This research addresses the prediction of transient changes melt pool size in laser-based additive powder fusion processes. Additive processes are designed to deposit features onto an existing part, as a means for more efficient part manufacture or part repair. Melt pool size is a key process characteristic that must be controlled to allow the precise deposition of complex features. An understanding of transient changes in melt pool size is an important part of efforts to control melt pool size in real time, via thermal imaging or other feedback control systems. In this research, a process map approach formerly applied to the analysis of steady-state melt pool size is extended to the study of transient changes in melt pool size due to a step change in laser power or velocity. Changes in melt pool size vs. distance or time are presented in quasi-nondimensional form, allowing results from simulations spanning the range of practical process parameters to be presented in compact form. Process map plots are used to quantify the range of times needed to achieve typically desired melt pool size changes. These times establish lower bounds on response times for any thermal feedback control system.
展开▼
