JP7105912B2 - LASER WELDING METHOD AND LAMINATED BODY - Google Patents

Description

The present invention relates to a laser welding method and laminate.

When welding a plurality of metal plates in a spot shape, laser spot welding using a laser welding apparatus is performed. In laser spot welding, a plurality of metal plates are welded by melting a plurality of metal plates with a laser beam and then cooling them (for example, Patent Document 1).

In Patent Document 1, the metal plate has a melting point or higher so that a first welding pattern capable of preheating the entire welding target is formed in a region inside the outer periphery of the welding target with a substantially circular outer shape in the metal plate. Weld by irradiating a laser beam with a high energy density, and then irradiate and weld the laser beam so as to form a second annular welding pattern along the outer periphery of the part to be welded, thereby forming a first welding pattern. The low-melting-point metal plating is evaporated during welding to increase the amount of molten metal during processing of the second welding pattern.

Japanese Patent Application Laid-Open No. 2009-148781 (Japanese Patent Application No. 2007-327220)

As in Patent Document 1, when the internal space is sealed by the weld, the air in the sealed space is heated during welding and expands to pressurize the weld and damage the weld. I can put it away. In addition, in Patent Document 1, an edge protruding upward was generated in the inner part of the welded portion, and the appearance and paintability of the laminated body after welding were poor, and the quality was low.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a laser welding method and a laminate that can prevent damage to the welded portion and improve the quality of the welded laminate. and

A laser welding method of the present invention is a laser welding method for irradiating a laser beam to join a laminate formed by stacking a plurality of metal plates, wherein the output of the laser beam is adjusted so that the laminate can be melted. a first step of irradiating along an outer peripheral path extending so as to surround a predetermined portion of the laminated body and having at least a portion thereof opened in the state of the laser beam; and a second step of irradiating along the inner peripheral portion of the outer peripheral path in a state in which the output is adjusted so as to melt without penetrating the metal plate of the uppermost layer of the laminate. and

According to the laser welding method of the present invention, the laser beam is directed so as to surround a predetermined portion of the laminate in a state in which the output is adjusted so that the laminate can be melted, and is directed to an outer peripheral path that is at least partially open. Since it has the first step of irradiating along the line, the air between the metal plates (gap) of the laminate can be discharged from the opened portion. As a result, inside the welded portion of the laminate, the air in the gap between the metal plates of the laminate does not thermally expand and damage the welded portion.

Further, after the first step, a second step of irradiating the laser light along the inner peripheral portion of the outer peripheral path in a state in which the output is adjusted so as to melt the metal plate of the uppermost layer of the laminate without penetrating it. Therefore, the edge generated in the inner peripheral portion of the welded portion welded in the first step can be melted by the laser beam irradiated in the second step. As a result, the appearance and paintability of the welded laminate can be improved, and the quality can be improved, compared to those with edges.

Further, in the second step, the laser beam is emitted through a first path extending along an inner peripheral portion of the outer peripheral path and a second path extending along an inner peripheral portion of the outer peripheral path in a direction opposite to the first path. Irradiation with light is preferred.

According to this configuration, the appearance and paintability of the laminated body after welding can be further improved, and the quality can be further improved.

A laminate of the present invention is a laminate formed by stacking a plurality of metal plates and laser-welded, wherein the lower surface of the lowermost metal plate among the plurality of metal plates is laser-welded. The welded portion extends so as to surround a predetermined portion of the lowermost metal plate, and is formed in a shape in which at least a portion is open, and is formed on the upper surface of the uppermost metal plate among the plurality of metal plates. In the above, the welded portion is formed in a recessed shape.

According to the laminate of the present invention, on the upper surface of the uppermost metal plate among the plurality of metal plates, the welded portion is formed in a recessed shape, so that the welded portion does not have an edge protruding upward. It is possible to improve the appearance and paintability of the laminated body after welding and improve the quality compared to those with edges.

The front view which shows the laser welding apparatus and robot of this invention. FIG. 4 is a top view showing a laminated body and a peripheral path of laser light in a first state; III-III cross-sectional view showing a laminate welded by laser light in a first state. FIG. 4 is a top view showing a laminated body, a peripheral path of laser light in a first state, and first and second paths of laser light in a second state; FIG. 5 is a cross-sectional view VV showing a laminated body irradiated with laser light in a second state after being welded with a laser light in a first state;

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings.

As shown in FIG. 1, a laser welding apparatus 10 for executing the laser welding method of the present embodiment includes a laser irradiation unit 11 that irradiates a laser beam L, and a laser control unit 12 that controls driving of the laser irradiation unit 11. Prepare. A laser welding apparatus 10 joins a laminate 15 composed of a first metal plate W1 and a second metal plate W2 used for a vehicle. The laminate 15 is placed on a support jig (not shown) and joined by the laser welding apparatus 10 while being sandwiched between the support jig and a clamper (not shown). Note that FIG. 1 schematically illustrates the laser welding device 10 and the laminate 15 .

