Improved Weld Bead Geometry Modeling and Predictive Temperature Optimization in Direct Energy Deposition (DED) Additive Manufacturing as Demonstrated in Wire Arc Additive Manufacturing (WAAM)

Abstract

Directed Energy Deposition (DED) and Wire Arc Additive Manufacturing (WAAM) offer significant advantages for the fabrication of large-scale metallic components due to their high deposition rates and reduced material waste compared to conventional manufacturing processes. Deposition efficiency is often limited by the need to maintain acceptable interpass temperatures during fabrication. Excessive heat accumulation can alter bead geometry, increase residual stresses, reduce dimensional accuracy, and negatively affect material properties. Current industrial practice commonly relies on fixed interpass cooling pauses or operator judgment, which may result in unnecessary production delays or inconsistent thermal management.

This dissertation presents the development, verification, and validation of the Print Interpass Cooling Pause Optimization (PICPO) software package, a predictive thermal modeling methodology designed to optimize interpass cooling pauses without requiring real-time process monitoring or closed-loop machine control. PICPO operates as a pre-process simulation tool that converts WAAM toolpaths into transient three-dimensional thermal simulations that predict temperature evolution throughout a build. Using these predictions, the framework identifies opportunities to reduce cooling delays while maintaining user-defined thermal constraints with consistent or improved material results.