JPH04167987A - Laser beam welding apparatus - Google Patents

Abstract

PURPOSE:To enable good welding at high velocity by arranging optical system intentionally developing astigmatism in the laser beam system, making a first focal line and a second focal line and positioning the first focal line and the second focal line to welding part. CONSTITUTION:In the case of the optical system developing the astigmatism, slender focal line is generally developed in the first focal line F1 and the second focal line F2 and on the focal line, as irradiating beam source varies in proportion to liner of length (irradiating width) to the longitudinal direction, while securing the necessary irradiating beam intensity, the irradiating width can be optionally adopted to wide. At the time of the laser beam welding, by suitably selecting either the first focal line or the second focal line according to the irradiating width, the laser beam may be positioned to the welding part. As the optical system intentionally developing the astigmatism, the first focal line and the second focal line can be made by assembling the lens of recessed or projected cylindrical lens, etc., or a mirror of paraboloid mirror, etc. By this method, while securing the necessary irradiating beam intensity to the welding with the simple constitution, the irradiating width is adopted to wide and the good welding is executed at high velocity.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a laser welding device, and particularly relates to a laser welding device for welding steel plates, particularly Z
The present invention relates to a laser welding device suitable for welding surface-treated steel plates such as n-plated steel plates and zinc primer coated steel plates, or welding aluminum materials and surface-treated aluminum materials.

(Prior Art and Problems to Be Solved) Conventionally, a butt laser welding method for boat fishing has been carried out as shown in FIG. That is, the laser beam 9 is narrowed down to approximately Q, 3m11φ by the spherical lens 3, and is irradiated to the welded part 1o where the workpieces (base metal) 1.2 are butted together.
This is a method of joining by melting 0.

However, this method has drawbacks such as drop-off of the weld if there is a misalignment in the weld, and a decrease in weld strength due to changes in the chemical composition of the weld due to laser irradiation.

Therefore, in order to solve this problem, as shown in Figure 2,
A method is often adopted in which a welding wire 8 is inserted into the welded part to prevent melt drop and chemical composition changes.

However, even with this method, as shown in FIG. 3, since the welding wire itself has curls, the width of the laser beam irradiation for welding needs to be about 2 to 51 mm. Even if the curl of the welding wire can be eliminated, the diameter of the wire is 1 to 2 mm, so the focus spot 1 is 0.3 mm.
1 cannot melt the welding wire sufficiently, so
The irradiation width must be wide.

The following methods can be used to widen the irradiation width.

First, as shown in FIG. 4, there is a method of scanning the laser beam 9 with a movable mirror 12, but this requires a movable mechanism and further requires the use of a flat field lens with good characteristics as the spherical lens 3. There are restrictions.

Further, as shown in FIG. 5, the fixed mirror 13 and the lens 3
There is also a method of vibrating at the same time using the parallel displacement device 14,
There are disadvantages such as the equipment becomes large-scale.

Furthermore, in the beam scanning method shown in Figures 4 and 5, if you want to increase the welding speed, it is naturally necessary to increase the scan frequency, but methods that achieve high-speed scanning are generally expensive. There is a problem with becoming.

Another method of widening the irradiation width without using a movable part is to place the workpiece 1.2 at a position away from the focal point F of the spherical lens 3 (day focus), as shown in Figure 6. However, since the intensity of the irradiated light decreases in proportion to the square of the irradiation width, there are drawbacks such as not being able to obtain the energy necessary for welding at the condensed spot 11.

As mentioned above, in the method of laser welding without inserting the welding wire, it is necessary to have a wide laser irradiation width, but in this case, (1) welding with high irradiation light intensity without shifting the focal position; To do this, the beam must be scanned, but the scanning mechanism is bulky and the components are expensive.

(2) In order to widen the irradiation width using a spherical lens without scanning the beam, it is necessary to place the workpiece at a position away from the focal point, but the irradiation light intensity decreases in proportion to the square of the irradiation width. The energy necessary for welding cannot be obtained.

The present invention solves the problems described above when performing laser welding without inserting a welding wire, and enables laser welding to easily widen the irradiation width while ensuring the irradiation light intensity necessary for welding. The purpose is to provide a device.

(Means for Solving the Problems) In order to solve the above problems, the present inventors have conducted extensive research on optical systems used when performing laser welding without inserting a welding wire, and have hereby devised the present invention. This is what was done.

That is, the present invention provides an apparatus for welding with a laser beam while inserting a welding wire, in which the laser beam system is provided with an optical system that intentionally generates astigmatism to create a first radio and a second radio. The gist of the present invention is a laser welding apparatus characterized by having a configuration in which a radio or a second radio is located at a welding part.

The present invention will be explained in more detail below.

(Function) As described above, the present invention provides an optical system that intentionally generates astigmatism in a laser beam system, thereby eliminating the need for expensive components such as flat field lenses and high-speed scanning components, and large-scale movable mechanisms. This device enables high-speed welding without being affected by the curl or thickness of the wire, while ensuring the necessary irradiation light intensity for welding with a simple mechanism.

In the case of an optical system in which astigmatism is used in the present invention, as shown in FIG. This is because the irradiation light intensity changes only in proportion to the first power of the length in the longitudinal direction (irradiation width), so the irradiation width can be arbitrarily widened while ensuring the necessary irradiation light intensity.

Therefore, when laser welding, depending on the irradiation width,
Either the first radio or the second radio may be appropriately selected and positioned at the welding part.

Various modes are possible for an optical system that intentionally generates astigmatism. The first radio and the second radio can be created by using one or more lenses such as a concave or convex cylindrical lens or a spherical lens, or mirrors such as a parabolic mirror or a cylindrical mirror, either singly or in combination.

Of course, other configurations of the laser beam welding device are not particularly limited. In addition to butt welding, it can also be applied to welding other joint shapes.

The laser welding device of the present invention can be applied to welding various materials to be welded, but is particularly suitable for welding surface-treated steel sheets such as Zn-plated steel sheets and zinc primer-coated steel sheets, or for welding aluminum materials and surface-treated aluminum materials. ing.

(Example) Next, examples of the present invention will be shown.

Embodiment 1 - In this example, as shown in FIG. 8, the laser beam 9 is first focused by a spherical lens 3 and then focused by a convex cylindrical lens 4 to create a first radio F1 and a second radio F. It is. The welded portion 10 of the workpiece 1.2 is placed perpendicularly to the second radio F2. Then, a welding wire 8 is inserted into the intersection of this welding part [0] and the second radio F2, and welding is performed while moving the workpiece.

In addition, Fig. 9 shows Fig. 8 from six directions, and Fig. 10 shows B.
It is a figure seen from the direction. Further, FIG. 11 shows the shape of the radio, where Ql is the radio length and Q2 is the radio width.

In Fig. 8, if the laser beam diameter is 50 mm, the focal length f1 of the spherical lens 3 is 127 mm, the focal length f2 of the convex cylindrical lens 4 is 300 cm, and the distance d between 3 and 4 is 6C) + m. , the second radio F2 can be located at a position L=67t+++ from the convex cylindrical lens. At this time,
The length Ql of the second radio F2 is approximately 5 mm, and the width Q2 is approximately 50 μ.
- It will be about. If a 5Kw CO2 laser or the like is used as the laser, the intensity of the irradiated light will be about 20GW/m2.

Under this light intensity, Zn-plated steel plates etc.
It is possible to weld at a high speed of 00cs+/■in.

The optical system shown in FIG. 12 is an astigmatism optical system that uses a concave cylindrical lens 5 instead of a convex cylindrical lens.

The optical system shown in FIG. 13 is an astigmatism optical system using two convex cylindrical lenses 4.

The optical system shown in FIG. 14 is an astigmatism optical system in which the spherical lens 3 is tilted.

The optical system shown in FIG. 15 is an astigmatism optical system using a parabolic mirror 7 and a cylindrical mirror 6.

Any of these astigmatism optical systems, as in Example 1,
The first radio F and the second radio F2 can be created, and arbitrary irradiation light intensity and irradiation width can be obtained.

(Effects of the Invention) As detailed above, according to the present invention, the irradiation width can be widened while ensuring the irradiation light intensity necessary for welding with a simple configuration. Therefore, there is no need for expensive and complicated configurations associated with movable parts such as scanning mechanisms, and high-speed and good welding is possible.

[Brief explanation of drawings]

Figure 1 is a diagram explaining the procedure for butt laser welding.
(a) is a plan view, (b) is a sectional view, and FIGS. 2 and 3 are diagrams illustrating the procedure for laser welding without inserting a welding wire; (a) is a plan view, and ( b) is a cross-sectional view, Figures 4 and 5 are diagrams explaining the method of scanning the laser beam, Figures 6 (a) and (b) are diagrams explaining day focus, and Figure 7 is a diagram explaining the method of scanning the laser beam. 8 is a perspective view illustrating an example of an astigmatism optical system, FIG. 9 is a view seen from six directions of FIG. 8, and FIG. 10 is a diagram illustrating an example of an astigmatism optical system. FIG. 11 is a diagram for explaining the shape and dimensions of the radio, and FIGS. 12 to 15 are diagrams for explaining different examples of astigmatism optical systems. ) is a view seen from the moving direction, and (b) is a view seen from a direction perpendicular to the moving direction. 1, 2... Workpiece, 3... Spherical lens, 4... Convex cylindrical lens, 5... Concave cylindrical lens, 6...
・Cylindrical mirror, 7 ・Parabolic mirror, 8...
Welding wire, 9... Laser light, 10... Welding part, F□
...1st radio, F2 2nd radio. Patent Applicant Kobe Steel Co., Ltd. Patent Attorney Hisashi Nakamura <===ko Figure 3] O Figure 4 Figure 5 Figure 6] 0 Figure 7 Ku> Figure 12 (G) (b) (G) (b) Fig. 14 (G) (b) Fig. 15 (G) (b)

Claims (1)

[Claims] In an apparatus for welding with a laser beam while inserting a welding wire, an optical system that intentionally generates astigmatism is provided in the laser beam system to create a first radio and a second radio;
A laser welding device characterized in that the first radio or the second radio is located at a welding part.