Transient Melt Pool Response in Electron Beam Additive Manufacturing

Wire feed electron beam additive manufacturing processes are candidates for manufacturing and repair in the aerospace industry.  For process stability, control of melt pool dimensions is imperative.  This can be achieved via feedback and/or feedforward control approaches.  However, for either approach, the time needed for a change in process variables to translate into changes in melt pool dimensions is a critical concern.  In this research, results from finite element simulations are presented quantifying the transient response of melt pool dimensions to rapid changes in process variables.  Transient responses are determined over a wide range of process variables yielding a range of response times across processing space.  Furthermore, results suggest that similarities in response times and response behaviors exist over wide ranges of process variables, greatly simplifying understanding and ultimate application of the work.  Model results are compared to experiments performed at NASA Langley on their EBF³ equipment.