Generic implementation of path design for spray deposition: Programming schemes, processing and characterization for cold spraying

Abstract

Applications in thermal and kinetic spraying increasingly aim for coating of parts with complex geometries. So far, respective robot programming for the required path during deposition is usually adjusted individually in time-consuming procedures. Thus, it is essential to develop methods that allow a fast adaptation to part geometries and production conditions as well as possible quality control. To tackle these problems, this work addresses novel strategies for robot programming and post-spray analyses. Here, the developed application can handle complex parts of arbitrary geometry in the form of CAD files to generate precise spray paths. Robot offline programming allows for process simulation, analysis and optimization. Robot kinematics was employed to evaluate the effect of the planned spray paths on the spraying process. By optical scanning profilometry, the layer-by-layer deposit build-up could be monitored for quality control, as well as for the determination of the final overall coating thickness. To validate the capability of the proposed strategy, the entire procedure was tested by cold spraying onto a complex workpiece. The results show that the proposed method enables a fast generation of the required paths and allows for accurate transfer to the spray procedures. Different path planning ways influenced the robot performance and thus the deposition. Based on the universal layout of the applied methods, the strategies can also be applied for thermal spraying in general, considering individual boundary conditions. With respect to cold spraying, the implementation framework of this study provides a good basis for part repair and additive manufacturing.