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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. [ABSTRACT FROM AUTHOR]

The paper deals with the laser cladding application to improve wear properties of cutting edges, making use a fiber laser source. This type of laser is chosen due to the small dimension of the clad cross section that has to be rebuilt. The paper is aimed at obtaining good cladding layers using high content of WC as reinforcement phase, which mainly means a clad free of cracks and pores. In order to obtain very high hardness values of the clad surface, the deposited material is constituted by an high percentage of tungsten carbides (over 85% in weight), while the matrix is a standard cobalt powder. A preliminary experimental campaign allowed to investigate the process parameters which mainly affect the clad quality in terms of pores and cracks absence. Then the role of the three most affecting parameters, i.e. laser speed, laser power and shielding gas, was highlighted in order to better investigate the overall clad attributes, such as micro-hardness, geometry, integrity (pores and cracks) and dilution with the substrate steel. As a result, improved work condition is found, which produces clad with no pores, no crack and high hardness. [ABSTRACT FROM AUTHOR]