joint surfaces.

  Furthermore, the welding method according to the present embodiment increases the output of the oscillator 2 that generates laser light as the spot diameter of the laser light increases.

  In the welding apparatus 1 and the welding method according to the present embodiment, the workpiece B is measured by the laser displacement meter 5, the inclination of the butt joint surface with respect to the laser beam irradiation direction is clarified, and the laser beam irradiation direction is the butt joint. The laser head 3 is swung along the surface to adjust the irradiation direction of the laser beam. Thereby, the welding apparatus 1 and the welding method can weld the to-be-welded material B satisfactorily, without irradiating a laser beam to a butt | joining joint surface reliably and producing a dent and a drop in a welding part. In addition, when there is a gap in the butt joint surface, it is possible to evenly melt one side (the material to be welded B1) and the other side (the material to be welded B2) of the material to be welded B that separate the gap. The material to be welded B can be welded satisfactorily. Such improvement of the gap tolerance by the welding apparatus 1 and the welding method is particularly effective in the welding of structures where it is difficult to sufficiently increase the dimensional accuracy between the materials to be welded B1 and B2, such as cans. It does not cause sagging and secures the necessary amount of penetration to significantly improve the quality of welding. Furthermore, this is particularly beneficial when the workpiece B is a large structure. That is, the welding apparatus 1 and the welding method facilitate welding of the entire welded material B by sequentially moving the place where the welding apparatus 1 is used or the place where the welding method is applied without moving the welded material B. . Moreover, a large structure requires a greater penetration depth in the welded portion than a medium or small structure. If the laser light is irradiated non-parallel to the butt joint surface, the penetration depth becomes insufficient and the joint portion remains undissolved. On the other hand, in the welding apparatus 1 and the welding method, the laser head 3 is swung and the irradiation direction of the laser beam is adjusted, whereby the laser beam is irradiated into the butt joint surface to obtain a good weld with no unmelted residue.

[Second Embodiment]
A second embodiment of the welding apparatus and the welding method according to the present invention will be described with reference to FIGS.

  FIG. 13 is a schematic system configuration diagram showing a welding apparatus according to the second embodiment of the present invention.

  In addition, in 1 A of welding apparatuses which concern on this embodiment, the same code | symbol is attached | subjected to the same structure as the welding apparatus 1 of 1st Embodiment, and the overlapping description is abbreviate | omitted.

  As shown in FIG. 13, the arithmetic unit 11A of the welding apparatus 1A according to the present embodiment has a control amount of the laser head 3A so that the spot diameter of the laser beam to be welded B reciprocates across the gap of the butt joint surface. To decide.

  The arithmetic unit 11A replaces the laser beam adjustment unit 19 and adjusts the amount of reciprocation that determines the control amount of the laser head 3A so that the spot diameter of the laser beam to be welded B reciprocates across the gap between the butt joint surfaces. The unit 45 is provided.

  The reciprocating amount adjustment unit 45 acquires an image taken by the camera 7, searches for a groove line from the brightness of the image, obtains the size of the gap of the butt joint surface, and determines the size of the welded material B from the size of the gap. The required reciprocating amount and period of the spot diameter of the laser beam to be connected to is obtained.

  FIG. 14 is a schematic diagram showing a control system for a welding apparatus according to the second embodiment of the present invention.

  As shown in FIG. 14, the calculation device 11A of the welding apparatus 1A according to the present embodiment replaces the necessary spot diameter calculation function 32 and the perspective position calculation function 33 of the calculation device 11A with a required reciprocation amount calculation function 46 and a reciprocation. A moving range calculation function 47.

  The required reciprocating amount calculating function 46 calculates the required reciprocating amount and the period of the spot diameter of the laser beam to be welded B from the size of the gap of the butt joint surface obtained by the gap amount calculating function 31. The reciprocating amount adjusting unit 45 includes a necessary reciprocating amount calculating function 46.

  The reciprocation range calculation function 47 obtains a control amount of the laser head 3A for reciprocating the spot diameter obtained by the required reciprocation amount calculation function 46. The reciprocation amount adjustment unit 45 includes a reciprocation range calculation function 47.

