Controlling Thermal History to Improve LPBF Process Outcomes

We present a study where we attempted to improve LPBF process outcomes (e.g. microstructure, geometrical accuracy, distortion, and swelling) solely by modifying the thermal history of components being built. We demonstrated the viability of this approach through two builds with one acting as a control and the other with thermal history modification. The thermal history modifications were executed in a feed-forward manner, by leveraging the results of fast graph theory thermal models and real-time IR camera data to modify process parameters. The results were promising, showing that controlling parameters and scan strategies for a more consistent inter-layer temperature distribution in the components resulted in better geometric accuracy, less unwanted sintering of through-channels and better overhang structures.

This paradigm of process development, leveraging only thermal history is a marked departure from the conventional parameter-focused design-of-experiments approach for applications and materials development. This process shows potential for easy LPBF platform-agnostic parameter and materials development.