Thermal Controls for Uniform and Consistent Material Quality in DED Additive Manufacturing Processes

Stratonics has proposed a plan to develop technology for thermal control of DED processing to achieve uniform and consistent material quality. Thermal control will be applied on both the micro and macro scale, enabling stable deposition of melt pool solidification and associated initial microstructure on the spatial scale of the melt pool size, and enabling stable cooling from initial material states immediately following the melt pool to much cooler states where the microstructure has become stable. On the microscale, the laser heats both the prior layer and new powder delivered by the machine to form the melt pool, hence a rapid heating cycle which is immediately followed by a rapid cooling cycle. As the melt pool cools and solidifies, the initial microstructure is set. The newly formed microstructure and its microstructure transition thru repeated cooling cycles as more and more layers are applied. As the material is cooling its microstructure continues to migrate towards its equilibrium or final condition. Temperature sensors and process controls are developed to control this process for repeated thermal trajectories; hence the control system directs the final microstructure and material performance in a uniform and consistent manner. Such a thermal controlled DED process will provide for parts with uniform materials properties and with consistency with production volumes of AM parts.