초록 ▼

The invention relates to a method for the laser welding of a composite material (V) to a component (11) in particular for the production of a solar collector element (E), wherein the composite material (V) comprises a strip-shaped substrate (1) composed of a metal having high reflectivity to laser r

The invention relates to a method for the laser welding of a composite material (V) to a component (11) in particular for the production of a solar collector element (E), wherein the composite material (V) comprises a strip-shaped substrate (1) composed of a metal having high reflectivity to laser radiation, said substrate having a first side (A) and a second side (B), wherein a dielectric coating (7) is situated at least on the first side (A), and wherein, in order to produce a weld seam, a laser beam (L) is projected at an acute orientation angle (μ) at least onto the first side (A) of the substrate (1) provided with the dielectric coating (7). In order to improve the energy efficiency of the laser radiation used, it is proposed that the dielectric coating (7) has a thickness (DB) in the range of 140 nm to 210 nm and the laser beam (L) is radiated in at an orientation angle (μ), in particular in focused fashion, in such a way that the radiated-in energy of the laser beam (L) is absorbed to the extent of at least 15 percent.

대표청구항 ▼

1. A method for the laser welding of a composite material (V) to a component (11) for the production of a solar collector element (E), the method comprising the steps of: providing the composite material (V) comprising a strip-shaped substrate (1) composed of a metal having high reflectivity to lase

1. A method for the laser welding of a composite material (V) to a component (11) for the production of a solar collector element (E), the method comprising the steps of: providing the composite material (V) comprising a strip-shaped substrate (1) composed of a metal having high reflectivity to laser radiation, said substrate having a first side (A) and a second side (B), wherein a dielectric coating (7) is situated at least on the first side (A), the dielectric coating (7) having a thickness (DB) in the range of 140 nm to 210 nm; andprojecting a laser beam (L) at an acute orientation angle (μ) at least onto the first side (A) of the substrate (1) provided with the dielectric coating (7), in order to produce one of a continuous weld seam and discrete weld spots, wherein the laser beam (L) is radiated in onto the composite material (V) in such a way that the radiated-in energy of the laser beam (L) is absorbed to the extent of at least 15 percent. 2. The method according to claim 1, characterized in that the laser beam (L) is focused optically, for example by means of lenses. 3. The method according to claim 2, characterized in that the laser beam (L) is focused by lenses. 4. The method according to claim 1, characterized in that the coating (7) is a ceramic coating. 5. The method according to claim 1, characterized in that the coating (7) has a thickness (DB) in the range of 170 nm to 195 nm. 6. The method according to claim 1, characterized in that the coating (7) has a thickness (DB) of less than 200 nm and the laser beam (L) is radiated in onto the composite material (V), in particular at an orientation angle (μ) in the range of 2° to 50°, in such a way that the radiated-in energy of the laser beam (L) is absorbed to the extent of at least 20 percent. 7. The method according to claim 1, characterized in that the laser beam (L) is radiated in onto the composite material (V) at an orientation angle (μ) in the range of 2° to 50°. 8. The method according to claim 7, characterized in that the orientation angle (μ) at which the laser beam (L) is radiated in onto the composite material (V) is less than 30°. 9. The method according to claim 7, characterized in that the focused laser beam (L) is radiated in onto the composite material (V) at an orientation angle (μ) in the range of 7° to 17°. 10. The method according to claim 1, characterized in that the laser beam (L) is linearly polarized in a single plane. 11. The method according to claim 10, characterized in that the laser beam (L) is polarized in such a way that its light lies parallel to an incidence plane (W) perpendicular to the interface between composite material (V) and component (11). 12. The method according to claim 1, characterized in that the coating (7) is substantially composed of aluminum oxide. 13. The method according to claim 1, characterized in that the substrate (1) of the composite material (V) is composed of aluminum. 14. The method according to claim 12, characterized in that the aluminum oxide of the coating (7) is formed from one of anodically oxidized, and electrolytically brightened and anodically oxidized, aluminum of which the substrate (1) is composed. 15. The method according to claim 1, characterized in that the component (11) is a tube (11). 16. The method according to claim 1, characterized in that the component (11) is composed of copper. 17. The method according to claim 1, characterized in that the component (11) and the composite material (V) are connected along an abutment joint of the component (11) and of the composite material (V) by means of weld seams running on both sides of the component (11). 18. The method according to claim 1, characterized in that each weld seam is formed from small molten balls (12) that are spaced apart from one another (distance a). 19. The method according to claim 18, characterized in that the energy of the laser beam (L) for producing a small molten ball (12) acts over a time period of not more than approximately 10 ms. 20. The method according to claim 1, characterized in that the power density of the laser beam (L) during welding does not exceed 106 W/cm2. 21. The method according to claim 1, characterized in that an Nd:YAG laser is used for producing the laser beam (L). 22. The method according to claim 1, characterized in that a dielectric coating (2) is situated on the second side (B) of the substrate (1). 23. The method according to claim 22, characterized in that the coating (2) on the second side (B) of the substrate (1) is produced identically to the coating (7) situated on the first side (A) of the substrate (1). 24. The method according to claim 1, characterized in that an optically active coating (3) is situated on the second side (B) of the substrate (1). 25. The method according to claim 24, characterized in that the optically active coating (3) is a multilayer system (3) composed of at least three layers (4, 5, 6). 26. The method according to claim 25, characterized in that, in the multilayer system (3), a topmost layer (4) is a dielectric layer, a middle layer (5) is a layer containing chromium oxide, and in that a bottommost layer (6) is composed of gold, silver, copper, chromium, aluminum and/or molybdenum. 27. The method according to claim 1, characterized in that a distance (b) between an impingement point (P) of the laser beam (L) and a tangent point (Q), at which the coating (7) of the composite material (V) touches the component (11), embodied as a tube (11), is not greater than 10 percent of a radius (R) of the tube (11).