  The laser output calculation function 35A calculates an appropriate laser output capable of proceeding with welding efficiently at the spot diameter required by the required reciprocation amount calculation function 46, and determines the control amount of the oscillator 2 corresponding to this. The laser output adjustment unit 26 includes a laser output calculation function 35A.

  The laser head-to-be-welded material distance calculation function 36A obtains a measurement result from the sensor group 17 of the laser head support device 6 and obtains a relative positional relationship between the to-be-welded material B and the laser head 3A. The reciprocation amount adjustment unit 45 includes a laser head-to-be-welded material distance calculation function 36A.

  The laser head movement amount calculation function 37A includes the reciprocation amount and period of the laser head 3A required by the reciprocation range calculation function 47, the welding material B and the laser head 3A required by the laser head-to-be-welded material distance calculation function 36A. The control amount of the laser head 3 </ b> A is determined from the relative positional relationship. The reciprocation amount adjustment unit 45 includes a laser head movement amount calculation function 37A.

  FIG. 15 is a schematic view showing a laser head of a welding apparatus according to the second embodiment of the present invention.

  As shown in FIG. 15, the laser head 3 </ b> A of the welding apparatus 1 </ b> A according to the present embodiment further changes the traveling direction of the laser light whose traveling direction is changed by the folding mirror 51 and the folding mirror 51 that changes the traveling direction of the laser light. The mirror 52, the condensing lens 42 which condenses the laser beam which changed the advancing direction with the mirror 52, and the electric motor 53 which reciprocates the folding mirror 51 are provided. The laser head 3A operates the electric motor 53 according to the control amount output from the arithmetic unit 11A, and moves the folding mirror 51 with an appropriate amount of reciprocation and a reciprocation period to reciprocate the laser light.

  In the welding apparatus 1A and the welding method according to the present embodiment, the control amount of the laser head 3A is determined according to the size of the gap between the butt joint surfaces, and one side (the material to be welded B1) and the other side of the material to be welded B are determined. Both (welded material B2,) are irradiated with laser light. More specifically, the welding apparatus 1A and the welding method according to the present embodiment adjust the control amount of the laser head 3A, particularly the reciprocating amount of the folding mirror 51 and the period thereof, so as to cross the gap of the butt joint surface. Are reciprocated to irradiate laser beams so that the spot diameter extends over both of the workpieces B1 and B2 (laser beams indicated by solid lines and broken lines in FIG. 15).

  The laser light emitted by the laser head 3A according to the present embodiment straddles the butt joint surface of the material to be welded B and passes through one side (the material to be welded B1) and the other side (the material to be welded B2). Go back and forth and reciprocate. At this time, the welding apparatus 1A melts the joint portions of the materials to be welded B1 and B2 and fills the gaps even if the spot diameter of the laser beam connected to the material to be welded B is not larger than the gap between the butt joint surfaces. The workpiece B is welded.

  Further, the relationship between the size of the gap G between the butt joint surfaces, the amount of reciprocation of the spot diameter of the laser beam to be welded B, and the period thereof is obtained by organizing data collected experimentally in advance prior to welding. Specifically, the spot diameter is about 0.4 mm, the amount of reciprocation of the laser beam is about 1.25 mm, the period of reciprocation is about 100 Hz, the welding speed is about 1.5 m / min, the laser output is about 2 kW, the heat input Is set to about 800 J / cm, the welding apparatus 1A can weld the workpiece B of SUS316L (austenitic stainless steel) having a thickness G of about 8 mm with a gap G of about 0.6 mm.

  And the welding method which concerns on this embodiment determines the control amount of 3 A of laser heads so that the spot diameter of the laser beam tied to the to-be-welded material B may reciprocate across the gap | interval of a butt joint surface.