The laser irradiation unit 11 includes a laser oscillator 11a. Further, the laser irradiation unit 11 includes, for example, an X-axis galvanometer mirror that scans the laser beam from the laser oscillator 11a in the X-axis direction, and a Y-axis galvanometer that scans the laser beam scanned by the X-axis galvanometer mirror in the Y-axis direction. It has a mirror and a condensing lens. In addition, the laser irradiation unit 11 includes an X-axis motor for rotating the X-axis galvanometer mirror, a Y-axis motor for rotating the Y-axis galvanometer mirror, and a known galvanometer scanner 11b having a control driver (none of which is shown). and Note that the structure of the galvanometer scanner 11b can be changed as appropriate.

The galvanometer scanner 11b rotates the X-axis galvanometer mirror and the Y-axis galvanometer mirror to appropriate angles by means of the X-axis motor and the Y-axis motor whose rotation angles are controlled by the control driver, thereby irradiating the target position with the laser beam. .

The laser irradiation unit 11 is attached to the first arm 17 a of the robot 17 . The robot 17 is, for example, a multi-axis multi-joint type robot, and is provided with first to fourth arms 17a to 17d in order from the tip. The robot 17 is provided with a plurality of motors (not shown) for driving the respective arms 17a to 17d, and the driving thereof is controlled by the robot controller . A base portion of the robot 17 is supported by the ground or a pedestal (not shown) fixed to the ground.

By driving a plurality of motors of the robot 17, the robot control device 18 drives each of the arms 17a to 17d, controls the position and orientation of the laser irradiation unit 11 attached to the arm 17a, and controls the laser irradiation unit 11. is moved to the joint portion of the laminate 15 .

[Metal plate welding]
Next, a laser welding method for the first and second metal plates W1 and W2 by the laser welding device 10 will be described.

First, as shown in FIG. 1, the robot controller 18 drives a plurality of motors of the robot 17 to drive the respective arms 17a to 17d, and the laser irradiation unit 11 is moved by the support jig and the clamper. It is controlled to maintain substantially the same distance from the upper surface of the sandwiched laminate 15 (the upper surface of the first metal plate W1) (hereinafter referred to as "same distance control").

Then, the robot control device 18 drives each of the arms 17a to 17d while performing the same distance control described above to move the laser irradiation section 11, for example, rightward in FIGS. 1 to 5 at a constant speed.

As shown in FIGS. 2 and 3, the laser control unit 12 operates the laser oscillator 11a and the galvanometer scanner 11b of the laser irradiation unit 11 which is moved at a constant speed in the right direction in FIGS. The laser light L in the first state whose output (energy) is adjusted so as to melt the first metal plate W1 and the second metal plate W2 of No. 15 is irradiated (first step). In this first step, the laser control unit 12 directs the laser beam L in the first state to a substantially arc-shaped outer peripheral path OR that extends so as to surround the predetermined portion 15a of the laminate 15 and that is at least partially open. (first step). It should be noted that the arrow of the outer circumference route OR indicates the moving direction of the route.

In this embodiment, the laser beam L in the first state is emitted along the outer circumference path OR while moving the laser irradiation unit 11 rightward in FIGS. 1 to 5 at a constant speed. The outer peripheral path OR has a leftward portion in FIGS. 2 and 3. In this portion, the distance from the laser irradiation unit 11 moving to the right to the outer peripheral path OR becomes longer, and the laser in the first state It is necessary to change the irradiation direction of the light L as well. In response to this, the laser control unit 12 operates the galvanometer scanner 11b to change the scanning directions of the X-axis galvanometer mirror and the Y-axis galvanometer mirror, thereby changing the irradiation direction of the laser light L in the first state. Thus, the laser beam L in the first state is controlled to irradiate along the outer circumference path OR.

As a result, the laser beam L in the first state is irradiated along the outer peripheral path OR, and a bead 25 (the hatched portion in FIGS. 2 and 4) is formed in the shape of the outer peripheral path OR so as to surround the predetermined portion 15a. , the laminate 15 is joined.

Next, as shown in FIGS. 4 and 5, the laser control unit 12 operates the laser oscillator 11a and the galvanometer scanner 11b of the laser irradiation unit 11 which moves rightward in FIGS. 4 and 5 at a constant speed. , the second state laser light L whose output is adjusted so as to melt without penetrating the first metal plate W1 of the uppermost layer of the laminate 15 is irradiated (second step). In this second step, the laser control unit 12 directs the laser beam L in the second state to the first path R1 extending along the inner peripheral portion of the outer peripheral path OR and the outer peripheral path OR in the direction opposite to the first path R1. Irradiation is performed through a second route R2 extending along the inner peripheral portion.

Similarly to the control of the irradiation direction of the laser beam L in the first state, even when the distance from the laser irradiation unit 11 moving rightward to the first route R1 and the second route R2 changes, the laser control unit 12 , the galvanometer scanner 11b is operated to change the scanning directions of the X-axis galvanometer mirror and the Y-axis galvanometer mirror to change the irradiation direction of the laser beam L in the second state, thereby changing the laser beam L in the second state to the second state. Control is performed to irradiate along the first route R1 and the second route R2.

