Closed-Loop Process Control for Electron Beam Direct Manufacturing

The electron beam free form fabrication process (EBFFF) holds great promise for industry as a disruptive technology based on additive manufacturing of near net shape, high value engineered materials. The development efforts are structured to review and compare multiple process feedback systems for identifying molten pool characteristics and perform a series of open loop process parameter tests to identify critical process control variables. The use of backscattered electrons and secondary emissions which are a byproduct of the EBFFF process will be investigated for suitability as a way to detect and measure critical features of the molten pool and compare with traditional optical based techniques commonly used in non-vacuum applications. A summary report including a detailed outline for the manufacture and implementation of a closed loop process control system, based on controlling critical EBFFF process variables as a result from input variables derived from the molten pool will be presented. BENEFIT: Implementation of a closed loop process control system is anticipated to speed up industry and regulatory approval of the EBFFF process. Additionally it is expected that a closed loop control system will allow for increased repeatiblity and consistency in resulting material properties as well as improving the processes ability to provide even better near net shape performance.