Monday, 11 October 2004 - 10:05 AM

This presentation is part of : Metal Forming I

The Relationships between Process Variables and Melt Pool Size in Laser Additive Manufacturing Processes

Jack L. Beuth, Andrew J. Birnbaum, and Pruk Aggarangsi. Carnegie Mellon University, Department of Mechanical Engineering, Pittsburgh, PA 15213

This research addresses the control of steady-state and transient melt pool size in laser additive manufacturing processes. Laser additive manufacturing refers to advanced laser-based fusion processes used to add features to 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. For the case of steady-state conditions, numerical simulations are used to construct non-dimensional plots (termed process maps) that quantify the effects of changes in part height, laser power, deposition speed and part preheating on melt pool size. The process map approach is further used to consider the effect of process size scale on the insensitivity of melt pool size to small changes in process parameters (related to process robustness). 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. The process map approach applied to the steady-state problem is extended to the study of transient changes in melt pool size due to a step change in laser power or velocity. Times needed to achieve desired melt pool size changes are quantified, establishing lower bounds on response times for any thermal feedback control system.

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