An algorithm for trajectory planning of complex surface parts for laser cladding remanufacturing

This paper aims to solve the problem of laser cladding for complex parts, a trajectory planning method for complex parts is proposed. First, the part model is transformed into stereolithography (STL) files, the plane groups are established where the spacing of plane groups is determined by the overlap ratio, and the direction is perpendicular to the laser scanning. Further, to obtain the excellent cladding performance, a search algorithm based on the height error of adjacent cladding is proposed to select effective points. After this, adjacent points are clustered to a dataset according to the relative position that decided by the angle. Meanwhile, the position and the attitude of all points are calculated by the geometrical characteristics and then stored. The cooperate work of positioner and robot is adopted, the attitude of the current point is adjusted using the positioner, that is, the molten pool of the current point is in a horizontal state, which can ensure the forming accuracy of curved parts after cladding. Finally, the cladding experiment of curved surface parts is carried out. The results of the analysis showed that the coating had a smooth surface and a compact structure without defects. This method can be applied in other curved parts.

Multi-objective numerical simulation of geometrical characteristics of laser cladding of cobalt-based alloy based on response surface methodology

The objectives of this study are to optimize the key process parameters of laser cladding remanufacturing parts, improve the sealing quality of the hemispherical valve and prolong and improve its service life and reliability. A high-power fiber-coupled semiconductor laser was used to fabricate a single Co-based alloy cladding layer on the pump valve material ZG45 plate. The key process parameters of laser power, scanning speed and powder feeding rate in the process of laser remanufacturing are taken as optimization variables, and the coating width, coating height, coating depth, aspect ratio and dilution rate are taken as response indexes. Based on the response surface analysis method, the central compound experiment is designed using Design-Expert software. The variance analysis of the experimental results is performed, and the regression prediction model of the process parameters relative to the corresponding index is established. Through analysis of the established perturbation diagram and three-dimensional response surface, it is concluded that the main influence factors of melting width and penetration depth are laser power and positive effect, and the main influence factors of melting height are scanning speed and negative effect. The average error of each regression prediction model is lower than 10%. The above research work has important guiding significance for optimizing the process parameters and improving the cladding quality of cobalt-based alloy on ZG45.