ABSTRACT
Defects and process irregularities influence the bonding strength and thus the stability and lifetime of welded glass components. The present paper proposes to monitor the laser-based glass welding process by means of a single photodetector that records the radiation emitted from the laser-induced plasma. It is shown that the plasma emission provides information about irregularities of the welded seam height, gap bridging, process interruptions, and the position of the seam. The method is suitable for different welded glass types.
ABSTRACT
During welding of glass with ultrafast lasers, an irregular formation of weld seams was prevented by modulation of the average laser power and spatial beam shaping. The formation of individual molten volumes in regular intervals was achieved by means of power modulation, resulting in a predictable and reproducible weld seam with a regular structure. At constant average power, a homogeneous weld seam without a periodic signature was alternatively achieved by means of a shaped beam generating an elongated interaction volume and resulting in a continuous melting of the material. The influence of the two approaches, and their combination on the process dynamics, was analyzed by means of high-speed videos of the plasma emission and of the formation of the seams.
ABSTRACT
Various process regimes were observed during microwelding of glass with bursts of ultrashort laser pulses. Two major welding regimes and various subregimes were identified for two different materials. The radiation emitted by the laser-induced plasma was used to monitor different regimes that characterize glass microwelding. A comprehensive understanding of the various process regimes can be exploited to use the regimes according to their specific advantages, especially for industrial applications.
