Cold Spray In The Realm Of Additive Manufacturing PDF Download

Cold spray (CS) is a solid-state coating deposition technology that has recently been applied as an additive manufacturing (AM) process to fabricate individual components. This potential AM process is attracting more and more attention because of its advantages: high-forming efficiency, low temperature, and no phase changing of materials. These advantages make CS able to form large-volume objects to become an efficient and effective AM process. Nowadays, new advances in cold spray additive manufacturing (CSAM) call for new process implementation to improve the manufacturing accuracy and flexibility. Therefore, the purpose of this study is to enhance CS-based AM through the modeling and planning of the robotic CS process. The work of this thesis consists of three parts.Firstly, efforts have been dedicated to design and implement a new framework for CSAM. In this part, a concept of modular system is presented. Here, the current CSAM system is decomposed into different modules in order to understand the physical and functional relationships between the key elements of the entire system. This physical and functional modularity is an indispensable necessity to promote hybrid AM processes. New modules, such as in-situ measurement module, inter-process module can be integrated into the framework to bring more possibilities to the conventional CS process. It is revealed that system modularity is suitable to revolutionize the CSAM method and conduction. It can be seen that to fully exert the potential of CSAM, efforts are still required to integrate and coordinate more technologies with the help of the proposed modular framework.Secondly, a novel approach is presented to simulate the CS deposition. Here, a three-dimensional geometric model of the coating profile based on Gaussian distribution is developed. The model is combined with robot trajectory and processing parameters to simulate the evolving CS deposits. In addition, it can offer accurate profile prediction in the robot off-line programming platform, especially in case of shadow effects, which enables the integration of robot programming with simulation to better control the coating process. The results of both numerical and experimental verifications show that this proposed method has a good prediction accuracy for practice.At last, compared with the current bulk-based volume-forming strategy (e.g. a tessellation-based method), this study proposes a new spray strategy that considers the characteristics and kinematic parameters of cold spray to enhance stable layer building for 3D shape forming. Both simulation and experiments are conducted for method verification. Layer built benchmarking test objects have better shape accuracy than that of existing methods. This implies that the proposed method makes CS a real and layer-by-layer ready AM process for 3D shape forming.