| Abstract Scope |
Gathering thermal radiation signatures via in-situ monitoring allows a more comprehensive understanding of the complex thermal history inherent to the LPBF process — and its effect on part performance. One approach, integrated into our open-architecture LPBF system, involves multi-wavelength pyrometry (MWP). As described in our prior works, MWP permits accurate extraction of thermal signatures produced during the print process, including a measure of the emissive power of the target — solving the emissivity problem, and allowing experimentally accurate, spatially resolved temperature readings.
In this work, we will discuss the steps and tests performed that contribute to that accuracy: angular dependence tests to characterize the effects of mirrors and viewports along the optical path, achromatic aberration tests to quantify the effects of measuring outside the instrument's focal length, exposure tests for fine-tuning data acquisition of features smaller than the target area, and a blackbody calibration to ensure accurate absolute thermal measurements. |