Algorithm and Implementation of Laser Cladding with Equal Overlapping Ratio on Free-Form Surface

The thickness of cladding layers on free-form surface tends to be nonuniform owing to an instable overlapping ratio in the laser cladding process. In this paper, a trajectory generation algorithm for a laser cladding with an equivalent overlapping ratio on a free-form surface is proposed to solve this problem. A depth camera was used to collect the point cloud data on the whole surface. A point cloud beam was fitted as initial cladding layer, and a processing point set was obtained using the equidistant step method. The contour along the vertical direction of the cladding layer was identified by cross-section slicing, and equidistant points of processing points were fitted for ensuring the equality of the overlapping ratio. The next processing trajectory was fitted from the obtained equidistant point set until it traversed the entire surface. The posture of a cladding nozzle was determined along the normal vector direction of the processing points to keep the axis of the nozzle perpendicular to the machined surface. The results of the surface cladding experiment conducted on a hemispherical end socket reveal that cladding layer with equal overlapping ratios can be obtained by combining the equidistant trajectory algorithm and posture adaptation of the nozzle. In addition, the cladding layer on the free-form surface exhibit uniform thickness and high microhardness and have no obvious defects such as inter-channel bulging or depression.