  The welding apparatus 1A and the welding method according to the present embodiment measure the workpiece B with the laser displacement meter 5, clarify the inclination of the butt joint surface with respect to the laser beam irradiation direction, and the laser beam irradiation direction is the butt joint. The laser head 3A is swung along the surface to adjust the irradiation direction of the laser beam. As a result, the welding apparatus 1A and the welding method can reliably weld the welded material B without irradiating the butt joint surface with laser light and causing a dent or drop in the welded portion. In addition, when there is a gap in the butt joint surface, it is possible to evenly melt one side (the material to be welded B1) and the other side (the material to be welded B2) of the material to be welded B that separates the gap. The material to be welded B can be welded satisfactorily. Such improvement of the gap margin by the welding apparatus 1A and the welding method is particularly effective in the welding of structures where it is difficult to sufficiently increase the dimensional accuracy between the workpieces B1 and B2, such as cans. No sagging occurs, ensuring the necessary amount of penetration and significantly improving welding quality. Furthermore, this is particularly beneficial when the workpiece B is a large structure. That is, the welding apparatus 1A and the welding method facilitate welding of the entire welded material B by sequentially moving the place where the welding apparatus 1A is used or the place where the welding method is applied without moving the welded material B. . Moreover, a large structure requires a greater penetration depth in the welded portion than a medium or small structure. If the laser light is irradiated non-parallel to the butt joint surface, the penetration depth becomes insufficient and the joint portion remains undissolved. On the other hand, the welding apparatus 1A and the welding method obtain good welding without melting by irradiating the laser beam into the butt joint surface by swinging the laser head 3A and adjusting the irradiation direction of the laser beam.

[Third Embodiment]
A third embodiment of the welding apparatus and the welding method according to the present invention will be described with reference to FIGS. 16 and 17.

  FIG. 16 is a schematic system configuration diagram showing a welding apparatus according to the third embodiment of the present invention.

  In addition, in the welding apparatus 1B according to the present embodiment, the same components as those of the welding apparatus 1 of the first embodiment and the welding apparatus 1A of the second embodiment are denoted by the same reference numerals, and redundant description is omitted.

  As shown in FIG. 16, the welding apparatus 1B according to the present embodiment does not necessarily require the laser light adjustment unit 19 of the welding apparatus 1 or the reciprocation amount adjustment unit 45 of the welding apparatus 1A (the calculation unit 11B without these adjustment units). And a laser head 3B having a plurality of optical waveguides instead of the laser head 3 of the welding apparatus 1 and the laser head 3A of the welding apparatus 1A.

  FIG. 17 is a schematic view showing a laser head of a welding apparatus according to the third embodiment of the present invention.

  As shown in FIG. 17, the laser head 3 </ b> B of the welding apparatus 1 </ b> B according to the present embodiment is capable of so-called twin spot laser welding, and includes a first optical waveguide 55 that divides and emits laser light, and a second optical waveguide. 56. Further, the laser head 3B includes a prism 57 that changes a part of the traveling direction of the laser light.

  The laser head 3 </ b> B changes the traveling direction of a part of the laser light incident on the condenser lens 42 with the prism 57. On the other hand, the remainder of the laser light enters the condenser lens 42 without changing the traveling direction. The path of the laser light that passes through the prism 57 and enters the condenser lens 42 is the first optical waveguide 55, and the path of the laser light that directly enters the condenser lens 42 is the second optical waveguide 56.

  The spot diameter of the laser beam (a part of the laser beam) that the first optical waveguide 55 irradiates to one side (the material to be welded B1) of the workpiece B and the second optical waveguide 56 is the other side (the workpiece to be welded). The spot diameter of the laser beam (of the remaining portion) irradiated to the material B2) is separated by substantially the same distance as the gap of the material B to be welded. The welding apparatus 1B melts the joint portion of the material to be welded B1 with the laser light irradiated from the first optical waveguide 55 to the material to be welded B1, and is welded with the laser light irradiated to the material to be welded B2 from the second optical waveguide 56. The joint part of the material B2 is melted, the gap B is filled, and the workpiece B is welded.

