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

A fundamental understanding of how process variables relate to deposit char acteristics is essential for solid free form fabrication (SFF) process cont rol. In this article, recent research into modeling and understanding solid ification-related phenomena in laser-based direct metal SFF processes is su mmarized. A "process map" approach is outlined, which provides nonlinear th ermomechanical 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 structu res are presented, and process-related insights from them are described Wor k underway to develop additional process maps, including those for microstr uctural control, is also summarized.