Laser welding method and laser welding apparatus

Abstract

To provide a laser welding method and a laser welding device which can avoid workpiece defects caused by making gasified metal jetted during laser welding of the workpiece collide with the workpiece.SOLUTION: A laser welding device welds workpiece 50 stacked in layers using a laser beam, wherein the laser welding device includes a first laser irradiation device, and a driving device which relatively moves one of the first laser irradiation device of the workpiece to the other of the first laser irradiation device and the workpiece, a laser irradiation angle A of the first laser irradiation device is arranged so as to be positioned on the side opposite to a welding progress direction D, and the laser welding device allows the first laser irradiation device to irradiate the workpiece with the laser beam in an infocus state by adjusting the height of the first laser irradiation device to the workpiece.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a welding method and a welding apparatus, and particularly to a laser welding method and a laser welding apparatus.

Background Art

[0002] A galvanized steel sheet structure is generally formed by combining a plurality of stacked galvanized steel sheets through a laser welding process. In the process of performing a laser welding process on a galvanized steel sheet, when the holes generated by laser irradiation of the workpiece (galvanized steel sheet) are excessively small, the gasified metal ejected during laser welding of the workpiece is likely to hit the workpiece, which may cause defects in the workpiece. Therefore, it is necessary to improve the laser welding apparatus to overcome the above problems.

Summary of the Invention

[0003] The present invention provides a laser welding method and a laser welding apparatus capable of avoiding workpiece defects caused by the collision of gasified metal ejected during laser welding of a workpiece with the workpiece.

[0004] The present invention provides a laser welding method for welding a workpiece in which a plurality of plate materials are stacked using a laser. In the step of relatively moving the laser and the workpiece in a state where the laser irradiates the workpiece and welding is performed, the irradiation angle is provided so that the laser tilts in a direction opposite to the welding progress direction to irradiate the laser, and the focus of the laser is irradiated so that it is located in front of the welding progress direction from the hole generated by the irradiation of the laser on the workpiece.

[0005] In an embodiment of the present invention, the distance between the laser irradiator and the workpiece is adjusted so that the laser is irradiated in an in-focus manner.

[0006] In embodiments of the present invention, the laser's moving speed or the laser's output is controlled so that the focal point is located ahead of the hole in the welding direction.

[0007] In an embodiment of the present invention, the laser is irradiated such that, when the laser is tilted at the irradiation angle, the length extending forward from the hole in the welding direction is X, and the opening size of the hole is D, the distance calculated by multiplying the laser's moving speed by the time it takes for the workpiece to gasify due to the laser irradiation is longer than D + X.

[0008] In an embodiment of the present invention, a second laser is irradiated toward the hole opening downstream in the welding direction from the irradiation position of the first laser.

[0009] The present invention provides a laser welding apparatus for welding a workpiece made of multiple stacked plates using a laser, comprising: a drive device for moving one of the laser and the workpiece relative to the other of the laser and the workpiece; and a first laser irradiator positioned with an irradiation angle such that the laser is tilted in the opposite direction to the welding direction, wherein the laser is irradiated such that the focal point of the laser is located in front of the hole generated by the irradiation of the workpiece with the laser, in the direction of welding.

[0010] In an embodiment of the present invention, the height of the first laser irradiator relative to the workpiece is adjusted so that the laser is irradiated in focus.

[0011] In an embodiment of the present invention, the laser welding apparatus further comprises a control unit that controls at least one of the laser's moving speed or the laser's output so that the focal point is located ahead of the hole in the welding direction.

[0012] In an embodiment of the present invention, when the length of the laser's melting depth that extends forward from the hole in the welding direction when the laser is tilted at the irradiation angle is X, and the opening size of the hole is D, the control unit irradiates the laser such that the distance calculated by multiplying the laser's moving speed by the time it takes for the workpiece to gasify due to the laser irradiation is longer than D + X.

[0013] In an embodiment of the present invention, the laser welding apparatus further comprises a second laser irradiator that irradiates a second laser toward a hole opening downstream in the welding direction from the irradiation position of the first laser irradiator.

