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Experiments were performed with high power electron beam-based DED-AM, with processing powers ranging from 10 to 25 kW and velocities ranging from 30 to 60 ipm. The single bead parameters that were processed, along with a photograph of the processed substrate, are shown.
These results show strong agreement between the FEA simulation results and experiment.
The overarching objective of this project was to implement multi-sensor thermal imaging in commercially available DED-AM systems, and to couple this sensor data with process knowledge in order to develop tools to ensure a consistent and/or desired thermal profile.
Metal-based directed energy deposition additive manufacturing (DED-AM) and repair processes are in need of process monitoring and control technologies to improve process robustness. Recognizing that microstructure and distortion are driven by the thermal conditions during the build, end users need to have confidence that they can predict, control, and verify the thermal distribution in the deposit throughout the manufacturing process. Such technologies are critical for process certification and wider adoption within the aerospace and energy industries.
The overarching objective of this project was to implement multi-sensor thermal imaging in commercially available DED-AM systems, and to couple this sensor data with process knowledge in order to develop tools to ensure a consistent and/or desired thermal profile. Since the thermal history dictates microstructure development, achieving this objective promises to significantly reduce the need for costly and time-consuming post-process inspection.
An additional objective of this project was to ensure multi-sensor thermal imaging sensors were made available to end users through integration in commercially available AM systems.
Technologies developed at PSU’s Center for Innovative Materials Processing through Direct Digital Deposition (CIMP- 3D) that enabled mapping of sensor data to X-Y-Z position during the deposition were integrated into commercial DED-AM systems. This involved transitioning both hardware modifications and custom software code to the AM Equipment Suppliers on the team.
Process map techniques originally developed at CMU were extended across a broader range of operating space. These process maps link power, velocity, and melt pool characteristics to prior grain structure during Ti-6Al-4V depositions. To capture results at both the low and high end of the energy spectrum, experiments were conducted on both the Optomec Laser Engineered Net Shaping (LENS) system at CIMP-3D and on Sciaky’s Electron Beam DM system. The results of this study were used to fashion and demonstrate a real-time microstructure controller.
The developments in this project made significant strides in assessing the use of multi-sensor thermal imaging data for process monitoring and control of DED-AM processes.
Specific accomplishments include: