JPS6057430B2 - Welding method using laser beam - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a welding method suitable for welding an upper plate and a lower plate together using a laser.

Laser beams have high energy density and can be narrowed down to a small beam diameter, making them suitable as an energy source for spot welding small parts made of dissimilar metals.
For example, it may be used when welding silver contacts to a copper plate.

In this case, as shown in Figure 2, the copper plate is used as the upper plate 1 and the silver contact is used as the lower plate 2, and the laser beam 3 is irradiated from the upper plate 1 side. However, because copper has high thermal conductivity, heat dissipates to the surroundings. In addition, even if the energy density of the beam is increased to melt the upper plate 1, the silver contact on the lower plate 2 is not heated sufficiently, making it difficult to obtain a good welding result. Have difficulty. Furthermore, in order to melt the lower plate 2, a through hole 1a is provided in the upper plate 1 as shown in Fig. 8a, and the laser beam 3 is irradiated with it, but the energy of the laser beam generally Because of the Gaussian distribution, the part with high energy density is irradiated onto the lower plate 2 through the through hole 1a, and while the lower plate 2 may have a hole, the upper plate 1 is not sufficiently melted and is not in good condition. However, it is still difficult to obtain accurate welding results, and in both cases there is a problem in that it is difficult to select welding conditions. The present invention has been made with the aim of solving these problems, and involves drilling holes in the upper plate, stacking the lower plate under the holes in the upper plate, and removing the areas where the energy density of the laser beam is high. By heating and melting the upper plate in the area of low energy density that has passed through the through-hole, the upper plate and lower plate can be welded while balancing the molten state of the upper plate and lower plate. The present invention provides a welding method using a laser beam that can obtain good welding results.

Some embodiments shown in the drawings will be described below.
FIG. 1 shows a first embodiment, in which a through hole 4 is provided in the upper plate 1 (for example, a copper plate) as shown in FIG. ) is placed on the upper plate 1b at the periphery of the through hole 4, and the laser beam 3 is irradiated with the laser beam 3 in such a manner that the periphery of the laser spot of the laser beam 3 overlaps to some extent.

The irradiated laser beam 3 hits the small piece 5 at a high energy density portion, and at the same time hits the lower plate 2 (for example, a silver contact) through the gap in the small piece 5, heating the lower plate 2, and further heats the lower plate 2.
Since the upper plate 1b around the area is also heated, by appropriately selecting the size and number of the small pieces 5, the upper plate 1b1, the small pieces 5, and the lower plate 2 can be heated and melted in a well-balanced manner, thereby achieving a good welding result. It is something that can be obtained. Figure 1b shows the welded part after welding, and the through hole 4 is connected to the small piece 5 and the upper plate 1.
b is filled by melting. 6 indicates a welded portion.

FIGS. 2 and 3 show a second embodiment, in which a plurality of small holes 7, 7, . The laser beam 3 is irradiated with the holes 7, 7, . . . entering the laser spot 3a.