[0014] Based on the above, in the laser welding method and laser welding apparatus of the present invention, the laser irradiation angle of the first laser irradiator is positioned on the opposite side to the welding direction, and the first laser irradiator irradiates the workpiece with the laser in focus, thereby increasing the area of ​​the holes generated in the workpiece by the first laser irradiator irradiating the workpiece with the laser. As a result, the gasified metal ejected from the workpiece during laser welding can easily pass through the holes and separate from the workpiece. Thus, the laser welding method and laser welding apparatus of the present invention can avoid workpiece defects caused by the gasified metal ejected during laser welding of the workpiece colliding with the workpiece.

[0015] To make the above-mentioned features and advantages of the present invention clearer and easier to understand, embodiments are described below and explained in detail with reference to the accompanying drawings. [Brief explanation of the drawing]

[0016] [Figure 1] This is a schematic diagram of a laser welding apparatus according to one embodiment of the present invention. [Figure 2] Figure 1 shows the laser irradiating the workpiece. [Figure 3] This is a schematic diagram of a laser welding apparatus according to another embodiment of the present invention. [Figure 4] Figure 3 shows the laser irradiating the workpiece. [Modes for carrying out the invention]

[0017] Figure 1 is a schematic diagram of a laser welding apparatus according to one embodiment of the present invention. Figure 2 is a diagram showing the laser of Figure 1 irradiating a workpiece. Referring to Figures 1 and 2, the laser welding apparatus 100 of this embodiment welds a workpiece 50 made by stacking multiple galvanized steel plates 52 using a laser L, and the laser welding apparatus 100 comprises a first laser irradiator 110 and a drive device 120. The drive device 120 moves one of the first laser irradiator 110 and the workpiece 50 relative to the other of the first laser irradiator 110 and the workpiece 50. In this embodiment, the drive device 120 is, for example, connected to the first laser irradiator 110 and drives the first laser irradiator 110 to move relative to the workpiece 50 along the welding direction D.

[0018] In this embodiment, the laser irradiation angle A of the first laser irradiator 110 is positioned on the opposite side from the welding direction D. That is, the optical axis OA of the laser L is inclined backward in the welding direction D toward the workpiece 50. Specifically, the first laser irradiator 110 irradiates the workpiece 50 with the laser L along the irradiation direction E, creating a hole 501 in the workpiece 50. The irradiation direction E is parallel to the optical axis OA of the laser L, the reference plane S is perpendicular to the welding direction D and intersects the hole 501 at the leading edge 501a in the welding direction D, and the optical axis OA of the laser L is directed toward the reference plane S at the laser irradiation angle A from the reference plane S and is inclined backward in the welding direction D.

[0019] Furthermore, in this embodiment, the laser L is irradiated onto the workpiece 50 in focus by adjusting the height of the first laser irradiator 110 relative to the workpiece 50. Specifically, the laser welding apparatus 100 of this embodiment further comprises a control unit 130, and the height of the first laser irradiator 110 relative to the workpiece 50 is controlled, for example, by the control unit 130, and the control unit 130 controls at least one of the moving speed of the drive unit 120 and the output of the first laser irradiator 110, thereby positioning the focal point F of the laser of the first laser irradiator 110 in front of the hole 501 in the welding direction D.

[0020] As described above, in the laser welding method and laser welding apparatus 100 of this embodiment, the laser irradiation angle A of the first laser irradiator 110 is located on the opposite side of the welding direction, and the first laser irradiator 110 irradiates the workpiece 50 with the laser L in focus, thereby increasing the area of ​​the holes 501 generated in the workpiece 50 by the first laser irradiator 110 irradiating the workpiece 50 with the laser L. Based on this, the gasified metal ejected from the workpiece 50 during laser welding can easily pass through the holes 501 and separate from the workpiece 50. As a result, the laser welding method and laser welding apparatus 100 of this embodiment can avoid workpiece defects caused by the gasified metal ejected during laser welding of the workpiece 50 colliding with the workpiece 50. In addition, the energy density of the laser L in the depth direction of the holes 501 is increased, which allows for the formation of deeper holes 501, thereby increasing the welding speed and enabling the welding of thick and / or high-melting-point workpieces.

