Monitoring of cover slide degradation during fibre laser cladding

This work concerns the design, fabrication and performance analysis of a cover slide monitoring system for an active-fibre laser cladding head. The cover slide prevents contamination of the optical chain by the process powder. The possibility of monitoring the life of this component in real time is important in gaining information regarding failure and degradation state. Cover slide monitoring was achieved using two approaches: one based on the measurement of reflectivity and the other based on that of temperature. In this way light scattered from the protective glass and the temperature of the protective glass holder were acquired. The developed monitoring device is compact and able to detect both small (cracks, for example) and large defects (opacity, for example) on the surface of the protective slide. The performance of the monitoring system was validated by conducting several case studies that reproduced normal industrial practices in the laser cladding field.