  The size of the spot diameter of the laser beam that the first optical waveguide 55 connects to the workpiece B, the size of the spot diameter of the laser beam that the second optical waveguide 56 connects to the workpiece B, and the welding can be performed efficiently. The relationship with possible welding conditions is obtained by organizing data collected experimentally in advance prior to welding. Specifically, the two spot diameters are about 0.6 mm, the distance between the two spot diameters is about 0.6 mm, the welding speed is about 0.75 m / min, the laser output is about 3 kW, and the heat input is about 2400 J / By setting it to cm, the welding apparatus 1B welds the material B to be welded of SUS316L (austenitic stainless steel) having a gap G of about 0.6 mm and a thickness of 8 mm.

  In the welding method according to the present embodiment, the laser beam is branched by the laser head 3B to irradiate a part of the laser beam to one side (the material to be welded B1) of the material to be welded B and the other of the materials to be welded B. The control amount of the laser head 3B is determined so that the other side of the laser beam is irradiated to the side (the material to be welded B2).

  In the welding apparatus 1B and the welding method according to the present embodiment, the workpiece B is measured by the laser displacement meter 5, the inclination of the butt joint surface with respect to the laser light irradiation direction is clarified, and the laser light irradiation direction is the butt joint. The laser head 3B is swung along the surface to adjust the irradiation direction of the laser light. Thereby, the welding apparatus 1B and the welding method can weld the welding material B satisfactorily without irradiating the butt joint surface with laser light without causing a dent or depression in the welded portion. In addition, when there is a gap in the butt joint surface, it is possible to evenly melt one side (the material to be welded B1) and the other side (the material to be welded B2) of the material to be welded B that separate the gap. The material to be welded B can be welded well. Such improvement of the gap tolerance by the welding apparatus 1B and the welding method is particularly effective in the welding of structures where it is difficult to sufficiently improve the dimensional accuracy between the workpieces B1 and B2, such as cans. It does not cause sagging and secures the necessary amount of penetration to significantly improve the quality of welding. Furthermore, this is particularly beneficial when the workpiece B is a large structure. That is, the welding apparatus 1B and the welding method facilitate welding of the entire welded material B by sequentially moving the place where the welding apparatus 1B is used or the place where the welding method is applied without moving the welded material B. . Moreover, a large structure requires a greater penetration depth in the welded portion than a medium or small structure. If the laser light is irradiated non-parallel to the butt joint surface, the penetration depth becomes insufficient and the joint portion remains undissolved. On the other hand, in the welding apparatus 1B and the welding method, the laser head 3B is swung and the irradiation direction of the laser beam is adjusted to irradiate the laser beam into the butt joint surface, thereby obtaining a good weld with no unmelted portion.

[Fourth Embodiment]
A fourth embodiment of a welding apparatus and a welding method according to the present invention will be described with reference to FIGS. 18 and 19.

  FIG. 18 is a schematic system configuration diagram showing a welding apparatus according to the fourth embodiment of the present invention.

  In addition, in 1C of welding apparatuses which concern on this embodiment, the same code | symbol is attached | subjected to the same structure as the welding apparatus 1 of 1st Embodiment, and the overlapping description is abbreviate | omitted.

  As shown in FIG. 18, a welding apparatus 1 </ b> C according to this embodiment includes a laser head 3 </ b> C having a plurality of optical waveguides instead of the laser head 3 of the welding apparatus 1.

  Note that the calculation device 11C of the welding apparatus 1C according to the present embodiment does not necessarily require the laser light adjustment unit 19 of the welding apparatus 1 or the reciprocation adjustment unit 45 of the welding apparatus 1A, similarly to the calculation device 11B of the welding apparatus 1B. .

  FIG. 19 is a schematic view showing a laser head of a welding apparatus according to the fourth embodiment of the present invention.

  As shown in FIG. 19, the laser head 3 </ b> C of the welding apparatus 1 </ b> C according to the present embodiment includes an optical waveguide 58 in which the spot diameter of the laser beam to be welded B is larger than the gap between the butt joint surfaces. The laser head 3 </ b> C includes a collimating lens 59 that optically adjusts the laser light emitted from the optical fiber 16 to be in a parallel state, and a condensing lens 61 that collects the laser light emitted from the collimating lens 59. An optical waveguide 58 is a path of laser light that passes from the optical fiber 16 through the collimator lens 59 and enters the condenser lens 61.