In this embodiment, ζ melts the upper plate 1 in the high energy density part of the irradiated laser beam 3, and heats the lower plate 2 through the small hole 7 in the low energy density part. In this case, because of the small holes 7, the heat applied to the upper plate 1 is difficult to dissipate to the surrounding area, so the upper plate 1 is heated efficiently, and the upper plate 1,
Both the lower plates 2 are melted in a well-balanced manner to obtain a good welding result, and the small holes 7 are filled with the molten upper plate 1. FIG. 4 shows a third embodiment, in which a through hole 4 is provided in the upper plate 1, and the laser beam 3 is irradiated with the center of the laser spot located on the upper plate 1b around the through hole 4. upper plate 1 in areas with high energy density.
Since the lower plate 2 is heated through the through hole 4 in the lower energy density portion by melting the upper plate 1 and the lower plate 2 by appropriately selecting the size of the through hole 4 and the aiming position of the laser beam, By heating and melting in a well-balanced manner, it is possible to obtain good welding results. Figure 4b shows the welded part after welding, and the welded part 6 is offset to one side, but if the appearance is unfavorable, the laser beam aiming position can be set symmetrically on the opposite side. good. 5 and 6 show a fourth embodiment, in which a through hole 4 is provided in the upper plate 1, and the laser beam 3 is placed so that the periphery of the laser spot overlaps the upper plate 1 and b in the periphery of the through hole 4. The laser beam 3 is irradiated with a ring-shaped convex lens 8 to reduce the energy density at the center, so that the ring-shaped part with high energy density irradiates the upper plate 1b. The energy density at the center can be appropriately selected from completely zero to slightly lower than the periphery depending on the shape of the ring-shaped convex lens 8.
Since it is ring-shaped, the lower plate 2 will be heated and melted in the part with low energy density, and by appropriately selecting the shape of the laser spot 3b, the upper plate 1 and the lower plate 2 can be balanced. The material is heated and a good welding result can be obtained. As mentioned above, in the laser beam welding method of the present invention, a through hole is drilled in the upper plate, the lower plate is stacked under the through hole in the upper plate, and the upper plate is heated and melted by the part of the laser beam with high energy density. However, since the lower plate is heated and melted in the low energy density area that passes through the through hole, welding can be performed while balancing the molten state of the upper and lower plates, making it easy to set welding conditions. This method has the advantage of facilitating welding between dissimilar metals with high thermal conductivity, such as when welding a silver contact to a copper plate.

[Brief explanation of the drawing]

FIGS. 1A and 1B are a partially cutaway side view and a sectional view of a welded part showing the outline of one embodiment of the present invention, and FIGS. 2A and 2B are a partially cutaway side view and a sectional view showing the outline of another embodiment of the present invention. A top view of the welding location, Figure 3 is a partially broken slope view showing the same procedure as above, and Figure 4A.
, b is a partially broken side view and a sectional view of a welded part showing the procedure of another embodiment, FIG. 5 is a partially broken side view showing the procedure of another embodiment, and FIG. 6 is a partially broken side view showing the procedure of another embodiment. Perspective view shown, No. 7
The figure is a partially cutaway side view showing the main points of the conventional example, Figures 8A and b
FIG. 2 is a partially cutaway side view showing the gist of another conventional example and a diagram showing the energy distribution of a laser beam. 1 and 1b are upper plates, 2 is a lower plate, 3 is a laser beam, 3a,
3b is a laser spot, 4 is a through hole, 5 is a small piece, 7 is a small hole, and 8 is a ring-shaped convex lens.

Claims (1)

[Scope of Claims] 1. A through hole is drilled in the upper plate, a lower plate is stacked under the through hole in the upper plate, and the upper plate is heated and melted with a portion of high energy density of the laser beam, so that the laser beam passes through the through hole. A welding method using a laser beam, which is characterized by melting the upper plate and the lower plate while balancing the molten state of the upper plate and the lower plate by heating and melting the lower plate in an area with low energy density. 2 A through hole is made in the upper plate, one or more small pieces of the same material as the upper plate are placed in the through hole, and a laser beam is irradiated so that the periphery of the laser spot overlaps the upper plate around the through hole. The welding method using a laser beam according to claim 1, wherein the upper plate, the small piece, and the lower plate are respectively melted by doing so. 3 Multiple small holes were drilled at the welding points of the upper plate, and the laser beam was irradiated so that these small holes entered the laser spot, thereby melting the upper plate and the lower plate respectively. A welding method using a laser beam according to claim 1. 4 A patent that melts the upper plate and the lower plate by providing a through hole in the upper plate and irradiating a laser beam so that the center of the laser spot is located on the upper plate around the through hole. A welding method using a laser beam according to claim 1. 5. By providing a through hole in the upper plate and irradiating the upper plate around the through hole with a laser beam so that the periphery of the laser spot with a lower energy density in the center overlaps, the upper plate and the lower plate are separated. A welding method using a laser beam according to claim 1, wherein each of the welding parts is melted.