Coaxial Monitoring and Characteristic Analysis of Plasma Optical Signal in Laser Spot Welding
The plasma produced by laser welding contains a lot of relevant information that can reflect the welding quality.The optical signal of plasma collected by photoelectric sensor can effectively monitor the laser welding quality.A coaxial monitoring system of plasma optical signal in laser spot welding was built,and the analysis of short-time energy of the collected optical signal was carried out.The experimental results show that the workpiece surface has a strong reflection on the laser at the initial stage of welding.When the base metal forms a molten pool,the plasma concentration increases gradually and the welding process tends to be stable.At this time,the optical signal intensity of the plasma reaches the maximum.With the increase of welding time,the molten pool collapses,the stability of plasma becomes worse,the intensity of light signal becomes weaker and the fluctuation becomes larger.At the moment that the workpiece is welded through,the plasma light signal intensity is significantly reduced.
laser spot weldingplasmaoptical signalshort time energycoaxial monitoring
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