  That is, the welding apparatus 1 </ b> C, like the welding apparatus 1, sets the separation distance between the laser head 3 and the material to be welded B or the separation distance Lb between the condenser lens 42 and the material to be welded B rather than the focal point f. The keyhole shape is increased by adjusting the optical waveguide 58 instead of moving closer to the side, and the spot diameter of the laser beam connected to the workpiece B is expanded.

  The laser head 3 </ b> C adjusts the collimating lens 59 and the condensing lens 61 to change the spot diameter of the laser beam to be connected to the workpiece B.

  The spot diameter W0 is obtained by the following equation from the numerical aperture NA of the optical fiber 16, the focal length f1 of the condenser lens 61, the focal length f2 of the collimating lens 59, and the wavelength λ of the laser light.

W0 = (λ ÷ (2π × NA)) × (f1 ÷ f2)
And the welding method which concerns on this embodiment adjusts an optical waveguide so that the spot diameter of the laser beam tied to the to-be-welded material B may become larger than the clearance gap between butt | joining joint surfaces.

  The welding apparatus 1C and the welding method according to the present embodiment measure the workpiece B with the laser displacement meter 5, clarify the inclination of the butt joint surface with respect to the laser light irradiation direction, and the laser light irradiation direction is the butt joint. The laser head 3C is swung along the surface to adjust the irradiation direction of the laser beam. As a result, the welding apparatus 1C and the welding method can weld the workpiece B well without irradiating the butt joint surface with laser light without causing dents or depressions in the welded portion. In addition, when there is a gap in the butt joint surface, it is possible to evenly melt one side (the material to be welded B1) and the other side (the material to be welded B2) of the material to be welded B that separate the gap. The material to be welded B can be welded well. Such improvement of the gap tolerance by the welding apparatus 1C and the welding method is particularly effective in the welding of structures where it is difficult to sufficiently improve the dimensional accuracy between the workpieces B1 and B2, such as cans. It does not cause sagging and secures the necessary amount of penetration to significantly improve the quality of welding. Furthermore, this is particularly beneficial when the workpiece B is a large structure. That is, the welding apparatus 1C and the welding method facilitate welding of the entire welded material B by sequentially moving the place where the welding apparatus 1C is used or the place where the welding method is applied without moving the welded material B. . Moreover, a large structure requires a greater penetration depth in the welded portion than a medium or small structure. If the laser light is irradiated non-parallel to the butt joint surface, the penetration depth becomes insufficient and the joint portion remains undissolved. On the other hand, in the welding apparatus 1C and the welding method, the laser head 3C is swung and the irradiation direction of the laser beam is adjusted to irradiate the laser beam into the butt joint surface, thereby obtaining a good weld with no melt.

  Therefore, according to the welding apparatuses 1, 1 </ b> A, 1 </ b> B, 1 </ b> C and the welding method according to the present embodiment, it is possible to efficiently and easily weld the workpiece B having a gap in the butt joint and difficult to move appropriately.

  Note that the welding apparatuses 1, 1A, 1B, 1C and the welding method according to the present embodiment are applied to materials to be welded that have butt joints in close contact with each other or have small gaps that can be welded under general welding conditions and are easy to move. Of course it is also possible to do.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