[0021] In this embodiment, the control unit 130 controls the movement speed of the drive unit 120, thereby preventing the laser L from moving at an excessively high speed. This avoids the problem of insufficient energy for the laser L to irradiate the workpiece 50, leading to unstable formation of the hole 501, and also prevents the ejected gaseous metal from moving directly backward in the hole 501 and not moving upward outside the hole 501, which can also be caused by an excessively high laser L movement speed. Furthermore, the control unit 130 controls the movement speed of the drive unit 120, thereby preventing the laser L from moving at an excessively low speed. This avoids the problem of excessive energy for the laser L to irradiate the workpiece 50, leading to unstable formation of the hole 501, and also prevents the area of ​​the hole 501 from being excessively small, which can also be caused by an excessively high laser L movement speed, making it difficult for the ejected gaseous metal to pass through the hole 501 and leave the workpiece 50.

[0022] Figure 3 is a schematic diagram of a laser welding apparatus according to another embodiment of the present invention. Figure 4 shows the laser of Figure 3 irradiating a workpiece. The difference between the embodiments shown in Figures 3 and 4 and those shown in Figures 1 and 2 is that the laser welding apparatus 100A shown in the embodiments of Figures 3 and 4 further comprises a second laser irradiator 140. The first laser irradiator 110 irradiates the workpiece 50 with a laser L at the first laser irradiation position P1, and the second laser irradiator 140 irradiates the opening H of the hole 501' with a laser at the second laser irradiation position P2, where the second laser irradiation position P2 is located downstream of the first laser irradiation position P1 in the welding direction D. This makes it possible to further increase the area of ​​the hole 501' and the energy density of the laser in the depth direction of the hole 501'.

[0023] To summarize the above, in the laser welding method and laser welding apparatus of the present invention, the laser irradiation angle of the first laser irradiator is located on the side opposite to the welding progress direction, and the first laser irradiator irradiates the work with the laser in an in-focus state, so that the area of the hole generated in the work when the first laser irradiator irradiates the work with the laser is increased. Based on this, the gasified metal ejected from the work during laser welding easily passes through the hole and separates from the work. Thereby, the laser welding method and laser welding apparatus of the present invention can avoid work defects caused by the gasified metal ejected during laser welding of the work colliding with the work.

[0024] Finally, it should be noted that the above embodiments are only used to explain the technology of the present invention and do not limit the present invention. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can modify the technology described in the above embodiments or perform equivalent replacements for some or all of the technical features thereof. For example, in this embodiment, a galvanized steel sheet is used as the work 50, but it is not limited thereto. The material of the work 50 is not limited as long as it is a metal that can be fusion-welded by a laser welding apparatus, and it may be aluminum, copper, or the like. These modifications or replacements do not deviate from the essence of the corresponding technology from the scope of the technology of the embodiments of the present invention.

Description of Reference Numerals

[0025] 50: Work 52: Galvanized Steel Sheet 501a: Front Edge 100, 100A: Laser Welding Apparatus 110: First Laser Irradiator 120: Driving Device 130: Control Unit 140: Second Laser Irradiator 501: Hole A: Laser Irradiation Angle D: Welding Progress Direction E: Irradiation Direction F: Focus L, L’: Laser OA: optical axis P1: First laser irradiation position P2: Second laser irradiation position S: Reference plane

Claims

1. A laser welding method for welding a workpiece made by stacking multiple plate materials using a laser, In the process of welding by moving the laser and the workpiece relative to each other while the laser is irradiated onto the workpiece, The laser is irradiated with an irradiation angle set such that the laser is tilted in the opposite direction to the welding direction. The laser is irradiated such that the focal point of the laser is located in front of the hole generated by the irradiation of the workpiece with the laser in the welding direction. A second laser is irradiated toward the hole opening downstream in the welding direction from the irradiation position of the first laser. Characterized by, Laser welding method.

2. A laser welding apparatus that uses a laser to weld a workpiece made of multiple stacked plates, A drive device that moves one of the laser and the workpiece relative to the other of the laser and the workpiece. A first laser irradiator is positioned such that the laser is tilted in the opposite direction to the welding direction, Equipped with, The laser is irradiated such that the focal point of the laser is located in front of the hole generated by the irradiation of the workpiece with the laser in the welding direction. A second laser irradiator irradiates a second laser toward the hole opening downstream in the welding direction from the irradiation position of the first laser irradiator. It also has Characterized by, Laser welding equipment.

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