| Abstract Scope |
Recent studies in optical metrology of laser powder bed fusion (LPBF) indicate that there remains insufficient understanding of the optical phenomena that occur during laser-matter interaction, which limits the accuracy of non-contact measurements for multiphysics model validation applications. One of the first challenges is accurate measurement of the power density distribution (often a two-dimensional gaussian profile) of high-power lasers under conditions of interest for LPBF. Furthermore, process byproducts (including metal vapor, condensate, and ejecta) can interact with the light propagating to (and from) the melt pool, which can attenuate, scatter, or otherwise distort the power density distribution that is delivered to the melting surface; preliminary results of measuring the effects of process byproducts are discussed. Finally, metrology for quantifying the total laser power reflected from the laser-matter interaction (used to approximate laser absorption), as well as for visualizing the directional distribution of reflected laser power, will be discussed. |