As a result, the portion of the surface of the first metal plate W1 irradiated with the laser beam L in the second state (the portion marked with thin ink in FIG. 4) is melted to form a hollow shape D. The irradiation range of the laser beam in the second state should include at least the first route R1, and the outer peripheral route OR and the first route R1 may be continuous or spaced apart.

In the present embodiment, the portion where the bead 25 is formed (the portion where the first metal plate W1 and the second metal plate W2 are welded) has a substantially circular arc shape (peripheral path OR) that is partially open. , the air in the gap between the first metal plate W1 and the second metal plate W2 can be discharged from the opened portion. As a result, inside the portion where the first metal plate W1 and the second metal plate W2 are welded, the air in the gap between the first metal plate W1 and the second metal plate W2 thermally expands to damage the bead 25. never

When the laser beam L in the first state is irradiated along the outer path OR, an edge E projecting upward is generated on the inner peripheral portion of the bead 25 . In addition, in FIG. 3, the edge E is exaggerated and drawn.

In the present embodiment, the laser light L in the second state is irradiated along the first route R1 extending along the inner peripheral portion of the outer peripheral route OR (bead 25) (second step). The output of the laser beam L in the second state is adjusted so as to melt without penetrating the first metal plate W1 of the uppermost layer of the laminate 15 .

As shown in FIG. 4, the inner peripheral portion of the bead 25 (the hatched portion) overlaps the portion irradiated with the laser beam L in the second state (the shaded portion in FIG. 4). Therefore, as shown in FIG. 5, the laser beam L in the second state melts the edge E formed on the inner peripheral portion of the bead 25, and does not generate a new edge. As a result, the appearance and paintability of the laminated body 15 after welding can be improved, and the quality can be improved.

Further, as a result of diligent studies by the present applicant, when the laser beam L in the first state is irradiated along the outer peripheral path OR, a recess C (see FIG. 3) is generated in the final portion of the outer peripheral path OR (bead 25). I found out to do. In this embodiment, the laser beam L in the second state melts the surface of the first metal plate W1 (the surface of the inner peripheral portion of the outer peripheral path OR) and flows into the recess C, filling a part of the recess C. (See Figure 5). As a result, the appearance and paintability of the laminate 15 can be improved, and the quality can be improved.

While the laser irradiation unit 11 is moved at a constant speed in the right direction in FIGS. Control is performed so that the first step and the second step are performed. As a result, as shown in FIG. 1, the laminate 15 is spot-welded at predetermined intervals and firmly joined.

In the above-described embodiment, the outer circumference path OR is formed in a substantially arc shape, but any outer circumference path that is partially open may be used, such as a polygonal or elliptical shape.

In the above-described embodiment, the laser beam in the second state is irradiated through the first route R1 and the second route R2, but it is sufficient to irradiate the laser light through at least the first route R1. Further, the outer circumference route OR and the first route R1 may be continuous or may be spaced apart.

Moreover, all of the components shown in the above embodiments are not necessarily essential, and can be appropriately selected without departing from the gist of the present invention.

DESCRIPTION OF SYMBOLS 10... Laser welding apparatus, 15... Laminate, L... Laser beam, OR... Peripheral path, R1... First path, R2... Second path, W1... First metal plate, W2... Second metal plate

Claims (3)

A laser welding method for joining by irradiating a laser beam to a laminate configured by stacking a plurality of metal plates,
Irradiation of the laser beam along an outer peripheral path that extends to surround a predetermined portion of the laminate and is at least partially open while the output of the laser beam is adjusted so that the laminate can be melted. a first step of irradiating such that the position continuously moves from one end of the outer peripheral path to the other end ;
After the first step, the output of the laser beam is adjusted so that the metal plate of the uppermost layer of the laminate is melted without penetrating it, and the irradiation position of the laser beam is in the turn direction. a U-turn path that makes a U-turn from the other end of the outer peripheral path to the inner peripheral side of the outer peripheral path without leaving a gap inside; a second step of continuously irradiating an inner peripheral path formed on the inner peripheral side of the outer peripheral path while overlapping with the outer peripheral path in a direction opposite to the outer peripheral path ;
A laser welding method comprising: In the laser welding method according to claim 1,
In the second step, a first route as the inner peripheral route , and an irradiation route after irradiating the first route, which is opposite to the first route and along the inner peripheral portion of the first route A laser welding method, characterized in that the laser beam is radiated through a second path extending in a vertical direction. A laminate formed by stacking a plurality of metal plates and laser-welded,
The laser-welded welded portion penetrates the laminate, extends to surround a predetermined portion of the upper surface of the laminate when viewed from the top of the laminate , and is at least partially open. is formed by
a depression is formed on the top surface of the laminate along the welded portion;
In a top view of the laminate, the recess overlaps the entire welded portion at one end of the welded portion and protrudes toward the inner peripheral side of the welded portion. and extending along the inner periphery of the welded portion while partially overlapping the inner peripheral edge of the welded portion at a portion other than the end of the welded portion .

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