The AMADA MM-L400A Laser Weld Monitor is an advanced in-process monitoring system designed for precise good/bad judgment of laser welding and preventive maintenance, supporting both fixed optics and scanner heads. This new product significantly enhances monitoring capabilities by detecting not only infrared radiation but also reflected light and visible light (plasma), allowing for comprehensive analysis against preset standard waveforms. It features a fine resolution of 1 µs, enabling monitoring of both CW and pulsed lasers. The user-friendly MS-Viewer software facilitates intuitive adjustments for measurement triggers, sensor sensitivity, and envelope settings, simplifying waveform comparison. Key features include comparison judgment for detecting issues like workpiece gaps or insufficient penetration, and an optional scanner head support for area-based monitoring, which uses four sensors to easily detect penetration during scanner welding by identifying scattered metal. The system supports detection wavelengths across visible light (400-800 nm), reflective light (1060-1080 nm), and near-infrared light (1300-1700 nm), and complies with CE marking. Its robust design and detailed monitoring capabilities make it an essential tool for ensuring welding quality and process stability.