Laser welding of glass components with glass fibers as a connecting material

Welding of non-rotational glass components requires filler material for gap bridging between the joining partners. The following work presents the investigation on glass welding using glass fibers as a welding wire in combination with a temperature controlled laser process. The goal of the study was to prove the feasibility of the laser welding process and to identify the process window. In order to join complex fused silica parts, a CO2 laser heats up the glass components as well as the glass fiber. Essential for the welded glass component is the through-weld, which ensures the stability and transparency. During the welding process, pores might be enclosed in the joint zone, which should be prevented as far as possible. The study investigates the influence of different process parameters, such as the defined welding temperature, laser focal spot size, wire feed rate and feed rate, on the welding outcome. In addition, the influence of the fiber coating on the material composition in the joint zone was examined. Compared to the manual process, laser welding with glass fiber as a filling material leads to a highly reproducible process enabling a high automation level.