German companies develop laser welding for solar absorber manufacturing

March 4, 2011

In a cooperative project, Laser Zentrum Hannover e.V., Hannover, Germany, and Flexxibl GmbH, Brunswick, Germany, have developed a new laser welding process for solar absorber manufacturing. The main element, a diode laser, is used to join the copper tubes to the aluminum absorber sheet.

The Joining and Separating of Metals group of LZH’s materials and processing department uses only one 4-kW diode laser for the welding process. Copper and aluminum both have high absorption characteristics for the typical diode laser wavelengths used (800 to 980 nm). Welding spot size can be increased for higher weld stability. The thermal input can be regulated to prevent excessive thermal load that could damage the absorber coating.