1, 1A, 1B, 1C Welding device 2 Oscillator 3, 3A, 3B, 3C Laser head 5 Laser displacement meter 6 Laser head support device 7 Camera 11, 11A, 11B, 11C Arithmetic device 12 Laser control device 13 Laser displacement meter control device DESCRIPTION OF SYMBOLS 14 Image acquisition apparatus 15 Robot control apparatus 16 Optical fiber 17 Sensor group 18 Drive apparatus 19 Laser light adjustment part 21 Copying process part 22 Swing process part 23 Necessary spot diameter calculation part 25 Control amount determination part 26 Laser output adjustment part 27 Teaching data Storage unit 28 Robot control unit 31 Clearance amount calculation function 32 Required spot diameter calculation function 33 Perspective position calculation function 35, 35A Laser output calculation function 36, 36A Laser head-to-be-welded material distance calculation function 37, 37A Laser head movement amount calculation Function 38 Joint surface tilt amount calculation function 39 Laser Oscillation amount calculation function 41 Laser head support device control amount calculation function 42 Condensing lens 45 Reciprocation amount adjustment unit 46 Required reciprocation amount calculation function 47 Reciprocation range calculation function 48 Control amount determination unit 51 Folding mirror 52 Mirror 53 Electric motor 55 First Optical waveguide 56 Second optical waveguide 57 Prism 58 Optical waveguide 59 Collimating lens 61 Condensing lens

Claims (14)

An oscillator that generates laser light;
A laser head having an optical waveguide for guiding the laser beam and capable of irradiating the laser beam to a butt joint surface of a plurality of workpieces;
A laser displacement meter for measuring the surface shape of the material to be welded;
A laser capable of supporting the laser head and changing the relative orientation of the welded material and the laser head so that the laser beam is irradiated in a direction along the joining surface based on the measurement result of the laser displacement meter. A head support device;
A camera for photographing the gap between the joint surfaces;
An arithmetic unit that obtains the size of the gap from an image photographed by the camera, determines a control amount of the laser head, and irradiates both one side and the other side of the welded material with laser light; Welding device characterized by. The welding apparatus according to claim 1, wherein the laser head support device includes a drive device that changes a direction of the laser head. 3. The welding apparatus according to claim 1, wherein the arithmetic device determines the control amount at which a spot diameter of the laser beam connected to the workpiece is larger than the gap. The welding apparatus according to claim 3, wherein the arithmetic unit increases the output of the oscillator as the spot diameter increases. The said arithmetic unit determines the said control amount of the said laser head so that the spot diameter of the said laser beam tied to the said to-be-welded material may reciprocate across the said clearance gap. Welding equipment. The welding apparatus according to claim 1, wherein the laser head includes a first optical waveguide and a second optical waveguide that diverge and irradiate the laser light. The control device irradiates a first laser beam from the first optical waveguide to one side of the welding material and irradiates a second laser beam from the second optical waveguide to the other side of the welding material. The welding apparatus according to claim 6, wherein the quantity is determined. 3. The welding apparatus according to claim 1, wherein the laser head includes an optical waveguide in which a spot diameter of the laser beam connected to the workpiece is larger than the gap. An oscillator that generates laser light;
A laser head having an optical waveguide for guiding the laser beam and capable of irradiating the laser beam to the butt joint surface of the welded material;
A laser displacement meter for measuring the surface shape of the workpiece,
A laser capable of supporting the laser head and changing the relative orientation of the welded material and the laser head so that the laser beam is irradiated in a direction along the joining surface based on the measurement result of the laser displacement meter. A welding apparatus comprising: a head support device. Measure the surface shape of the material to be welded,
Based on the result of the measurement, the laser beam is irradiated in a direction along the butt joint surface of the workpiece, and the relative orientation of the workpiece and the laser head is changed,
Obtain the size of the gap between the joint surfaces,
Determine the control amount of the laser head so that the laser beam is applied to both the one side and the other side of the workpiece,
A welding method comprising welding the workpiece. The welding method according to claim 10, wherein the control amount is determined so that a spot diameter of the laser beam connected to the workpiece is larger than the gap. The welding method according to claim 11, wherein an output of an oscillator that generates the laser light is increased as the spot diameter increases. The welding method according to claim 10, wherein the control amount is determined so that a spot diameter of the laser beam connected to the workpiece to be reciprocated across the gap. The laser head is branched by the laser head to irradiate a part of the laser beam to one side of the welding material and determine the control amount to irradiate the other part of the laser beam to the other side of the welding material. The welding method according to claim 10.

Images