The role of process variables in laser-based direct metal solid freeform fabrication

A fundamental understanding of how process variables relate to deposit characteristics is essential for solid free form fabrication (SFF) process control. In this article, recent research into modeling and understanding solidification-related phenomena in laser-based direct metal SFF processes is summarized. A "process map" approach is outlined, which provides nonlinear thermomechanical model results for key deposit characteristics over the full range of relevant process variables. Process maps for predicting melt pool size, therinal gradients and maximum residual stress in thin-walled structures are presented, and process-related insights from them are described Work underway to develop additional process maps, including those for microstructural control, is also summarized.