Strategies and Analyses for Robot Trajectory Optimization in Thermal and Kinetic 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. The design of the method and workflow follows routes of smart manufacturing and should enable fast and accurate implementation into spray procedures. Here, the developed application can handle complex parts of arbitrary geometry in the form of CAD files. Supported features include (i) cutting the objects according to the object boundary, (ii) creating self-intersecting curves, (iii) generating a set of index-sequence-based spatial discrete points and (iv) reordering the discrete points to generate adaptive paths. Robot offline programming allows for process simulation, analysis and optimization of the robot kinematics. 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. The entire procedure was tested by cold spraying onto a complex workpiece, validating the capability of the proposed strategy. 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.

A Review of Advances in Cold Spray Additive Manufacturing

“…Furthermore, Kotoban et al [165] investigated the relationship between the shape of a single-track coating and the DE, concluding that in the first layer deposition, the particles on the jet periphery have a slight decrease in DE compared to the jet core, producing a triangle shape deposit that sharpens layer by layer. Finally, Wu et al [166] developed a model to compensate the layer thickness by optimizing the robot velocity at the different regions on the substrate surface, resulting in a smoother CS-ed material surface.…”