Laser welding with oscillation laser beams enables control of the heat input distribution. In this study, we attempted to develop a narrow-gap welding process with oscillation laser welding. This process is expected to prevent a lack of fusion because the entire bottom to the groove can be melted by the oscillation laser. As the first step of the study, bead-on-plate welding experiments with an oscillation laser beam were performed to investigate the relationship between the welding conditions and welding results. The experiments revealed that the oscillation conditions strongly affect the welding penetration shape. It was clarified that the wire melting phenomena in oscillation laser welding differed from those of straight (nonoscillation) laser welding. Additionally, narrow-gap laser welding experiments were performed to investigate the relationship between the oscillation conditions and gap width. The results confirmed the effectiveness of oscillation laser welding for narrow-gap welding.

Laser welding with oscillation laser beam enables control of the heat input distribution. In this study, we attempted to develop a narrow gap welding process with oscillation laser welding. This process is expected to prevent lack of fusion because the entire bottom of the groove can be melted by the oscillation laser. As the first step of the study, bead-on-plate welding experiments with an oscillation laser beam were performed to investigate the relationship between the welding conditions and welding results. The experiments revealed that the oscillation conditions strongly affect the welding penetration shape. It was clarified that the wire melting phenomena in oscillation laser welding differed from those of straight (non-oscillation) laser welding. Additionally, narrow gap laser welding experiments were performed to investigate the relationship between the oscillation conditions and gap width. The results confirmed the effectiveness of oscillation laser welding for narrow gap welding.

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Multi-layered pulse MAG welding by robots is used for large structures. The sensing technology for the detection of defects is crucial towards improving the productivity and quality of robotic welding. The authors have developed a system that detects welding defects (blowholes) by utilizing welding current and voltage waveform data. By processing the measurement data, it is possible to detect welding defects with a probability of 95% or better. The developed defect detection system has been introduced in the company's robotic welding systems.