Lasers in Manufacturing (LiM)
In recent years, the production of individual, colored glass products has been increased. As a result, flexible production processes and short delivery times for glass finishers should be profitable. Currently, the colors have to be applied on the glass surface before tempering in the oven. As a result, the color will be burned with the glass. Therefore, the process is reserved for large companies with an oven for the production of toughened safety glass. In this project, a new process will be developed. The applied color is baked locally on the glass surface by laser radiation. Float glass was used for the investigations. Laser firing experiments were carried out with different color layers with thicknesses of about 30 μm. A coloring could be achieved by using a laser wavelength of 10.6 µm. The process limits were determined and the following phenomena were observed: no coloring is possible with low material stress; with adapted laser parameters, a coloring is visible; with an increase in the laser power, stresses in the glass were introduced. Therefore, the risk of crack initiation will be increased. The colors created with the oven fired process and with the laser process have identical appearances. Using the laser process, different colors could be burned locally on the glass surface and the production of large-format and colored images, for example in architectural glass, are possible.