Validation of a Digital Twin for Cold Spray Supersonic Deposition: A Literature-Based Case Study for Melt-less Additive Manufacture of IN718

Abstract

Cold spray is a coating process as well as rapidly emerging and scalable solid-state robotic additive manufacturing technology. Its high deposition rates (+10 kg/hr) allow for manufacturing of near net shape large metal and composite structures. For example, it is possible to additive manufacture near net shape IN718 parts directly from powder in addition to coating and repair of critical components for high-temperature applications and aviation industries. The challenge is that successful cold spray deposition of IN718 depends on careful optimization of multiple processing parameters. This study examines a developed digital twin for cold spraying to overcome the time-consuming optimization process for IN718 deposition with consideration of independently published data. This approach was taken to achieve realistic validation for Cold Spray Digital Twin (CSDT) that could eventually lead to an autonomous cold spray deposition capability. The CSDT was constructed according to a calibrated and validated three-dimensional (3D) multicomponent CFD model for visualization of cold spray supersonic flow combined with all input parameters of the industry-scale cold spray systems. The predicted in-flight particle temperature and velocity that are difficult to measure experimentally are reported. The results from CSDT simulations were in agreement with the three experimental studies with consideration of 10-15% error achieved through the 3D model calibration process. The CSDT capabilities were successfully applied to visualize and discuss the IN718 deposition in relation to cold spray nozzle, shockwave formation, nozzle, and substrate heat transfer including the effect of powder feed rate. Overall, CSDT outcomes proved to be a cost-effective tool providing detailed information that otherwise would only be possible through performing challenging experimentations. Analysis of the CSDT outputs presented the opportunity for advancing our understanding of cold spray bonding and improving process efficiency using industry-scale cold spray equipment with potential improvements in designing future cold spray systems.