Contamination suppression of coupling glass during vacuum laser welding

Abstract

In vacuum laser welding, a laser beam is irradiated into a chamber through a coupling glass exposed to contamination. A conical protective system for the coupling glass is suggested, and contamination is analysed via simulation and experiments based on the conical component height and the gas flow rate. Stable descending flow is a key to suppressing the contamination, which affects the particle ascending velocity, horizontal deflection of particles and number of residual particles. The laser transmission area can be protected using a gas flow rate of 1.0 L min−1 or a cone height of 90 mm for the conical component. The conical protective system demonstrates excellent contamination suppression capability. The simulation-based approach can provide an effective design for the protective system.