Welding of fused silica with femto second lasers enables new design options

Laser based joining of glass parts for industrial manufacturing applications is demonstrated. The joining partners are bonded reliably with excellent strength. Best application results are obtained using ultra short pulses with high and changing repetition rate, which is adapted exactly to a good thermal management with low stress. The process is based on multi-photon absorption inside the bottom glass resulting in joint welding by heat accumulation. The comfortable process window is suitable for industrial production requirements. A sensor identifies the location of the joint. The welding speed is fast compared to known ablation processes with USP lasers. An optical contact between the parts is not necessary. The quality of the welding can be evaluated in a non-destructive way. The glass surfaces near the welding process qualify for high laser power utilization because there is no glue involved. The obtained welds can hermetically seal a glass casing. A range of production tools is set up to manufacture parts. The new process enables glass to be used as an engineering material with the necessary flexibility to construct complex unities by utilization of femto second laser welding.