An Algorithm for Inverse Modeling of Layer-by-Layer Deposition Processes

Metallic parts can be made by deposition of liquid metal in a layer-by-layer fashion. By this means, layered structures can be produced that are made up of overlapping reinforced droplets. In particular, prototypes, i.e., customized parts and tooling, can be produced in this way. In order that layer-by-layer fabrication techniques transition from prototyping to manufacturing, however, the processes must be made reliable and consistent. Accordingly, detailed microstructural and thermal characterizations of the product are needed to advance manufacturing goals based on layer-by-layer deposition processes. The inherent complexity of layer-by-layer deposition processes, characteristic of energy and mass deposition processes in general, is such that process modeling based on theory, or the direct-problem approach, is extremely difficult. A general approach to overcoming difficulties associated with this inherent complexity is the inverse-problem approach. Presented here is an algorithm for inverse modeling of heat transfer occurring during layer-by-layer deposition, which is potentially adaptable for prediction of temperature histories in samples that are made by layer-by-layer deposition processes.